A study on the U speciation in groundwater of a hard rock aquifer in South India

International Nuclear Information System (INIS)

Thivya, C.; Chidambaram, S.; Thilagavathi, R.; Nepolian, M.; Adithya, V.S.; Tirumalesh, K.; Prasanna, M.V.

2015-01-01

Speciation of uranium indicates the contribution of this ion into different species. An attempt has been made to study the spatial and temporal variations of U speciation in the hard rock aquifer of South India. The major rock types have granulite facies with high grade metamorphic rocks and younger intrusive. It also comprises of Fissile hornblende biotite gneiss, Charnockite, Quartzite, Granite and Flood Plain Alluvium. A total of 108 samples were collected from the handpumps of the study area for two seasons (Pre monsoon and South West monsoon). The groundwater samples were analysed for U and other ions like Ca 2+ , Mg 2+ , Na + and K + , HCO 3 - , Cl - , SO 4 2- , PO 4 3- , NO 3 - , F - , H 4 SiO 4 , pH, EC and TDS using standard procedures

Deep Keck u-Band Imaging of the Hubble Ultra Deep Field: A Catalog of z ~ 3 Lyman Break Galaxies

Science.gov (United States)

Rafelski, Marc; Wolfe, Arthur M.; Cooke, Jeff; Chen, Hsiao-Wen; Armandroff, Taft E.; Wirth, Gregory D.

2009-10-01

We present a sample of 407 z ~ 3 Lyman break galaxies (LBGs) to a limiting isophotal u-band magnitude of 27.6 mag in the Hubble Ultra Deep Field. The LBGs are selected using a combination of photometric redshifts and the u-band drop-out technique enabled by the introduction of an extremely deep u-band image obtained with the Keck I telescope and the blue channel of the Low Resolution Imaging Spectrometer. The Keck u-band image, totaling 9 hr of integration time, has a 1σ depth of 30.7 mag arcsec-2, making it one of the most sensitive u-band images ever obtained. The u-band image also substantially improves the accuracy of photometric redshift measurements of ~50% of the z ~ 3 LBGs, significantly reducing the traditional degeneracy of colors between z ~ 3 and z ~ 0.2 galaxies. This sample provides the most sensitive, high-resolution multi-filter imaging of reliably identified z ~ 3 LBGs for morphological studies of galaxy formation and evolution and the star formation efficiency of gas at high redshift.

A U-Shaped Slot UWB Antenna with Flexible and Wide Tunable Dual Notch Band

Directory of Open Access Journals (Sweden)

Zhang Zhongmin

2016-01-01

Full Text Available A coplanar waveguide (CPW fed ultra-wideband (UWB antenna with flexible and wide tunable dual bandnotched characteristics is proposed in this paper. The dual band-notched function is achieved by using an U-shaped slot inserted into the ellipse radiation patch and by using an elliptic parasitic slit placed near the ground plane. The wide tunable band-notched characteristic is implemented by adjusting the length of U-shaped slot and by adjusting the length of ellipse parasitic slit. The design aims to achieve wide reconfigurable band-notched features on the UWB antenna. The simulated results indicate that the proposed antenna has a wide bandwidth (VSWR under 2 from 2.9GHz to 12.6GHz with fractional bandwidth of 125%, and has a wide tunable notch band center frequency from 4.5GHz to 12.4GHz.

DEEP U BAND AND R IMAGING OF GOODS-SOUTH: OBSERVATIONS, DATA REDUCTION AND FIRST RESULTS ,

International Nuclear Information System (INIS)

Nonino, M.; Cristiani, S.; Vanzella, E.; Dickinson, M.; Reddy, N.; Rosati, P.; Grazian, A.; Giavalisco, M.; Kuntschner, H.; Fosbury, R. A. E.; Daddi, E.; Cesarsky, C.

2009-01-01

We present deep imaging in the U band covering an area of 630 arcmin 2 centered on the southern field of the Great Observatories Origins Deep Survey (GOODS). The data were obtained with the VIMOS instrument at the European Southern Observatory (ESO) Very Large Telescope. The final images reach a magnitude limit U lim ∼ 29.8 (AB, 1σ, in a 1'' radius aperture), and have good image quality, with full width at half-maximum ∼0.''8. They are significantly deeper than previous U-band images available for the GOODS fields, and better match the sensitivity of other multiwavelength GOODS photometry. The deeper U-band data yield significantly improved photometric redshifts, especially in key redshift ranges such as 2 lim ∼ 29 (AB, 1σ, 1'' radius aperture), and image quality ∼0.''75. We discuss the strategies for the observations and data reduction, and present the first results from the analysis of the co-added images.

Summary and Analysis of the U.S. Government Bat Banding Program

Science.gov (United States)

Ellison, Laura E.

2008-01-01

This report summarizes the U.S. Government Bat Banding Program (BBP) from 1932 to 1972. More than 2 million bands were issued during the program, of which approximately 1.5 million bands were applied to 36 bat species by scientists in many locations in North America including the U.S., Canada, Mexico, and Central America. Throughout the BBP, banders noticed numerous and deleterious effects on bats, leading to a moratorium on bat banding by the U.S. Fish and Wildlife Service, and a resolution to cease banding by the American Society of Mammalogists in 1973. One of the main points of the memorandum written to justify the moratorium was to conduct a 'detailed evaluation of the files of the bat-banding program.' However, a critical and detailed evaluation of the BBP was never completed. In an effort to satisfy this need, I compiled a detailed history of the BBP by examining the files and conducting a literature review on bat banding activities during the program. I also provided a case study in managing data and applying current mark-recapture theory to estimate survival using the information from a series of bat bands issued to Clyde M. Senger during the BBP. The majority of bands applied by Senger were to Townsend's big-eared bat (Corynorhinus townsendii), a species of special concern for many states within its geographic range. I developed a database management system for the bat banding records and then analyzed and modeled survival of hibernating Townsend's big-eared bats at three main locations in Washington State using Cormack-Jolly-Seber (CJS) open models and the modeling capabilities of Program MARK. This analysis of a select dataset in the BBP files provided relatively precise estimates of survival for wintering Townsend's big-eared bats. However, this dataset is unique due to its well-maintained and complete state and because there were high recapture rates over the course of banding; it is doubtful that other unpublished datasets of the same quality exist

DEEP KECK u-BAND IMAGING OF THE HUBBLE ULTRA DEEP FIELD: A CATALOG OF z ∼ 3 LYMAN BREAK GALAXIES

International Nuclear Information System (INIS)

Rafelski, Marc; Wolfe, Arthur M.; Cooke, Jeff; Chen, H.-W.; Armandroff, Taft E.; Wirth, Gregory D.

2009-01-01

We present a sample of 407 z ∼ 3 Lyman break galaxies (LBGs) to a limiting isophotal u-band magnitude of 27.6 mag in the Hubble Ultra Deep Field. The LBGs are selected using a combination of photometric redshifts and the u-band drop-out technique enabled by the introduction of an extremely deep u-band image obtained with the Keck I telescope and the blue channel of the Low Resolution Imaging Spectrometer. The Keck u-band image, totaling 9 hr of integration time, has a 1σ depth of 30.7 mag arcsec -2 , making it one of the most sensitive u-band images ever obtained. The u-band image also substantially improves the accuracy of photometric redshift measurements of ∼50% of the z ∼ 3 LBGs, significantly reducing the traditional degeneracy of colors between z ∼ 3 and z ∼ 0.2 galaxies. This sample provides the most sensitive, high-resolution multi-filter imaging of reliably identified z ∼ 3 LBGs for morphological studies of galaxy formation and evolution and the star formation efficiency of gas at high redshift.

The Rapid Formation of Localized Compaction Bands Under Hydrostatic Load Leading to Pore-pressure Transients in Compacting Rocks

Science.gov (United States)

Faulkner, D.; Leclere, H.; Bedford, J. D.; Behnsen, J.; Wheeler, J.

2017-12-01

Compaction of porous rocks can occur uniformly or within localized deformation bands. The formation of compaction bands and their effects on deformation behaviour are poorly understood. Porosity may be primary and compaction can occur with burial, or it can be produced by metamorphic reactions with a solid volume reduction, that can then undergo collapse. We report results from hydrostatic compaction experiments on porous bassanite (CaSO4.0.5H2O) aggregates. Gypsum (CaSO4.2H2O) is first dehydrated under low effective pressure, 4 MPa, to produce a bassanite aggregate with a porosity of 27%. Compaction is induced by increasing confining pressure at rates from 0.001 MPa/s to 0.02 MPa/s while the sample is maintained at a temperature of 115°C. At slow compaction rates, porosity collapse proceeds smoothly. At higher compaction rates, sudden increases in the pore-fluid pressure occur with a magnitude of 5 MPa. Microstructural investigations using X-ray microtomography and SEM observations show that randomly oriented localized compaction features occur in all samples, where the bulk porosity of 18% outside the band is reduced to 5% inside the band. Previous work on deformation bands has suggested that localized compactive features only form under an elevated differential stress and not under a hydrostatic stress state. The magnitude of the pore-pressure pulses can be explained by the formation of compaction bands. The results indicate that the compaction bands can form by rapid (unstable) propagation across the sample above a critical strain rate, or quasi-statically at low compaction rates without pore-fluid pressure bursts. The absence of pore-fluid pressure bursts at slow compaction rates can be explained by viscous deformation of the bassanite aggregate around the tip of a propagating compaction band, relaxing stress, and promoting stable propagation. Conversely, at higher compaction rates, viscous deformation cannot relax the stress sufficiently and unstable

U, Th and K contents and metamorphism of Archaean rocks from South-West Greenland

International Nuclear Information System (INIS)

Kalsbeek, F.

1974-01-01

Granulite facies rocks, from the Nordland area, West Greenland, contain six times less U than the amphibolite facies rocks of the Frederikshaab area, and half of the amount of K. The rocks of the Frederikshaab area did not form by retrogression of granulite facies rocks. This study is based on analyses of sand samples which adequately represent the inhomogeneous bed rock. (author)

Evolution of Th and U whole-rock contents in the Ilimaussaq intrusion

International Nuclear Information System (INIS)

Bailey, J.C.; Rose-Hansen, J.; Loevborg, L.; Soerensen, H.

1981-01-01

A great variety of investigations have been made on the distribution of Th and U in the Ilimaussaq alkaline, South Greenland. The major emphasis has been placed on economic assessment of the Kvanefjeld uranium deposit but attention has also been given to the Th and U contents of rocks and minerals outside the deposit. In the present study, we present Th and U values largely obtained by laboratory gamma-ray spectrometric (GRS) analysis of a large collection of representative samples taken from all rock types of the intrusion. The results are discussed in relation to current knowledge and ideas on the petrologic evolution of the Ilimaussaq intrusion. The behaviour of Th and U in igneous systems is moderately well known. During closed-system fractional crystallization, Th and U are generally excluded from the cumulus phases and attain higher levels in successive residual magmas. In most cumulate sequences, they are held in the trapped liquid (mesostasis). In both magmas and cumulates, the Th/U ratio remains virtually unchanged from the ratio of the parent magma. Only a few examples are known where significant amounts of Th-, U-rich cumulus phases (e.g. perovskite, eudialyte) crystallise and disturb the Th/U ratio. At many loctions, fractional crystallization occurred under open-system conditions and Th and U were redistributed by mobile fluids. These are frequently concentrated in roof zones or added to the surrounding country rocks. Elsewhere, post-magmatic Th-U metasomatism may be so intense that few of the primary, magmatic features are preserved. Previous invetigators of Th and U at Ilimaussaq have found evidence for closed- and open-system conditions at different stages of the evolution, and also for post-magmatic metasomatism. (author)

U-Pb isotope systematics in josephinites and associated rocks

Energy Technology Data Exchange (ETDEWEB)

Goepel, C.; Manhes, G.; Allegre, C.J. (Lab. Geochimie et Cosmochimie, I.P.G., 75 - Paris (France))

1990-02-01

Josephinite nodules, composed of metallic nickel iron alloy intergrown with andradite garnet, are found in the peridotitic section of an obducted ophiolite in SW Oregon. The origin of josephinite is widely debated: for example, previous investigation have proposed it as a byproduct of low temperature synserpentinization processes linked to the intrusion of dikes or and its derivation from primitive mantle, conceivably from as deep as the core mantle boundary. We report U-Pb data from josephinites, wyrdite (a rock associated with josephinite) consisting of rutile and ilmente intergrown with silicates, and their surrounding rocks (hornblende diorites and harzburgites). The measured Pb isotopic composition of all decontaminated, leached josephinite metal samples plots in the Pb-Pb diagram just above/in the MORB field, while the first leachates are characterized by higher {sup 207}Pb/{sup 204}Pb ratios. The isotopic Pb composition measured in the leachates of the wyrdite defines a line whose slope corresponds to an age of 159{plus minus}8 Myr. The harzburgites show a wide spread in Pb isotopic compositions; all samples lie above the MORB field and three samples plot to the left side of the 4.55 AE geochron. The hornblende diorite dikes, characterized by the highest U and Pb concentrations of all studied rocks, plot in the MORB field. None of these different rocks is characterized by a single or homogeneous Pb composition. All samples are affected by secondary alteration processes: the circulation of hydrothermal fluids disturbed the dikes and ultramafic rocks and serpentinization processes have affected harzburgites, josephinites, and wyrdites. Thus the Pb isotopic composition measured today represents a mixture of initial Pb, radiogenic Pb and inherited Pb in variable proportions. Concerning the origin of josephinite these results show a close relationship between josephinite, wyrdite, and the dikes. (orig./WB).

Development of two U.H.F. band resonators for application to CO2 laser electro-optical modulation

International Nuclear Information System (INIS)

Egan, M.G.; Blanc, P.; Sexton, M.C.

1980-01-01

The purpose of this report is to describe the design and testing of two U.H.F. band resonators destined for use in the linear electro-optical modulator of the CO 2 Laser Rapid Interferometer diagnostic at present under development for the WEGA Tokamak. The resonators take the form of a re-entrant coaxial line cavity and an interdigital line filter, both of which possess the regions of high electric field necessary to activate the linear electro-optical effect

On the possibility of determining rates of removal of uranium from crystalline igneous rocks using U - series disequilibria - 1: a U-leach model, and its applicability to whole-rock data

International Nuclear Information System (INIS)

Latham, A.G.; Schwarcz, H.P.

1987-01-01

The removal of U from granitic rocks is characterised by 234 U/ 238 U 230 Th/ 234 U > 1. It is notable, from weathered Eye-Dashwa lakes (Canada) granite samples and from the published data, that 230 Th/ 234 U ratios seldom exceed a limiting value of about 2. A U-leach model is discussed in detail which may account for these observations. The model assumes that 230 Th is practically immobile and that the removal of U can then be measured against the decay rate of the unsupported 230 Th. A property of the model is that the isotope ratios reach constant values reflecting a kind of ''secular equilibrium'', and this implies that U is seldom removed faster than the decay of 230 Th. If the limited 230 Th/ 234 U ratios from the data correspond to ''secular equilibrium'' ratios then this allows simple calculation of U-leach rates from any given subsurface sample. (author)

Sorption of Cs, Eu and U(VI) onto rock samples from Nizhnekansky massive

Energy Technology Data Exchange (ETDEWEB)

Petrov, V.; Vlasova, I.; Kalmykov, S. [Lomonosov Moscow State University (Russian Federation); Kuzmenkova, N. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Science (Russian Federation); Petrov, V.; Poluektov, V. [Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences - IGEM RAS (Russian Federation)

2014-07-01

The accepted in Russia concept for high level wastes (HLW) and spent nuclear fuel (SNF) disposal is based on their isolation into the deep underground crystalline rock formations. The 'Eniseysky' area (Nizhnekansky massive) is supposed as the most perspective location for the future HLW and SNF repository. Core materials from different areas of Nizhnekasnsky massive have been studied in terms of petrographic and mineralogical characterization; definition of filtration, elastic, petro-physical and strength properties; estimation of hydrothermal-metasomatic transformation of rocks. We used both undisturbed sliced cores and crushed material for the sorption experiments. Preliminary results of uranium sorption show some significant differences between used rock samples from different depth in sorption rate and pH-dependence. In all cases maximum sorption (more than 90%) is reached in 2-3 weeks. The pH-dependence of sorbed uranium fraction has typical hump-shape: increase of sorption percentage with increasing pH values to 6, plateau (90-98 % of uranium sorbed), decrease of sorption percentage with increasing pH values from 8 due to U(VI) hydrolysis. In the case of cesium the sorption maximum is reached within 10-12 days and in the case of europium - about 5 days. All radionuclides sorbed preferentially onto dark minerals. Local distribution and preferential sorption of cesium, europium and uranium (VI) onto different minerals within the sample were studied by radiography, SEM-EDX, etc. These data accompanying with rock sample composition will allow the development of quantitative model for Cs, Eu and U(VI) sorption onto investigated rocks. Document available in abstract form only. (authors)

The SHRIMP zircon U-Pb dating of felsic volcanic rocks and its geological significance from yutian group in southern jiangxi

International Nuclear Information System (INIS)

Ji Chunyu; Wu Jianhua

2010-01-01

Past researches have showed that the Rb-Sr isochron ages of felsic end member for r hyolite-basalt b imodal volcanic rocks of Yutian Group in the Changpu and Longnan Basin in Southern Jiangxi Province are 175 ∼ 148 Ma, not only does its amplitude change more significantly, but it does not match with the Rb-Sr isochron ages (179 ∼ 173 Ma) of basic end member. As a result, I choose a method of zircon U-Pb dating with a higher accuracy, to obtain the rhyolite in the bottom of bimodal volcanic rocks in the Changpu Basin and the dacite in the top of of bimodal volcanic rocks in the Longnan Basin, whose zircon SHIRMP U-Pb age are respectively (195.2 ± 2.8) Ma and (191 ± 1.7) Ma. What's more, they are both almost the same in the error limit. It shows that the bimodal volcanic rocks in these both two basins are the product of the same session of magma movement. Simultaneously, it explains they form in a flash during the eruption intervals. According to the the newest International Stratigraphic Chart (Gradsrein et al. , 2004), in terms of geological age, the bimodal volcanic rocks in Changpu Basin and Longnan Basin, belonging to the early Early Jurassic. The zircon SHIRMP U-Pb age are distinctly older than the whole-rock Rb-Sr isochron age, it is probably because of the deviation of the dating method for the wholerock Rb-Sr isochron age. The zircon SHIRMP U-Pb age of bimodal volcanic rocks are 191 ∼ 195 Ma in Southern Jiangxi Province, which indicates that there had been an extensional environment. And after the bimodal volcanic activity, The zircon SHIRMP U-Pb age of felsic volcanic rocks are 145 ∼ 130 Ma. Both of the ages shows a as long as 45 Ma quiet period between 190 Ma and 145 Ma. It is unreasonable possible to interpreted by the single pattern of pacific plate subducting to eurasian plate. (authors)

Lyman Break Galaxies in the Hubble Ultra Deep Field through Deep U-Band Imaging

Science.gov (United States)

Rafelski, Marc; Wolfe, A. M.; Cooke, J.; Chen, H. W.; Armandroff, T. E.; Wirth, G. D.

2009-12-01

We introduce an extremely deep U-band image taken of the Hubble Ultra Deep Field (HUDF), with a one sigma depth of 30.7 mag arcsec-2 and a detection limiting magnitude of 28 mag arcsec-2. The observations were carried out on the Keck I telescope using the LRIS-B detector. The U-band image substantially improves the accuracy of photometric redshift measurements of faint galaxies in the HUDF at z=[2.5,3.5]. The U-band for these galaxies is attenuated by lyman limit absorption, allowing for more reliable selections of candidate Lyman Break Galaxies (LBGs) than from photometric redshifts without U-band. We present a reliable sample of 300 LBGs at z=[2.5,3.5] in the HUDF. Accurate redshifts of faint galaxies at z=[2.5,3.5] are needed to obtain empirical constraints on the star formation efficiency of neutral gas at high redshift. Wolfe & Chen (2006) showed that the star formation rate (SFR) density in damped Ly-alpha absorption systems (DLAs) at z=[2.5,3.5] is significantly lower than predicted by the Kennicutt-Schmidt law for nearby galaxies. One caveat to this result that we wish to test is whether LBGs are embedded in DLAs. If in-situ star formation is occurring in DLAs, we would see it as extended low surface brightness emission around LBGs. We shall use the more accurate photometric redshifts to create a sample of LBGs around which we will look for extended emission in the more sensitive and higher resolution HUDF images. The absence of extended emission would put limits on the SFR density of DLAs associated with LBGs at high redshift. On the other hand, detection of faint emission on scales large compared to the bright LBG cores would indicate the presence of in situ star formation in those DLAs. Such gas would presumably fuel the higher star formation rates present in the LBG cores.

Replication Banding Patterns in Human Chromosomes Detected Using 5-ethynyl-2'-deoxyuridine Incorporation

International Nuclear Information System (INIS)

Hoshi, Osamu; Ushiki, Tatsuo

2011-01-01

A novel technique using the incorporation of 5-ethynyl-2'-deoxyuridine (EdU) into replicating DNA is described for the analysis of replicating banding patterns of human metaphase chromosomes. Human lymphocytes were synchronized with excess thymidine and treated with EdU during the late S phase of the cell cycle. The incorporated EdU was then detected in metaphase chromosomes using Alexa Fluor® 488 azides, through the 1,3-dipolar cycloaddition reaction of organic azides with the terminal acetylene group of EdU. Chromosomes with incorporated EdU showed a banding pattern similar to G-banding of normal human chromosomes. Imaging by atomic force microscopy (AFM) in liquid conditions showed that the structure of the chromosomes was well preserved even after EdU treatment. Comparison between fluorescence microscopy and AFM images of the same chromosome 1 indicated the presence of ridges and grooves in the chromatid arm, features that have been previously reported in relation to G-banding. These results suggest an intimate relationship between EdU-induced replication bands and G- or R-bands in human chromosomes. This technique is thus useful for analyzing the structure of chromosomes in relation to their banding patterns following DNA replication in the S phase

Paper-based inkjet-printed tri-band U-slot monopole antenna for wireless applications

KAUST Repository

Abutarboush, Hattan

2012-01-01

Realization of a U-slot tri-band monopole antenna on a low-cost paper substrate using inkjet-printed technology is presented for the first time. The U-shaped slot is optimized to enhance the bandwidth and to achieve tri-band operation of 1.57, 3.2, and 5 GHz with measured impedance bandwidths of 3.21%, 28.1%, and 36%, respectively. The antenna is fabricated through a metallic nanoparticle ink on a standard commercial paper. Thus, the antenna can be used to cover the GPS, WiMAX, HiperLAN/2, and WLAN. The antenna has a compact size of 12 × 37.3 × 0.44 mm3 , leaving enough space for the driving electronics on the paper substrate. The impedance bandwidth, current distributions, radiation patterns, gain, and efficiency of the antenna have been studied through computer simulations and measurements. © 2002-2011 IEEE.

Distribution of Pa-231 and Ra-226 in rock. An indicator of rock matrix diffusion

International Nuclear Information System (INIS)

Saarinen, L.; Suksi, J.

1995-01-01

Distribution of Ra-226 and Pa-231 in rock has been studied to find signatures that may be attributed to diffusion. The idea of studying these nuclides originated from the need to obtain interpretative support to the findings of U movement in rock. Concentration profiles of Ra-226 and Pa-231 with other U series nuclides were measured across the secondary U accumulations observed in altered rock close to a fracture in the vicinity of U deposit, and in a radioactivity anomaly. (27 refs., 10 figs., 2 tabs.)

Juvenile helium in ancient rocks: II. U-He,K-Ar, Sm-Nd, and Rb-Sr systematics in the Monche Pluton. 3He/4He ratios frozen in uranium-free ultramafic rocks

International Nuclear Information System (INIS)

Tolstikhin, I.N.; Dokuchaeva, V.S.; Kamensky, I.L.; Amelin, Yu.V.

1992-01-01

The important geodynamic parameter, the 3 He/ 4 He ratio in rocks and fluids of the continental crust, is generally decreasing from the mantle values (≅ 10 -5 ) to the radiogenic ratio (≅ 10 -8 ) on the time scale of about 1 Ga or less. However, the ratios, observed in some ancient rocks and minerals, are much higher than the radiogenic value due to a preferential retention of trapped He, when compared with radiogenic helium and/or a low U/ 3 He ratio in a sample. The distribution of He, Ar, Nd, and Sr isotopes, K, Rb, Sm, and U in ultrabasic rocks, in rock-forming minerals, in ores from the 2.49 Ga Monche Pluton, and in basic rocks of the Main Range (the Kola Peninsula) enables one to distinguish sources of the rocks and trapped fluids and outline some peculiarities of petrogenetic and fluid processes. The initial values of var-epsilon Nd (T) = -0.9 ± 0.5 , 87 Sr/ 86 Sr(T) = 0.7021 ± 0.0002, for the 2.49 Ga Monche Pluton are rather similar to these for other layered intrusions of the Baltic Shield. They differ considerably from the model values for the depleted 2.5 Ga old mantle. The observed and rather different sources of 3 He and 4 He as well as the considerable constancy of their ratio in different minerals, separated from both the ultramafic rocks and gabbros, implies: (1) an intensive process of mixing between mantle and crustal components: a melt convection in the chamber may have occurred; (2) the two types of rocks could originate by crystallization differentiation of one and the same melt. Practically all 3 He and 4 He are concentrated in secondary amphiboles; hence the fluid which stimulated the metamorphic process was probably released from the ultramafite-bearing melt

U-shaped Relation between Prestimulus Alpha-band and Poststimulus Gamma-band Power in Temporal Tactile Perception in the Human Somatosensory Cortex.

Science.gov (United States)

Wittenberg, Marc André; Baumgarten, Thomas J; Schnitzler, Alfons; Lange, Joachim

2018-04-01

Neuronal oscillations are a ubiquitous phenomenon in the human nervous system. Alpha-band oscillations (8-12 Hz) have been shown to correlate negatively with attention and performance, whereas gamma-band oscillations (40-150 Hz) correlate positively. Here, we studied the relation between prestimulus alpha-band power and poststimulus gamma-band power in a suprathreshold tactile discrimination task. Participants received two electrical stimuli to their left index finger with different SOAs (0 msec, 100 msec, intermediate SOA, intermediate SOA ± 10 msec). The intermediate SOA was individually determined so that stimulation was bistable, and participants perceived one stimulus in half of the trials and two stimuli in the other half. We measured neuronal activity with magnetoencephalography (MEG). In trials with intermediate SOAs, behavioral performance correlated inversely with prestimulus alpha-band power but did not correlate with poststimulus gamma-band power. Poststimulus gamma-band power was high in trials with low and high prestimulus alpha-band power and low for intermediate prestimulus alpha-band power (i.e., U-shaped). We suggest that prestimulus alpha activity modulates poststimulus gamma activity and subsequent perception: (1) low prestimulus alpha-band power leads to high poststimulus gamma-band power, biasing perception such that two stimuli were perceived; (2) intermediate prestimulus alpha-band power leads to low gamma-band power (interpreted as inefficient stimulus processing), consequently, perception was not biased in either direction; and (3) high prestimulus alpha-band power leads to high poststimulus gamma-band power, biasing perception such that only one stimulus was perceived.

Multiple-band reflective polarization converter using U-shaped metamaterial

International Nuclear Information System (INIS)

Huang, Xiaojun; Yang, Dong; Yang, Helin

2014-01-01

A multiple-band metamaterial reflective polarization converter (RPC) is proposed, which is composed of the dielectric substrate sandwiched with U-shaped metallic patterns and continuous metal film. The proposed U-shaped metamaterial RPC (UMM-RPC) can convert a linearly polarized wave to its cross polarized wave at the three resonant frequencies, which also can convert the linearly polarized wave to circularly polarized wave at other three resonant frequencies. Furthermore, the proposed UMM-RPC can maintain the same conversional direction at the three resonant frequencies when incident on a circularly polarized wave. The simulated and measured results are in agreement in the entire frequency range, and the polarization conversion ratio is over 90% for both linear and circular polarizations. The surface current distributions of the UMM-RPC are discussed to look into the physical mechanism. The proposed UMM-RPC has simple geometry but more operating frequency bands compared to the previous designs and can be used in applications such as antenna radome, remote sensors, and radiometer

Multiple-band reflective polarization converter using U-shaped metamaterial

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiaojun [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); Department of Physics, Kashgar Teachers College, Kashgar 844000 (China); Yang, Dong [College of Physics and Electronics Science, Hubei Normal University, Huangshi 435002 (China); Yang, Helin, E-mail: emyang@mail.ccnu.edu.cn [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China)

2014-03-14

A multiple-band metamaterial reflective polarization converter (RPC) is proposed, which is composed of the dielectric substrate sandwiched with U-shaped metallic patterns and continuous metal film. The proposed U-shaped metamaterial RPC (UMM-RPC) can convert a linearly polarized wave to its cross polarized wave at the three resonant frequencies, which also can convert the linearly polarized wave to circularly polarized wave at other three resonant frequencies. Furthermore, the proposed UMM-RPC can maintain the same conversional direction at the three resonant frequencies when incident on a circularly polarized wave. The simulated and measured results are in agreement in the entire frequency range, and the polarization conversion ratio is over 90% for both linear and circular polarizations. The surface current distributions of the UMM-RPC are discussed to look into the physical mechanism. The proposed UMM-RPC has simple geometry but more operating frequency bands compared to the previous designs and can be used in applications such as antenna radome, remote sensors, and radiometer.

U-Th-Pb systematics of precambrian rocks in the Laramie Mountains, Wyoming

International Nuclear Information System (INIS)

Nkomo, I.T.; Rosholt, J.N.; Dooley, J.R. Jr.

1979-01-01

Uranium, thorium and lead concentrations and the isotopic composition of whole-rock samples of granite from the Laramie Mountains, Wyoming, suggest intrusion of the granite no later than 2530 +- 80 m.y. ago. The uranium in surface samples is present in amounts that are insufficient to account for the observed lead isotopic composition. However, some core samples of heavily fractured rock show an extreme isotopic disequilibrium between 238 U and 206 Pb. Their uranium concentrations are generally far in excess (up to 60%) of average amounts required to support the measured lead-206. Radioactive disequilibrium measurements indicate that large amounts of uranium were gained by these fractured rocks during the last 150,000 years. Lead data on K-feldspar separated from the rocks analyzed suggest that lead has been assimilated by these minerals since time of crystallization. 8 figures, 6 tables

U/Th-isotopes as natural analogues for the mobility of actinides in granitic rocks

International Nuclear Information System (INIS)

Mengel, K.; Gerdes, A.

2001-01-01

The short-lived decay products of 238 U ( 234 U and 230 Th) can be used as natural analogues for actinides in a hard rock repository. Their mobility in the past may serve as a key for understanding actinide migration in the future. For generally old calcites of the HRL Aespoethe age of disturbance of 238 U/ 234 U and 234 U/ 230 Th activity ratios ranges from 30 000 to 436 000 years at degrees of disturbance ranging from 0.5 to 6.7. The results obtained imply that during the past 440 000 years U was mobile throughout the tunnel sections of the HRL Aespoeinvestigated here. For the FL Grimsel, the disequilibrium states of the 234 U/ 238 U and 230 Th/ 234 U activity ratios in fracture minerals (calcites silicates) also imply that the reactions causing isotopic disturbances have occurred within the past 500 000 years. The U/Th-isotope data of both the samples from the HRL Aespoeand the FL Grimsel have in common the mobilization of U in secondary fracture minerals by migrating solutions within the past 500 000 years. As for the question of a final disposal of radioactive waste in granite host rocks, the transport of U - and thus of similarly behaving actinides - in migrating underground solutions can therefore not be ruled out, if suitable hydraulic systems are considered. (orig.)

Rb-Sr ages of Precambrian sedimentary rocks in the U.S.A

International Nuclear Information System (INIS)

Morton, J.P.; Long, L.E.

1982-01-01

Dating of Precambrian sedimentary rocks to determine the age of deposition has not been pursued as diligently in the U.S.A. as in other areas. Ages (which must be regarded as tentative) are summarized for the younger Precambrian stratified rocks of the Grand Canyon (Arizona), the Nonesuch Shale of the Keweenawan Series (Michigan), the Uinta Mountain Group (Utah), and the Belt-Supergroup (Idaho-Montana). An important question of interpretation is whether the ages correspond to times of deposition or of later diagenesis. (Auth.)

The ongoing search for the oldest rock on the Danish island of Bornholm: new U-Pb zircon ages for a quartz-rich xenolith and country rock from the Svaneke Granite

DEFF Research Database (Denmark)

Waight, Tod Earle; Serre, Simon H.; Næsby, Sebastian H.

2017-01-01

Previous geochronological studies on the Danish island of Bornholm have not identified any rocks older than c. 1.46 Ga. New LA-ICP-MS U-Pb zircon ages are presented for a xenolith within, and the country rock gneiss adjacent to, the Svaneke Granite on Bornholm. The xenolith is fine......-grained and quartz-rich and was likely derived from either a quartz-rich sedimentary protolith or a hydrothermally altered felsic volcanic rock. The relatively fine-grained felsic nature of the country rock gneiss and the presence of large zoned feldspars that may represent phenocrysts suggest its protolith may have...... been a felsic volcanic or shallow intrusive rock. A skarn-like inclusion from a nearby locality likely represents an originally carbonate sediment and is consistent with supracrustal rocks being present at least locally. Zircon data from the xenolith define an upper intercept age of 1483 ± 12 Ma (2σ...

Simple calculation of hybridization effects in UTX and U2T2X compounds

International Nuclear Information System (INIS)

Prokes, K.; Brueck, E.; Nakotte, H.; De Chatel, P.F.; De Boer, F.R.

1995-01-01

The band widths of several UTX and U 2 T 2 X compounds (T: transition metal, X: p-metal) are evaluated by means of a tight-binding method. The magnetism in both groups of compounds is governed by the hybridization between U f-states and transition-metal d-states. Comparing the sum of all hybridization effects, we find approximately the same hybridization effects in both groups of compounds. We also observe a decrease of the band width with increasing atomic number Z within a transition-metal series. By comparing the band width with the theoretical critical energies for the f 3 and f 2 configurations, it is in some cases possible to predict whether the ground state is magnetically ordered or not. ((orig.))

LA-ICP-MS U-Pb apatite dating of Lower Cretaceous rocks from teschenite-picrite association in the Silesian Unit (southern Poland

Directory of Open Access Journals (Sweden)

Szopa Krzysztof

2014-08-01

Full Text Available The main products of volcanic activity in the teschenite-picrite association (TPA are shallow, sub-volcanic intrusions, which predominate over extrusive volcanic rocks. They comprise a wide range of intrusive rocks which fall into two main groups: alkaline (teschenite, picrite, syenite, lamprophyre and subalkaline (dolerite. Previous 40Ar/39Ar and 40K/40Ar dating of these rocks in the Polish Outer Western Carpathians, performed on kaersutite, sub-silicic diopside, phlogopite/biotite as well as on whole rock samples has yielded Early Cretaceous ages. Fluorapatite crystals were dated by the U-Pb LA-ICP-MS method to obtain the age of selected magmatic rocks (teschenite, lamprophyre from the Cieszyn igneous province. Apatite-bearing samples from Boguszowice, Puńców and Lipowa yield U-Pb ages of 103± 20 Ma, 119.6 ± 3.2 Ma and 126.5 ± 8.8 Ma, respectively. The weighted average age for all three samples is 117.8 ± 7.3 Ma (MSWD = 2.7. The considerably smaller dispersion in the apatite ages compared to the published amphibole and biotite ages is probably caused by the U-Pb system in apatite being less susceptible to the effects of hydrothermal alternation than the 40Ar/39Ar or 40K/40Ar system in amphibole and/or biotite. Available data suggest that volcanic activity in the Silesian Basin took place from 128 to 103 Ma with the the main magmatic phase constrained to 128-120 Ma.

Distribution of hydrothermally altered rocks in the Reko Diq, Pakistan mineralized area based on spectral analysis of ASTER data

Science.gov (United States)

Rowan, L.C.; Schmidt, R.G.; Mars, J.C.

2006-01-01

The Reko Diq, Pakistan mineralized study area, approximately 10??km in diameter, is underlain by a central zone of hydrothermally altered rocks associated with Cu-Au mineralization. The surrounding country rocks are a variable mixture of unaltered volcanic rocks, fluvial deposits, and eolian quartz sand. Analysis of 15-band Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data of the study area, aided by laboratory spectral reflectance and spectral emittance measurements of field samples, shows that phyllically altered rocks are laterally extensive, and contain localized areas of argillically altered rocks. In the visible through shortwave-infrared (VNIR + SWIR) phyllically altered rocks are characterized by Al-OH absorption in ASTER band 6 because of molecular vibrations in muscovite, whereas argillically altered rocks have an absorption feature in band 5 resulting from alunite. Propylitically altered rocks form a peripheral zone and are present in scattered exposures within the main altered area. Chlorite and muscovite cause distinctive absorption features at 2.33 and 2.20????m, respectively, although less intense 2.33????m absorption is also present in image spectra of country rocks. Important complementary lithologic information was derived by analysis of the spectral emittance data in the 5 thermal-infrared (TIR) bands. Silicified rocks were not distinguished in the 9 VNIR + SWIR bands because of the lack of diagnostic spectral absorption features in quartz in this wavelength region. Quartz-bearing surficial deposits, as well as hydrothermally silicified rocks, were mapped in the TIR bands by using a band 13/band 12 ratio image, which is sensitive to the intensity of the quartz reststrahlen feature. Improved distinction between the quartzose surficial deposits and silicified bedrock was achieved by using matched-filter processing with TIR image spectra for reference. ?? 2006 Elsevier Inc. All rights reserved.

Kent’s Sweden, or what a rock band can tell us about a nation

Directory of Open Access Journals (Sweden)

Johansson, Ola

2013-06-01

Full Text Available Music can communicate a great deal about the culture and society that it comes from. This is the case with the contemporary Swedish rock band Kent, who are not only the most popular band in recent Swedish music history, but also perceived as quintessentially Swedish. Of particular importance to understand this Swedishness is the band’s origin in the city of Eskilstuna, which communicates three interrelated ideas about Sweden: Eskilstuna as an archetypical Swedish small city; the band’s humble beginnings in Eskilstuna illustrates a “class journey” that resonates in Sweden; and Kent’s migration to Stockholm has resulted in an ambivalent relationship with their hometown. The path of Kent’s career has further reinforced the notion of Kent as a Swedish band, particularly as they failed outside the Nordic countries and how their concert choices and collective public persona create associations with Swedishness. Finally, the content of Kent’s music and lyrics are rich with spatial and environmental metaphors that can be conceptualized as four different landscapes representing Sweden: an inner landscape, a public landscape, an urban landscape, and a winter landscape.

Cost-effectiveness of gastric band surgery for overweight but not obese adults with type 2 diabetes in the U.S.

Science.gov (United States)

Wentworth, John M; Dalziel, Kim M; O'Brien, Paul E; Burton, Paul; Shaba, Frackson; Clarke, Philip M; Laiteerapong, Neda; Brown, Wendy A

2017-07-01

To determine the cost-effectiveness of gastric band surgery in overweight but not obese people who receive standard diabetes care. A microsimulation model (United Kingdom Prospective Diabetes Study outcomes model) was used to project diabetes outcomes and costs from a two-year Australian randomized trial of gastric band (GB) surgery in overweight but not obese people (BMI 25 to 30kg/m 2 ) on to a comparable population of U.S. adults from the National Health and Nutrition Examination Survey (N=254). Estimates of cost-effectiveness were calculated based on the incremental cost-effectiveness ratios (ICERs) for different treatment scenarios. Costs were inflated to 2015 U.S. dollar values and an ICER of less than $50,000 per QALY gained was considered cost-effective. The incremental cost-effectiveness ratio for GB surgery at two years exceeded $90,000 per quality-adjusted life year gained but decreased to $52,000, $29,000 and $22,000 when the health benefits of surgery were assumed to endure for 5, 10 and 15 years respectively. The cost-effectiveness of GB surgery was sensitive to utility gained from weight loss and, to a lesser degree, the costs of GB surgery. However, the cost-effectiveness of GB surgery was affected minimally by improvements in HbA1c, systolic blood pressure and cholesterol. GB surgery for overweight but not obese people with T2D appears to be cost-effective in the U.S. setting if weight loss endures for more than five years. Health utility gained from weight loss is a critical input to cost-effectiveness estimates and therefore should be routinely measured in populations undergoing bariatric surgery. Copyright © 2017 Elsevier Inc. All rights reserved.

Palaeointensity determinations and rock magnetic properties on rocks from Izu-Bonin-Mariana fore-arc (IODP Exp. 352).

Science.gov (United States)

Carvallo, Claire; Camps, Pierre; Sager, Will; Poidras, Thierry

2017-04-01

IODP Expedition 352 cored igneous rocks from the Izu-Bonin-Mariana fore-arc crust: Sites U1440 and U1441 recovered Eocene basalts and related rocks whereas Sites U1439 and U1442 recovered Eocene boninites and related rocks. We selected samples from Holes U1439C, U1440B and U1440A for paleointensity measurements. Hysteresis measurements and high and low-temperature magnetization curves show that samples from Hole U1440B undergo magnetochemical changes when heated and are mostly composed of single-domain (SD) or pseudo-single-domain (PSD) titanomaghemite. In contrast, the same measurements show that most selected samples from Holes U1439C and U1442A are thermally stable and are composed of either SD or PSD titanomagnetite with very little titanium content, or SD ferromagnetic grains with a large paramagnetic contribution. Thellier-Thellier paleointensity experiments carried out on U1439C and U1442A samples give a good success rate of 25/60 and Virtual Dipole Moment values between 1.3 and 3.5 ×1022 Am2. Multispecimen paleointensity experiments carried out on 55 samples from Hole U1440B (divided into 4 groups) and 20 from Hole U1439C gave poor quality result, but they seem to indicate a VDM around 4-6 ×1022 Am2 in Hole U1440B fore-arc basalts. These results are in agreement with the low few VDM values previously measured on rocks from Eocene. However, they do not support an inverse relationship between intensity of the field and rate of reversal, since the rate of reversal in Eocene was rather low.

U-Pb age of granitoid rock from the quarry Dubna Skala - Mala Fatra Mts

International Nuclear Information System (INIS)

Cambel, B.; Shcherbak, N.P.; Bartnitsky, E.N.; Stepanyuk, L.M.

1990-01-01

The age of tonalite rock from the quarry Dubna Skala in the Mala Fatra mountains was determined by the U-Pb method. The measurements were carried out at the Institute of Geochemistry and Physics of Minerals in Kiev, USSR. The value measured, 353 m.y., is in a rather good agreement with the data obtained by the Rb-Sr method in core mountain ranges of the Western Carpathians. Nevertheless, in comparison with the Rb-Sr isochronal data from similar rocks and from the same regions, U-Pb geochronologic analyses largely give lower ages. So far, no unique explanation of this fact can be offered; apparently, the geochemical properties of the elements concerned play a major role in this. (author). 1 fig., 1 tab., 30 refs

Band gap of β-PtO2 from first-principles

Directory of Open Access Journals (Sweden)

Yong Yang

2012-06-01

Full Text Available We studied the band gap of β-PtO2 using first-principles calculations based on density functional theory (DFT. The results are obtained within the framework of the generalized gradient approximation (GGA, GGA+U, GW, and the hybrid functional methods. For the different types of calculations, the calculated band gap increases from ∼0.46 eV to 1.80 eV. In particular, the band gap by GW (conventional and self-consistent calculation shows a tendency of converging to ∼1.25 ± 0.05 eV. The effect of on-site Coulomb interaction on the bonding characteristics is also analyzed.

U–Pb, Rb–Sr, and U-series isotope geochemistry of rocks and fracture minerals from the Chalk River Laboratories site, Grenville Province, Ontario, Canada

International Nuclear Information System (INIS)

Neymark, L.A.; Peterman, Z.E.; Moscati, R.J.; Thivierge, R.H.

2013-01-01

Highlights: • AECL evaluates Chalk River Laboratories site as potential nuclear waste repository. • Isotope-geochemical data for rocks and fracture minerals at CRL site are reported. • Zircons from gneiss and granite yielded U–Pb ages of 1472 ± 14 and 1045 ± 6 Ma. • WR Rb–Sr and Pb–Pb systems do not show substantial large-scale isotopic mobility. • U-series and REE data do not support oxidizing conditions at depth in the past 1 Ma. - Abstract: As part of the Geologic Waste Management Facility feasibility study, Atomic Energy of Canada Ltd. (AECL) is evaluating the suitability of the Chalk River Laboratories (CRL) site in Ontario, situated in crystalline rock of the southwestern Grenville Province, for the possible development of an underground repository for low- and intermediate-level nuclear waste. This paper presents petrographic and trace element analyses, U–Pb zircon dating results, and Rb–Sr, U–Pb and U-series isotopic analyses of gneissic drill core samples from the deep CRG-series characterization boreholes at the CRL site. The main rock types intersected in the boreholes include hornblende–biotite (±pyroxene) gneisses of granitic to granodioritic composition, leucocratic granitic gneisses with sparse mafic minerals, and garnet-bearing gneisses with variable amounts of biotite and/or hornblende. The trace element data for whole-rock samples plot in the fields of within-plate, syn-collision, and volcanic arc-type granites in discrimination diagrams used for the tectonic interpretation of granitic rocks. Zircons separated from biotite gneiss and metagranite samples yielded SHRIMP-RG U–Pb ages of 1472 ± 14 (2σ) and 1045 ± 6 Ma, respectively, in very good agreement with widespread Early Mesoproterozoic plutonic ages and Ottawan orogeny ages in the Central Gneiss Belt. The Rb–Sr, U–Pb, and Pb–Pb whole-rock errorchron apparent ages of most of the CRL gneiss samples are consistent with zircon U–Pb age and do not indicate

Alteration of submarine volcanic rocks in oxygenated Archean oceans

Science.gov (United States)

Ohmoto, H.; Bevacqua, D.; Watanabe, Y.

2009-12-01

Most submarine volcanic rocks, including basalts in diverging plate boundaries and andesites/dacites in converging plate boundaries, have been altered by low-temperature seawater and/or hydrothermal fluids (up to ~400°C) under deep oceans; the hydrothermal fluids evolved from shallow/deep circulations of seawater through the underlying hot igneous rocks. Volcanogenic massive sulfide deposits (VMSDs) and banded iron formations (BIFs) were formed by mixing of submarine hydrothermal fluids with local seawater. Therefore, the behaviors of various elements, especially of redox-sensitive elements, in altered submarine volcanic rocks, VMSDs and BIFs can be used to decipher the chemical evolution of the oceans and atmosphere. We have investigated the mineralogy and geochemistry of >500 samples of basalts from a 260m-long drill core section of Hole #1 of the Archean Biosphere Drilling Project (ABDP #1) in the Pilbara Craton, Western Australia. The core section is comprised of ~160 m thick Marble Bar Chert/Jasper Unit (3.46 Ga) and underlying, inter-bedded, and overlying submarine basalts. Losses/gains of 65 elements were quantitatively evaluated on the basis of their concentration ratios against the least mobile elements (Ti, Zr and Nb). We have recognized that mineralogical and geochemical characteristics of many of these samples are essentially the same as those of hydrothermally-altered modern submarine basalts and also those of altered volcanic rocks that underlie Phanerozoic VMSDs. The similarities include, but are not restricted to: (1) the alteration mineralogy (chlorite ± sericite ± pyrophyllite ± carbonates ± hematite ± pyrite ± rutile); (2) the characteristics of whole-rock δ18O and δ34S values; (3) the ranges of depletion and enrichment of Si, Al, Mg, Ca, K, Na, Fe, Mn, and P; (4) the enrichment of Ba (as sulfate); (5) the increases in Fe3+/Fe2+ ratios; (6) the enrichment of U; (7) the depletion of Cr; and (8) the negative Ce anomalies. Literature data

Rectangular waveguide-to-coplanar waveguide transitions at U-band using e-plane probe and wire bonding

DEFF Research Database (Denmark)

Dong, Yunfeng; Johansen, Tom Keinicke; Zhurbenko, Vitaliy

2016-01-01

This paper presents rectangular waveguide-to-coplanar waveguide (CPW) transitions at U-band (40–60 GHz) using E-plane probe and wire bonding. The designs of CPWs based on quartz substrate with and without aluminum cover are explained. The single and double layer rectangular waveguide-to-CPW trans......This paper presents rectangular waveguide-to-coplanar waveguide (CPW) transitions at U-band (40–60 GHz) using E-plane probe and wire bonding. The designs of CPWs based on quartz substrate with and without aluminum cover are explained. The single and double layer rectangular waveguide......-to-CPW transitions using E-plane probe and wire bonding are designed. The proposed rectangular waveguide-to-CPW transition using wire bonding can provide 10 GHz bandwidth at U-band and does not require extra CPWs or connections between CPWs and chips. A single layer rectangular waveguide-to-CPW transition using E......-plane probe with aluminum package has been fabricated and measured to validate the proposed transitions. To the authors' best knowledge, this is the first time that a wire bonding is used as a probe for rectangular waveguide-to-CPW transition at U-band....

Paleozoic age of high-pressure metamorphic rocks of the Dakh salient, North-Western Caucasus: results of U-Pb-geochronological study

International Nuclear Information System (INIS)

Somin, M.L.; Levchenkov, O.A.; Kotov, A.B.; Makeev, A.F.; Komarov, A.N.; Ro, N.I.; Lavrishchev, V.A.; Lebedev, V.A.

2007-01-01

U-Pb geochronological studies of an ancient component of the Dakh salient, i.e. metaaplites, which are vein fine-grained rocks made up by albite, microcline, quartz and potash mica, were made. Besides, K-Ar dating of granodiorites breaking through metamorphic rocks was conducted. U-Pb dating of accessory zircons (353 mln. years) defines the lower age boundary of the Dakh salient rock metamorphism. Its upper boundary was identified by K-Ar dating (301 ± 10 mln. years) of hornfels blende of nonmetamophized granodiorites [ru

Hot dry rock geothermal energy for U.S. electric utilities. Draft final report

Energy Technology Data Exchange (ETDEWEB)

1993-06-01

In order to bring an electric utility component into the study of hot dry rock geothermal energy called for in the Energy Policy Act of 1992 (EPAct), EPRI organized a one-day conference in Philadelphia on January 14,1993. The conference was planned as the first day of a two-day sequence, by coordinating with the U.S. Geological Survey (USGS) and the U.S. Department of Energy (DOE). These two federal agencies were charged under EPAct with the development of a report on the potential for hot dry rock geothermal energy production in the US, especially the eastern US. The USGS was given lead responsibility for a report to be done in association with DOE. The EPRI conference emphasized first the status of technology development and testing in the U.S. and abroad, i.e., in western Europe, Russia and Japan. The conference went on to address the extent of knowledge regarding the resource base in the US, especially in the eastern half of the country, and then to address some practical business aspects of organizing projects or industries that could bring these resources into use, either for thermal applications or for electric power generation.

Activity of radioactive inclusions in igneous rocks

Energy Technology Data Exchange (ETDEWEB)

Coppens, R

1949-01-10

It has been shown by Hee (Compt. rend. 227, 356(1948)) that the radioactivity of igneous rocks is traceable to radioactive inclusions. The present author used the photoemulsion method for the determination of U and Th content of rocks, by counting ..cap alpha.. tracks produced by such inclusions, per cm/sup 2/ and per sec. Rock powder was placed upon Ilford C/sub 2/ emulsions, the exposition time varying between 7 and 18 days. In most cases, prolonged trajectories meet upon a well delineated small surface corresponding to the inclusions. The formula used is that given by I. Curie (J. Phys., (1946) Nov) which, after substitution of constants, has the form N = 8.4KC(U) + 2.5KC(Th); here N is the number of trajectories, C(U) and C(Th) are the concentrations of U and Th, and K is a coefficient varying between 14 for granite and 31 for uranium oxide and thorite. Using as a second equation C(Th) = 2.5C(U), the concentrations C(Th) and C(U) can be determined. The method was tested on seven samples of granitic sand and micaschist from Brittany. Their average contents was found to be about 10% U and 22% Th, with approximations of about 20%.

Microbial Leaching of Some Valuable Elements From Egyptian Phosphate Rock

International Nuclear Information System (INIS)

Kamal, H.M.; Hassanein, R.A.; Mahdy, H.M.A.; Mahmoud, K.F.; Abouzeid, M.A.

2012-01-01

Four phosphate rock samples representing different phosphate mineralization modes in Egypt were selected from Abu Tartar, Nile valley and Red sea areas. Factors affecting the phosphate rock solubilization and some of the contained valuable elements by Aspergillus niger, Penicillium sp. and Pseudomonas fluorescence, were studied with especial orientation towards the completion of phosphate rock samples solubilization especially die low grade one. Effect of nitrogen source type on leaching efficiency by Aspergillus niger when two nitrogen sources on the phosphate bioleaching efficiency, it is clear that the ammonium chloride is more favorable as nitrogen source than sodium nitrate in the bioleaching of phosphate rocks. When Aspergillus niger was applied under die following conditions: 50 g/1 of sucrose as a carbon source, 0.1 N of ammonium chloride as a nitrogen source, 10 days incubation period, 0.5% solid: liquid ratio for P 2 O 5 and 5% for U and REE and - 270 mesh of grain size. The optimum leaching of P 2 O 5 , U and REE from phosphate rock samples reached (23.27%, 17.4%, 11.4%, respectively), while at -60 mesh they reached to 16.58%, 28.9%, 30.2% respectively. The optimum conditions for the maximal leaching efficiencies of P 2 O 5 , U and REE when applying the Penicillium sp. from the phosphate rock samples were: 100 g/1 of sucrose as a carbon source for P 2 O 5 and U and 10 g/1 for REE, 7,15 and 10 days incubation period for P 2 O 5 , U and REE, respectively, 0.5% solid: liquid ratio for P 2 O 5 and 5% for U and REE. Finally, the application of phosphate rock samples grinded to -270 mesh of grain size for P 2 O 5 and (-60 to -140) for U and REE. The studied leaching efficiency of P 2 O 5 , U and REE gave at -270 mesh 33.66%, 24.3%, 15.9% respectively, while at -60 mesh they gave 33.76%, 26.7%, 17.8% and at -140 mesh gave 31.32%, 27.9%, 17.6%, respectively.The optimum conditions for the P 2 O 5 leaching efficiency when applying the Pseudomonas fluorescence were

Median and ulnar neuropathies in U.S. Army Medical Command Band members.

Science.gov (United States)

Shaffer, Scott W; Koreerat, Nicholas R; Gordon, Lindsay B; Santillo, Douglas R; Moore, Josef H; Greathouse, David G

2013-12-01

Musicians have been reported as having a high prevalence of upper-extremity musculoskeletal disorders, including carpal tunnel syndrome. The purpose of this study was to determine the presence of median and ulnar neuropathies in U.S. Army Medical Command (MEDCOM) Band members at Fort Sam Houston, Texas. Thirty-five MEDCOM Band members (30 males, 5 females) volunteered to participate. There were 33 right-handed musicians, and the mean length of time in the MEDCOM Band was 12.2 yrs (range, 1-30 yrs). Subjects completed a history form, were interviewed, and underwent a physical examination of the cervical spine and bilateral upper extremities. Nerve conduction studies of the bilateral median and ulnar nerves were performed. Electrophysiological variables served as the reference standard for median and ulnar neuropathy and included distal sensory latencies, distal motor latencies, amplitudes, conduction velocities, and comparison study latencies. Ten of the 35 subjects (29%) presented with abnormal electrophysiologic values suggestive of an upper extremity mononeuropathy. Nine of the subjects had abnormal median nerve electrophysiologic values at or distal to the wrist; 2 had bilateral abnormal values. One had an abnormal ulnar nerve electrophysiologic assessment at the elbow. Nine of these 10 subjects had clinical examination findings consistent with the electrophysiological findings. The prevalence of mononeuropathies in this sample of band members is similar to that found in previous research involving civilian musicians (20-36%) and far exceeds that reported in the general population. Prospective research investigating screening, examination items, and injury prevention measures in musicians appears to be warranted.

Suitable reverberation time for halls for rock and pop music

DEFF Research Database (Denmark)

Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

2010-01-01

The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of popular music, including rock and pop. Objective measurements were made of the acoustics of 20 rock music venues in Denmark....... The best-rated halls in the study have reverberation times that are approximately frequency independent from 0.6 to 1.2 s for hall volumes from 1000 to 6000 m3. The worst rated halls in the study had significantly higher reverberation times in the 63 and 125 Hz bands. Since most audiences at rock concerts...... are standing, absorption coefficients were measured with a standing audience from 63 Hz to 4 kHz. These measurements showed that a standing audience absorbs about five times as much energy in mid-/high-frequency bands as in low-frequency bands....

Spin-polarized investigation of ferromagnetism on magnetic semiconductors MnxCa1−xS in the rock-salt phase

International Nuclear Information System (INIS)

Choutri, H.; Ghebouli, M.A.; Ghebouli, B.; Bouarissa, N.; Uçgun, E.; Ocak, H.Y.

2014-01-01

The structural, elastic, electronic and magnetic properties of the diluted magnetic semiconductors Mn x Ca 1−x S in the rock-salt phase have been investigated using first-principles calculations with both LDA and LDA + U functional. Features such as lattice constant, bulk modulus, elastic constants, spin-polarized band structure, total and local densities of states have been computed. We predict the values of the exchange constants and the band edge spin splitting of the valence and conduction bands. The hybridization between S-3p and Mn-3d produces small local magnetic moment on the nonmagnetic Ca and S sites. The ferromagnetism is induced due to the exchange splitting of S-3p and Mn-3d hybridized bands. The total magnetic moment per Mn of Mn x Ca 1−x S is 4.4μ B and 4.5μ B for LDA and LDA + U functional and is independent of the Mn concentration. The unfilled Mn-3d levels reduce the local magnetic moment of Mn from its free space charge value of 5μ B –4.4μ B and4.5μ B for LDA and LDA + U functional due to 3p–3d hybridization. - Highlights: • Fundamental properties of magnetic semiconductors Mn x Ca 1−x S. • Rock-salt phase of Mn x Ca 1−x S. • Magnetic properties of the diluted magnetic semiconductors Mn x Ca 1−x S. • The use of LDA + U functionals

The transport characteristics of {sup 238}U, {sup 232}Th, {sup 226}Ra, and {sup 40}K in the production cycle of phosphate rock

Energy Technology Data Exchange (ETDEWEB)

Jung, Yoon Hee; Lim, Jong Myoung; Ji, Young Yong; Chung, Kun Ho; Kang, Mun Ja [Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2017-03-15

Phosphate rock and its by-product are widely used in various industries to produce phosphoric acid, gypsum, gypsum board, and fertilizer. Owing to its high level of natural radioactive nuclides (e.g., 238U and 226Ra), the radiological safety of workers who work with phosphate rock should be systematically managed. In this study, 238U, 232Th, 226Ra, and 40K levels were measured to analyze the transport characteristics of these radionuclides in the production cycle of phosphate rock. Energy dispersive X-ray fluorescence and gamma spectrometry were used to determine the activity of 238U, 232Th, 226Ra, and 40K. To evaluate the extent of secular disequilibrium, the analytical results were compared using statistical methods. Finally, the distribution of radioactivity across different stages of the phosphate rock production cycle was evaluated. The concentration ratios of 226Ra and 238U in phosphate rock were close to 1.0, while those found in gypsum and fertilizer were extremely different, reflecting disequilibrium after the chemical reaction process. The nuclide with the highest activity level in the production cycle of phosphate rock was 40K, and the median 40K activity was 8.972 Bq·g−1 and 1.496 Bq·g−1, respectively. For the 238U series, the activity of 238U and 226Ra was greatest in phosphate rock, and the distribution of activity values clearly showed the transport characteristics of the radionuclides, both for the byproducts of the decay sequences and for their final products. Although the activity of 40K in k-related fertilizer was relatively high, it made a relatively low contribution to the total radiological effect. However, the activity levels of 226Ra and 238U in phosphate rock were found to be relatively high, near the upper end of the acceptable limits. Therefore, it is necessary to systematically manage the radiological safety of workers engaged in phosphate rock processing.

Trace element analysis of silicate rocks by XRF. Pt. 2

International Nuclear Information System (INIS)

Orihashi, Yuji; Yuhara, Masaki; Kagami, Hiroo; Honma, Hiroji

1993-01-01

Quantitative X-ray fluorescence analysis of six trace elements (Ce, Ba, Ga, Co, Cr, V) in silicate rocks has been investigated, using pressed powder pellets. Ga analysis was performed using a Cr tube, whereas a Au tube was used for the remaining five elements. Corrections were made for the interference of BaKα on CeKα, FeKβ on CoKα, CrKα on VKβ and VKα on TiKβ. Mass absorption functions were estimated from background intensities at 2θ=35.5deg and that of FeKα at wavelengths longer than the iron absorption edge for a Au tube, and from the value of net intensity/background one for a Cr tube. Calibration lines were constructed using twenty-four U.S. Geological Survey and Geological Survey of Japan igneous rock reference samples. For each line, the correction coefficient is greater than 0.993 except for Ga and Ce (>0.985), indicating that the correction and calibration procedures are appropriate for accurate analysis over a wide compositional range. Analytical results for igneous, sedimentary and metamorphic reference samples (U. S. Geological Survey, Institute of Geophysical and Geochemical Exploration, South-African Bureau of Standards) accord well with recommended or proposed values, respectively. The results of this study and those of Orihashi et al. (1993) show Ce, Ba, Nb, Zr, Y, Sr, Rb, Th, Ga, Zn, Cu, Ni, Co, Cr and V in silicate rocks can be quantitatively determined by XRF at ISEI. (author)

Relict zircon U-Pb age and O isotope evidence for reworking of Neoproterozoic crustal rocks in the origin of Triassic S-type granites in South China

Science.gov (United States)

Gao, Peng; Zheng, Yong-Fei; Chen, Yi-Xiang; Zhao, Zi-Fu; Xia, Xiao-Ping

2018-02-01

Granites derived from partial melting of sedimentary rocks are generally characterized by high δ18O values and abundant relict zircons. Such relict zircons are valuable in tracing the source rocks of granites and the history of crustal anatexis. Here we report in-situ U-Pb ages, O isotopes and trace elements in zircons from Triassic granites in the Zhuguangshan and Jiuzhou regions, which are located in the Nanling Range and the Darongshan area, respectively, in South China. Zircon U-Pb dating yields magma crystallization ages of 236 ± 2 Ma for the Zhuguangshan granites and 246 ± 2 Ma to 252 ± 3 Ma for the Jiuzhou granites. The Triassic syn-magmatic zircons are characterized by high δ18O values of 10.1-11.9‰ in Zhuguangshan and 8.5-13.5‰ in Jiuzhou. The relict zircons show a wide range of U-Pb ages from 315 to 2185 Ma in Zhuguangshan and from 304 to 3121 Ma in Jiuzhou. Nevertheless, a dominant age peak of 700-1000 Ma is prominent in both occurrences, demonstrating that their source rocks were dominated by detrital sediments weathered from Neoproterozoic magmatic rocks. Taking previous results for regional granites together, Neoproterozoic relict zircons show δ18O values in a small range from 5 to 8‰ for the Nanling granites but a large range from 5 to 11‰ for the Darongshan granites. In addition, relict zircons of Paleozoic U-Pb age occur in the two granitic plutons. They exhibit consistently high δ18O values similar to the Triassic syn-magmatic zircons in the host granites. These Paleozoic relict zircons are interpreted as the peritectic product during transient melting of the metasedimentary rocks in response to the intracontinental orogenesis in South China. Therefore, the relict zircons of Neoproterozoic age are directly inherited from the source rocks of S-type granites, and those of Paleozoic age record the transient melting of metasedimentary rocks before intensive melting for granitic magmatism in the Triassic.

Estilo e autenticidade em bandas de rock de Florianópolis (SC Style and authencity of Florianópolis rock bands

Directory of Open Access Journals (Sweden)

Tatyana de Alencar Jacques

2008-08-01

Full Text Available Partindo de uma etnografia do rock independente da cidade de Florianópolis, SC, este artigo trata das concepções artísticas e visões de mundo dos músicos que integram este universo, tendo como foco a constituição dos estilos de suas bandas e seu processo de composição musical. A elaboração destes estilos age no sentido de configurar um território simbólico demarcado por uma percepção de mundo hedonista, que se opõe à racionalização da sociedade moderna e que é expressa não por um discurso verbal articulado, mas por uma forma específica de criar música.Based on an ethnography carried out in the city of Florianopolis, of the state of Santa Catarina, in Brazil, this paper discusses the artistic conceptions and world views of independent rock musicians. It focuses on the creation of their band styles and their music composing process. The elaboration of these styles shape a symbolic territory delimited by a hedonistic world perception in contrast to modern society's rationalism. Their world perception is expressed not by verbal articulated discourse but by a specific way of creating music.

Carboniferous-Permian volcanic evolution in Central Europe-U/Pb ages of volcanic rocks in Saxony (Germany) and northern Bohemia (Czech Republic)

Czech Academy of Sciences Publication Activity Database

Hoffmann, U.; Breitkreuz, Ch.; Breiter, Karel; Sergeev, S.; Stanek, K.; Tichomirowa, M.

2013-01-01

Roč. 102, č. 1 (2013), s. 73-99 ISSN 1437-3254 Institutional support: RVO:67985831 Keywords : pyroclastic rocks * dykes * stratigraphy * SHRIMP U/Pb ages * Pb/Pb single zircon age * Variscides Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.084, year: 2013

Petrology and geochemistry of the ~2.9 Ga Itilliarsuk banded iron formation and associated supracrustal rocks, West Greenland

DEFF Research Database (Denmark)

Haugaard, Rasmus; Frei, Robert; Stendal, Henrik

2013-01-01

unconformably on a basement of tonalite–trondhjemite–granodiorite (TTG) lithologies. Felsic metagreywackes, meta-semipelites and thinly bedded ferruginous shales were identified intercalated with the Itilliarsuk BIF. Other associated rocks include metapelites, acidic metavolcanics and metagabbroic sills.......29. The associated supracrustal rocks in the study area have significantly higher, positive ɛNd(i) values. The 143Nd/144Nd in the Itilliarsuk BIF, therefore, contrasts world BIFs by exhibiting radiogenic, positive ɛNd(i) values in shallow seawaters where the REY's were controlled by a local, depleted continental...... crust, whereas the negative ɛNd(i) values found in the iron-rich layers suggest that the submarine hydrothermal source was influenced by an enriched mantle, possibly an older subcontinental lithospheric segment. The felsic metagreywackes are immature, first-cycle (SiO2/Al2O3 ∼ 4.4, [La/Yb >> 1]CHON...

Uranium endowments in phosphate rock

Energy Technology Data Exchange (ETDEWEB)

Ulrich, Andrea E., E-mail: andrea.ulrich@env.ethz.ch [Institute for Environmental Decisions (IED), Natural and Social Science Interface, ETH Zurich Universitässtrasse 22, 8092 Zurich (Switzerland); Institute for Agricultural Sciences, Plant Nutrition, ETH Zurich, Eschikon 33, 8315 Lindau (Switzerland); Schnug, Ewald, E-mail: e.schnug@tu-braunschweig.de [Department of Life Sciences, Technical University of Braunschweig, Pockelsstraße 14, D-38106 Braunschweig (Germany); Prasser, Horst-Michael, E-mail: prasser@lke.mavt.ethz.ch [Institute of Energy Technology, Laboratory of Nuclear Energy Systems, ETH Zurich, Sonneggstrasse 3, 8092 Zurich (Switzerland); Frossard, Emmanuel, E-mail: emmanuel.frossard@usys.ethz.ch [Institute for Agricultural Sciences, Plant Nutrition, ETH Zurich, Eschikon 33, 8315 Lindau (Switzerland)

2014-04-01

This study seeks to identify and specify the components that make up the prospects of U recovery from phosphate rock. A systems approach is taken. The assessment includes i) reviewing past recovery experience and lessons learned; ii) identifying factors that determine recovery; and iii) establishing a contemporary evaluation of U endowments in phosphate rock reserves, as well as the available and recoverable amounts from phosphate rock and phosphoric acid production. We find that in the past, recovery did not fulfill its potential and that the breakup of the Soviet Union worsened then-favorable recovery market conditions in the 1990s. We find that an estimated 5.7 million tU may be recoverable from phosphate rock reserves. In 2010, the recoverable tU from phosphate rock and phosphoric acid production may have been 15,000 tU and 11,000 tU, respectively. This could have filled the world U supply-demand gap for nuclear energy production. The results suggest that the U.S., Morocco, Tunisia, and Russia would be particularly well-suited to recover U, taking infrastructural considerations into account. We demonstrate future research needs, as well as sustainability orientations. We conclude that in order to promote investment and production, it seems necessary to establish long-term contracts at guaranteed prices, ensuring profitability for phosphoric acid producers. - Highlights: • We identify components that underlie the recovery of uranium from phosphate rock. • We estimate that 11,000 tU may have been recoverable from phosphoric acid in 2010. • Recovery is a resource conservation and environmental pollution control strategy. • To ensure investment in recovery technology, profitability needs to be secured.

Uranium endowments in phosphate rock

International Nuclear Information System (INIS)

Ulrich, Andrea E.; Schnug, Ewald; Prasser, Horst-Michael; Frossard, Emmanuel

2014-01-01

This study seeks to identify and specify the components that make up the prospects of U recovery from phosphate rock. A systems approach is taken. The assessment includes i) reviewing past recovery experience and lessons learned; ii) identifying factors that determine recovery; and iii) establishing a contemporary evaluation of U endowments in phosphate rock reserves, as well as the available and recoverable amounts from phosphate rock and phosphoric acid production. We find that in the past, recovery did not fulfill its potential and that the breakup of the Soviet Union worsened then-favorable recovery market conditions in the 1990s. We find that an estimated 5.7 million tU may be recoverable from phosphate rock reserves. In 2010, the recoverable tU from phosphate rock and phosphoric acid production may have been 15,000 tU and 11,000 tU, respectively. This could have filled the world U supply-demand gap for nuclear energy production. The results suggest that the U.S., Morocco, Tunisia, and Russia would be particularly well-suited to recover U, taking infrastructural considerations into account. We demonstrate future research needs, as well as sustainability orientations. We conclude that in order to promote investment and production, it seems necessary to establish long-term contracts at guaranteed prices, ensuring profitability for phosphoric acid producers. - Highlights: • We identify components that underlie the recovery of uranium from phosphate rock. • We estimate that 11,000 tU may have been recoverable from phosphoric acid in 2010. • Recovery is a resource conservation and environmental pollution control strategy. • To ensure investment in recovery technology, profitability needs to be secured

Properties of U3Si2-Al dispersion fuel element and its application

International Nuclear Information System (INIS)

Yin Changgeng

2001-01-01

The properties of U 3 Si 2 fuel and U 3 Si 2 -Al dispersion fuel element are introduced, which include U-loading; the banding quality, U-homogeneity and 'dog-bone' phenomenon, the minimum thickness of cladding and the corrosion performances. The fabrication technique of fuel elements, NDT for fuel plates, assemble technique of fuel elements and the application of U 3 Si 2 -Al dispersion fuel elements in the world are introduced

Nd isotopes, U-Pb single grain and SHRIMP zircon ages from basement rocks of the Tocantin Province

International Nuclear Information System (INIS)

Fuck, R.A.; Dantas, E.L.; Pimentel, M.M.; Junges, S.L.; Moraes, R

2001-01-01

Large areas of the northern part of the Brasilia Belt, Tocantins Province, central Brazil, are underlain by basement granite-gneiss terrain and associated volcano-sedimentary sequences, as well as felsic and mafic-ultramafic intrusions. The basement rocks are covered by the late Paleoproterozoic-Mesoproterozoic rift-related Arai and Natividade groups and intruded by 1.77 to 1.58 Ga an orogenic granites of the Goias Tin Province (Pimentel and Botelho, 2001). To the southwest they are un conformably overlain by the low-grade late Proterozoic Paranoa Group, whereas to the east they are in faulted contact with the Neoproterozoic Bambui Group at the western edge of the Sao Francisco Craton. To the north they are covered by Phanerozoic sediments of the Parnaiba and Sanfranciscana basins. Despite their large extension, granite-gneiss and associated supracrustals of SE Tocantins and NE Goias are still poorly known. Previous regional Rb-Sr and K-Ar isotopic studies indicated dominant early Proterozoic ages and late Proterozoic cooling ages (Hasui, et al. 1980, Fernandes et al. 1982). More detailed studies in the Almas-Dianopolis area (Costa, 1984) came up with similar results, although the region was interpreted as underlain by Archean granite-greenstone terrain, following previous suggestions by Costa et al. (1976). Recent work recognized the presence of two suites of deformed granitoids (Cruz and Kuyumjian, 1996, 1998). The oldest suite intruded the supracrustals and comprises hornblende-bearing tonalite gneiss, with minor trondhjemite, granodiorite, and quartz diorite. The younger suite comprises oval shaped biotite-bearing tonalite, trondhjemite, and granodiorite intrusions. Both suites display low-K calc-alkaline affinity, the younger being more Al-rich. Both are interpreted as TTG suites and were dated at 2,2 Ga using U-Pb SHRIMP (Cruz et al 2000). In the Porto Nacional area, Gorayeb et al. (2000) determined single zircon Pb-evaporation ages of 2.15 Ga in granulites

Radiogeochemical characteristic of rocks of the Crimea peninsula and some principles of sedimentation

International Nuclear Information System (INIS)

Gherasimov, Yu.G.

1983-01-01

Radiogeochemical mapping with rock sampling of profiles, crossing all main structural facies zones of the Crimea peninsula was conducted. 1000 samples were taken. Uranium determination in samples was performed by fluorescence method (2 g/t threshold sensitivity). The distributions of U and Th background contents in rocks of the Crimea were tabulated. Maps of sampling of geological formations and distribution of U and Th background contents in rocks are given. It is shown that radioelement content in Crimea rocks is for the most part lower than clark one: 1.3-2.1 g/t contents prevail for U, Th contents don't exceed 12 g/t. Closeness of some radiogeochemical parameters points to the formation of terrigenous Crimea rocks due to removal of the material from the Ukrainian shield. Reworking of initial terrigenous material by hypergene processes led to U and Th separation, as well as to enrichment of younger sedimentary rocks with uranium

Peptide substrates for Rho-associated kinase 2 (Rho-kinase 2/ROCK2.

Directory of Open Access Journals (Sweden)

Jeong-Hun Kang

Full Text Available Peptide substrates sensitive for a certain protein kinase could be important for new-drug development and to understand the mechanism of diseases. Rho-associated kinase (Rho-kinase/ROCK is a serine/threonine kinase, and plays an important part in cardiovascular disease, migration and invasion of tumor cells, and in neurological disorders. The purpose of this study was to find substrates with high affinity and sensitivity for ROCK2. We synthesized 136 peptide substrates from protein substrates for ROCK2 with different lengths and charged peptides. Incorporation of (32P [counts per minute (CPM] for each peptide substrate was determined by the radiolabel assay using [γ-(32P]ATP. When the top five peptide substrates showing high CPMs (R4, R22, R133, R134, and R135 were phosphorylated by other enzymes (PKA, PKCα, and ERK1, R22, R133, and R135 displayed the highest CPM level for ROCK2 compared with other enzymes, whereas R4 and R134 showed similar CPM levels for ROCK2 and PKCα. We hypothesize that R22, R133, and R135 can be useful peptide substrates for ROCK2.

Potassium, uranium, thorium radiogenic heat contribution to heat flow in the Precambrian and younger silicic rocks of the Zuni and Florida Mountains, New Mexico (U.S.A.)

International Nuclear Information System (INIS)

Brookins, D.G.

1982-01-01

High heat flow in the Zuni Mountains, New Mexico, U.S.A., has been explained by the possible presence of a buried felsic pluton. Alternately, high K, U, Th abundances have been proposed to account for part of the high heat flow. The mean radiogenic heat contricution for 60 samples of Precambrian core rocks is 7.23 μcal/gm-yr, which is slightly higher than the average for western U.S.A. granitic rocks and significantly higher than the average for continental 'crust'; hence, the K, U, Th radiogenic contribution from Precambrian rocks to the overall heat flow is significant. Radiogenic K, U, Th heat for 32 samples for the Florida Mountains, New Mexico, U.S.A., yields a lower mean of 5.46 μcal/gm-yr. This value is somewhat anomalous in that the predominantly syenitic rocks commonly yield higher values. Furthermore, heat flow is higher in areas distant from the Floridas and the radiogenic heat contribution is considered small. (orig.)

SHRIMP zircon U-Pb age and its significances of volcanic rocks from banshi basin in south jiangxi province

International Nuclear Information System (INIS)

Wang Baofeng; Wu Jianhua

2011-01-01

SHRIMP zircon U-Pb dating is applied to geochronological study for tuff of original Jilongzhang formation and rhyolite of original Banshi formation in Banshi basin, located in the Sannan (Longnan, Dingnan, Quannan) -Xunwu volcanic rocks belts in the south of Jiangxi. The result shows that zircon SHRIMP U-Pb age of the tuff is (142.5 ± 1.3) Ma and the age of the rhyolite is (131.4 ± 1.3) Ma. According to the latest international stratigraphic chart, the boundary between Jurassic and Cretaceous is (145.4 ± 4.0) Ma. So original Jilongzhang Formation and original Banshi Formation in Banshi basin were formed during early Early Cretaceous. The volcanic series in Banshi basin belongs to only one volcanic cycle. The features of the rock associations consistent with Wuyi group on the Xiajiang-Guangfeng volcanic rocks belts in the north of Jiangxi, so original Jilongzhang formation falls under E'huling formation and original Banshi formation falls under Shixi formation. (authors)

Band structure and Fermi surface of UPd2Al3 studied by angle-resolved photoemission spectroscopy

International Nuclear Information System (INIS)

Fujimori, Shin-ichi; Saitoh, Yuji; Okane, Tetsuo; Yamagami, Hiroshi; Fujimori, Atsushi; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika

2007-01-01

We have observed the band structure and Fermi surfaces of the heavy Fermion superconductor UPd 2 Al 3 by angle-resolved photoemission experiments in the soft X-ray region. We observed renormalized quasi-particle bands in the vicinity of the Fermi level and strongly dispersive bands on the higher binding energy side. Our observation suggests that the structure previously assigned to contributions from localized states in the U 5f spectrum has strong energy dispersions

CERN’s Summer of Rock

CERN Multimedia

Katarina Anthony

2015-01-01

When a rock star visits CERN, they don’t just bring their entourage with them. Along for the ride are legions of fans across the world – many of whom may not be the typical CERN audience. In July alone, four big acts paid CERN a visit, sharing their experience with the world: Scorpions, The Script, Kings of Leon and Patti Smith.   @TheScript tweeted: #paleofestival we had the best time! Big love. #CERN (Image: Twitter).   It all started with the Scorpions, the classic rock band whose “Wind of Change” became an anthem in the early 1990s. On 19 July, the band braved the 35-degree heat to tour the CERN site on foot – visiting the Synchrocyclotron and the new Microcosm exhibition. The rockers were very enthusiastic about the research carried out at CERN, and talked about returning in the autumn during their next tour stop. The Scorpions visit Microcosm. Two days later, The Script rolled in. This Irish pop-rock band has been hittin...

Behaviour of {sup 238}U, {sup 234}U, {sup 228}Ra and {sup 226}Ra in rock alterations: study of Morungaba granitoids, SP-Brazil and ground water in its fractures; Comportamento de {sup 238}U, {sup 234}U, {sup 228}Ra e {sup 226}Ra na alteracao de rochas: estudo dos granitoides de Morungaba (SP) e aguas subterraneas de suas fraturas

Energy Technology Data Exchange (ETDEWEB)

Santos, Rosana N. dos [Pontificia Univ. Catolica de Sao Paulo, SP (Brazil). Dept. de Fisica]. E-mail: rosana@pucsp.br; Marques, Leila S. [Sao Paulo Univ., SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas. Dept. de Geofisica]. E-mail: leila@iag.usp.br

2005-07-01

This work presents the first results obtained on the investigation of the behavior of uranium and radium radioisotopes in the processes of weathering and rock-water interaction of Morungaba granitoids belonging to Meridional Pluton (Valinhos Town-SP-Brazil). Specific activities of {sup 238}U, {sup 234}U, {sup 228}Ra and {sup 226}Ra were determined in non altered granitoids (Group A), as well as in those affected by different degrees of weathering (Groups B, C and D). The uranium specific activities were determined by alpha spectrometry method, whereas for the determination of radium isotopes high resolution gamma-ray spectrometry technique was employed. The data indicate that {sup 238}U and {sup 234}U are in radioactive equilibrium in the fresh analyzed granitoids, but show a slight depletion of {sup 234}U in relation to {sup 238}U in the weathered rocks. The ({sup 226}Ra/{sup 238}U) and ({sup 226}Ra/{sup 234}U) activity ratios of all investigated rocks are similar, showing a significant {sup 226}Ra depletion, which is probably caused by its preferential leaching. These results indicate that even samples macroscopically classified as fresh rocks, their systems have been opened for some geochemical changes. The high ({sup 234}U/{sup 238}U) activity ratios of groundwaters which are found in the fractures of these granitoids suggest their prolonged residence times in the aquifer and/or their percolation by other rocks presenting different geochemical properties. (author)

Zircon U-Pb chronology, geochemistry and Sr-Nd-Pb isotopic compositions of the Volcanic Rocks in the Elashan area, NW China: petrogenesis and tectonic implications

Science.gov (United States)

Zhou, H.; Wei, J.; Shi, W.; Li, P.; Chen, M.; Zhao, X.

2017-12-01

Elashan area is located in the intersection of the East Kunlun Orogenic Belt (EKOB) and the West Qinling Orogenic (WQOB). We present petrology, zircon U-Pb ages, whole-rock geochemistry and Sr-Nd-Pb isotopic compositions from the andesite and felsic volcanic rocks (rhyolite and rhyolitic tuffs) in Elashan group volcanic rock. The LA-ICP-MS zircon U-Pb age data indicate that the volcanic rocks are emplaced at 250 247 Ma. The volcanic rocks have high -K and aluminum - peraluminous characteristics, A/CNK = 1.07 1.82, δ ranges from 1.56 2.95, the main body is calc-alkaline rock. They are enriched in large ion lithophile elements (LILEs) and light rare earth elements (LREEs) and depleted in some high field strength elements (HFSEs, e.g., Nb, Ta, P and Ti), while having a flat heavy REE (HREEs) pattern. The ∑REE values of 178.68 to 298.11 ppm, average 230.50 ppm. The LREE/HREE values of 4.39 to 11.78 ppm, average 6.77 ppm. REE fractionation is obvious, REE distribution curve was right smooth, and have slightly negative Eu anomalies (Eu/Eu*=0.44-0.80, average 0.60), which as similar to the island arc volcanic rocks. The volcanic rocks have initial 87Sr/86Sr ratios of 0.71028-0.71232, ɛNd(t) values of -6.7 to -7.6, with T2DM-Nd ranging from 1561 to 1640 Ma. Pb isotopic composition (206 Pb / 204 Pb)t = 18.055 18.330, (207 Pb / 204 Pb)t = 15.586 15.618, (208 Pb / 204 Pb)t = 37.677 38.332. Geochemical and Sr-Nd-Pb isotopes indicates that Elashan group volcanic magma derived mainly from the lower crust. Elashan group volcanic rocks is the productive East Kunlun block and West Qinling block collision, which makes the thicken crust caused partial melting in the study area. The source rocks is probably from metamorphic sandstone of Bayankala. But with Y-Nb and Rb-(Y+Nb), R1-R2 and Rb/10-Hf-Ta*3 diagrams showing that intermediate-acid rocks mainly formed in volcanic arc-collision environment, probably the collision event is short , therefore rocks retain the original island

Atomic-Monolayer MoS2 Band-to-Band Tunneling Field-Effect Transistor

KAUST Repository

Lan, Yann Wen

2016-09-05

The experimental observation of band-to-band tunneling in novel tunneling field-effect transistors utilizing a monolayer of MoS2 as the conducting channel is demonstrated. Our results indicate that the strong gate-coupling efficiency enabled by two-dimensional materials, such as monolayer MoS2, results in the direct manifestation of a band-to-band tunneling current and an ambipolar transport.

Determination of radioactivity in Chinese phosphate rock and fertilizer

International Nuclear Information System (INIS)

Chen Jingjian; Zhu Yongyi; Yang Juncheng

1993-01-01

The presented paper reported the radioactivity of U-238, Ra-226, Th-232 and K-40 in Chinese phosphate rocks by gamma spectrographic analysis during 1985-1990. The results showed that the decay chain of U-238-Ra-226 was the main source of radionuclides in phosphate rocks. The radionuclides in phosphate fertilizer differed from the forms of phosphate fertilizer. U-238 was the most important radionuclide in phosphoric compound fertilizer. The transfer rate of radionuclides was also estimated. (2 figs., 1 tab.)

Investigate the capability of INAA absolute method to determine the concentrations of 238U and 232Th in rock samples

International Nuclear Information System (INIS)

Alnour, I.A.

2014-01-01

This work aimed to study the capability of INAA absolute method in determining the elemental concentration of 238 U and 232 Th in the rock samples. The INAA absolute method was implemented in PUSPATI TRIGA Mark II research reactor, Malaysian Nuclear Agency (NM). The accuracy of INAA absolute method was performed by analyzing the IAEA certified reference material (CRM) Soil-7. The analytical results showed the deviations between experimental and certified values were mostly less than 10 % with Z-score in most cases less than 1. In general, the results of analysed CRM Soil-7 show a good agreement between certified and experimental results which mean that the INAA absolute method can be used accurately for elemental analysis of uranium and thorium in various types of samples. The concentration of 238 U and 232 Th ranged from 1.77 to 24.25 and 0.88 to 95.50 ppm respectively. The highest value of 238 U and 232 Th was recorded for granite rock sample G17 of 238 U and sample G9 of 232 Th, whereas the lower value was 1.77 ppm of 238 U recorded in sandstone rock and 0.88 ppm of 232 Th for gabbro. Moreover, a comparison of the 238 U and 232 Th results obtained by the INAA absolute method shows an acceptable level of consistency with those obtained by the INAA relative method. (author)

Gas Transport through Fractured Rock near the U20az Borehole, Pahute Mesa, Nevada.

Science.gov (United States)

Rockhold, M.; Lowrey, J. D.; Kirkham, R.; Olsen, K.; Waichler, S.; White, M. D.; Wurstner White, S.

2017-12-01

Field experiments were performed in 2012-13 and 2016-17 at the U-20az testbed at the Nevada National Security Site to develop and evaluate capabilities for monitoring and modeling noble gas transport associated with underground nuclear explosions (UNE). Experiments were performed by injecting both chemical (CF2BR2, SF6) and radioactive (37Ar, 127Xe) gas species into the deep subsurface at this legacy UNE site and monitoring the breakthrough of the gases at different locations on or near the ground surface. Gas pressures were also monitored in both the chimney and at ground surface. Field experiments were modeled using the parallel, non-isothermal, two-phase flow and transport simulator, STOMP-GT. A site conceptual-numerical model was developed from a geologic framework model, and using a dual-porosity/permeability model for the constitutive relative permeability-saturation-capillary pressure relations of the fractured rock units. Comparisons of observed and simulated gas species concentrations show that diffusion is a highly effective transport mechanism under ambient conditions in the water-unsaturated fractured rock. Over-pressurization of the cavity during one of the field campaigns, and barometric pressure fluctuations are shown to result in enhanced gas transport by advection through fractures.

Paleoproterozoic mojaveprovince in northwestern Mexico? Isotopic and U-Pb zircon geochronologic studies of precambrian and Cambrian crystalline and sedimentary rocks, Caborca, Sonora

Science.gov (United States)

Lang, Farmer G.; Bowring, S.A.; Matzel, J.; Maldonado, G.E.; Fedo, C.; Wooden, J.

2005-01-01

Whole-rock Nd isotopic data and U-Pb zircon geochronology from Precambrian crystalline rocks in the Caborca area, northern Sonora, reveal that these rocks are most likely a segment of the Paleoproterozoic Mojave province. Supporting this conclusion are the observations that paragneiss from the ??? 1.75 Ga Bamori Complex has a 2.4 Ga Nd model age and contains detrital zircons ranging in age from Paleo- proterozoic (1.75 Ga) to Archean (3.2 Ga). Paragneisses with similar age and isotopic characteristics occur in the Mojave province in southern California. In addition, "A-type" granite exposed at the southern end of Cerro Rajon has ca 2.0 Ga Nd model age and a U-Pb zircon age of 1.71 Ga, which are similar to those of Paleoproterozoic granites in the Mojave province. Unlike the U.S. Mojave province, the Caborcan crust contains ca. 1.1 Ga granite (Aibo Granite), which our new Nd isotopic data suggest is largely the product of anatexis of the local Precambrian basement. Detrital zircons from Neoproterozoic to early Cambrian miogeoclinal arenites at Caborca show dominant populations ca. 1.7 Ga, ca. 1.4 Ga, and ca. 1.1 Ga, with subordinate Early Cambrian and Archean zircons. These zircons were likely derived predominately from North American crust to the east and northeast, and not from the underlying Caborcan basement. The general age and isotopic similarities between Mojave province basement and overlying miogeoclinal sedimentary rocks in Sonora and southern California is necessary, but not sufficient, proof of the hypothesis that Sonoran crust is allochthonous and was transported to its current position during the Mesozoic along the proposed Mojave-Sonora megashear. One viable alternative model is that the Caborcan Precambrian crust is an isolated, autochthonous segment of Mojave province crust that shares a similar, but not identical, Proterozoic geological history with Mojave province crust found in the southwest United States ?? 2005 Geological Society of America.

Determination of uranium concentrations and "2"3"4U/"2"3"8U activity ratio in some granitic rock samples by alpha spectrometry: application of a radiochemical procedure

International Nuclear Information System (INIS)

Khattab, Mahmoud R.

2016-01-01

The present study is an application of a radiochemical procedure using alpha spectrometry technique for determination of uranium isotopes "2"3"8U, "2"3"4U and "2"3"5U on 13 granitic samples. These samples were collected from Gabal Gattar area, Northeastern Desert, Egypt. The collected samples were digested using microwave technique with aqua regia and spiked with "2"3"2U for chemical yield and activity calculation. Separation of uranium isotopes from the samples was done by Dowex 1 x 4 (50-100 mesh) resin followed by source preparation using microprecipitation technique. The concentrations of "2"3"8U were ranged between 28.9±0.9 and 134.8±1.8 Bq/g, and the "2"3"4U concentrations were between 24±0.6 and 147.7±2.2 Bq/g. For the "2"3"5U, the activity concentrations were between 1.3±0.2 and 6.7±1.2 Bq/g. The activity ratio of "2"3"4U/"2"3"8U was calculated and varied from 0.80 to 1.30. (author)

Multiverso: Rock'n'Astronomy

Science.gov (United States)

Caballero, J. A.

2012-05-01

In the last few years, there have been several projects involving astronomy and classical music. But have a rock band ever appeared at a science conference or an astronomer at a rock concert? We present a project, Multiverso, in which we mix rock and astronomy, together with poetry and video art (Caballero, 2010). The project started in late 2009 and has already reached tens of thousands people in Spain through the release of an album, several concert-talks, television, radio, newspapers and the internet.

Spin-polarized investigation of ferromagnetism on magnetic semiconductors Mn{sub x}Ca{sub 1−x}S in the rock-salt phase

Energy Technology Data Exchange (ETDEWEB)

Choutri, H.; Ghebouli, M.A. [LMSE Laboratory, University of Bachir Ibrahimi, 34265 Bordj-Bou-Arréridj (Algeria); Ghebouli, B. [Laboratory of Surface and Interface Studies of Solid Materials, Department of Physics, Faculty of Science, Setif University 1, Setif 19000 (Algeria); Bouarissa, N., E-mail: n_bouarissa@yahoo.fr [Department of Physics, Faculty of Science, University of M' sila, 28000 M' sila (Algeria); Uçgun, E.; Ocak, H.Y. [Department of Physics, Faculty of Arts and Sciences, Dumlupinar University, Kutahya (Turkey)

2014-12-15

The structural, elastic, electronic and magnetic properties of the diluted magnetic semiconductors Mn{sub x}Ca{sub 1−x}S in the rock-salt phase have been investigated using first-principles calculations with both LDA and LDA + U functional. Features such as lattice constant, bulk modulus, elastic constants, spin-polarized band structure, total and local densities of states have been computed. We predict the values of the exchange constants and the band edge spin splitting of the valence and conduction bands. The hybridization between S-3p and Mn-3d produces small local magnetic moment on the nonmagnetic Ca and S sites. The ferromagnetism is induced due to the exchange splitting of S-3p and Mn-3d hybridized bands. The total magnetic moment per Mn of Mn{sub x}Ca{sub 1−x}S is 4.4μ{sub B} and 4.5μ{sub B} for LDA and LDA + U functional and is independent of the Mn concentration. The unfilled Mn-3d levels reduce the local magnetic moment of Mn from its free space charge value of 5μ{sub B}–4.4μ{sub B} and4.5μ{sub B} for LDA and LDA + U functional due to 3p–3d hybridization. - Highlights: • Fundamental properties of magnetic semiconductors Mn{sub x}Ca{sub 1−x}S. • Rock-salt phase of Mn{sub x}Ca{sub 1−x}S. • Magnetic properties of the diluted magnetic semiconductors Mn{sub x}Ca{sub 1−x}S. • The use of LDA + U functionals.

Energy Impacts of Wide Band Gap Semiconductors in U.S. Light-Duty Electric Vehicle Fleet.

Science.gov (United States)

Warren, Joshua A; Riddle, Matthew E; Graziano, Diane J; Das, Sujit; Upadhyayula, Venkata K K; Masanet, Eric; Cresko, Joe

2015-09-01

Silicon carbide and gallium nitride, two leading wide band gap semiconductors with significant potential in electric vehicle power electronics, are examined from a life cycle energy perspective and compared with incumbent silicon in U.S. light-duty electric vehicle fleet. Cradle-to-gate, silicon carbide is estimated to require more than twice the energy as silicon. However, the magnitude of vehicle use phase fuel savings potential is comparatively several orders of magnitude higher than the marginal increase in cradle-to-gate energy. Gallium nitride cradle-to-gate energy requirements are estimated to be similar to silicon, with use phase savings potential similar to or exceeding that of silicon carbide. Potential energy reductions in the United States vehicle fleet are examined through several scenarios that consider the market adoption potential of electric vehicles themselves, as well as the market adoption potential of wide band gap semiconductors in electric vehicles. For the 2015-2050 time frame, cumulative energy savings associated with the deployment of wide band gap semiconductors are estimated to range from 2-20 billion GJ depending on market adoption dynamics.

Infrared Spectra of the 10-μm Bands of 1,2-Difluoroethane and 1,1,2-Trifluoroethane: Vibrationally Mediated Torsional Tunneling in 1,1,2-Trifluoroethane

Science.gov (United States)

Stone, Stephen C.; Miller, C. Cameron; Philips, Laura A.; Andrews, A. M.; Fraser, G. T.; Pate, B. H.; Xu, Li-Hong

1995-12-01

The 3-MHz-resolution infrared spectra of the 10-μm bands of thegaucheconformer of 1,2-difluoroethane (HFC152) and theC1-symmetry conformer of 1,1,2-trifluoroethane (HFC143) have been measured using a molecular-beam electric-resonance optothermal spectrometer with a tunable microwave-sideband CO2laser source. For 1,2-difluoroethane, two bands have been studied, the ν17B-symmetry C-F stretch at 1077.3 cm-1and the ν13B-symmetry CH2rock at 896.6 cm-1. Both bands are well fit to a asymmetric-rotor Hamiltonian to better than 0.5 MHz. The ν13band is effectively unperturbed, while the ν17band is weakly perturbed, as shown by the large change in centrifugal distortion constants from the ground state values. Two bands have also been studied for 1,1,2-trifluoroethane, the ν11symmetric CF2stretch at 1077.2 cm-1and the ν13C-C stretch at 905.1 cm-1. One of the two bands, ν11, is unperturbed and fit to near the experimental precision. The ν13vibration, on the other hand, is weakly perturbed by an interaction with a nearby state. This perturbation leads to a doubling or splitting of the lines, due to a perturbation-induced lifting of the degeneracy of the symmetric and antisymmetric tunneling states associated with tunneling between the two equivalentC1forms. For theJ,Kastates studied, the splittings are as large as 37 MHz. Combining this observation with published low-resolution far-infrared measurements of torsional sequence-band and hot-band frequencies and calculations from an empirical torsional potential allows us to identify the perturbing state as ν17+ 6ν18. Here, ν17is the CF2twist and ν18is the torsion. The matrix element responsible for this interaction exchanges eight vibrational quanta!

U-Pb zircon geochronology and evolution of some Adirondack meta-igneous rocks

Science.gov (United States)

Mclelland, J. M.

1988-01-01

An update was presented of the recent U-Pb isotope geochronology and models for evolution of some of the meta-igneous rocks of the Adirondacks, New York. Uranium-lead zircon data from charnockites and mangerites and on baddeleyite from anorthosite suggest that the emplacement of these rocks into a stable crust took place in the range 1160 to 1130 Ma. Granulite facies metamorphism was approximately 1050 Ma as indicated by metamorphic zircon and sphene ages of the anorthosite and by development of magmatitic alaskitic gneiss. The concentric isotherms that are observed in this area are due to later doming. However, an older contact metamorphic aureole associated with anorthosite intrusion is observed where wollastonite develops in metacarbonates. Zenoliths found in the anorthosite indicate a metamorphic event prior to anorthosite emplacement. The most probable mechanism for anorthosite genesis is thought to be ponding of gabbroic magmas at the Moho. The emplacement of the anorogenic anorthosite-mangerite-charnockite suite was apparently bracketed by compressional orogenies.

10 CFR 960.5-2-9 - Rock characteristics.

Science.gov (United States)

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Rock characteristics. 960.5-2-9 Section 960.5-2-9 Energy... Rock characteristics. (a) Qualifying condition. The site shall be located such that (1) the thickness and lateral extent and the characteristics and composition of the host rock will be suitable for...

Characterization of calculation of in-situ retardation factors of contaminant transport using naturally-radionuclides and rock/water interaction occurring U-Series disequilibria timescales. 1997 annual progress report

International Nuclear Information System (INIS)

Goldstein, S.; Ku, T.L.; Luo, S.; Murrel, M.; Roback, R.

1997-01-01

'The research is directed toward a quantitative assessment of contaminant transport rates in fracture-rock systems using uranium-series radionuclides. Naturally occurring uranium-and thorium-series radioactive disequilibria will provide information on the rates of adsorption-desorption and transport of radioactive contaminants as well as on fluid transport and rock dissolution in a natural setting. This study will also provide an improved characterization of preferential flow and contaminant transport at the Idaho Environmental and Engineering Lab. (INEEL) site. To a lesser extent, the study will include rocks in the unsaturated zone. The authors will produce a realistic model of radionuclide migration under unsaturated and saturated field conditions at the INEEL site, taking into account the retardation processes involved in the rock/water interaction. The major tasks are to (1) determine the natural distribution of U, Th, Pa and Ra isotopes in rock minerals. sorbed phases on the rocks, and in fluids from both saturated and unsaturated zones at the site, and (2) study rock/water interaction processes using U/Th series disequilibrium and a statistical analysis-based model for the Geologic heterogeneity plays an important role in transporting contaminants in fractured rocks. Preferential flow paths in the fractured rocks act as a major pathway for transport of radioactive contaminants in groundwaters. The weathering/dissolution of rock by groundwater also influences contaminant mobility. Thus, it is important to understand the hydrogeologic features of the site and their impact on the migration of radioactive contaminants. In this regard, quantification of the rock weathering/dissolution rate and fluid residence time from the observed decay-series disequilibria will be valuable. By mapping the spatial distribution of the residence time of groundwater in fractured rocks, the subsurface preferential flow paths (with high rock permeability and short fluid residence

Structural instability and ground state of the U_2Mo compound

International Nuclear Information System (INIS)

Losada, E.L.; Garcés, J.E.

2015-01-01

This work reports on the structural instability at T = 0 °K of the U_2Mo compound in the C11_b structure under the distortion related to the C_6_6 elastic constant. The electronic properties of U_2Mo such as density of states (DOS), bands and Fermi surface (FS) are studied to understand the source of the instability. The C11_b structure can be interpreted as formed by parallel linear chains along the z-directions each one composed of successive U–Mo–U blocks. Hybridization due to electronic interactions inside the U–Mo–U blocks is slightly modified under the D_6 distortion. The change in distance between chains modifies the U–U interaction and produces a split of f-states. The distorted structure is stabilized by a decrease in energy of the hybridized states, mainly between d-Mo and f-U states, together with the f-band split. Consequently, an induced Peierls distortion is produced in U_2Mo due to the D_6 distortion. It is important to note that the results of this work indicate that the structure of the ground state of the U_2Mo compound is not the assumed C11_b structure. It is suggested for the ground state a structure with hexagonal symmetry (P6 #168), ∼0.1 mRy below the energy of the recently proposed Pmmn structure. - Highlights: • Structural instability of the C11b compound due to the D6 deformation. • Induced Peierls distortion due to the D6 deformation. • Distorted structure is stabilized by hybridization and split of f-Uranium state. • P6 (#168) suggested ground state for the U_2Mo compound.

Resonant enhancement of band-to-band tunneling in in-plane MoS2/WS2 heterojunctions

Science.gov (United States)

Kuroda, Tatsuya; Mori, Nobuya

2018-04-01

The band-to-band (BTB) tunneling current J through in-plane MoS2/WS2 heterojunctions is calculated by the nonequilibrium Green function method combined with tight-binding approximation. Types A and B of band configurations are considered. For type-A (type-B) heterojunctions, a potential notch exists (or is absent) at the heterointerface. Both type-A and type-B MoS2/WS2 heterojunctions can support a higher BTB current than MoS2 and WS2 homojunctions. For type-A heterojunctions, the resonant enhancement of J occurs resulting in a significantly higher BTB tunneling current.

ONKALO rock mechanics model (RMM). Version 2.3

Energy Technology Data Exchange (ETDEWEB)

Haekkinen, T.; Merjama, S.; Moenkkoenen, H. [WSP Finland, Helsinki (Finland)

2014-07-15

The Rock Mechanics Model of the ONKALO rock volume includes the most important rock mechanics features and parameters at the Olkiluoto site. The main objective of the model is to be a tool to predict rock properties, rock quality and hence provide an estimate for the rock stability of the potential repository at Olkiluoto. The model includes a database of rock mechanics raw data and a block model in which the rock mechanics parameters are estimated through block volumes based on spatial rock mechanics raw data. In this version 2.3, special emphasis was placed on refining the estimation of the block model. The model was divided into rock mechanics domains which were used as constraints during the block model estimation. During the modelling process, a display profile and toolbar were developed for the GEOVIA Surpac software to improve visualisation and access to the rock mechanics data for the Olkiluoto area. (orig.)

Determination of the isotopic abundance of 235U in rocks in search for an Oklo phenomenon in Brazil by activation analysis

International Nuclear Information System (INIS)

Vasconcellos, M.B.A.; Armelin, M.J.A.; Lima, F.W. de; Fulfaro, R.

1981-09-01

Isotopic analyses of uranium are generally carried out by mass spectrometry, with a precision better than 1%. In nuclear laboratories it is often necessary to perform rapid determinations of 235 U isotopic abundances. Thermal neutron activation analysis by delayed neutron counting or by high resolution gamma-ray spectrometry can be applied for this purpose, although with less precision than by mass spectrometry. In this work, delayed neutron counting and gamma-ray spectrometry are used for the determination of the isotopic abundance of 235 U in rocks from the Northeastern region of Brazil. In the case of the application of delayed neutron counting, the rocks are analyzed non-destructively. When high resolution gamma-ray spectrometry is applied, a pre-irradiation chemical separation had to be performed, by extraction of uranium with tributylphosphate. By both methods employed the results for the isotopic abundance of 235 U can be considered as equal to the natural value of 0.702%, for the rocks under study. The precision attained by gamma-ray spectrometry is better than that by delayed neutron couting. (Author) [pt

Geochemistry of the U,Th and others lithophile elements in highgrade methamorphic rocks from 'Macico de Guaxupe', south Minas Gerais

International Nuclear Information System (INIS)

Fernandes, J.F.

1982-01-01

A geochemical investigation on the Silvianopolis complex, Minas Gerais, Brazil, has been carried out with the determination of lithophile elements like U, Th, Rb, K, etc. in rocks of different metamorphic grade. It is verified that the geochemical mobilities of the elements is dependant on the rock type. The elemental abundances and ratios are compared using a statistical test. (ARHC) [pt

Wide-band fanned-out supercontinuum source covering O-, E-, S-, C-, L- and U-bands

Science.gov (United States)

Ahmad, H.; Latif, A. A.; Awang, N. A.; Zulkifli, M. Z.; Thambiratnam, K.; Ghani, Z. A.; Harun, S. W.

2012-10-01

A wide-band supercontinuum source generated by mode-locked pulses injected into a Highly Non-Linear Fiber (HNLF) is proposed and demonstrated. A 49 cm long Bismuth-Erbium Doped Fiber (Bi-EDF) pumped by two 1480 nm laser diodes acts as the active gain medium for a ring fiber laser, from which mode-locked pulses are obtained using the Non-Polarization Rotation (NPR) technique. The mode-locked pulses are then injected into a 100 m long HLNF with a dispersion of 0.15 ps/nm km at 1550 nm to generate a supercontinuum spectrum spanning from 1340 nm to more than 1680 nm with a pulse width of 0.08 ps and an average power of -17 dBm. The supercontinuum spectrum is sliced using a 24 channel Arrayed Waveguide Grating (AWG) with a channel spacing of 100 GHz to obtain a fanned-out laser output covering the O-, E-, S-, C-, L- and U-bands. The lasing wavelengths obtained have an average pulse width of 9 ps with only minor fluctuations and a mode-locked repetition rate of 40 MHz, and is sufficiently stable to be used in a variety of sensing and communication applications, most notably as cost-effective sources for Fiber-to-the-Home (FTTH) networks.

Mapping hydrothermally altered rocks at Cuprite, Nevada, using the advanced spaceborne thermal emission and reflection radiometer (Aster), a new satellite-imaging system

Science.gov (United States)

Rowan, L.C.; Hook, S.J.; Abrams, M.J.; Mars, J.C.

2003-01-01

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a 14-band multispectral instrument on board the Earth Observing System (EOS), TERRA. The three bands between 0.52 and 0.86 ??m and the six bands from 1.60 and 2.43 ??m, which have 15- and 30-m spatial resolution, respectively, were selected primarily for making remote mineralogical determinations. The Cuprite, Nevada, mining district comprises two hydrothermal alteration centers where Tertiary volcanic rocks have been hydrothermally altered mainly to bleached silicified rocks and opalized rocks, with a marginal zone of limonitic argilized rocks. Country rocks are mainly Cambrian phyllitic siltstone and limestone. Evaluation of an ASTER image of the Cuprite district shows that spectral reflectance differences in the nine bands in the 0.52 to 2.43 ??m region provide a basis for identifying and mapping mineralogical components which characterize the main hydrothermal alteration zones: opal is the spectrally dominant mineral in the silicified zone; whereas, alunite and kaolinite are dominant in the opalized zone. In addition, the distribution of unaltered country rocks was mapped because of the presence of spectrally dominant muscovite in the siltstone and calcite in limestone, and the tuffaceous rocks and playa deposits were distinguishable due to their relatively flat spectra and weak absorption features at 2.33 and 2.20 ??m, respectively. An Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) image of the study area was processed using a similar methodology used with the ASTER data. Comparison of the ASTER and AVIRIS results shows that the results are generally similar, but the higher spectral resolution of AVIRIS (224 bands) permits identification of more individual minerals, including certain polymorphs. However, ASTER has recorded images of more than 90 percent of the Earth's land surface with less than 20 percent cloud cover, and these data are available at nominal or no cost

Structural instability and ground state of the U{sub 2}Mo compound

Energy Technology Data Exchange (ETDEWEB)

Losada, E.L., E-mail: losada@cab.cnea.gov.ar [SIM" 3, Centro Atómico Bariloche, Comisión Nacional de Energía Atómica (Argentina); Garcés, J.E. [Gerencia de Investigación y Aplicaciones Nucleares, Comisión Nacional de Energía Atómica (Argentina)

2015-11-15

This work reports on the structural instability at T = 0 °K of the U{sub 2}Mo compound in the C11{sub b} structure under the distortion related to the C{sub 66} elastic constant. The electronic properties of U{sub 2}Mo such as density of states (DOS), bands and Fermi surface (FS) are studied to understand the source of the instability. The C11{sub b} structure can be interpreted as formed by parallel linear chains along the z-directions each one composed of successive U–Mo–U blocks. Hybridization due to electronic interactions inside the U–Mo–U blocks is slightly modified under the D{sub 6} distortion. The change in distance between chains modifies the U–U interaction and produces a split of f-states. The distorted structure is stabilized by a decrease in energy of the hybridized states, mainly between d-Mo and f-U states, together with the f-band split. Consequently, an induced Peierls distortion is produced in U{sub 2}Mo due to the D{sub 6} distortion. It is important to note that the results of this work indicate that the structure of the ground state of the U{sub 2}Mo compound is not the assumed C11{sub b} structure. It is suggested for the ground state a structure with hexagonal symmetry (P6 #168), ∼0.1 mRy below the energy of the recently proposed Pmmn structure. - Highlights: • Structural instability of the C11b compound due to the D6 deformation. • Induced Peierls distortion due to the D6 deformation. • Distorted structure is stabilized by hybridization and split of f-Uranium state. • P6 (#168) suggested ground state for the U{sub 2}Mo compound.

Identification of Uranium Minerals in Natural U-Bearing Rocks Using Infrared Reflectance Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Beiswenger, Toya N. [Pacific Northwest National Laboratory, Richland, WA, USA; Gallagher, Neal B. [Eigenvector Research, Inc., Manson, WA, USA; Myers, Tanya L. [Pacific Northwest National Laboratory, Richland, WA, USA; Szecsody, James E. [Pacific Northwest National Laboratory, Richland, WA, USA; Tonkyn, Russell G. [Pacific Northwest National Laboratory, Richland, WA, USA; Su, Yin-Fong [Pacific Northwest National Laboratory, Richland, WA, USA; Sweet, Lucas E. [Pacific Northwest National Laboratory, Richland, WA, USA; Lewallen, Tricia A. [Pacific Northwest National Laboratory, Richland, WA, USA; Johnson, Timothy J. [Pacific Northwest National Laboratory, Richland, WA, USA

2017-10-24

The identification of minerals, including uranium-bearing minerals, is traditionally a labor-intensive-process using x-ray diffraction (XRD), fluorescence, or other solid-phase and wet chemical techniques. While handheld XRD and fluorescence instruments can aid in field identification, handheld infrared reflectance spectrometers can also be used in industrial or field environments, with rapid, non-destructive identification possible via spectral analysis of the solid’s reflectance spectrum. We have recently developed standard laboratory measurement methods for the infrared (IR) reflectance of solids and have investigated using these techniques for the identification of uranium-bearing minerals, using XRD methods for ground-truth. Due to the rich colors of such species, including distinctive spectroscopic signatures in the infrared, identification is facile and specific, both for samples that are pure or are partially composed of uranium (e.g. boltwoodite, schoepite, tyuyamunite, carnotite, etc.) or non-uranium minerals. The method can be used to detect not only pure and partial minerals, but is quite sensitive to chemical change such as hydration (e.g. schoepite). We have further applied statistical methods, in particular classical least squares (CLS) and multivariate curve resolution (MCR) for discrimination of such uranium minerals and two uranium pure chemicals (U3O8 and UO2) against common background materials (e.g. silica sand, asphalt, calcite, K-feldspar) with good success. Each mineral contains unique infrared spectral features; some of the IR features are similar or common to entire classes of minerals, typically arising from similar chemical moieties or functional groups in the minerals: phosphates, sulfates, carbonates, etc. These characteristic 2 infrared bands generate the unique (or class-specific) bands that distinguish the mineral from the interferents or backgrounds. We have observed several cases where the chemical moieties that provide the

U-Pb zircon geochronology and Sm-Nd-Pb isotopic constraint for precambrian plutonic rocks in the northeastern part of Ryeongnam massif, Korea

International Nuclear Information System (INIS)

Chang, Ho-Wan

2003-01-01

The Ryeongnam massif is composed of Precambrian gneisses, Paleozoic and Mesozoic sedimentary rocks and extensive Triassic-Jurassic plutonic rocks of felsic to mafic composition. In the northeast Ryeongnam massif, the oldest rocks belong to the Sobaegsan gneiss complex, which is composed of orthogneisses, paragneisses and mafic plutonic rocks. U-Pb zircon ages for the felsic and mafic intrusive bodies within the Sobaegsan gneiss complex are: the Icheon granite gneiss, 2357±43 and 2342±47 Ma; the Buncheon granite gneiss, 1963±5 Ma; the Pyeonghae granite gneiss, 1936±21 Ma; the Ogbang amphibolite, 1918±10 Ma; the Imwon leucogranite gneiss, 1826±20 Ma. The Hyeondong biotite schist, which is intruded by the Buncheon granite gneiss and the Ogbang amphibolite, yielded an age of 2271±44 Ma. The Nd-Sm-Pb isotopic data indicate that the felsic plutonic rocks are derived from an older Archean crust. The Nd T DM ages are Archean, and the εNd values are negative for the felsic rocks and positive for the amphibolite. Common Pb isotope compositions also indicate a crustal source for the felsic intrusives. The U-Pb ages of Precambrian rocks of the Ryeongnam massifs are similar to those in the Gyeonggi massif, and may have a similar crustal evolutionary history. The Precambrian rocks of South Korea could be related either to the North China block or to the South China block, as the isotope ages and patterns are not unique to either block. Similarly, a geologic correlation with Japan, although possible, is tenuous at present. (author)

Uranium and thorium in rocks and minerals of Zaangarsk alkaline massif

International Nuclear Information System (INIS)

Zhmodin, S.M.; Gofman, A.M.; Ksenzova, V.I.; Malmova, Z.V.; Nemirovskaya, N.A.

1981-01-01

U and Th distribution in rocks of the massif of alkaline-granitoid formation is studied using the methods of γ-spectrometry and neutron- fragment radiography. Predominant accumulation of U and Th in final products of magmatic differentiation - foyaites - is established. U and Th concentrations increased sharply during postmagmatic stage of alkaline massif formation - in permatites and metasomatically alterated rocks (Th/U and U/K ratios can serve as criteria for identification of such formations). The increase of U part, connected with accessory minerals in pegmatites and metasomatically alterated rocks, is pointed out. For U in postmagmatically alterated rocks high concentrations due to microcracks are characteristic [ru

Determination of U{sub 3}O{sub 8} in UO{sub 2} by infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Silva, Liliane Aparecida; Lameiras, Fernando Soares; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa; Barbosa, Joao Batista Santos, E-mail: lasfisica@gmail.com, E-mail: sl@cdtn.br, E-mail: amms@cdtn.br, E-mail: ferrazw@cdtn.br, E-mail: jbsb@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), Belo Horizonte, MG (Brazil)

2017-01-15

The oxygen-uranium (O-U) system has various oxides, such as UO{sub 2}, U{sub 4}O{sub 9}, U{sub 3}O{sub 8}, and UO{sub 3}. Uranium dioxide is the most important one because it is used as nuclear fuel in nuclear power plants. UO{sub 2} can have a wide stoichiometric variation due to excess or deficiency of oxygen in its crystal lattice, which can cause significant modifications of its proprieties. O/U relation determination by gravimetry cannot differentiate a stoichiometric deviation from contents of other uranium oxides in UO{sub 2}. The presence of other oxides in the manufacturing of UO{sub 2} powder or sintered pellets is a critical factor. Fourier Transform Infrared Spectroscopy (FTIR) was used to identify U{sub 3}O{sub 8} in samples of UO{sub 2} powder. UO{sub 2} can be identified by bands at 340 cm{sup -1} and 470 cm{sup -1}, and U{sub 3}O{sub 8} and UO{sub 3} by bands at 735 cm{sup -1}, 910 cm{sup -1}, respectively. The methodology for sample preparation for FTIR spectra acquisition is presented, as well as the calibration for quantitative measurement of U{sub 3}O{sub 8} in UO{sub 2}. The content of U{sub 3}O{sub 8} in partially calcined samples of UO{sub 2} powder was measured by FTIR with good agreement with X-rays diffractometry (XRD). (author)

Uranium deposits in granitic rocks

International Nuclear Information System (INIS)

Nishimori, R.K.; Ragland, P.C.; Rogers, J.J.W.; Greenberg, J.K.

1977-01-01

This report is a review of published data bearing on the geology and origin of uranium deposits in granitic, pegmatitic and migmatitic rocks with the aim of assisting in the development of predictive criteria for the search for similar deposits in the U.S. Efforts were concentrated on the so-called ''porphyry'' uranium deposits. Two types of uranium deposits are primarily considered: deposits in pegmatites and alaskites in gneiss terrains, and disseminations of uranium in high-level granites. In Chapter 1 of this report, the general data on the distribution of uranium in igneous and metamorphic rocks are reviewed. Chapter 2 contains some comments on the classification of uranium deposits associated with igneous rocks and a summary of the main features of the geology of uranium deposits in granites. General concepts of the behavior of uranium in granites during crustal evolution are reviewed in Chapter 3. Also included is a discussion of the relationship of uranium mineralization in granites to the general evolution of mobile belts, plus the influence of magmatic and post-magmatic processes on the distribution of uranium in igneous rocks and related ore deposits. Chapter 4 relates the results of experimental studies on the crystallization of granites to some of the geologic features of uranium deposits in pegmatites and alaskites in high-grade metamorphic terrains. Potential or favorable areas for igneous uranium deposits in the U.S.A. are delineated in Chapter 5. Data on the geology of specific uranium deposits in granitic rocks are contained in Appendix 1. A compilation of igneous rock formations containing greater than 10 ppM uranium is included in Appendix 2. Appendix 3 is a report on the results of a visit to the Roessing area. Appendix 4 is a report on a field excursion to eastern Canada

Contributions to the petrography, geochemistry and geochronology (U-Pb and Sm-Nd) of the Paleoproterozoic effusive rocks from Iricoume Group, Amazonian Craton, Brazil

Energy Technology Data Exchange (ETDEWEB)

Marques, Suelen Nonata de Souza; Nascimento, Rielva Solimairy Campelo do, E-mail: suelen-marques@hotmail.com, E-mail: rielva@ufam.edu.br [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Inst. de Geociencias; Souza, Valmir da Silva; Dantas, Elton Luiz, E-mail: vsouza@unb.br, E-mail: elton@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Geociencias; Valerio, Cristovao da Silva, E-mail: cristovao@igeo.ufrr.br [Universidade Federal de Roraima (UFRR), Boa Vista, RR (Brazil). Inst. de Geociencias

2014-07-01

The southernmost region of the Guyana shield, Amazonian craton, hosts large record of Paleoproterozoic effusive rocks of the Iricoume Group. They present remarkably well-preserved igneous textures and structures. The SiO{sub 2} contents reveal a bimodal association marked by a compositional gap between acid (SiO{sub 2} > 67 wt%) and intermediate (SiO{sub 2} < 57.7 wt%) rocks. The acid effusive rocks are rhyolites to rhyodacites with high SiO{sub 2}, alkali, Rb, Zr, Nb + Ta, La + Ce and 104 Ga/Al content and low Fe{sub 2}O{sub 3tot}, TiO{sub 2}, CaO, Sr and Co content. They exhibit subalkaline, metaluminous-to-peraluminous compositions, and geochemically compatible to A-type magmatism emplaced in post-collisional to within-plate tectonic settings. The intermediate rocks are andesitic/basalt to andesite relatively high contents of TiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3total}, MgO, CaO, Sr and Co; low SiO{sub 2}, K{sub 2}O, Rb, Zr, Nb + Ta, La + Ce. They have subalkaline and metaluminous geochemical composition and plot on within-plate basalt field. The acid rocks crystallized at 1882 ± 11 Ma in U-Pb analyses for LA-MC-ICPMS zircon data. The Sm-Nd isotopic data on all rocks reveal a Nd TDM model ages between 2.59 and 2.16 Ga and ε{sub Nd}(t) values between -5.78 and 0.03, indicate that the magmatic evolution was related to the reworking of older Paleoproterozoic at the Rhyacian-Siderian period, continental crust (Transamazonian crust-forming event) with some mixing with a limited amount mantle-derived magmas or with contamination by Archean crust. The petrographic, geochemical and geochronological data presented in this paper suggest a within-plate to post-collisional tectonic setting for the Iricoume volcanism, involving lower crust uplift and generation of basalt magma in an extensional regime. (author)

10 CFR 960.3-1-2 - Diversity of rock types.

Science.gov (United States)

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Diversity of rock types. 960.3-1-2 Section 960.3-1-2... NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-2 Diversity of rock types. Consideration... sites for characterization shall have different types of host rock. ...

ASTER spectral sensitivity of carbonate rocks - Study in Sultanate of Oman

Science.gov (United States)

Rajendran, Sankaran; Nasir, Sobhi

2014-02-01

Remote sensing satellite data plays a vital role and capable in detecting minerals and discriminating rock types for explorations of mineral resources and geological studies. Study of spectral absorption characters of remotely sensed data are under consideration by the exploration and mining companies, and demonstrating the spectral absorption characters of carbonates on the cost-effective multispectral image (rather than the hyperspectral, Lidar image) for easy understanding of all geologists and exploration communities of carbonates is very much important. The present work is an integrated study and an outcome of recently published works on the economic important carbonate rocks, includes limestone, marl, listwaenites and carbonatites occurred in parts of the Sultanate of Oman. It demonstrates the spectral sensitivity of such rocks for simple interpretation over satellite data and describes and distinguishes them based on the absorptions of carbonate minerals in the spectral bands of advanced spaceborne thermal emission and reflection radiometer (ASTER) for mapping and exploration studies. The study results that the ASTER spectral band 8 discriminates the carbonate rocks due to the presence of predominantly occurred carbonate minerals; the ASTER band 5 distinguishes the limestones and marls (more hydroxyl clay minerals) from listwaenite (hydrothermally altered rock) due to the presence of altered minerals and the ASTER band 4 detects carbonatites (ultramafic intrusive alkaline rocks) which contain relatively more silicates. The study on the intensity of the total absorptions against the reflections of these rocks shows that the limestones and marls have low intensity in absorptions (and high reflection values) due to the presence of carbonate minerals (calcite and dolomite) occurred in different proportions. The listwaenites and carbonatites have high intensity of absorptions (low reflection values) due to the occurrence of Mn-oxide in listwaenites and carbonates

Relationships between data from Rock-Eval pyrolysis and proximate, ultimate, petrographic, and physical analyses of 142 diverse U.S. coal samples

Science.gov (United States)

Bostick, N.H.; Daws, T.A.

1994-01-01

Basic research on coal and oil shale led to automated pyrolysis analysis of petroleum source rocks; most widely used is the Rock-Eval equipment. In order to interpret Rock-Eval analyses in relation to traditional coal data, we analyzed 142 commercial coals with diverse rank, age, maceral and sulfur contents, for most regions of the United States. We compared the Rock-Eval data with traditional industrial coal data, including volatile matter, calorific value, hydrogen and oxygen content, free swelling index, and vitrinite reflectance. We found: (1) there is a close relationship between Tmax and vitrinite reflectance in the ranges 420-590??C Tmax and 0.4-3%Romax of most coals. (2) A close relationship between Tmax and volatile matter (%VM) extends through the entire sample range, including low-rank samples with 35-70% VM, a range where %VM is not considered to be a useful rank parameter. (3) TOC of medium- and high-rank coals is seriously under-measured by Rock-Eval; TOC of low-rank coals (less than 0.8%Romax) is close to "dry basis" carbon from ultimate analysis. (4) The direct relationships between oxygen index (OI) and %O and between hydrogen index (HI) and %H are clear, though only broadly defined. However, there is virtually no band of concentrated data points on the HI versus OI pseudo-Van Krevelen diagram comparable to the "development line" on the H/C versus O/C diagram. (5) There are systematic relationships between Rock-Eval and industrial coal parameters such as calorific value and FSI, but much standardization would be needed before Rock-Eval could find a place in the coal industry. Tests with blends of coal and quartz sand and with various loads of coal alone showed that the amount of organic matter in the Rock-Eval load greatly influences results. Total load in the crucible, if largely inert, plays a small role, however. Increasing absolute or relative coal content causes under-evaluation of Rock-Eval TOC and over-rating of hydrogen. Blends of several

The USNO-UKIRT K-band Hemisphere Survey

Science.gov (United States)

Dahm, Scott; Bruursema, Justice; Munn, Jeffrey A.; Vrba, Fred J.; Dorland, Bryan; Dye, Simon; Kerr, Tom; Varricatt, Watson; Irwin, Mike; Lawrence, Andy; McLaren, Robert; Hodapp, Klaus; Hasinger, Guenther

2018-01-01

We present initial results from the United States Naval Observatory (USNO) and UKIRT K-band Hemisphere Survey (U2HS), currently underway using the Wide Field Camera (WFCAM) installed on UKIRT on Maunakea. U2HS is a collaborative effort undertaken by USNO, the Institute for Astronomy, University of Hawaii, the Cambridge Astronomy Survey Unit (CASU) and the Wide Field Astronomy Unit (WFAU) in Edinburgh. The principal objective of the U2HS is to provide continuous northern hemisphere K-band coverage over a declination range of δ=0o – +60o by combining over 12,700 deg2 of new imaging with the existing UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS), Galactic Plane Survey (GPS) and Galactic Cluster Survey (GCS). U2HS will achieve a 5-σ point source sensitivity of K~18.4 mag (Vega), over three magnitudes deeper than the Two Micron All Sky Survey (2MASS). In this contribution we discuss survey design, execution, data acquisition and processing, photometric calibration and quality control. The data obtained by the U2HS will be made publicly available through the Wide Field Science Archive (WSA) maintained by the WFAU.

Strongly reduced band gap in NiMn2O4 due to cation exchange

International Nuclear Information System (INIS)

Huang, Jhih-Rong; Hsu, Han; Cheng, Ching

2014-01-01

NiMn 2 O 4 is extensively used as a basis material for temperature sensors due to its negative temperature coefficient of resistance (NTCR), which is commonly attributed to the hopping mechanism involving coexisting octahedral-site Mn 4+ and Mn 3+ . Using density-functional theory + Hubbard U calculations, we identify a ferrimagnetic inverse spinel phase as the collinear ground state of NiMn 2 O 4 . By a 12.5% cation exchange, a mixed phase with slightly higher energy can be constructed, accompanied by the formation of an impurity-like band in the original 1 eV band gap. This impurity-like band reduces the gap to 0.35 eV, suggesting a possible source of NTCR. - Highlights: • Density functional based calculations were used to study collinear phase of NiMn 2 O 4 . • The ground-state structure is a ferrimagnetic inverse spinel phase. • The tetrahedral and octahedral Mn cations have ferromagnetic interactions. • A 12.5% cation exchange introduces an impurity-like band in the original 1 eV gap. • The 0.35 eV gap suggests a source of negative temperature coefficient of resistance

U-series in Fe(III)-U(VI) rich fracture infill-materials from the oxidised cap of the U-ore deposit of Mina Fe (Salamanca, Spain): Implications for water/rock interaction processes affecting and analogue site (Matrix II project)

International Nuclear Information System (INIS)

Perez del Villar, L.; Grespo, M. T.; Quejido, A. J.

2002-01-01

In the frame of the ENRESA natural analogue programme. The U-ore deposit of Mina Fe being studied as a natural analogue of radioactive spent fuel behaviour. In this context the knowledge of the role played by fracture minerals as scavengers of certain analogue elements. Mainly U, and the establishment of the time scale of the rock-water interaction processes controlling the uptakes or losses of U in the system are two relevant objectives

Rock Mechanics Forsmark. Site descriptive modelling Forsmark stage 2.2

Energy Technology Data Exchange (ETDEWEB)

Glamheden, Rune; Fredriksson, Anders (Golder Associates AB (SE)); Roeshoff, Kennert; Karlsson, Johan (Berg Bygg Konsult AB (SE)); Hakami, Hossein (Itasca Geomekanik AB (SE)); Christiansson, Rolf (Swedish Nuclear Fuel and Waste Management Co., Stockholm (SE))

2007-12-15

The Swedish Nuclear Fuel and Waste Management Company (SKB) is undertaking site characterisation at two different locations, Forsmark and Laxemar/Simpevarp, with the objective of siting a geological repository for spent nuclear fuel. The characterisation of a site is an integrated work carried out by several disciplines including geology, rock mechanics, thermal properties, hydrogeology, hydrogeochemistry and surface systems. This report presents the rock mechanics model of the Forsmark site up to stage 2.2. The scope of work has included compilation and analysis of primary data of intact rock and fractures, estimation of the rock mass mechanical properties and estimation of the in situ state of stress at the Forsmark site. The laboratory results on intact rock and fractures in the target volume demonstrate a good quality rock mass that is strong, stiff and relatively homogeneous. The homogeneity is also supported by the lithological and the hydrogeological models. The properties of the rock mass have been initially estimated by two separate modelling approaches, one empirical and one theoretical. An overall final estimate of the rock mass properties were achieved by integrating the results from the two models via a process termed 'Harmonization'. Both the tensile tests, carried out perpendicular and parallel to the foliation, and the theoretical analyses of the rock mass properties in directions parallel and perpendicular to the major principal stress, result in parameter values almost independent of direction. This indicates that the rock mass in the target volume is isotropic. The rock mass quality in the target volume appears to be of high and uniform quality. Those portions with reduced rock mass quality that do exist are mainly related to sections with increased fracture frequency. Such sections are associated with deformation zones according to the geological description. The results of adjacent rock domains and fracture domains of the target

Lead isotopes in archaean plutonic rocks

International Nuclear Information System (INIS)

Oversby, V.M.

1978-01-01

Archaean intrusive rocks have initial Pb isotopic compositions which show a varied and complex history for the source regions of the rocks. Even the oldest rocks from Greenland indicate heterogenous U and Pb distribution prior to 3800 m.y. ago. Source regions with μ values less than 7 must have played a significant role in the early history of the earth. By late Archaean time U/Pb ratios of source regions had increased substantially. Data from Australia and North America show distinct regional differences, both within and between continents. (Auth.)

Transport of soluble species in backfill and rock

International Nuclear Information System (INIS)

Chambre, P.L.; Lee, W.W.L.; Light, W.B.; Pigford, T.H.

1992-03-01

In this report we study the release and transport of soluble species from spent nuclear fuel. By soluble species we mean a fraction of certain fission product species. Our previously developed methods for calculating release rates of solubility-limited species need to be revised for these soluble species. Here we provide methods of calculating release rates of soluble species directly into rock and into backfill and then into rock. Section 2 gives a brief discussion of the physics of fission products dissolution from U0 2 spent fuel. Section 3 presents the mathematics for calculating release rates of soluble species into backfill and then into rock. The calculation of release rates directly into rock is a special case. Section 4 presents numerical illustrations of the analytic results

Nightglow vibrational distributions in the A3Σu+ and A'3Δu states of O2 derived from astronomical sky spectra

Directory of Open Access Journals (Sweden)

T. G. Slanger

2004-09-01

Full Text Available Astronomical sky spectra from the Keck I telescope on Mauna Kea have been used to obtain vibrational distributions in the O2A3Σu+ and O2(A'3Δu states from rotationally-resolved Herzberg I and Chamberlain band emissions in the terrestrial nightglow. The A3Σu+ distribution is similar to that presented in earlier publications, with the exception that there is significant population in the previously undiscerned v=0 level. The vibrational distributions of the A'3Δu and A3Σu+ states are essentially the same when comparison is made in terms of the level energies. The intensity of Chamberlain band emission at the peak of the distribution is about one-fourth that of the Herzberg I emission, as previously shown, and may be related primarily to radiative efficiency. The peaks in both population distributions are about 0.25eV below the O(3P+O(3P dissociation limit. We compare these Herzberg state distributions with that of the O2(b1Σg+ state, concurring with others that the intense nightglow emission associated with b1Σg+(v=0 is a reflection of direct transfer from the Herzberg states. This process takes place following O2 collisions, with simultaneous production of very high a1Δg and b1Σg+ vibrational levels.

Oxygen and U-Th isotopes and the timescales of hydrothermal exchange and melting in granitoid wall rocks at Mount Mazama, Crater Lake, Oregon

Science.gov (United States)

Ankney, Meagan E.; Bacon, Charles R.; Valley, John W.; Beard, Brian L.; Johnson, Clark M.

2017-01-01

We report new whole rock U-Th and in-situ oxygen isotope compositions for partially melted (0–50 vol% melt), low-δ18O Pleistocene granitoid blocks ejected during the ∼7.7 ka caldera-forming eruption of Mt. Mazama (Crater Lake, Oregon). The blocks are interpreted to represent wall rocks of the climactic magma chamber that, prior to eruption, experienced variable amounts of exchange with meteoric hydrothermal fluids and subsequent partial melting. U-Th and oxygen isotope results allow us to examine the timescales of hydrothermal circulation and partial melting, and provide an “outside in” perspective on the buildup to the climactic eruption of Mt. Mazama. Oxygen isotope compositions measured in the cores and rims of individual quartz (n = 126) and plagioclase (n = 91) crystals, and for transects across ten quartz crystals, document zonation in quartz (Δ18OCore-Rim ≤ 0.1–5.5‰), but show homogeneity in plagioclase (Δ18OCore-Rim ≤ ±0.8‰). We propose that oxygen isotope zonation in quartz records hydrothermal exchange followed by high-temperature exchange in response to partial melting caused by injection of basaltic to andesitic recharge magma into the deeper portions of the chamber. Results of modeling of oxygen diffusion in quartz indicates that hydrothermal exchange in quartz occurred over a period of ∼1000–63,000 years. Models also suggest that the onset of melting of the granitoids occurred a minimum of ∼10–200 years prior to the Mazama climactic eruption, an inference which is broadly consistent with results for magnetite homogenization and for Zr diffusion in melt previously reported by others.Uranium-thorium isotope compositions of most granitoid blocks are in 238U excess, and are in agreement with a 238U enriched array previously measured for volcanic rocks at Mt. Mazama. Uranium excess in the granitoids is likely due to enrichment via hydrothermal circulation, given their low δ18O values. The sample with the

The participatory archive of the sites of Danish rock music culture

DEFF Research Database (Denmark)

Knudsen, Line Vestergaard

History” as an example of such a digital participatory archive. This digital online project is initiated by the Danish Rock Music Museum and intends to gather material that portray the sites’ and meeting places’ (such as venues, festivals, youth clubs etc.) of Danish rock music culture. Danish rock music......When setting out to tell the story of rock music culture, one approach is a focus at the “meeting places” where bands, fans and those behind the scenes have gathered. With this approach the cultural heritage of rock music becomes situated and site-specific, and it is nearby to think of ways...... to engage those who “inhabited” these specific sites of the previous 60 years of rock music culture. This paper will discuss how the issues of locality and rock music culture can be gathered and researched by a participatory (web 2.0) archive. The research is empirically focused at “The Map of Danish Rock...

Rock Hellsinki, Marketing Research

OpenAIRE

Todd, Roosa; Jalkanen, Katariina

2013-01-01

This paper is a qualitative research about rock and heavy metal music tourism in the capital city of Finland, Helsinki. As Helsinki can be considered the city of contrasts, the silent nature city mixed with urban activities, it is important to also use the potential of the loud rock and heavy metal music contrasting the silence. Finland is known abroad for bands such as HIM, Nightwish, Korpiklaani and Children of Bodom so it would make sense to utilize these in the tourism sector as well. The...

DFT+U study of defects in bulk rutile TiO₂

DEFF Research Database (Denmark)

Stausholm-Møller, Jess; Kristoffersen, Henrik Høgh; Hinnemann, Berit

2010-01-01

phase of bulk titanium dioxide. We find that by applying a sufficiently large value for the Hubbard-U parameter of the Ti 3d states, the excess electrons localize spatially at the Ti sites and appear as states in the band gap. At U = 2.5 eV, the position in energy of these gap states are in fair...... is that regardless of which structural defect is the origin of the gap states, at U = 2.5 eV, these states are found to have their mean energies within a few hundredths of an eV from 0.94 eV below the conduction band minimum.......We present a systematic study of electronic gap states in defected titania using our implementation of the Hubbard-U approximation in the grid-based projector-augmented wave density functional theory code, GPAW. The defects considered are Ti interstitials, O vacancies, and H dopants in the rutile...

Age determination of Precambrian rocks from Greenland: past and present

International Nuclear Information System (INIS)

Karlsbeek, F.

1997-01-01

For Precambrian rocks as well as for younger igneous intrusions, precise ages can only be obtained by isotopic analysis of minerals or rocks. Isotopic (radiometric) age determination of Greenland rocks began in the early 1960s and has continued since with gradually improving methods. In this contribution, the development of geochronological knowledge of the Precambrian of Greenland is described in historical perspective, and an outline of new results is given. The history of geochronology can be roughly divided into three periods: 1) a period of single-sample K-Ar and Rb-Sr mineral or whole-rock age determinations; 2) a time when most ages were determined with the help of Rb-Sr and Pb-Pb whole-rock isochrones and multi-grain zircon U-Pb isotope data; 3) the present, where 'single' zircon U-Pb data are the preferred method to obtain rock ages. These stages in the development of radiometric dating methods partly overlap in time, and each has yielded very significant contributions to the knowledge of Precambiran evolution in Greenland. (EG)

SHRIMP U-Pb dating of detrital zircons in metamorphic rocks from northern Kyushu, western Japan

International Nuclear Information System (INIS)

Tsutsumi, Yukiyasu; Yokoyama, Kazumi; Terada, Kentaro; Sano, Yuji

2003-01-01

Radiometric ages of detrital zircons in psammitic schists from the Nagasaki, Kurume, Konoha and Kiyama areas, northern Kyushu, were obtained from 238 U/ 206 Pb ratio and isotopic compositions of Pb using a Sensitive High Resolution Ion Microprobe (SHRIMP II). Zircons from the Nagasaki, Kurume and Konoha areas show bimodal age distribution with peaks at ca. 1900 Ma and 250 Ma. It is suggested from this study that the older zircons were derived from Proterozoic landmass and the Korean Peninsula. Zircons from the Kiyama metamorphic rock show a different pattern with ages concentrated at 380-590 Ma. Such zircons are rare in rock samples from the Nagasaki, Kurume and Konoha areas, indicating that Kiyama rocks and a different origin than those from the other three areas. The youngest zircons from the Kiyama, Nagasaki, Kurume and Konoha areas show ages of 382±23 Ma, 238±13 Ma, 249±13 Ma, and 175±4 Ma, respectively, These data mark the upper age limit of their deposition. Since a continuous igneous activity occurred during the period from 300 to 170 Ma in Far East Asia, and the metamorphic age has been close to the zircon age of each area, these youngest ages for the Nagasaki, Kurume and Konoha areas are considered nearly contemporary to the depositional ages. An evaluation of the nature of metamorphism and available ages suggest the possibility that the Nagasaki metamorphic rocks as well as the schist from the Kurume area belong to the Suo zone of the Sangun belt, whereas the metamorphic rocks in the Konoha area may belong to the Ryoke belt or Suo zone of the Sangun belt. (author)

ROCK1 and ROCK2 are Required for Non-Small Cell Lung Cancer Anchorage-Independent Growth and Invasion

OpenAIRE

Vigil, Dominico; Kim, Tai Young; Plachco, Ana; Garton, Andrew J.; Castaldo, Linda; Pachter, Jonathan A.; Dong, Hanqing; Chen, Xin; Tokar, Brianna; Campbell, Sharon L.; Der, Channing J.

2012-01-01

Evidence is emerging that the closely related ROCK1 and ROCK2 serine/threonine kinases support the invasive and metastatic growth of a spectrum of human cancer types. Therefore, inhibitors of ROCK are under preclinical development. However, a key step in their development involves the identification of genetic biomarkers that will predict ROCK inhibitor anti-tumor activity. One identified mechanism for ROCK activation in cancer involves the loss of function of the DLC1 tumor suppressor gene, ...

Uranium migration and retention during weathering of a granitic waste rock pile

International Nuclear Information System (INIS)

Boekhout, F.; Gérard, M.; Kanzari, A.; Michel, A.; Déjeant, A.; Galoisy, L.; Calas, G.; Descostes, M.

2015-01-01

Highlights: • We investigate the environmental impact of the granitic waste rock piles. • The majority of the waste rocks in the pile is barren- or overburden rock. • The main neo-formed U-bearing phases are (Ca) and (Cu) uranyl phosphates. • Under circum-neutral pH conditions they do not pose an environment threat. - Abstract: This study investigates the post-mining evolution of S-type granitic waste rocks around a former uranium mine, Vieilles Sagnes (Haute Vienne, NW Massif Central, France). This mine was operated between 1957 and 1965 in the La Crouzille former world-class uranium mining district and is representative of intra-granitic vein-type deposits. 50 years after mine closure and the construction and subsequent re-vegetation of the granitic waste rock pile, we evaluate the environmental evolution of the rock pile, including rock alteration, neo-formation of U-bearing phases during weathering, and U migration. Vertical trenches have been excavated through the rock pile down to an underlying paleo-soil, allowing the investigation of the vertical differentiation of the rock pile and its influence on water pathways, weathering processes and U migration and retention. Arenization dominantly drives liberation of U, by dissolution of uraninite inclusions in the most alterable granitic minerals (i.e. K-feldspar and biotite). Retention of U in the matrix at the base of the waste rock pile, and in the underlying paleo-soil most likely occurs by precipitation of (nano-) uranyl phosphates or a combination of co-precipitation and adsorption reactions of U onto Fe (oxy)hydroxides and/or clay minerals. Even though U-migration was observed, U is retained in stable secondary mineral phases, provided the current conditions will not be modified

Transient evoked otoacoustic emissions in rock musicians.

Science.gov (United States)

Høydal, Erik Harry; Lein Størmer, Carl Christian; Laukli, Einar; Stenklev, Niels Christian

2017-09-01

Our focus in this study was the assessment of transient evoked otoacoustic emissions (TEOAEs) in a large group of rock musicians. A further objective was to analyse tinnitus among rock musicians as related to TEOAEs. The study was a cross-sectional survey of rock musicians selected at random. A control group was included at random for comparison. We recruited 111 musicians and a control group of 40 non-musicians. Testing was conducted by using clinical examination, pure tone audiometry, TEOAEs and a questionnaire. TEOAE SNR in the half-octave frequency band centred on 4 kHz was significantly lower bilaterally in musicians than controls. This effect was strongly predicted by age and pure-tone hearing threshold levels in the 3-6 kHz range. Bilateral hearing thresholds were significantly higher at 6 kHz in musicians. Twenty percent of the musicians had permanent tinnitus. There was no association between the TEOAE parameters and permanent tinnitus. Our results suggest an incipient hearing loss at 6 kHz in rock musicians. Loss of TEOAE SNR in the 4 kHz half-octave frequency band was observed, but it was related to higher mean 3-6 kHz hearing thresholds and age. A large proportion of rock musicians have permanent tinnitus.

Release of U, Th, and REE from granitic rock: A mineralogical approach

International Nuclear Information System (INIS)

Markovaara-Koivisto, M.

2006-01-01

Finland plans to dispose of its spent nuclear fuel deep in the bedrock, and comprehensive assessment of the potential risks is required. One risk is glaciations induced by climate change, which might eventually cause malfunction of the engineered barrier system and breakdown of the copper-iron canisters containing the spent fuel. The fuel might then come into contact with groundwater. This groundwater might be acidic rain water, or oxygenated glacial melt water, which intrudes into the bedrock with hydrostatic pressure under the ice sheet. In this study, behaviour of uranium and rare earth elements was investigated in the Palmottu uranium deposit. Studies in the Palmottu deposit provide an indication of how uranium and other harmful elements could migrate from the repository to the surrounding bedrock in the event the canisters were breached. The spent fuel contains uranium and other actinides. The possible release of these elements and their behaviour after release in bedrock and groundwater were studied by means of chemical analogues occurring in nature, namely uranium (U), thorium (Th) and rare earth elements (REE). The study was focused on the mode of occurrence of these elements in granitic rocks. The chemistry of the mineral phases was explored by scanning electron microscopy and wavelength dispersive spectrometry, while the release of the elements was investigated with leaching experiments. In the first phase the samples were leached with artificial groundwater. In the second phase a HNO 3 solution of pH 5 was used, and in the final step a solution of pH 3. The U, Th and REE phases after each leaching were studied by fieldemission scanning electron microscopy and energy dispersive XRay microanalysis (EDAX), and the leachates were analysed by mass spectrometry (ICPMS and ICPAES). The aim of this study was to clarify how U, Th and REEs behave in the leaching processes associated with solutions simulating possible natural water conditions in the bedrock and to

Redox equilibrium of U4+/U3+ in molten NaCl-2CsCl by UV-Vis spectrophotometry and cyclic voltammetry

International Nuclear Information System (INIS)

Nagai, Takayuki; Uehara, Akihiro; Fujii, Toshiyuki; Shirai, Osamu; Yamana, Hajimu; Sato, Nobuaki

2005-01-01

In order to investigate the redox equilibrium of uranium ions in molten NaCl-2CsCl, UV-Vis absorption spectro-photometry measurements were performed for U 4+ and U 3+ in molten NaCl-2CsCl at 923 K under simultaneous electrolytic control of their ratio. Prominent absorption bands at 480 and 570 nm were assigned to U 3+ , and their molar absorptivities were determined to be 1,260±42 and 963±32 mol -1 ·l·cm -1 respectively. From the dependence of the rest potential of the melt on the spectrophotometrically determined ratio of [U 4+ ]/[U 3+ ], the standard redox potential of the couple U 4+ /U 3+ at 923 K was determined to be -1.481±0.004 V vs. Cl 2 /Cl - . Cyclic voltammetry measurements were carried out for the couple U 4+ /U 3+ , and the results agreed well with this standard redox potential value. By the results of cyclic voltammetry, a temperature dependence of the standard redox potential was found to be -2.094+6.639 x 10 -4 T (T=823-923K). (author)

Numerical simulation of rock cutting using 2D AUTODYN

International Nuclear Information System (INIS)

Woldemichael, D E; Rani, A M Abdul; Lemma, T A; Altaf, K

2015-01-01

In a drilling process for oil and gas exploration, understanding of the interaction between the cutting tool and the rock is important for optimization of the drilling process using polycrystalline diamond compact (PDC) cutters. In this study the finite element method in ANSYS AUTODYN-2D is used to simulate the dynamics of cutter rock interaction, rock failure, and fragmentation. A two-dimensional single PDC cutter and rock model were used to simulate the orthogonal cutting process and to investigate the effect of different parameters such as depth of cut, and back rake angle on two types of rocks (sandstone and limestone). In the simulation, the cutting tool was dragged against stationary rock at predetermined linear velocity and the depth of cut (1,2, and 3 mm) and the back rake angles(-10°, 0°, and +10°) were varied. The simulation result shows that the +10° back rake angle results in higher rate of penetration (ROP). Increasing depth of cut leads to higher ROP at the cost of higher cutting force. (paper)

Rebel Rock : Lynyrd Skynyrd, Normaal, and Regional Identity

NARCIS (Netherlands)

Zwiers, Maarten

2015-01-01

This essay examines the construction of regional identity in the music of two rock bands that became popular during the 1970s: Lynyrd Skynyrd and the Dutch formation Normaal. I discuss the similarities and differences between both bands and analyze the most important sites and characters that appear

Rocking motion of structures under earthquakes. Overturning of 2-DOF system

International Nuclear Information System (INIS)

Kobayashi, Koichi; Watanabe, Tetsuya; Tanaka, Kihachiro; Tomoda, Akinori

2011-01-01

In recent years, huge earthquakes happen, for example, The South Hyogo prefecture Earthquake in 1995, The Mid Niigata Prefecture Earthquake in 2004, The Iwate-Miyagi Nairiku Earthquake in 2008. In The Niigataken Chuetsu-oki Earthquake in 2007, hundreds of drums fell down and water spilled out. A lot of studies about rocking behavior of rigid body had been performed from 1960's. However, these studies were only for a specific condition of the structure size or input vibration characteristics. Therefore, generalizes fall condition for earthquake is required. This paper deals with the analytical and the experimental study of the rocking vibration of 1-DOF rocking system, 2-DOF vibration-rocking system and 2-DOF rocking system under earthquakes. In this study, the equation of motion for each rocking systems are developed. The numerical model of 2-DOF rocking system is evaluated by free rocking experiment. In this paper, 'Overturning Map' which can distinguish whether structures falls or not is proposed. The overturning map of each rocking systems excited by the artificial earthquake wave calculated from the design spectrum is shown. As the result, overturning condition of structures is clarified. (author)

Band-gap and sub-band-gap photoelectrochemical processes at nanocrystalline CdS grown on ZnO by successive ionic layer adsorption and reaction method

International Nuclear Information System (INIS)

Malashchonak, M.V.; Streltsov, E.A.; Mazanik, A.V.; Kulak, A.I.; Poznyak, S.K.; Stroyuk, O.L.; Kuchmiy, S.Ya.; Gaiduk, P.I.

2015-01-01

Cadmium sulfide nanoparticle (NP) deposition by the successive ionic layer adsorption and reaction (SILAR) method on the surface of mesoporous ZnO micro-platelets with a large specific surface area (110 ± 10 m 2 g −1 ) results in the formation of ZnO/CdS heterostructures exhibiting a high incident photon-to-current conversion efficiency (Y) not only within the region of CdS fundamental absorption (Y max = 90%; 0.1 M Na 2 S + 0.1 M Na 2 SO 3 ), but also in the sub-band-gap (SBG) range (Y max = 25%). The onset potentials of SBG photoelectrochemical processes are more positive than the band-gap (BG) onset potential by up to 100 mV. A maximum incident photon-to-current conversion efficiency value for SBG processes is observed at larger amount of deposited CdS in comparison with the case of BG ones. The Urbach energy (E U ) of CdS NPs determined from the photocurrent spectra reaches a maximal value on an early deposition stage (E U = 93 mV at SILAR cycle number N = 5), then lowers somewhat (E U = 73 mV at N = 10) and remains steady in the range of N from 20 to 300 (E U = 67 ± 1 mV). High efficiency of the photoelectrochemical SBG processes are interpreted in terms of light scattering in the ZnO/CdS heterostructures. - Highlights: • ZnO/CdS films demonstrate high quantum efficiency (25%) for sub-band-gap transitions. • Onset photocurrent potentials for sub-band-gap processes differ than those for band-gap ones. • Sub-band-gap transitions are caused by band-tail states in CdS nanoparticles

Band-gap and sub-band-gap photoelectrochemical processes at nanocrystalline CdS grown on ZnO by successive ionic layer adsorption and reaction method

Energy Technology Data Exchange (ETDEWEB)

Malashchonak, M.V., E-mail: che.malasche@gmail.com [Belarusian State University, Nezalezhnastsi Av. 4, Minsk 220030 (Belarus); Streltsov, E.A., E-mail: streltea@bsu.by [Belarusian State University, Nezalezhnastsi Av. 4, Minsk 220030 (Belarus); Mazanik, A.V. [Belarusian State University, Nezalezhnastsi Av. 4, Minsk 220030 (Belarus); Kulak, A.I., E-mail: kulak@igic.bas-net.by [Institute of General and Inorganic Chemistry, National Academy of Sciences of Belarus, Surganova str., 9/1, Minsk 220072 (Belarus); Poznyak, S.K. [Belarusian State University, Nezalezhnastsi Av. 4, Minsk 220030 (Belarus); Stroyuk, O.L., E-mail: stroyuk@inphyschem-nas.kiev.ua [L.V. Pysarzhevsky Institute of Physical Chemistry of National Academy of Sciences of Ukraine, 31 prosp. Nauky, 03028 Kyiv (Ukraine); Kuchmiy, S.Ya. [L.V. Pysarzhevsky Institute of Physical Chemistry of National Academy of Sciences of Ukraine, 31 prosp. Nauky, 03028 Kyiv (Ukraine); Gaiduk, P.I. [Belarusian State University, Nezalezhnastsi Av. 4, Minsk 220030 (Belarus)

2015-08-31

Cadmium sulfide nanoparticle (NP) deposition by the successive ionic layer adsorption and reaction (SILAR) method on the surface of mesoporous ZnO micro-platelets with a large specific surface area (110 ± 10 m{sup 2}g{sup −1}) results in the formation of ZnO/CdS heterostructures exhibiting a high incident photon-to-current conversion efficiency (Y) not only within the region of CdS fundamental absorption (Y{sub max} = 90%; 0.1 M Na{sub 2}S + 0.1 M Na{sub 2}SO{sub 3}), but also in the sub-band-gap (SBG) range (Y{sub max} = 25%). The onset potentials of SBG photoelectrochemical processes are more positive than the band-gap (BG) onset potential by up to 100 mV. A maximum incident photon-to-current conversion efficiency value for SBG processes is observed at larger amount of deposited CdS in comparison with the case of BG ones. The Urbach energy (E{sub U}) of CdS NPs determined from the photocurrent spectra reaches a maximal value on an early deposition stage (E{sub U} = 93 mV at SILAR cycle number N = 5), then lowers somewhat (E{sub U} = 73 mV at N = 10) and remains steady in the range of N from 20 to 300 (E{sub U} = 67 ± 1 mV). High efficiency of the photoelectrochemical SBG processes are interpreted in terms of light scattering in the ZnO/CdS heterostructures. - Highlights: • ZnO/CdS films demonstrate high quantum efficiency (25%) for sub-band-gap transitions. • Onset photocurrent potentials for sub-band-gap processes differ than those for band-gap ones. • Sub-band-gap transitions are caused by band-tail states in CdS nanoparticles.

Oblate L = 1 bands in 194,196-201Pb, and 193Hg

International Nuclear Information System (INIS)

Becker, J.A.; Kuhnert, A.; Stoyer, M.A.; Brinkman, M.J.; Wang, T.F.; Roy, N.; Cizewski, J.A.; Stephens, F.S.; Deleplanque, M.A.; Diamond, R.M.; Azaiez, F.; Macchiavelli, A.O.; Korten, W.; Draper, J.E.; California Univ., Berkeley, CA

1992-11-01

Reports of recent experiments have included observations of regular and irregular bands in neutron deficient Pb isotopes with A=194, 196--201. The bands are populated strongly in HI,xn reactions. The shared characteristics of the bands include: (1) Bandhead energies of few MeV; (2) High bandhead spin; (3) Large alignments; (4) Small dynamic moments of inertia, and (5) Strong L = 1 transitions and weaker L = 2 crossover transitions, with B(Ml/B(E2)) ∼ 20 μ 2 /e 2 b 2 . Lifetimes of band members in the 198 Pb regular band are B(Ml) ∼ 1 W.u., and B(E2) ∼ 10 W.u. (with large errors). These observations are consistent with an interpretation of the regular structures as collective oblate bands with both proton and neutron excitations involved; the closed proton shell at Z = 82 is broken, and coupled to v(i l3/2 ) -n excitations. The irregular structures may correspond to triaxial shapes, with similar orbits involved. A similar structure has been also found in 193 Hg

10 CFR 960.4-2-3 - Rock characteristics.

Science.gov (United States)

2010-01-01

... DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Postclosure Guidelines § 960.4-2-3 Rock characteristics. (a) Qualifying condition. The present and... the waste could significantly decrease the isolation provided by the host rock as compared with pre...

Polarimetric receiver in the forty gigahertz band: new instrument for the Q-U-I joint Tenerife experiment

Science.gov (United States)

Villa, Enrique; Cano, Juan L.; Aja, Beatriz; Terán, J. Vicente; de la Fuente, Luisa; Mediavilla, Ángel; Artal, Eduardo

2018-03-01

This paper describes the analysis, design and characterization of a polarimetric receiver developed for covering the 35 to 47 GHz frequency band in the new instrument aimed at completing the ground-based Q-U-I Joint Tenerife Experiment. This experiment is designed to measure polarization in the Cosmic Microwave Background. The described high frequency instrument is a HEMT-based array composed of 29 pixels. A thorough analysis of the behaviour of the proposed receiver, based on electronic phase switching, is presented for a noise-like linearly polarized input signal, obtaining simultaneously I, Q and U Stokes parameters of the input signal. Wideband subsystems are designed, assembled and characterized for the polarimeter. Their performances are described showing appropriate results within the 35-to-47 GHz frequency band. Functionality tests are performed at room and cryogenic temperatures with adequate results for both temperature conditions, which validate the receiver concept and performance.

Odd - even staggering, a result of γ - band split

International Nuclear Information System (INIS)

Singh, M.; Gupta, D.K.; Singh, Yuvraj; Gupta, K.K.; Bihari, Chhail; Sharma, Aparna; Varshney, A.K.; Varshney, Mani

2011-01-01

The structure of low - lying K = 2+ gamma band in even - even nuclei represents quadrupole vibration breaking axial symmetry in unified collective model of Bohr-Mottelson. In the group theoretical approach of the Interacting boson model (IBM) the band structure can belong to one of the three limiting symmetries of U (6) algebra viz. U (5), SU (3) and O (6), corresponding to the anharmonic vibrator, deformed rotor and γ - unstable respectively

Th and U in the Paleozoic and Mesozoic systems of Kitakami range (preliminary report)

International Nuclear Information System (INIS)

Katada, Masato; Kanaya, Hiroshi; Sato, Choji.

1984-01-01

The research of Th and U in Kitakami range was commenced during the period of late 1950s and early 1960s. Following the exploration, the studies on Th and U in sedimentary rocks in Kitakami have been continued systematically. The data of Th and U covered whole Kitakami range by the addition of the newly obtained analytical data of northern part. The behaviors of Th and U during deposition and their contents in source rocks were studied by the analytical data. 75 samples of mudstone, sandstone, the matrix of conglomerate and limestone from south Kitakami, and 180 samples of mudstone, cherty clay stone, limestone, chert and green rock from northern part of Kitakami were analyzed. U/K 2 O ratio was constant regardless of the stratigraphy in the samples of southern Kitakami. This suggests that the major portion of U was initially dissolved in seawater, adsorbed by sericite, which is the only K 2 O -bearing mineral of sediment, and deposited. The values of Th and U in the sedimentary rocks in southern Kitakami were nearly the same as those of common sedimentary rocks in the world. It is supposed that the formation of K 2 O-bearing mineral was small, and the contents in source rocks affected. On the contrary, the Th values of sedimentary rocks in northern Kitakami, were higher than those of south, and it is supposed that this is attributable to the felsitic nature of source rocks. The mudstone of Matsumae, Hokkaido, differed from that of Kitakami, which means that they were not in same sedimentary basin. (Ishimitsu, A.)

Palaeointensity determinations and magnetic properties on Eocene rocks from Izu-Bonin-Mariana forearc (IODP Exp. 352)

Science.gov (United States)

Carvallo, C.; Camps, P.; Sager, W. W.; Poidras, T.

2017-09-01

IODP Expedition 352 cored igneous rocks from the Izu-Bonin-Mariana forearc crust. Cores from Sites U1440 and U1441 recovered Eocene basalts and related rocks and cores from Sites U1439 and U1442 recovered Eocene boninites and related rocks. We selected samples from Holes U1439C, U1440B and U1442A for palaeointensity measurements. Hysteresis measurements and high and low-temperature magnetization curves show that samples from Hole U1440B undergo magneto-chemical changes when heated and are mostly composed of single-domain (SD) or pseudo-single-domain (PSD) titanomaghemite. In contrast, the same measurements show that most selected samples from Holes U1439C and U1442A are thermally stable and are composed of either SD or PSD titanomagnetite with very little titanium content, or SD ferromagnetic grains with a large paramagnetic contribution. Thellier-Thellier palaeointensity experiments carried out on U1439C and U1442A samples give a good success rate of 25/60 and Virtual Dipole Moment (VDM) values between 1.3 and 3.5 × 1022 Am2. Multispecimen palaeointensity experiments with the domain-state corrected method carried out on 55 samples from Hole U1440B (divided into four groups) and 20 from Hole U1439C gave poor quality results, but indicated a VDM around 4-6 × 1022 Am2 in Hole U1440B forearc basalts. These results are in agreement with the few, low VDM values previously measured on Eocene rocks. However, they do not support an inverse relationship between field intensity and reversal rate for this period of time, since the Eocene reversal rate was low.

The 3 micron ice band

International Nuclear Information System (INIS)

Greenberg, J.M.; Bult, C.E.P.M. van de

1984-01-01

Ever since it was proposed that H 2 O could be a dominant constituent of interstellar grains, its detection, or lack thereof, has played a large role in theories of grains and their evolution. It now appears possible to provide a basic theoretical structure for the evolution of grains in molecular clouds based on current observational evidence and laboratory experiments on the ice band. Both band strengths and shapes can be reasonably predicted by grain models. (U.K.)

TBT recommends : Estonian Music Awards. First Rock'n'Roll Festival. Fantazy

Index Scriptorium Estoniae

2005-01-01

Muusikaauhindade jagamise üritusest 2. märtsil Tallinna klubis Parlament. 26. veebr. rahvusvahelisest Rock'n'Roll Festivalist Lätis (esinevad eesti ansambel Chick'n Band, ansamblid Boogie D, Wildfire Willie & the Ramblers ning läti pianist Pete Anderson). Vodevillide õhtust 25. veebr. klubis "New York" Vilniuses

Triaxial slide-hold-slide shear experiment of sedimentary rock under drain condition

International Nuclear Information System (INIS)

Kishida, Kiyoshi; Yano, Takao; Elsworth, Derek; Yasuhara, Hideaki; Nakashima, Shinichiro

2011-01-01

When discussing the mechanical and hydro-mechanical properties of rock masses under the long-term holding, the variation of rock structure and the change of shear band condition should be discussed in considering the effect of thermal and chemical influences. In this research, the triaxial shear experiment under drain condition was conducted through sedimentary rock, and in the residual stress state, the slide-hold-slide processes were applied to these triaxial experiments. The experiments were carried out in 3 kinds of confining conditions and 2 kinds of thermal conditions. Consequently, the healing phenomena can be observed and the shear strength recovery is also confirmed in process of the holding time. (author)

Popular Music Pedagogy: Band Rehearsals at British Universities

Science.gov (United States)

Pulman, Mark

2014-01-01

There has been little published pedagogical research on popular music group rehearsing. This study explores the perceptions of tutors and student pop/rock bands about the rehearsals in which they were involved as a part of their university music course. The participants were 10 tutors and 16 bands from eight British tertiary institutions. Analysis…

The role of Co impurities and oxygen vacancies in the ferromagnetism of Co-doped SnO2: GGA and GGA+U studies

International Nuclear Information System (INIS)

Wang Hongxia; Yan Yu; Mohammed, Y. Sh.; Du Xiaobo; Li Kai; Jin Hanmin

2009-01-01

The electronic structure and ferromagnetic stability of Co-doped SnO 2 are studied using the first-principle density functional method within the generalized gradient approximation (GGA) and GGA+U schemes. The addition of effective U Co transforms the ground state of Co-doped SnO 2 to insulating from half-metallic and the coupling between the nearest neighbor Co spins to weak antimagnetic from strong ferromagnetic. GGA+U Co calculations show that the pure substitutional Co defects in SnO 2 cannot induce the ferromagnetism. Oxygen vacancies tend to locate near Co atoms. Their presence increases the magnetic moment of Co and induces the ferromagnetic coupling between two Co spins with large Co-Co distance. The calculated density of state and spin density distribution calculated by GGA+U Co show that the long-range ferromagnetic coupling between two Co spins is mediated by spin-split impurity band induced by oxygen vacancies. More charge transfer from impurity to Co-3d states and larger spin split of Co-3d and impurity states induced by the addition of U Co enhance the ferromagnetic stability of the system with oxygen vacancies. By applying a Coulomb U O on O 2 s orbital, the band gap is corrected for all calculations and the conclusions derived from GGA+U Co calculations are not changed by the correction of band gap.

Analysis of Western Australian zebra rock

International Nuclear Information System (INIS)

Clark, M.J.; Cashion, J.D.

2000-01-01

Full text: Zebra rock is a striking rock from the Ord River area of Western Australia which contains regularly spaced white and red-brown bands or rods. Its ease of working has made it popular for use in ornaments and costume jewellery. However, the mechanism for its formation has been a source of controversy for 75 years and is still not settled. Possible mechanisms proposed include slow sedimentation with regular addition of hydrated iron oxides, leaching of a reddish mudstone, post-depositional mobilisation and subsequent rhythmic precipitation of iron oxides from groundwaters, and accumulation of iron-containing minerals in ripple troughs. Loughnan and Roberts suggested a more detailed explanation and from a detailed mineralogical examination, including XRD, XRF, SEM and TEM, they concluded that the only major difference between the two coloured bands was the presence of hematite, α-Fe 2 O 3 . In an attempt to throw more light on the problem, we have taken 57 Fe Moessbauer spectra of samples from the two different coloured regions. As expected, the white coloured material contained little iron, giving a weak, broad single line spectrum at room temperature. At 78 K, the spectrum has split into a magnetic sextet which has not yet been positively identified. As expected from the XRD, the spectrum of the red part principally consists of a strong sextet due to hematite, although there is also a weak component from the phase in the white material. It is hoped that further analysis will help us to eliminate at least some of the proposed mechanisms for the formation of zebra rock

Oxygen isotope studies of early Precambrian granitic rocks from the Giants Range batholith, northeastern Minnesota, U.S.A.

Science.gov (United States)

Viswanathan, S.

1974-01-01

Oxygen isotope studies of granitic rocks from the 2.7 b.y.-old composite Giants Range batholith show that: (1) ??(O18)quartz values of 9 to 10 permil characterize relatively uncontaminated Lower Precambrian, magmatic granodiorites and granites; (2) granitic rocks thought to have formed by static granitization have ??(O18)quartz values that are 1 to 2 permil higher than magmatic granitic rocks; (3) satellite leucogranite bodies have values nearly identical to those of the main intrusive phases even where they transect O18-rich metasedimentary wall rocks; (4) oxygen isotopic interaction between the granitic melts and their O18-rich wall rocks was minimal; and (5) O18/O18 ratios of quartz grains in a metasomatic granite are largely inherited from the precursor rock, but during the progression - sedimentary parent ??? partially granitized parent ??? metasomatic granite ??? there is gradual decrease in ??(O18)quartz by 1 to 2 permil. ?? 1974.

Natural analogue for storage of radwaste in crystalline rocks

International Nuclear Information System (INIS)

Brookins, D.G.; Abashian, M.S.; Cohen, L.H.; Wollenberg, H.A. Jr.

1982-01-01

The Bryan-Eldora stock (Colorado) intruded the Precambrian Idaho Springs Formation metamorphic rocks 58 million years ago. Geochronologic-geochemical work by Hart et al. [S.R. Hart et al., in Radiometric Dating for Geologists, E.I. Hamilton, R.S. Farquhar, eds. (Wiley-Interscience, New York, 1968) pp. 73-110] has demonstrated that the heat from the cooling intrusive rocks was sufficient to affect mineral isotopic systematics up to 2000 m from the contact, and the nature of these isotopic perturbations can be explained by a simple diffusion model in turn based on various heat flow models. Our new studies are focused on elemental exchange between stock and intruded rock as a function of distance from the contact; the assumption is made that the stock is a very large, high heat source analogous to a waste form emplaced in the metamorphic rocks without benefit of canister or engineered backfill. Data for U, Th and the REE indicate actinide and lanthanide immobility except perhaps in the 0 to 2m contact zone where some infiltration of the country rocks by stock-derived fluids occurred. Beyond 4m no stock-derived U, Th, REE or *Pb are noted. Further, whole rock Rb-Sr and stable O isotopic data indicate conductive cooling as opposed to convective, water-induced cooling. The intruded rocks possess low porosity and permeability; this helped prevent elemental migration during the 10 5 to 10 6 years of stock crystallization. The petrographic and geochemical studies show that the Idaho Springs (or equivalent) metamorphic rocks are well suited for radwaste storage. 1 figure, 1 table

Grenville age of basement rocks in Cape May NJ well: New evidence for Laurentian crust in U.S. Atlantic Coastal Plain basement Chesapeake terrane

Science.gov (United States)

Sheridan, R.E.; Maguire, T.J.; Feigenson, M.D.; Patino, L.C.; Volkert, R.A.

1999-01-01

The Chesapeake terrane of the U.S. mid-Atlantic Coastal Plain basement is bounded on the northwest by the Salisbury positive gravity and magnetic anomaly and extends to the southeast as far as the Atlantic coast. It underlies the Coastal Plain of Virginia, Maryland, Delaware and southern New Jersey. Rubidium/Strontium dating of the Chesapeake terrane basement yields an age of 1.025 ?? 0.036 Ga. This age is typical of Grenville province rocks of the Middle to Late Proterozoic Laurentian continent. The basement lithologies are similar to some exposed Grenville-age rocks of the Appalachians. The TiO2 and Zr/P2O5 composition of the metagabbro from the Chesapeake terrane basement is overlapped by those of the Proterozoic mafic dikes in the New Jersey Highlands. These new findings support the interpretation that Laurentian basement extends southeast as far as the continental shelf in the U.S. mid-Atlantic region. The subcrop of Laurentian crust under the mid-Atlantic Coastal Plain implies unroofing by erosion of the younger Carolina (Avalon) supracrustal terrane. Dextral-transpression fault duplexes may have caused excessive uplift in the Salisbury Embayment area during the Alleghanian orogeny. This extra uplift in the Salisbury area may have caused the subsequent greater subsidence of the Coastal Plain basement in the embayment.

Uranium occurrence in major rock types by fission-track mapping

International Nuclear Information System (INIS)

Ledger, E.G.; Bomber, B.J.; Schaftenaar, W.E.; Tieh, T.T.

1984-01-01

Microscopic occurrence of uranium has been determined in about 50 igneous rocks from various location, and in a genetically unrelated sandstone from south Texas. Precambrian granites from the Llano uplift of central Texas contain from a few ppm uranium (considered normal) to over 100 ppm on a whole-rock basis. In granite, uranium is concentrated in: (1) accessory minerals including zircon, biotite, allanite, Fe-Ti oxides, and altered sphene, (2) along grain boundaries and in microfractures by precipitation from deuteric fluids, and (3) as point sources (small inclusions) in quartz and feldspars. Tertiary volcanic rocks from the Davis Mountains of west Texas include diverse rock types from basalt to rhyolite. Average uranium contents increase from 1 ppm in basalts to 7 ppm in rhyolites. Concentration occurs: (1) in iron-titanium-oxides, zircon, and rutile, (2) in the fine-grained groundmass as uniform and point-source concentrations, and (3) as late uranium in cavities associated with banded, silica-rich material. Uranium in ore-grade sandstone is concentrated to more than 3%. Specific occurrences include (1) leucoxene and/or anatase, (2) opaline and calcite cements, (3) mud clasts and altered volcanic rock fragments, and (4) in a few samples, as silt-size uranium- and molybdenum-rich spheres. Uranium content is quite low in pyrite, marcasite, and zeolites

Rock the Globe

CERN Multimedia

Laëtitia Pedroso

2010-01-01

Created in 2005, the Swiss rock band "Wind of Change" is now candidate for the Eurovision Song Contest 2011 with a new song " Night & Light " with the music video filmed at CERN.   With over 20 gigs under their belt and two albums already released, the five members of the band (Alex Büchi, vocals; Arthur Spierer, drums; David Gantner, bass; Romain Mage and Yannick Gaudy, guitar) continue to excite audiences. For their latest composition "Night & Light", the group filmed their music video in the Globe of Science and Innovation. Winning the Eurovision contest would be a springboard in their artistic career for these young musicians. The selection results will be available December 11, 2010.      

Reactivity of micas and cap-rock in wet supercritical CO_2 with SO_2 and O_2 at CO_2 storage conditions

International Nuclear Information System (INIS)

Pearce, Julie K.; Dawson, Grant K.W.; Law, Alison C.K.; Biddle, Dean; Golding, Suzanne D.

2016-01-01

Seal or cap-rock integrity is a safety issue during geological carbon dioxide capture and storage (CCS). Industrial impurities such as SO_2, O_2, and NOx, may be present in CO_2 streams from coal combustion sources. SO_2 and O_2 have been shown recently to influence rock reactivity when dissolved in formation water. Buoyant water-saturated supercritical CO_2 fluid may also come into contact with the base of cap-rock after CO_2 injection. Supercritical fluid-rock reactions have the potential to result in corrosion of reactive minerals in rock, with impurity gases additionally present there is the potential for enhanced reactivity but also favourable mineral precipitation. The first observation of mineral dissolution and precipitation on phyllosilicates and CO_2 storage cap-rock (siliciclastic reservoir) core during water-saturated supercritical CO_2 reactions with industrial impurities SO_2 and O_2 at simulated reservoir conditions is presented. Phyllosilicates (biotite, phlogopite and muscovite) were reacted in contact with a water-saturated supercritical CO_2 containing SO_2, or SO_2 and O_2, and were also immersed in the gas-saturated bulk water. Secondary precipitated sulfate minerals were formed on mineral surfaces concentrated at sheet edges. SO_2 dissolution and oxidation resulted in solution pH decreasing to 0.74 through sulfuric acid formation. Phyllosilicate dissolution released elements to solution with ∼50% Fe mobilized. Geochemical modelling was in good agreement with experimental water chemistry. New minerals nontronite (smectite), hematite, jarosite and goethite were saturated in models. A cap-rock core siltstone sample from the Surat Basin, Australia, was also reacted in water-saturated supercritical CO_2 containing SO_2 or in pure supercritical CO_2. In the presence of SO_2, siderite and ankerite were corroded, and Fe-chlorite altered by the leaching of mainly Fe and Al. Corrosion of micas in the cap-rock was however not observed as the pH was

The U.S. Geological Survey Bird Banding Laboratory: an integrated scientific program supporting research and conservation of North American birds

Science.gov (United States)

Smith, Gregory J.

2013-01-01

The U.S. Geological Survey (USGS) Bird Banding Laboratory (BBL) was established in 1920 after ratification of the Migratory Bird Treaty Act with the United Kingdom in 1918. During World War II, the BBL was moved from Washington, D.C., to what is now the USGS Patuxent Wildlife Research Center (PWRC). The BBL issues permits and bands to permittees to band birds, records bird band recoveries or encounters primarily through telephone and Internet reporting, and manages more than 72 million banding records and more than 4.5 million records of encounters using state-of-the-art technologies. Moreover, the BBL also issues bands and manages banding and encounter data for the Canadian Bird Banding Office (BBO). Each year approximately 1 million bands are shipped from the BBL to banders in the United States and Canada, and nearly 100,000 encounter reports are entered into the BBL systems. Banding data are essential for regulatory programs, especially migratory waterfowl harvest regulations. The USGS BBL works closely with the U.S. Fish and Wildlife Service (USFWS) to develop regulations for the capture, handling, banding, and marking of birds. These regulations are published in the Code of Federal Regulations (CFR). In 2006, the BBL and the USFWS Division of Migratory Bird Management (DMBM) began a comprehensive revision of the banding regulations. The bird banding community has three major constituencies: Federal and State agency personnel involved in the management and conservation of bird populations that include the Flyway Councils, ornithological research scientists, and avocational banders. With increased demand for banding activities and relatively constant funding, a Federal Advisory Committee (Committee) was chartered and reviewed the BBL program in 2005. The final report of the Committee included six major goals and 58 specific recommendations, 47 of which have been addressed by the BBL. Specifically, the Committee recommended the BBL continue to support science

Signature effects in 2-qp rotational bands

International Nuclear Information System (INIS)

Jain, A.K.; Goel, A.

1992-01-01

The authors briefly review the progress in understanding the 2-qp rotational bands in odd-odd nuclei. Signature effects and the phenomenon of signature inversion are discussed. The Coriolis coupling appears to have all the ingredients to explain the inversion. Some recent work on signature dependence in 2-qp bands of even-even nuclei is also discussed; interesting features are pointed out

Current status of crushed rock and whole rock column studies

International Nuclear Information System (INIS)

Vine, E.N.; Daniels, W.R.; Rundberg, R.S.; Thompson, J.L.

1980-01-01

Measurements on a large number of crushed rock columns of tuff, granite, and argillite are discussed. The isotopes 85 Sr, 137 Cs, 133 Ba, 141 Ce, 152 Eu, /sup 95m/Tc, and 233 U were used. Flow rates were varied from approx. 30 to approx. 30000 m/y. Other parameters studied include isotope concentration and atmosphere. The sorption ratios calculated were compared with batch sorption ratios on the same samples. Methods of studying the movement of radionuclides through whole rock cores are described. The problems associated with sealing the cores to prevent leaking along the exterior surface and one possible solution are discussed. The strontium sorption ratio obtained by elution of one solid tuff core is compared with the batch and crushed rock column sorption ratios

Distribution of uranium, thorium and potassium in the alkaline rocks of Pocos de Caldas massif

International Nuclear Information System (INIS)

Rocha, E.B.

1985-01-01

The Pocos de Caldas massif, with area about 800 Km 2 , represents the greatest complex of alkaline rocks existent in the American continent. Although values of U and Th are well Known in the mineralized areas, few has been registered with respect to the distribution of those elements outside the ore deposits. The rocks of the massif, in general, present high contents of U and Th when confronted with the surrouding country rocks. The distribution of the U and Th appoint a relevant additional data in the discussion on the hypothesis of nepheline syenites bodies formation in Pocos de Caldas by crystal fractionation processes. In this work are provided results of the U, Th and K distribution in the main petrographic facies occurring in the several studies places of the massif, yielded by gamma-ray spectrometric analysis of the samples. Those analysis disclose that khibinites present average values about 38 ppm U and 120 ppm Th; lujavrites, about 14 ppm U and more than 70 ppm Th; U-Th depleted nepheline synites, about 12 ppm U and 38 ppm Th, Th/U ratios are close to 3,0 in the nepheline syenites, about 3,7 in the phonolites, reaching values close to 4,0 in the khibinites. These values are comparable with others Th/U ratios of selected series of alkaline rocks reported in the international literature. Uranium and Th comparative data, attained by delayed neutron counting activation analysis also are given. The results obtained for the fluorimetric analysis show loss of U leaching is greater in the fine-grained rocks (phonolites) than coarse-grained ones (lujavrites, Khibinites). The autoradiographic studies reveal that radioactive elements are found concentrated in mineral phases. A new assessment of the radiogenic heat production it is also available. (Author) [pt

Effect of inhibition of the ROCK isoform on RT2 malignant glioma cells.

Science.gov (United States)

Inaba, Nobuharu; Ishizawa, Sho; Kimura, Masaki; Fujioka, Kouki; Watanabe, Michiko; Shibasaki, Toshiaki; Manome, Yoshinobu

2010-09-01

Malignant glioma is one of the most intractable diseases in the human body. Rho-kinase (ROCK) is overexpressed and has been proposed as the main cause for the refractoriness of the disease. Since efficacious treatment is required, this study investigated the effect of inhibition of ROCK isoforms. The short hairpin RNA transcription vector was transfected into the RT2 rat glioma cell line and the characteristics of the cells were investigated. The effect of nimustine hydrochloride (ACNU) anti-neoplastic agent on cells was also measured. Inhibition of ROCK isoforms did not alter cell growth. Cell cycle analysis revealed that ROCK1 down-regulation reduced the G(0) phase population and ROCK2 down-regulation reduced the G(2)/M phase population. When ROCK1-down-regulated cells were exposed to ACNU, they demonstrated susceptibility to the agent. The roles of ROCK1 and ROCK2 may be different in glioma cells. Furthermore, the combination of ROCK1 down-regulation and an anti-neoplastic agent may be useful for the therapy of malignant glioma.

New kind of radioactive inclusions in igneous rocks

Energy Technology Data Exchange (ETDEWEB)

Coppens, R

1949-06-20

In previous notes (Compt. rend 228, 176 and 1218(1949)) two sorts of radioactive inclusions in igneous rocks, as recorded on photographic plates, were described: (1) very small (several microns) and strongly radioactive inclusions containing U and Th, (2) crystals of undertermined species, about 1 mm large, containing about 1% Th, and no U. The present note is a report on a third kind of inclusions, observed in a sand from Brittany and in a granite: having an area of several hundredths of mm/sup 2/, they are strongly radioactive; they contain Th, but little or no U; the Th content, which is about 76%, corresponds to pure thorite ThO/sub 2/.SiO/sub 2/.

Structural observations and U-Pb mineral ages from igneous rocks at the Archaean-Palaeoproterozoic boundary in the Salahmi Schist Belt, central Finland: constraints on tectonic evolution

Directory of Open Access Journals (Sweden)

Pietikäinen, K.

1999-06-01

Full Text Available The study area in Vieremä, central Finland, contains part of Archaean-Palaeoproterozoic boundary. In the east, the area comprises Archaean gneiss and the Salahmi Schist Belt. The rocks of the schist belt are turbiditic metagreywackes, with well-preserved depositional structures, occurring as Proterozoic wedge-shaped blocks, and staurolite schists, the latter representing higher-strained and metamorphosed equivalents of the metagreywackes. In the west of the area there is an Archaean gneiss block, containing strongly elongated structures, and deformed Svecofennian supracrustal rocks, which are cut by deformed granitoids. These are juxtaposed with the schist belt. The boundaries of these tectonometamorphic blocks are narrow, highly strained mylonites and thrust zones. The metamorphic grade of the supracrustal rocks increases from east to west, the increase being stepwise across the mylonitic block boundaries. The rocks are more deformed from east to west with younger structures overprinting. In the staurolite schists of the Salahmi Schist Belt, the most prominent structure is a lineation (L2 that overprints the bedding and axial plane foliation. In Sorronmäki quarry, at the western boundary of the schist belt, this Palaeoproterozoic lineation dominates all the structures in tonalite gneiss, which gives a U-Pb age of 2731±6 Ma. Southeast of the quarry, at the same boundary, the Salahmi schists have been overturned towards the northeast, suggesting that the Archaean gneiss at Sorronmäki has been thrust towards the northeast over these rocks. In the western part of the study area, the Leppikangas granodiorite that intrudes the Svecofennian supracrustal rocks gives a U-Pb age of 1891+6 Ma. In the granodiorite, a strong lineation formed by the intersection of two foliations, which maybe L2 is associated with thrusting towards the northeast. The monazite age of the Archaean Sorronmäki gneiss is 1817+3 Ma, and the titanite age of the Svecofennian

Near-edge band structures and band gaps of Cu-based semiconductors predicted by the modified Becke-Johnson potential plus an on-site Coulomb U

International Nuclear Information System (INIS)

Zhang, Yubo; Zhang, Jiawei; Wang, Youwei; Gao, Weiwei; Abtew, Tesfaye A.; Zhang, Peihong; Zhang, Wenqing

2013-01-01

Diamond-like Cu-based multinary semiconductors are a rich family of materials that hold promise in a wide range of applications. Unfortunately, accurate theoretical understanding of the electronic properties of these materials is hindered by the involvement of Cu d electrons. Density functional theory (DFT) based calculations using the local density approximation or generalized gradient approximation often give qualitative wrong electronic properties of these materials, especially for narrow-gap systems. The modified Becke-Johnson (mBJ) method has been shown to be a promising alternative to more elaborate theory such as the GW approximation for fast materials screening and predictions. However, straightforward applications of the mBJ method to these materials still encounter significant difficulties because of the insufficient treatment of the localized d electrons. We show that combining the promise of mBJ potential and the spirit of the well-established DFT + U method leads to a much improved description of the electronic structures, including the most challenging narrow-gap systems. A survey of the band gaps of about 20 Cu-based semiconductors calculated using the mBJ + U method shows that the results agree with reliable values to within ±0.2 eV

A feasibility study of U-Pb and Pb-Pb dating of kimberlites using groundmass mineral fractions and whole-rock samples

International Nuclear Information System (INIS)

Kramers, J.D.; Smith, C.B.

1983-01-01

This paper describes partly successful attempts to determine emplacement ages of kimberlites by U-Pb and Pb-Pb methods involving groundmass minerals with high U content (notably perovskite) and whole-rock kimberlite samples. U/Pb ratios in perovskite in the matrix of kimberlites can be two orders of magnitude larger than in the rest of the kimberlite material, and with simple mineral separation techniques moderate success was achieved in U-Pb dating of fresh samples of younger kimberlites (around 100 Ma). The differences in U/Pb ratios between kimberlite samples from different parts of the same pipe have also been found to be large enough, in some cases, to allow reasonably accurate U-Pb age determination. In older kimberlites the U-Pb ages obtained were mostly imcompatible with geological constraints and results obtained by other methods. However, for such pipes use of Pb-Pb systematics yields realistic age limits in some cases

Research on supplying potential of uranium source from rocks in western provenance area of Hailaer basin

International Nuclear Information System (INIS)

Xia Yuliang; Liu Hanbin; Chinese Academy of Geological Sciences, Beijing

2006-01-01

Using U-Pb isotope composition evolution, this paper expounds the initial uranium content in volcanic rocks of provenance area of Xihulitu basin and in granites of provenance area of Kelulun sag, western Hailaer basin. The initial uranium content (U 0 ) in volcanic rocks of provenance area is higher, the average initial uranium content of volcanic rocks is 10.061 x 10 -6 , the average uranium variation coefficient (ΔU) is -49.57%; the average initial uranium content of granites is 18.381 x 10 -6 , the average uranium variation coefficient (ΔU) is -80%. The results indicate that rocks in provenance area could provide the pre-enrichment of uranium in deposited sandstone. U-Ra equilibrium coefficients of rocks indicate that there is obvious U-Ra disequilibrium phenomenon in volcanic rocks, and the time when granites provided uranium source occurred 16000 a ago. (authors)

CO2-Water-Rock Wettability: Variability, Influencing Factors, and Implications for CO2 Geostorage.

Science.gov (United States)

Iglauer, Stefan

2017-05-16

Carbon geosequestration (CGS) has been identified as a key technology to reduce anthropogenic greenhouse gas emissions and thus significantly mitigate climate change. In CGS, CO 2 is captured from large point-source emitters (e.g., coal fired power stations), purified, and injected deep underground into geological formations for disposal. However, the CO 2 has a lower density than the resident formation brine and thus migrates upward due to buoyancy forces. To prevent the CO 2 from leaking back to the surface, four trapping mechanisms are used: (1) structural trapping (where a tight caprock acts as a seal barrier through which the CO 2 cannot percolate), (2) residual trapping (where the CO 2 plume is split into many micrometer-sized bubbles, which are immobilized by capillary forces in the pore network of the rock), (3) dissolution trapping (where CO 2 dissolves in the formation brine and sinks deep into the reservoir due to a slight increase in brine density), and (4) mineral trapping (where the CO 2 introduced into the subsurface chemically reacts with the formation brine or reservoir rock or both to form solid precipitates). The efficiency of these trapping mechanisms and the movement of CO 2 through the rock are strongly influenced by the CO 2 -brine-rock wettability (mainly due to the small capillary-like pores in the rock which form a complex network), and it is thus of key importance to rigorously understand CO 2 -wettability. In this context, a substantial number of experiments have been conducted from which several conclusions can be drawn: of prime importance is the rock surface chemistry, and hydrophilic surfaces are water-wet while hydrophobic surfaces are CO 2 -wet. Note that CO 2 -wet surfaces dramatically reduce CO 2 storage capacities. Furthermore, increasing pressure, salinity, or dissolved ion valency increases CO 2 -wettability, while the effect of temperature is not well understood. Indeed theoretical understanding of CO 2 -wettability and the

Tank 241-U-102, Grab Samples 2U-99-1, 2U-99-2 and 2U-99-3 Analytical Results for the Final Report

International Nuclear Information System (INIS)

STEEN, F.H.

1999-01-01

This document is the final report for tank 241-U-102 grab samples. Five grab samples were collected from riser 13 on May 26, 1999 and received by the 222-S laboratory on May 26 and May 27, 1999. Samples 2U-99-3 and 2U-99-4 were submitted to the Process Chemistry Laboratory for special studies. Samples 2U-99-1, 2U-99-2 and 2U-99-5 were submitted to the laboratory for analyses. Analyses were performed in accordance with the Compatibility Grab Sampling and Analysis Plan for Fiscal year 1999 (TSAP) (Sasaki, 1999) and the Data Quality Objectives for Tank Farms Waste Compatibility Program (DQO) (Fowler 1995, Mulkey and Miller 1998). The analytical results are presented in the data summary report. None of the subsamples submitted for differential scanning calorimetry (DSC), total organic carbon (TOC) and plutonium 239 (Pu239) analyses exceeded the notification limits as stated in TSAP

Development of a mixed seawater-hydrothermal fluid geochemical signature during alteration of volcanic rocks in the Archean (∼2.7 Ga) Abitibi Greenstone Belt, Canada

Science.gov (United States)

Brengman, Latisha A.; Fedo, Christopher M.

2018-04-01

We investigated a group of silicified volcanic rocks from the ∼2.72 Ga Hunter Mine Group (HMG), Abitibi Greenstone Belt, Canada, in order to document progressive compositional change associated with alteration in a subaqueous caldera system. Rocks of the HMG divide into three groups based on mineralogy and texture for petrographic and geochemical analyses. Volcanic features (phenocrysts, pseudomorphs after primary glass shards, lapilli, volcanic clasts) are preserved in all groups, despite changing mineralogy from primarily quartz, feldspar, chlorite (Groups 1 and 2), to quartz, hematite and carbonate (Groups 2 and 3). Compositionally, Group 1 rocks resemble volcanic rocks in the region, while Group 2 and 3 rocks show a change in mineralogy to iron, silica, and carbonate minerals, which is associated with depletion of many major and trace elements associated with volcanic rocks (Al2O3, Na2O, K2O, Zr). In addition, rare earth elements display a clear progression from volcanic signatures in Group 1 (PrSN/YbSN = 1.7-2.96, EuSN/EuSN∗ = 0.84-1.72, Y/Ho = 25.20-27.41, LaSN/LaSN∗ = 0.97-1.29, and Zr/Hf = 38.38-42.09) to transitional mixed volcanic, hydrothermal, and seawater signatures in Group 2 (PrSN/YbSN 1.33-2.89, EuSN/EuSN∗ 1.33-2.5, Y/Ho = 23.94-30, LaSN/LaSN∗ 0.93-1.34, and Zr/Hf = 40-70), to mixed hydrothermal and seawater signatures in Group 3 (PrSN/YbSN 0.62-2.88, EuSN/EuSN∗ 1.30-7.15, LaSN/LaSN∗ 1.02-1.86, Y/Ho = 25.56-55, and Zr/Hf = 35-50). We interpret that silicification of volcanic rocks (Group 1) produced transitional altered volcanic rocks (Group 2), and siliceous and jaspilitic rocks (Group 3), based on preservation of delicate volcanic features. Building on this explanation, we interpret that major, trace- and rare-earth element mobility occurred during the process of silicification, during which siliceous and jaspilitic rocks (Group 3) acquired aspects of the rare-earth element geochemical signatures of marine chemical precipitates. We

GGA+U study on phase transition, optoelectronic and magnetic properties of AmO{sub 2} with spin–orbit coupling

Energy Technology Data Exchange (ETDEWEB)

Bendjedid, A.; Seddik, T. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 (Algeria); Baltache, H. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 (Algeria); Murtaza, G., E-mail: murtaza@icp.edu.pk [Materials Modeling Laboratory, Department of Physics, Islamia College University, Peshawar (Pakistan); Bouhemadou, A. [Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, University of Setif, 19000 Setif (Algeria); Bin Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Azam, Sikander; Khan, Saleem Ayaz [New Technologies-Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic)

2015-12-15

In this work, we have investigated the structural, phase transition, optoelectronic and magnetic properties of AmO{sub 2} using the full potential linearized augmented plane wave plus local orbital (FP-LAPW+lo) method. The exchange-correlation potential was treated with the generalized gradient approximation (GGA). Moreover, the GGA+U approximation (where U denotes the Hubbard Coulomb energy U term) is employed to treat the f electrons properly. The structurally stable AmO{sub 2} compound is the Fm3m phase and at a pressure between 40 and 60 GPa underwent a phase transition to the Pnma phase. Our present calculations have considered ferromagnetic and simple antiferromagnetic ground states and the AF state is favored. However, the experimental situation suggests a complex magnetic structure, perhaps involving multipolar ordering. Our band structure calculation with GGA and GGA+U predicted the metallic behavior of AmO{sub 2}; however, with the spin–orbit coupling (SOC) added to the Coulomb energy U term, semiconducting ground states with antiferromagnetism is correctly predicted. The projected density of states from the energy-band structure indicates that the band gap opening is governed by the partially filled Am “5f” state, and the calculated gap is approximately 1.29 eV. Moreover, the optical properties reveal strong response of AmO{sub 2} in the UV region. - Highlights: • AmO{sub 2} is antiferromagnetic and stable in the Fm3m phase under ambient conditions. • It makes structural transition from the Fm3m to the Pnma phase at 55.91 GPa. • Columbic repulsion parameter U correctly predicted the electronic state of AmO{sub 2}. • This compound absorbs strongly in the UV region.

Change in cap rock porosity triggered by pressure and temperature dependent CO2–water–rock interactions in CO2 storage systems

Directory of Open Access Journals (Sweden)

Christina Hemme

2017-03-01

Full Text Available Carbon capture and storage in deep geological formations is a method to reduce greenhouse gas emissions. Supercritical CO2 is injected into a reservoir and dissolves in the brine. Under the impact of pressure and temperature (P–T the aqueous species of the CO2-acidified brine diffuse through the cap rock where they trigger CO2–water–rock interactions. These geochemical reactions result in mineral dissolution and precipitation along the CO2 migration path and are responsible for a change in porosity and therefore for the sealing capacity of the cap rock. This study focuses on the diffusive mass transport of CO2 along a gradient of decreasing P–T conditions. The process is retraced with a one-dimensional hydrogeochemical reactive mass transport model. The semi-generic hydrogeochemical model is based on chemical equilibrium thermodynamics. Based on a broad variety of scenarios, including different initial mineralogical, chemical and physical parameters, the hydrogeochemical parameters that are most sensitive for safe long-term CO2 storage are identified. The results demonstrate that P–T conditions have the strongest effect on the change in porosity and the effect of both is stronger at high P–T conditions because the solubility of the mineral phases involved depends on P–T conditions. Furthermore, modeling results indicate that the change in porosity depends strongly on the initial mineralogical composition of the reservoir and cap rock as well as on the brine compositions. Nevertheless, a wide range of conditions for safe CO2 storage is identified.

Geochemistry, Radioactivity and Gamma-Ray Dose Assesment of Igneous Rocks, of Abu El Hassan El Aswad Area, North Egypt Eastern Desert

International Nuclear Information System (INIS)

Abdel-Monem, A.A.; Moussa, E.M.; Abd El Fattah, M.M.G.; Wetait, M.A.

2011-01-01

Abu El Hassan Al Aswad area, Northern Eastern Desert, Egypt, is located between lat. 26 degree 45/ and 26 degree 58 / N and long. 33 degree 0/ and 33 degree 11 /50// E, covering approximately 270 km 2 . It is covered by a suite of igneous rocks, which are classified according to their silica and potash contents into ultra basic rock class with the least silica and potash contents, basic rock class, intermediated rock class and acidic rock class with the highest silica and potash contents. The ultra basic rocks with SiO 2 2 (42-57%), K (0.15-0.5), U (0.8-3 ppm) and Th (1-7 ppm), produce the gamma ray doses (AEDE, 0.266 mSv/y; AGDE, 0.1475 mSv/y). The intermediate rocks with SiO 2 (57-65%), K (0-8-2.5%), U (2-8 ppm) and Th (3.5-14.5 ppm) produce the gamma ray doses (AEDE, 0.083 mSv/y; AGDE, 0.4784 mSv/y). The acidic rocks with SiO 2 (65-75%), K (2.6-4.3%), U (4.5-10 ppm) and Th (13-26 ppm) produce the gamma ray doses (AEDE, 0.1692 mSv/y; AGDE, 0.9571 mSv/y).It is suggested that the ultra basic, basic and the intermediated rock classes can be used safely as building materials as well as for indoor and outdoor decorations. The acidic rock class may be used for outdoor decorations but not as building materials or indoor decoration due to its high AGDE values, which when added to the other gamma ray exposure source may exceed the International Accepted Radiation Dose Limit to member of the public which is (1-3 mSv/y)

Electron microprobe analyses of selected samples from deep rock disposal experiment No. 1

International Nuclear Information System (INIS)

Hlava, P.F.; Chambers, W.F.

1976-04-01

Deep Rock Disposal Experiment No. 1 was designed to provide information about the interaction between a molten, glass-based, nuclear waste simulant and rock material. Selected samples from this experiment were examined by optical microscopy and electron probe microanalysis. Analysis of the homogenized material in the convection cell that was created in the central portion of the melt region shows that an amount of rock equal to about one-half of the original amount of waste simulant was incorporated in the melt during the experiment. Stagnant melt at the sides of the cell formed a glass with large compositional gradients. A white band separated the convected and stagnant materials. The color of the band is attributed to light scattering by small crystallites formed during cooling. Four types of crystallites grew from the melt: two oxides, a Mg--Fe borate, and a silicate. Spinel (MgO, Cr 2 O 3 , FeO (Fe 2 O 3 ), and NiO) was the most common crystallite in the glass. The spinel crystallites found within the convection cell displayed skeletal morphology and oscillatory zoning which indicates growth at varying temperatures as they were carried along by convection. A single cluster of nonskeletal (Fe,Cr) 2 O 3 crystallites was found at the bottom of the melt zone where convection did not occur. Mg--Fe borate crystallites grew in clusters in the central portion of the convection cell after convection ceased. A silicate similar to Fe-rich diopside (CaMgSi 2 O 6 ) with unusual amounts of Ce 2 O 3 and other heavy metal oxides formed as larger crystallites in the stagnant melt at the side of the convection cell and as many very small crystallites in the white band

On the CO2 Wettability of Reservoir Rocks: Addressing Conflicting Information

Science.gov (United States)

Garing, C.; Wang, S.; Tokunaga, T. K.; Wan, J.; Benson, S. M.

2017-12-01

Conventional wisdom is that siliclastic rocks are strongly water wet for the CO2-brine system, leading to high irreducible water saturation, moderate residual gas trapping and implying that tight rocks provide efficient seals for buoyant CO2. If the wetting properties become intermediate or CO2 wet, the conclusions regarding CO2 flow and trapping could be very different. Addressing the CO2 wettability of seal and reservoir rocks is therefore essential to predict CO2 storage in geologic formation. Although a substantial amount of work has been dedicated to the topic, contact angle data show a large variability and experiments on plates, micromodels and cores report conflicting results regarding the influence of supercritical CO2 (scCO2) exposure on wetting properties: whereas some experimental studies suggest dewetting upon reaction with scCO2, some others observe no wettability alteration under reservoir scCO2 conditions. After reviewing evidences for and against wettability changes associated with scCO2, we discuss potential causes for differences in experimental results. They include the presence of organic matter and impact of sample treatment, the type of media (non consolidated versus real rock), experimental time and exposure to scCO2, and difference in measurement system (porous plate versus stationary fluid method). In order to address these points, new scCO2/brine drainage-imbibition experiments were conducted on a same Berea sandstone rock core, first untreated, then fired and finally exposed to scCO2 for three weeks, using the stationary fluid method. The results are compared to similar experiments performed on quartz sands, untreated and then baked, using the porous plate method. In addition, a comparative experiment using the same Idaho gray sandstone rock core was performed with both the porous plate and the stationary fluid methods to investigate possible method-dependent results.

Drill-back studies examine fractured, heated rock

International Nuclear Information System (INIS)

Wollenberg, H.A.; Flexser, S.; Myer, L.R.

1990-01-01

To investigate the effects of heating on the mineralogical, geochemical, and mechanical properties of rock by high-level radioactive waste, cores are being examined from holes penetrating locations where electric heaters simulated the presence of a waste canister, and from holes penetration natural hydrothermal systems. Results to date indicate the localized mobility and deposition of uranium in an open fracture in heated granitic rock, the mobility of U in a breccia zone in an active hydrothermal system in tuff, and the presence of U in relatively high concentration in fracture-lining material in tuff. Mechanical -- property studies indicate that differences in compressional- and shear-wave parameters between heated and less heated rock can be attributed to differences in the density of microcracks. Emphasis has shifted from initial studies of granitic rock at Stripa, Sweden to current investigations of welded tuff at the Nevada Test Site. 7 refs., 8 figs

Assessment of natural radioactivity levels in rocks and their relationships with the geological structure of Johor state, Malaysia.

Science.gov (United States)

Alnour, I A; Wagiran, H; Ibrahim, N; Hamzah, S; Elias, M S; Laili, Z; Omar, M

2014-01-01

The distribution of natural radionuclides ((238)U, (232)Th and (40)K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of (238)U, (232)Th and (40)K activity concentrations (67±6, 85±7 and 722±18 Bg kg(-1), respectively) were observed in the granite rock. The lowest concentrations of (238)U and (232)Th (2±0.1 Bq kg(-1) for (238)U and 2±0.1 Bq kg(-1) for (232)Th) were observed in gabbro rock. The lowest concentration of (40)K (45±2 Bq kg(-1)) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg(-1). The highest value of radium equivalent in the present study (239±17 Bq kg(-1)) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h(-1). The effective dose ranged from 5 to 138 μSv h(-1). The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed.

Absolute linestrengths in the H2O2 nu6 band

Science.gov (United States)

May, Randy D.

1991-01-01

Absolute linestrengths at 295 K have been measured for selected lines in the nu6 band of H2O2 using a tunable diode-laser spectrometer. H2O2 concentrations in a flowing gas mixture were determined by ultraviolet (uv) absorption at 254 nm using a collinear infrared (ir) and uv optical arrangement. The measured linestrengths are approx. 60 percent larger than previously reported values when absorption by hot bands in H2O2 is taken into account.

Predicting rock bursts in mines

Science.gov (United States)

Spall, H.

1979-01-01

In terms of lives lost, rock bursts in underground mines can be as hazardous as earthquakes on the surface. So it is not surprising that fo the last 40 years the U.S Bureau of Mines has been using seismic methods for detecting areas in underground mines where there is a high differential stress which could lead to structural instability of the rock mass being excavated.

Bibliography for acid-rock drainage and selected acid-mine drainage issues related to acid-rock drainage from transportation activities

Science.gov (United States)

Bradley, Michael W.; Worland, Scott C.

2015-01-01

Acid-rock drainage occurs through the interaction of rainfall on pyrite-bearing formations. When pyrite (FeS2) is exposed to oxygen and water in mine workings or roadcuts, the mineral decomposes and sulfur may react to form sulfuric acid, which often results in environmental problems and potential damage to the transportation infrastructure. The accelerated oxidation of pyrite and other sulfidic minerals generates low pH water with potentially high concentrations of trace metals. Much attention has been given to contamination arising from acid mine drainage, but studies related to acid-rock drainage from road construction are relatively limited. The U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, is conducting an investigation to evaluate the occurrence and processes controlling acid-rock drainage and contaminant transport from roadcuts in Tennessee. The basic components of acid-rock drainage resulting from transportation activities are described and a bibliography, organized by relevant categories (remediation, geochemical, microbial, biological impact, and secondary mineralization) is presented.

Crustal contamination versus an enriched mantle source for intracontinental mafic rocks: Insights from early Paleozoic mafic rocks of the South China Block

Science.gov (United States)

Xu, Wenjing; Xu, Xisheng; Zeng, Gang

2017-08-01

Several recent studies have documented that the silicic rocks (SiO2 > 65 wt.%) comprising Silicic Large Igneous Provinces are derived from partial melting of the crust facilitated by underplating/intraplating of "hidden" large igneous province-scale basaltic magmas. The early Paleozoic intracontinental magmatic rocks in the South China Block (SCB) are dominantly granitoids, which cover a combined area of 22,000 km2. In contrast, exposures of mafic rocks total only 45 km2. These mafic rocks have extremely heterogeneous isotopic signatures that range from depleted to enriched (whole rock initial 87Sr/86Sr = 0.7041-0.7102; εNd(t) = - 8.4 to + 1.8; weighted mean zircon εHf(t) = - 7.4 to + 5.2), show low Ce/Pb and Nb/U ratios (0.59-13.1 and 3.5-20.9, respectively), and variable Th/La ratios (0.11-0.51). The high-MgO mafic rocks (MgO > 10 wt.%) tend to have lower εNd(t) values (- 4) and Sm/Nd ratios (> 0.255). The differences in geochemistry between the high-MgO and low-MgO mafic rocks indicate greater modification of the compositions of high-MgO mafic magmas by crustal material. In addition, generally good negative correlations between εNd(t) and initial 87Sr/86Sr ratios, MgO, and K2O, along with the presence of inherited zircons in some plutons, indicate that the geochemical and isotopic compositions of the mafic rocks reflect significant crustal contamination, rather than an enriched mantle source. The results show that high-MgO mafic rocks with fertile isotopic compositions may be indicative of crustal contamination in addition to an enriched mantle source, and it is more likely that the lithospheric mantle beneath the SCB during the early Paleozoic was moderately depleted than enriched by ancient subduction processes.

Quasiparticle band structure for the Hubbard systems: Application to α-CeAl2

International Nuclear Information System (INIS)

Costa-Quintana, J.; Lopez-Aguilar, F.; Balle, S.; Salvador, R.

1990-01-01

A self-energy formalism for determining the quasiparticle band structure of the Hubbard systems is deduced. The self-energy is obtained from the dynamically screened Coulomb interaction whose bare value is the correlation energy U. A method for integrating the Schroedingerlike equation with the self-energy operator is given. The method is applied to the cubic Laves phase of α-CeAl 2 because it is a clear Hubbard system with a very complex electronic structure and, moreover, this system provides us with sufficient experimental data for testing our method

Ring complexes and related rocks in Africa

Science.gov (United States)

Vail, J. R.

Over 625 igneous complexes throughout Africa and Arabia have been selected and classified on the basis of petrographic association and chronology into six broad age groups forming 29 provinces. The groups range from Mid-Proterozoic to Tertiary and include gabbro, granite, syenite, foid syenite and carbonatite plutonic rocks, the majority in the form of ring-dykes, cone-sheets, plugs, circular intrusions, and their associated extrusive phases. Pan-African late or post-orogenic complexes (720-490 Ma) are common in the Arabian-Nubian and Tuareg shields of north Africa originating from subduction zone derived magmatism. Anorogenic complexes in Egypt, NE and central Sudan, Niger, Nigeria, Cameroon, Zaïre-Burundi, Malawi, Mozambique, Zimbabwe, Namibia and Angola span 550 to 50 Ma and are dominantly alkali granites and foid syenites. Many groups occur as en-echelon bands within linear arrays, and show migrating centres of intrusion in variable directions. In W. Africa there was a progressive shift of emplacement southwards during early Ordovician to Mid-Cretaceous times. Distribution patterns suggest thatdeep seated features, such as shear zones associated with lithospheric plate movements,controlled melting, and the resultant location of the complexes. Economic mineralization is not widespread in the rocks of the African ring complexes and is mainly restricted to small deposits of Sn, W, F, U and Nb.

New uranium chalcoantimonates, RbU{sub 2}SbS{sub 8} and KU{sub 2}SbSe{sub 8}, with a polar noncentrosymmetric structure

Energy Technology Data Exchange (ETDEWEB)

Choi, K S; Kanatzidis, M G

1999-09-01

The new compounds, RbU{sub 2}SbS{sub 8} and KU{sub 2}SbSe{sub 8}, were prepared as golden-black, blocklike crystals by the polychalcogenide molten flux method. RbU{sub 2}SbS{sub 8} has a two-dimensional character with layers running perpendicular to the c-axis. The coordination geometry around the U{sup 4+} atoms is best described as a bicapped trigonal prism. The trigonal prisms share triangular faces with neighboring prisms, forming one-dimensional columns along the a-axis. The columns are then joined to construct sheets by sharing capping S atoms. Sb{sup 3+} ions are sitting at the center of a slightly distorted seesaw coordination environment (CN = 4). Rb{sup +} ions are stabilized in 8-coordinate bicapped trigonal prismatic sites. KU{sub 2}SbSe{sub 8} has essentially the same structure as RbU{sub 2}SbS{sub 8}. However, Sb{sup 3+} and K{sup +} ions appear disordered in every other layer resulting in a different unit cell. RbU{sub 2}SbS{sub 8} is a semiconductor with a band gap of 1.38 eV. The band gap of KU{sub 2}SbSe{sub 8} could not be determined precisely due to the presence of overlapping intense f-f transitions in the region (0.5--1.1 eV). The Raman spectra show the disulfide stretching vibration in RbU{sub 2}SbS{sub 8} at 479 cm{sup {minus}1} and the diselenide stretching vibration in KU{sub 2}SbSe{sub 8} at 252 cm{sup {minus}1}. Magnetic susceptibility measurements indicate the presence of U{sup 4+} centers in the compounds. The compounds do not melt below 1,000 C under vacuum.

Preliminary state-of-the-art survey: mining techniques for salt and other rock types

Energy Technology Data Exchange (ETDEWEB)

1976-12-01

This is a systematic review of the state-of-the-art of underground mining and excavation technology in the U.S. as applied to salt, limestone, shale, and granite. Chapter 2 covers the basic characteristics of these rock types, the most frequently used underground mining methods, shaft and slope entry construction, equipment, and safety and productivity data. Chapters 3 and 4 summarize underground salt and limestone mining in the U.S. Chapter 5 shows that large amounts of thick shale exist in the U.S., but little is mined. Chapter 6 discusses underground excavations into granite-type rocks. Suggestions are given in the last chapter for further study. (DLC)

Band Alignment at GaN/Single-Layer WSe2 Interface

KAUST Repository

Tangi, Malleswararao

2017-02-21

We study the band discontinuity at the GaN/single-layer (SL) WSe2 heterointerface. The GaN thin layer is epitaxially grown by molecular beam epitaxy on chemically vapor deposited SL-WSe2/c-sapphire. We confirm that the WSe2 was formed as an SL from structural and optical analyses using atomic force microscopy, scanning transmission electron microscopy, micro-Raman, absorbance, and microphotoluminescence spectra. The determination of band offset parameters at the GaN/SL-WSe2 heterojunction is obtained by high-resolution X-ray photoelectron spectroscopy, electron affinities, and the electronic bandgap values of SL-WSe2 and GaN. The valence band and conduction band offset values are determined to be 2.25 ± 0.15 and 0.80 ± 0.15 eV, respectively, with type II band alignment. The band alignment parameters determined here provide a route toward the integration of group III nitride semiconducting materials with transition metal dichalcogenides (TMDs) for designing and modeling of their heterojunction-based electronic and optoelectronic devices.

Band Alignment at GaN/Single-Layer WSe2 Interface

KAUST Repository

Tangi, Malleswararao; Mishra, Pawan; Tseng, Chien-Chih; Ng, Tien Khee; Hedhili, Mohamed N.; Anjum, Dalaver H.; Alias, Mohd Sharizal; Wei, Nini; Li, Lain-Jong; Ooi, Boon S.

2017-01-01

We study the band discontinuity at the GaN/single-layer (SL) WSe2 heterointerface. The GaN thin layer is epitaxially grown by molecular beam epitaxy on chemically vapor deposited SL-WSe2/c-sapphire. We confirm that the WSe2 was formed as an SL from structural and optical analyses using atomic force microscopy, scanning transmission electron microscopy, micro-Raman, absorbance, and microphotoluminescence spectra. The determination of band offset parameters at the GaN/SL-WSe2 heterojunction is obtained by high-resolution X-ray photoelectron spectroscopy, electron affinities, and the electronic bandgap values of SL-WSe2 and GaN. The valence band and conduction band offset values are determined to be 2.25 ± 0.15 and 0.80 ± 0.15 eV, respectively, with type II band alignment. The band alignment parameters determined here provide a route toward the integration of group III nitride semiconducting materials with transition metal dichalcogenides (TMDs) for designing and modeling of their heterojunction-based electronic and optoelectronic devices.

Radwaste storage in crystalline rocks: a natural analog

International Nuclear Information System (INIS)

Brookins, D.G.; Abashian, M.S.; Cohen, L.H.; Wollenberg, H.A.

1982-01-01

The Eldora-Bryan Stock (Colorado) intruded the 1.4-1.6 billion year old metamorphic rocks of the Idaho Springs Formation 55 million years ago. The stock may be considered a giant analog of a radwaste form without canister or engineered backfill barriers. The authors' lanthanide studies show the following: (1) The intrusive rocks remained as a closed system. (2) Lanthanide/chondrite versus ionic radius plots show only local redistribution in the immediate contact zone, and that rocks in this zone have not gained lanthanides from the magma. (3) No whole rock perturbations for the lanthanides are noted at distances greater than 3 m from the contact. Stable oxygen isotopic variations show a narrow 9.0 +- 0.3 per mille range for the intrusive rocks and whole rock values from 7.6 to 10.0 per mille for the intruded rocks. The authors conclude: (1) The Idaho Springs Formation was not penetrated by hydrothermal fluids from the Eldora-Bryan magma except possibly on a local scale within 3 m of the contact. (2) The light lanthanides may be locally redistributed in the immediate contact zone, but without additions from the magma. (3) The oxygen isotopic data imply lack of hydrothermal fluids from the magma penetrating the intruded rocks, even in the highest temperature contact zones. Whole rock data imply closed system conditions for Rb, Sr, Th, U, Pb even where mineral ages have been lowered. Data for Co, Cr, Sc, Fe, Cs also indicate retention in whole rock systems and no exchange with the magma. The combined chemical, isotopic, petrographic and theoretical data and calculations indicate suitability of rocks of the Idaho Springs Formation, and thus of many types of crystalline rocks as well, for possible use for the storage of radioactive waste

Life on rock. Scaling down biological weathering in a new experimental design at Biosphere-2

Science.gov (United States)

Zaharescu, D. G.; Dontsova, K.; Burghelea, C. I.; Chorover, J.; Maier, R.; Perdrial, J. N.

2012-12-01

Biological colonization and weathering of bedrock on Earth is a major driver of landscape and ecosystem development, its effects reaching out into other major systems such climate and geochemical cycles of elements. In order to understand how microbe-plant-mycorrhizae communities interact with bedrock in the first phases of mineral weathering we developed a novel experimental design in the Desert Biome at Biosphere-2, University of Arizona (U.S.A). This presentation will focus on the development of the experimental setup. Briefly, six enclosed modules were designed to hold 288 experimental columns that will accommodate 4 rock types and 6 biological treatments. Each module is developed on 3 levels. A lower volume, able to withstand the weight of both, rock material and the rest of the structure, accommodates the sampling elements. A middle volume, houses the experimental columns in a dark chamber. A clear, upper section forms the habitat exposed to sunlight. This volume is completely sealed form exterior and it allows a complete control of its air and water parameters. All modules are connected in parallel with a double air purification system that delivers a permanent air flow. This setup is expected to provide a model experiment, able to test important processes in the interaction rock-life at grain-to- molecular scale.

Band-engineering of TiO2 as a wide-band gap semiconductor using organic chromophore dyes

Science.gov (United States)

Wahyuningsih, S.; Kartini, I.; Ramelan, A. H.; Saputri, L. N. M. Z.; Munawaroh, H.

2017-07-01

Bond-engineering as applied to semiconductor materials refers to the manipulation of the energy bands in order to control charge transfer processes in a device. When the device in question is a photoelectrochemical cell, the charges affected by drift become the focus of the study. The ideal band gap of semiconductors for enhancement of photocatalyst activity can be lowered to match with visible light absorption and the location of conduction Band (CB) should be raised to meet the reducing capacity. Otherwise, by the addition of the chromofor organic dyes, the wide-band gab can be influences by interacation resulting between TiO2 surface and the dyes. We have done the impruvisation wide-band gap of TiO2 by the addition of organic chromophore dye, and the addition of transition metal dopand. The TiO2 morphology influence the light absorption as well as the surface modification. The organic chromophore dye was syntesized by formation complexes compound of Co(PAR)(SiPA)(PAR)= 4-(2-piridylazoresorcinol), SiPA = Silyl propil amine). The result showed that the chromophore groups adsorbed onto TiO2 surface can increase the visible light absorption of wide-band gab semiconductor. Initial absorption of a chromophore will affect light penetration into the material surfaces. The use of photonic material as a solar cell shows this phenomenon clearly from the IPCE (incident photon to current conversion efficiency) measurement data. Organic chromophore dyes of Co(PAR)(SiPA) exhibited the long wavelength absorption character compared to the N719 dye (from Dyesol).

Band structures of 4f and 5f materials studied by angle-resolved photoelectron spectroscopy.

Science.gov (United States)

Fujimori, Shin-ichi

2016-04-20

Recent remarkable progress in angle-resolved photoelectron spectroscopy (ARPES) has enabled the direct observation of the band structures of 4f and 5f materials. In particular, ARPES with various light sources such as lasers (hν ~ 7 eV) or high-energy synchrotron radiations (hν >/~ 400 eV) has shed light on the bulk band structures of strongly correlated materials with energy scales of a few millielectronvolts to several electronvolts. The purpose of this paper is to summarize the behaviors of 4f and 5f band structures of various rare-earth and actinide materials observed by modern ARPES techniques, and understand how they can be described using various theoretical frameworks. For 4f-electron materials, ARPES studies of CeMIn5(M = Rh, Ir, and Co) and YbRh2Si2 with various incident photon energies are summarized. We demonstrate that their 4f electronic structures are essentially described within the framework of the periodic Anderson model, and that the band-structure calculation based on the local density approximation cannot explain their low-energy electronic structures. Meanwhile, electronic structures of 5f materials exhibit wide varieties ranging from itinerant to localized states. For itinerant U5f compounds such as UFeGa5, their electronic structures can be well-described by the band-structure calculation assuming that all U5f electrons are itinerant. In contrast, the band structures of localized U5f compounds such as UPd3 and UO2 are essentially explained by the localized model that treats U5f electrons as localized core states. In regards to heavy fermion U-based compounds such as the hidden-order compound URu2Si2, their electronic structures exhibit complex behaviors. Their overall band structures are generally well-explained by the band-structure calculation, whereas the states in the vicinity of EF show some deviations due to electron correlation effects. Furthermore, the electronic structures of URu2Si2 in the paramagnetic and hidden-order phases are

Investigation on acceptable reverberation time at various frequency bands in halls that present amplified music

DEFF Research Database (Denmark)

Adelman-Larsen, Niels Werner; Jeong, Cheol-Ho; Støfringsdal, Bård

2018-01-01

Subjective ratings from 25 professional musicians and sound engineers were obtained to assess two Danish rock venues of similar size and similar low frequency reverberation times, but different high frequency reverberation times. The musicians judged one hall significantly better than the other......, confirming a hypothesis that rock venues can have a longer reverberation time at mid to high frequencies at least in the empty condition. A fairly long reverberation time in the 63 Hz octave band is found to be acceptable, so the 125 Hz octave band is probably the single most important band to control...... for amplified music....

NONLINEAR COLOR-METALLICITY RELATIONS OF GLOBULAR CLUSTERS. II. A TEST ON THE NONLINEARITY SCENARIO FOR COLOR BIMODALITY USING THE u-BAND COLORS: THE CASE OF M87 (NGC 4486)

International Nuclear Information System (INIS)

Yoon, Suk-Jin; Lee, Sang-Yoon; Kim, Hak-Sub; Cho, Jaeil; Chung, Chul; Sohn, Sangmo T.; Blakeslee, John P.

2011-01-01

The optical color distributions of globular clusters (GCs) in most large elliptical galaxies are bimodal. Based on the assumed linear relationship between GC colors and their metallicities, the bimodality has been taken as evidence of two GC subsystems with different metallicities in each galaxy and has led to a number of theories in the context of galaxy formation. More recent observations and modeling of GCs, however, suggests that the color-metallicity relations (CMRs) are inflected, and thus colors likely trace metallicities in a nonlinear manner. The nonlinearity could produce bimodal color distributions from a broad underlying metallicity spread, even if it is unimodal. Despite the far-reaching implications, whether CMRs are nonlinear and whether the nonlinearity indeed causes the color bimodality are still open questions. Given that the spectroscopic refinement of CMRs is still very challenging, we here propose a new photometric technique to probe the possible nonlinear nature of CMRs. In essence, a color distribution of GCs is a 'projected' distribution of their metallicities. Since the form of CMRs hinges on which color is used, the shape of color distributions varies depending significantly on the colors. Among other optical colors, the u-band related colors (e.g., u – g and u – z) are theoretically predicted to exhibit significantly less inflected CMRs than other preferred CMRs (e.g., for g – z). As a case study, we performed the Hubble Space Telescope (HST)/WFPC2 archival u-band photometry for the M87 (NGC 4486) GC system with confirmed color bimodality. We show that the u-band color distributions are significantly different from that of g – z and consistent with our model predictions. With more u-band measurements, this method will support or rule out the nonlinear CMR scenario for the origin of GC color bimodality with high confidence. The HST/WFC3 observations in F336W for nearby large elliptical galaxies are highly anticipated in this regard.

Bioremediation in fractured rock: 2. Mobilization of chloroethene compounds from the rock matrix

Science.gov (United States)

Shapiro, Allen M.; Tiedeman, Claire; Imbrigiotta, Thomas; Goode, Daniel J.; Hsieh, Paul A.; Lacombe, Pierre; DeFlaun, Mary F.; Drew, Scott R.; Curtis, Gary P.

2018-01-01

A mass balance is formulated to evaluate the mobilization of chlorinated ethene compounds (CE) from the rock matrix of a fractured mudstone aquifer under pre- and postbioremediation conditions. The analysis relies on a sparse number of monitoring locations and is constrained by a detailed description of the groundwater flow regime. Groundwater flow modeling developed under the site characterization identified groundwater fluxes to formulate the CE mass balance in the rock volume exposed to the injected remediation amendments. Differences in the CE fluxes into and out of the rock volume identify the total CE mobilized from diffusion, desorption, and nonaqueous phase liquid dissolution under pre- and postinjection conditions. The initial CE mass in the rock matrix prior to remediation is estimated using analyses of CE in rock core. The CE mass mobilized per year under preinjection conditions is small relative to the total CE mass in the rock, indicating that current pump-and-treat and natural attenuation conditions are likely to require hundreds of years to achieve groundwater concentrations that meet regulatory guidelines. The postinjection CE mobilization rate increased by approximately an order of magnitude over the 5 years of monitoring after the amendment injection. This rate is likely to decrease and additional remediation applications over several decades would still be needed to reduce CE mass in the rock matrix to levels where groundwater concentrations in fractures achieve regulatory standards.

Assessing hydraulic connections across a complex sequence of volcanic rocks - Analysis of U-20 WW multiple-well aquifer test, Pahute Mesa, Nevada National Security Site, Nevada

Science.gov (United States)

Garcia, C. Amanda; Fenelon, Joseph M.; Halford, Keith J.; Reiner, Steven R.; Laczniak, Randell J.

2011-01-01

Groundwater beneath Pahute Mesa flows through a complexly layered sequence of volcanic rock aquifers and confining units that have been faulted into distinct structural blocks. Hydraulic property estimates of rocks and structures in this flow system are necessary to assess radionuclide migration near underground nuclear testing areas. The U.S. Geological Survey (USGS) used a 12 month (October 1, 2008— October 1, 2009) intermittent pumping schedule of well U-20 WW and continuously monitored water levels in observation wells ER-20-6 #3, UE-20bh 1, and U-20bg as a multi-well aquifer test to evaluate hydraulic connections across structural blocks, bulk hydraulic properties of volcanic rocks, and the hydraulic significance of a major fault. Measured water levels were approximated using synthetic water levels generated from an analytical model. Synthetic water levels are a summation of environmental water-level fluctuations and a Theis (1935) transform of the pumping signal from flow rate to water-level change. Drawdown was estimated by summing residual differences between measured and synthetic water levels and the Theis-transformed pumping signal from April to September 2009. Drawdown estimates were used in a three‑dimensional numerical model to estimate hydraulic properties of distinct aquifers, confining units, and a major fault.

Electronic band structure study of colossal magnetoresistance in Tl 2Mn 2O 7

Science.gov (United States)

Seo, D.-K.; Whangbo, M.-H.; Subramanian, M. A.

1997-02-01

The electronic structure of Tl 2Mn 2O 7 was examined by performing tight binding band calculations. The overlap between the Mn t 2g- and Tl 6 s-block bands results in a partial filling of the Tl 6 s-block bands. The associated Fermi surface consists of 12 cigar-shape electron pockets with each electron pocket about {1}/{1000} of the first Brillouin zone in size. The Tl 6 s-block bands have orbital contributions from the Mn atoms, and the carrier density is very low. These are important for the occurrence of a colossal magnetoresistance in Tl 2Mn 2O 7.

U-Pb ages and Hf isotope compositions of zircons in plutonic rocks from the central Famatinian arc, Argentina

Science.gov (United States)

Otamendi, Juan E.; Ducea, Mihai N.; Cristofolini, Eber A.; Tibaldi, Alina M.; Camilletti, Giuliano C.; Bergantz, George W.

2017-07-01

The Famatinian arc formed around the South Iapetus rim during the Ordovician, when oceanic lithosphere subducted beneath the West Gondwana margin. We present combined in situ U-Th-Pb and Lu-Hf isotope analyses for zircon to gain insights into the origin and evolution of Famatinian magmatism. Zircon crystals sampled from four intermediate and silicic plutonic rocks confirm previous observations showing that voluminous magmatism took place during a relatively short pulse between the Early and Middle Ordovician (472-465 Ma). The entire zircon population for the four plutonic rocks yields coherent εHf negative values and spreads over several ranges of initial εHf(t) units (-0.3 to -8.0). The range of εHf units in detrital zircons of Famatinian metasedimentary rocks reflects a prolonged history of the cratonic sources during the Proterozoic to the earliest Phanerozoic. Typical tonalites and granodiorites that contain zircons with evolved Hf isotopic compositions formed upon incorporating (meta)sedimentary materials into calc-alkaline metaluminous magmas. The evolved Hf isotope ratios of zircons in the subduction related plutonic rocks strongly reflect the Hf isotopic character of the metasedimentary contaminant, even though the linked differentiation and growth of the Famatinian arc crust was driven by ascending and evolving mantle magmas. Geochronology and Hf isotope systematics in plutonic zircons allow us understanding the petrogenesis of igneous series and the provenance of magma sources. However, these data could be inadequate for computing model ages and supporting models of crustal evolution.

Water - rock interaction in different rock environments

International Nuclear Information System (INIS)

Lamminen, S.

1995-01-01

The study assesses the groundwater geochemistry and geological environment of 44 study sites for radioactive waste disposal. Initially, the study sites were divided by rock type into 5 groups: (1) acid - intermediate rocks, (2) mafic - ultramafic rocks, (3) gabbros, amphibolites and gneisses that contain calc-silicate (skarn) rocks, (4) carbonates and (5) sandstones. Separate assessments are made of acid - intermediate plutonic rocks and of a subgroup that comprises migmatites, granite and mica gneiss. These all belong to the group of acid - intermediate rocks. Within the mafic -ultramafic rock group, a subgroup that comprises mafic - ultramafic plutonic rocks, serpentinites, mafic - ultramafic volcanic rocks and volcanic - sedimentary schists is also evaluated separately. Bedrock groundwaters are classified by their concentration of total dissolved solids as fresh, brackish, saline, strongly saline and brine-class groundwaters. (75 refs., 24 figs., 3 tabs.)

Empirical optimization of DFT  +  U and HSE for the band structure of ZnO

Science.gov (United States)

Bashyal, Keshab; Pyles, Christopher K.; Afroosheh, Sajjad; Lamichhane, Aneer; Zayak, Alexey T.

2018-02-01

ZnO is a well-known wide band gap semiconductor with promising potential for applications in optoelectronics, transparent electronics, and spintronics. Computational simulations based on the density functional theory (DFT) play an important role in the research of ZnO, but the standard functionals, like Perdew-Burke-Erzenhof, result in largely underestimated values of the band gap and the binding energies of the Zn3d electrons. Methods like DFT  +  U and hybrid functionals are meant to remedy the weaknesses of plain DFT. However, both methods are not parameter-free. Direct comparison with experimental data is the best way to optimize the computational parameters. X-ray photoemission spectroscopy (XPS) is commonly considered as a benchmark for the computed electronic densities of states. In this work, both DFT  +  U and HSE methods were parametrized to fit almost exactly the binding energies of electrons in ZnO obtained by XPS. The optimized parameterizations of DFT  +  U and HSE lead to significantly worse results in reproducing the ion-clamped static dielectric tensor, compared to standard high-level calculations, including GW, which in turn yield a perfect match for the dielectric tensor. The failure of our XPS-based optimization reveals the fact that XPS does not report the ground state electronic structure for ZnO and should not be used for benchmarking ground state electronic structure calculations.

The effective stress concept in a jointed rock mass. A literature survey

International Nuclear Information System (INIS)

Olsson, Roger

1997-04-01

The effective stress concept was defined by Terzaghi in 1923 and was introduced 1936 in a conference at Harvard University. The concept has under a long time been used in soil mechanics to analyse deformations and strength in soils. The effective stress σ' is equal to the total stress σ minus the pore pressure u (σ'=σ-u). The concepts's validity in a jointed rock mass has been investigated by few authors. A literature review of the area has examined many areas to create an overview of the use of the concept. Many rock mechanics and rock engineering books recommend that the expression introduced by Terzaghi is suitable for practical purpose in rock. Nevertheless, it is not really clear if they mean rock or rock mass. Within other areas such as porous rocks, mechanical compressive tests on rock joints and determination of the permeability, a slightly changed expression is used, which reduces the acting pore pressure (σ'=σ-α·u). The α factor can vary between 0 and 1 and is defined differently for different areas. Under assumption that the pore system of the rock mass is sufficiently interconnected, the most relevant expression for a jointed rock mass, that for low effective stresses should the Terzagi's original expression with α=1 be used. But for high normal stresses should α=0.9 be used

ONKALO rock mechanics model (RMM) - Version 2.0

International Nuclear Information System (INIS)

Moenkkoenen, H.; Hakala, M.; Paananen, M.; Laine, E.

2012-02-01

The Rock Mechanics Model of the ONKALO rock volume is a description of the significant features and parameters related to rock mechanics. The main objective is to develop a tool to predict the rock properties, quality and hence the potential for stress failure which can then be used for continuing design of the ONKALO and the repository. This is the second implementation of the Rock Mechanics Model and it includes sub-models of the intact rock strength, in situ stress, thermal properties, rock mass quality and properties of the brittle deformation zones. Because of the varying quantities of available data for the different parameters, the types of presentations also vary: some data sets can be presented in the style of a 3D block model but, in other cases, a single distribution represents the whole rock volume hosting the ONKALO. (orig.)

Band structure of metallic pyrochlore ruthenates Bi2Ru2O7 and Pb2Ru2O/sub 6.5/

International Nuclear Information System (INIS)

Hsu, W.Y.; Kasowski, R.V.; Miller, T.; Chiang, T.

1988-01-01

The band structure of Bi 2 Ru 2 O 7 and Pb 2 Ru 2 O/sub 6.5/ has been computed self-consistently from first principles for the first time by the pseudofunction method. We discover that the 6s bands of Bi and Pb are very deep and unlikely to contribute to the metallic behavior as previously believed. The unoccupied 6p bands, however, are only several eV above the Fermi energy and are mixed with the Ru 4d band at the Fermi surface via the framework O atoms, leading to band conduction and delocalized magnetic moments. The predicted location of the 6s bands and the location and width of the O 2p band are confirmed by synchrotron radiation and ultraviolet electron spectroscopy of single crystals

The Wall-Rock Record of Incremental Emplacement in the Little Cottonwood-Alta Magmatic and Hydrothermal System, Wasatch Mountains, Utah, U.S.A.

Science.gov (United States)

Stearns, M.; Callis, S.; Beno, C.; Bowman, J. R.; Bartley, J. M.

2017-12-01

Contact aureoles record the cumulative effects on wall rocks of magma emplacement. Like the plutons they surround, contact aureoles have long been regarded to form geologically instantaneously. Protracted incremental emplacement of plutons must be reconciled with the wall-rock record of heat and mass transfer. Fundamental questions include how heat and material move from intrusions into their aureoles and how long that process takes. The Little Cottonwood stock is surrounded by a 2 km-wide contact aureole that contains prograde AFM mineral assemblages in the pelitic layers of the Proterozoic Big Cottonwood Formation. The Alta stock is surrounded by a well characterized 1 km-wide contact aureole containing both prograde AFM and CMS mineral assemblages in Ophir Shale and Mississippian dolostones, respectively. Understanding the petrogenesis of these aureoles requires the timing of magmatism and wall-rock metamorphism to be independently determined. Preliminary petrochronology (U/Th-Pb dates and trace element concentrations collected by LASS-ICP-MS) from the inner aureoles of both intrusions establishes a protracted history of monazite (re)crystallization from 35-25 Ma in the Little Cottonwood aureole and 35 Ma in the Alta aureole. Little Cottonwood aureole monazites are characterized by a positive age correlation with heavy rare earth elements (HREE) and a negative correlation with Eu/Eu*. Alta aureole monazites have a similar range of the HREE concentrations and Eu/Eu* variation. Zircon growth interpreted to record emplacement-level magmatic crystallization of the western Little Cottonwood stock ranges from 33-28 Ma near the contact. Multi-grain U-Pb zircon TIMS dates from the Alta stock range from 35-33 Ma and are interpreted to suggest the full range of emplacement-level magmatism in the Alta stock. Additionally, in situ U-Pb titanite dates from the Alta stock record intermittent high temperature hydrothermal activity in the stock margin from 35-24 Ma. These new

Band gap depiction of quaternary FeMnTiAl alloy using Hubbard (U) potential

Science.gov (United States)

Bhat, Tahir Mohiuddin; Yousuf, Saleem; Khandy, Shakeel Ahmad; Gupta, Dinesh C.

2018-05-01

We have employed self-consistent ab-initio calculations to investigate new quaternary alloy FeMnTiAl by applying Hubbard potential (U). The alloy is found to be stable in ferromagnetic phase with cubic structure. The alloy shows half-metallic (HM) ferromagnet character. The values of minority band gap FeMnTiAl are found to be 0.33 eV respectively. Electronic charge density reveals that both types of bonds covalent as well as ionic are present in the alloy. Thus the new quaternary alloy can be proved as vital contender for spin valves and spin generator devices.

U-Pb zircon and biostratigraphic data of high-pressure/low-temperature metamorphic rocks of the Talea Ori: tracking the Paleotethys suture in central Crete, Greece

Science.gov (United States)

Zulauf, G.; Dörr, W.; Krahl, J.; Lahaye, Y.; Chatzaras, V.; Xypolias, P.

2016-10-01

Inherited deformation microfabrics of detrital quartz grains and U-Pb (Laser ablation (LA)-ICPMS and ID TIMS) ages of detrital zircons separated from the Phyllite-Quartzite Unit s.l. of the Talea Ori, central Crete, suggest strikingly different source rocks. Albite gneiss of the lower Rogdia Beds includes Cambrian and Neoproterozoic rounded zircons with main U-Pb age peaks at 628 and 988 Ma. These and minor Paleoproterozoic and Archean peaks, together with the lack of Variscan-aged and Mesoproterozoic zircons, are similar to the age spectra obtained from the Phyllite-Quartzite Unit s.str. of the Peloponnesus and eastern Crete and from the Taurides. All of these zircons should be derived from the northeastern passive margin of Gondwana (Cimmeria). Metatuffites of the uppermost Rogdia Beds and metasandstone of Bali beach, on the other hand, include euhedral detrital zircons displaying a Variscan U-Pb age spectra at ca. 300 Ma with concordia ages at 291 ± 3, 300 ± 1 Ma (Rogdia) and 286 ± 3, 300 ± 3, 313 ± 2 Ma (Bali). Both types of metasediments and their zircons are similar to those of the pre-Alpine basement and overlying Tyros Beds of eastern Crete, revealing a provenance at the southern active margin of Laurasia. Thus, in central Crete the Paleotethys suture should be situated inside the Rogdia Beds. Magmatic zircons separated from a rhyolite boulder of the lower Achlada Beds yielded a concordant U-Pb zircon age at 242 ± 2 Ma placing a maximum age for the deposition of the (meta)conglomerate from which the boulder was collected. This age is compatible with an Olenekian-early Anisian age of the underlying Vasilikon marble suggested by new findings of the foraminifera Meandrospira aff. pusilla. Both the Achlada Beds and the Vasilikon marble can be attributed to the lower Tyros Beds of eastern Crete. The Alpine deformation led to a pervasive mylonitic foliation, which is affecting most of the studied rocks. This foliation results from D2 top

Bioremediation in Fractured Rock: 2. Mobilization of Chloroethene Compounds from the Rock Matrix.

Science.gov (United States)

Shapiro, Allen M; Tiedeman, Claire R; Imbrigiotta, Thomas E; Goode, Daniel J; Hsieh, Paul A; Lacombe, Pierre J; DeFlaun, Mary F; Drew, Scott R; Curtis, Gary P

2018-03-01

A mass balance is formulated to evaluate the mobilization of chlorinated ethene compounds (CE) from the rock matrix of a fractured mudstone aquifer under pre- and postbioremediation conditions. The analysis relies on a sparse number of monitoring locations and is constrained by a detailed description of the groundwater flow regime. Groundwater flow modeling developed under the site characterization identified groundwater fluxes to formulate the CE mass balance in the rock volume exposed to the injected remediation amendments. Differences in the CE fluxes into and out of the rock volume identify the total CE mobilized from diffusion, desorption, and nonaqueous phase liquid dissolution under pre- and postinjection conditions. The initial CE mass in the rock matrix prior to remediation is estimated using analyses of CE in rock core. The CE mass mobilized per year under preinjection conditions is small relative to the total CE mass in the rock, indicating that current pump-and-treat and natural attenuation conditions are likely to require hundreds of years to achieve groundwater concentrations that meet regulatory guidelines. The postinjection CE mobilization rate increased by approximately an order of magnitude over the 5 years of monitoring after the amendment injection. This rate is likely to decrease and additional remediation applications over several decades would still be needed to reduce CE mass in the rock matrix to levels where groundwater concentrations in fractures achieve regulatory standards. © 2017, National Ground Water Association.

Geologic Map of the House Rock Valley Area, Coconino County, Northern Arizona

Science.gov (United States)

Billingsley, George H.; Priest, Susan S.

2010-01-01

This geologic map is a cooperative effort of the U.S. Geological Survey (USGS), the Bureau of Land Management, the National Park Service, and the U.S. Forest Service to provide a geologic database for resource management officials and visitor information services. This map was produced in response to information needs related to a proposed withdrawal of three segregated land areas near Grand Canyon National Park, Arizona, from new hard rock mining activity. House Rock Valley was designated as the east parcel of the segregated lands near the Grand Canyon. This map was needed to provide connectivity for the geologic framework of the Grand Canyon segregated land areas. This geologic map of the House Rock Valley area encompasses approximately 280 mi2 (85.4 km2) within Coconino County, northern Arizona, and is bounded by longitude 111 degrees 37'30' to 112 degrees 05' W. and latitude 36 degrees 30' to 36 degrees 50' N. The map area is in the eastern part of the Arizona Strip, which lies within the southern Colorado Plateaus geologic province (herein Colorado Plateau). The Arizona Strip is the part of Arizona lying north of the Colorado River. The map is bound on the east by the Colorado River in Marble Canyon within Grand Canyon National Park and Glen Canyon National Recreation Area, on the south and west by the Kaibab National Forest and Grand Canyon National Game Preserve, and on the north by the Vermilion Cliffs Natural Area, the Paria Canyon Vermilion Cliffs Wilderness Area, and the Vermilion Cliffs National Monument. House Rock State Buffalo Ranch also bounds the southern edge of the map area. The Bureau of Land Management Arizona Field Office in St. George, Utah, manages public lands of the Vermilion Cliffs Natural Area, Paria Canyon - Vermilion Cliffs Wilderness and Vermilion Cliffs National Monument. The North Kaibab Ranger District in Fredonia, Arizona, manages U.S. Forest Service land along the west edge of the map area and House Rock State Buffalo Ranch

Uranium in alkaline rocks

Energy Technology Data Exchange (ETDEWEB)

Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

1978-04-01

Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential.

Uranium in alkaline rocks

International Nuclear Information System (INIS)

Murphy, M.; Wollenberg, H.; Strisower, B.; Bowman, H.; Flexser, S.; Carmichael, I.

1978-04-01

Geologic and geochemical criteria were developed for the occurrence of economic uranium deposits in alkaline igneous rocks. A literature search, a limited chemical analytical program, and visits to three prominent alkaline-rock localities (Ilimaussaq, Greenland; Pocos de Caldas, Brazil; and Powderhorn, Colorado) were made to establish criteria to determine if a site had some uranium resource potential. From the literature, four alkaline-intrusive occurrences of differing character were identified as type-localities for uranium mineralization, and the important aspects of these localities were described. These characteristics were used to categorize and evaluate U.S. occurrences. The literature search disclosed 69 U.S. sites, encompassing nepheline syenite, alkaline granite, and carbonatite. It was possible to compare two-thirds of these sites to the type localities. A ranking system identified ten of the sites as most likely to have uranium resource potential

Infrared radiation parameterizations for the minor CO2 bands and for several CFC bands in the window region

Science.gov (United States)

Kratz, David P.; Chou, Ming-Dah; Yan, Michael M.-H.

1993-01-01

Fast and accurate parameterizations have been developed for the transmission functions of the CO2 9.4- and 10.4-micron bands, as well as the CFC-11, CFC-12, and CFC-22 bands located in the 8-12-micron region. The parameterizations are based on line-by-line calculations of transmission functions for the CO2 bands and on high spectral resolution laboratory measurements of the absorption coefficients for the CFC bands. Also developed are the parameterizations for the H2O transmission functions for the corresponding spectral bands. Compared to the high-resolution calculations, fluxes at the tropopause computed with the parameterizations are accurate to within 10 percent when overlapping of gas absorptions within a band is taken into account. For individual gas absorption, the accuracy is of order 0-2 percent. The climatic effects of these trace gases have been studied using a zonally averaged multilayer energy balance model, which includes seasonal cycles and a simplified deep ocean. With the trace gas abundances taken to follow the Intergovernmental Panel on Climate Change Low Emissions 'B' scenario, the transient response of the surface temperature is simulated for the period 1900-2060.

Re-appraisal of the Santa Rita Greenstone Belt stratigraphy, central Brazil, based on new U-Pb SHRIMP age and Sm-Nd data of felsic metavolcanic rocks

International Nuclear Information System (INIS)

Pimentel, Marcio Martins; Jost, Hardy; Fuck, Reinhardt Adolfo; Junges, Sergio Luiz; Armstrong, Richard; Resende, Marcelo Goncalves

2000-01-01

The Santa Rita greenstone belt represents one of the supracrustal belts of the Archaen terranes of Goias, central Brazil. The stratigraphic sequence of this greenstone belt comprises a lower of komatities and basalts and an upper metasedimentary unit made of carbonaceous schits, chert, iron formation and marble, unconformably overlain by clastic metasedimentary rocks. Felsic metavolcanics occur at the interface between the metabasalts and the upper metasedimentary pile. U-Pb SHRIMP age for zircons from the felsic metavolcanics reveal that it is not part of the Archaean sequence, but represents the product of mesoproterozoic (1580 ± 12 Ma) magmatic event. Sm-Nd isotopic data (initial e CHUR values between -10.5 and -14.9) and T DM values of 3.0 and 3.2 Ga, within the range of the surrounding TTG terranes, indicate that the original felsic magmas were produced by re-melting of Archaen crust. The data demonstrate that the Goias greenstone belt contains infolded and imbricated proterozoic rocks, as previously suggested by Sm-Nd isotopic analyses of some of the upper detrital metasedimentary rocks. (author)

Re-appraisal of the Santa Rita Greenstone Belt stratigraphy, central Brazil, based on new U-Pb SHRIMP age and Sm-Nd data of felsic metavolcanic rocks

Energy Technology Data Exchange (ETDEWEB)

Pimentel, Marcio Martins; Jost, Hardy; Fuck, Reinhardt Adolfo; Junges, Sergio Luiz [Brasilia Univ., DF (Brazil). Inst. de Geociencias]. E-mail: marcio@unb.br; Armstrong, Richard [Australian National Univ., Canberra, ACT (Australia). Research School of Earth Sciences; Resende, Marcelo Goncalves [Universidade Catolica de Brasilia, DF (Brazil). Curso de Graduacao em Engenharia Ambiental

2000-03-01

The Santa Rita greenstone belt represents one of the supracrustal belts of the Archaen terranes of Goias, central Brazil. The stratigraphic sequence of this greenstone belt comprises a lower of komatities and basalts and an upper metasedimentary unit made of carbonaceous schits, chert, iron formation and marble, unconformably overlain by clastic metasedimentary rocks. Felsic metavolcanics occur at the interface between the metabasalts and the upper metasedimentary pile. U-Pb SHRIMP age for zircons from the felsic metavolcanics reveal that it is not part of the Archaean sequence, but represents the product of mesoproterozoic (1580 {+-} 12 Ma) magmatic event. Sm-Nd isotopic data (initial e{sub CHUR} values between -10.5 and -14.9) and T{sub DM} values of 3.0 and 3.2 Ga, within the range of the surrounding TTG terranes, indicate that the original felsic magmas were produced by re-melting of Archaen crust. The data demonstrate that the Goias greenstone belt contains infolded and imbricated proterozoic rocks, as previously suggested by Sm-Nd isotopic analyses of some of the upper detrital metasedimentary rocks. (author)

Bands dispersion and charge transfer in β-BeH2

Science.gov (United States)

Trivedi, D. K.; Galav, K. L.; Joshi, K. B.

2018-04-01

Predictive capabilities of ab-initio method are utilised to explore bands dispersion and charge transfer in β-BeH2. Investigations are carried out using the linear combination of atomic orbitals method at the level of density functional theory. The crystal structure and related parameters are settled by coupling total energy calculations with the Murnaghan equation of state. Electronic bands dispersion from PBE-GGA is reported. The PBE-GGA, and PBE0 hybrid functional, show that β-BeH2 is a direct gap semiconductor with 1.18 and 2.40 eV band gap. The band gap slowly decreases with pressure and beyond l00 GPa overlap of conduction and valence bands at the r point is observed. Charge transfer is studied by means of Mullikan population analysis.

CERN Rocks

CERN Multimedia

2004-01-01

The 15th CERN Hardronic Festival took place on 17 July on the terrace of Rest 3 (Prévessin). Over 1000 people, from CERN and other International Organizations, came to enjoy the warm summer night, and to watch the best of the World's High Energy music. Jazz, rock, pop, country, metal, blues, funk and punk blasted out from 9 bands from the CERN Musiclub and Jazz club, alternating on two stages in a non-stop show.  The night reached its hottest point when The Canettes Blues Band got everybody dancing to sixties R&B tunes (pictured). Meanwhile, the bars and food vans were working at full capacity, under the expert management of the CERN Softball club, who were at the same time running a Softball tournament in the adjacent "Higgs Field". The Hardronic Festival is the main yearly CERN music event, and it is organized with the support of the Staff Association and the CERN Administration.

Study of infrared emission spectroscopy for the B1Δg–A1Πu and B′1Σg+–A1Πu systems of C2

International Nuclear Information System (INIS)

Chen, Wang; Kawaguchi, Kentarou; Tang, Jian; Bernath, Peter F.

2016-01-01

Thirteen bands for the B 1 Δ g –A 1 Π u system and eleven bands for the B ′1 Σ g + –A 1 Π u system of C 2 were identified in the Fourier transform infrared emission spectra of hydrocarbon discharges. The B ′1 Σ g + v = 4 and the B 1 Δ g v = 6, 7, and 8 vibrational levels involved in nine bands were studied for the first time. A direct global analysis with Dunham parameters was carried out satisfactorily for the B 1 Δ g –A 1 Π u system except for a small perturbation in the B 1 Δ g v = 6 level. The calculated rovibrational term energies up to B 1 Δ g v = 12 showed that the level crossing between the B 1 Δ g and d 3 Π g states is responsible for many of the prominent perturbations in the Swan system observed previously. Nineteen forbidden transitions of the B 1 Δ g –a 3 Π u transition were identified and the off-diagonal spin-orbit interaction constant A dB between d 3 Π g and B 1 Δ g was derived as 8.3(1) cm −1 . For the B ′1 Σ g + –A 1 Π u system, only individual band analyses for each vibrational level in the B′ 1 Σ g + state could be done satisfactorily and Dunham parameters obtained from these effective parameters showed that the anharmonic vibrational constant ω e x e is anomalously small (nearly zero). Inspection of the RKR (Rydberg-Klein-Rees) potential curves for the B ′1 Σ g + and X 1 Σ g + states revealed that an avoided crossing or nearly avoided crossing may occur around 30 000 cm −1 , which is responsible for the anomalous molecular constants in these two states

Band gap engineering of BC2N for nanoelectronic applications

Science.gov (United States)

Lim, Wei Hong; Hamzah, Afiq; Ahmadi, Mohammad Taghi; Ismail, Razali

2017-12-01

The BC2N as an example of boron-carbon-nitride (BCN), has the analogous structure as the graphene and boron nitride. It is predicted to have controllable electronic properties. Therefore, the analytical study on the engineer-able band gap of the BC2N is carried out based on the schematic structure of BC2N. The Nearest Neighbour Tight Binding (NNTB) model is employed with the dispersion relation and the density of state (DOS) as the main band gap analysing parameter. The results show that the hopping integrals having the significant effect on the band gap, band structure and DOS of BC2N nanowire (BC2NNW) need to be taken into consideration. The presented model indicates consistent trends with the published computational results around the Dirac points with the extracted band gap of 0.12 eV. Also, it is distinguished that wide energy gap of boron nitride (BN) is successfully narrowed by this carbon doped material which assures the application of BC2N on the nanoelectronics and optoelectronics in the near future.

A Compact Printed Quadruple Band-Notched UWB Antenna

Directory of Open Access Journals (Sweden)

Xiaoyin Li

2013-01-01

Full Text Available A novel compact coplanar waveguide- (CPW- fed ultrawideband (UWB printed planar volcano-smoke antenna (PVSA with four band-notches for various wireless applications is proposed and demonstrated. The low-profile antenna consists of a C-shaped parasitic strip to generate a notched band at 8.01~8.55 GHz for the ITU band, two C-shaped slots, and an inverted U-shaped slot etched in the radiator patch to create three notched bands at 5.15~5.35 GHz, 5.75~5.85 GHz, and 7.25~7.75 GHz for filtering the WLAN and X-band satellite signals. Simulated and measured results both confirm that the proposed antenna has a broad bandwidth of 3.1~12 GHz with VSWR < 2 and good omnidirectional radiation patterns with four notched-bands.

Divergent plate motion drives rapid exhumation of (ultra)high pressure rocks

Science.gov (United States)

Liao, Jie; Malusà, Marco G.; Zhao, Liang; Baldwin, Suzanne L.; Fitzgerald, Paul G.; Gerya, Taras

2018-06-01

Exhumation of (ultra)high pressure [(U)HP] rocks by upper-plate divergent motion above an unbroken slab, first proposed in the Western Alps, has never been tested by numerical methods. We present 2D thermo-mechanical models incorporating subduction of a thinned continental margin beneath either a continental or oceanic upper plate, followed by upper-plate divergent motion away from the lower plate. Results demonstrate how divergent plate motion may trigger rapid exhumation of large volumes of (U)HP rocks directly to the Earth's surface, without the need for significant overburden removal by erosion. Model exhumation paths are fully consistent with natural examples for a wide range of upper-plate divergence rates. Exhumation rates are systematically higher than the divergent rate imposed to the upper plate, and the modeled size of exhumed (U)HP domes is invariant for different rates of upper-plate divergence. Major variations are instead predicted at depth for differing model scenarios, as larger amounts of divergent motion may allow mantle-wedge exhumation to shallow depth under the exhuming domes. The transient temperature increase, due to ascent of mantle-wedge material in the subduction channel, has a limited effect on exhumed continental (U)HP rocks already at the surface. We test two examples, the Cenozoic (U)HP terranes of the Western Alps (continental upper plate) and eastern Papua New Guinea (oceanic upper plate). The good fit between model predictions and the geologic record in these terranes encourages the application of these models globally to pre-Cenozoic (U)HP terranes where the geologic record of exhumation is only partly preserved.

Simulation of CO2–water–rock interactions on geologic CO2 sequestration under geological conditions of China

International Nuclear Information System (INIS)

Wang, Tianye; Wang, Huaiyuan; Zhang, Fengjun; Xu, Tianfu

2013-01-01

Highlights: • We determined the feasibilities of geologic CO 2 sequestration in China. • We determined the formation of gibbsite suggested CO 2 can be captured by rocks. • We suggested the mechanisms of CO 2 –water–rock interactions. • We found the corrosion and dissolution of the rock increased as temperature rose. -- Abstract: The main purpose of this study focused on the feasibility of geologic CO 2 sequestration within the actual geological conditions of the first Carbon Capture and Storage (CCS) project in China. This study investigated CO 2 –water–rock interactions under simulated hydrothermal conditions via physicochemical analyses and scanning electron microscopy (SEM). Mass loss measurement and SEM showed that corrosion of feldspars, silica, and clay minerals increased with increasing temperature. Corrosion of sandstone samples in the CO 2 -containing fluid showed a positive correlation with temperature. During reaction at 70 °C, 85 °C, and 100 °C, gibbsite (an intermediate mineral product) formed on the sample surface. This demonstrated mineral capture of CO 2 and supported the feasibility of geologic CO 2 sequestration. Chemical analyses suggested a dissolution–reprecipitation mechanism underlying the CO 2 –water–rock interactions. The results of this study suggested that mineral dissolution, new mineral precipitation, and carbonic acid formation-dissociation are closely interrelated in CO 2 –water–rock interactions

Fourier spectroscopy of the 12C2, 13C2, and 12C13C (0-0) swan bands

International Nuclear Information System (INIS)

Amiot, C.

1983-01-01

The (0-0) band of the C 2 Swan electronic system d 3 Pi/sub g/→a 3 Pi/sub u/ has been recorded by Fourier spectroscopy. The three isotopes species 12 C 2 , 13 C 2 , and 12 C 13 C were investigated. The observed wavenumbers were reduced to molecular parameters using a nonlinear least-square fitting procedure. Well-known perturbations at N' = 47 and N' = 51 again observed in the e 12 C 2 d 3 Pi/sub g/ (v = 0) level. Perturbations of the same kind are present in the 13 C 2 spectrum at N' = 34 and N' = 44,48,52. The 12 C 13 C spectrum exhibits in the observed spectral range a unique perturbation for N' = 41

Electron correlations in narrow band systems

International Nuclear Information System (INIS)

Kishore, R.

1983-01-01

The effect of the electron correlations in narrow bands, such as d(f) bands in the transition (rare earth) metals and their compounds and the impurity bands in doped semiconductors is studied. The narrow band systems is described, by the Hubbard Hamiltonian. By proposing a local self-energy for the interacting electron, it is found that the results are exact in both atomic and band limits and reduce to the Hartree Fock results for U/Δ → 0, where U is the intra-atomic Coulomb interaction and Δ is the bandwidth of the noninteracting electrons. For the Lorentzian form of the density of states of the noninteracting electrons, this approximation turns out to be equivalent to the third Hubbard approximation. A simple argument, based on the mean free path obtained from the imaginary part of the self energy, shows how the electron correlations can give rise to a discontinous metal-nonmetal transition as proposed by Mott. The band narrowing and the existence of the satellite below the Fermi energy in Ni, found in photoemission experiments, can also be understood. (Author) [pt

No Reprieve for Tasmanian Rock Art

Directory of Open Access Journals (Sweden)

Peter C. Sims

2013-10-01

Full Text Available The Australian State of Tasmania, at latitude 42 degrees south, became an island about 8,000 years ago when the sea rose to its present level, following the melting of polar and glacial ice that covered much of the land mass. After that time, the Tasmanian Aboriginal rock art developed independently of mainland Australia, with its form being basically linear with some naturalistic figures and a predominance of cupules. The petroglyphs with one lithophone site occur on various rock substrates varying in hardness from granite to sandstone. Many sites exist along the western coastline that borders the Southern Ocean where the landscape in some places has changed little since the arrival of Europeans in 1803. The significance of this Tasmanian Aboriginal cultural heritage along what is now known as the Tarkine Coast, named after an Aboriginal band that once inhabited this area, was recognised by the Australian Government in February 2013 when a 21,000 ha strip, 2 km wide, was inscribed on its National Heritage Register, being one of 98 special places listed in the country. However, politics and racism hamper its management. This paper is based on the results of 40 years of field recording of the Tasmanian Aboriginal rock art sites, many of which remain unpublished.

Substoichiometric determination of uranium in phosphate rock

Energy Technology Data Exchange (ETDEWEB)

Suzuki, N; Hanzawa, K; Imura, H

1986-01-01

The substoichiometric isotope dilution analysis for U(VI) in a synergic extraction system of an excess amount of a chelating agent hexafluoroacetylacetone (HHFA) and a substoichiometric amount of U(VI) can be precisely extracted, and U down to ppm levels can be accurately determined by the present method. This method was applied to the analysis of a phosphate rock.

A reconnaissance Rb-Sr, Sm-Nd, U-Pb, and K-Ar study of some host rocks and ore minerals in the West Shasta Cu- Zn district, California ( USA).

Science.gov (United States)

Kistler, R.W.; McKee, E.H.; Futa, K.; Peterman, Z.E.; Zartman, R.E.

1985-01-01

The Copley Greenstone, Balaklala Rhyolite, and Mule Mountain stock in the West Shasta Cu-Zn district, California, have Rb-Sr, Sm-Nd, U-Pb, and K-Ar systematics that indicate they are a cogenetic suite of ensimatic island-arc rocks about 400 Ma. Pervasive alteration and mineralization of these rocks, for the most part, was syngenetic and the major component of the mineralizing fluid was Devonian seawater. K-Ar ages of quarz-sericite concentrates from ore horizons and Rb-Sr systematics of a few rock and ore specimens record a later thermal and mineralizing event in the district of about 260 Ma. Contamination of some rocks with pelagic sediments is indicated by the Sm-Nd data. -Authors

Rock mechanics. Proceedings of the 33rd U.S. symposium

International Nuclear Information System (INIS)

Tillerson, J.R.; Wawersik, W.R.

1992-01-01

After giving abstracts of the award winning papers for 1991 and the keynote lecture, papers are presented under the following headings: origin of stresses in the lithosphere; fault mechanics; rock mass monitoring; subsidence and ground motions; blasting; reservoir completion and stimulation; underground storage and sealing; design and supports; fluid and contaminant transport; numerical methods; constitutive modelling and strain localization; nonlinear dynamic systems; geostatistics and reliability; fracture mechanics; physical rock properties; experimental methods; geotechnical design methodology - workshop; and induced seismicity - workshop. Six papers have been abstracted separately

Investigation of Rock Failure Pattern in Creep by Digital Speckle Correlation Method

Directory of Open Access Journals (Sweden)

Yunliang Tan

2013-01-01

Full Text Available In order to study the mechanical characteristics from creep deformation to failure of rock, the tests of uniaxial compression and pushing steel-plate anchored in rock were performed, by using RLJW-2000 servo test synchronizing with Digital Speckle Correlation Method (DSCM. The investigations showed that for a uniaxial compressive specimen, when load arrived at 0.5σc, displacement clusters orderly formed, which was ahead of the macrocreep strain occurring in a slight jump mode when load arrived at 0.7σc. When the load level arrived at 0.8σc, displacement clusters gathered to be a narrow band. After that, the specimen abruptly fractured in a shear mode. In the creep pushing steel-plate test, when pushing force arrived at 25 kN, crack began to occur, the horizontal displacement field as well as shear strain field concentrated continuously along the interface between steel-plate and rock, and a new narrow concentrating band gathered in the upper layer. When pushing force arrived at 27.5 kN, another new narrow shear deformation band formed in the lower layer. Then, the steel-plate was pushed out quickly accompanying strong creep deformation.

Geochemistry of the rocks of the Strath Halladale-Altnabreac district

International Nuclear Information System (INIS)

Storey, B.C.; Lintern, B.C.

1981-09-01

The G 3 Strath Halladale Granite suite and associated aplites and granitic sheets crystallised from a mildly alkaline magma. This suite of acid igneous rocks shows a marked lack of iron enrichment, high levels of alkali elements and high Na 2 O/K 2 O ratios. The aplites, granitic sheets and rocks from boreholes A1A and A1C have higher SiO 2 contents and are more differentiated varieties of the suite. They have high levels of the incompatible elements K 2 O, Rb, U, Th and Y. Zr and the light rare earth elements behave as compatible elements and are depleted in the more evolved rocks. The basic and intermediate rocks, which most likely developed from a similar mildly alkaline magma, have high levels of the alkaline elements and are enriched in the light rare earth elements. The Ce/Y ratios are high and Zr/Nb ratios are low which are characteristic of the alkali nature of these rocks. The G 1 granite which shows some chemical variation to the G 3 suite has high levels of Th, Ti, Zr and Nb and similar large ion lithophile and rare earth element levels. The G 2 tonalites have lower SiO 2 contents, low K and Rb, and high Na, Sr and Y. This sodic phase may be related to the G 3 magma. (author)

76 FR 9224 - Drawbridge Operation Regulation; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2011-02-17

... issued a temporary deviation from the regulation governing the operation of the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois. The deviation.... SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island Arsenal requested a temporary deviation for the Rock Island...

Chromosome Banding in Amphibia. XXXII. The Genus Xenopus (Anura, Pipidae).

Science.gov (United States)

Schmid, Michael; Steinlein, Claus

2015-01-01

Mitotic chromosomes of 16 species of the frog genus Xenopus were prepared from kidney and lung cell cultures. In the chromosomes of 7 species, high-resolution replication banding patterns could be induced by treating the cultures with 5-bromodeoxyuridine (BrdU) and deoxythymidine (dT) in succession, and in 6 of these species the BrdU/dT-banded chromosomes could be arranged into karyotypes. In the 3 species of the clade with 2n = 20 and 4n = 40 chromosomes (X. tropicalis, X. epitropicalis, X. new tetraploid 1), as well as in the 3 species with 4n = 36 chromosomes (X. laevis, X. borealis, X. muelleri), the BrdU/dT-banded karyotypes show a high degree of homoeology, though differences were detected between these groups. Translocations, inversions, insertions or sex-specific replication bands were not observed. Minor replication asynchronies found between chromosomes probably involve heterochromatic regions. BrdU/dT replication banding of Xenopus chromosomes provides the landmarks necessary for the exact physical mapping of genes and repetitive sequences. FISH with an X. laevis 5S rDNA probe detected multiple hybridization sites at or near the long-arm telomeric regions in most chromosomes of X. laevis and X. borealis, whereas in X. muelleri, the 5S rDNA sequences are located exclusively at the long-arm telomeres of a single chromosome pair. Staining with the AT base pair-specific fluorochrome quinacrine mustard revealed brightly fluorescing heterochromatic regions in the majority of X. borealis chromosomes which are absent in other Xenopus species.

Zircon U-Pb geochronology and emplacement history of intrusive rocks in the Ardestan section, central Iran

Energy Technology Data Exchange (ETDEWEB)

Sarjoughian, F.; Kananian, A.

2017-11-01

The Urumieh-Dokhtar Magmatic Arc (UDMA) is part of the Alpine–Himalayan orogenic belt and interpreted to be a subduction-related Andean-type magmatic arc. Along this belt, Eocene volcanics and some gabbroic to granitic bodies crop out. The main rock types of the studied intrusion are granite, granodiorite, and diorite. They have geochemical features typical of magnesian, calc-alkaline, metaluminous to slightly peraluminous granites and I-type intrusive rock that have a strong enrichment in Large-Ion Lithophile (LIL) elements (e.g. Rb, Ba, Sr), and a depletion in High Field Strength (HFS) elements (e.g. Nb, Ti, P), typical of subduction-related magmas. Zircon U-Pb dating was applied to determine the emplacement ages of the different intrusions in the Ardestan area. Among them the Kuh-e Dom diorite is 53.9±0.4Ma old; the Kuh-e Dom granodiorite is 51.10±0.4Ma old; the Mehrabad granodiorite is 36.8±0.5Ma old, the Nasrand granodiorite is 36.5±0.5Ma old, the Zafarghand granodiorite is 24.6±1.0Ma old, and the Feshark granodiorite is 20.5±0.8Ma old. These results delineate more accurately the magmatic evolution related to the Neotethyan subduction from the Lower Eocene to Lower Miocene, and the subsequent Zagros orogeny that resulted from the Arabia-Eurasia collision. The emplacement of these intrusive rocks inside the UDMA, which has a close relationship with the collisional orogeny, is transitional from a subduction-related setting to post-collisional setting in the Ardestan area.

Zircon U-Pb geochronology and emplacement history of intrusive rocks in the Ardestan section, central Iran

International Nuclear Information System (INIS)

Sarjoughian, F.; Kananian, A.

2017-01-01

The Urumieh-Dokhtar Magmatic Arc (UDMA) is part of the Alpine–Himalayan orogenic belt and interpreted to be a subduction-related Andean-type magmatic arc. Along this belt, Eocene volcanics and some gabbroic to granitic bodies crop out. The main rock types of the studied intrusion are granite, granodiorite, and diorite. They have geochemical features typical of magnesian, calc-alkaline, metaluminous to slightly peraluminous granites and I-type intrusive rock that have a strong enrichment in Large-Ion Lithophile (LIL) elements (e.g. Rb, Ba, Sr), and a depletion in High Field Strength (HFS) elements (e.g. Nb, Ti, P), typical of subduction-related magmas. Zircon U-Pb dating was applied to determine the emplacement ages of the different intrusions in the Ardestan area. Among them the Kuh-e Dom diorite is 53.9±0.4Ma old; the Kuh-e Dom granodiorite is 51.10±0.4Ma old; the Mehrabad granodiorite is 36.8±0.5Ma old, the Nasrand granodiorite is 36.5±0.5Ma old, the Zafarghand granodiorite is 24.6±1.0Ma old, and the Feshark granodiorite is 20.5±0.8Ma old. These results delineate more accurately the magmatic evolution related to the Neotethyan subduction from the Lower Eocene to Lower Miocene, and the subsequent Zagros orogeny that resulted from the Arabia-Eurasia collision. The emplacement of these intrusive rocks inside the UDMA, which has a close relationship with the collisional orogeny, is transitional from a subduction-related setting to post-collisional setting in the Ardestan area.

Understanding the synergistic effects, optical and electronic properties of ternary Fe/C/S-doped TiO2 anatase within the DFT 1 U approach

CSIR Research Space (South Africa)

Opoku, F

2017-09-01

Full Text Available property of TiO2doped with Fe, C, and S are investigated in detail using the density functional theory + U method. The calculated band gap (3.21 eV) of TiO2anatase agree well with the experimental band gap (3.20 eV). The defect formation energy shows...

A Printed Monopole Antenna for Triple-Band WLAN/WiMAX Applications

Directory of Open Access Journals (Sweden)

Huiqing Zhai

2015-01-01

Full Text Available A new compact design of monopole antenna for triple-band WLAN/WiMAX applications with two band-notches based on broadband antenna is presented. By introducing a stub loaded ground and two new paper clip structures etched on radiation patch, a compact overall dimension 31 mm × 33 mm × 1 mm and three separated operating bands effectively covering 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands can be achieved. Compared with familiar U type slot, the introduced compact paper clip structure can save about 37% of dimension regions, which could effectively improve efficiency of band-notch formation. Simulated and measured results demonstrate that the proposed antenna has good dipole-like radiation characteristics with appreciable gain across the operating bands. Besides, main parameters of the two etched paper clip structures are investigated to control the positions and bandwidths of the two stop-bands, respectively, on basis of which the three working bands can be adjusted independently.

Dual band monopole antenna for WLAN 2.4/5.2/5.8 with truncated ground

Science.gov (United States)

Chandan, Bharti, Gagandeep; Srivastava, Toolika; Rai, B. S.

2018-04-01

A dual-band mono-pole antenna is proposed for Wireless LAN applications. The WLAN band is obtained by cutting a rectangular ring and a circular slot in the radiating patch. The overall dimension of antenna is 17×16.5×0.8 mmł. The frequency bands obtained are 2.38-2.9 GHz and 4.7-6.1 GHz with ≤ - 10 dB return loss which covers WLAN 2.4/5.2/5.8 GHz bands. The behavior of the antenna is analyzed in terms of radiation pattern, peak realized gain, radiation efficiency and surface current density. It has dipole like radiation pattern with gain of 2.33 - 4.31 dBi for lower frequency band and 4.29 - 5.16 dBi for upper frequency band with radiation efficiency of 95-98% and 93-96% respectively. The parametric analysis is carried out to understand the consequence of the various shape parameters and to get an optimum design. The simulation and measurement gave the results having close agreement.

Deformation bands in porous sandstones their microstructure and petrophysical properties

Energy Technology Data Exchange (ETDEWEB)

Torabi, Anita

2007-12-15

Deformation bands are commonly thin tabular zones of crushed or reorganized grains that form in highly porous rocks and sediments. Unlike a fault, typically the slip is negligible in deformation bands. In this dissertation the microstructure and petrophysical properties of deformation bands have been investigated through microscopy and numerical analysis of experimental and natural examples. The experimental work consists of a series of ring-shear experiments performed on porous sand at 5 and 20 MPa normal stresses and followed by microscopic examination of thin sections from the sheared samples. The results of the ring-shear experiments and comparison of them to natural deformation bands reveals that burial depth (level of normal stress in the experiments) and the amount of shear displacement during deformation are the two significant factors influencing the mode in which grains break and the type of shear zone that forms. Two end-member types of experimental shear zones were identified: (a) Shear zones with diffuse boundaries, which formed at low levels of normal stress and/or shear displacement; and (b) Shear zones with sharp boundaries, which formed at higher levels of normal stress and/or shear displacement. Our interpretation is that with increasing burial depth (approximately more than one kilometer, simulated in the experiments by higher levels of normal stress), the predominant mode of grain fracturing changes from flaking to splitting; which facilitates the formation of sharp-boundary shear zones. This change to grain splitting increases the power law dimension of the grain size distribution (D is about 1.5 in sharp boundary shear zones). Based on our observations, initial grain size has no influence in the deformation behavior of the sand at 5 MPa normal stresses. A new type of cataclastic deformation band is described through outcrop and microscopic studies; here termed a 'slipped deformation band'. Whereas previously reported cataclastic

Petrogenesis of cataclastic rocks within the San Andreas fault zone of Southern California U.S.A.

Science.gov (United States)

Lawford Anderson, J.; Osborne, Robert H.; Palmer, Donald F.

1980-08-01

This paper petrologically characterizes cataclastic rocks derived from four sites within the San Andreas fault zone of southern California. In this area, the fault traverses an extensive plutonic and metamorphic terrane and the principal cataclastic rock formed at these upper crustal levels is unindurated gouge derived from a range of crystalline rocks including diorite, tonalite, granite, aplite, and pegmatite. The mineralogical nature of this gouge is decidedly different from the "clay gouge" reported by Wu (1975) for central California and is essentially a rock flour with a quartz, feldspar, biotite, chlorite, amphibole, epidote and oxide mineralogy representing the milled-down equivalent of the original rock. Clay development is minor (less than 4 wt. %) to nonexistent and is exclusively kaolinite. Alterations involve hematitic oxidation, chlorite alteration on biotite and amphibole, and local introduction of calcite. Electron microprobe analysis showed that in general the major minerals were not reequilibrated with the pressure—temperature regime imposed during cataclasis. Petrochemically, the form of cataclasis that we have investigated is largely an isochemical process. Some hydration occurs but the maximum amount is less than 2.2% added H 2O. Study of a 375 m deep core from a tonalite pluton adjacent to the fault showed that for Si, Al, Ti, Fe, Mg, Mn, K, Na, Li, Rb, and Ba, no leaching and/or enrichment occurred. Several samples experienced a depletion in Sr during cataclasis while lesser number had an enrichment of Ca (result of calcite veining). Texturally, the fault gouge is not dominated by clay-size material but consists largely of silt and fine sand-sized particles. An intriguing aspect of our work on the drill core is a general decrease in particulate size with depth (and confining pressure) with the predominate shifting sequentially from fine sand to silt-size material. The original fabric of these rocks is commonly not disrupted during the

Dilatant shear band formation and diagenesis in calcareous, arkosic sandstones, Vienna Basin (Austria)

Science.gov (United States)

Lommatzsch, Marco; Exner, Ulrike; Gier, Susanne; Grasemann, Bernhard

2015-01-01

The present study examines deformation bands in calcareous arkosic sands. The investigated units can be considered as an equivalent to the Matzen field in the Vienna Basin (Austria), which is one of the most productive oil reservoirs in central Europe. The outcrop exposes carbonate-free and carbonatic sediments of Badenian age separated by a normal fault. Carbonatic sediments in the hanging wall of the normal fault develop dilation bands with minor shear displacements (< 2 mm), whereas carbonate-free sediments in the footwall develop cataclastic shear bands with up to 70 cm displacement. The cataclastic shear bands show a permeability reduction up to 3 orders of magnitude and strong baffling effects in the vadose zone. Carbonatic dilation bands show a permeability reduction of 1-2 orders of magnitude and no baffling structures. We distinguished two types of deformation bands in the carbonatic units, which differ in deformation mechanisms, distribution and composition. Full-cemented bands form as dilation bands with an intense syn-kinematic calcite cementation, whereas the younger loose-cemented bands are dilatant shear bands cemented by patchy calcite and clay minerals. All analyzed bands are characterized by a porosity and permeability reduction caused by grain fracturing and cementation. The changed petrophysical properties and especially the porosity evolution are closely related to diagenetic processes driven by varying pore fluids in different diagenetic environments. The deformation band evolution and sealing capacity is controlled by the initial host rock composition. PMID:26300577

Nu2U

DEFF Research Database (Denmark)

Sørensen, Hans Eibe; Williamson, Trevor

Abstract In September 2014, nine months after launching a major growth opportunity, Jenny Dunne, managing director of Nu2U, called for an extraordinary status meeting with her COO and CMO. A fast-growing online retailer of refurbished household appliances, Nu2U planned to acquire market share...... by improving internal logistics and delivery services, aided by a new, fully integrated software system. The company's gross profit had been increasing steadily, but recent accounts revealed a fall in net profit margins. It became apparent that implementation of the business plan for the project...... was problematic because of loose governance and poor communication across Nu2U's different specialist functions during planning and implementation. The Nu2U case illustrates how executives' cognition and span of control/overview may be hampered in fast-growing firms and how this ...

Mineral storage of CO2/H2S gas mixture injection in basaltic rocks

Science.gov (United States)

Clark, D. E.; Gunnarsson, I.; Aradottir, E. S.; Oelkers, E. H.; Sigfússon, B.; Snæbjörnsdottír, S. Ó.; Matter, J. M.; Stute, M.; Júlíusson, B. M.; Gíslason, S. R.

2017-12-01

Carbon capture and storage is one solution to reducing CO2 emissions in the atmosphere. The long-term geological storage of buoyant supercritical CO2 requires high integrity cap rock. Some of the risk associated with CO2 buoyancy can be overcome by dissolving CO2 into water during its injection, thus eliminating its buoyancy. This enables injection into fractured rocks, such as basaltic rocks along oceanic ridges and on continents. Basaltic rocks are rich in divalent cations, Ca2+, Mg2+ and Fe2+, which react with CO2 dissolved in water to form stable carbonate minerals. This possibility has been successfully tested as a part of the CarbFix CO2storage pilot project at the Hellisheiði geothermal power plant in Iceland, where they have shown mineralization occurs in less than two years [1, 2]. Reykjavik Energy and the CarbFix group has been injecting a mixture of CO2 and H2S at 750 m depth and 240-250°C since June 2014; by 1 January 2016, 6290 tons of CO2 and 3530 tons of H2S had been injected. Once in the geothermal reservoir, the heat exchange and sufficient dissolution of the host rock neutralizes the gas-charged water and saturates the formation water respecting carbonate and sulfur minerals. A thermally stable inert tracer was also mixed into the stream to monitor the subsurface transport and to assess the degree of subsurface carbonation and sulfide precipitation [3]. Water and gas samples have been continuously collected from three monitoring wells and geochemically analyzed. Based on the results, mineral saturation stages have been defined. These results and tracer mass balance calculations are used to evaluate the rate and magnitude of CO2 and H2S mineralization in the subsurface, with indications that mineralization of carbon and sulfur occurs within months. [1] Gunnsarsson, I., et al. (2017). Rapid and cost-effective capture and subsurface mineral storage of carbon and sulfur. Manuscript submitted for publication. [2] Matter, J., et al. (2016). Rapid

The uranium behaviour during rock-water interaction in the granites from the Itu complex (Sao Paulo, Brazil): a laboratory study

Energy Technology Data Exchange (ETDEWEB)

Silva, Helen S.B. da; Marques, Leila S.; Kawauchi, Roberto K., E-mail: leila@iag.usp.br, E-mail: keiji@iag.usp.br [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas. Universidade de Sao Paulo (USP), SP (Brazil)

2011-07-01

In order to elucidate the mechanisms involved in the process of uranium leaching due to the rock-water interaction in the granitic rocks from Itu Complex (Sao Paulo, Brazil), an experimental arrangement was developed and built. About 2.5kg of crushed rock fragments from Cabreuva and Indaiatuba Intrusions were maintained at room temperature within a glass flask filled with circulating water. The percolating water was removed periodically (from 10 to 30 days) for uranium analysis and then replaced by an equal volume of fresh water. Alpha spectrometry was used to determine the activity concentrations of {sup 234}U and {sup 238}U, and {sup 234}U/{sup 238}U activity ratios, of the waters as well as of the granites. The results for both samples showed that most of the uranium is leached in the first days after the contact between rock and water. The {sup 234}U/{sup 238}U activity ratios were significantly greater than unity, indicating radioactive disequilibrium between those isotopes, probably due to alpha recoil. Although the uranium activity concentrations in the water samples diminished with the increasing of time, it was not observed considerable variations of the {sup 234}U/{sup 238}U activity ratios. It was also noticed that, the amount of leached uranium as well as the {sup 234}U/{sup 238}U activity ratios are characteristics of each sample submitted to leaching, reflecting the differences of the granite facies mineralogy.(author)

Study on flow and mass transport through fractured sedimentary rocks (2)

International Nuclear Information System (INIS)

Shimo, Michito; Kumamoto, Sou; Karasaki, Kenzi; Sato, Hisashi; Sawada, Atsushi

2009-03-01

It is important for safety assessment of HLW geological disposal to understand hydro-geological conditions at the investigation area, and to evaluate groundwater flow and mass transport model and parameters, at each investigation phase. Traditionally, for Neogene sedimentary rock, the grain spacing of sediments has been considered as the dominant migration path. However, fractures of sedimentary rock could act as dominant paths, although they were soft sedimentary rocks. In this study, as part of developing groundwater flow and mass transport evaluation methodologies of such a fractured sedimentary rock' distributed area, we conducted two different scale of studies; 1) core rock sample scale and 2) several kilometer scale. For the core rock sample scale, some of laboratory hydraulic and tracer experiments have conducted using the rock cores with tailored parallel fracture, obtained at pilot borehole drilled in the vicinity of ventilation shaft. From the test results, hydraulic conductivity, diffusion coefficient, transport aperture, dispersion length and etc. was evaluated. Based on these test results, the influence of these parameters onto mass transport behavior of fractures sedimentary rocks was examined. For larger scale, such as several kilometer scale, the regional scale groundwater flow was examined using temperature data observed along the boreholes at Horonobe site. The results show that the low permeable zone between the boreholes might be estimated. (author)

Ground-state and pairing-vibrational bands with equal quadrupole collectivity in 124Xe

Science.gov (United States)

Radich, A. J.; Garrett, P. E.; Allmond, J. M.; Andreoiu, C.; Ball, G. C.; Bianco, L.; Bildstein, V.; Chagnon-Lessard, S.; Cross, D. S.; Demand, G. A.; Diaz Varela, A.; Dunlop, R.; Finlay, P.; Garnsworthy, A. B.; Hackman, G.; Hadinia, B.; Jigmeddorj, B.; Laffoley, A. T.; Leach, K. G.; Michetti-Wilson, J.; Orce, J. N.; Rajabali, M. M.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Wang, Z. M.; Wood, J. L.; Wong, J.; Williams, S. J.; Yates, S. W.

2015-04-01

The nuclear structure of 124Xe has been investigated via measurements of the β+/EC decay of 124Cs with the 8 π γ -ray spectrometer at the TRIUMF-ISAC facility. The data collected have enabled branching ratio measurements of weak, low-energy transitions from highly excited states, and the 2+→0+ in-band transitions have been observed. Combining these results with those from a previous Coulomb excitation study, B (E 2 ;23+→02+) =78 (13 ) W.u. and B (E 2 ;24+→03+) =53 (12 ) W.u. were determined. The 03+ state, in particular, is interpreted as the main fragment of the proton-pairing vibrational band identified in a previous 122Te (3He,n )124Xe measurement, and has quadrupole collectivity equal to, within uncertainty, that of the ground-state band.

Path integral for coherent states of the dynamical U2 group and U2/1 supergroup

International Nuclear Information System (INIS)

Kochetov, E.A.

1992-01-01

A part-integral formulation in the representation of coherent states for the unitary U 2 group and U 2/1 supergroup is introduced. U 2 and U 2/1 path integrals are shown to be defined on the coset spaces U 2 /U 1 xU 1 and U 2/1 /U 1/1 xU 1 , respectively. These coset appears as curved classical phase spaces. Partition functions are expressed as path integrals over these spaces. In the case when U 2 and U 2/1 are the dynamical groups, the corresponding path integrals are evaluated with the help of linear fractional transformations that appear as the group (supergroup) action in the coset space (superspace). Possible applications for quantum models are discussed. 9 refs

Band structural properties of MoS2 (molybdenite)

International Nuclear Information System (INIS)

Gupta, V.P.

1980-01-01

Semiconductivity and superconductivity in MoS 2 (molybdenite) can be understood in terms of the band structure of MoS 2 . The band structural properties of MoS 2 are presented here. The energy dependence of nsub(eff) and epsilon(infinity)sub(eff) is investigated. Using calculated values of nsub(eff) and epsilon(infinity)sub(eff), the Penn gap has been determined. The value thus obtained is shown to be in good agreement with the reflectivity data and also with the value obtained from the band structure. The Ravindra and Srivastava formula has been shown to give values for the isobaric temperature gradient of Esub(G)[(deltaEsub(G)/deltaT)sub(P)], which are in agreement with the experimental data, and the contribution to (deltaEsub(G)/deltaT)sub(P) due to the electron lattice interaction has been evaluated. In addition, the electronic polarizability has been calculated using a modified Lorentz-Lorenz relation. (author)

Respirable dust measured downwind during rock dust application.

Science.gov (United States)

Harris, M L; Organiscak, J; Klima, S; Perera, I E

2017-05-01

The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

Geotechnical aspects of rock borrow for large breakwaters

International Nuclear Information System (INIS)

Watson, I.; Fischer, J.A.; Urlich, C.M.

1975-01-01

The state of the art is described of investigations to secure rock borrow for the breakwaters proposed to protect offshore nuclear power plants. Considerations relating to the geological, geotechnical, and design suitability of rock are discussed within the framework of economics, and the environmental impact of quarrying and transporting rock to potential sites on the East and Gulf coasts of the U.S. is examined. The methodology outlined has application to the construction of all large rockfill breakwaters

Qualitative and quantitative changes in detrital reservoir rocks caused by CO2-brine-rock interactions during first injection phases (Utrillas sandstones, northern Spain)

Science.gov (United States)

Berrezueta, E.; Ordóñez-Casado, B.; Quintana, L.

2016-01-01

The aim of this article is to describe and interpret qualitative and quantitative changes at rock matrix scale of lower-upper Cretaceous sandstones exposed to supercritical (SC) CO2 and brine. The effects of experimental injection of CO2-rich brine during the first injection phases were studied at rock matrix scale, in a potential deep sedimentary reservoir in northern Spain (Utrillas unit, at the base of the Cenozoic Duero Basin).Experimental CO2-rich brine was exposed to sandstone in a reactor chamber under realistic conditions of deep saline formations (P ≈ 7.8 MPa, T ≈ 38 °C and 24 h exposure time). After the experiment, exposed and non-exposed equivalent sample sets were compared with the aim of assessing possible changes due to the effect of the CO2-rich brine exposure. Optical microscopy (OpM) and scanning electron microscopy (SEM) aided by optical image analysis (OIA) were used to compare the rock samples and get qualitative and quantitative information about mineralogy, texture and pore network distribution. Complementary chemical analyses were performed to refine the mineralogical information and to obtain whole rock geochemical data. Brine composition was also analyzed before and after the experiment.The petrographic study of contiguous sandstone samples (more external area of sample blocks) before and after CO2-rich brine injection indicates an evolution of the pore network (porosity increase ≈ 2 %). It is probable that these measured pore changes could be due to intergranular quartz matrix detachment and partial removal from the rock sample, considering them as the early features produced by the CO2-rich brine. Nevertheless, the whole rock and brine chemical analyses after interaction with CO2-rich brine do not present important changes in the mineralogical and chemical configuration of the rock with respect to initial conditions, ruling out relevant precipitation or dissolution at these early stages to rock-block scale. These results

Gamma Spectrometric Determination of U, Th, K and Some Geochemical Applications

International Nuclear Information System (INIS)

Dodona, A.; Tashko, A.

2001-01-01

The application of 'in situ' gamma-spectrometric method (''infinite'' environment), made possible the simultanious determination of U, Th and K. 4 channel gamma-spectrometric analyser with NaI(TI) scintilation counter crystal detector (103 cm 3 φ=50x50mm) was used to determin U, Th(more than 1-2 ppm) and K (more than 1%) in laboratory conditions. The detector was inserted into a lead camera and calibrated for measurement geometry with vessel of ''Marineli'' type of a 17o cm 3 volume. The study of main factors, which influence in the gamma spectrometric measurements, (the technical, physical, geometrical and time parameters) has been carried out. International standards of U, Th, K and internal monitoring standard samples are used for the calibration. External analytical control has been realized by other radiometric and chemical methods. The detection limits ( 1 ppm Th, 2ppm U and 1% K) and the relative errors (17-20% for 1-10 ppm U, Th and 10-15% for more than 10 ppm U, Th and more than 1% K) guarantee a quantitative analysis that may be used successfully in the geochemical studies. Some geochemical applications, based on the content of Th, U and Th/U ratio in rocks samples that we have we have analyzed with this method, are shown in this paper. U, Th and their ratio are used as trace elements to indicate the differences between the acidic magmatic rocks of Albania (Th/U ratio=2-6 and>10). The bimodal character of Th/U scattering in ignimbrides and monzonites (Korabi zone) shows that in addition to the ''normal'' rocks, there are also some ones enriched with Th, So, the differential analysis of Th, U, and K may be used as geochemical exploration criteria for the radioactive and non-radioactive mineralization, such as REE (Rare Earth Elements), phospghorites, bauxites, placers etc. (authors)

Doped Sc2C(OH)2 MXene: new type s-pd band inversion topological insulator.

Science.gov (United States)

Balcı, Erdem; Akkuş, Ünal Özden; Berber, Savas

2018-04-18

The electronic structures of Si and Ge substitutionally doped Sc 2 C(OH) 2 MXene monolayers are investigated in density functional theory. The doped systems exhibit band inversion, and are found to be topological invariants in Z 2 theory. The inclusion of spin orbit coupling results in band gap openings. Our results point out that the Si and Ge doped Sc 2 C(OH) 2 MXene monolayers are topological insulators. The band inversion is observed to have a new mechanism that involves s and pd states.

Doped Sc2C(OH)2 MXene: new type s-pd band inversion topological insulator

Science.gov (United States)

Balcı, Erdem; Özden Akkuş, Ünal; Berber, Savas

2018-04-01

The electronic structures of Si and Ge substitutionally doped Sc2C(OH)2 MXene monolayers are investigated in density functional theory. The doped systems exhibit band inversion, and are found to be topological invariants in Z 2 theory. The inclusion of spin orbit coupling results in band gap openings. Our results point out that the Si and Ge doped Sc2C(OH)2 MXene monolayers are topological insulators. The band inversion is observed to have a new mechanism that involves s and pd states.

Substrate Stiffness Influences Doxorubicin-Induced p53 Activation via ROCK2 Expression

Directory of Open Access Journals (Sweden)

Takahiro Ebata

2017-01-01

Full Text Available The physical properties of the extracellular matrix (ECM, such as stiffness, are involved in the determination of the characteristics of cancer cells, including chemotherapy sensitivity. Resistance to chemotherapy is often linked to dysfunction of tumor suppressor p53; however, it remains elusive whether the ECM microenvironment interferes with p53 activation in cancer cells. Here, we show that, in MCF-7 breast cancer cells, extracellular stiffness influences p53 activation induced by the antitumor drug doxorubicin. Cell growth inhibition by doxorubicin was increased in response to ECM rigidity in a p53-dependent manner. The expression of Rho-associated coiled coil-containing protein kinase (ROCK 2, which induces the activation of myosin II, was significantly higher when cells were cultured on stiffer ECM substrates. Knockdown of ROCK2 expression or pharmacological inhibition of ROCK decreased doxorubicin-induced p53 activation. Our results suggest that a soft ECM causes downregulation of ROCK2 expression, which drives resistance to chemotherapy by repressing p53 activation.

U-isotopes and "2"2"6Ra as tracers of hydrogeochemical processes in carbonated karst aquifers from arid areas

International Nuclear Information System (INIS)

Guerrero, José Luis; Vallejos, Ángela; Cerón, Juan Carlos; Sánchez-Martos, Francisco; Pulido-Bosch, Antonio; Bolívar, Juan Pedro

2016-01-01

Sierra de Gádor is a karst macrosystem with a highly complex geometry, located in southeastern Spain. In this arid environment, the main economic activities, agriculture and tourism, are supported by water resources from the Sierra de Gádor aquifer system. The aim of this work was to study the levels and behaviour of some of the most significant natural radionuclides in order to improve the knowledge of the hydrogeochemical processes involved in this groundwater system. For this study, 28 groundwater and 7 surface water samples were collected, and the activity concentrations of the natural U-isotopes ("2"3"8U, "2"3"5U and "2"3"4U) and "2"2"6Ra by alpha spectrometry were determined. The activity concentration of "2"3"8U presented a large variation from around 1.1 to 65 mBq L"−"1. Elevated groundwater U concentrations were the result of oxidising conditions that likely promoted U dissolution. The PHREEQC modelling code showed that dissolved U mainly existed as uranyl carbonate complexes. The "2"3"4U/"2"3"8U activity ratios were higher than unity for all samples (1.1–3.8). Additionally, these ratios were in greater disequilibrium in groundwater than surface water samples, the likely result of greater water-rock contact time. "2"2"6Ra presented a wide range of activity concentrations, (0.8 up to about 4 × 10"2 mBq L"−"1); greatest concentrations were detected in the thermal area of Alhama. Most of the samples showed "2"2"6Ra/"2"3"4U activity ratios lower than unity (median = 0.3), likely the result of the greater mobility of U than Ra in the aquifer system. The natural U-isotopes concentrations were strongly correlated with dissolution of sulphate evaporites (mainly gypsum). "2"2"6Ra had a more complex behaviour, showing a strong correlation with water salinity, which was particularly evident in locations where thermal anomalies were detected. The most saline samples showed the lowest "2"3"4U/"2"3"8U activity ratios, probably due to fast uniform bulk

Triple-Notched Band CPW fed UWB Antenna with Metallic Reflector for High Gain Performance

Directory of Open Access Journals (Sweden)

K. G. Jangid

2017-10-01

Full Text Available This paper exhibits the design and performance of a coplanar waveguide (CPW fed triple notched band ultra-wide band (UWB antenna. Proposed prototype has two U-shaped slots on the patch and an inverted U slot in feed line with a metal reflector beneath the radiating element. Proposed structure renders wider impedance bandwidth extended between frequencies 2.71GHz to 12.92 GHz for VSWR 2. The utmost simulated gain of proposed antenna with reflector is close to 9.9dBi at 7.4GHz. A sharp reduction observed in the efficiency values of the proposed structure at stop bands. Perhaps, this structure proved as a useful tool for various applications in modern communication systems including UWB.

The effects of buoyancy on shear-induced melt bands in a compacting porous medium

Science.gov (United States)

Butler, S. L.

2009-03-01

It has recently been shown [Holtzman, B., Groebner, N., Zimmerman, M., Ginsberg, S., Kohlstedt, D., 2003. Stress-driven melt segregation in partially molten rocks. Geochem. Geophys. Geosyst. 4, Art. No. 8607; Holtzman, B.K., Kohlstedt, D.L., 2007. Stress-driven melt segregation and strain partitioning in partially molten rocks: effects of stress and strain. J. Petrol. 48, 2379-2406] that when partially molten rock is subjected to simple shear, bands of high and low porosity are formed at a particular angle to the direction of instantaneous maximum extension. These have been modeled numerically and it has been speculated that high porosity bands may form an interconnected network with a bulk, effective permeability that is enhanced in a direction parallel to the bands. As a result, the bands may act to focus mantle melt towards the axis of mid-ocean ridges [Katz, R.F., Spiegelman, M., Holtzman, B., 2006. The dynamics of melt and shear localization in partially molten aggregates. Nature 442, 676-679]. In this contribution, we examine the combined effects of buoyancy and matrix shear on a deforming porous layer. The linear theory of Spiegelman [Spiegelman, M., 1993. Flow in deformable porous media. Part 1. Simple analysis. J. Fluid Mech. 247, 17-38; Spiegelman, M., 2003. Linear analysis of melt band formation by simple shear. Geochem. Geophys. Geosyst. 4, doi:10.1029/2002GC000499, Article 8615] and Katz et al. [Katz, R.F., Spiegelman, M., Holtzman, B., 2006. The dynamics of melt and shear localization in partially molten aggregates. Nature 442, 676-679] is generalized to include both the effects of buoyancy and matrix shear on a deformable porous layer with strain-rate dependent rheology. The predictions of linear theory are compared with the early time evolution of our 2D numerical model and they are found to be in excellent agreement. For conditions similar to the upper mantle, buoyancy forces can be similar to or much greater than matrix shear-induced forces. The

Grain size dependent optical band gap of CdI2 films

Indian Academy of Sciences (India)

Unknown

absorption data near band edge can be fitted to an indirect band gap of 3 eV. The dependence of band gap ... while to carry out the optical studies on CdI2 films in order to .... replotted as (αhν)1/2 vs hν to determine indirect gap as shown in the ...

Band offsets in ITO/Ga2O3 heterostructures

Science.gov (United States)

Carey, Patrick H.; Ren, F.; Hays, David C.; Gila, B. P.; Pearton, S. J.; Jang, Soohwan; Kuramata, Akito

2017-11-01

The valence band offsets in rf-sputtered Indium Tin Oxide (ITO)/single crystal β-Ga2O3 (ITO/Ga2O3) heterostructures were measured with X-Ray Photoelectron Spectroscopy using the Kraut method. The bandgaps of the component materials in the heterostructure were determined by Reflection Electron Energy Loss Spectroscopy as 4.6 eV for Ga2O3 and 3.5 eV for ITO. The valence band offset was determined to be -0.78 ± 0.30 eV, while the conduction band offset was determined to be -0.32 ± 0.13 eV. The ITO/Ga2O3 system has a nested gap (type I) alignment. The use of a thin layer of ITO between a metal and the Ga2O3 is an attractive approach for reducing contact resistance on Ga2O3-based power electronic devices and solar-blind photodetectors.

Optical model with multiple band couplings using soft rotator structure

Science.gov (United States)

Martyanov, Dmitry; Soukhovitskii, Efrem; Capote, Roberto; Quesada, Jose Manuel; Chiba, Satoshi

2017-09-01

A new dispersive coupled-channel optical model (DCCOM) is derived that describes nucleon scattering on 238U and 232Th targets using a soft-rotator-model (SRM) description of the collective levels of the target nucleus. SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate coupling matrix elements of the generalized optical model. Five rotational bands are coupled: the ground-state band, β-, γ-, non-axial- bands, and a negative parity band. Such coupling scheme includes almost all levels below 1.2 MeV of excitation energy of targets. The "effective" deformations that define inter-band couplings are derived from SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a monopolar deformed potential leading to additional couplings between rotational bands. The present DCCOM describes the total cross section differences between 238U and 232Th targets within experimental uncertainty from 50 keV up to 200 MeV of neutron incident energy. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus (CN) formation cross sections, which is significantly different from the one calculated with rigid-rotor potentials with any number of coupled levels.

Determination of band alignment in the single-layer MoS2/WSe2 heterojunction

KAUST Repository

Chiu, Ming-Hui; Zhang, Chendong; Shiu, Hung-Wei; Chuu, Chih-Piao; Chen, Chang-Hsiao; Chang, Chih-Yuan S.; Chen, Chia-Hao; Chou, Mei-Yin; Shih, Chih-Kang; Li, Lain-Jong

2015-01-01

The emergence of two-dimensional electronic materials has stimulated proposals of novel electronic and photonic devices based on the heterostructures of transition metal dichalcogenides. Here we report the determination of band offsets in the heterostructures of transition metal dichalcogenides by using microbeam X-ray photoelectron spectroscopy and scanning tunnelling microscopy/spectroscopy. We determine a type-II alignment between MoS2 and WSe2 with a valence band offset value of 0.83 eV and a conduction band offset of 0.76 eV. First-principles calculations show that in this heterostructure with dissimilar chalcogen atoms, the electronic structures of WSe2 and MoS2 are well retained in their respective layers due to a weak interlayer coupling. Moreover, a valence band offset of 0.94 eV is obtained from density functional theory, consistent with the experimental determination.

Determination of band alignment in the single-layer MoS2/WSe2 heterojunction

KAUST Repository

Chiu, Ming-Hui

2015-07-16

The emergence of two-dimensional electronic materials has stimulated proposals of novel electronic and photonic devices based on the heterostructures of transition metal dichalcogenides. Here we report the determination of band offsets in the heterostructures of transition metal dichalcogenides by using microbeam X-ray photoelectron spectroscopy and scanning tunnelling microscopy/spectroscopy. We determine a type-II alignment between MoS2 and WSe2 with a valence band offset value of 0.83 eV and a conduction band offset of 0.76 eV. First-principles calculations show that in this heterostructure with dissimilar chalcogen atoms, the electronic structures of WSe2 and MoS2 are well retained in their respective layers due to a weak interlayer coupling. Moreover, a valence band offset of 0.94 eV is obtained from density functional theory, consistent with the experimental determination.

An evaluation of thematic mapper simulator data for the geobotanical discrimination of rock types in Southwest Oregon

Science.gov (United States)

Weinstock, K. J.; Morrissey, L. A.

1984-01-01

Rock type identification may be assisted by the use of remote sensing of associated vegetation, particularly in areas of dense vegetative cover where surface materials are not imaged directly by the sensor. The geobotanical discrimination of ultramafic parent materials was investigated and analytical techniques for lithologic mapping and mineral exploration were developed. The utility of remotely sensed data to discriminate vegetation types associated with ultramafic parent materials in a study area in southwest Oregon were evaluated. A number of specific objectives were identified, which include: (1) establishment of the association between vegetation and rock types; (2) examination of the spectral separability of vegetation types associated with rock types; (3) determination of the contribution of each TMS band for discriminating vegetation associated with rock types and (4) comparison of analytical techniques for spectrally classifying vegetation.

Sub-band-gap absorption in Ga2O3

Science.gov (United States)

Peelaers, Hartwin; Van de Walle, Chris G.

2017-10-01

β-Ga2O3 is a transparent conducting oxide that, due to its large bandgap of 4.8 eV, exhibits transparency into the UV. However, the free carriers that enable the conductivity can absorb light. We study the effect of free carriers on the properties of Ga2O3 using hybrid density functional theory. The presence of free carriers leads to sub-band-gap absorption and a Burstein-Moss shift in the onset of absorption. We find that for a concentration of 1020 carriers, the Fermi level is located 0.23 eV above the conduction-band minimum. This leads to an increase in the electron effective mass from 0.27-0.28 me to 0.35-0.37 me and a sub-band-gap absorption band with a peak value of 0.6 × 103 cm-1 at 3.37 eV for light polarized along the x or z direction. Both across-the-gap and free-carrier absorption depend strongly on the polarization of the incoming light. We also provide parametrizations of the conduction-band shape and the effective mass as a function of the Fermi level.

Experimental study of the 2p-2h band in 111Sn

International Nuclear Information System (INIS)

Ganguly, S.; Banerjee, P.; Ray, I.; Kshetri, R.; Raut, R.; Bhattacharya, S.; Saha-Sarkar, M.; Goswami, A.; Basu, S. K.

2008-01-01

The ΔI=2 intruder band in 111 Sn, built upon the 4074.3 keV state, was studied. The states were populated in the 100 Mo( 20 Ne, α5n) reaction at a beam energy of 136 MeV. Mean lifetimes of five states up to 8737.2 keV (spin 43/2 - ) have been measured for the first time using the Doppler shift attenuation method. In addition, an upper limit of mean lifetime has been estimated for the 9860.0 keV (spin 47/2 - ) state. The B(E2) values, derived from the present lifetime results, indicate a quadrupole deformation of β 2 =0.28±0.02 for the 31/2 - state and decrease progressively with spin, suggesting a reduction in collectivity. The dynamic moment of inertia for the band also decreases continuously up to the highest observed frequencies. These results, along with the predictions of a total Routhian surface calculation, suggest that the ΔI=2 band in 111 Sn undergoes a change of shape from collective prolate to triaxial with increase in spin and possibly terminates in a noncollective oblate state at a high spin

Behavior and reproductive success of Rock Sandpipers breeding on the Yukon-Kuskokwim River Delta, Alaska

NARCIS (Netherlands)

Johnson, Matthew; Conklin, J.R.; Johnson, Branden; McCaffery, Brian J.; Haig, Susan M.; Walters, Jeffrey R.

2009-01-01

We studied Rock Sandpiper (Calidris ptilocnemis) breeding behavior and monitored reproductive success from 1998 to 2005 on the Yukon-Kuskokwim River Delta, Alaska, USA. We banded 24 adults and monitored 45 nests. Annual return rate of adults ranged between 67 and 100%. Six pairs of Rock Sandpipers

Band-to-band transitions, selection rules, effective mass, and excitonic contributions in monoclinic β -Ga2O3

Science.gov (United States)

Mock, Alyssa; Korlacki, Rafał; Briley, Chad; Darakchieva, Vanya; Monemar, Bo; Kumagai, Yoshinao; Goto, Ken; Higashiwaki, Masataka; Schubert, Mathias

2017-12-01

We employ an eigenpolarization model including the description of direction dependent excitonic effects for rendering critical point structures within the dielectric function tensor of monoclinic β -Ga2O3 yielding a comprehensive analysis of generalized ellipsometry data obtained from 0.75-9 eV. The eigenpolarization model permits complete description of the dielectric response. We obtain, for single-electron and excitonic band-to-band transitions, anisotropic critical point model parameters including their polarization vectors within the monoclinic lattice. We compare our experimental analysis with results from density functional theory calculations performed using the Gaussian-attenuation-Perdew-Burke-Ernzerhof hybrid density functional. We present and discuss the order of the fundamental direct band-to-band transitions and their polarization selection rules, the electron and hole effective mass parameters for the three lowest band-to-band transitions, and their excitonic contributions. We find that the effective masses for holes are highly anisotropic and correlate with the selection rules for the fundamental band-to-band transitions. The observed transitions are polarized close to the direction of the lowest hole effective mass for the valence band participating in the transition.

High-resolution far-infrared synchrotron FTIR spectrum of the ν12 band of formamide-d1 (DCONH2)

Science.gov (United States)

Tan, T. L.; Wu, Q. Y.; Ng, L. L.; Appadoo, Dominique R. T.; McNaughton, Don

2018-05-01

The spectrum of the ν12 band of formamide-d1 (DCONH2) was recorded using a synchrotron Fourier transform infrared (FTIR) spectrometer coupled to the Australian Synchrotron THz/Far-IR beamline, with an unapodized resolution of 0.00096 cm-1 in the 350-210 cm-1 region. For the first time, rovibrational constants up to five quartic and two sextic terms were derived for the v12 = 1 state through the fitting of a total of 2072 far-infrared transitions using Watson's A-reduced Hamiltonian in the Ir representation with a root-mean-square (rms) deviation of 0.000073 cm-1. The band centre of the ν12 band of DCONH2 was found to be 289.3327553(47) cm-1 although the experimental uncertainty was limited to ±0.0002 cm-1. Ground state rovibrational constants of DCONH2 up to five quartic and two sextic constants were derived from a fit of 847 ground state combination differences (GSCDs) obtained from the infrared transitions of the ν12 band, together with 6 previously reported microwave transitions, with a rms deviation of 0.000108 cm-1. The ground state rotational constants (A, B, and C) of DCONH2 were improved while the ground state centrifugal distortion constants were accurately obtained for the first time. The uncertainty of the measured infrared lines was estimated to be ±0.0002 cm-1. From the ground state rotational constants, the inertial defect of DCONH2 was calculated to be 0.0169412(11) uÅ2.

Relativistic band-structure calculations for electronic properties of actinide dioxides

International Nuclear Information System (INIS)

Maehira, Takahiro; Hotta, Takashi

2007-01-01

Energy band structures of actinide dioxides AnO 2 (An=Th, U, Np, and Pu) are investigated by a relativistic linear augmented-plane-wave method with the exchange-correlation potential in a local density approximation (LDA). It is found in common that the energy bands in the vicinity of the Fermi level are mainly due to the hybridization between actinide 5f and oxygen 2p electrons. By focusing on the crystalline electric field states, we point out the problem in the application of the LDA to AnO 2

The [U{sub 2}F{sub 12}]{sup 2-} anion of Sr[U{sub 2}F{sub 12}

Energy Technology Data Exchange (ETDEWEB)

Scheibe, Benjamin; Pietzonka, Clemens; Conrad, Matthias; Kraus, Florian [Fachbereich Chemie, Philipps-Universitaet Marburg (Germany); Mustonen, Otto; Karppinen, Maarit; Karttunen, Antti J. [Department of Chemistry, Aalto University (Finland); Atanasov, Mihail; Neese, Frank [Max-Planck Institute for Chemical Energy Conversion, Muelheim an der Ruhr (Germany)

2018-03-05

The D{sub 2h}-symmetric dinuclear complex anion [U{sub 2}F{sub 12}]{sup 2-} of pastel green Sr[U{sub 2}F{sub 12}] shows a hitherto unknown structural feature: The coordination polyhedra around the U atoms are edge-linked monocapped trigonal prisms, the U{sup V} atoms are therefore seven-coordinated. This leads to a U-U distance of 3.8913(6) Aa. A weak U{sup V}-U{sup V} interaction is observed for the dinuclear [U{sub 2}F{sub 12}]{sup 2-} complex and described by the antiferromagnetic exchange J{sub exp} of circa -29.9 cm{sup -1}. The crystalline compound can be easily prepared from SrF{sub 2} and β-UF{sub 5} in anhydrous hydrogen fluoride (aHF) at room temperature. It was studied by means of single crystal X-ray diffraction, IR, Raman and UV/VIS spectroscopy, magnetic measurements, and by molecular as well as by solid-state quantum chemical calculations. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Evolution of the Mazatzal province and the timing of the Mazatzal orogeny: Insights from U-Pb geochronology and geochemistry of igneous and metasedimentary rocks in southern New Mexico

Science.gov (United States)

Amato, J.M.; Boullion, A.O.; Serna, A.M.; Sanders, A.E.; Farmer, G.L.; Gehrels, G.E.; Wooden, J.L.

2008-01-01

New U-Pb zircon ages, geochemistry, and Nd isotopic data are presented from three localities in the Paleoproterozoic Mazatzal province of southern New Mexico, United States. These data help in understanding the source regions and tectonic setting of magmatism from 1680 to 1620 Ma, the timing of the Mazatzal orogeny, the nature of postorogenic maginatism, Proterozoic plate tectonics, and provide a link between Mazatzal subblocks in Arizona and northern New Mexico. The data indicate a period from 1680 to 1650 Ma in which juvenile felsic granitoids were formed, and a later event between 1646 and 1633 Ma, when these rocks were deformed together with sedimentary rocks. No evidence of pre-1680 Ma rocks or inherited zircons was observed. The igneous rocks have ENd(t) from -1.2 to +4.3 with most between +2 and +4, suggesting a mantle source or derivation from similar-aged crust. Nd isotope and trace element concentrations are consistent with models for typical are magmatism. Detrital zircon ages from metasedimentary rocks indicate that sedimentation occurred until at least 1646 Ma. Both local and Yavapai province sources contributed to the detritus. All of the samples older than ca. 1650 Ma are deformed, whereas undeformed porphyroblasts were found in the contact aureole of a previously dated 1633 Ma gabbro. Regionally, the Mlazatzal orogeny occurred mainly between 1654 and 1643 Ma, during final accretion of a series of island arcs and intervening basins that may have amalgamated offshore. Rhyolite magmatism in the southern Mazatzal province was coeval with gabbro intrusions at 1633 Ma and this bimodal magmatism may have been related to extensional processes following arc accretion. ?? 2007 Geological Society of America.

77 FR 20716 - Drawbridge Operation Regulation; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2012-04-06

... issued a temporary deviation from the regulation governing the operation of the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois. The deviation...) 366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island Arsenal requested a temporary deviation...

77 FR 3607 - Drawbridge Operation Regulation; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2012-01-25

... issued a temporary deviation from the regulation governing the operation of the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois. The deviation...) 366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island Arsenal requested a temporary deviation...

75 FR 17561 - Drawbridge Operation Regulations; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2010-04-07

... issued a temporary deviation from the regulation governing the operations of the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, Mile 482.9, Rock Island, Illinois. The deviation is... Manager, Docket Operations, telephone (202) 366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island...

76 FR 9223 - Drawbridge Operation Regulation; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2011-02-17

... issued a temporary deviation from the regulation governing the operation of the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois. The deviation...) 366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island Arsenal requested a temporary deviation...

75 FR 22228 - Drawbridge Operation Regulations; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2010-04-28

... issued a temporary deviation from the regulation governing the operation of the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, Mile 482.9, Rock Island, Illinois. The deviation is... Manager, Docket Operations, telephone (202) 366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island...

77 FR 5398 - Drawbridge Operation Regulation; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2012-02-03

... issued a temporary deviation from the regulation governing the operation of the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois. The deviation...) 366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island Arsenal requested a temporary deviation...

75 FR 68974 - Drawbridge Operation Regulation; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2010-11-10

..., has issued a temporary deviation from the regulation governing the operation of the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois... Operations, telephone 202-366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island Arsenal requested a...

The possibility of the mixed valence state in the uranium intermetallic compounds: UCoGa5, U2Ru2Sn and U2RuGa8

International Nuclear Information System (INIS)

Troc, Robert

2007-01-01

The mixed valence (MV) phenomenon has been observed so far in a large number of various compounds but containing only lanthanides. These properties are usually associated with the mixing of the localised f-state and the band states. The usual valence state for magnetic uranium intermetallics is the trivalent state 5f 3 or hybridised 5f 2 6d 1 , both are nearly degenerate in energy and can compete for a stability of the compound. In some cases a gain in an energy minimum may be achieved by very fast fluctuating between these two states with a time of 10 -14 s, which does not allow to yield the ordered state even if the exchange interactions (favourite the U-U distances) would be able for that. The latter cases seem to concern the described here intermetallics: one ternary compound based on Co, UCoGa 5 , and the two uranium ternary compounds based on Ru, namely U 2 Ru 2 Sn and U 2 RuGa 8 which all crystallize in a tetragonal unit cell. All these compounds show a maximum in their temperature dependences of the magnetic susceptibility measured along and perpendicular to the c-axis. Such a behaviour, which is reminiscent of a number of Ce (Sm, Eu) and Yb compounds for which χ(T) has in the past been considered by Sales and Wohlleben (SW) by applying their ICF model or by Lawrance et al. following their scaling procedure. It turned out that these phenomenological models can also be applied to the considered here two Ru-based uranium ternaries from which some reliable energy parameters could be found. In order to further support the mixing valence scenario for the first such cases in uranium compounds presented here, the transport and thermodynamic properties are also discussed. However, some of the most important results confirming the MV state, e.g., in U 2 RuGa 8 , has recently been achieved from the inelastic neutron scattering performed in the Rutherford Appleton Laboratory on the ISIS facility. From these measurements a characteristic gap of 60 meV has been

Electronic structure calculation of Sr2CoWO6 double perovskite using DFT+U

Science.gov (United States)

Mandal, Golak; Jha, Dhiraj; Himanshu, A. K.; Ray, Rajyavardhan; Mukherjee, P.; Das, Nisith; Singh, B. K.; Sreenivas, K.; Singh, M. N.; Sinha, A. K.

2018-04-01

Using the synchrotron and Raman spectroscopy we measured the lattice parameter and Raman modes of the half-metallic (HM) Sr2CoWO6 (SCoW) synthesied by the solid state reaction technique.. The physical properties of SCoW are studies within the framework of density function theory (DFT) under the generalised gradient approximation (GGA) of Perdew, Bruke, and Ernzerhof both by itself and including a coulomb repulsion via the Hubbard approach or GGA+U. Our results states that Sr2CoWO6 material behaves as insulators for the spin-up orientation and spindown orientation as found for the half metallic systems and at U = 0.06eV the ground state of spin up channel being insulating with spin gap of 2.27eV comparable to the experimental Band gap (BG).

Energy Efficiency, Water Efficiency, and Renewable Energy Site Assessment: Seneca Rocks Discovery Center, Seneca Rocks, West Virginia

Energy Technology Data Exchange (ETDEWEB)

Kiatreungwattana, Kosol [National Renewable Energy Lab. (NREL), Golden, CO (United States); Salasovich, James [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kandt, Alicen [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-03-22

As part of ongoing efforts by the U.S. Forest Service to reduce energy use and incorporate renewable energy technologies into its facilities, the Department of Energy's National Renewable Energy Laboratory performed an energy efficiency and renewable energy site assessment of the Seneca Rocks Discovery Center in Seneca Rocks, West Virginia. This report documents the findings of this assessment, and provides site-specific information for the implementation of energy and water conservation measures, and renewable energy measures.

Uranium in waters and aquifer rocks at the Nevada Test Site, Nye County, Nevada

International Nuclear Information System (INIS)

Zielinski, R.A.; Rosholt, J.N.

1978-01-01

Previous chemical, geological, and hydrological information describing the physical and chemical environment of the Nevada Test Site has been combined with new radiochemical and isotope data for water and rock samples in order to explain the behavior of uranium during alteration of thick sequences of rhyolitic volcanic rocks and associated volcanielastic sediments. A model is proposed in which uranium mobility is controlled by two competing processes. Uranium is liberated from the volcanic rocks through dissolution of the glassy constituents and is carried in solution as a uranyl carbonate complex. Uranium is subsequently removed from solution by adsorption on secondary oxides of iron, titanium, and manganese, as observed in fission-track maps of aquifer rocks. The model explains the poor correlation of dissolved uranium with depth within tuffaceous sequences in which percolation of ground water is predominantly downward. Good positive correlation of dissolved uranium with dissolved Na, total dissolved solids, and total carbonate supports the glass dissolution model, while inverse correlation of dissolved uranium with 234 U/ 238 U ratios of water implies uranium is being absorbed by a relatively insoluble, surficial phase. Alpha radioactivity of Test Site water is primarily caused by high 234 U contents, and beta activity is highly correlated with dissolved K ( 40 K). Smallamounts of dissolved radium, 216 Pb, and 210 Po are present but no evidence was found for alpha activity sources related to nuclear testing (Pu, 235 U). A filtered but unacidified carbonate solution of uranium was found to be stable (+-10 percent of original U concentration) for years when stored in acid-washed polyethylene bottles. 5 tables, 2 figs

Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite

Science.gov (United States)

Aleinikoff, J.N.; Schenck, W.S.; Plank, M.O.; Srogi, L.A.; Fanning, C.M.; Kamo, S.L.; Bosbyshell, H.

2006-01-01

High-grade rocks of the Wilmington Complex, northern Delaware and adjacent Maryland and Pennsylvania, contain morphologically complex zircons that formed through both igneous and metamorphic processes during the development of an island-arc complex and suturing of the arc to Laurentia. The arc complex has been divided into several members, the protoliths of which include both intrusive and extrusive rocks. Metasedimentary rocks are interlayered with the complex and are believed to be the infrastructure upon which the arc was built. In the Wilmingto n Complex rocks, both igneous and metamorphic zircons occur as elongate and equant forms. Chemical zoning, shown by cathodoluminescence (CL), includes both concentric, oscillatory patterns, indicative of igneous origin, and patchwork and sector patterns, suggestive of metamorphic growth. Metamorphic monazites are chemically homogeneous, or show oscillatory or spotted chemical zoning in backscattered electron images. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date complexly zoned zircon and monazite. All but one member of the Wilmington Complex crystallized in the Ordovician between ca. 475 and 485 Ma; these rocks were intruded by a suite of gabbro-to-granite plutonic rocks at 434 ?? Ma. Detrital zircons in metavolcanic and metasedimentary units were derived predominantly from 0.9 to 1.4 Ga (Grenvillian) basement, presumably of Laurentian origin. Amphibolite to granulite facies metamorphism of the Wilmington Complex, recorded by ages of metamorphic zircon (428 ?? 4 and 432 ?? 6 Ma) and monazite (429 ?? 2 and 426 ?? 3 Ma), occurred contemporaneously with emplacement of the younger plutonic rocks. On the basis of varying CL zoning patterns and external morphologies, metamorphic zircons formed by different processes (presumably controlled by rock chemistry) at slightly different times and temperatures during prograde metamorphism. In addition, at least three other thermal episodes are

Rett Syndrome Mutant Neural Cells Lacks MeCP2 Immunoreactive Bands.

Directory of Open Access Journals (Sweden)

Carlos Bueno

Full Text Available Dysfunctions of MeCP2 protein lead to various neurological disorders such as Rett syndrome and Autism. The exact functions of MeCP2 protein is still far from clear. At a molecular level, there exist contradictory data. MeCP2 protein is considered a single immunoreactive band around 75 kDa by western-blot analysis but several reports have revealed the existence of multiple MeCP2 immunoreactive bands above and below the level where MeCP2 is expected. MeCP2 immunoreactive bands have been interpreted in different ways. Some researchers suggest that multiple MeCP2 immunoreactive bands are unidentified proteins that cross-react with the MeCP2 antibody or degradation product of MeCP2, while others suggest that MeCP2 post-transcriptional processing generates multiple molecular forms linked to cell signaling, but so far they have not been properly analyzed in relation to Rett syndrome experimental models. The purpose of this study is to advance understanding of multiple MeCP2 immunoreactive bands in control neural cells and p.T158M MeCP2e1 mutant cells. We have generated stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Application of N- and C- terminal MeCP2 antibodies, and also, RFP antibody minimized concerns about nonspecific cross-reactivity, since they react with the same antigen at different epitopes. We report the existence of multiple MeCP2 immunoreactive bands in control cells, stable wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Also, MeCP2 immunoreactive bands differences were found between wild-type and p.T158M MeCP2e1-RFP mutant expressing cells. Slower migration phosphorylated band around 70kDa disappeared in p.T158M MeCP2e1-RFP mutant expressing cells. These data suggest that threonine 158 could represent an important phosphorylation site potentially involved in protein function. Our results clearly indicate that MeCP2 antibodies have no cross-reactivity with similar epitopes on others proteins, supporting the

Modification of band gaps and optoelectronic properties of binary calcium chalcogenides by means of doping of magnesium atom(s) in rock-salt phase- a first principle based theoretical initiative

Science.gov (United States)

Debnath, Bimal; Sarkar, Utpal; Debbarma, Manish; Bhattacharjee, Rahul; Chattopadhyaya, Surya

2018-02-01

The band gaps and optoelectronic properties of binary calcium chalcogenide semiconductors have been modified theoretically by doping magnesium atom(s) into their respective rock-salt unit cells at some specific concentrations x = 0.0, 0.25, 0.50, 0.75 and 1.0 and confirmed such modifications by studying their structural, electronic and optical properties using DFT based FP-LAPW approach. The WC-GGA functional is used to calculate structural properties, while mBJ, B3LYP and WC-GGA are used for calculating electronic and optical properties. The concentration dependences of lattice parameter, bulk modulus and fundamental band gap for each alloy system exhibit nonlinearity. The atomic and orbital origin of different electronic states in the band structure of each compound are explored from its density of states (DOS). The microscopic origin of band gap bowing for each of the alloy systems is explored in terms of volume deformation, charge exchange and structural relaxation. The chemical bonds between the constituent atoms in each compound are found as ionic in nature. Optical properties of each specimen are calculated from its computed spectra of dielectric function, refractive index, extinction coefficient, normal incidence reflectivity, optical conductivity, optical absorption and energy loss function. Several calculated results have been compared with available experimental and other theoretical data.

78 FR 18933 - Drawbridge Operation Regulations; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2013-03-28

... operating schedule that governs the Rock Island Railroad and Highway Drawbridge across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois. The deviation is necessary to allow the Quad City Marathon..., Docket Operations, telephone (202) 366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island Arsenal...

Band crossings in mercury nuclei: effect of occupation of i13/2 neutron orbits

International Nuclear Information System (INIS)

Khadkikar, S.B.; Praharaj, C.R.

1984-04-01

The K=0 + ground band and two rotation-aligned bands (K=1 + or K2 + two quasi-particle band and K=2 + four quasi-particle band) are studied in 198 Hg, 194 Hg and 190 Hg by angular momentum projection from Hartree-Fock and particle-hole intrinsic states. There is a first anomaly in these three nuclei around 8(h/2π) due to the crossing of the ground band and the two quasi-particle band. Because of the nature of occupation of i13/2 orbitals the four quasi-particle band is too highlying in 198 Hg and does not cross the two quasi-particle bands, while such a second crossing occurs in 194 Hg and 190 Hg near 20 (h/2π). (author)

Vector coherent state representations of SO5 contains SU2 + SU2 contains U1 + U1 and SO5 contains U1 + U1

International Nuclear Information System (INIS)

Pan Feng

1991-01-01

VCS representations of SO 5 contains SU 2 + SU 2 contains U 1 + U 1 and SO 5 contains U 1 + U 1 are discussed. Reduced matrix elements for SO 5 contains SU 2 + SU 2 are derived. The multiplicity of a weight for SO 5 is determined by using the K-matrix technique

Spectroscopic techniques for assessing the possible use of phosphate rock by-products for the removal of trace elements in soils.

Science.gov (United States)

Martinez-Sanchez, M. J.; Perez-Sirvent, C.; Garcia-Lorenzo, M. L.; Bech, J.; Hernandez-Cordoba, M.

2012-04-01

The production of fertilizers from apatite results in the obtention of considerable amounts of phosphate rock byproducts, representing a serious environmental problem. In addition, soil contamination with heavy metals due to mining or metallurgical activities is a severe environmental problem, increased when soil use is changed to agricultural or urban uses. The aim of this work was to study the possibility of using phosphate rock byproducts for the in situ treatment of soils polluted by heavy metals, allowing to revalorise phosphate rock residues and at the same time, providing a low-cost solution for the contaminated soil. The following methodologies were applied in order to characterise minerals phases present in phosphate rock residues: Wavelength Dispersive X-Ray Spectrometry (WDXRF), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectrometry (EDS), thermogravimetry (TG) and Fourier Transform Infrared Spectroscopy (FTIR). The results obtained showed that the samples studied had a fine texture, showing average contents of 71%, 24% of sand and 5% for silt, sand and clay, respectivaly. In addition, these materials showed basic-neutral pH values (7.5-9) and a cationic interchange capacity of 20.4 meq/100g. Studied samples showed a 22% of carbonates and a 13% of apatite in their composition and all of them showed 4 bands at 1.100, 1.044, 674 y 576 cm-1, corresponding to P-O vibrations in PO4 groups. OH band vibrations appeared at 3.700-3.550 cm-1, and detected band at 3.400 cm-1 and 633 cm-1 could correspond to occluded water. On the other hand, detected bands at 1.460-1.430, 874 cm-1 suggested the presence of CaCO3 and carbonates in the apatite. After sample characterization, the performance of these residues to adsorb trace element ions (Cd+2 and Pb+2) from acidic aqueous solutions (simulating acidic mine drainage) was studied. The use of spectroscopic techniques after mixing soils and phosphate rock products demonstrate that these residues could be

Optimization of photometric determination of U with arsenazo III for direct determination of U in steels, soils and waters

International Nuclear Information System (INIS)

Kosturiak, A.; Talanova, A.; Rurikova, D.; Kalavska, D.

1984-01-01

Conditions were optimized for the reaction of U(VI) with arsenazo III. Recommended as the optimal medium for photometric determination of uranium in the concentration range 0.5 to 50 μg U/ml was the glycine buffer with pH 1.2 to 2.2. The results of the suggested method have better reproducibility than those of the mineral acid procedure used so far. Complexone III should be added to mask the other cations accompanying uranium in steels, waters and rocks. (author)

78 FR 15292 - Drawbridge Operation Regulations; Upper Mississippi River, Rock Island, IL

Science.gov (United States)

2013-03-11

... schedule that governs the Rock Island Railroad and Highway Drawbridge, across the Upper Mississippi River, mile 482.9, at Rock Island, Illinois. The deviation is necessary to allow the River Bandits 5K Run/Walk...) 366-9826. SUPPLEMENTARY INFORMATION: The U.S. Army Rock Island Arsenal requested a temporary deviation...

Radiological impact of natural radioactivity in Egyptian phosphate rocks, phosphogypsum and phosphate fertilizers

International Nuclear Information System (INIS)

El-Bahi, S.M.; Sroor, A.; Mohamed, Gehan Y.; El-Gendy, N.S.

2017-01-01

In this study, the activity concentrations of the natural radionuclides in phosphate rocks and its products were measured using a high- purity germanium detector (HPGe). The obtained activity results show remarkable wide variation in the radioactive contents for the different phosphate samples. The average activity concentration of "2"3"5U, "2"3"8U, "2"2"6Ra, "2"3"2Th and "4"0K was found as (45, 1031, 786, 85 and 765 Bq/kg) for phosphate rocks, (28, 1234, 457, 123 and 819 Bq/kg) for phosphate fertilizers, (47, 663, 550, 79 and 870 Bq/kg) for phosphogypsum and (25, 543, 409, 54 and 897 Bq/kg) for single super phosphate respectively. Based on the measured activities, the radiological parameters (activity concentration index, absorbed gamma dose rate in outdoor and indoor and the corresponding annual effective dose rates and total excess lifetime cancer risk) were estimated to assess the radiological hazards. The total excess lifetime cancer risk (ELCR) has been calculated and found to be high in all samples, which related to high radioactivity, representing radiological risk for the health of the population. - Highlights: • Level of radioactivity of phosphate rocks and by-products samples. • The radiological health hazard parameters. • Radiological risk to the health of the population. • The excess lifetime cancer risk factor.

Correlation of the activity of the 238 U in soil and 222 Rn in domiciles, with the rocks of cities of the Estado de Chihuahua

International Nuclear Information System (INIS)

Colmenero S, L.; Villalba, L.; Montero C, M.E.

2004-01-01

The state of Chihuahua has numerous locations of uranium, being Pena Blanca the great and more important location of the country. Diverse rock types with important quantities of uranium are distributed by the whole state. The igneous extrusive acid rocks are those that have bigger quantity of uranium, like they are the rhyolites and dacites and these rocks are located in enough proportion by the whole state. Some of the main cities of the state are near to locations or uraniferous rocks, as Aldama, Nuevo Casas Grandes, Chihuahua, Jimenez and Bocoyna, other important cities are not near important locations. It was determined specific activity by gamma spectroscopy of the series of the 238 U in soils and determination of the radon concentration in domiciles of the main cities of the state. They were found high specific activity values in soil in eight of the thirteen analyzed cities and important radon concentrations in three cities. It was found relationship among the specific activity in soil in near cities to uraniferous locations. (Author)

Music and subversion in Tom Stoppard's rock 'n'roll

OpenAIRE

Matos, Susana Isabel Mendes de

2013-01-01

This dissertation aims at analysing music as a form of subversion in Tom Stoppard’s play Rock ‘N’ Roll. After a short summary of Stoppard’s career, the bands and songs chosen by him are analysed from the perspective of subversion against censorship and totalitarian regimes, relating them to the plot. The dissertation also focuses on the specific case of the Czech band the Plastic People of the Universe and its importance to the history of Czechoslovakia between 1968 and 1990. O presente tr...

U-Pb zircon geochronology of Mesoproterozoic postorogenic rocks and implications for post-Ottawan magmatism and metallogenesis, New Jersey Highlands and contiguous areas, USA

Science.gov (United States)

Volkert, R.A.; Zartman, R.E.; Moore, P.B.

2005-01-01

Postorogenic rocks are widespread in Grenville terranes of the north-central Appalachians where they form small, discordant, largely pegmatitic felsic intrusive bodies, veins, and dikes, and also metasomatic calcic skarns that are unfoliated and postdate the regional 1090 to 1030 Ma upper amphibolite- to granulite-facies metamorphism related to the Grenville (Ottawan) Orogeny. Zircons from magmatic and nonmagmatic rocks from northern New Jersey and southern New York were dated to provide information on the regional tectonomagmatic and metallogenic history following Ottawan orogenesis. We obtained U-Th-Pb zircon ages of 1004 ?? 3 Ma for pegmatite associated with the 1020 ?? 4 Ma Mount Eve Granite near Big Island, New York, 986 ?? 4 Ma for unfoliated, discordant pegmatite that intrudes supracrustal marble at the Buckwheat open cut, Franklin, New Jersey, ???990 Ma for a silicate-borate skarn layer in the Franklin Marble at Rudeville, New Jersey, and 940 ?? 2 Ma for a calc-silicate skarn layer at Lower Twin Lake, New York. This new data, together with previously published ages of 1020 ?? 4 to 965 ?? 10 Ma for postorogenic rocks from New Jersey and southern New York, provide evidence of magmatic activity that lasted for up to 60 Ma past the peak of high-grade metamorphism. Postorogenic magmatism was almost exclusively felsic and involved relatively small volumes of metaluminous to mildly peraluminous melt that fractionated from an A-type granite parent source. Field relationships suggest the melts were emplaced along lithosphere-scale fault zones in the Highlands that were undergoing extension and that emplacement followed orogenic collapse by least 30 Ma. Postorogenic felsic intrusions correspond to the niobium-yttrium-fluorine (NYF) class of pegmatites of C??erny?? (1992a). Geochronologic data provide a temporal constraint on late-stage hydrothermal activity and a metallogenic event in New Jersey at ???990 to 940 Ma that mineralized pegmatites with subeconomic to

U-234/U-238 ratio: Qualitative estimate of groundwater flow in Rocky Flats monitoring wells

International Nuclear Information System (INIS)

Laul, J.C.

1994-01-01

Groundwater movement through various pathways is the primary mechanism for the transport of radionuclides and trace elements in a water/rock interaction. About three dozen wells, installed in the Rocky Flats Plant (RFP) Solar Evaporation Ponds (SEP) area, are monitored quarterly to evaluate the extent of any lateral and downgradient migration of contaminants from the Solar Evaporation Ponds: 207-A; 207-B North, 207-B Center, and 207-B South; and 207-C. The Solar Ponds are the main source for the various contaminants: radionuclides (U-238, U-234, Pu-239, 240 and Am-241); anions; and trace metals to groundwaters. The U-238 concentrations in Rocky Flats groundwaters vary from 2 (CO 3 ) 2 2- , because of the predominant bicarbonate medium

A study of U-Pb isotopic evolutionary system in Chanziping uranium deposit

International Nuclear Information System (INIS)

Xu Weichang; Huang Shijie; Xia Yuliang.

1988-01-01

Chanziping uranium deposit occurred in the black siliceous slate of Lower cambrian. The uranium mineralization was controlled by both interstratified fault belt and the ore-bearing beds. Based on the study of the U-Pb isotopic system of the various rocks, ores and minerals in the ore-bearing beds, the authors find out the obvious disequilibrium of U-Pb isotopic composition in most rock samples which indicates the loss of uranium form the ore-bearing beds and surrounding granite. Its counting loss ranges from 30 to 80%. The age of rich ores of the U-Pb concordance diagram and the U-Pb three stage model are t 1 = 523 ± 19M. Y. , t 2 = 22 ± 2 M.Y.. The isochronal ages for pitchblend are 75 ± 4 M.Y., 43 ± 7 M.Y., and for rock is 416 M.y.. These data shows that the uranium in ore-bearing beds was mainly derived from the ore-bearing beds itself and partly from the surrounding granite. The ore deposit can be considered to be of stratabound uranium deposit of sedimentation and late transformation type

Nature of the valence band states in Bi2(Ca, Sr, La)3Cu2O8

International Nuclear Information System (INIS)

Wells, B.O.; Lindberg, P.A.P.; Shen, Z.; Dessau, D.S.; Spicer, W.E.; Lindau, I.; Mitzi, D.B.; Kapitulnik, A.

1990-01-01

We have used photoemission spectroscopy to examine the symmetry of the occupied states of the valence band for the La doped superconductor Bi 2 (Ca, Sr, La) 3 Cu 2 O 8 . While the oxygen states near the bottom of the 7 eV wide valence band exhibit predominantly O 2p z symmetry, the states at the top of the valence band extending to the Fermi level are found to have primarily O 2p x and O 2p y character. We have also examined anomalous intensity enhancements in the valence band feature for photon energies near 18 eV. These enhancements, which occur at photon energies ranging from 15.8 to 18.0 eV for the different valence band features, are not consistent with either simple final state effects or direct O2s transitions to unoccupied O2p states

Natural radioactivity of the rocks from the Moon and planets

Energy Technology Data Exchange (ETDEWEB)

Surkov, Yu.A. (AN SSSR, Moscow. Inst. Geokhimii i Analiticheskoj Khimii)

1982-01-01

Tha data on natural radioactivity of rocks (U, Th and K contents) from the Moon, Venus and Mars obtained by means of cosmic means are analyzed. The Moon rock radioactivity has been measured in situ (from orbital vehicles) as well as in the samples of lunar material delivered to the Earth and as for Venus and Mars rocks - by landing vehicles. It has been found that the main specific feature of the Moon and the Earth group planets is the presence of two geomorphological types of the structure of their surface composed by two different types of the matter. The ancient continent regions are made up by feldspar rock - gabbroanorthosite at the Moon (and possibly at the Mars) and granite-metamorphic at the Earth (and possibly at the Venus). The younger ''marine'' regions are composed by basalt rock. The presence at the Moon of two types of crust (marine and continental ones) having a different nature is clearly reflected on the Moon radioactivity map where marine regions (15% of the total surface) which have high radioactivity and continental regions with a relatively low radioactivity can be seen. The discovery of rocks on the Venus surface highly enriched by U, Th and K speaks of their melting from the primary matter in the depth of the Earth. The Marsian rock by the natural radioelement content is close to igneous rocks of the Earth crust of the basic composition and lunar marine basalts.

Natural radioactivity of the rocks from the Moon and planets

International Nuclear Information System (INIS)

Surkov, Yu.A.

1982-01-01

Tha data on natural radioactivity of rocks (U, Th and K contents) from the Moon, Venus and Mars obtained by means of cosmic means are analyzed. The Moon rock radioactivity has been measured in situ (from orbital vehicles) as well as in the samples of lunar material delivered to the Earth and as for Venus and Mars rocks - by landing vehicles. It has been found that the main specific feature of the Moon and the Earth group planets is the presence of two geomorphological types of the structure of their surface composed by two different types of the matter. The ancient contineent regions are made up by feldspar rock - gabbroanorthosite at the Moon (and possibly at the Mars) and granite-metamorphic at the Earth (and possibly at the Venus). The younger ''marine'' regions are composed by basalt rock. The presence at the Moon of two types of crust (marine and continental ones) having a different nature is clearly reflected on the Moon radioactivity map where marine regions (15% of the total surface) which have high radioactivity and continental regions with a relatively low radioactivity can be seen. The discovery of rocks on the Venus surface highly enriched by U, Th and K speaks of their melting from the primary matter in the depth of the Earth. The Marsian rock by the natural radioelement content is close to igneous rocks of the Earth crust of the basic composition and lunar marine basalts

Band Alignment of 2D Transition Metal Dichalcogenide Heterojunctions

KAUST Repository

Chiu, Ming-Hui

2016-09-20

It is critically important to characterize the band alignment in semiconductor heterojunctions (HJs) because it controls the electronic and optical properties. However, the well-known Anderson\\'s model usually fails to predict the band alignment in bulk HJ systems due to the presence of charge transfer at the interfacial bonding. Atomically thin 2D transition metal dichalcogenide materials have attracted much attention recently since the ultrathin HJs and devices can be easily built and they are promising for future electronics. The vertical HJs based on 2D materials can be constructed via van der Waals stacking regardless of the lattice mismatch between two materials. Despite the defect-free characteristics of the junction interface, experimental evidence is still lacking on whether the simple Anderson rule can predict the band alignment of HJs. Here, the validity of Anderson\\'s model is verified for the 2D heterojunction systems and the success of Anderson\\'s model is attributed to the absence of dangling bonds (i.e., interface dipoles) at the van der Waal interface. The results from the work set a foundation allowing the use of powerful Anderson\\'s rule to determine the band alignments of 2D HJs, which is beneficial to future electronic, photonic, and optoelectronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Band-gap narrowing of TiO2 films induced by N-doping

International Nuclear Information System (INIS)

Nakano, Y.; Morikawa, T.; Ohwaki, T.; Taga, Y.

2006-01-01

N-doped TiO 2 films were deposited on n + -GaN/Al 2 O 3 substrates by reactive magnetron sputtering and subsequently crystallized by annealing at 550 o C in flowing N 2 gas. The N-doping concentration was ∼8.8%, as determined from X-ray photoelectron spectroscopy measurements. Deep-level optical spectroscopy measurements revealed two characteristic deep levels located at 1.18 and 2.48 eV below the conduction band. The 1.18 eV level is probably attributable to the O vacancy state and can be active as an efficient generation-recombination center. Additionally, the 2.48 eV band is newly introduced by the N-doping and contributes to band-gap narrowing by mixing with the O 2p valence band

A simple source preparation method for alpha-ray spectrometry of volcanic rock sample

International Nuclear Information System (INIS)

Takahashi, Masaomi; Kurihara, Yuichi; Sato, Jun

2006-01-01

A simple source preparation method was developed for the alpha-ray spectrometry to determine U and Th in volcanic rockes. Isolation of U and Th from volcanic rocks was made by use of UTEVA-Spec. resin, extraction chromatograph material. U and Th were extracted by TTA-benzene solution and organic phase was evaporated drop by drop on a hot stainless steel planchet to dryness. This method was found to be effective for the preparation of sources for alpha-ray spectrometry. (author)

Chemical, multispectral, and textural constraints on the composition and origin of rocks at the Mars Pathfinder landing site

Science.gov (United States)

McSween, H.Y.; Murchie, S.L.; Crisp, J.A.; Bridges, N.T.; Anderson, R.C.; Bell, J.F.; Britt, D.T.; Brückner, J.; Dreibus, G.; Economou, T.; Ghosh, A.; Golombek, M.P.; Greenwood, J.P.; Johnson, J. R.; Moore, H.J.; Morris, R.V.; Parker, T.J.; Rieder, R.; Singer, R.; Wänke, H.

1999-01-01

of a "1 μm" pyroxene absorption band. Plausible explanations include impact glass, band masking by magnetite, or presence of calcium- and iron-rich pyroxenes and olivine which push the absorption band minimum past the imager's spectral range. The inferred andesitic composition is most similar to terrestrial anorogenic icelandites, formed by fractionation of tholeiitic basaltic magmas. Early melting of a relatively primitive Martian mantle could produce an appropriate parent magma, supporting the ancient age of Pathfinder rocks inferred from their incorporation in Hesperian flood deposits. Although rocks of andesitic composition at the Pathfinder site may represent samples of ancient Martian crust, inferences drawn about a necessary role for water or plate tectonics in their petrogenesis are probably unwarranted.

Location of the valence band maximum in the band structure of anisotropic 1 T'-ReSe2

Science.gov (United States)

Eickholt, P.; Noky, J.; Schwier, E. F.; Shimada, K.; Miyamoto, K.; Okuda, T.; Datzer, C.; Drüppel, M.; Krüger, P.; Rohlfing, M.; Donath, M.

2018-04-01

Transition-metal dichalcogenides (TMDCs) are a focus of current research due to their fascinating optical and electronic properties with possible technical applications. ReSe2 is an interesting material of the TMDC family, with unique anisotropic properties originating from its distorted 1 T structure (1 T '). To develop a fundamental understanding of the optical and electric properties, we studied the underlying electronic structure with angle-resolved photoemission (ARPES) as well as band-structure calculations within the density functional theory (DFT)-local density approximation (LDA) and GdW approximations. We identified the Γ ¯M¯1 direction, which is perpendicular to the a axis, as a distinct direction in k space with the smallest bandwidth of the highest valence band. Using photon-energy-dependent ARPES, two valence band maxima are identified within experimental limits of about 50 meV: one at the high-symmetry point Z , and a second one at a non-high-symmetry point in the Brillouin zone. Thus, the position in k space of the global valence band maximum is undecided experimentally. Theoretically, an indirect band gap is predicted on a DFT-LDA level, while quasiparticle corrections lead to a direct band gap at the Z point.

The Effect of Early Diagenesis on the 238U/235U Ratio of Platform Carbonates.

Science.gov (United States)

Tissot, F.; Chen, C.; Go, B. M.; Naziemiec, M.; Healy, G.; Swart, P. K.; Dauphas, N.

2017-12-01

In the past 15 years, the so-called non-traditional stable isotopes systems (e.g., Mg, Fe, Mo, U) have emerged as powerful tracers of both high-T and low-T geochemical processes (e.g., [1]). Of particular interest for paleoredox studies is the ratio of "stable" isotopes of U (238U/235U), which has the potential to track the global extent of oceanic anoxia (e.g., [2, 3]). Indeed, in the modern ocean, U exists in two main oxidation states, soluble U6+ and insoluble U4+, and has a mean residence time of 400 kyr ([4]), much longer than the global ocean mixing time (1-2 kyr). As such the salinity-normalized ocean is homogeneous with regards to both U concentrations and isotopes (δ238USW = -0.392±0.005 ‰, [2]). The value of δ238USW at any given time is therefore the balance between U input to the ocean, mainly from rivers, and U removal, mostly into biogenic carbonates, anoxic/euxinic sediments and suboxic/hypoxic sediments (e.g., [2, 5]). Because the 238U/235U ratio of the past ocean cannot be measured directly, it has to be estimated from the measurement of the 238U/235U ratio of a sedimentary rock and assuming a constant fractionation factor. Carbonates appear as a promising record since they span most of Earth's history, and the δ238U values of modern primary carbonate precipitates and well-preserved fossil aragonitic coral up to 600 ka are indistinguishable from that of seawater (e.g., [2, 6, 7]). Yet, the effect of secondary processes on the δ238U values of non-coral carbonates, which represent the bulk of the rock record, has only been studied in a handful of shallow samples (down to 40cm, [6]) and remains poorly understood. To investigate the effect of early diagenesis on the 238U/235U ratio of carbonates on the 30kyr to 1Myr timescale, we measured δ13C, δ18O, and δ238U in samples from a 220m long drill core from the Bahamas carbonate platform. In order to separate lattice bound U from secondary U we developed a leaching protocol applicable to carbonate

Mapping of uranium and thorium in radioactive rocks using nuclear track solid detectors

International Nuclear Information System (INIS)

Bouch, C.M.

1982-01-01

α-Autoradiography and studies of induced fission in a research nuclear reactor (IEA-R1, IPEN, Sao Paulo) were done, employing Solid-State Nuclear Track detectors, in order to study the distribution of α-emitters, U and Th in rocks. Polished sections of rocks were prepared and photographed. Etching conditions were studied in order to adapt the detectors to the studies of microdistribution and macrodistribution of tracks. Polycarbonate foils (Bayer, Makrofol) were chosen as fission-fragments detectors and the technique of fission induced with reactor neutrons to obtain the distribution of U and Th were studied. Uranium and thorium standards evaporated on the surface of the detectors, as well as thorite and uraninite grains, were irradiated in order to measure the integrated flux of neutrons, the effective cross sections for fission with reactor neutrons for 232 Th(0,05b) and 238 U(0,30b) and to study the contribution of 238 U fission in thorium mapping. A technique for determination of uranium and thorium in minerals was studied and applied to Mica, for which were determined the contents of 4,2 ppb U e 58 ppb Th. (Author) [pt

Archaeal Diversity and CO2 Fixers in Carbonate-/Siliciclastic-Rock Groundwater Ecosystems

Directory of Open Access Journals (Sweden)

Cassandre Sara Lazar

2017-01-01

Full Text Available Groundwater environments provide habitats for diverse microbial communities, and although Archaea usually represent a minor fraction of communities, they are involved in key biogeochemical cycles. We analysed the archaeal diversity within a mixed carbonate-rock/siliciclastic-rock aquifer system, vertically from surface soils to subsurface groundwater including aquifer and aquitard rocks. Archaeal diversity was also characterized along a monitoring well transect that spanned surface land uses from forest/woodland to grassland and cropland. Sequencing of 16S rRNA genes showed that only a few surface soil-inhabiting Archaea were present in the groundwater suggesting a restricted input from the surface. Dominant groups in the groundwater belonged to the marine group I (MG-I Thaumarchaeota and the Woesearchaeota. Most of the groups detected in the aquitard and aquifer rock samples belonged to either cultured or predicted lithoautotrophs (e.g., Thaumarchaeota or Hadesarchaea. Furthermore, to target autotrophs, a series of 13CO2 stable isotope-probing experiments were conducted using filter pieces obtained after filtration of 10,000 L of groundwater to concentrate cells. These incubations identified the SAGMCG Thaumarchaeota and Bathyarchaeota as groundwater autotrophs. Overall, the results suggest that the majority of Archaea on rocks are fixing CO2, while archaeal autotrophy seems to be limited in the groundwater.

First results of U-Pb dating of metamorphic rocks of the Greater Antilles arc: age of the Mabujina complex (Cuba)

International Nuclear Information System (INIS)

Bibikova, E.V.; Somin, M.L.; Gracheva, T.V.; Makarov, V.A.; Mil'yan, G.; Shukolyukov, Yu.A.; AN SSSR, Moscow

1988-01-01

U-Pb-dating of zircons, entering the composition of metamorphic rocks of the Mabujina complex, was conducted in order to solve the problem concerming the place of metamorphic complexes in the structure and tectonic evolution of the Greater Antilles arc. The accuracy of uranium and lead determination was equal to ± 1%, the accuracy of lead isotopic ratio determination with the use of TSN-206A mass-spectrometer- ±0.15%. Isotope data showed, that all examined zircons crystallized about 100 mil. years ago

A non-Linear transport model for determining shale rock characteristics

Science.gov (United States)

Ali, Iftikhar; Malik, Nadeem

2016-04-01

Unconventional hydrocarbon reservoirs consist of tight porous rocks which are characterised by nano-scale size porous networks with ultra-low permeability [1,2]. Transport of gas through them is not well understood at the present time, and realistic transport models are needed in order to determine rock properties and for estimating future gas pressure distribution in the reservoirs. Here, we consider a recently developed non-linear gas transport equation [3], ∂p-+ U ∂p- = D ∂2p-, t > 0, (1) ∂t ∂x ∂x2 complimented with suitable initial and boundary conditions, in order to determine shale rock properties such as the permeability K, the porosity φ and the tortuosity, τ. In our new model, the apparent convection velocity, U = U(p,px), and the apparent diffusivity D = D(p), are both highly non-linear functions of the pressure. The model incorporate various flow regimes (slip, surface diffusion, transition, continuum) based upon the Knudsen number Kn, and also includes Forchchiemers turbulence correction terms. In application, the model parameters and associated compressibility factors are fully pressure dependent, giving the model more realism than previous models. See [4]. Rock properties are determined by solving an inverse problem, with model parameters adjustment to minimise the error between the model simulation and available data. It is has been found that the proposed model performs better than previous models. Results and details of the model will be presented at the conference. Corresponding author: namalik@kfupm.edu.sa and nadeem_malik@cantab.net References [1] Cui, X., Bustin, A.M. and Bustin, R., "Measurements of gas permeability and diffusivity of tight reservoir rocks: different approaches and their applications", Geofluids 9, 208-223 (2009). [2] Chiba R., Fomin S., Chugunov V., Niibori Y. and Hashida T., "Numerical Simulation of Non Fickian Diffusion and Advection in a Fractured Porous Aquifer", AIP Conference Proceedings 898, 75 (2007

Fluid and rock interaction in permeable volcanic rock

International Nuclear Information System (INIS)

Lindley, J.I.

1985-01-01

Four types of interrelated changes -geochemical, mineralogic, isotopic, and physical - occur in Oligocene volcanic units of the Mogollon-Datil volcanic field, New Mexico. These changes resulted from the operation of a geothermal system that, through fluid-rock interaction, affected 5 rhyolite ash-flow tuffs and an intercalated basaltic andesite lava flow causing a potassium metasomatism type of alteration. (1) Previous studies have shown enrichment of rocks in K 2 O as much as 130% of their original values at the expense of Na 2 O and CaO with an accompanying increase in Rb and decreases in MgO and Sr. (2) X-ray diffraction results of this study show that phenocrystic plagioclase and groundmass feldspar have been replaced with pure potassium feldspar and quartz in altered rock. Phenocrystic potassium feldspar, biotite, and quartz are unaffected. Pyroxene in basaltic andesite is replaced by iron oxide. (3) delta 18 O increases for rhyolitic units from values of 8-10 permil, typical of unaltered rock, to 13-15 permil, typical of altered rock. Basaltic andesite, however, shows opposite behavior with a delta 18 of 9 permil in unaltered rock and 6 permit in altered. (4) Alteration results in a density decrease. SEM revealed that replacement of plagioclase by fine-grained quartz and potassium feldspar is not a volume for volume replacement. Secondary porosity is created in the volcanics by the chaotic arrangement of secondary crystals

Industrial PM2.5 cause pulmonary adverse effect through RhoA/ROCK pathway.

Science.gov (United States)

Yan, Junyan; Lai, Chia-Hsiang; Lung, Shih-Chun Candice; Chen, Chongjun; Wang, Wen-Cheng; Huang, Pin-I; Lin, Chia-Hua

2017-12-01

According to the Chinese Ministry of Health, industrial pollution-induced health impacts have been the leading cause of death in China. While industrial fine particulate matter (PM 2.5 ) is associated with adverse health effects, the major action mechanisms of different compositions of PM 2.5 are currently unclear. In this study, we treated normal human lung epithelial BEAS-2B cells with industrial organic and water-soluble PM 2.5 extracts under daily alveolar deposition dose to elucidate the molecular mechanisms underlying adverse pulmonary effects induced by PM 2.5 , including oxidative damage, inflammatory response, lung epithelial barrier dysfunction, and the recruitment of macrophages. We found that water-soluble PM 2.5 extracts caused more severe cytotoxic effects on BEAS-2B cells compared with that of organic extracts. Both organic and water-soluble PM 2.5 extracts induced activation of the RhoA/ROCK pathway. Inflammatory response, epithelial barrier dysfunction, and the activation of NF-кB caused by both PM 2.5 extracts were attenuated by ROCK inhibitor Y-27632. This indicated that both PM 2.5 extracts could cause damage to epithelial cells through RhoA/ROCK-dependent NF-кB activation. Furthermore, the upregulation of macrophage adhesion induced by both PM 2.5 extracts was also attenuated by Y-27632 in a co-culture model of macrophages and the epithelial cells. Therefore, our results support that industrial PM 2.5 extracts-induced activation of the RhoA/ROCK-dependent NF-кB pathway induces pulmonary adverse effect. Thus, pharmacological inhibition of ROCK activation might have therapeutic potential in preventing lung disease associated with PM 2.5 . Copyright © 2017 Elsevier B.V. All rights reserved.

Absolute M1 and E2 Transition Probabilities in 2{sup 33}U

Energy Technology Data Exchange (ETDEWEB)

Malmskog, S G; Hoejeberg, M

1967-08-15

Using the delayed coincidence technique, the following half lives have been determined for different excited states in {sup 233}U: T{sub 1/2} (311.9 keV level) = (1.20 {+-} 0.15) x 10{sup -10} sec, T{sub 1/2} (340.5 keV level) = (5.2 {+-} 1.0) x 10{sup -11} sec, T{sub 1/2} (398.6 keV level) = (5.5 {+-} 2.0) x 10{sup -11} sec and T{sub 1/2} (415.8 keV level) < 3 x 10{sup -11}sec. From these half life determinations, together with earlier known electron intensities and conversion coefficients, 22 reduced B(Ml) and B(E2) transition probabilities (including 9 limits) have been deduced. The rotational transitions give information on the parameters {delta} and (g{sub K} - g{sub R}) . The experimental M1 and E2 transition rates between members of different bands have been analysed in terms of the predictions of the Nilsson model, taking also pairing correlations and Coriolis coupling effects into account.

Dating of pre-exposure times of lunar rocks and soils

International Nuclear Information System (INIS)

Eugster, O.

1986-01-01

Xenon produced by fission of uranium, thorium and plutonium has repeatedly been observed in lunar rocks and soils. In two basaltic rocks and in two soils Xe was found originating from fission of U-235 induced by neutrons which are due to the interactions of cosmic ray particles with lunar matter. Two facts lead to this conclusion: (1) fission Xe is present in excess of that expected for the U, Th, and Pu concentrations and for the gas retention age of the samples; and (2) the Xe-134/Xe-136 ratio of excess fission Xe is close to 1.25 as expected for neutron induced fission of U-235. Information on the duration of the exposure to cosmic rays was obtained from the Kr-81-Kr systematics whereas the effective shielding conditions were derived from the depth sensitive cosmogenic ratio Xe-131/Xe-126. For the four samples the exposure to cosmic rays in the lunar regolith is described by a two stage exposure model. The history of the four samples was derived in terms of duration and shielding depth of the two stages

Investigation on natural radioactive nuclide contents of rock products in Xi'an construction materials market

International Nuclear Information System (INIS)

Zhou Chunlin; Han Feng; Shang Aiguo; Li Tiantuo; Guo Huiping; Yie Lichao; Li Guifang

2001-01-01

The author reports the investigation results on natural radioactive nuclide contents of rock products from Xi'an construction materials market. The products were classified according to the national standard. The results show that natural radioactive nuclide contents in sampled rock products are in normal radioactive background levels. The radio-activity ranges of 238 U, 226 Ra, 232 Th and 40 K are 2.7 - 181.8, 0.92 - 271.0, 0.63 - 148.0, 1.8 - 1245 Bq·kg -1 , respectively. According to the national standard (JC 518-93), the application of some rock products must be limited

BAND ALIGNMENT OF ULTRATHIN GIZO/SiO2/Si HETEROSTRUCTURE DETERMINED BY ELECTRON SPECTROSCOPY

Directory of Open Access Journals (Sweden)

Hee Jae Kang2

2011-11-01

Full Text Available Amorphous GaInZnO (GIZO thin films are grown on SiO2/Si substrate by the RF magnetron sputtering method. By thecombination of measured band gaps from reflection energy loss spectroscopy (REELS spectra and valence band fromX-ray photo-electron spectroscopy (XPS spectra, we have demonstrated the energy band alignment of GIZO thin films.The band gap values are 3.2 eV, 3.2 eV, 3.4eV and 3.6eV for the concentration ratios of Ga: In: Zn in GIZO thin filmsare 1:1:1, 2:2:1, 3:2:1 and 4:2:1, respectively. These are attributed to the larger band gap energy of Ga2O3 comparedwith In2O3 and ZnO. The valence band offsets (ΔEv decrease from 2.18 to 1.68 eV with increasing amount of Ga inGIZO thin films for GIZO1 to GIZO4, respectively. These experimental values of band gap and valence band offsetwill provide the further understanding in the fundamental properties of GIZO/SiO2/Si heterostructure, which will beuseful in the design, modeling and analysis of the performance devices applications.

Fluid inclusion and oxygen-isotope evidence for low-temperature Au-Pt-Pd (± U) mineralization at Corronation Hill, NT

International Nuclear Information System (INIS)

Mernagh, T.

1992-01-01

The fluid inclusion and isotope data have been used to constrain the ore genesis models for the Au-Pt-Pd-U mineralization at Coronation Hill. The fluid inclusions demonstrate that the ore fluid was strongly saline with an unusually high CaCl 2 content, and that the mineralisation was probably formed from a boiling fluid at around 140 deg C. Furthermore, the fluids were highly oxidised and the replacement of earlier chlorite by hematite is common throughout the deposit. It is concluded that both U-rich and U-poor Au-Pt-Pd mineralisation were formed by descending, low-temperature, highly oxidised, very saline, meteoric fluids. The segregation of U was controlled by fluid-rock interaction in the feldspathic or carbonate rocks. Interaction with carbonaceous or chloritic rocks resulted in a reduction in fO 2 , and consequent precipitation of U, Au, Pt and Pd. The other two types of metal associations can be explained by further reaction of the mineralizing fluids. 3 figs

Assessment Rocks? The Assessment of Group Composing for Qualification

Science.gov (United States)

Thorpe, Vicki

2012-01-01

Ensembles such as rock and pop bands are places of exciting creativity and intense, enjoyable music making for young people. A recent review of New Zealand's secondary school qualification, the National Certificates of Educational Achievement (NCEA), has resulted in a new composition assessment of individuals' achievement in groups. An analysis of…

Natural {gamma}-radiation of rocks and soils from Vulcano (Aeolian Islands, Mediteranean Sea)

Energy Technology Data Exchange (ETDEWEB)

Brai, M. [Palermo Univ. (Italy). Ist. della Biocomunicazione; Hauser, S.; Bellia, S. [Palermo Univ. (Italy). Ist. di Mineralogia, Petrografia e Geochimica; Puccio, P.; Rizzo, S. [Palermo Univ. (Italy). Dipt. di Ingegneria Nucleare

1995-04-01

Gamma-ray spectra of the main lithotypes and soils from Vulcano island (Mediterranean Sea) have been carried out in order to quantify the natural radioactivity. The {sup 238}U, {sup 232}Th, and {sup 40}K contents obtained are in agreement with the genesis of the rock formation. In fact, basaltic rocks showed the lowest content of radionuclides whereas the rhyolitic rocks showed the highest concentrations. The results are comparable with other volcanic areas of southern Italy. Measurements of absorbed dose in air by TL dosimeters were also performed. The values ranged between 0.5 and 2.0 mGy y{sup -1}. Comparison between these values and those computed from {gamma}-ray spectra showed a good correlation. (author).

Natural γ-radiation of rocks and soils from Vulcano (Aeolian Islands, Mediteranean Sea)

International Nuclear Information System (INIS)

Brai, M.; Hauser, S.; Bellia, S.; Puccio, P.; Rizzo, S.

1995-01-01

Gamma-ray spectra of the main lithotypes and soils from Vulcano island (Mediterranean Sea) have been carried out in order to quantify the natural radioactivity. The 238 U, 232 Th, and 40 K contents obtained are in agreement with the genesis of the rock formation. In fact, basaltic rocks showed the lowest content of radionuclides whereas the rhyolitic rocks showed the highest concentrations. The results are comparable with other volcanic areas of southern Italy. Measurements of absorbed dose in air by TL dosimeters were also performed. The values ranged between 0.5 and 2.0 mGy y -1 . Comparison between these values and those computed from γ-ray spectra showed a good correlation. (author)

Hot dry rock geothermal energy: status of exploration and assessment. Report No. 1 of the hot dry rock assessment panel

Energy Technology Data Exchange (ETDEWEB)

1977-06-01

The status of knowledge of attempts to utilize hot dry rock (HDR) geothermal energy is summarized. It contains (1) descriptions or case histories of the ERDA-funded projects at Marysville, MT, Fenton Hill, NM, and Coso Hot Springs, CA; (2) a review of the status of existing techniques available for exploration and delineation of HDR; (3) descriptions of other potential HDR sites; (4) definitions of the probable types of HDR resource localities; and (5) an estimate of the magnitude of the HDR resource base in the conterminous United States. The scope is limited to that part of HDR resource assessment related to the determination of the extent and character of HDR, with emphasis on the igneous-related type. It is estimated that approximately 74 Q (1 Q = 1,000 Quads) of heat is stored in these sites within the conterminous U.S. at depths less than 10 km and temperatures above 150/sup 0/C, the minimum for power generation. (Q = 10/sup 18/ BTU = 10/sup 21/J; the total U.S. consumption for 1972 was approximately 0.07 Q). Approximately 6300 Q are stored in the conduction-dominated parts of the crust in the western U.S. (23% of the total surface area), again at depths less than 10 km and temperatures above 150/sup 0/C. Nearly 10,000 Q are believed to be contained in crustal rocks underlying the entire conterminous U.S., at temperatures above 150/sup 0/C. The resource base is significantly larger for lower grade heat. (JGB)

Optical band-edge absorption of oxide compound SnO2

International Nuclear Information System (INIS)

Roman, L.S.; Valaski, R.; Canestraro, C.D.; Magalhaes, E.C.S.; Persson, C.; Ahuja, R.; Silva, E.F. da; Pepe, I.; Silva, A. Ferreira da

2006-01-01

Tin oxide (SnO 2 ) is an important oxide for efficient dielectrics, catalysis, sensor devices, electrodes and transparent conducting coating oxide technologies. SnO 2 thin film is widely used in glass applications due to its low infra-red heat emissivity. In this work, the SnO 2 electronic band-edge structure and optical properties are studied employing a first-principle and fully relativistic full-potential linearized augmented plane wave (FPLAPW) method within the local density approximation (LDA). The optical band-edge absorption α(ω) of intrinsic SnO 2 is investigated experimentally by transmission spectroscopy measurements and their roughness in the light of the atomic force microscopy (AFM) measurements. The sample films were prepared by spray pyrolysis deposition method onto glass substrate considering different thickness layers. We found for SnO 2 qualitatively good agreement of the calculated optical band-gap energy as well as the optical absorption with the experimental results

Mineralogical controls on porosity and water chemistry during O_2-SO_2-CO_2 reaction of CO_2 storage reservoir and cap-rock core

International Nuclear Information System (INIS)

Pearce, Julie K.; Golab, Alexandra; Dawson, Grant K.W.; Knuefing, Lydia; Goodwin, Carley; Golding, Suzanne D.

2016-01-01

Reservoir and cap-rock core samples with variable lithology's representative of siliciclastic reservoirs used for CO_2 storage have been characterized and reacted at reservoir conditions with an impure CO_2 stream and low salinity brine. Cores from a target CO_2 storage site in Queensland, Australia were tested. Mineralogical controls on the resulting changes to porosity and water chemistry have been identified. The tested siliciclastic reservoir core samples can be grouped generally into three responses to impure CO_2-brine reaction, dependent on mineralogy. The mineralogically clean quartzose reservoir cores had high porosities, with negligible change after reaction, in resolvable porosity or mineralogy, calculated using X-ray micro computed tomography and QEMSCAN. However, strong brine acidification and a high concentration of dissolved sulphate were generated in experiments owing to minimal mineral buffering. Also, the movement of kaolin has the potential to block pore throats and reduce permeability. The reaction of the impure CO_2-brine with calcite-cemented cap-rock core samples caused the largest porosity changes after reaction through calcite dissolution; to the extent that one sample developed a connection of open pores that extended into the core sub-plug. This has the potential to both favor injectivity but also affect CO_2 migration. The dissolution of calcite caused the buffering of acidity resulting in no significant observable silicate dissolution. Clay-rich cap-rock core samples with minor amounts of carbonate minerals had only small changes after reaction. Created porosity appeared mainly disconnected. Changes were instead associated with decreases in density from Fe-leaching of chlorite or dissolution of minor amounts of carbonates and plagioclase. The interbedded sandstone and shale core also developed increased porosity parallel to bedding through dissolution of carbonates and reactive silicates in the sandy layers. Tight interbedded cap-rocks

77 FR 50916 - Safety Zone; Boston Harbor's Rock Removal Project, Boston Inner Harbor, Boston, MA

Science.gov (United States)

2012-08-23

... operation on the navigable waters of Boston Inner Harbor, in the main ship channel near Castle Island. This... operations in support of the U.S. Army Corps of Engineers rock removal project. Entering into, transiting... before the start date of the project. The U.S. Army Corps of Engineers also discussed the rock removal...

Determination of band offsets at GaN/single-layer MoS2 heterojunction

KAUST Repository

Tangi, Malleswararao

2016-07-25

We report the band alignment parameters of the GaN/single-layer (SL) MoS2 heterostructure where the GaN thin layer is grown by molecular beam epitaxy on CVD deposited SL-MoS2/c-sapphire. We confirm that the MoS2 is an SL by measuring the separation and position of room temperature micro-Raman E1 2g and A1 g modes, absorbance, and micro-photoluminescence bandgap studies. This is in good agreement with HRTEM cross-sectional analysis. The determination of band offset parameters at the GaN/SL-MoS2 heterojunction is carried out by high-resolution X-ray photoelectron spectroscopy accompanying with electronic bandgap values of SL-MoS2 and GaN. The valence band and conduction band offset values are, respectively, measured to be 1.86 ± 0.08 and 0.56 ± 0.1 eV with type II band alignment. The determination of these unprecedented band offset parameters opens up a way to integrate 3D group III nitride materials with 2D transition metal dichalcogenide layers for designing and modeling of their heterojunction based electronic and photonic devices.

Determination of band offsets at GaN/single-layer MoS2 heterojunction

KAUST Repository

Tangi, Malleswararao; Mishra, Pawan; Ng, Tien Khee; Hedhili, Mohamed N.; Janjua, Bilal; Alias, Mohd Sharizal; Anjum, Dalaver H.; Tseng, Chien-Chih; Shi, Yumeng; Joyce, Hannah J.; Li, Lain-Jong; Ooi, Boon S.

2016-01-01

We report the band alignment parameters of the GaN/single-layer (SL) MoS2 heterostructure where the GaN thin layer is grown by molecular beam epitaxy on CVD deposited SL-MoS2/c-sapphire. We confirm that the MoS2 is an SL by measuring the separation and position of room temperature micro-Raman E1 2g and A1 g modes, absorbance, and micro-photoluminescence bandgap studies. This is in good agreement with HRTEM cross-sectional analysis. The determination of band offset parameters at the GaN/SL-MoS2 heterojunction is carried out by high-resolution X-ray photoelectron spectroscopy accompanying with electronic bandgap values of SL-MoS2 and GaN. The valence band and conduction band offset values are, respectively, measured to be 1.86 ± 0.08 and 0.56 ± 0.1 eV with type II band alignment. The determination of these unprecedented band offset parameters opens up a way to integrate 3D group III nitride materials with 2D transition metal dichalcogenide layers for designing and modeling of their heterojunction based electronic and photonic devices.

Rho/ROCK signaling in regulation of corneal epithelial cell cycle progression.

Science.gov (United States)

Chen, Jian; Guerriero, Emily; Lathrop, Kira; SundarRaj, Nirmala

2008-01-01

The authors' previous study showed that the expression of a Rho-associated serine/threonine kinase (ROCK) is regulated during cell cycle progression in corneal epithelial cells. The present study was conducted to determine whether and how Rho/ROCK signaling regulates cell cycle progression. Rabbit corneal epithelial cells (RCECs) in culture were arrested in the G(0) phase of the cell cycle by serum deprivation and then allowed to re-enter the cell cycle in the presence or absence of the ROCK inhibitor (Y27632) in serum-supplemented medium. The number of cells in the S phase, the relative levels of specific cyclins and CDKs and their intracellular distribution, and the relative levels of mRNAs were determined by BrdU labeling, Western blot and immunocytochemical analyses, and real-time RT-PCR, respectively. ROCK inhibition delayed the progression of G(1) to S phase and led to a decrease in the number of RCECs entering the S phase between 12 and 24 hours from 31.5% +/- 4.5% to 8.1% +/- 2.6%. During the cell cycle progression, protein and mRNA levels of cyclin-D1 and -D3 and cyclin-dependent kinases CDK4 and CDK6 were significantly lower, whereas the protein levels of the CDK inhibitor p27(Kip1) were higher in ROCK-inhibited cells. Intracellular mRNA or protein levels of cyclin-E and protein levels of CDK2 were not significantly affected, but their nuclear translocation was delayed by ROCK inhibition. ROCK signaling is involved in cell cycle progression in RCECs, possibly by upregulation of cyclin-D1 and -D3 and CDK4, -6, and -2; nuclear translocation of CDK2 and cyclin-E; and downregulation of p27(Kip1).

Rock pushing and sampling under rocks on Mars

Science.gov (United States)

Moore, H.J.; Liebes, S.; Crouch, D.S.; Clark, L.V.

1978-01-01

Viking Lander 2 acquired samples on Mars from beneath two rocks, where living organisms and organic molecules would be protected from ultraviolet radiation. Selection of rocks to be moved was based on scientific and engineering considerations, including rock size, rock shape, burial depth, and location in a sample field. Rock locations and topography were established using the computerized interactive video-stereophotogrammetric system and plotted on vertical profiles and in plan view. Sampler commands were developed and tested on Earth using a full-size lander and surface mock-up. The use of power by the sampler motor correlates with rock movements, which were by plowing, skidding, and rolling. Provenance of the samples was determined by measurements and interpretation of pictures and positions of the sampler arm. Analytical results demonstrate that the samples were, in fact, from beneath the rocks. Results from the Gas Chromatograph-Mass Spectrometer of the Molecular Analysis experiment and the Gas Exchange instrument of the Biology experiment indicate that more adsorbed(?) water occurs in samples under rocks than in samples exposed to the sun. This is consistent with terrestrial arid environments, where more moisture occurs in near-surface soil un- der rocks than in surrounding soil because the net heat flow is toward the soil beneath the rock and the rock cap inhibits evaporation. Inorganic analyses show that samples of soil from under the rocks have significantly less iron than soil exposed to the sun. The scientific significance of analyses of samples under the rocks is only partly evaluated, but some facts are clear. Detectable quantities of martian organic molecules were not found in the sample from under a rock by the Molecular Analysis experiment. The Biology experiments did not find definitive evidence for Earth-like living organisms in their sample. Significant amounts of adsorbed water may be present in the martian regolith. The response of the soil

A wideband large dynamic range and high linearity RF front-end for U-band mobile DTV

International Nuclear Information System (INIS)

Liu Rongjiang; Liu Shengyou; Guo Guiliang; Cheng Xu; Yan Yuepeng

2013-01-01

A wideband large dynamic range and high linearity U-band RF front-end for mobile DTV is introduced, and includes a noise-cancelling low-noise amplifier (LNA), an RF programmable gain amplifier (RFPGA) and a current communicating passive mixer. The noise/distortion cancelling structure and RC post-distortion compensation are employed to improve the linearity of the LNA. An RFPGA with five stages provides large dynamic range and fine gain resolution. A simple resistor voltage network in the passive mixer decreases the gate bias voltage of the mixing transistor, and optimum linearity and symmetrical mixing is obtained at the same time. The RF front-end is implemented in a 0.25 μm CMOS process. Tests show that it achieves an IIP3 (third-order intercept point) of −17 dBm, a conversion gain of 39 dB, and a noise figure of 5.8 dB. The RFPGA achieves a dynamic range of −36.2 to 23.5 dB with a resolution of 0.32 dB. (semiconductor integrated circuits)

L-band brightness temperature disaggregation for use with S-band and C-band radiometer data for WCOM

Science.gov (United States)

Yao, P.; Shi, J.; Zhao, T.; Cosh, M. H.; Bindlish, R.

2017-12-01

There are two passive microwave sensors onboard the Water Cycle Observation Mission (WCOM), which includes a synthetic aperture radiometer operating at L-S-C bands and a scanning microwave radiometer operating from C- to W-bands. It provides a unique opportunity to disaggregate L-band brightness temperature (soil moisture) with S-band C-bands radiometer data. In this study, passive-only downscaling methodologies are developed and evaluated. Based on the radiative transfer modeling, it was found that the TBs (brightness temperature) between the L-band and S-band exhibit a linear relationship, and there is an exponential relationship between L-band and C-band. We carried out the downscaling results by two methods: (1) downscaling with L-S-C band passive measurements with the same incidence angle from payload IMI; (2) downscaling with L-C band passive measurements with different incidence angle from payloads IMI and PMI. The downscaling method with L-S bands with the same incident angle was first evaluated using SMEX02 data. The RMSE are 2.69 K and 1.52 K for H and V polarization respectively. The downscaling method with L-C bands is developed with different incident angles using SMEX03 data. The RMSE are 2.97 K and 2.68 K for H and V polarization respectively. These results showed that high-resolution L-band brightness temperature and soil moisture products could be generated from the future WCOM passive-only observations.

Natural radionuclides in the rocks of the Valle del Cervo Pluton in Piedmont.

Science.gov (United States)

Sesana, Lucia; Fumagalli, Marco; Carnevale, Mauro; Polla, Giancarla; Facchini, Ugo; Colombo, Annita; Tunesi, Annalisa; De Capitani, Luisa; Rusconi, Rosella

2006-01-01

Monitoring of the gamma radiation in Valle del Cervo Pluton was performed by determining U and Th contents in the main rock types cropping out over the entire area and pertaining to the granitic complex, syenitic complex and monzonitic complex. In particular, syenitic rocks were largely used as building and ornamental materials (e.g. Sienite della Balma). All the samples are fresh and do not present joints or fractures filled with U minerals. In the crushed samples the activity of uranium varies from 346 to 764 Bq/kg. Concentration of thorium varies from 202 to 478 Bq/kg. For all the analysed rocks uranium activity is higher than thorium one. The lowest value of radioactive concentration is referred to rocks of the granitic complex. The most active rocks are syenites. The data confirm the high activities of Valle del Cervo rock types, strongly connected with high K content of the source magma (geochemical signature); on the contrary, the activity seems to be not related to the location of the samples.

Maximizing the Optical Band Gap in 2D Photonic Crystals

DEFF Research Database (Denmark)

Hougaard, Kristian G.; Sigmund, Ole

Topology optimization is used to find the 2D photonic crystal designs with the largest relative photonic band gaps. Starting points for the topology optimization are found with an exhaustive binary search on a low resolution grid.......Topology optimization is used to find the 2D photonic crystal designs with the largest relative photonic band gaps. Starting points for the topology optimization are found with an exhaustive binary search on a low resolution grid....

The hierarchically organized splitting of chromosome bands into sub-bands analyzed by multicolor banding (MCB).

Science.gov (United States)

Lehrer, H; Weise, A; Michel, S; Starke, H; Mrasek, K; Heller, A; Kuechler, A; Claussen, U; Liehr, T

2004-01-01

To clarify the nature of chromosome sub-bands in more detail, the multicolor banding (MCB) probe-set for chromosome 5 was hybridized to normal metaphase spreads of GTG band levels at approximately 850, approximately 550, approximately 400 and approximately 300. It could be observed that as the chromosomes became shorter, more of the initial 39 MCB pseudo-colors disappeared, ending with 18 MCB pseudo-colored bands at the approximately 300-band level. The hierarchically organized splitting of bands into sub-bands was analyzed by comparing the disappearance or appearance of pseudo-color bands of the four different band levels. The regions to split first are telomere-near, centromere-near and in 5q23-->q31, followed by 5p15, 5p14, and all GTG dark bands in 5q apart from 5q12 and 5q32 and finalized by sub-band building in 5p15.2, 5q21.2-->q21.3, 5q23.1 and 5q34. The direction of band splitting towards the centromere or the telomere could be assigned to each band separately. Pseudo-colors assigned to GTG-light bands were resistant to band splitting. These observations are in concordance with the recently proposed concept of chromosome region-specific protein swelling. Copyright 2003 S. Karger AG, Basel

ROCK and PRK-2 Mediate the Inhibitory Effect of Y-27632 on Polyglutamine Aggregation

Science.gov (United States)

Shao, Jieya; Welch, William J.; Diamond, Marc I.

2009-01-01

Polyglutamine expansion in huntingtin (Htt) and the androgen receptor (AR) causes untreatable neurodegenerative diseases. Y-27632, a therapeutic lead, reduces Htt and AR aggregation in cultured cells, and Htt-induced neurodegeneration in Drosophila. Y-27632 inhibits both Rho-associated kinases ROCK and PRK-2, making its precise intracellular target uncertain. Over-expression of either kinase increases Htt and AR aggregation. Three ROCK inhibitors (Y-27632, H-1077, HA-1152), and a specific ROCK inhibitory peptide reduce polyglutamine protein aggregation, as does knockdown of ROCK or PRK-2 by RNAi. RNAi also indicates that each kinase is required for the inhibitory effects of Y-27632 to manifest fully. These two actin regulatory kinases are thus involved in polyglutamine aggregation, and their simultaneous inhibition may be an important therapeutic goal. PMID:18423405

First high resolution analysis of the 3ν2 and 3ν2 -ν2 bands of 32S16O2

Science.gov (United States)

Ulenikov, O. N.; Bekhtereva, E. S.; Gromova, O. V.; Berezkin, K. B.; Horneman, V.-M.; Sydow, C.; Maul, C.; Bauerecker, S.

2017-11-01

The second bending overtone band 3ν2 of sulfur dioxide has been studied for the first time with high resolution rotation-vibration spectroscopy. The 1530 transitions involving 728 upper state energy levels with Jmax.= 53 and Kamax . = 15 have been assigned to the 3ν2 band. The 746 transitions belonging to the 3ν2 -ν2 "hot" band have been also assigned in the region of 950-1100 cm-1. For the analysis of the assigned transitions, an effective Hamiltonian of an isolated (030) vibrational state (the Watson operator in A-reduction and Ir representation) was used. Set of 9 varied parameters was determined which reproduce the initial experimental data with the drms deviations of 9.0 ×10-4 cm-1 and 9.8 ×10-4 cm-1 for the 3ν2 and 3ν2 -ν2 bands, which are comparable with the experimental uncertainties.

Isotopic geochronology of granitic rocks from the Central Iberian Zone: comparison of methodologies

Energy Technology Data Exchange (ETDEWEB)

Antunes, I. M. H. R.; Neiva, A. M. R.; Silva, M. M. V. G.

2010-07-01

Five granitic rocks, concentrically disposed from core to rim, were distinguished in the Castelo Branco pluton. U-Pb-Th electron microprobe monazite ages from granitic rocks are similar and ranging between 297-303 Ma. The granitic rocks from Castelo Branco pluton are 310 {+-} 1 Ma old, obtained by U-Pb (ID-TIMS) in separated zircon and monazite crystals, indicating a similar emplacement age for all granitic rocks of the pluton. Initial {sup 8}7Sr/{sup 8}6Sr isotopic ratios and {epsilon}Nd{sub 3}10 and {delta}{sup 1}8O values suggest three distinct pulses of granitic magma and that they are derived from partial melting of heterogeneous metasedimentary materials. The other granitic rocks are related by magmatic differentiation and show small variations in ({sup 8}7Sr/{sup 8}6Sr)310, {epsilon}Nd{sub 3}10 and {delta}{sup 1}8O. The granitic pluton of Castelo Branco shows a rare reverse zoning. (Author) 12 refs.

Technique for estimating the sound power level radiated by pneumatic rock drills and the evaluation of a CSIR prototype rock drill with engineering noise controls

CSIR Research Space (South Africa)

Kovalchik, PG

2009-05-01

Full Text Available and the radiation patterns in octave and 1/3 octave bands. Overall sound power level is also determined. This paper also reports the results obtained by using this procedure to evaluate a SECO S215 standard production drill and a CSIR Miningtek prototype rock drill...

Radioisotope distribution characteristics of the groundwater system in volcanic-type U deposits and isotope-dating estimation of the system

International Nuclear Information System (INIS)

Zhou Bingguan

1988-01-01

On the basis of groundwater sample measurements collected from the uranogenic belt of Mesozoic volcanic rocks in East China, the distribution characteristics of radioisotopes, including the total U content (CΣu), the activity of nuclides (Aui) or their activity ratio (ARu) and the relationship among the three ((Aui,ARu)=f(CΣu)), have been studied. Also, it is performed for radioactive water halos in the area to be divided into four various mineralization tendencies: (1) the convergent tendency of negative correlation, which has the genetic relationship with the primary U accumulation in volcanic rocks; (2) the scattered tendency of positive correlation, which is intimately related to epigenetic U mineralization in the supergene zone of volcanic rocks or in the sandstones; (3) the both positive and negative multiple-correlative tendency, which indicates that the primary volcanic-type U deposit has been leached and destroyed, and the secondary U enrichment has occurred within the supergene zone; (4) non-correlative tendency, which mainly results from increasing dispersion U. For the above recognitions, an evolution model for radioactive water halos related to this type of U deposit has been derived, and an attempt to estimate the radioisotopic age of the groundwater system also has been made. (author). 14 refs, 9 figs, 2 tabs

Spin dependence of intra-ground-state-band E2 transitions in the SU(3) limit of the sdg interacting boson model

Science.gov (United States)

Long, G. L.; Ji, H. Y.

1998-04-01

B(E2, L+2-->L) transitions in the sdg interacting boson model SU(3) limit are studied with a general E2 transition operator. Analytical expressions are obtained using a group theoretic method. It is found that when using transition operators of the form (d†g~+g†d~)2 or (g†g~)2, the B(E2, L+2-->L) values in the ground-state band have an L(L+3) dependent term. As L increases, the B(E2) values can be larger than the rigid rotor model value. Application to 236,238U is discussed.

Basic rocks in Finland

International Nuclear Information System (INIS)

Piirainen, T.; Gehoer, S.; Iljina, M.; Kaerki, A.; Paakkola, J.; Vuollo, J.

1992-10-01

Basic igneous rocks, containing less than 52% SiO 2 , constitute an important part of the Finnish Archaean and Proterozoic crust. In the Archaean crust exist two units which contain the majority of the basic rocks. The Arcaean basic rocks are metavolcanics and situated in the Greenstone Belts of Eastern Finland. They are divided into two units. The greenstones of the lower one are tholeiites, komatiites and basaltic komatiites. The upper consists of bimodal series of volcanics and the basic rocks of which are Fe-tholeiites, basaltic komatiites and komatiites. Proterozoic basic rocks are divided into seven groups according to their ages. The Proterozoic igneous activity started by the volominous basic magmatism 2.44 Ga ago. During this stage formed the layered intrusions and related dykes in the Northern Finland. 2.2 Ga old basic rocks are situated at the margins of Karelian formations. 2.1 Ga aged Fe-tholeiitic magmatic activity is widespread in Eastern and Northern Finland. The basic rocks of 1.97 Ga age group are met within the Karelian Schist Belts as obducted ophiolite complexes but they occur also as tholeiitic diabase dykes cutting the Karelian schists and Archean basement. The intrusions and the volcanics of the 1.9 Ga old basic igneous activity are mostly encountered around the Granitoid Complex of Central Finland. Subjotnian, 1.6 Ga aged tholeiitic diabases are situated around the Rapakivi massifs of Southern Finland, and postjotnian, 1.2 Ga diabases in Western Finland where they form dykes cutting Svecofennian rocks

The Usability of Rock-Like Materials for Numerical Studies on Rocks

Science.gov (United States)

Zengin, Enes; Abiddin Erguler, Zeynal

2017-04-01

The approaches of synthetic rock material and mass are widely used by many researchers for understanding the failure behavior of different rocks. In order to model the failure behavior of rock material, researchers take advantageous of different techniques and software. But, the majority of all these instruments are based on distinct element method (DEM). For modeling the failure behavior of rocks, and so to create a fundamental synthetic rock material model, it is required to perform related laboratory experiments for providing strength parameters. In modelling studies, model calibration processes are performed by using parameters of intact rocks such as porosity, grain size, modulus of elasticity and Poisson ratio. In some cases, it can be difficult or even impossible to acquire representative rock samples for laboratory experiments from heavily jointed rock masses and vuggy rocks. Considering this limitation, in this study, it was aimed to investigate the applicability of rock-like material (e.g. concrete) to understand and model the failure behavior of rock materials having complex inherent structures. For this purpose, concrete samples having a mixture of %65 cement dust and %35 water were utilized. Accordingly, intact concrete samples representing rocks were prepared in laboratory conditions and their physical properties such as porosity, pore size and density etc. were determined. In addition, to acquire the mechanical parameters of concrete samples, uniaxial compressive strength (UCS) tests were also performed by simultaneously measuring strain during testing. The measured physical and mechanical properties of these extracted concrete samples were used to create synthetic material and then uniaxial compressive tests were modeled and performed by using two dimensional discontinuum program known as Particle Flow Code (PFC2D). After modeling studies in PFC2D, approximately similar failure mechanism and testing results were achieved from both experimental and

Band structure and orbital character of monolayer MoS2 with eleven-band tight-binding model

Science.gov (United States)

Shahriari, Majid; Ghalambor Dezfuli, Abdolmohammad; Sabaeian, Mohammad

2018-02-01

In this paper, based on a tight-binding (TB) model, first we present the calculations of eigenvalues as band structure and then present the eigenvectors as probability amplitude for finding electron in atomic orbitals for monolayer MoS2 in the first Brillouin zone. In these calculations we are considering hopping processes between the nearest-neighbor Mo-S, the next nearest-neighbor in-plan Mo-Mo, and the next nearest-neighbor in-plan and out-of-plan S-S atoms in a three-atom based unit cell of two-dimensional rhombic MoS2. The hopping integrals have been solved in terms of Slater-Koster and crystal field parameters. These parameters are calculated by comparing TB model with the density function theory (DFT) in the high-symmetry k-points (i.e. the K- and Γ-points). In our TB model all the 4d Mo orbitals and the 3p S orbitals are considered and detailed analysis of the orbital character of each energy level at the main high-symmetry points of the Brillouin zone is described. In comparison with DFT calculations, our results of TB model show a very good agreement for bands near the Fermi level. However for other bands which are far from the Fermi level, some discrepancies between our TB model and DFT calculations are observed. Upon the accuracy of Slater-Koster and crystal field parameters, on the contrary of DFT, our model provide enough accuracy to calculate all allowed transitions between energy bands that are very crucial for investigating the linear and nonlinear optical properties of monolayer MoS2.

A comparison of fossilized dinosaur bone and the surrounding rock using PIXE analysis

International Nuclear Information System (INIS)

Neilsen, D.W.; Rees, L.B.; Mangelson, N.F.; Hill, M.W.

1992-01-01

Six samples of fossilized dinosaur bone and surrounding rock were analyzed by PIXE to investigate general relations between the bone and rock. The powdered samples were brought into an acid solution by a lithium metaborate fusion process. The data were analyzed with chemometric methods to successfully differentiate the bone samples from the complementary rock samples. The Sr/Ca ratio is consistently higher in fossilized bone than the surrounding rock. Ba, Y and U, when found in the rock, appear in significantly higher concentrations in the bone. S and Ti, elements commonly found in rock samples, are not found in the bone samples. (author)

Big Bang Day : Physics Rocks

CERN Multimedia

Brian Cox; John Barrowman; Eddie Izzard

2008-01-01

Is particle physics the new rock 'n' roll? The fundamental questions about the nature of the universe that particle physics hopes to answer have attracted the attention of some very high profile and unusual fans. Alan Alda, Ben Miller, Eddie Izzard, Dara O'Briain and John Barrowman all have interests in this branch of physics. Brian Cox - CERN physicist, and former member of 90's band D:Ream, tracks down some very well known celebrity enthusiasts and takes a light-hearted look at why this subject can appeal to all of us.

Synthesis, band structure, and optical properties of Ba2ZnV2O8

International Nuclear Information System (INIS)

Chen, D.-G.; Cheng, W.-D.; Wu, D.-S.; Zhang, H.; Zhang, Y.-C.; Gong, Y.-J.; Kan, Z.-G.

2004-01-01

A novel compound Ba 2 ZnV 2 O 8 has been synthesized in high temperature solution reaction and its crystal structure has been characterized by means of single crystal X-ray diffraction analysis. It crystallizes in monoclinic system and belongs to space group P2 1 /c with a=7.9050(16), b=16.149(3), c=6.1580(12)A, β=90.49(3). It builds up from 1-D branchy chains of [ZnV 2 O 8 4- ] ∞ , and the Ba 2+ cations are located in the space among these chains. The IR spectrum, ultraviolet-visible diffuse reflection integral spectrum and fluorescent spectra of this compound have been investigated. The calculated results of energy band structure by the density functional theory method show that the solid-state compound of Ba 2 ZnV 2 O 8 is an insulator with direct band gap of 3.48eV. The calculated total and partial density of states indicate that the top valence bands are contributions from the mixings of O-2p, V-3d, and Zn-3d states and low conduction bands mostly originate from unoccupied antibonding states between the V-3d and O-2p states. The V-O bonds are mostly covalence characters and Zn-O bonds are mostly ionic interactions, and the ionic interaction strength is stronger between the Ba-O than between the Zn-O. The refractive index of n x , n y , and n z is estimated to be 1.7453, 1.7469, and 1.7126, respectively, at wavelength of 1060nm for Ba 2 ZnV 2 O 8 crystal

The selectivity and promiscuity of brain-neuroregenerative inhibitors between ROCK1 and ROCK2 isoforms: An integration of SB-QSSR modelling, QM/MM analysis and in vitro kinase assay.

Science.gov (United States)

Zhu, L; Yang, Y; Lu, X

2016-01-01

The Rho-associated kinases (ROCKs) have long been recognized as an attractive therapeutic target for various neurological diseases; selective inhibition of ROCK1 and ROCK2 isoforms would result in distinct biological effects on neurogenesis, neuroplasticity and neuroregeneration after brain surgery and traumatic brain injury. However, the discovery and design of isoform-selective inhibitors remain a great challenge due to the high conservation and similarity between the kinase domains of ROCK1 and ROCK2. Here, a structure-based quantitative structure-selectivity relationship (SB-QSSR) approach was used to correlate experimentally measured selectivity with the difference in inhibitor binding to the two kinase isoforms. The resulting regression models were examined rigorously through both internal cross-validation and external blind validation; a nonlinear predictor was found to have high fitting stability and strong generalization ability, which was then employed to perform virtual screening against a structurally diverse, drug-like compound library. Consequently, five and seven hits were identified as promising candidates of 1-o-2 and 2-o-1 selective inhibitors, respectively, from which seven purchasable compounds were tested in vitro using a standard kinase assay protocol to determine their inhibitory activity against and selectivity between ROCK1 and ROCK2. The structural basis, energetic property and biological implication underlying inhibitor selectivity and promiscuity were also investigated systematically using a hybrid quantum mechanics/molecular mechanics (QM/MM) scheme.

Regional analysis of tertiary volcanic Calderas (western U.S.) using Landsat Thematic Mapper imagery

Science.gov (United States)

Spatz, David M.; Taranik, James V.

1989-01-01

The Landsat Thematic Mapper (TM) imagery of the Basin and Range province of southern Nevada was analyzed to identify and map volcanic rock assemblages at three Tertiary calderas. It was found that the longer-wavelength visible and the NIR TM Bands 3, 5, and 7 provide more effective lithologic discrimination than the shorter-wavelength bands, due partly to deeper penetration of the longer-wavelength bands, resulting in more lithologically driven radiances. Shorter-wavelength TM Bands 1 and 2 are affected more by surficial weathering products including desert varnish which may or may not provide an indirect link to lithologic identity. Guidelines for lithologic analysis of volcanic terrains using Landsat TM imagery are outlined.

Determination of trace quantities of uranium in rocks mass spectrometric isotope dilution technique

International Nuclear Information System (INIS)

Kakazu, Mauricio Hiromitu

1980-01-01

A detailed experimental investigation on the thermionic emission of uranium deposited on a single flat type rhenium filament has been carried out. The study was aimed at determining the influence of various forms of deposition on the emission sensitivity and thermal stability of U + , UO + and UO 2 + ions. Based on these investigations, a technique, involving an addition of a small quantity of colloidal suspension of graphite on top of the uranyl nitrate sample deposited, was chosen because of its higher, emission sensitivity for uranium metal ions. The experimental parameters of the technique were optimised and the technique was employed in the determination of trace quantities of uranium in rock samples using mass spectrometric isotope dilution method. For the mass spectrometric isotope dilution analysis National Bureau of Standards uranium isotopic standard NBS-U 970 was employed as a tracer, where as the mass discrimination effect in the uranium isotope analysis was corrected using the uranium isotopic standard NBS-U500. Uranium was determined in each of the seven granite samples from Wyoming, USA and two USGS standard rocks. The precision of the analysis was found to be ±1% . The uranium values obtained on the rock samples were compared with the analyses of other investigators. Influence of the sample splitting on the uranium analysis was discussed in the light of the analytical results obtained.(author)

Numerical Study on CO2-Brine-Rock Interaction of Enhanced Geothermal Systems with CO2 as Heat Transmission Fluid

Directory of Open Access Journals (Sweden)

Wan Yuyu

2016-01-01

Full Text Available Enhanced Geothermal Systems (EGS with CO2 instead of water as heat transmission fluid is an attractive concept for both geothermal resources development and CO2 geological sequestration. Previous studies show that CO2 has lots of favorable properties as heat transmission fluid and also can offer geologic storage of CO2 as an ancillary benefit. However, after CO2 injection into geological formations, chemical reaction between brine and rock can change chemical characteristics of saline and properties of rock such as porosity and permeability. Is this advantage or disadvantage for EGS operating? To answer this question, we have performed chemically reactive transport modeling to investigate fluid-rock interactions and CO2 mineral carbonation of Enhanced Geothermal Systems (EGS site at Desert Peak (Nevada operated with CO2. The simulation results show that (1 injection CO2 can create a core zone fulfilled with CO2 as main working domain for EGS, and (2 CO2 storage can induced self-enhancing alteration of EGS.

Rock Tea extract (Jasonia glutinosa) relaxes rat aortic smooth muscle by inhibition of L-type Ca(2+) channels.

Science.gov (United States)

Valero, Marta Sofía; Oliván-Viguera, Aida; Garrido, Irene; Langa, Elisa; Berzosa, César; López, Víctor; Gómez-Rincón, Carlota; Murillo, María Divina; Köhler, Ralf

2015-12-01

In traditional herbal medicine, Rock Tea (Jasonia glutinosa) is known for its prophylactic and therapeutic value in various disorders including arterial hypertension. However, the mechanism by which Rock Tea exerts blood pressure-lowering actions has not been elucidated yet. Our aim was to demonstrate vasorelaxing effects of Rock Tea extract and to reveal its possible action mechanism. Isometric myography was conducted on high-K+-precontracted rings from rat thoracic aorta and tested extracts at concentrations of 0.5-5 mg/ml. Whole-cell patch-clamp experiments were performed in rat aortic vascular smooth muscle cells (line A7r5) to determine blocking effects on L-type Ca(2+) channels. Rock Tea extract relaxed the aorta contracted by high [K+] concentration dependently with an EC50 of ≈2.4 mg/ml and produced ≈75 % relaxation at the highest concentration tested. The L-type Ca(2+) channel blocker, verapamil (10(-6) M), had similar effects. Rock Tea extract had no effect in nominally Ca(2+)-free high-K(+) buffer but significantly inhibited contractions to re-addition of Ca(2+). Rock Tea extract inhibited the contractions induced by the L-type Ca(2+) channel activator Bay K 8644 (10(-5) M) and by phenylephrine (10(-6) M). Rock Tea extract and Y-27632 (10(-6) M), Rho-kinase inhibitor, had similar effects and the respective effects were not additive. Patch-clamp experiments demonstrated that Rock Tea extract (2.5 mg/ml) virtually abolished L-type Ca(2+) currents in A7r5. We conclude that Rock Tea extract produced vasorelaxation of rat aorta and that this relaxant effect is mediated by inhibition of L-type Ca(2+) channels. Rock Tea extracts may be of phytomedicinal value for prevention and adjuvant treatment of hypertension and other cardiovascular diseases.

Omnidirectional photonic band gap in magnetron sputtered TiO{sub 2}/SiO{sub 2} one dimensional photonic crystal

Energy Technology Data Exchange (ETDEWEB)

Jena, S., E-mail: shuvendujena9@gmail.com [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Tokas, R.B.; Sarkar, P. [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Misal, J.S.; Maidul Haque, S.; Rao, K.D. [Photonics & Nanotechnology Section, BARC-Vizag, Autonagar, Atomic & Molecular Physics Division, Bhabha Atomic Research Centre facility, Visakhapatnam 530 012 (India); Thakur, S.; Sahoo, N.K. [Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2016-01-29

One dimensional photonic crystal (1DPC) of TiO{sub 2}/SiO{sub 2} multilayer has been fabricated by sequential asymmetric bipolar pulsed dc magnetron sputtering of TiO{sub 2} and radio frequency magnetron sputtering of SiO{sub 2} to achieve wide omnidirectional photonic band in the visible region. The microstructure and optical response of the TiO{sub 2}/SiO{sub 2} photonic crystal have been characterized by atomic force microscopy, scanning electron microscopy and spectrophotometry respectively. The surface of the photonic crystal is very smooth having surface roughness of 2.6 nm. Reflection and transmission spectra have been measured in the wavelength range 300 to 1000 nm for both transverse electric and transverse magnetic waves. Wide high reflection photonic band gap (∆ λ = 245 nm) in the visible and near infrared regions (592–837 nm) at normal incidence has been achieved. The measured photonic band gap (PBG) is found well matching with the calculated photonic band gap of an infinite 1DPC. The experimentally observed omnidirectional photonic band 592–668 nm (∆ λ = 76 nm) in the visible region with band to mid-band ratio ∆ λ/λ = 12% for reflectivity R > 99% over the incident angle range of 0°–70° is found almost matching with the calculated omnidirectional PBG. The omnidirectional reflection band is found much wider as compared to the values reported in literature so far in the visible region for TiO{sub 2}/SiO{sub 2} periodic photonic crystal. - Highlights: • TiO{sub 2}/SiO{sub 2} 1DPC has been fabricated using magnetron sputtering technique. • Experimental optical response is found good agreement with simulation results. • Wide omnidirectional photonic band in the visible spectrum has been achieved.

Revegetation/rock cover for stabilization of inactive U-tailings sites

International Nuclear Information System (INIS)

Beedlow, P.A.; Cadwell, L.L.

1982-01-01

Soil placed over any sealant/barrier system can provide a protective mantle if the soil is not lost by erosion. Vegetation is an attractive choice for controlling erosion because it can provide an economic self-renewing cover that serves to reduce erosion by both wind and water. Vegetation alone, however, may not adequately stabilize the surface in extremely arid areas. In those areas, a properly designed surface treatment of rock cover, perhaps in conjunction with vegetation, may be necessary to stabilize the tailings surfaces. The objective of this program is to establish guidelines for surface stabilization that are compatible with sealant/barrier systems and that are suited to soils and climates at inactive uranium mill tailings sites. These guidelines will provide the means to estimate potential vegetation cover, potential erosion, effects of surface treatments on sealant/barrier systems, and costs of vegetation and rock covers. Methods for establishing vegetation on sealed tailings will also be provided

Barringerite Fe2P from Pyrometamorphic Rocks of the Hatrurim Formation, Israel

Science.gov (United States)

Britvin, S. N.; Murashko, M. N.; Vapnik, E.; Polekhovsky, Yu. S.; Krivovichev, S. V.

2017-12-01

The article provides a detailed mineralogical and crystallochemical description (including refinement of the crystal structure) of the first finding of the phosphide class mineral barringerite, Fe2P, from terrestrial pyrometamorphic rocks of the Hatrurim Formation in Israel. The mineral occurs in the association of the so-called paralavas—initially silicate—carbonate sedimentary rocks that remelted during pyrometamorphic processes at a temperature above 1000°C and at a low pressure. Questions on the genesis and crystal chemistry of barringerite are discussed in connection with another polymorphic iron phosphide, allabogdanite (Fe,Ni)2P.

Bi2Se3/CdS/TiO2 hybrid photoelectrode and its band-edge levels

International Nuclear Information System (INIS)

Zhang, Qi; Su, Jun; Zhang, Xianghui; Li, Jian; Zhang, Aiqing; Gao, Yihua

2012-01-01

Highlights: ► CVD synthesis of Bi 2 Se 3 nanoparticles. ► Bi 2 Se 3 and CdS co-sensitized TiO 2 nanorod arrays electrode was assembled by CVD. ► Direct physical contact heterojunctions were formed at the interfaces of electrode. ► Cascade structure of band-edge levels was formed in Bi 2 Se 3 /CdS/TiO 2 electrode. - Abstract: Bismuth selenide (Bi 2 Se 3 ) was chosen as the sensitizer to TiO 2 nanorod (NR) arrays photoelectrode to harvest infrared (IR) light for its narrow band gap. For utilizing more amount of IR solar energy, Bi 2 Se 3 nanoparticles (NPs) were grown up to a relative larger grain size. And, a cadmium sulfide (CdS) NPs intermediate layer was introduced to help, to coordinate, the structure of band-edge levels in Bi 2 Se 3 /CdS/TiO 2 electrode. Here, a chemical vapor deposition (CVD) strategy was introduced to assemble this kind of composite photoelectrode. And a cascade structure of band-edge levels constructed in it when achieving electrostatic equilibrium in Na 2 S/Na 2 SO 3 aqueous solution electrolyte revealed by electrochemical analysis method, which will facilitate the hydrogen generation.

Rock stars for the day

CERN Multimedia

Stefania Pandolfi

2015-01-01

After a two-year hiatus, the CERN Hardronic Festival is back! On 8 August, ten CERN MusiClub bands will take to the stage for the popular event. As usual, the non-stop show will take place on the terrace of Restaurant 3 and will run until after midnight.   The Canettes Blues Band, part of the CERN MusiClub, performing live on the Music In The Park stage at the Montreux Jazz Festival, on 18 July 2013. A large range of musical styles will entertain the audience: from Irish folk, via 70s/80s/90s rock, to pop, blues and R&B. Alongside the music there will be activities for kids and food and drink stands. This year, the income from food sales will be donated to charity. The spirit that has characterised the festival ever since the first event in 1989 is that of a staff party. Any band who volunteers to play also helps to organise the event and set up the stage. “This is a really good thing because a festival that has been growing for many years requires a considerable amount of har...

Compaction bands in shale revealed through digital volume correlation of time-resolved X-ray tomography scans

Science.gov (United States)

McBeck, J.; Kobchenko, M.; Hall, S.; Tudisco, E.; Cordonnier, B.; Renard, F.

2017-12-01

Previous studies have identified compaction bands primarily within sandstones, and in fewer instances, within other porous rocks and sediments. Using Digital Volume Correlation (DVC) of X-ray microtomography scans, we find evidence of localized zones of high axial contraction that form tabular structures sub-perpendicular to maximum compression, σ1, in Green River shale. To capture in situ strain localization throughout loading, two shale cores were deformed in the HADES triaxial deformation apparatus installed on the X-ray microtomography beamline ID19 at the European Synchrotron Radiation Facility. In these experiments, we increase σ1 in increments of two MPa, with constant confining pressure (20 MPa), until the sample fails in macroscopic shear. After each stress step, a 3D image of the sample inside the rig is acquired at a voxel resolution of 6.5 μm. The evolution of lower density regions within 3D reconstructions of linear attenuation coefficients reveal the development of fractures that fail with some opening. If a fracture produces negligible dilation, it may remain undetected in image segmentation of the reconstructions. We use the DVC software TomoWarp2 to identify undetected fractures and capture the 3D incremental displacement field between each successive pair of microtomography scans acquired in each experiment. The corresponding strain fields reveal localized bands of high axial contraction that host minimal shear strain, and thus match the kinematic definition of compaction bands. The bands develop sub-perpendicular to σ1 in the two samples in which pre-existing bedding laminations were oriented parallel and perpendicular to σ1. As the shales deform plastically toward macroscopic shear failure, the number of bands and axial contraction within the bands increase, while the spacing between the bands decreases. Compaction band development accelerates the rate of overall axial contraction, increasing the mean axial contraction throughout the sample

Kinetics of radioisotope exchange between brine and rock in a geothermal system

International Nuclear Information System (INIS)

Hammond, D.E.; Zukin, J.G.; Teh-Lung Ku

1988-01-01

A wide range of isotopes in the /sup 238/U, /sup 235/U, and /sup 232/Th decay chains was measured in geothermal brines collected from two production zones at 1898 and 3220 m in the Salton Sea Scientific Drilling Project well. High concentrations of radium, radon, and lead isotopes are generated and maintained by the input of these isotopes from solid phases into brine by both recoil and leaching processes, by the high chloride content of the brine which complexes radium and lead, and by the apparent absence of suitable unoccupied adsorption sites. In contrast, uranium, thorium, actinium, bismuth, and polonium isotopes all have low concentrations due to their efficient sorption from brine to rock. Measurements of short-lived isotopes in these decay series yield insights regarding the mechanisms controlling radioisotope exchange, and they permit estimation of rates of brine-rock interaction. For example, the /sup 228/Ac//sup 228/Ra activity ratio of 0.2 in brines indicates that the mean residence time of actinium in solution before sorption onto solid surfaces is less than 2.5 hours

Signature splitting in nuclear rotational bands: Neutron i13/2 systematics

International Nuclear Information System (INIS)

Mueller, W.F.; Jensen, H.J.; Reviol, W.; Riedinger, L.L.; Yu, C.; Zhang, J.; Nazarewicz, W.; Wyss, R.

1994-01-01

Experimental values of signature splitting in νi 13/2 rotational bands in odd-N even-Z nuclei in the Z=62--78 region are collected and presented. A procedure is introduced to calculate signature splitting within the cranked deformed Woods-Saxon model. In the theoretical treatment, deformation parameters are obtained by minimizing the total Routhians of individual νi 13/2 bands, and the procedure accounts for the possibility that the two signatures have different deformations and pairing gaps. Experimental signature splitting data for νi 13/2 bands in Dy, Er, Yb, Hf, W, and Os nuclei are compared with calculated values. The sensitivity of calculated signature splitting to changes in deformation, pairing, and other model parameters is presented

The Amazon-Laurentian connection as viewed from the Middle Proterozoic rocks in the central Andes, western Bolivia and northern Chile

Science.gov (United States)

Tosdal, R.M.

1996-01-01

Middle Proterozoic rocks underlying the Andes in western Bolivia, western Argentina, and northern Chile and Early Proterozoic rocks of the Arequipa massif in southern Peru?? from the Arequipa-Antofalla craton. These rocks are discontinuously exposed beneath Mesozoic and Cenozoic rocks, but abundant crystalline clasts in Tertiary sedimentary rocks in the western altiplano allow indirect samples of the craton. Near Berenguela, western Bolivia, the Oligocene and Miocene Mauri Formation contains boulders of granodiorite augen gneiss (1171??20 Ma and 1158??12 Ma; U-Pb zircon), quartzose gneiss and granofels that are inferred to have arkosic protoliths (1100 Ma source region; U-Pb zircon), quartzofeldspathic and mafic orthogneisses that have amphibolite- and granulite-facies metamorphic mineral assemblages (???1080 Ma metamorphism; U-Pb zircon), and undeformed granitic rocks of Phanerozoic(?) age. The Middle Proterozoic crystalline rocks from Berenguela and elsewhere in western Bolivia and from the Middle Proterozoic Bele??n Schist in northern Chile generally have present-day low 206Pb/204Pb ( 15.57), and elevated 208Pb/204Pb (37.2 to 50.7) indicative of high time-averaged Th/U values. The Middle Proterozoic rocks in general have higher presentday 206Pb/204Pb values than those of the Early Proterozoic rocks of the Arequipa massif (206Pb/204Pb between 16.1 and 17.1) but lower than rocks of the southern Arequipa-Antofalla craton (206Pb/204Pb> 18.5), a difference inferred to reflect Grenvillian granulite metamorphism. The Pb isotopic compositions for the various Proterozoic rocks lie on common Pb isotopic growth curves, implying that Pb incorporated in rocks composing the Arequipa-Antofalla craton was extracted from a similar evolving Pb isotopic reservoir. Evidently, the craton has been a coherent terrane since the Middle Proterozoic. Moreover, the Pb isotopic compositions for the Arequipa-Antofalla craton overlap those of the Amazon craton, thereby supporting a link

Band alignment studies of Al2O3/CuGaO2 and ZnO/CuGaO2 hetero-structures grown by pulsed laser deposition

International Nuclear Information System (INIS)

Ajimsha, R.S.; Das, Amit K.; Joshi, M.P.; Kukreja, L.M.

2014-01-01

Highlights: • Band offset studies at the interface of Al 2 O 3 /CuGaO 2 and ZnO/CuGaO 2 hetero-structures were performed using X-ray photoelectron spectroscopy. • Valance band offsets (VBO) of these hetero-structures were obtained from respective XPS peak positions and VB spectra using Kraut's equation. • Al 2 O 3 /CuGaO 2 interface exhibited a type I band alignment with valance band offset (VBO) of 4.05 eV whereas type II band alignment was observed in ZnO/CuGaO 2 hetero-structure with a VBO of 2.32 eV. • Schematic band alignment diagram for the interface of these hetero-structures has been constructed. • Band offset and alignment studies of these heterojunctions are important for gaining insight to the design of various optoelectronic devices based on such hetero-structures. - Abstract: We have studied the band offset and alignment of pulsed laser deposited Al 2 O 3 /CuGaO 2 and ZnO/CuGaO 2 hetero-structures using photoelectron spectroscopy. Al 2 O 3 /CuGaO 2 interface exhibited a type I band alignment with valance band offset (VBO) of 4.05 eV whereas type II band alignment was observed in ZnO/CuGaO 2 hetero-structure with a VBO of 2.32 eV. Schematic band alignment diagram for the interface of these hetero-structures has been constructed. Band offset and alignment studies of these heterojunctions are important for gaining insight to the design of various optoelectronic devices based on such hetero-structures

Emergent nanoscale fluctuations in high rock-salt PbTe

Science.gov (United States)

Billinge, Simon

2013-03-01

Lead Telluride is one of the most promising thermoelectric materials in the temperature range just above room temperature. It is a narrow band gap semiconductor with a high Seebeck coefficient and a low thermal conductivity. It is structurally much simpler than many other leading candidates for high performance thermoelectrics being a binary rock-salt, isostructural to NaCl. The thermoelectric figure of merit, ZT, can be markedly improved by alloying with various other elements by forming quenched nanostructures. The undoped endmember, PbTe, does not have any such quenched nanostructure, yet has a rather low intrinsic thermal conductivity. There are also a number of interesting and non-canonical behaviors that it exhibits, such as an increasing measured band-gap with increasing temperature, exactly opposite to what is normally seen due to Fermi smearing of the band edge, and an unexpected non-monotonicity of the band gap in the series PbTe - PbSe - PbS. The material is on the surface simple, but hides some interesting complexity. We have investigated in detail the PbTe endmember using x-ray and neutron diffraction and neutron inelastic scattering. To our surprise, using the atomic pair distribution function (PDF) analysis of neutron powder diffraction data we found that an interesting and non-trivial local structure that appears on warming. with the Pb atoms moving off the high-symmetry rock-salt positions towards neighboring Te ions. No evidence for the off-centering of the Pb atoms is seen at low temperature. The crossover from the locally undistorted to the locally distorted state occurs on warming between 100 K and 250 K. This unexpected emergence of local symmetry broken distortions from an undistorted ground-state we have called emphanisis, from the Greek for appearing from nothing. We have also investigated the lattice dynamics of the system to search for a dynamical signature of this behavior and extended the studies to doped systems and I will also

Hubbard-U band-structure methods

DEFF Research Database (Denmark)

Albers, R.C.; Christensen, Niels Egede; Svane, Axel

2009-01-01

The last decade has seen a large increase in the number of electronic-structure calculations that involve adding a Hubbard term to the local-density approximation band-structure Hamiltonian. The Hubbard term is then determined either at the mean-field level or with sophisticated many......-body techniques such as using dynamical mean-field theory. We review the physics underlying these approaches and discuss their strengths and weaknesses in terms of the larger issues of electronic structure that they involve. In particular, we argue that the common assumptions made to justify such calculations...

Design and implementation of low profile antenna for dual-band applications using rotated e-shaped conductor-backed plane.

Science.gov (United States)

Jalali, Mahdi; Sedghi, Tohid; Shafei, Shahin

2014-01-01

A novel configuration of a printed monopole antenna with a very compact size for satisfying WLAN operations at the 5.2/5.8 GHz and also for X-band operations at the 10 GHz has been proposed. The antenna includes a simple square-shaped patch as the radiator, the rotated U-shaped conductor back plane element with embedded strip on it, and the partial rectangular ground surface. By using the rotated U-shaped conductor-backed plane with proper values, good impedance matching and improvement in bandwidth can be achieved, at the lower and upper bands. The impedance bandwidth for S11 WLAN-band and 4.2 dBi at X-band. The experimental results represent that the realized antenna with good omnidirectional radiation characteristics, enough impedance bandwidth, and reasonable gains can be appropriate for various applications of the future developed technologies and handheld devices.

Precipitation and purification of uranium from rock phosphate

International Nuclear Information System (INIS)

AbowSlama, E.H.Y.; Sam, A.K.; Etemad Ebraheem

2014-01-01

This study was carried-out to leach uranium from rock phosphate using sulphuric acid in the presence of potassium chlorate as an oxidant and to investigate the relative purity of different forms of yellow cakes produced with ammonia, magnesia and sodium hydroxide as precipitants, as well as purification of the products with TBP and matching its impurity levels with specifications of the commercial products. Alpha-particle spectrometry was used for determination of activity concentration of uranium isotopes in rock phosphate, resulting phosphoric acid, and in different forms of the yellow cake. Likewise, atomic absorption spectroscopy was used for determination of impurities. On the average, the equivalent mass concentration of uranium was 119.38 ± 79.66 ppm (rock phosphate) and 57.85 ± 20.46 ppm (phosphoric acid) with corresponding low percent of dissolution (48 %) which is considered low. The isotopic ratio ( 234 U: 238 U) in all stages of hydrometallurgical process was not much different from unity indicating lack of fractionation. Upon comparing the levels of impurities in different form of crude yellow cakes, it was found that the lowest levels were measured in hydrated trioxide (UO 3 ·xH 2 O). This implies that saturated magnesia is least aggressive relative to other precipitants and gives relatively pure crude cake. Therefore, it was used as an index to judge the relative purity of other forms of yellow cakes by taking the respective elemental ratios. The levels of impurities (Fe, Zn, Mn, Cu, Ni, Cd and Pb) in the purified yellow cake were found comparable with those specified for commercial products. (author)

Absolute M1 and E2 Transition Probabilities in 233U

International Nuclear Information System (INIS)

Malmskog, S.G.; Hoejeberg, M.

1967-08-01

Using the delayed coincidence technique, the following half lives have been determined for different excited states in 233 U: T 1/2 (311.9 keV level) = (1.20 ± 0.15) x 10 -10 sec, T 1/2 (340.5 keV level) = (5.2 ± 1.0) x 10 -11 sec, T 1/2 (398.6 keV level) = (5.5 ± 2.0) x 10 -11 sec and T 1/2 (415.8 keV level) -11 sec. From these half life determinations, together with earlier known electron intensities and conversion coefficients, 22 reduced B(Ml) and B(E2) transition probabilities (including 9 limits) have been deduced. The rotational transitions give information on the parameters δ and (g K - g R ) . The experimental M1 and E2 transition rates between members of different bands have been analysed in terms of the predictions of the Nilsson model, taking also pairing correlations and Coriolis coupling effects into account

Analysis and enhancement of flexural wave stop bands in 2D periodic plates

Energy Technology Data Exchange (ETDEWEB)

Song, Yubao [Laboratory of Science and Technology on Integrated Logistics Support, National University of Defense Technology, 410073 Changsha (China); The Marcus Wallenberg Laboratory for Sound and Vibration Research, KTH – The Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Feng, Leping [The Marcus Wallenberg Laboratory for Sound and Vibration Research, KTH – The Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Wen, Jihong, E-mail: wenjihong_nudt1@vip.sina.com [Laboratory of Science and Technology on Integrated Logistics Support, National University of Defense Technology, 410073 Changsha (China); Yu, Dianlong; Wen, Xisen [Laboratory of Science and Technology on Integrated Logistics Support, National University of Defense Technology, 410073 Changsha (China)

2015-07-17

The band structure and enhancement of flexural wave stop bands in a 2D periodic plate are investigated. A unified method for analysing and designing the stop band of the plates with various attached structures is proposed. The effect of attached structures is considered based on their equivalent parameters (added equivalent mass and equivalent moment of inertia). The influences of the equivalent parameters on the band structures are studied. Three cases are considered: adding pure equivalent mass, pure equivalent moment of inertia and the combination of these two. The stop bands are enhanced via the multi interaction between the host plate and the attached structure. The enhancement pattern is determined, and several ways to obtain a wider combined stop band are presented. The frequency response functions of corresponding finite periodic plates are calculated to verify the stop bands and their enhancement in a number of typical cases. - Highlights: • A unified method for studying the stop band of the plates with various simplified attached structures is proposed. • The enhancement of flexural wave stop bands in a 2D phononic plate is investigated. • The stop bands are widened via multi interaction between the host plate and the attached structure. • The enhancement pattern is determined and several ways to get a wider stop band are presented.

Determination of uranium and thorium in rock samples from Harargaj Anticline by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Rahman, M.; Molla, N.I.; Sharif, A.K.M.; Basunia, S.; Islam, S.; Miah, R.U.; Hossain, S.M.; Chowdhury, M.I.; Bhuiyan, A.D.; Stegnar, P.

1993-01-01

Uranium and thorium were determined in geological materials such as radioactive rock samples collected from the Harargaj Anticline in Moulavi Bazar. The pure instrumental neutron activation analysis (INAA) technique was used in qualitative and quantitative analysis of the rock samples for U and Th. The samples were properly prepared together with their standards and simultaneously irradiated in a neutron flux of the order of 10 12 n*cm -2 *s -1 using the TRIGA MARK II research reactor facility at the AERE, Savar, Dhaka. After activation the samples were subjected to γ-ray spectrometry using a high purity germanium detection system. As a result of the analysis, U and Th could be determined. The data are consistent with the values reported by the ground radiometric survey group for some of the samples. (author) 7 refs.; 1 fig.; 2 tabs