Development of bioconcrete material using an enrichment culture of novel thermophilic anaerobic bacteria.

PubMed

Ghosh, P; Mandal, S; Pal, S; Bandyopadhyaya, G; Chattopadhyay, B D

2006-04-01

In the biosphere, bacteria can function as geo-chemical agents, promoting the dispersion, fractionation and/or concentration of materials. Microbial mineral precipitation is resulted from metabolic activities of microorganisms. Based on this biomineralogy concept, an attempt has been made to develop bioconcrete material incorporating of an enrichment culture of thermophilic and anaerobic bacteria within cement-sand mortar/concrete. The results showed a significant increase in compressive strength of both cement-sand mortar and concrete due to the development of filler material within the pores of cement sand matrix. Maximum strength was observed at concentration 10(5)cell/ml of water used in mortar/concrete. Addition of Escherichia coil or media composition on mortar showed no such improvement in strength.

Selective weathering of shocked minerals and chondritic enrichment of the Martian fines

NASA Technical Reports Server (NTRS)

Boslough, M. B.

1987-01-01

In a recent paper, Boslough and Cygan reported the observation of shock-enhanced chemical weathering kinetics of three silicate minerals. Based on the experimental data and on those of Tyburczy and Ahrens for enhanced dehydration kinetics of shocked serpentine, a mechnaism is proposed by which shock-activated minerals are selectively weathered on the surface of Mars. The purpose of the present abstract is to argue on the basis of relative volumes of shocked materials that, as a direct consequence of selective weathering, the composition of the weathered surface units on Mars should be enriched in meteoritic material.

10 CFR 110.32 - Information required in an application for a specific license/NRC Form 7.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., including the supplier of equipment or material, if different from the applicant. (c) Country of origin of...) and its chemical and physical form. (2) For enriched uranium, the maximum weight percentage of..., physical and chemical characteristics, route of transit of shipment, classification (as defined in § 61.55...

10 CFR 110.32 - Information required in an application for a specific license/NRC Form 7.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., including the supplier of equipment or material, if different from the applicant. (c) Country of origin of...) and its chemical and physical form. (2) For enriched uranium, the maximum weight percentage of..., physical and chemical characteristics, route of transit of shipment, classification (as defined in § 61.55...

10 CFR 110.32 - Information required in an application for a specific license/NRC Form 7.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., including the supplier of equipment or material, if different from the applicant. (c) Country of origin of...) and its chemical and physical form. (2) For enriched uranium, the maximum weight percentage of..., physical and chemical characteristics, route of transit of shipment, classification (as defined in § 61.55...

Polymer-Enriched 3D Graphene Foams for Biomedical Applications.

PubMed

Wang, Jun Kit; Xiong, Gordon Minru; Zhu, Minmin; Özyilmaz, Barbaros; Castro Neto, Antonio Helio; Tan, Nguan Soon; Choong, Cleo

2015-04-22

Graphene foams (GFs) are versatile nanoplatforms for biomedical applications because of their excellent physical, chemical, and mechanical properties. However, the brittleness and inflexibility of pristine GF (pGF) are some of the important factors restricting their widespread application. Here, a chemical-vapor-deposition-assisted method was used to synthesize 3D GFs, which were subsequently spin-coated with polymer to produce polymer-enriched 3D GFs with high conductivity and flexibility. Compared to pGF, both poly(vinylidene fluoride)-enriched GF (PVDF/GF) and polycaprolactone-enriched GF (PCL/GF) scaffolds showed improved flexibility and handleability. Despite the presence of the polymers, the polymer-enriched 3D GF scaffolds retained high levels of electrical conductivity because of the presence of microcracks that allowed for the flow of electrons through the material. In addition, polymer enrichment of GF led to an enhancement in the formation of calcium phosphate (Ca-P) compounds when the scaffolds were exposed to simulated body fluid. Between the two polymers tested, PCL enrichment of GF resulted in a higher in vitro mineralization nucleation rate because the oxygen-containing functional group of PCL had a higher affinity for Ca-P deposition and formation compared to the polar carbon-fluorine (C-F) bond in PVDF. Taken together, our current findings are a stepping stone toward future applications of polymer-enriched 3D GFs in the treatment of bone defects as well as other biomedical applications.

Fire extinguishment in oxygen enriched atmospheres

NASA Technical Reports Server (NTRS)

Robertson, A. F.; Rappaport, M. W.

1973-01-01

Current state-of-the-art of fire suppression and extinguishment techniques in oxygen enriched atmosphere is reviewed. Four classes of extinguishment action are considered: cooling, separation of reactants, dilution or removal of fuel, and use of chemically reactive agents. Current practice seems to show preference for very fast acting water spray applications to all interior surfaces of earth-based chambers. In space, reliance has been placed on fire prevention methods through the removal of ignition sources and use of nonflammable materials. Recommendations are made for further work related to fire suppression and extinguishment in oxygen enriched atmospheres, and an extensive bibliography is appended.

Based on a True Story: Using Movies as Source Material for General Chemistry Reports

NASA Astrophysics Data System (ADS)

Griep, Mark A.; Mikasen, Marjorie L.

2005-10-01

Research for chemical reports and case study analysis of chemical topics are two commonly used learning activities to engage and enrich student understanding of the content in introductory chemistry courses. Even though movies are excellent vehicles for exploring the human dimension of events, they have been used only sparingly as source material in introductory science courses. One reason for this sparing use has been the lack of a list of suitable movies. To fill this void, a list of one dozen highly rated movies is presented. The focus of these movies is either a scientist's chemical research or the societal impact of some chemical compound. The method by which two of these movies were used as source material for a written report in a general chemistry course is described. The student response to the exercise was enthusiastic.

Assessment of the Interstellar Processes Leading to Deuterium Enrichment in Meteoritic Organics

NASA Technical Reports Server (NTRS)

Sandford, Scott A.; Bernstein, Max P.; Dworkin, Jason P.; DeVincenzi, Donald L. (Technical Monitor)

2001-01-01

The presence of isotopic anomalies is the most unequivocal demonstration that meteoritic material contains circumstellar or interstellar components. In the case of organic compounds in meteorites and interplanetary dust particles (IDPs), the most useful isotopic tracer has been deuterium (D). We discuss four processes that are expected to lead to D enrichment in interstellar materials and describe how their unique characteristics can be used to assess their relative importance for the organics in meteorites. These enrichment processes are low temperature gas phase ion-molecule reactions, low temperature gas-grain reactions, gas phase unimolecular photodissociation, and ultraviolet photolysis in D-enriched ice mantles. Each of these processes is expected to be associated with distinct regiochemical signatures (D placement on the product molecules, correlation with specific chemical functionalities, etc.), especially in the molecular population of polycyclic aromatic hydrocarbons (PAHs). We describe these differences and discuss how they may be used to delineate the various interstellar processes that may have contributed to meteoritic D enrichments. We also briefly discuss how these processes may affect the isotopic distributions in C, 0, and N in the same compounds.

Implications of Barium Abundances for the Chemical Enrichment of Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Duggan, Gina; Kirby, Evan N.

2018-06-01

There are many candidate sites of the r-process: core-collapse supernovae (including rare magnetorotational core-collapse supernovae), neutron star mergers (NSMs), and neutron star/black hole mergers. The chemical enrichment of galaxies—specifically dwarf galaxies—helps distinguish between these sources based on the continual build-up of r-process elements. The existence of several nearby dwarf galaxies allows us to measure robust chemical abundances for galaxies with different star formation histories. Dwarf galaxies are especially useful because simple chemical evolution models can be used to determine the sources of r-process material. We have measured the r-process element barium with Keck/DEIMOS medium-resolution spectroscopy. We will present the largest sample of barium abundances (more than 200 stars) in dwarf galaxies ever assembled. We measure [Ba/Fe] as a function of [Fe/H] in this sample and compare with existing [alpha/Fe] measurements. We have found that a large contribution of barium needs to occur at timescales similar to Type Ia supernovae in order to recreate our observed abundances, namely the flat or slightly rising trend of [Ba/Fe] vs. [Fe/H]. We conclude that neutron star mergers are the main contribution of r-process enrichment in dwarf galaxies.

Searching for Life in Death Valley (and Other Deserts) - Microchemical Investigations on Desert Varnish

NASA Astrophysics Data System (ADS)

Andreae, M. O.; Al-Amri, A. M.; Jochum, K. P.; Kappl, M.; Kilcoyne, A. D.; Macholdt, D.; Müller, M.; Pöhlker, C.; Weber, B.; Weigand, M.

2014-12-01

Desert varnishes are thin, shiny, blackish to brown coatings frequently found on the surfaces of exposed rocks in deserts around the globe. They have been proposed as terrestrial analogues of superficial hematite enrichments observed on Mars. While the first scientific studies of such varnishes go back to Darwin and von Humboldt, and intensive studies by a variety of techniques have been conducted over the last few decades, their origin is still a matter of debate. Microscopic and molecular studies have shown the presence of fungi and bacteria, but it is still unclear whether they are involved in the formation of the varnish material or just opportunistic colonizers on available surfaces. We have analysed samples of desert varnish from sites in Death Valley, the Mojave Desert, the Negev of Israel, Central Saudi Arabia, and the Succulent Karoo by a variety of microanalytical techniques. Measurements by UV-femtosecond Laser Ablation Inductively Coupled Plasma Mass Spectrometry show enrichments of manganese, iron, barium and other elements. Isotopic and trace chemical signatures show that these enriched elements cannot originate from the rocks that form the substrate on which the crusts have been deposited, but most likely are the result of (bio?)chemical transformation of windblown material. For a more detailed investigation of the internal structure of the crusts, we prepared ultra-thin sections (~100 nm) using focused ion beam slicing and analysed them by Scanning Transmission X-ray Microscopy with Near-Edge X-ray Absorption Fine Structure spectroscopy (STXM-NEXAFS). This technique revealed layered or chaotic structures consisting of alternating Mn and Fe-rich zones. Some of these layers are enriched in organic carbon with spectral features dominated by aromatic and carboxylate functionalities, indicating a biological origin of some of the crust material. Some crusts also show cavities that are lined with similar organic material. Since the age of these crusts is of the order of 100-10,000 of years, this organic matter must represent fossil evidence that has survived intensive solar radiation, extreme temperatures, and chemical weathering over long periods of time within microns from the varnish surface.

Nanoparticulate, sub-micron and micron sized particles emanating from hydrothermal vents

NASA Astrophysics Data System (ADS)

Luther, G. W., III; Gartman, A.; Findlay, A.; Yucel, M.; Chan, C. S. Y.

2015-12-01

Recent data from Geotraces cruises over the MAR and SEPR indicate dissolved and particulate Fe enrichment in waters 1000 and 4000 km from their vent sources, respectively. Deep-sea hydrothermal vents and the waters in the reactive mixing zone above vent orifices have been suggested to be an important source of fine material that can pass through normal filters (0.2 and 0.4 μm). In this work, nanoparticles are defined operationally as that which can pass through a 0.2 μm filter. We investigated two vent sites (Lau Basin and the MAR). Chimneys from both vent sites have fluids that can be sulfide rich or metal rich. We also present chemical and physical chemical data (SEM-EDS, TEM, XRD, EELS) showing some of the materials found in these (nano)particulate phases including pyrite, metal sulfides, silicate and aluminosilicate material. Enrichment of Mg and K in the latter suggest that reverse weathering may occur in the waters within 1-2 meters of the vent orifice where vent waters mix with cold oxygenated bottom waters.

Sedimentary provenance of Maastrichtian oil shales, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Fathy, Douaa; Wagreich, Michael; Mohamed, Ramadan S.; Zaki, Rafat

2017-04-01

Maastrichtian oil shales are distributed within the Central Eastern Desert in Egypt. In this study elemental geochemical data have been applied to investigate the probable provenance of the sedimentary detrital material of the Maastrichtian oil shale beds within the Duwi and the Dakhla formations. The Maastrichtian oil shales are characterized by the enrichment in Ca, P, Mo, Ni, Zn, U, Cr and Sr versus post-Archean Australian shales (PAAS). The chondrite-normalized patterns of the Maastrichtian oil shale samples are showing LREE enrichment, HREE depletion, slightly negative Eu anomaly, no obvious Ce anomaly and typical shale-like PAAS-normalized patterns. The total REE well correlated with Si, Al, Fe, K and Ti, suggesting that the REE of the Maastrichtian oil shales are derived from terrigenous source. Chemical weathering indices such as Chemical Index of Alteration (CIA), Chemical Proxy of Alteration (CPA) and Plagioclase Index of Alteration (PIA) indicate moderate to strong chemical weathering. We suggest that the Maastrichtian oil shale is mainly derived from first cycle rocks especially intermediate rocks without any significant inputs from recycled or mature sources. The proposed data illustrated the impact of the parent material composition on evolution of oil shale chemistry. Furthermore, the paleo-tectonic setting of the detrital source rocks for the Maastrichtian oil shale is probably related to Proterozoic continental island arcs

[Study on essential oil separation from Forsythia suspensa oil-bearing water body based on vapor permeation membrane separation technology].

PubMed

Zhang, Qian; Zhu, Hua-Xu; Tang, Zhi-Shu; Pan, Yong-Lan; Li, Bo; Fu, Ting-Ming; Yao, Wei-Wei; Liu, Hong-Bo; Pan, Lin-Mei

2018-04-01

To investigate the feasibility of vapor permeation membrane technology in separating essential oil from oil-water extract by taking the Forsythia suspensa as an example. The polydimethylsiloxane/polyvinylidene fluoride (PDMS/PVDF) composite flat membrane and a polyvinylidene fluoride (PVDF) flat membrane was collected as the membrane material respectively. Two kinds of membrane osmotic liquids were collected by self-made vapor permeation device. The yield of essential oil separated and enriched from two kinds of membrane materials was calculated, and the microscopic changes of membrane materials were analyzed and compared. Meanwhile, gas chromatography-mass spectrometry (GC-MS) was used to compare and analyze the differences in chemical compositions of essential oil between traditional steam distillation, PVDF membrane enriched method and PDMS/PVDF membrane enriched method. The results showed that the yield of essential oil enriched by PVDF membrane was significantly higher than that of PDMS/PVDF membrane, and the GC-MS spectrum showed that the content of main compositions was higher than that of PDMS/PVDF membrane; The GC-MS spectra showed that the components of essential oil enriched by PVDF membrane were basically the same as those obtained by traditional steam distillation. The above results showed that vapor permeation membrane separation technology shall be feasible for the separation of Forsythia essential oil-bearing water body, and PVDF membrane was more suitable for separation and enrichment of Forsythia essential oil than PDMS/PVDF membrane. Copyright© by the Chinese Pharmaceutical Association.

Tags to Track Illicit Uranium and Plutonium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haire, M. Jonathan; Forsberg, Charles W.

2007-07-01

With the expansion of nuclear power, it is essential to avoid nuclear materials from falling into the hands of rogue nations, terrorists, and other opportunists. This paper examines the idea of detection and attribution tags for nuclear materials. For a detection tag, it is proposed to add small amounts [about one part per billion (ppb)] of {sup 232}U to enriched uranium to brighten its radioactive signature. Enriched uranium would then be as detectable as plutonium and thus increase the likelihood of intercepting illicit enriched uranium. The use of rare earth oxide elements is proposed as a new type of 'attribution'more » tag for uranium and thorium from mills, uranium and plutonium fuels, and other nuclear materials. Rare earth oxides are chosen because they are chemically compatible with the fuel cycle, can survive high-temperature processing operations in fuel fabrication, and can be chosen to have minimal neutronic impact within the nuclear reactor core. The mixture of rare earths and/or rare earth isotopes provides a unique 'bar code' for each tag. If illicit nuclear materials are recovered, the attribution tag can identify the source and lot of nuclear material, and thus help police reduce the possible number of suspects in the diversion of nuclear materials based on who had access. (authors)« less

Following isotopes in pulse-chase enriched aspen seedlings

NASA Astrophysics Data System (ADS)

Norris, C. E.; Wasylishen, R. E.; Landhäusser, S.; Quideau, S. A.

2011-12-01

One method to quantitatively trace biogeochemical fluxes through ecosystems, such as organic matter decomposition, is to use plant material enriched with stable isotopes. However, as plant macromolecules are known to vary in their rate of formation and decomposition, both the enrichment levels and the location of enrichment within the plant material should be characterized prior to decomposition and tracing studies. Aspen (Populus tremuloides Michx.) is a common tree species with a diverse organic matter chemical structure found in the western Canadian boreal forest. This study used a multi pulse and multi chase enrichment of stable isotopes (15N and 13C) on aspen seedlings to determine the seedling enrichment, isotope movement among plant tissues and translocation of isotopes within plant macromolecules e.g., carbohydrates and lignin. As expected, all tissues experienced increased enrichment with multiple pulses. An initial enrichment with 13C was observed in the leaves followed by translocation to the stems and roots while the 15N moved upward from the roots to leaves. The macromolecular chemistry of the organic carbon was further characterized using 13C solid state nuclear magnetic resonance spectroscopy. After the initial two hour chase period enrichment of the O-alkyl type (carbohydrate) carbon within the leaves was identified, followed by redistribution to more complex carbon compounds after the one week chase period. Root and stem tissues did not show the same pattern. Rather, changes in 13C enrichment were observed in shifting ethyl and methyl alkyl (lipid) carbon peak intensities for the stem samples while roots did not preferentially allocate 13C to a specific macromolecule. These results confirm that stable isotope enrichment of plants was non-uniform across macromolecules and tissue types. Enrichment of aspen seedlings was therefore dependant on the pulse-chase sequence used.

Mesoporous Silica Chips for Selective Enrichment and Stabilization of Low Molecular Weight Proteome

PubMed Central

Bouamrani, Ali; Hu, Ye; Tasciotti, Ennio; Li, Li; Chiappini, Ciro; Liu, Xuewu; Ferrari, Mauro

2010-01-01

The advanced properties of mesoporous silica have been demonstrated in applications which include chemical sensing, filtration, catalysis, drug-delivery and selective biomolecular uptake. These properties depend on the architectural, physical and chemical properties of the material, which in turn are determined by the processing parameters in evaporation-induced self-assembly. In this study, we introduce a combinatorial approach for the removal of the high molecular weight proteins and for the specific isolation and enrichment of low molecular weight species. This approach is based on Mesoporous Silica Chips able to fractionate, selectively harvest and protect from enzymatic degradation, peptides and proteins present in complex human biological fluids. We present the characterization of the harvesting properties of a wide range of mesoporous chips using a library of peptides and proteins standard and their selectivity on the recovery of serum peptidome. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we established the correlation between the harvesting specificity and the physico-chemical properties of mesoporous silica surfaces. The introduction of this mesoporous material with fine controlled properties will provide a powerful platform for proteomics application offering a rapid and efficient methodology for low molecular weight biomarker discovery. PMID:20013801

Effect of Start-Up Strategies and Electrode Materials on Carbon Dioxide Reduction on Biocathodes

PubMed Central

Singh, Abhijeet; Hermansson, Malte; Persson, Frank; Schnürer, Anna; Wilén, Britt-Marie; Modin, Oskar

2017-01-01

ABSTRACT The enrichment of CO2-reducing microbial biocathodes is challenging. Previous research has shown that a promising approach could be to first enrich bioanodes and then lower the potential so the electrodes are converted into biocathodes. However, the effect of such a transition on the microbial community on the electrode has not been studied. The goal of this study was thus to compare the start-up of biocathodes from preenriched anodes with direct start-up from bare electrodes and to investigate changes in microbial community composition. The effect of three electrode materials on the long-term performance of the biocathodes was also investigated. In this study, preenrichment of acetate-oxidizing bioanodes did not facilitate the start-up of biocathodes. It took about 170 days for the preenriched electrodes to generate substantial cathodic current, compared to 83 days for the bare electrodes. Graphite foil and carbon felt cathodes produced higher current at the beginning of the experiment than did graphite rods. However, all electrodes produced similar current densities at the end of the over 1-year-long study (2.5 A/m2). Methane was the only product detected during operation of the biocathodes. Acetate was the only product detected after inhibition of the methanogens. Microbial community analysis showed that Geobacter sp. dominated the bioanodes. On the biocathodes, the Geobacter sp. was succeeded by Methanobacterium spp., which made up more than 80% of the population. After inhibition of the methanogens, Acetobacterium sp. became dominant on the electrodes (40% relative abundance). The results suggested that bioelectrochemically generated H2 acted as an electron donor for CO2 reduction. IMPORTANCE In microbial electrochemical systems, living microorganisms function as catalysts for reactions on the anode and/or the cathode. There is a variety of potential applications, ranging from wastewater treatment and biogas generation to production of chemicals. Systems with biocathodes could be used to reduce CO2 to methane, acetate, or other high-value chemicals. The technique can be used to convert solar energy to chemicals. However, enriching biocathodes that are capable of CO2 reduction is more difficult and less studied than enriching bioanodes. The effect of different start-up strategies and electrode materials on the microbial communities that are enriched on biocathodes has not been studied. The purpose of this study was to investigate two different start-up strategies and three different electrode materials for start-up and long-term operation of biocathodes capable of reducing CO2 to valuable biochemicals. PMID:29222104

Centrifugal partition chromatography enables selective enrichment of trimeric and tetrameric proanthocyanidins for biomaterial development.

PubMed

Phansalkar, Rasika S; Nam, Joo-Won; Chen, Shao-Nong; McAlpine, James B; Leme, Ariene A; Aydin, Berdan; Bedran-Russo, Ana-Karina; Pauli, Guido F

2018-02-02

Proanthocyanidins (PACs) find wide applications for human use including food, cosmetics, dietary supplements, and pharmaceuticals. The chemical complexity associated with PACs has triggered the development of various chromatographic techniques, with countercurrent separation (CCS) gaining in popularity. This study applied the recently developed DESIGNER (Depletion and Enrichment of Select Ingredients Generating Normalized Extract Resources) approach for the selective enrichment of trimeric and tetrameric PACs using centrifugal partition chromatography (CPC). This CPC method aims at developing PAC based biomaterials, particularly for their application in restoring and repairing dental hard tissue. A general separation scheme beginning with the depletion of polymeric PACs, followed by the removal of monomeric flavan-3-ols and a final enrichment step produced PAC trimer and tetramer enriched fractions. A successful application of this separation scheme is demonstrated for four polyphenol rich plant sources: grape seeds, pine bark, cinnamon bark, and cocoa seeds. Minor modifications to the generic DESIGNER CCS method were sufficient to accommodate the varying chemical complexities of the individual source materials. The step-wise enrichment of PAC trimers and tetramers was monitored using normal phase TLC and Diol-HPLC-UV analyses. CPC proved to be a reliable tool for the selective enrichment of medium size oligomeric PACs (OPACs). This method plays a key role in the development of dental biomaterials considering its reliability and reproducibility, as well as its scale-up capabilities for possible larger-scale manufacturing. Copyright © 2017 Elsevier B.V. All rights reserved.

Sea spray aerosol chemical composition: elemental and molecular mimics for laboratory studies of heterogeneous and multiphase reactions.

PubMed

Bertram, Timothy H; Cochran, Richard E; Grassian, Vicki H; Stone, Elizabeth A

2018-04-03

Sea spray aerosol particles (SSA), formed through wave breaking at the ocean surface, contribute to natural aerosol particle concentrations in remote regions of Earth's atmosphere, and alter the direct and indirect effects of aerosol particles on Earth's radiation budget. In addition, sea spray aerosol serves as suspended surface area that can catalyze trace gas reactions. It has been shown repeatedly that sea spray aerosol is heavily enriched in organic material compared to the surface ocean. The selective enrichment of organic material complicates the selection of representative molecular mimics of SSA for laboratory or computational studies. In this review, we first provide a short introduction to SSA formation processes and discuss chemical transformations of SSA that occur in polluted coastal regions and remote pristine air. We then focus on existing literature of the chemical composition of nascent SSA generated in controlled laboratory experiments and field investigations. We combine the evidence on the chemical properties of nascent SSA with literature measurements of SSA water uptake to assess SSA molecular composition and liquid water content. Efforts to speciate SSA organic material into molecular classes and specific molecules have led to the identification of saccharides, alkanes, free fatty acids, anionic surfactants, dicarboxylic acids, amino acids, proteinaceous matter, and other large macromolecules. However to date, less than 25% of the organic mass of nascent SSA has been quantified at a molecular level. As discussed here, quantitative measurements of size resolved elemental ratios, combined with determinations of water uptake properties, provides unique insight on the concentration of ions within SSA as a function of particle size, pointing to a controlling role for relative humidity and the hygroscopicity of SSA organic material at small particle diameters.

Chemical and magnetic properties of rapidly cooled metastable ferri-ilmenite solid solutions - IV: the fine structure of self-reversed thermoremanent magnetization

NASA Astrophysics Data System (ADS)

Robinson, Peter; McEnroe, S. A.; Fabian, K.; Harrison, R. J.; Thomas, C. I.; Mukai, H.

2014-03-01

Magnetic experiments, a Monte Carlo simulation and transmission electron microscopy observations combine to confirm variable chemical phase separation during quench and annealing of metastable ferri-ilmenite compositions, caused by inhomogeneous Fe-Ti ordering and anti-ordering. Separation begins near interfaces between growing ordered and anti-ordered domains, the latter becoming progressively enriched in ilmenite component, moving the Ti-impoverished hematite component into Fe-enriched diffusion waves near the interfaces. Even when disordered regions are eliminated, Fe-enriched waves persist and enlarge on anti-phase boundaries between growing and shrinking ordered and anti-ordered domains. Magnetic results and conceptual models show that magnetic ordering with falling T initiates in the Fe-enriched wave crests. Although representing only a tiny fraction of material, identified at highest Ts on a field-cooling curve, they control the `pre-destiny' of progressive magnetization at lower T. They can provide a positive magnetic moment in a minority of ordered ferrimagnetic material, which, by exchange coupling, then creates a self-reversed negative moment in the remaining majority. Four Ts or T ranges are recognized on typical field-cooling curves: TPD is the T range of `pre-destination'; TC is the predominant Curie T where major positive magnetization increases sharply; TMAX is where magnetization reaches a positive maximum, beyond which it is outweighed by self-reversed magnetization and TZM is the T where total magnetization passes zero. Disposition of these Ts on cooling curves indicate the fine structure of self-reversed thermoremanent magnetization. These results confirm much earlier suspicions that the `x-phase' responsible for self-reversed magnetization resides in Fe-enriched phase boundaries.

Observations of Nitrogen Fractionation in Prestellar Cores: Nitriles Tracing Interstellar Chemistry

NASA Technical Reports Server (NTRS)

Milam, S. N.; Charnley, S. B.

2012-01-01

Primitive materials provide important clues on the processes that occurred during the formation and early evolution of the Solar System. Space-based and ground-based observations of cometary comae show that comets appear to contain a mixture of the products of both interstellar and nebular chemistries. Significant 15-nitrogen enrichments have been measured in CN and HCN towards a number of comets and may suggest an origin of interstellar chemical fractionation. Additionally, large N-15 enhancements are found in meteorites and has also led to to the view that the N-15 traces material formed in the interstellar medium (ISM), although multiple sources cannot be excluded. Here, we show the results of observations of the nitrogen and carbon fractionation in prestellar cores for various N-bearing species to decipher the origin of primitive material isotopic enrichments.

Spectral properties of Titan's impact craters imply chemical weathering of its surface

PubMed Central

Barnes, J. W.; Sotin, C.; MacKenzie, S.; Soderblom, J. M.; Le Mouélic, S.; Kirk, R. L.; Stiles, B. W.; Malaska, M. J.; Le Gall, A.; Brown, R. H.; Baines, K. H.; Buratti, B.; Clark, R. N.; Nicholson, P. D.

2015-01-01

Abstract We examined the spectral properties of a selection of Titan's impact craters that represent a range of degradation states. The most degraded craters have rims and ejecta blankets with spectral characteristics that suggest that they are more enriched in water ice than the rims and ejecta blankets of the freshest craters on Titan. The progression is consistent with the chemical weathering of Titan's surface. We propose an evolutionary sequence such that Titan's craters expose an intimate mixture of water ice and organic materials, and chemical weathering by methane rainfall removes the soluble organic materials, leaving the insoluble organics and water ice behind. These observations support the idea that fluvial processes are active in Titan's equatorial regions. PMID:27656006

Agricultural Supplies and Services. Program Planning Guide: Volume 2.

ERIC Educational Resources Information Center

Welton, Richard; Marks, Michael

The program planning guide for agricultural supplies and services was written to assist Applied Biological and Agricultural Occupations (ABAO) teachers in enriching existing programs and/or to provide the basis for expansion of offerings to include additional materials for the cluster areas of agricultural chemicals, feeds, seeds, fertilizers, and…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Back, H. O.; Bottenus, D. R.; Clayton, C.

The next generation of 136Xe neutrinoless double beta decay experiments will require on the order of 5 tons of enriched 136Xe. By estimating the relative volatilities of the xenon isotopes and using standard chemical engineering techniques we explore the feasibility of using cryogenic distillation to produce 5 tons of 80% enriched 136Xe in 5-6 years. With current state-of-the-art distillation column packing materials we can estimate the total height of a traditional cryogenic distillation column. We also, report on how Micro Channel Distillation may reduce the overall size of a distillation system for 136Xe production.

Revised models of interstellar nitrogen isotopic fractionation

NASA Astrophysics Data System (ADS)

Wirström, E. S.; Charnley, S. B.

2018-03-01

Nitrogen-bearing molecules in cold molecular clouds exhibit a range of isotopic fractionation ratios and these molecules may be the precursors of 15N enrichments found in comets and meteorites. Chemical model calculations indicate that atom-molecular ion and ion-molecule reactions could account for most of the fractionation patterns observed. However, recent quantum-chemical computations demonstrate that several of the key processes are unlikely to occur in dense clouds. Related model calculations of dense cloud chemistry show that the revised 15N enrichments fail to match observed values. We have investigated the effects of these reaction rate modifications on the chemical model of Wirström et al. (2012) for which there are significant physical and chemical differences with respect to other models. We have included 15N fractionation of CN in neutral-neutral reactions and also updated rate coefficients for key reactions in the nitrogen chemistry. We find that the revised fractionation rates have the effect of suppressing 15N enrichment in ammonia at all times, while the depletion is even more pronounced, reaching 14N/15N ratios of >2000. Taking the updated nitrogen chemistry into account, no significant enrichment occurs in HCN or HNC, contrary to observational evidence in dark clouds and comets, although the 14N/15N ratio can still be below 100 in CN itself. However, such low CN abundances are predicted that the updated model falls short of explaining the bulk 15N enhancements observed in primitive materials. It is clear that alternative fractionating reactions are necessary to reproduce observations, so further laboratory and theoretical studies are urgently needed.

Germanium abundances in lunar basalts: Evidence of mantle metasomatism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickinson, T.; Taylor, G.J.; Keil, T.K.

1988-01-01

To fill in gaps in the present Ge data base, mare basalts were analyzed for Ge and other elements by RNAA and INAA. Mare basalts from Apollo 11, 12, 15, 17 landing sites are rather uniform in Ge abundance, but Apollo 14 aluminous mare basalts and KREEP are enriched in Ge by factors of up to 300 compared to typical mare basalts. These Ge enrichments are not associated with other siderophile element enrichments and, thus, are not due to differences in the amount of metal segregated during core formation. Based on crystal-chemical and inter-element variations, it does not appear thatmore » the observed Ge enrichments are due to silicate liquid immiscibility. Elemental ratios in Apollo 14 aluminous mare basalts, green and orange glass, average basalts and KREEP suggest that incorporation of late accreting material into the source regions or interaction of the magmas with primitive undifferentiated material is not a likely cause for the observed Ge enrichments. We speculate that the most plausible explanation for these Ge enrichments is complexing and concentration of Ge by F, Cl or S in volatile phases. In this manner, the KREEP basalt source regions may have been metasomatized and Apollo 14 aluminous mare basalt magmas may have become enriched in Ge by interacting with these metasomatized areas. The presence of volatile- and Ge-rich regions in the Moon suggests that the Moon was never totally molten. 71 refs., 1 fig., 6 tabs.« less

Chemical and process mineralogical characterizations of spent lithium-ion batteries: an approach by multi-analytical techniques.

PubMed

Zhang, Tao; He, Yaqun; Wang, Fangfang; Ge, Linhan; Zhu, Xiangnan; Li, Hong

2014-06-01

Mineral processing operation is a critical step in any recycling process to realize liberation, separation and concentration of the target parts. Developing effective recycling methods to recover all the valuable parts from spent lithium-ion batteries is in great necessity. The aim of this study is to carefully undertake chemical and process mineralogical characterizations of spent lithium-ion batteries by coupling several analytical techniques to provide basic information for the researches on effective mechanical crushing and separation methods in recycling process. The results show that the grade of Co, Cu and Al is fairly high in spent lithium ion batteries and up to 17.62 wt.%, 7.17 wt.% and 21.60 wt.%. Spent lithium-ion batteries have good selective crushing property, the crushed products could be divided into three parts, they are Al-enriched fraction (+2 mm), Cu and Al-enriched fraction (-2+0.25 mm) and Co and graphite-enriched fraction (-0.25 mm). The mineral phase and chemical state analysis reveal the electrode materials recovered from -0.25 mm size fraction keep the original crystal forms and chemical states in lithium-ion batteries, but the surface of the powders has been coated by a certain kind of hydrocarbon. Based on these results a flowsheet to recycle spent LiBs is proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tox21 Enricher: Web-based Chemical/Biological Functional Annotation Analysis Tool Based on Tox21 Toxicity Screening Platform.

PubMed

Hur, Junguk; Danes, Larson; Hsieh, Jui-Hua; McGregor, Brett; Krout, Dakota; Auerbach, Scott

2018-05-01

The US Toxicology Testing in the 21st Century (Tox21) program was established to develop more efficient and human-relevant toxicity assessment methods. The Tox21 program screens >10,000 chemicals using quantitative high-throughput screening (qHTS) of assays that measure effects on toxicity pathways. To date, more than 70 assays have yielded >12 million concentration-response curves. The patterns of activity across assays can be used to define similarity between chemicals. Assuming chemicals with similar activity profiles have similar toxicological properties, we may infer toxicological properties based on its neighbourhood. One approach to inference is chemical/biological annotation enrichment analysis. Here, we present Tox21 Enricher, a web-based chemical annotation enrichment tool for the Tox21 toxicity screening platform. Tox21 Enricher identifies over-represented chemical/biological annotations among lists of chemicals (neighbourhoods), facilitating the identification of the toxicological properties and mechanisms in the chemical set. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical Mapping of Proterozoic Organic Matter at Sub-Micron Spatial Resolution

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Robert, Francois; Mostefaoui, Smail; Meibom, Anders; Selo, Madeleine; McKay, David S.

2006-01-01

We have used a NanoSIMS ion microprobe to map sub-micron-scale distributions of carbon, nitrogen, sulfur, silicon, and oxygen in organic microfossils and laminae from the approximately 0.85 Ga Bitter Springs Formation of Australia. The data provide clues about the original chemistry of the microfossils, the silicification process, and biosignatures of specific microorganisms and microbial communities. Chemical maps of fossil unicells and filaments reveal distinct wall-and sheath-like structures enriched in C, N and S, consistent with their accepted biological origin. Surprisingly, organic laminae, previously considered to be amorphous, also exhibit filamentous and apparently compressed spheroidal structures defined by strong enrichments in C, N and S. By analogy to data from the well-preserved microfossils, these structures are interpreted as being of biological origin, most likely representing densely packed remnants of microbial mats. Because the preponderance of organic matter in Precambrian sediments is similarly "amorphous," our findings open a large body of generally neglected material to in situ structural, chemical, and isotopic study. Our results also offer new criteria for assessing biogenicity of problematic kerogenous materials and thus can be applied to assessments of poorly preserved or fragmentary organic residues in early Archean sediments and any that might occur in meteorites or other extraterrestrial samples.

A novel tantalum-based sol-gel packed microextraction syringe for highly specific enrichment of phosphopeptides in MALDI-MS applications.

PubMed

Çelikbıçak, Ömür; Atakay, Mehmet; Güler, Ülkü; Salih, Bekir

2013-08-07

A new tantalum-based sol-gel material was synthesized using a unique sol-gel synthesis pathway by PEG incorporation into the sol-gel structure without performing a calcination step. This improved its chemical and physical properties for the high capacity and selective enrichment of phosphopeptides from protein digests in complex biological media. The specificity of the tantalum-based sol-gel material for phosphopeptides was evaluated and compared with tantalum(V) oxide (Ta2O5) in different phosphopeptide enrichment applications. The tantalum-based sol-gel and tantalum(V) oxide were characterized in detail using FT-IR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), and also using a surface area and pore size analyzer. In the characterization studies, the surface morphology, pore volume, crystallinity of the materials and PEG incorporation into the sol-gel structure to produce a more hydrophilic material were successfully demonstrated. The X-ray diffractograms of the two different materials were compared and it was noted that the broad signals of the tantalum-based sol-gel clearly represented the amorphous structure of the sol-gel material, which was more likely to create enough surface area and to provide more accessible tantalum atoms for phosphopeptides to be easily adsorbed when compared with the neat and more crystalline structure of Ta2O5. Therefore, the phosphopeptide enrichment performance of the tantalum-based sol-gels was found to be remarkably higher than the more crystalline Ta2O5 in our studies. Phosphopeptides at femtomole levels could be selectively enriched using the tantalum-based sol-gel and detected with a higher signal-to-noise ratio by matrix-assisted laser desorption/ionization-mass spectrometer (MALDI-MS). Moreover, phosphopeptides in a tryptic digest of non-fat bovine milk as a complex real-world biological sample were retained with higher yield using a tantalum-based sol-gel. Additionally, the sol-gel material was packed into a standard syringe (0.5 mL) to enhance the ease of use of the sol-gel material and for the elimination of additional mixing and separation procedures during the adsorption, washing and elution steps of the enrichment procedure. It was found that up to 28 phosphopeptides in milk digest were easily detectable by MALDI-MS at femtomole levels (around 20 fmol) using the microextraction syringe within less than one minute.

Effects of natural enrichment materials on stress, memory and exploratory behavior in mice.

PubMed

Acklin, Casey J; Gault, Ruth A

2015-07-01

Environmental enrichment is an essential component of laboratory animal housing that allows animals to engage in natural behaviors in an otherwise artificial setting. Previous research by the authors suggested that, compared with synthetic enrichment materials, natural materials were associated with lower stress levels in mice. Here, the authors compare the effects of different enrichment materials on stress, memory and exploratory behavior in Swiss Webster mice. Mice that were provided with natural enrichment materials had lower stress levels, better memory and greater exploratory behavior than did mice provided with synthetic enrichment materials or with no enrichment materials. These findings suggest that provision of natural enrichment materials can improve well-being of laboratory mice.

Current perspectives of bio-ceramic technology in endodontics: calcium enriched mixture cement - review of its composition, properties and applications

PubMed Central

Nawal, Ruchika Roongta; Talwar, Sangeeta; Verma, Mahesh

2015-01-01

Advancements in bio-ceramic technology has revolutionised endodontic material science by enhancing the treatment outcome for patients. This class of dental materials conciliates excellent biocompatibility with high osseoconductivity that render them ideal for endodontic care. Few recently introduced bio-ceramic materials have shown considerable clinical success over their early generations in terms of good handling characteristics. Calcium enriched mixture (CEM) cement, Endosequence sealer, and root repair materials, Biodentine and BioAggregate are the new classes of bio-ceramic materials. The aim of this literature review is to present investigations regarding properties and applications of CEM cement in endodontics. A review of the existing literature was performed by using electronic and hand searching methods for CEM cement from January 2006 to December 2013. CEM cement has a different chemical composition from that of mineral trioxide aggregate (MTA) but has similar clinical applications. It combines the biocompatibility of MTA with more efficient characteristics, such as significantly shorter setting time, good handling characteristics, no staining of tooth and effective seal against bacterial leakage. PMID:25671207

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakel, Allen J.; Conner, Cliff; Quigley, Kevin

One of the missions of the Reduced Enrichment for Research and Test Reactors (RERTR) program (and now the National Nuclear Security Administrations Material Management and Minimization program) is to facilitate the use of low enriched uranium (LEU) targets for 99Mo production. The conversion from highly enriched uranium (HEU) to LEU targets will require five to six times more uranium to produce an equivalent amount of 99Mo. The work discussed here addresses the technical challenges encountered in the treatment of uranyl nitrate hexahydrate (UNH)/nitric acid solutions remaining after the dissolution of LEU targets. Specifically, the focus of this work is themore » calcination of the uranium waste from 99Mo production using LEU foil targets and the Modified Cintichem Process. Work with our calciner system showed that high furnace temperature, a large vent tube, and a mechanical shield are beneficial for calciner operation. One- and two-step direct calcination processes were evaluated. The high-temperature one-step process led to contamination of the calciner system. The two-step direct calcination process operated stably and resulted in a relatively large amount of material in the calciner cup. Chemically assisted calcination using peroxide was rejected for further work due to the difficulty in handling the products. Chemically assisted calcination using formic acid was rejected due to unstable operation. Chemically assisted calcination using oxalic acid was recommended, although a better understanding of its chemistry is needed. Overall, this work showed that the two-step direct calcination and the in-cup oxalic acid processes are the best approaches for the treatment of the UNH/nitric acid waste solutions remaining from dissolution of LEU targets for 99Mo production.« less

Chemical Equilibrium, Unit 2: Le Chatelier's Principle. A Computer-Enriched Module for Introductory Chemistry. Student's Guide and Teacher's Guide.

ERIC Educational Resources Information Center

Jameson, A. Keith

Presented are the teacher's guide and student materials for one of a series of self-instructional, computer-based learning modules for an introductory, undergraduate chemistry course. The student manual for this unit on Le Chatelier's principle includes objectives, prerequisites, pretest, instructions for executing the computer program, and…

Detection of creatinine enriched on a surface imprinted polystyrene film using FT-ATR-IR.

PubMed

Sreenivasan, K

2006-01-01

The surface of polystyrene (PS) was chemically modified by coating a thin layer of polyaniline (PANI) by oxidizing aniline using ammonium persulfate. Affinity sites for creatinine, a clinically relevant molecule, were created in the coated layer by adding creatinine as print molecules during the oxidation. The imprinted layer adsorbed creatinine was compared to non-imprinted surface reflecting the creation of creatinine-specific sites on the surface. The equilibrium was attained rapidly, indicating that a material of this kind is suitable for sensing applications. The adsorbed creatinine on the surface was detected using the technique of Fourier transform attenuated total internal reflection infra red spectroscopy (FT-ATR-IR). The results show that molecularly imprinted surface can enrich molecules of interest and the enriched molecules can be detected using FT-IR.

Understanding Radionuclide Interactions with Layered Materials

NASA Astrophysics Data System (ADS)

Wang, Y.

2015-12-01

Layered materials play an important role in nuclear waste management and environmental cleanup. Better understanding of radionuclide interactions with those materials is critical for engineering high-performance materials for various applications. This presentation will provide an overview on radionuclide interactions with two general categories of layered materials - cationic clays and anionic clays - from a perspective of nanopore confinement. Nanopores are widely present in layered materials, either as the interlayers or as inter-particle space. Nanopore confinement can significantly modify chemical reactions in those materials. This effect may cause the preferential enrichment of radionuclides in nanopores and therefore directly impact the mobility of the radionuclides. This effect also implies that conventional sorption measurements using disaggregated samples may not represent chemical conditions in actual systems. The control of material structures on ion exchange, surface complexation, and diffusion in layered materials will be systematically examined, and the related modeling approaches will be discussed. This work was performed at Sandia National Laboratories, which is a multiprogram laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the DOE under contract DE-AC04-94AL8500.

Sources and distribution of yttrium and rare earth elements in surface sediments from Tagus estuary, Portugal.

PubMed

Brito, Pedro; Prego, Ricardo; Mil-Homens, Mário; Caçador, Isabel; Caetano, Miguel

2018-04-15

The distribution and sources of yttrium and rare-earth elements (YREE) in surface sediments were studied on 78 samples collected in the Tagus estuary (SW Portugal, SW Europe). Yttrium and total REE contents ranged from 2.4 to 32mg·kg -1 and 18 to 210mg·kg -1 , respectively, and exhibited significant correlations with sediment grain-size, Al, Fe, Mg and Mn, suggesting a preferential association to fine-grained material (e.g. aluminosilicates but also Al hydroxides and Fe oxyhydroxides). The PAAS (Post-Archean Australian Shale) normalized patterns display three distinct YREE fractionation pattern groups along the Tagus estuary: a first group, characterized by medium to coarse-grained material, a depleted and almost flat PAAS-normalized pattern, with a positive anomaly of Eu, representing one of the lithogenic components; a second group, characterized mainly by fine-grained sediment, with higher shale-normalized ratios and an enrichment of LREE relative to HREE, associated with waste water treatment plant (WWTP) outfalls, located in the northern margin; and, a third group, of fine-grained material, marked by a significant enrichment of Y, a depletion of Ce and an enrichment of HREE over LREE, located near an inactive chemical-industrial complex (e.g. pyrite roast plant, chemical and phosphorous fertilizer industries), in the southern margin. The data allow the quantification of the YREE contents and its spatial distribution in the surface sediments of the Tagus estuary, identifying the main potential sources and confirming the use of rare earth elements as tracers of anthropogenic activities in highly hydrodynamic estuaries. Copyright © 2017 Elsevier B.V. All rights reserved.

Biocompatibility of Titania Nanotube Coatings Enriched with Silver Nanograins by Chemical Vapor Deposition

PubMed Central

Piszczek, Piotr; Lewandowska, Żaneta; Radtke, Aleksandra; Kozak, Wiesław; Sadowska, Beata; Szubka, Magdalena; Talik, Ewa; Fiori, Fabrizio

2017-01-01

Bioactivity investigations of titania nanotube (TNT) coatings enriched with silver nanograins (TNT/Ag) have been carried out. TNT/Ag nanocomposite materials were produced by combining the electrochemical anodization and chemical vapor deposition methods. Fabricated coatings were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The release effect of silver ions from TNT/Ag composites immersed in bodily fluids, has been studied using inductively coupled plasma mass spectrometry (ICP-MS). The metabolic activity assay (MTT) was applied to determine the L929 murine fibroblasts adhesion and proliferation on the surface of TNT/Ag coatings. Moreover, the results of immunoassays (using peripheral blood mononuclear cells—PBMCs isolated from rats) allowed the estimation of the immunological activity of TNT/Ag surface materials. Antibacterial activity of TNT/Ag coatings with different morphological and structural features was estimated against two Staphylococcus aureus strains (ATCC 29213 and H9). The TNT/Ag nanocomposite layers produced revealed a good biocompatibility promoting the fibroblast adhesion and proliferation. A desirable anti-biofilm activity against the S. aureus reference strain was mainly noticed for these TiO2 nanotube coatings, which contain dispersed Ag nanograins deposited on their surface. PMID:28914821

Mesoporous silica chips for selective enrichment and stabilization of low molecular weight proteome.

PubMed

Bouamrani, Ali; Hu, Ye; Tasciotti, Ennio; Li, Li; Chiappini, Ciro; Liu, Xuewu; Ferrari, Mauro

2010-02-01

The advanced properties of mesoporous silica have been demonstrated in applications, which include chemical sensing, filtration, catalysis, drug delivery and selective biomolecular uptake. These properties depend on the architectural, physical and chemical properties of the material, which in turn are determined by the processing parameters in evaporation-induced self-assembly. In this study, we introduce a combinatorial approach for the removal of the high molecular weight proteins and for the specific isolation and enrichment of low molecular weight species. This approach is based on mesoporous silica chips able to fractionate, selectively harvest and protect from enzymatic degradation, peptides and proteins present in complex human biological fluids. We present the characterization of the harvesting properties of a wide range of mesoporous chips using a library of peptides and proteins standard and their selectivity on the recovery of serum peptidome. Using MALDI-TOF-MS, we established the correlation between the harvesting specificity and the physicochemical properties of mesoporous silica surfaces. The introduction of this mesoporous material with fine controlled properties will provide a powerful platform for proteomics application offering a rapid and efficient methodology for low molecular weight biomarker discovery.

The Isotopic Record From Monogenetic Seamounts: Insights Into Recycling Time Scales In The Upper Mantle

NASA Astrophysics Data System (ADS)

Madrigal Quesada, P.; Gazel, E.

2017-12-01

Monogenetic seamounts related to non-plume intraplate magmatism provide a window into the composition of upper mantle heterogeneities, nevertheless, the origin of these heterogeneities are still not well constrained. Radiogenic isotopes (Sr-Nd-Pb) from present-day ocean island basalts (OIB) produced by this type of magmatism can help establish the source compositions of these chemically and isotopically enriched reservoirs. Here we present evidence that suggests that a highly enriched mantle reservoir can originate from OIB-type subducted material that gets incorporated and stirred throughout the upper mantle. We explore this hypothesis using data from non-plume related OIB volcanism; focusing on isolated monogenetic seamounts with no apparent age progression and interpreted to be related to either plate flexure, shear driven convection and/or edge convection. The isotopic record compiled, added to new results obtained from accreted petit-spot seamounts from Santa Elena Peninsula in Costa Rica, suggest that a highly radiogenic mantle reservoir originated from recycled seamount materials can be formed in a shorter time scale than ancient subducted oceanic crust (>1 Ga), thought to be the forming agent of the HIMU mantle "flavor" found in some of these small-scale seamounts. The implications of these results entail that the recycling of already enriched materials in short time scales and in restricted depths within the Upper Mantle may play an important role in the source of OIBs (plume and non-plume related), as well as, the most enriched suites of EMORBs.

An r-process enhanced star in the dwarf galaxy Tucana III

DOE PAGES

Hansen, T. T.; Simon, J. D.; Marshall, J. L.; ...

2017-03-20

Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly discovered ultra-faint dwarf galaxy candidate Tucana III. Because it is particularly bright for a star in an ultra-faint Milky Way (MW) satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DES J235532.66–593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the r-process and can be classified as an r-I star. DES J235532 is the first r-Imore » star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain r-process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with r-I and r-II stars found in other dwarf galaxies and in the MW halo suggests a common astrophysical origin for the neutron-capture elements seen in all r-process enhanced stars. Furthermore, we explore both internal and external scenarios for the r-process enrichment of Tuc III and show that with abundance patterns for additional stars, it should be possible to distinguish between them.« less

An r-process enhanced star in the dwarf galaxy Tucana III

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, T. T.; Simon, J. D.; Marshall, J. L.

Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly discovered ultra-faint dwarf galaxy candidate Tucana III. Because it is particularly bright for a star in an ultra-faint Milky Way (MW) satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DES J235532.66–593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the r-process and can be classified as an r-I star. DES J235532 is the first r-Imore » star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain r-process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with r-I and r-II stars found in other dwarf galaxies and in the MW halo suggests a common astrophysical origin for the neutron-capture elements seen in all r-process enhanced stars. Furthermore, we explore both internal and external scenarios for the r-process enrichment of Tuc III and show that with abundance patterns for additional stars, it should be possible to distinguish between them.« less

ToO Galactic Nova -- Michelle ``Quick Response''

NASA Astrophysics Data System (ADS)

Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

2006-08-01

Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

Synoptic Mid-IR Spectra ToO Novae

NASA Astrophysics Data System (ADS)

Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

2007-02-01

Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

Geochemical evidence of chemical and physical weathering of mine waste downriver from the New Idria Mercury Mine, San Benito County, California

NASA Astrophysics Data System (ADS)

Sharma, R. K.; Weinman, B.

2014-12-01

Soil, river bank, and sediment samples were collected from Panoache Creek's mine tailings and its drainages in the Mendota Pool area of California's Central Valley. The samples were collected in order to understand the transport mechanisms of mercury and other heavy metals from the abandoned New Idria Mercury Mine (NIMM) in San Banito County, CA. It is generally thought that materials weathered from the NIMM site flow down gradient into the San Carlos Creek, which then joins Silver Creek and Panoche Creek, before finally ending up in the Valley's Mendota pool and San Joaquin River (SJR). While we know that factors like geology, anthropogenic activities, and weathering can accelerate heavy metal accumulation at downgradient reaches (Chakravarty and Patgiri, 2009), it is unclear how this part of the SJR has responded to the mine's abandonment since the 1970s. To investigate how mercury and other heavy metals are weathering and being transported through this portion of the SJR drainage, gains and losses using "enrichment factors" (EF) were calculated and compared along a gradient downstream. Overall, EF of fine and bank sediments show Hg is being enriched and stored within bank sediments. For example, Hg in banks sediments are up to 5% enriched compared to the bed sediments. There is also an enrichment gain trending downstream, as sediments settling in the Mendota pool have comparatively higher EF for Hg (0.94 ppm to 6.91 ppm) relative to background concentrations. Along with other geochemical indices, which can be used to more highly resolve exactly how mine contaminants like Hg are chemically and physically being weathered, (i.e., Igeo, PLI, and CIA) the overall enrichment trend is interpreted to be the physical transport of erosion material during runoff events from the stream banks of SJR tributaries. This interpretation is also supported by depleted Sr and enriched Rb/Sr ratios, which further support physical transport as a dominating factor in contaminant enrichment along the banks of the catchment area. Combined with general trends of increasing Igeo, PLI values, and generally low CIA indices, results support Hg weathering predominantly being controlled by a combination of physical weathering, anthropogenic activities, and bank erosion, that lead to Hg mobilization and transport to downstream areas.

Surface engineering on mesoporous silica chips for enriching low molecular weight phosphorylated proteins

NASA Astrophysics Data System (ADS)

Hu, Ye; Peng, Yang; Lin, Kevin; Shen, Haifa; Brousseau, Louis C., III; Sakamoto, Jason; Sun, Tong; Ferrari, Mauro

2011-02-01

Phosphorylated peptides and proteins play an important role in normal cellular activities, e.g., gene expression, mitosis, differentiation, proliferation, and apoptosis, as well as tumor initiation, progression and metastasis. However, technical hurdles hinder the use of common fractionation methods to capture phosphopeptides from complex biological fluids such as human sera. Herein, we present the development of a dual strategy material that offers enhanced capture of low molecular weight phosphoproteins: mesoporous silica thin films with precisely engineered pore sizes that sterically select for molecular size combined with chemically selective surface modifications (i.e. Ga3+, Ti4+ and Zr4+) that target phosphoroproteins. These materials provide high reproducibility (CV = 18%) and increase the stability of the captured proteins by excluding degrading enzymes, such as trypsin. The chemical and physical properties of the composite mesoporous thin films were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and ellipsometry. Using mass spectroscopy and biostatistics analysis, the enrichment efficiency of different metal ions immobilized on mesoporous silica chips was investigated. The novel technology reported provides a platform capable of efficiently profiling the serum proteome for biomarker discovery, forensic sampling, and routine diagnostic applications.Phosphorylated peptides and proteins play an important role in normal cellular activities, e.g., gene expression, mitosis, differentiation, proliferation, and apoptosis, as well as tumor initiation, progression and metastasis. However, technical hurdles hinder the use of common fractionation methods to capture phosphopeptides from complex biological fluids such as human sera. Herein, we present the development of a dual strategy material that offers enhanced capture of low molecular weight phosphoproteins: mesoporous silica thin films with precisely engineered pore sizes that sterically select for molecular size combined with chemically selective surface modifications (i.e. Ga3+, Ti4+ and Zr4+) that target phosphoroproteins. These materials provide high reproducibility (CV = 18%) and increase the stability of the captured proteins by excluding degrading enzymes, such as trypsin. The chemical and physical properties of the composite mesoporous thin films were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and ellipsometry. Using mass spectroscopy and biostatistics analysis, the enrichment efficiency of different metal ions immobilized on mesoporous silica chips was investigated. The novel technology reported provides a platform capable of efficiently profiling the serum proteome for biomarker discovery, forensic sampling, and routine diagnostic applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c0nr00720j

Enrichment and characterization of ferritin for nanomaterial applications

NASA Astrophysics Data System (ADS)

Ghirlando, Rodolfo; Mutskova, Radina; Schwartz, Chad

2016-01-01

Ferritin is a ubiquitous iron storage protein utilized as a nanomaterial for labeling biomolecules and nanoparticle construction. Commercially available preparations of horse spleen ferritin, widely used as a starting material, contain a distribution of ferritins with different iron loads. We describe a detailed approach to the enrichment of differentially loaded ferritin molecules by common biophysical techniques such as size exclusion chromatography and preparative ultracentrifugation, and characterize these preparations by dynamic light scattering, and analytical ultracentrifugation. We demonstrate a combination of methods to standardize an approach for determining the chemical load of nearly any particle, including nanoparticles and metal colloids. Purification and characterization of iron content in monodisperse ferritin species is particularly critical for several applications in nanomaterial science.

Readiness Review of BWXT for Fabrication of AGR-5/6/7 TRISO Particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, Douglas William; Sharp, Michelle Tracy

2016-02-01

INL readiness review assessment of BWXT readiness to commence fabrication of low-enriched TRISO coated fuel particles for the AGR-5/6/7 irradiation experiments. BWXT self-identified equipment issues preventing operation. INL identified two findings. The first was that disposition codes had not been assigned and documented on BWXT forms to ensure that off-specification materials could not be used in the fabrication of TRISO particles. The second was that chemical purity specifications were not reliably passed on to chemical suppliers, which resulted in the receipt of one acetylene cylinder with suspect impurity levels.

Characterization of Size-Fractionated Airborne Particles Inside an Electronic Waste Recycling Facility and Acute Toxicity Testing in Mice.

PubMed

Kim, Yong Ho; Wyrzykowska-Ceradini, Barbara; Touati, Abderrahmane; Krantz, Q Todd; Dye, Janice A; Linak, William P; Gullett, Brian; Gilmour, M Ian

2015-10-06

Disposal of electronic waste (e-waste) in landfills, incinerators, or at rudimentary recycling sites can lead to the release of toxic chemicals into the environment and increased health risks. Developing e-waste recycling technologies at commercial facilities can reduce the release of toxic chemicals and efficiently recover valuable materials. While these e-waste operations represent a vast improvement over previous approaches, little is known about environmental releases, workplace exposures, and potential health impacts. In this study, airborne particulate matter (PM) was measured at various locations within a modern U.S.-based e-waste recycling facility that utilized mechanical processing. In addition, composite size fractionated PM (coarse, fine and ultrafine) samples were collected, extracted, chemically analyzed, and given by oropharyngeal aspiration to mice or cultured with lung slices for lung toxicity tests. Indoor total PM concentrations measured during the study ranged from 220 to 1200 μg/m(3). In general, the coarse PM (2.5-10 μm) was 3-4 times more abundant than fine/ultrafine PM (<2.5 μm). The coarse PM contained higher levels of Ni, Pb, and Zn (up to 6.8 times) compared to the fine (0.1-2.5 μm) and ultrafine (<0.1 μm) PM. Compared to coarse PM measurements from a regional near-roadway study, Pb and Ni were enriched 170 and 20 times, respectively, in the indoor PM, with other significant enrichments (>10 times) observed for Zn and Sb, modest enrichments (>5 times) for Cu and Sr, and minor enrichments (>2 times) for Cr, Cd, Mn, Ca, Fe, and Ba. Negligible enrichment (<2 times) or depletion (<1 time) were observed for Al, Mg, Ti, Si, and V. The coarse PM fraction elicited significant pro-inflammatory responses in the mouse lung at 24 h postexposure compared to the fine and ultrafine PM, and similar toxicity outcomes were observed in the lung slice model. We conclude that exposure to coarse PM from the facility caused substantial inflammation in the mouse lung and enrichment of these metals compared to levels normally present in the ambient PM could be of potential health concern.

Interplay between materials and microfluidics

NASA Astrophysics Data System (ADS)

Hou, Xu; Zhang, Yu Shrike; Santiago, Grissel Trujillo-De; Alvarez, Mario Moisés; Ribas, João; Jonas, Steven J.; Weiss, Paul S.; Andrews, Anne M.; Aizenberg, Joanna; Khademhosseini, Ali

2017-04-01

Developments in the field of microfluidics have triggered technological revolutions in many disciplines, including chemical synthesis, electronics, diagnostics, single-cell analysis, micro- and nanofabrication, and pharmaceutics. In many of these areas, rapid growth is driven by the increasing synergy between fundamental materials development and new microfluidic capabilities. In this Review, we critically evaluate both how recent advances in materials fabrication have expanded the frontiers of microfluidic platforms and how the improved microfluidic capabilities are, in turn, furthering materials design. We discuss how various inorganic and organic materials enable the fabrication of systems with advanced mechanical, optical, chemical, electrical and biointerfacial properties — in particular, when these materials are combined into new hybrids and modular configurations. The increasing sophistication of microfluidic techniques has also expanded the range of resources available for the fabrication of new materials, including particles and fibres with specific functionalities, 3D (bio)printed composites and organoids. Together, these advances lead to complex, multifunctional systems, which have many interesting potential applications, especially in the biomedical and bioengineering domains. Future exploration of the interactions between materials science and microfluidics will continue to enrich the diversity of applications across engineering as well as the physical and biomedical sciences.

Characterization of airborne particles at a high-btu coal-gasification pilot plant.

PubMed

Davidson, C I; Santhanam, S; Stetter, J R; Flotard, R D; Gebert, E

1982-12-01

Airborne particles in fugitive emissions have been measured at a slagging fixed-bed coal-gasification pilot plant using lignite. Sampling was conducted during shutdown operations and opening of the gasifier following an aborted startup. Aerosol collected with a Sierra high-volume impactor was subjected to analysis by gas chromatography, mass spectrometry, and scanning electron microscopy; aerosol collected with an Andersen low-volume impactor was subjected to flameless atomic absorption analysis. The data show that the bulk of the trace organic material is associated with small particles: these data are similar to data on ambient air reported in the literature. Particle morphologies resemble those of fly ash from coal combustion, including smooth spheres, vesicular spheres, and crystalline material. Trace element size distributions are bimodal and resemble data for ambient air. Pb-containing particles are generally submicron, while particles containing Al, Fe, and other crustal species are mostly of supermicron size. Aluminum-based aerosol enrichment factors calculated from the lignite composition show that the composition of the aerosol resembles that of the coal, with the exception of modest enrichments of Mg, Na, As, and Pb in the submicron size range. Aerosol enrichment factors based on the earth's crustal composition are somewhat greater than those based on coal composition for several elements, suggesting potential errors in using crustal enrichment data to investigate chemical fractionation during aerosol formation.

Editor's Highlight: Application of Gene Set Enrichment Analysis for Identification of Chemically Induced, Biologically Relevant Transcriptomic Networks and Potential Utilization in Human Health Risk Assessment.

PubMed

Dean, Jeffry L; Zhao, Q Jay; Lambert, Jason C; Hawkins, Belinda S; Thomas, Russell S; Wesselkamper, Scott C

2017-05-01

The rate of new chemical development in commerce combined with a paucity of toxicity data for legacy chemicals presents a unique challenge for human health risk assessment. There is a clear need to develop new technologies and incorporate novel data streams to more efficiently inform derivation of toxicity values. One avenue of exploitation lies in the field of transcriptomics and the application of gene expression analysis to characterize biological responses to chemical exposures. In this context, gene set enrichment analysis (GSEA) was employed to evaluate tissue-specific, dose-response gene expression data generated following exposure to multiple chemicals for various durations. Patterns of transcriptional enrichment were evident across time and with increasing dose, and coordinated enrichment plausibly linked to the etiology of the biological responses was observed. GSEA was able to capture both transient and sustained transcriptional enrichment events facilitating differentiation between adaptive versus longer term molecular responses. When combined with benchmark dose (BMD) modeling of gene expression data from key drivers of biological enrichment, GSEA facilitated characterization of dose ranges required for enrichment of biologically relevant molecular signaling pathways, and promoted comparison of the activation dose ranges required for individual pathways. Median transcriptional BMD values were calculated for the most sensitive enriched pathway as well as the overall median BMD value for key gene members of significantly enriched pathways, and both were observed to be good estimates of the most sensitive apical endpoint BMD value. Together, these efforts support the application of GSEA to qualitative and quantitative human health risk assessment. Published by Oxford University Press on behalf of the Society of Toxicology 2017. This work is written by US Government employees and is in the public domain in the US.

Determination of niobium in rocks, ores and alloys by atomic-absorption spectrophotometry.

PubMed

Husler, J

1972-07-01

Niobium, in concentrations as low as 0.02% Nb(2)O(5), is determined in a variety of materials without separation or enrichment. Chemical and ionization interferences are controlled, and sensitivity is increased, by maintaining the iron, aluminium, hydrofluoric acid and potassium content within certain broad concentration limits. There is close agreement with the results of analyses by emission spectrographic, electron microprobe and X-ray fluorescence methods.

A mineralogical study in contrasts: highly mineralized whale rostrum and human enamel

NASA Astrophysics Data System (ADS)

Li, Zhen; Ai-Jawad, Maisoon; Siddiqui, Samera; Pasteris, Jill D.

2015-11-01

The outermost enamel of the human tooth and the rostrum of the whale Mesoplodon densirostris are two highly mineralized tissues that contain over 95 wt.% mineral, i.e., bioapatite. However, the same mineral type (carbonated hydroxylapatite) does not yield the same material properties, as revealed by Raman spectroscopy, scanning electron microscopy, electron microprobe analysis, and synchrotron X-ray diffraction analysis. Overall, the outermost enamel of a tooth has more homogeneous physical and chemical features than the rostrum. Chemical comparison of rostrum and enamel shows bioapatite in the rostrum to be enriched in Na, Mg, CO3, and S, whereas the outermost enamel shows only a slightly enriched Cl concentration. Morphologically, mineral rods (at tens of μm scale), crystallites and prisms (at μm and sub-μm scale), and platelets (at tens of nm scale) all demonstrate less organized texture in the rostrum than in enamel. Such contrasts between two mineralized tissues suggest distinct pathways of biomineralization, e.g., the nature of the equilibrium between mineral and body fluid. This study illustrates the remarkable flexibility of the apatite mineral structure to match its chemical and physical properties to specific biological needs within the same animal or between species.

[Effects of Different Modifier Concentrations on Lead-Zinc Tolerance, Subcellular Distribution and Chemical Forms for Four Kinds of Woody Plants].

PubMed

Chen, Yong-hua; Zhang, Fu-yun; Wu, Xiao-fu; Liang, Xi; Yuan, Si-wen

2015-10-01

Four kinds of lead-zinc tolerant woody plants: Nerium oleander, Koelreuteria paniculata, Paulownia and Boehmeria were used as materials to estimate their enrichment and transferable capacity of lead (Pb) and zinc (Zn) and analyze the subcellular distribution and chemical speciation of Zn and Ph in different parts of plants, under different modifier concentrations (CK group: 100% lead-zinc slag plus a small amount of phosphate fertilizer, improved one: 85% of lead-zinc slag ± 10% peat ± 5% bacterial manure plus a small amount of phosphate fertilizer, improved two: 75% lead-zinc slag ± 20% peat ± 5% bacterial manure ± a small amount of phosphate). Results showed that: (1) The content of Pb, Zn in matrix after planting four kinds of plants was lower than before, no significant difference between improved one and improved two of Nerium oleander and Boehmeria was found, but improved two was better than improved one of Paulownia, while improved one was better than improved two of Koelreuteria paniculata; Four plants had relatively low aboveground enrichment coefficient of Pb and Zn, but had a high transfer coefficient, showed that the appropriate modifier concentration was able to improve the Pb and Zn enrichment and transfer ability of plants. (2) In subcellular distribution, most of Pb and Zn were distributed in plant cell wall components and soluble components while the distribution in cell organelles such as mitochondria, chloroplasts and nucleus component were less. Compared with CK group, two improved group made soluble components of the cell walls of Pb fixation and retention of zinc role in the enhancement. (3) As for the chemical forms of Pb and Zn in plants, the main chemical forms of Pb were hydrochloric acid, sodium chloride and ethanol extractable forms, while other chemical form contents were few, the main chemical forms of Zn were different based on plant type. Compared with CK group, the proportion of the active Pb chemical form in different plant parts decreased in two improved groups, while the proportion of strong activity chemical forms increased; two improved groups led strong activity Zn chemical form of root increased, while strong activity Zn chemical form of aboveground decreased.

Impact of carbonaceous materials in soil on the transport of soil-bound PAHs during rainfall-runoff events.

PubMed

Luo, Xiaolin; Zheng, Yi; Wu, Bin; Lin, Zhongrong; Han, Feng; Zhang, Wei; Wang, Xuejun

2013-11-01

Polycyclic Aromatic Hydrocarbons (PAHs) transported from contaminated soils by surface runoff pose significant risk for aquatic ecosystems. Based on a rainfall-runoff simulation experiment, this study investigated the impact of carbonaceous materials (CMs) in soil, identified by organic petrology analysis, on the transport of soil-bound PAHs under rainfall conditions. The hypothesis that composition of soil organic matter significantly impacts the enrichment and transport of PAHs was proved. CMs in soil, varying significantly in content, mobility and adsorption capacity, act differently on the transport of PAHs. Anthropogenic CMs like black carbon (BC) largely control the transport, as PAHs may be preferentially attached to them. Eventually, this study led to a rethink of the traditional enrichment theory. An important implication is that CMs in soil have to be explicitly considered to appropriately model the nonpoint source pollution of PAHs (possibly other hydrophobic chemicals as well) and assess its environmental risk. Copyright © 2013 Elsevier Ltd. All rights reserved.

Redox exchange induced MnO2 nanoparticle enrichment in poly(3,4-ethylenedioxythiophene) nanowires for electrochemical energy storage.

PubMed

Liu, Ran; Duay, Jonathon; Lee, Sang Bok

2010-07-27

MnO2 nanoparticle enriched poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires are fabricated by simply soaking the PEDOT nanowires in potassium permanganate (KMnO4) solution. The structures of these MnO2 nanoparticle enriched PEDOT nanowires are characterized by SEM and TEM, which show that the MnO2 nanoparticles have uniform sizes and are finely dispersed in the PEDOT matrix. The chemical constituents and bonding of these composite nanowires are characterized by energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and infrared spectroscopy, which indicate that the formation and dispersion of these MnO2 nanoparticles into the nanoscale pores of the PEDOT nanowires are most likely triggered by the reduction of KMnO4 via the redox exchange of permanganate ions with the functional group on PEDOT. Varying the concentrations of KMnO4 and the reaction time controls the loading amount and size of the MnO2 nanoparticles. Cyclic voltammetry and galvanostatic charge-discharge are used to characterize the electrochemical properties of these MnO2 nanoparticle loaded PEDOT nanowires. Due to their extremely high exposed surface area with nanosizes, the pristine MnO2 nanoparticles in these MnO2 nanoparticle enriched PEDOT nanowires show very high specific capacitance (410 F/g) as the supercapacitor electrode materials as well as high Li+ storage capacity (300 mAh/g) as cathode materials of Li ion battery, which boost the energy storage capacity of PEDOT nanowires to 4 times without causing excessive volume expansion in the polymer. The highly conductive and porous PEDOT matrix facilitates fast charge/discharge of the MnO2 nanoparticles and prevents them from agglomerating. These synergic properties enable the MnO2 nanoparticle enriched PEDOT nanowires to be promising electrode materials for supercapacitors and lithium ion batteries.

Litter decomposition over broad spatial and long time scales investigated by advanced solid-state NMR: insight into effects of climate, litter quality, and time

NASA Astrophysics Data System (ADS)

Mao, J.; Chen, N.; Harmon, M. E.; Li, Y.; Cao, X.; Chappell, M.

2012-12-01

Advanced 13C solid-state NMR techniques were employed to study the chemical structural changes of litter decomposition across broad spatial and long time scales. The fresh and decomposed litter samples of four species (Acer saccharum (ACSA), Drypetes glauca (DRGL), Pinus resinosa (PIRE), and Thuja plicata (THPL)) incubated for up to 10 years at four sites under different climatic conditions (from Arctic to tropical forest) were examined. Decomposition generally led to an enrichment of cutin and surface wax materials, and a depletion of carbohydrates causing overall composition to become more similar compared with original litters. However, the changes of main constituents in the four litters were inconsistent with the four litters following different pathways of decomposition at the same site. As decomposition proceeded, waxy materials decreased at the early stage and then gradually increased in PIRE; DRGL showed a significant depletion of lignin and tannin while the changes of lignin and tannin were relative small and inconsistent for ACSA and THPL. In addition, the NCH groups, which could be associated with either fungal cell wall chitin or bacterial wall petidoglycan, were enriched in all litters except THPL. Contrary to the classic lignin-enrichment hypothesis, DRGL with low-quality C substrate had the highest degree of composition changes. Furthermore, some samples had more "advanced" compositional changes in the intermediate stage of decomposition than in the highly-decomposed stage. This pattern might be attributed to the formation of new cross-linking structures, that rendered substrates more complex and difficult for enzymes to attack. Finally, litter quality overrode climate and time factors as a control of long-term changes of chemical composition.

Effect of CO2 levels on nutrient content of lettuce and radish.

PubMed

McKeehen, J D; Smart, D J; Mackowiak, C L; Wheeler, R M; Nielsen, S S

1996-01-01

Atmospheric carbon-dioxide enrichment is known to affect the yield of lettuce and radish grown in controlled environments, but little is known about CO2 enrichment effects on the chemical composition of lettuce and radish. These crops are useful model systems for a Controlled Ecological Life-Support System (CELSS), largely because of their relatively short production cycles. Lettuce (Lactuca sativa L.) cultivar 'Waldmann's Green' and radish (Raphanus sativus L.) cultivar 'Giant White Globe' were grown both in the field and in controlled environments, where hydroponic nutrient solution, light, and temperature were regulated, and where CO2 levels were controlled at 400, 1000, 5000, or 10,000 ppm. Plants were harvested at maturity, dried, and analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate N, free sugars, starch, total dietary fiber, and minerals. Total N, protein N, nonprotein N (NPN), and nitrate N generally increased for radish roots and lettuce leaves when grown under growth chamber conditions compared to field conditions. The nitrate-N level of lettuce leaves, as a percentage of total NPN, decreased with increasing levels of CO2 enrichment. The ash content of radish roots and of radish and lettuce leaves decreased with increasing levels of CO2 enrichment. The levels of certain minerals differed between field- and chamber-grown materials, including changes in the calcium (Ca) and phosphorus (P) contents of radish and lettuce leaves, resulting in reduced Ca/P ratio for chamber-grown materials. The free-sugar contents were similar between the field and chamber-grown lettuce leaves, but total dietary fiber content was much higher in the field-grown plant material. The starch content of growth-chamber lettuce increased with CO2 level.

Effect of CO_2 levels on nutrient content of lettuce and radish

NASA Astrophysics Data System (ADS)

McKeehen, J. D.; Smart, D. J.; Mackowiak, C. L.; Wheeler, R. M.; Nielsen, S. S.

Atmospheric carbon-dioxide enrichment is known to affect the yield of lettuce and radish grown in controlled environments, but little is known about CO_2 enrichment effects on the chemical composition of lettuce and radish. These crops are useful model systems for a Controlled Ecological Life-Support System (CELSS), largely because of their relatively short production cycles. Lettuce (Lactuca sativa L.) cultivar `Waldmann's Green' and radish (Raphanus sativus L.) cultivar `Giant White Globe' were grown both in the field and in controlled environments, where hydroponic nutrient solution, light, and temperature were regulated, and where CO_2 levels were controlled at 400, 1000, 5000, or 10,000 ppm. Plants were harvested at maturity, dried, and analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate N, free sugars, starch, total dietary fiber, and minerals. Total N, protein N, nonprotein N (NPN), and nitrate N generally increased for radish roots and lettuce leaves when grown under growth chamber conditions compared to field conditions. The nitrate-N level of lettuce leaves, as a percentage of total NPN, decreased with increasing levels of CO_2 enrichment. The ash content of radish roots and of radish and lettuce leaves decreased with increasing levels of CO_2 enrichment. The levels of certain minerals differed between field- and chamber-grown materials, including changes in the calcium (Ca) and phosphorus (P) contents of radish roots and lettuce leaves, resulting in reduced Ca/P ratio for chamber-grown materials. The free-sugar contents were similar between the field and chamber-grown lettuce leaves, but total dietary fiber content was much higher in the field-grown plant material. The starch content of growth-chamber lettuce increased with CO_2 level.

Effect of CO2 levels on nutrient content of lettuce and radish

NASA Technical Reports Server (NTRS)

McKeehen, J. D.; Smart, D. J.; Mackowiak, C. L.; Wheeler, R. M.; Nielsen, S. S.; Mitchell, C. A. (Principal Investigator)

1996-01-01

Atmospheric carbon-dioxide enrichment is known to affect the yield of lettuce and radish grown in controlled environments, but little is known about CO2 enrichment effects on the chemical composition of lettuce and radish. These crops are useful model systems for a Controlled Ecological Life-Support System (CELSS), largely because of their relatively short production cycles. Lettuce (Lactuca sativa L.) cultivar 'Waldmann's Green' and radish (Raphanus sativus L.) cultivar 'Giant White Globe' were grown both in the field and in controlled environments, where hydroponic nutrient solution, light, and temperature were regulated, and where CO2 levels were controlled at 400, 1000, 5000, or 10,000 ppm. Plants were harvested at maturity, dried, and analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate N, free sugars, starch, total dietary fiber, and minerals. Total N, protein N, nonprotein N (NPN), and nitrate N generally increased for radish roots and lettuce leaves when grown under growth chamber conditions compared to field conditions. The nitrate-N level of lettuce leaves, as a percentage of total NPN, decreased with increasing levels of CO2 enrichment. The ash content of radish roots and of radish and lettuce leaves decreased with increasing levels of CO2 enrichment. The levels of certain minerals differed between field- and chamber-grown materials, including changes in the calcium (Ca) and phosphorus (P) contents of radish and lettuce leaves, resulting in reduced Ca/P ratio for chamber-grown materials. The free-sugar contents were similar between the field and chamber-grown lettuce leaves, but total dietary fiber content was much higher in the field-grown plant material. The starch content of growth-chamber lettuce increased with CO2 level.

Cometary Materials Originating from Interstellar Ices: Clues from Laboratory Experiments

NASA Astrophysics Data System (ADS)

Fresneau, A.; Abou Mrad, N.; d'Hendecourt, L. LS; Duvernay, F.; Flandinet, L.; Orthous-Daunay, F.-R.; Vuitton, V.; Thissen, R.; Chiavassa, T.; Danger, G.

2017-03-01

We use laboratory experiments to derive information on the chemistry occurring during the evolution of astrophysical ices from dense molecular clouds to interplanetary objects. Through a new strategy that consists of coupling very high resolution mass spectrometry and infrared spectroscopy (FT-IR), we investigate the molecular content of the organic residues synthesized from different initial ice compositions. We also obtain information on the evolution of the soluble part of the residues after their over-irradiation. The results give insight into the role of water ice as a trapping and diluting agent during the chemical evolution. They also give information about the importance of the amount of ammonia in such ices, particularly regarding its competition with the carbon chemistry. All of these results allow us to build a first mapping of the evolution of soluble organic matter based on its chemical and physical history. Furthermore, our results suggest that interstellar ices should lead to organic materials enriched in heteroatoms that present similarities with cometary materials but strongly differ from meteoritic organic material, especially in their C/N ratios.

77 FR 60482 - Regulatory Guide 5.67, Material Control and Accounting for Uranium Enrichment Facilities...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-03

... Accounting for Uranium Enrichment Facilities Authorized To Produce Special Nuclear Material of Low Strategic... Accounting for Uranium Enrichment Facilities Authorized to Produce Special Nuclear Material of Low Strategic... INFORMATION CONTACT: Glenn Tuttle, Office of Nuclear Material Safety and Safeguards, Division of Fuel Cycle...

Environmental Impacts Of Zirab Coal Washing Plant, Mazandaran, Iran

NASA Astrophysics Data System (ADS)

Moore, F.; Esmaeili, A.

2009-04-01

Extraction and beneficiation operations associated with coal mining increase the rate of chemical reaction of waste material to air and water media. Zirab coal washing plant is located on the bank of the Cherat stream in Mazandaran province, Iran. coal Mined from central Alborz coalfield mines is not suitable for use in Iranian Steel Corporation. Hence, coal ash content is reduced by physical and chemical processes in this plant. These processes leave a large quantity of liquid and solid wastes that accumulate in waste dump and tailing dam. sediment and water samples taken from Sheshrudbar and Cherat streams and also from Talar river show high concentration of Cd, Mo and As in water samples of coal washing plant and the associated drainage. Eh-pH diagrams revealed the chemical species of elements in water. The enrichment factor and geoaccumulation index show that Cd, Hg, Mo and V are enriched in bottom sediments of the coal washing plant and decrease with increasing distance from the plant. Sequential extraction analysis Results of three sediment samples of Cherat stream show that silicate bound is the major phase in samples taken before and after the plant, but adjacent to the plant, organic bound is dominant. The high concentration of Cd and Mo in the water soluble phase, is noticeable and may result in high mobility and bioavailability of these elements. Mann-Whitney and Wilcoxon tests on six samples, before and after the coal washing plant support the obtained results. Keywords: Zirab; coal washing plant; Sequential extraction analysis; Mann-whitney; Wilcoxon; Enrichment factor; Geoaccumulation index.

N-C isotopic investigation of a zeolite-amended agricultural field

NASA Astrophysics Data System (ADS)

Ferretti, Giacomo; Natali, Claudio; Faccini, Barbara; Di Giuseppe, Dario; Bianchini, Gianluca; Coltorti, Massimo

2016-04-01

In this study, a C and N isotopic investigation in the soil-plant system of the ZeoLIFE project experimental field have been carried out. Since many years, natural and NH4-enriched zeolites have been used as soil amendant in agricultural context in order to reduce N losses, increase NUE (Nitrogen Use Efficiency) and crop yield. Nevertheless up to now there are no studies that, using the stable isotopes approach, highlighted the interaction between zeolites and plants in agricultural systems. The main aims of this study is to verify if natural zeolites amendment can enhance chemical fertilization efficiency and if N transfer from NH4-enriched zeolites to plants really occurs. Plants grown following traditional cultivation methods (with no zeolite addition) and plants grown on soils amended with natural and NH4-enriched zeolites (the latter obtained after mixing with pig-slurry with a very high 15N) were compared for two cultivation cycles (maize and wheat). As widely known, plants grown under conventional farming systems (use of chemical fertilizers as urea) and plants grown under organic farming can be discriminated by the isotopic signatures of plant tissues. For both years the main results of the study reveals that plants grown on plots amended with natural zeolites generally have their nitrogen isotopic signature more similar to that of the chemical fertilizers employed during the cultivation with respect to the plants cultivated in the non-amended plot. This suggests an enhanced N uptake by the plant from this specific N source with respect to the non-amended plot. On the other hand, plants grown on NH4-enriched zeolites registered a higher 15N, approaching the pig-slurry isotopic signature, confirming that this material can constitute an N pool for plants at least for two cultivation cycles. The distinct agricultural practices seem to be reflected in the plant physiology as recorded by the carbon discrimination factor (13C) which generally increases in plots amended with natural zeolites indicating better water/nutrient conditions. At similar N availability it seems that plant prefer to use natural N from pig slurry instead of using that coming from chemical fertilizers.

Controlling factors of soil selenium distribution in a watershed in Se-enriched and longevity region of South China.

PubMed

Shao, Ya; Cai, Chongfa; Zhang, Haitao; Fu, Wei; Zhong, Xuemei; Tang, Shen

2018-05-10

Selenium (Se) is an essential nutritional element for human beings. Many studies have been conducted on concentration and distribution patterns of soil Se in low Se, Se-enriched, and selenosis areas; however, soil Se has not been systematically studied in a watershed, especially in Se-enriched longevity region and karst area in South China. This study is carried out to explore the controlling factors of Se-enriched soils in Baishou river tributary watershed, where soils are Se-enriched, and local people have the phenomenon of longevity. The area-weighted average rock Se concentration in the watershed is 0.054 mg/kg, and there are no significant differences in rock Se concentration between different strata and between different lithological rocks. The area-weighted average concentration of Se in soils (0-20 cm) is 0.80 mg/kg, and the soil Se concentration is of high level in the watershed. Soil Se concentration decreases from upstream to downstream in the watershed, and significantly correlated with elevation. Climate is the main factor causing high content of soil Se in the watershed which lacks black rock series. The difference of clastic and carbonate parent materials in soil forming process and the physical and chemical properties (pH, OM, etc.) are the main reasons for the spatial variation of Se distribution in the watershed. The research will be beneficial to the development and utilization of Se-enriched soil in Se-enriched area.

Recent advances in chemical functionalization of nanoparticles with biomolecules for analytical applications.

PubMed

Oh, Ju-Hwan; Park, Do Hyun; Joo, Jang Ho; Lee, Jae-Seung

2015-11-01

The recent synthetic development of a variety of nanoparticles has led to their widespread application in diagnostics and therapeutics. In particular, the controlled size and shape of nanoparticles precisely determine their unique chemical and physical properties, which is highly attractive for accurate analysis of given systems. In addition to efforts toward controlling the synthesis and properties of nanoparticles, the surface functionalization of nanoparticles with biomolecules has been intensively investigated since the mid-1990s. The complicated yet programmable properties of biomolecules have proved to substantially enhance and enrich the novel functions of nanoparticles to achieve "smart" nanoparticle materials. In this review, the advances in chemical functionalization of four types of representative nanoparticle with DNA and protein molecules in the past five years are critically reviewed, and their future trends are predicted.

Nuclear energy in Europe: uranium flow modeling and fuel cycle scenario trade-offs from a sustainability perspective.

PubMed

Tendall, Danielle M; Binder, Claudia R

2011-03-15

The European nuclear fuel cycle (covering the EU-27, Switzerland and Ukraine) was modeled using material flow analysis (MFA).The analysis was based on publicly available data from nuclear energy agencies and industries, national trade offices, and nongovernmental organizations. Military uranium was not considered due to lack of accessible data. Nuclear fuel cycle scenarios varying spent fuel reprocessing, depleted uranium re-enrichment, enrichment assays, and use of fast neutron reactors, were established. They were then assessed according to environmental, economic and social criteria such as resource depletion, waste production, chemical and radiation emissions, costs, and proliferation risks. The most preferable scenario in the short term is a combination of reduced tails assay and enrichment grade, allowing a 17.9% reduction of uranium demand without significantly increasing environmental, economic, or social risks. In the long term, fast reactors could theoretically achieve a 99.4% decrease in uranium demand and nuclear waste production. However, this involves important costs and proliferation risks. Increasing material efficiency is not systematically correlated with the reduction of other risks. This suggests that an overall optimization of the nuclear fuel cycle is difficult to obtain. Therefore, criteria must be weighted according to stakeholder interests in order to determine the most sustainable solution. This paper models the flows of uranium and associated materials in Europe, and provides a decision support tool for identifying the trade-offs of the alternative nuclear fuel cycles considered.

(1-3)(1-6)-β-glucan-enriched materials from Lentinus edodes mushroom as a high-fibre and low-calorie flour substitute for baked foods.

PubMed

Kim, Juyoung; Lee, Seung Mi; Bae, In Young; Park, Hyuk-Gu; Gyu Lee, Hyeon; Lee, Suyong

2011-08-15

Extensive physiological and biological emphasis has been placed on pharmaceutical and medicinal uses of mushrooms containing β-glucans, but their incorporation into processed functional foods is quite limited. Thus, low-grade Lentinus edodes mushrooms were utilised to produce β-glucan-enriched materials (BGEMs), which were evaluated as a high-fibre and low-calorie substitute for wheat flour. The fractions obtained from Lentinus edodes mushrooms contained 514 g kg⁻¹ of (1-3)-β-glucans with (1-6)-β-linked side chains and the chemical structure was confirmed by ¹³C NMR and FTIR spectroscopy. Replacement of a portion of the wheat flour with BGEMs resulted in the solutions with lower values of pasting parameters and also caused significant changes in starch gelatinisation. When BGEMs were incorporated into cake formulations, batter viscosity increased with more shear-thinning behaviours and elastic properties improved. Overall, the cakes containing more BGEMs showed decreased volume and increased hardness while no significant differences were observed between the control and BGEM cakes containing 1 g of β-glucan per serving. As a wheat flour substitute, the BGEMs that were prepared from low-grade Lentinus edodes mushrooms, could be successfully used to produce cakes containing 1 g of β-glucan per serving with quality attributes similar to those of the control. Copyright © 2011 Society of Chemical Industry.

Summary of the Effort to Use Active-induced Time Correlation Techniques to Measure the Enrichment of HEU

DOE Office of Scientific and Technical Information (OSTI.GOV)

McConchie, Seth M.; Crye, Jason Michael; Pena, Kirsten

2015-09-30

This document summarizes the effort to use active-induced time correlation techniques to measure the enrichment of bulk quantities of enriched uranium. In summary, these techniques use an external source to initiate fission chains, and the time distribution of the detected fission chain neutrons is sensitive to the fissile material enrichment. The number of neutrons emitted from a chain is driven by the multiplication of the item, and the enrichment is closely coupled to the multiplication of the item. As the enrichment increases (decreases), the multiplication increases (decreases) if the geometry is held constant. The time distribution of fission chain neutronsmore » is a complex function of the enrichment and material configuration. The enrichment contributes to the probability of a subsequent fission in a chain via the likelihood of fissioning on an even-numbered isotope versus an odd-numbered isotope. The material configuration contributes to the same probability via solid angle effects for neutrons inducing subsequent fissions and the presence of any moderating material. To simplify the ability to accurately measure the enrichment, an associated particle imaging (API) D-T neutron generator and an array of plastic scintillators are used to simultaneously image the item and detect the fission chain neutrons. The image is used to significantly limit the space of enrichment and material configuration and enable the enrichment to be determined unambiguously.« less

Chemically anomalous, pre-accretionally irradiated grains in interplanetary dust -- interstellar grains?. [Abstract only

NASA Technical Reports Server (NTRS)

Bradley, J. P.

1994-01-01

Ultrafine-grained matrix is a unique and fundamental building block of chondritic porous (CP) interplanetary dust particles. Most IDPs so far determined to be of cometary origin belong to the CP class. The matrix in CP IDPs is not homogeneous but rather a loose mixture of discrete single crystals (e.g., olivine, pyroxene, Fe sulfides) and polyphase grains. The petrographic diversity observed among the polyphase grains suggest that they were formed under variable physiochemical conditions. One particular class of polyphase grains are a dominant component in cometary IDPs. Although their occurrence is well documented, the terminology used to describe them is confused. They have been called many names. Here they are simply called GEMS (Glass with Embedded Metal and Sulfides). The bulk compositions of GEMS are within a factor of 3 chondritic (solar) for all major elements except C. Quantitative thin-film X-ray (EDS) analyses have shown that GEMS are systematically depleted in Mg and Si, enriched in S, Fe, and Ni, and stoichiometrically enriched in O. Electron energy-loss spectroscopy (EELS) suggests that the excess O is present as hydroxyl (-OH) groups. These same chemical 'anomalies' were observed in solar-wind-irradiated amorphous rims on the surfaces of IDPs, suggesting that the compositions of GEMS reflect prior exposure to ionizing radiation. In order to test this hypothesis, a sample of Allende (CV3) matrix was exposed to proton flux. Radiation-damaged amorphous rims on olivine and pyroxene crystals in the Allende sample were found to be depleted in Mg and Ca, enriched in S, Fe, and Ni, and stoichiometrically enriched in O. Thus, the compositions of GEMS are indeed consistent with exposure to ionizing radiation. This study suggests that chemical as well as isotopic anomalies may be used to identify presolar interstellar grains in primitive meteoritic materials.

Development of flame resistant treatment for Nomex fibrous structures

NASA Technical Reports Server (NTRS)

Toy, M. S.

1977-01-01

Flame resistant fibrous materials for space shuttle application were developed through chemical modification of commercially available aromatic polyamide fibrous products. The new surface treatment was achieved in the laboratory by ultraviolet activation of the fabric in the presence of fluoroolefin monomers and a diluent gas. The monomers grafted under these conditions provide the improved properties of the fabric in flame resistance, chemical inertness, and nonwettability without the sacrifice of color or physical properties. The laboratory reaction vessel was scaled-up to a batch continuous process, which treats ten yards of the commercial width textiles. The treated commercial width Nomex (HT-10-41) from the scaled-up reactor is self-extinguishing in an oxygen-enriched environment, water-repellent, soft, silky, and improved in chemical resistance. Unlike most textile processes, the grafting unit operates under dry conditions and no chemical by-products have to be washed out of the finished product.

Numerical study of the origin and stability of chemically distinct reservoirs deep in Earth's mantle

NASA Astrophysics Data System (ADS)

van Thienen, P.; van Summeren, J.; van der Hilst, R. D.; van den Berg, A. P.; Vlaar, N. J.

Seismic tomography is providing mounting evidence for large scale compositional heterogeneity deep in Earth's mantle; also, the diverse geochemical and isotopic signatures observed in oceanic basalts suggest that the mantle is not chemically homogeneous. Isotopic studies on Archean rocks indicate that mantle inhomogeneity may have existed for most of the Earth's history. One important component may be recycled oceanic crust, residing at the base of the mantle. We investigate, by numerical modeling, if such reservoirs may have been formed in the early Earth, before plate tectonics (and subduction) were possible, and how they have survived—and evolved—since then. During Earth's early evolution, thick basaltic crust may have sunk episodically into the mantle in short but vigorous diapiric resurfacing events. These sections of crust may have resided at the base of the mantle for very long times. Entrainment of material from the enriched reservoirs thus produced may account for enriched mantle and high-μ signatures in oceanic basalts, whereas deep subduction events may have shaped and replenished deep mantle reservoirs. Our modeling shows that (1) convective instabilities and resurfacing may have produced deep enriched mantle reservoirs before the era of plate tectonics; (2) such formation is qualitatively consistent with the geochemical record, which shows multiple distinct ocean island basalt sources; and (3) reservoirs thus produced may be stable for billions of years.

A Geochemical View on the Interplay Between Earth's Mantle and Crust

NASA Astrophysics Data System (ADS)

Chauvel, C.

2017-12-01

Over most of Earth history, oceanic and continental crust was created and destroyed. The formation of both types of crust involves the crystallization and differentiation of magmas producing by mantle melting. Their destruction proceeds by mechanical erosion and weathering above sea level, chemical alteration on the seafloor, and bulk recycling in subduction zones. All these processes enrich of some chemical element and deplete others but each process has its own effect on chemical elements. While the flux of material from mantle to crust is well understood, the return flux is much more complex. In contrast to mantle processes, erosion, weathering, chemical alteration and sedimentary processes strongly decouple elements such as the rare earths and high-field strength elements due to their different solubilities in surface fluids and mineralogical sorting during transport. Soluble elements such as strontium or uranium are quantitatively transported to the ocean by rivers and decoupled from less soluble elements. Over geological time, such decoupling significantly influences the extent to which chemical elements remain at the Earth's surface or find their way back to the mantle through subduction zones. For example, elements like Hf or Nd are retained in heavy minerals on continents whereas U and Sr are transported to the oceans and then in subduction zones to the mantle. The consequence is that different radiogenic isotopic systems give disparate age estimates for the continental crust; e.g, Hf ages could be too old. In subduction zones, chemical elements are also decoupled, due to contrasting behavior during dehydration or melting in subducting slabs. The material sent back into the mantle is generally enriched in non-soluble elements while most fluid-mobile elements return to the crust. This, in turn, affects the relationship between the Rb-Sr, Sm-Nd, Lu-Hf and U-Th-Pb isotopic systems and creates correlations unlike those based on magmatic processes. By quantifying the difference between isotopic arrays created by magmatic processes vs. surface and subduction processes, we can determine how crust recycling creates isotopic heterogeneities in the mantle.

New developments in understanding the r-process from observations of metal-poor stars

NASA Astrophysics Data System (ADS)

Frebel, Anna

2015-04-01

In their atmospheres, old metal-poor Galactic stars retain detailed information about the chemical composition of the interstellar medium at the time of their birth. Extracting such stellar abundances enables us to reconstruct the beginning of the chemical evolution shortly after the Big Bang. About 5% of metal-poor stars with [Fe/H] < - 2 . 5 display in their spectrum a strong enhancement of neutron-capture elements associated with the rapid (r-) nucleosynthesis process that is responsible for the production of the heaviest elements in the Universe. This fortuity provides a unique opportunity of bringing together astrophysics and nuclear physics because these objects act as ``cosmic lab'' for both fields of study. The so-called r-process stars are thought to have formed from material enriched in heavy neutron-capture elements that were created during an r-process event in a previous generation supernova. It appears that the few stars known with this rare chemical signature all follow the scaled solar r-process pattern (for the heaviest elements with 56 <= Z <= 90 that is). This suggests that the r-process is universal - a surprising empirical finding and a solid result that can not be obtained from any laboratory on earth. While much research has been devoted to establishing this pattern, little attention has been given to the overall level of enhancement. New results will be presented on the full extent of r-process element enrichment as observed in metal-poor stars. The challenge lies in determining how the r-process material in the earliest gas clouds was mixed and diluted. Assuming individual r-process events to have contributed the observed r-process elements. We provide empirical estimates on the amount of r-process material produced. This should become a crucial constraint for theoretical nuclear physics models of heavy element nucleosynthesis.

Molybdenum isotope fractionation during acid leaching of a granitic uranium ore

NASA Astrophysics Data System (ADS)

Migeon, Valérie; Bourdon, Bernard; Pili, Eric; Fitoussi, Caroline

2018-06-01

As an attempt to prevent illicit trafficking of nuclear materials, it is critical to identify the origin and transformation of uranium materials from the nuclear fuel cycle based on chemical and isotope tracers. The potential of molybdenum (Mo) isotopes as tracers is considered in this study. We focused on leaching, the first industrial process used to release uranium from ores, which is also known to extract Mo depending on chemical conditions. Batch experiments were performed in the laboratory with pH ranging from 0.3 to 5.5 in sulfuric acid. In order to span a large range in uranium and molybdenum yields, oxidizers such as nitric acid, hydrogen peroxide and manganese dioxide were also added. An enrichment in heavy Mo isotopes is produced in the solution during leaching of a granitic uranium ore, when Mo recovery is not quantitative. At least two Mo reservoirs were identified in the ore: ∼40% as Mo oxides soluble in water or sulfuric acid, and ∼40% of Mo hosted in sulfides soluble in nitric acid or hydrogen peroxide. At pH > 1.8, adsorption and/or precipitation processes induce a decrease in Mo yields with time correlated with large Mo isotope fractionations. Quantitative models were used to evaluate the relative importance of the processes involved in Mo isotope fractionation: dissolution, adsorption, desorption, precipitation, polymerization and depolymerization. Model best fits are obtained when combining the effects of dissolution/precipitation, and adsorption/desorption onto secondary minerals. These processes are inferred to produce an equilibrium isotope fractionation, with an enrichment in heavy Mo isotopes in the liquid phase and in light isotopes in the solid phase. Quantification of Mo isotope fractionation resulting from uranium leaching is thus a promising tool to trace the origin and transformation of nuclear materials. Our observations of Mo leaching are also consistent with observations of natural Mo isotope fractionation taking place during chemical weathering in terrestrial environments where the role of secondary processes such as adsorption is significant.

Calcium and Titanium Isotope Fractionation in CAIS: Tracers of Condensation and Inheritance in the Early Solar Protoplanetary Disk

NASA Technical Reports Server (NTRS)

Simon, J. I.; Jordan, M. K.; Tappa, M. J.; Kohl, I. E.; Young, E. D.

2016-01-01

The chemical and isotopic compositions of calcium-aluminum-rich inclusions (CAIs) can be used to understand the conditions present in the protoplantary disk where they formed. The isotopic compositions of these early-formed nebular materials are largely controlled by chemical volatility. The isotopic effects of evaporation/sublimation, which are well explained by both theory and experimental work, lead to enrichments of the heavy isotopes that are often exhibited by the moderately refractory elements Mg and Si. Less well understood are the isotopic effects of condensation, which limits our ability to determine whether a CAI is a primary condensate and/or retains any evidence of its primordial formation history.

Silica Retention and Enrichment in Open-System Chemical Weathering on Mars

NASA Technical Reports Server (NTRS)

Yen, A. S.; Ming, D. W.; Gellert, R.; Clark, B. C.; Mittlefehldt, D. W.; Morris, R. V.; Thompson, L. M.; Berger, J.

2015-01-01

Chemical signatures of weathering are evident in the Alpha Particle X-ray Spectrometer (APXS) datasets from Gusev Crater, Meridiani Planum, and Gale Crater. Comparisons across the landing sites show consistent patterns indicating silica retention and/or enrichment in open-system aqueous alteration.

75 FR 44817 - Notice of Availability of Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-29

... Uranium Enrichment Fuel Cycle Facility Inspection Reports Regarding Louisiana Energy Services, National... Enrichment Branch, Division of Fuel Cycle Safety and Safeguards, Office of Nuclear Material Safety and... Enrichment Branch, Division of Fuel Cycle Safety and Safeguards, Office of Nuclear Material Safety and...

Cement and concrete

NASA Technical Reports Server (NTRS)

Corley, Gene; Haskin, Larry A.

1992-01-01

To produce lunar cement, high-temperature processing will be required. It may be possible to make calcium-rich silicate and aluminate for cement by solar heating of lunar pyroxene and feldspar, or chemical treatment may be required to enrich the calcium and aluminum in lunar soil. The effects of magnesium and ferrous iron present in the starting materials and products would need to be evaluated. So would the problems of grinding to produce cement, mixing, forming in vacuo and low gravity, and minimizing water loss.

Can Low Water/Rock Hydrothermal Alteration of Impact Materials Explain the Rock Component of the Martian Soil?

NASA Technical Reports Server (NTRS)

Nelson, M. J.; Newsom, H. E.

2003-01-01

The martian regolith is a globally homogenized product of chemical and aeolian weathering processes. The soil is thought to consist of a rock component, with lesser amounts of mobile elements (Ca, Na, and K) than a presumed protolith, and a salt or mobile element component enriched in sulfur and chlorine. In this study we consider the contributions of hydrothermal processes to the origin of the rock component of the martian soil.

187Os-186Os and He Isotope Systematics of Iceland Picrites

NASA Astrophysics Data System (ADS)

Brandon, A. D.; Brandon, A. D.; Graham, D.; Gautason, B.

2001-12-01

Iceland is one of the longest-lived modern plumes, and seismic imaging supports a model where the roots of this plume are at the base of the lower mantle. Hence, Os isotopic data for lavas from this plume are ideal for further testing the role of core-mantle chemical exchange at the site of plume generation in the lower mantle, and for addressing the origin of Os-He isotopic variation in plumes. Recent work has shown that lavas from some plume systems (Hawaii, Noril'sk-Siberia, Gorgona) show coupled enrichments in 186Os/188Os and 187Os/188Os, not observed in upper mantle materials including abyssal peridotites. Picrites from Hawaii display a positive correlation between 186Os/188Os and He isotopes (R/Ra), where range in 186Os/188Os of 0.119834+/-28 to 0.1198475+/-29 and corresponding R/Ra from +7 to +25. These systematics are consistent with a lower mantle source for the radiogenic 186Os signal in the Hawaiian plume. The coupled Os enrichments in these plumes has been attributed to core-mantle chemical exchange, consistent with generation of the Hawaiian plume at the base of the lower mantle in D". Other potentially viable models await additional scrutiny. New He isotope and high precision 186Os/188Os and 187Os/188Os measurements for Iceland picrites show unique systematics compared to Hawaii. These picrites have 187Os/188Os ranging from 0.1297 to 0.1381 and R/Ra of +9 to +18, with generally higher R/Ra correlating with higher 187Os/188Os. Unlike the Hawaiian picrites from Hualalai and Loihi, which have coupled enrichments in 186Os/188Os and 187Os/188Os, the Iceland picrites show no enrichment 186Os/188Os - 0.1198363+/-28 (2s, n=14). Such Os-He isotopic variations require one end-member source that has high R/Ra, coupled with a long term elevated Re/Os and Pt/Os similar to that of the upper mantle. These systematics are inconsistent with either known upper mantle materials or those purported for ancient recycled slabs and may be a previously unidentified component in the lower mantle.

Melting and Its Influence on the Long-term Evolution of the Lower Mantle Heterogeneities (LLSVP and ULVZ)

NASA Astrophysics Data System (ADS)

Fomin, I.; Tackley, P. J.

2017-12-01

Recent investigations have shown mantle solidus close to the range of proposed core-mantle boundary (CMB) temperatures (e.g. [Andrault et al., 2011, 2014], [de Koker et al., 2013]). Certain fraction of distinct rocks may reduce the effective melting temperature to values below the CMB temperature. It is especially true for iron enriched materials such as MORB [Nomura et al., 2011], BIF [Kato et al., 2016], iron-rich periclase [Boukare et al., 2015] and other rock species used to explain observed seismic anomalies. Computer simulations allow to study evolution and stability for chemically distinct piles proposed from geophysical data. Previous researches (e.g. [Mulyukova et al., 2015]) found those piles stirring in several hundreds of Ma. Our investigation adds influence of melting and following chemical differentiation on preservation of such structures.We present StagYY code [Tackley et al., 2008] with extended set of routines to model melting, melt redistribution and melt-dependent rheology in addition to solid-state mantle convection to reveal fate of chemically distinct piles in long-term (millions of years) perspective. A new point of our approach is usage of chemically independent oxides to describe rock composition and physical properties. Thin layers homogenize in few tens of millions of years despite whether melting happens or not. Thick structures (like periclase piles proposed for ULVZ [Wicks et al., 2010] or MORB-bearing domes for LLSVP [Ohta et al., 2008]) undergo partial melting if CMB temperature is above 3700K. Melt migration results in extraction of fusible components and therefore segregation of iron-enriched material. However, we weren't able to obtain any stabilized layer of iron-rich partially molten material at the CMB, because ongoing interaction and reequilibration of melt and solid results in buoyant liquids spreading to the adjacent mantle. Rheological influence of melt on bulk rock properties reduces time pile can exist.Our modeling puts severe constraints on the presence and fate of chemical heterogeneities in the lowermost mantle. Melting enhances stirring of such heterogeneities and generally no silicate melt can be stabilized at CMB for long time. Only low CMB temperatures (generally lower than 3700 K) allow anomalies to exist for geological periods of time (hundreds of Ma).

Chemical synthesis of biologically active tat trans-activating protein of human immunodeficiency virus type 1.

PubMed Central

Chun, R; Glabe, C G; Fan, H

1990-01-01

Full-length (86-residue) polypeptide corresponding to the human immunodeficiency virus type 1 tat trans-activating protein was chemically synthesized on a semiautomated apparatus, using an Fmoc amino acid continuous-flow strategy. The bulk material was relatively homogeneous, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing, and it showed trans-activating activity when scrape loaded into cells containing a human immunodeficiency virus long terminal repeat-chloramphenicol acetyl-transferase reporter plasmid. Reverse-phase high-pressure liquid chromatography yielded a rather broad elution profile, and assays across the column for biological activity indicated a sharper peak. Thus, high-pressure liquid chromatography provided for enrichment of biological activity. Fast atom bombardment-mass spectrometry of tryptic digests of synthetic tat identified several of the predicted tryptic peptides, consistent with accurate chemical synthesis. Images PMID:2186178

Organic Matter in Cosmic Dust

PubMed Central

Sandford, Scott A.; Engrand, Cecile; Rotundi, Alessandra

2018-01-01

Organics are observed to be a significant component of cosmic dust in nearly all environments were dust is observed. In many cases only remote telescope observations of these materials are obtainable and our knowledge of the nature of these materials is very basic. However, it is possible to obtain actual samples of extraterrestrial dust in the Earth’s stratosphere, in Antarctic ice and snow, in near-Earth orbit, and via spacecraft missions to asteroids and comets. It is clear that cosmic dust contains a diverse population of organic materials that owe their origins to a variety of chemical processes occurring in many different environments. The presence of isotopic enrichments of D and 15N suggests that many of these organic materials have an interstellar/protosolar heritage. The study of these samples is of considerable importance since they are the best preserved materials of the early Solar System available. PMID:29422977

Detailed Abundances in a Metal-Poor Stellar Stream

NASA Astrophysics Data System (ADS)

Roederer, I. U.; Sneden, C.; Thompson, I. B.; Preston, G. W.; Shectman, S. A.

2010-10-01

We present the results of a detailed abundance analysis of one of the confirmed building blocks of the Milky Way stellar halo, a kinematically-coherent metal-poor stellar stream. We have obtained high resolution and high S/N spectra of 8 confirmed and 4 rejected stream members using the MIKE spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory and the 2dCoude spectrograph on the Smith Telescope at McDonald Observatory. We have derived abundances or upper limits for nearly 50 species of more than 40 elements in each of these stars. The stream members show a range of metallicity (-2.5 < [Fe/H] < -1.5) but are otherwise chemically homogeneous, with the same star-to-star chemical dispersion in [X/Fe] as halo stars. They show no evolution in the α or Fe-group elements over the range of metallicity. The stream does not resemble a globular cluster in that its members show a range of metallicities, and the small chemical dispersion and lack of chemical evolution demonstrate that it is also unlike the classical Milky Way dwarf spheroidal galaxies. Our results support the notion that a significant fraction of the Milky Way stellar halo was formed from accreted systems, and these systems likely did not resemble the present-day globular clusters or luminous dwarf galaxies. This stream is mildly enriched (in, e.g., [Eu/Fe]) by material produced by the main and weak components of the rapid neutron-capture process and shows no evidence for enrichment by the slow neutron-capture process. Except for the observed metallicity range of the stream stars, the enrichment pattern of the stream is nearly identical to that of the massive metal-poor globular cluster M15. The kinematics of M15 and the stream are also similar. It is possible that both systems may have originated from a common progenitor but not likely that the stream originated from M15.

Assessment of chemically separated carbon nanotubes for nanoelectronics.

PubMed

Zhang, Li; Zaric, Sasa; Tu, Xiaomin; Wang, Xinran; Zhao, Wei; Dai, Hongjie

2008-02-27

It remains an elusive goal to obtain high performance single-walled carbon-nanotube (SWNT) electronics such as field effect transistors (FETs) composed of single- or few-chirality SWNTs, due to broad distributions in as-grown materials. Much progress has been made by various separation approaches to obtain materials enriched in metal or semiconducting nanotubes or even in single chiralties. However, research in validating SWNT separations by electrical transport measurements and building functional electronic devices has been scarce. Here, we performed length, diameter, and chirality separation of DNA functionalized HiPco SWNTs by chromatography methods, and we characterized the chiralities by photoluminescence excitation spectroscopy, optical absorption spectroscopy, and electrical transport measurements. The use of these combined methods provided deeper insight to the degree of separation than either technique alone. Separation of SWNTs by chirality and diameter occurred at varying degrees that decreased with increasing tube diameter. This calls for new separation methods capable of metallicity or chirality separation of large diameter SWNTs (in the approximately 1.5 nm range) needed for high performance nanoelectronics. With most of the separated fractions enriched in semiconducting SWNTs, nanotubes placed in parallel in short-channel (approximately 200 nm) electrical devices fail to produce FETs with high on/off switching, indicating incomplete elimination of metallic species. In rare cases with a certain separated SWNT fraction, we were able to fabricate FET devices composed of small-diameter, chemically separated SWNTs in parallel, with high on-/off-current (I(on)/I(off)) ratios up to 105 owing to semiconducting SWNTs with only a few (n,m) chiralities in the fraction. This was the first time that chemically separated SWNTs were used for short channel, all-semiconducting SWNT electronics dominant by just a few (n,m)'s. Nevertheless, the results suggest that much improved chemical separation methods are needed to produce nanotube electronics at a large scale.

Phosphorus transformations in plant-based and bio-waste materials induced by pyrolysis.

PubMed

Robinson, James Stephen; Baumann, Karen; Hu, Yongfeng; Hagemann, Philipp; Kebelmann, Lutz; Leinweber, Peter

2018-01-01

Strategies are needed to increase the sustainability of phosphorus (P) fertiliser management in agriculture. This paper reports on the potential of pyrolysis treatment to recycle P from renewable materials previously regarded as wastes. The study used K-edge X-ray absorption near-edge structure (XANES) spectroscopy to examine chemical forms of P in the waste feedstock materials and corresponding biochars (pyrolysis at 480-500 °C) of four ligno-cellulosic, plant-based residues and five relatively P-rich livestock and water-treatment by-products, to acquire information on changes in potential P fertiliser value. Pyrolysis enriched P in the biochars by factors of 1.3-4.3, thus offering wide-ranging P fertiliser potential. XANES spectroscopy revealed hydroxyapatite (HAP) as one of the dominant chemical P compounds in the feedstocks, ranging from 14% (rice husks) to 98% (animal bone) of total P. For most materials, pyrolysis increased the proportion of HAP, and pyrophosphates were generated in several cases. These alterations possibly lead to diversity in the P solubility characteristics of the biochars if used as soil amendments; this is an important property of environmentally sound P fertilisers.

A new generation of 99.999% enriched 28Si single crystals for the determination of Avogadro’s constant

NASA Astrophysics Data System (ADS)

Abrosimov, N. V.; Aref'ev, D. G.; Becker, P.; Bettin, H.; Bulanov, A. D.; Churbanov, M. F.; Filimonov, S. V.; Gavva, V. A.; Godisov, O. N.; Gusev, A. V.; Kotereva, T. V.; Nietzold, D.; Peters, M.; Potapov, A. M.; Pohl, H.-J.; Pramann, A.; Riemann, H.; Scheel, P.-T.; Stosch, R.; Wundrack, S.; Zakel, S.

2017-08-01

A metrological challenge is currently underway to replace the present definition of the kilogram. One prerequisite for this is that the Avogadro constant, N A, which defines the number of atoms in a mole, needs to be determined with a relative uncertainty of better than 2  ×  10-8. The method applied in this case is based on the x-ray crystal density experiment using silicon crystals. The first attempt, in which silicon of natural isotopic composition was used, failed. The solution chosen subsequently was the usage of silicon highly enriched in 28Si from Russia. First, this paper reviews previous efforts from the very first beginnings to an international collaboration with the goal of producing a 28Si single crystal with a mass of 5 kg, an enrichment greater than 0.9999 and of sufficient chemical purity. Then the paper describes the activities of a follow-up project, conducted by PTB, to produce a new generation of highly enriched silicon in order to demonstrate the quasi-industrial and reliable production of more than 12 kg of the 28Si material with enrichments of five nines. The intention of this project is also to show the availability of 28Si single crystals as a guarantee for the future realisation of the redefined kilogram.

Electrostatic Separator for Beneficiation of Lunar Soil

NASA Technical Reports Server (NTRS)

Quinn, Jacqueline; Arens, Ellen; Trigwell, Steve; Captain, James

2010-01-01

A charge separator has been constructed for use in a lunar environment that will allow for separation of minerals from lunar soil. In the present experiments, whole lunar dust as received was used. The approach taken here was that beneficiation of ores into an industrial feedstock grade may be more efficient. Refinement or enrichment of specific minerals in the soil before it is chemically processed may be more desirable as it would reduce the size and energy requirements necessary to produce the virgin material, and it may significantly reduce the process complexity. The principle is that minerals of different composition and work function will charge differently when tribocharged against different materials, and hence be separated in an electric field.

Rye flour enriched with arabinoxylans in rye bread making.

PubMed

Buksa, Krzysztof; Nowotna, Anna; Ziobro, Rafał; Gambuś, Halina

2015-01-01

The aim of the study was to investigate physical and chemical properties of preparations of water soluble arabinoxylans (arabinoxylan-enriched flour) obtained by industrial method and their derivatives (obtained by hydrolysis and cross-linking of aranbinoxylans), as well as their impact on baking properties of rye flours. Additionally, these results were compared with highly purified arabinoxylans prepared by laboratory method and well characterized in the literature. Flour enriched with arabinoxylans was obtained by industrial method involving air separation of flour particles. It was characterized by 8.6% arabinoxylan content, lack of insoluble material and substantial residue (67%) of starch and dextrins. The addition of all industrial method preparations in amount of 10% (i.e. approx. 1% water soluble arabinoxylans), to rye flours resulted in an increase in water absorption, bread volume and decrease in hardness of the bread crumb and the effect was especially strong in the case of flour type 720. Due to the easiness of isolation procedure, industrial method preparation could be advised as an improver for rye bread making. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Effect of cranberry (Vaccinium macrocarpon) oligosaccharides on the formation of advanced glycation end-products.

PubMed

Sun, Jiadong; Liu, Weixi; Ma, Hang; Marais, Jannie P J; Khoo, Christina; Dain, Joel A; Rowley, David C; Seeram, Navindra P

2016-06-16

BACKGROUND: The formation and accumulation of advanced glycation end-products (AGEs) are implicated in several chronic human illnesses including type-2 diabetes, renal failure, and neurodegenerative diseases. The cranberry ( Vaccinium macrocarpon ) fruit has been previously reported to show anti-AGEs effects, attributed primarily to its phenolic constituents. However, there is lack of similar data on the non-phenolic constituents found in the cranberry fruit, in particular, its carbohydrate constituents. Herein, a chemically characterized oligosaccharide-enriched fraction purified from the cranberry fruit was evaluated for its potential anti-AGEs and free radical scavenging effects. OBJECTIVE: The aim of this study was to evaluate the in vitro anti-AGEs and free radical scavenging effects of a chemically characterized oligosaccharide-enriched fraction purified from the North American cranberry ( Vaccinium macrocarpon ) fruit. METHOD: The cranberry oligosaccharide-enriched fraction was purified from cranberry hull powder and characterized based on spectroscopic and spectrometric (NMR, MALDI-TOF-MS, and HPAEC-PAD) data. The oligosaccharide-enriched fraction was evaluated for its anti-AGEs and free radical scavenging effects by the bovine serum albumin-fructose, and DPPH assays, respectively. RESULTS: Fractionation of cranberry hull material yielded an oligosaccharide-enriched fraction named Cranf1b-CL. The 1 H NMR and MALDI-TOF-MS revealed that Cranf1b-CL consists of oligosaccharides ranging primarily from 6-mers to 9-mers. The monosaccharide composition of Cranf1b-CL was arabinose (25%), galactose (5%), glucose (47%) and xylose (23%). In the bovine serum albumin-fructose assay, Cranf1b-CL inhibited AGEs formation in a concentration-dependent manner with comparable activity to the synthetic antiglycating agent, aminoguanidine, used as the positive control (57 vs. 75%; both at 500μg/mL). In the DPPH free radical scavenging assay, Cranf1b-CL showed superior activity to the synthetic commercial antioxidant, butylated hydroxytoluene, used as the positive control (IC 50  = 680 vs. 2200μg/mL, respectively). CONCLUSION: The in vitro anti-AGEs and free radical scavenging effects of cranberry oligosaccharides support previous data suggesting that these constituents may also contribute to biological effects of the whole fruit beyond its phenolic constituents alone. Also, this is the first study to evaluate a chemically characterized oligosaccharide fraction purified from the North American cranberry fruit for anti-AGEs and free radical scavenging properties.

Effect of cranberry (Vaccinium macrocarpon) oligosaccharides on the formation of advanced glycation end-products

PubMed Central

Sun, Jiadong; Liu, Weixi; Ma, Hang; Marais, Jannie P. J.; Khoo, Christina; Dain, Joel A.; Rowley, David C.; Seeram, Navindra P.

2016-01-01

BACKGROUND: The formation and accumulation of advanced glycation end-products (AGEs) are implicated in several chronic human illnesses including type-2 diabetes, renal failure, and neurodegenerative diseases. The cranberry (Vaccinium macrocarpon) fruit has been previously reported to show anti-AGEs effects, attributed primarily to its phenolic constituents. However, there is lack of similar data on the non-phenolic constituents found in the cranberry fruit, in particular, its carbohydrate constituents. Herein, a chemically characterized oligosaccharide-enriched fraction purified from the cranberry fruit was evaluated for its potential anti-AGEs and free radical scavenging effects. OBJECTIVE: The aim of this study was to evaluate the in vitro anti-AGEs and free radical scavenging effects of a chemically characterized oligosaccharide-enriched fraction purified from the North American cranberry (Vaccinium macrocarpon) fruit. METHOD: The cranberry oligosaccharide-enriched fraction was purified from cranberry hull powder and characterized based on spectroscopic and spectrometric (NMR, MALDI-TOF-MS, and HPAEC-PAD) data. The oligosaccharide-enriched fraction was evaluated for its anti-AGEs and free radical scavenging effects by the bovine serum albumin-fructose, and DPPH assays, respectively. RESULTS: Fractionation of cranberry hull material yielded an oligosaccharide-enriched fraction named Cranf1b-CL. The 1H NMR and MALDI-TOF-MS revealed that Cranf1b-CL consists of oligosaccharides ranging primarily from 6-mers to 9-mers. The monosaccharide composition of Cranf1b-CL was arabinose (25%), galactose (5%), glucose (47%) and xylose (23%). In the bovine serum albumin-fructose assay, Cranf1b-CL inhibited AGEs formation in a concentration-dependent manner with comparable activity to the synthetic antiglycating agent, aminoguanidine, used as the positive control (57 vs. 75%; both at 500μg/mL). In the DPPH free radical scavenging assay, Cranf1b-CL showed superior activity to the synthetic commercial antioxidant, butylated hydroxytoluene, used as the positive control (IC50 = 680 vs. 2200μg/mL, respectively). CONCLUSION: The in vitro anti-AGEs and free radical scavenging effects of cranberry oligosaccharides support previous data suggesting that these constituents may also contribute to biological effects of the whole fruit beyond its phenolic constituents alone. Also, this is the first study to evaluate a chemically characterized oligosaccharide fraction purified from the North American cranberry fruit for anti-AGEs and free radical scavenging properties. PMID:28649289

Fine-Grained Rims in the Allan Hills 81002 and Lewis Cliff 90500 CM2 Meteorites: Their Origin and Modification

NASA Technical Reports Server (NTRS)

Hua, X.; Wang, J.; Buseck, P. R.

2002-01-01

Antarctic CM meteorites Allan Hills (ALH) 8 1002 and Lewis Cliff (LEW) 90500 contain abundant fine-grained rims (FGRs) that surround a variety of coarse-grained objects. FGRs from both meteorites have similar compositions and petrographic features, independent of their enclosed objects. The FGRs are chemically homogeneous at the 10 m scale for major and minor elements and at the 25 m scale for trace elements. They display accretionary features and contain large amounts of volatiles, presumably water. They are depleted in Ca, Mn, and S but enriched in P. All FGRs show a slightly fractionated rare earth element (REE) pattern, with enrichments of Gd and Yb and depletion of Er. Gd is twice as abundant as Er. Our results indicate that those FGRs are not genetically related to their enclosed cores. They were sampled from a reservoir of homogeneously mixed dust, prior to accretion to their parent body. The rim materials subsequently experienced aqueous alteration under identical conditions. Based on their mineral, textural, and especially chemical similarities, we conclude that ALH 8 1002 and LEW 90500 likely have a similar or identical source.

Detection of interstellar DNC - Difficulties of chemical equilibrium hypothesis for enrichment

NASA Technical Reports Server (NTRS)

Godfrey, P. D.; Brown, R. D.; Gunn, H. I.; Blackman, G. L.; Storey, J. W. V.

1977-01-01

The J = 1-0 transition of DNC at 76.3058 GHz has been observed in emission in NGC 2264. Comparison with previous observations of HN(C-13) indicates that deuterium is enriched in DNC similarly to the enrichment reported for DCO(+) in this source. The DNC/HNC ratio is estimated to be about 1/24. The results cannot readily be interpreted in terms of chemical equilibria relating to the formation of DNC. It is suggested that the explanation must be sought in isotope effects on rates of formation of interstellar molecules.

The mini-CIDEX GC/IMS: Analysis of cometary ice and dust

NASA Technical Reports Server (NTRS)

Kojiro, Daniel R.; Carle, Glenn C.; Humphry, Donald E.; Shao, Maxine; Takeuchi, Nori

1995-01-01

Comets are recognized as among the most scientifically important objects in the solar system. They are presumed relics of the early primitive material in the solar nebula and are believed to have provided a general enrichment of volatiles to the inner solar system. The Cometary Coma Chemical Composition (C4) Mission, a proposed Discovery-Class Mission, will analyze materials released into the coma, providing information leading to the understanding of the chemical composition and make-up of the cometary nucleus. As one of two scientific instruments in the C4 spacecraft, an advanced and streamlined version of the Cometary Ice and Dust Experiment (CIDEX), a mini-CIDEX, will employ an X-Ray Fluorescence (XRF) spectrometer to determine bulk elemental composition of cometary dust grains and a Gas Chromatograph/Ion Mobility Spectrometer (GC/IMS) for determination of the molecular composition of dust and ices following stepwise pyrolysis and combustion. A description of the mini-CIDEX IMS will be provided as well as data from analyses conducted using the mini-CIDEX breadboard instrument.

Determination of chemical purity and isotopic composition of natural and carbon-13-labeled arsenobetaine bromide standards by quantitative(1)H-NMR.

PubMed

Le, Phuong-Mai; Ding, Jianfu; Leek, Donald M; Mester, Zoltan; Robertson, Gilles; Windust, Anthony; Meija, Juris

2016-10-01

In this study, we report the characterization of three arsenobetaine-certified reference materials by quantitative NMR. We have synthesized an arsenobetaine bromide high-purity standard of natural isotopic composition (ABET-1) and two carbon-13-labeled isotopic standards (BBET-1 and CBET-1). Assignments of the chemical purity and isotopic composition are not trivial in the case of arsenobetaine, and in this study we utilized quantitative(1)H-NMR techniques for the determination of the mass fractions (chemical purity). The isotopic purity of all three standards was also assessed by NMR from the carbon-13 satellite signals. The standards are non-hygroscopic, high-purity (ca. 0.99 g/g), and the carbon-13 enrichment for both isotopic standards is x((13)C)≈0.99. These standards are designed for use as primary calibrators for mass spectrometric determination of arsenobetaine in environmental samples.

Results and Implications of Mineralogical Models for Chemical Sediments at Meridiani Planum

NASA Technical Reports Server (NTRS)

Clark, B. C.; McLennan, S. M.; Morris, R. V.; Gellert, R.; Jolliff, B.; Knoll, A.; Lowenstein, T. K.; Ming, D. W.; Tosca, N. J.; Christensen, P. R.

2005-01-01

The Mars Exploration Rover (MER) "Opportunity" has explored chemically-enriched sedimentary outcrops at Meridiani Planum, Mars. In its first year, three different crater sites - Eagle, Fram and Endurance - have been explored. Nineteen high-interest outcrop rocks were investigated by first grinding a hole to reach the interior (using the Rock Abrasion Tool, RAT), and then conducting APXS (alpha particle x-ray spectrometry) analysis, MB (M ssbauer) analysis, and close up imaging (MI, microscopic imager). Sixteen elements and four Fe-bearing minerals were assayed to good accuracy in each sample, producing 380 compositional data points. The Miniature Thermal Emission Spectrometer (Mini- TES) obtained spectra on outcrop materials which provide direct indication of several mineral classes. Preliminary reports on Eagle crater and three RAT samples have been published. Chemical trends and a derived mineralogical model for all RAT d outcrop samples to date has been developed.

Segregation and Alteration of Phenolic and Aliphatic Components of Root and Leaf Litter by Detritivores and Microbes

NASA Astrophysics Data System (ADS)

Filley, T. R.; Altmann, J.; Szlavecz, K. A.; Kalbitz, K.; Gamblin, D.; Nierop, K.

2012-12-01

The physical and microbial transformation of plant detritus in the litter layer and soil is accompanied by chemical separation of progressively soluble fractions and their movement into the rhizosphere driving subsequent soil processes. We investigated the combined action of specific detritivores, microbial decay, and leaching on the chemical separation of plant aromatic and aliphatic components from root, wood, and leaf tissue using 13C-TMAH thermochemolysis. This method enabled the simultaneous analysis of hydrolyzable tannin and lignin fragments, substituted fatty acids, and condensed tannin composition and revealed process-specific chemical transformations to plant secondary compounds. Long-term incubation and field sampling demonstrated how plant residues are progressively leached of the water soluble, oxidized fragments generated through decay. The residues appeared only slightly altered, in the case of brown rot wood, or enriched in aliphatic fragments, in the case of leaf and root tissue. Water extractable fractions were always selectively dominated by polyphenolics, either as demethylated lignin or tannins, and nearly devoid of aliphatic materials, despite high concentrations in the starting materials. Additionally, for plant materials with high tannin contents, such as pine needles, consumption and passage through some arthropod guts revealed what appeared to be microbially-mediated methylation of phenols, and a loss of tannins in leachates. These findings are indications for an in-situ phenol detoxification mechanism. This research provides important information regarding the links between biochemical decay and the chemical nature of organic matter removed and remaining in the soil profile.

10 CFR 74.33 - Nuclear material control and accounting for uranium enrichment facilities authorized to produce...

Code of Federal Regulations, 2011 CFR

2011-01-01

... enrichment facilities authorized to produce special nuclear material of low strategic significance. 74.33... NUCLEAR MATERIAL Special Nuclear Material of Low Strategic Significance § 74.33 Nuclear material control... strategic significance. (a) General performance objectives. Each licensee who is authorized by this chapter...

Chemical enrichment in Ultra-Faint Dwarf galaxies

NASA Astrophysics Data System (ADS)

Romano, Donatella

2016-08-01

Our view of the Milky Way's satellite population has radically changed after the discovery, ten years ago, of the first Ultra-Faint Dwarf galaxies (UFDs). These extremely faint, dark-matter dominated, scarcely evolved stellar systems are found in ever-increasing number in our cosmic neighbourhood and constitute a gold-mine for studies of early star formation conditions and early chemical enrichment pathways. Here we show what can be learned from the measurements of chemical abundances in UFD stars read through the lens of chemical evolution studies, point out the limitations of the classic approach, and discuss the way to go to improve the models.

Stacking Fault Enriching the Electronic and Transport Properties of Few-Layer Phosphorenes and Black Phosphorus.

PubMed

Lei, Shuangying; Wang, Han; Huang, Lan; Sun, Yi-Yang; Zhang, Shengbai

2016-02-10

Interface engineering is critical for enriching the electronic and transport properties of two-dimensional materials. Here, we identify a new stacking, named Aδ, in few-layer phosphorenes (FLPs) and black phosphorus (BP) based on first-principles calculation. With its low formation energy, the Aδ stacking could exist in FLPs and BP as a stacking fault. The presence of the Aδ stacking fault induces a direct to indirect transition of the band gap in FLPs. It also affects the carrier mobilities by significantly increasing the carrier effective masses. More importantly, the Aδ stacking enables the fabrication of a whole spectrum of lateral junctions with all the type-I, II, and III alignments simply through the manipulation of the van der Waals stacking without resorting to any chemical modification. This is achieved by the widely tunable electron affinity and ionization potential of FLPs and BP with the Aδ stacking.

Controlling Reaction Selectivity through the Surface Termination of Perovskite Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polo-Garzon, Felipe; Yang, Shi-Ze; Fung, Victor

2017-07-19

Although well known in the material science field, surface reconstruction of perovskites has not been implemented in heterogeneous catalysis. In this work, we employ multiple surface sensitive techniques to characterize the surface reconstruction of SrTiO3 (STO) after thermal pretreatment (Sr-enrichment) and chemical etching (Ti-enrichment). We show, using the conversion of 2-propanol as a probe reaction, that the surface reconstruction of STO can be controlled to greatly tune catalytic acid/base properties and consequently the reaction selectivities in a wide range, which are inaccessible using single metal oxides, either SrO or TiO2. Density functional theory (DFT) calculations well explain the selectivity tuningmore » and reaction mechanism on differently reconstructed surfaces of STO. Similar catalytic tunability is also observed on BaZrO3, highlighting the generality of the finding from this work.« less

Leaching behaviour of bottom ash from RDF high-temperature gasification plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gori, M., E-mail: manuela.gori@dicea.unifi.it; Pifferi, L.; Sirini, P.

2011-07-15

This study investigated the physical properties, the chemical composition and the leaching behaviour of two bottom ash (BA) samples from two different refuse derived fuel high-temperature gasification plants, as a function of particle size. The X-ray diffraction patterns showed that the materials contained large amounts of glass. This aspect was also confirmed by the results of availability and ANC leaching tests. Chemical composition indicated that Fe, Mn, Cu and Cr were the most abundant metals, with a slight enrichment in the finest fractions. Suitability of samples for inert waste landfilling and reuse was evaluated through the leaching test EN 12457-2.more » In one sample the concentration of all metals was below the limit set by law, while limits were exceeded for Cu, Cr and Ni in the other sample, where the finest fraction showed to give the main contribution to leaching of Cu and Ni. Preliminary results of physical and geotechnical characterisation indicated the suitability of vitrified BA for reuse in the field of civil engineering. The possible application of a size separation pre-treatment in order to improve the chemical characteristics of the materials was also discussed.« less

HExpoChem: a systems biology resource to explore human exposure to chemicals.

PubMed

Taboureau, Olivier; Jacobsen, Ulrik Plesner; Kalhauge, Christian; Edsgärd, Daniel; Rigina, Olga; Gupta, Ramneek; Audouze, Karine

2013-05-01

Humans are exposed to diverse hazardous chemicals daily. Although an exposure to these chemicals is suspected to have adverse effects on human health, mechanistic insights into how they interact with the human body are still limited. Therefore, acquisition of curated data and development of computational biology approaches are needed to assess the health risks of chemical exposure. Here we present HExpoChem, a tool based on environmental chemicals and their bioactivities on human proteins with the objective of aiding the qualitative exploration of human exposure to chemicals. The chemical-protein interactions have been enriched with a quality-scored human protein-protein interaction network, a protein-protein association network and a chemical-chemical interaction network, thus allowing the study of environmental chemicals through formation of protein complexes and phenotypic outcomes enrichment. HExpoChem is available at http://www.cbs.dtu.dk/services/HExpoChem-1.0/.

10 CFR Appendix E to Part 110 - Illustrative List of Chemical Exchange or Ion Exchange Enrichment Plant Equipment and Components...

Code of Federal Regulations, 2012 CFR

2012-01-01

.... A major design concern is to avoid contamination of the process streams with certain metal ions... internal turbine mixers), especially designed or prepared for uranium enrichment using the chemical...) or glass. The stage residence time of the columns is designed to be short (30 seconds or less). (2...

Microchip method for the enrichment of specific DNA sequences

DOEpatents

Mirzabekov, A.D.; Lysov, Y.P.; Shick, V.V.; Dubiley, S.A.

1998-12-22

A method for enriching specific genetic material sequences is provided, whereby oligonucleotide molecules complementary to the desired genetic material is first used to isolate the genetic material from a first source of genomic material. Then the genetic material is used as a label to isolate similar genetic sequences from other sources. 4 figs.

Microchip method for the enrichment of specific DNA sequences

DOEpatents

Mirzabekov, Andrei Darievich; Lysov, Yuri Petrovich; Shick, Valentine Vladimirovich; Dubiley, Svetlana Alekseevna

1998-01-01

A method for enriching specific genetic material sequences is provided, whereby oligonucleotide molecules complementary to the desired genetic material is first used to isolate the genetic material from a first source of genomic material. Then the genetic material is used as a label to isolate similar genetic sequences from other sources.

Lunar cement and lunar concrete

NASA Technical Reports Server (NTRS)

Lin, T. D.

1991-01-01

Results of a study to investigate methods of producing cements from lunar materials are presented. A chemical process and a differential volatilization process to enrich lime content in selected lunar materials were identified. One new cement made from lime and anorthite developed compressive strengths of 39 Mpa (5500 psi) for 1 inch paste cubes. The second, a hypothetical composition based on differential volatilization of basalt, formed a mineral glass which was activated with an alkaline additive. The 1 inch paste cubes, cured at 100C and 100 percent humidity, developed compressive strengths in excess of 49 Mpa (7100 psi). Also discussed are tests made with Apollo 16 lunar soil and an ongoing investigation of a proposed dry mix/steam injection procedure for casting concrete on the Moon.

Small-scale hero: Massive-star enrichment in the Hercules dwarf spheroidal

NASA Astrophysics Data System (ADS)

Koch, Andreas; Matteucci, Francesca; Feltzing, Sofia

2012-09-01

Dwarf spheroidal galaxies are often conjectured to be the sites of the first stars. The best current contenders for finding the chemical imprints from the enrichment by those massive objects are the ``ultrafaint dwarfs'' (UFDs). Here we present evidence for remarkably low heavy element abundances in the metal poor Hercules UFD. Combined with other peculiar abundance patterns this indicates that Hercules was likely only influenced by very few, massive explosive events - thus bearing the traces of an early, localized chemical enrichment with only very little other contributions from other sources at later times.

Carbon Characteristics and Biogeochemical Processes of Uranium Accumulating Organic Matter Rich Sediments in the Upper Colorado River Basin

NASA Astrophysics Data System (ADS)

Boye, K.; Noel, V.; Tfaily, M. M.; Dam, W. L.; Bargar, J.; Fendorf, S. E.

2015-12-01

Uranium plume persistence in groundwater aquifers is a problem on several former ore processing sites on floodplains in the upper Colorado River Basin. Earlier observations by our group and others at the Old Rifle Site, CO, have noted that U concentrations are highest in organic rich, fine-grained, and, therefore, diffusion limited sediment material. Due to the constantly evolving depositional environments of floodplains, surficial organic matter may become buried at various stages of decomposition, through sudden events such as overbank flooding and through the slower progression of river meandering. This creates a discontinuous subsurface distribution of organic-rich sediments, which are hotspots for microbial activity and thereby central to the subsurface cycling of contaminants (e.g. U) and biologically relevant elements (e.g. C, N, P, Fe). However, the organic matter itself is poorly characterized. Consequently, little is known about its relevance in driving biogeochemical processes that control U fate and transport in the subsurface. In an investigation of soil/sediment cores from five former uranium ore processing sites on floodplains distributed across the Upper Colorado River Basin we confirmed consistent co-enrichment of U with organic-rich layers in all profiles. However, using C K-edge X-ray Absorption Spectroscopy (XAS) coupled with Fourier-Transformed Ion-Cyclotron-Resonance Mass-Spectroscopy (FT-ICR-MS) on bulk sediments and density-separated organic matter fractions, we did not detect any chemical difference in the organic rich sediments compared to the surrounding coarser-grained aquifer material within the same profile, even though there were differences in organic matter composition between the 5 sites. This suggests that U retention and reduction to U(IV) is independent of C chemical composition on the bulk scale. Instead it appears to be the abundance of organic matter in combination with a limited O2 supply in the fine-grained material that stimulate anaerobic microbial processes responsible for U enrichment. Thus, the chemical composition of organic matter is subordinate to the physical environment and total organic matter content in controlling U reduction and retention processes.

Progressive enrichment of arc magmas caused by the subduction of seamounts under Nishinoshima volcano, Izu-Bonin Arc, Japan

NASA Astrophysics Data System (ADS)

Sano, Takashi; Shirao, Motomaro; Tani, Kenichiro; Tsutsumi, Yukiyasu; Kiyokawa, Shoichi; Fujii, Toshitsugu

2016-06-01

The chemical composition of intraplate seamounts is distinct from normal seafloor material, meaning that the subduction of seamounts at a convergent margin can cause a change in the chemistry of the mantle wedge and associated arc magmas. Nishinoshima, a volcanic island in the Izu-Bonin Arc of Japan, has been erupting continuously over the past 2 years, providing an ideal opportunity to examine the effect of seamount subduction on the chemistry of arc magmas. Our research is based on the whole-rock geochemistry and the chemistry of minerals within lavas and air-fall scoria from Nishinoshima that were erupted before 1702, in 1973-1974, and in 2014. The mineral phases within the analyzed samples crystallized under hydrous conditions (H2O = 3-4 wt.%) at temperatures of 970 °C-990 °C in a shallow (3-6 km depth) magma chamber. Trace element data indicate that the recently erupted Nishinoshima volcanics are much less depleted in the high field strength elements (Nb, Ta, Zr, Hf) than other volcanics within the Izu-Bonin Arc. In addition, the level of enrichment in the Nishinoshima magmas has increased in recent years, probably due to the addition of material from HIMU-enriched (i.e., high Nb/Zr and Ta/Hf) seamounts on the Pacific Plate, which is being subducted westwards beneath the Philippine Sea Plate. This suggests that the chemistry of scoria from Nishinoshima volcano records the progressive addition of components derived from subducted seamounts.

Physicochemical and sensorial characteristics of noodle enriched with oyster mushroom (Pleorotus ostreatus) powder

NASA Astrophysics Data System (ADS)

Wahyono, A.; Novianti; Bakri, A.; Kasutjianingati

2018-01-01

Oyster Mushroom is a mushroom that can be used for food and medicine. It contains highly nutritious and functional substances such as statins and beta-glucan. A comprehensive evaluation of noodle-enriched with Oyster Mushroom powder has not been performed so far. In this study, we performed a comprehensive evaluation of noodle-enriched with Oyster Mushroom powder. The aim of this study was to assess the effects of enrichment of Oyster Mushroom Powder (OMP) on the quality of noodle. The quality of noodle was evaluated based on physical, chemical and sensorial characteristics. This study was done by substituting wheat flour with OMP at the level of 0 (control); 5; 7.5; 10; 12.5; and 15%. The results showed that OMP significantly affected (P<0.05) the chemical, physical and sensorial quality of enriched noodles. Increased OMP level concurrently increased ash, crude fiber content and water activity (Aw) of resulting noodles. The enrichment was significantly raised the redness and yellowness of noodles, but decreased whiteness index. In addition, the enrichment of OMP significantly affected the sensorial properties of enriched noodles including color, taste, aroma and texture. OMP enrichment can be done at the level of 5% without compromising color, aroma, and texture of noodle, but 12.5% for taste attribute. Thus, OMP enrichment is feasible to enhance the nutritional values of noodle.

SIMS chemical analysis of extended impact features from the trailing edge portion of experiment AO187-2

NASA Technical Reports Server (NTRS)

Amari, Sachiko; Foote, John; Simon, Charles; Jessberger, Elmar K.; Lange, Gundolf; Stadermann, Frank; Swan, Pat; Walker, Robert M.; Zinner, Ernst

1992-01-01

One hundred capture cells from the trailing edge, which had lost their cover foils during flight, were optically scanned for extended impact features caused by high velocity projectiles impinging on the cells while the foils were still intact. Of the 53 candidates, 24 impacts were analyzed by secondary ion mass spectroscopy for the chemical composition of the deposits. Projectile material was found in all impacts, and at least 75 percent of them appear to be caused by interplanetary dust particles. Elemental ratios are fractionated, with refractory elements enriched in the impacts relative to interplanetary dust particles collected in the stratosphere. Although this could be due to systematic differences in the compositions, a more likely explanation is volatility fractionation during the impact process.

Determination of changes in the concentration and distribution of elements within olive drupes (cv. Leccino) from Se biofortified plants, using laser ablation inductively coupled plasma mass spectrometry.

PubMed

D'Amato, Roberto; Petrelli, Maurizio; Proietti, Primo; Onofri, Andrea; Regni, Luca; Perugini, Diego; Businelli, Daniela

2018-03-25

Biofortification of food crops has been used to increase the intake of Se in the human diet, even though this may change the concentration of other elements and modify the nutritional properties of the enriched food. Selenium biofortification programs should include routine assessment of the overall mineral composition of enriched plants. Laser ablation inductively coupled plasma mass spectrometry (LA ICP-MS) was used for the assessment of mineral composition of table olives. Olive trees were fertilized with sodium selenate before flowering. At harvest, the edible parts of drupes proved to be significantly enriched in Se, delivering 6.1 μg g -1 (39% of the RDA for five olives). Such enrichment was followed by significant changes in the concentrations of B, Mg, K, Cr, Mn, Fe and Cu in edible parts, which are discussed for their impact on food quality. The biofortification of olive plants has allowed the enrichment of fruits with selenium. Enrichment with selenium has caused an increase in the concentration of other elements, which can change the nutritional quality of the drupes. The analytical technique used well as a valuable tool for routinely determining the chemical composition of all fruit parts. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Reexamining Content-Enriched Access: Its Effect on Usage and Discovery

ERIC Educational Resources Information Center

Tosaka, Yuji; Weng, Cathy

2011-01-01

Content-enriched metadata in bibliographic records is considered helpful to library users in identifying and selecting library materials for their needs. The paper presents a study, using circulation data from a medium-sized academic library, of the effect of content-enriched records on library materials usage. The study also examines OPAC search…

75 FR 60485 - NRC Enforcement Policy Revision

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-30

... centrifuge or laser enrichment facilities. The NRC has issued licenses for two gas centrifuge uranium... significance)). In addition, the radiological and chemical risks of gas centrifuge uranium enrichment...

One-step chemical vapor deposition synthesis and supercapacitor performance of nitrogen-doped porous carbon–carbon nanotube hybrids

PubMed Central

Bulusheva, Lyubov G; Fedorovskaya, Ekaterina O; Shubin, Yury V; Plyusnin, Pavel E; Lonchambon, Pierre; Senkovskiy, Boris V; Ismagilov, Zinfer R; Flahaut, Emmanuel; Okotrub, Alexander V

2017-01-01

Novel nitrogen-doped carbon hybrid materials consisting of multiwalled nanotubes and porous graphitic layers have been produced by chemical vapor deposition over magnesium-oxide-supported metal catalysts. CNx nanotubes were grown on Co/Mo, Ni/Mo, or Fe/Mo alloy nanoparticles, and MgO grains served as a template for the porous carbon. The simultaneous formation of morphologically different carbon structures was due to the slow activation of catalysts for the nanotube growth in a carbon-containing gas environment. An analysis of the obtained products by means of transmission electron microscopy, thermogravimetry and X-ray photoelectron spectroscopy methods revealed that the catalyst's composition influences the nanotube/porous carbon ratio and concentration of incorporated nitrogen. The hybrid materials were tested as electrodes in a 1M H2SO4 electrolyte and the best performance was found for a nitrogen-enriched material produced using the Fe/Mo catalyst. From the electrochemical impedance spectroscopy data, it was concluded that the nitrogen doping reduces the resistance at the carbon surface/electrolyte interface and the nanotubes permeating the porous carbon provide fast charge transport in the cell. PMID:29354339

Spectroscopic study of nitrogen distribution in N-doped carbon nanotubes and nanofibers synthesized by catalytic ethylene-ammonia decomposition

NASA Astrophysics Data System (ADS)

Svintsitskiy, Dmitry A.; Kibis, Lidiya S.; Smirnov, Dmitry A.; Suboch, Arina N.; Stonkus, Olga A.; Podyacheva, Olga Yu.; Boronin, Andrei I.; Ismagilov, Zinfer R.

2018-03-01

Carbon and nitrogen species on the surface of carbon nanotubes (N-CNTs) and nanofibers (N-CNFs) were studied by X-ray absorption (XAS) and photoelectron spectroscopy (PES) including the analysis of nitrogen distribution over the depth of materials. The study was performed with a series of bamboo-like carbon nanotubes and nanofibers having the platelet-like and herringbone-like morphology. It was shown that the main nitrogen species in the composition of the studied materials are pyridine, pyrrole (and/or amino groups), graphite-like and oxidized states of nitrogen. In distinction to nanofibers, the bamboo-like nanotubes additionally contain molecular nitrogen encapsulated in the internal hollows. Spectral data for different depths of analysis were obtained by varying the energy of incident radiation. Such an approach revealed that N-CNTs are characterized by non-uniform distribution of chemically bound nitrogen species. Thus, nitrogen enrichment was observed on the external surface and in the internal arches of carbon nanotubes. Nitrogen enrichment in the subsurface region was found for N-CNFs, whereas the full depth analysis of N-distribution was limited by a large diameter of nanofibers.

NiFe nanoparticles: a soft magnetic material?

PubMed

Margeat, Olivier; Ciuculescu, Diana; Lecante, Pierre; Respaud, Marc; Amiens, Catherine; Chaudret, Bruno

2007-03-01

Polytetrahedral NiFe nanoparticles with diameters of (2.8+/-0.3) nm have been obtained by hydrogenation of Ni[(COD)(2)] (COD=1,5-cyclooctadiene) and Fe[{N(SiMe(3))(2)}(2)] at 150 degrees C using stearic acid and hexadecylamine as stabilizing ligands. The nanoparticles are superparamagnetic at room temperature and display a blocking temperature of 17.6 K. Their anisotropy (2.7x10(5)J m(-3)) is determined to be more than two orders of magnitude higher than that of the bulk NiFe alloy (10(3)J m(-3)) and is close to that determined for Fe nanoparticles of the same size. Still, they display a magnetization of (1.69+/-0.05) mu(B) per metallic atom, identical to that of the bulk NiFe alloy. Combining the results from X-ray absorption and Mössbauer studies, we evidence a progressive enrichment in iron atoms from the core to the surface of the nanoparticles. These results are discussed in relation to both size and chemical effects. They show the main role played by the enriched Fe surface on the magnetic properties and address the feasibility of soft magnetic materials at the nanoscale.

Consequences of enriched atmospheric CO{sub 2} and defoliation for foliar chemistry and gypsy moth performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindroth, R.L.; Kinney, K.K.

1998-10-01

Elevated concentrations of atmospheric CO{sub 2} are likely to interact with other factors affecting plant physiology to alter plant chemical profiles and plant-herbivore interactions. The authors evaluated the independent and interactive effects of enriched CO{sub 2} and artificial defoliation on foliar chemistry of quaking aspen (Populus tremuloides) and sugar maple (Acer saccharum), and the consequences of such changes for short-term performance of the gypsy moth (Lymantria dispar). They grew aspen and maple seedlings in ambient and enriched CO{sub 2} environments at the University of wisconsin Biotron. Seven weeks after budbreak, trees in half of the rooms were subjected to 50%more » defoliation. Afterwards, foliage was collected for chemical analyses, and feeding trials were conducted with fourth-stadium gypsy moths. Enriched CO{sub 2} altered foliar levels of water, nitrogen, carbohydrates, and phenolics, and responses generally differed between the two tree species. Defoliation induced chemical changes only in aspen. They found no significant interactions between CO{sub 2} and defoliation for levels of carbon-based defenses (phenolic glycosides and tannins). CO{sub 2} treatment altered the performance of larvae fed aspen, but not maple, whereas defoliation had little effect on performance on insects. In general, results from this experimental system do not support the hypothesis that induction of carbon-based chemical defenses, and attendant effects on insects, will be stronger in a CO{sub 2}-enriched world.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boussaa, S. Anas, E-mail: sabiha.anas@gmail.com; Kheloufi, A.; Kefaifi, A.

Raw materials are essential for the functioning of modern societies, and access to these raw materials is vital to the world economy. Sustainable development, both globally level, raises important new challenges associated with access and efficient use of raw materials. High purity quartz, is consider as a critical raw material and it is a rare commodity that only forms under geological conditions where a narrow set of chemical and physical parameters is fulfilled. When identified and following special beneficiation techniques, high purity quartz obtains very attractive prices and is applied in high technology sectors that currently are under rapid expansionmore » such as photovoltaic solar cells, silicon metal - oxide wafers in the semiconductor industry and long distance optical fibers that are used in communication networks. Crystalline silicon remains the principal material for photovoltaic technology. Metallurgical silicon is produced industrially by the reduction of silica with carbon in an electric arc furnace at temperatures higher than 2000 °C in the hottest parts, by a reaction that can be written ideally as: SiO{sub 2} + 2C = Si + 2CO. The aim of this study has been to test experimental methods for investigating the various physical and chemical proprieties of Hoggar quartz with different techniques: X Ray Fluorescence, infra-red spectroscopy, Scanning Electron Microscopy, Optic Microscopy, Carbon Analyzer and Vickers Hardness. The results show finally that the quartz has got good result in purity but need enrichment for the photovoltaic application.« less

Nitrogen-enriched hierarchically porous carbons prepared from polybenzoxazine for high-performance supercapacitors.

PubMed

Wan, Liu; Wang, Jianlong; Xie, Lijing; Sun, Yahui; Li, Kaixi

2014-09-10

Nitrogen-enriched hierarchically porous carbons (HPCs) were synthesized from a novel nitrile-functionalized benzoxazine based on benzoxazine chemistry using a soft-templating method and a potassium hydroxide (KOH) chemical activation method and used as electrode materials for supercapacitors. The textural and chemical properties could be easily tuned by adding a soft template and changing the activation temperature. The introduction of the soft-templating agent (surfactant F127) resulted in the formation of mesopores, which facilitated fast ionic diffusion and reduced the internal resistance. The micropores of HPCs were extensively developed by KOH activation to provide large electrochemical double-layer capacitance. As the activation temperature increased from 600 to 800 °C, the specific surface area of nitrogen-enriched carbons increased dramatically, micropores were enlarged, and more meso/macropores were developed, but the nitrogen and oxygen content decreased, which affected the electrochemical performance. The sample HPC-800 activated at 800 °C possesses a high specific surface area (1555.4 m(2) g(-1)), high oxygen (10.61 wt %) and nitrogen (3.64 wt %) contents, a hierarchical pore structure, a high graphitization degree, and good electrical conductivity. It shows great pseudocapacitance and the largest specific capacitance of 641.6 F g(-1) at a current density of 1 A g(-1) in a 6 mol L(-1) KOH aqueous electrolyte when measured in a three-electrode system. Furthermore, the HPC-800 electrode exhibits excellent rate capability (443.0 F g(-1) remained at 40 A g(-1)) and good cycling stability (94.3% capacitance retention over 5000 cycles).

Cometary coma chemical composition (C4) mission. [Abstract only

NASA Technical Reports Server (NTRS)

Carle, G. C.; Clark, B. C.; Niemann, H. B.; Alexander, M.; Knocke, P. C.; O'Hara, B. J.

1994-01-01

Cometary missions are of enormous fundamental importance for many different space science disciplines, including exobiology. Comets are presumed relics of the earliest, most primitive material in the solar nebula and are related to the planetesimals. They undoubtedly provided a general enrichment of volatiles to the inner solar system (contributing to atmospheres and oceans) and may have been key to the origin of life. A Discovery class, comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, was selected for further study by NASA earlier this year. The C4 Mission is a highly focused and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission, concentrating exclusively on measurements which will lead to an understanding of the chemical composition and make-up of the cometary nucleus. The scientific goals of the Cometary Coma Chemical Composition (C4) Mission are to rendezvous with a short-period comet and (1) to determine the elemental, chemical, and isotopic composition of the nucleus and (2) to characterize the chemical and isotopic nature of its atmosphere. Further, it is a goal to obtain preliminary data on the development of the coma (dust and gas composition) as a function of time and orbital position.

10 CFR 74.33 - Nuclear material control and accounting for uranium enrichment facilities authorized to produce...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false Nuclear material control and accounting for uranium enrichment facilities authorized to produce special nuclear material of low strategic significance. 74.33 Section 74.33 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) MATERIAL CONTROL AND ACCOUNTING OF SPECIAL...

10 CFR 74.33 - Nuclear material control and accounting for uranium enrichment facilities authorized to produce...

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false Nuclear material control and accounting for uranium enrichment facilities authorized to produce special nuclear material of low strategic significance. 74.33 Section 74.33 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) MATERIAL CONTROL AND ACCOUNTING OF SPECIAL...

10 CFR 74.33 - Nuclear material control and accounting for uranium enrichment facilities authorized to produce...

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false Nuclear material control and accounting for uranium enrichment facilities authorized to produce special nuclear material of low strategic significance. 74.33 Section 74.33 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) MATERIAL CONTROL AND ACCOUNTING OF SPECIAL...

Multiple Cosmic Sources for Meteorite Macromolecules?

PubMed Central

Watson, Jonathan S.; Meredith, William; Love, Gordon D.; Gilmour, Iain; Snape, Colin E.

2015-01-01

Abstract The major organic component in carbonaceous meteorites is an organic macromolecular material. The Murchison macromolecular material comprises aromatic units connected by aliphatic and heteroatom-containing linkages or occluded within the wider structure. The macromolecular material source environment remains elusive. Traditionally, attempts to determine source have strived to identify a single environment. Here, we apply a highly efficient hydrogenolysis method to liberate units from the macromolecular material and use mass spectrometric techniques to determine their chemical structures and individual stable carbon isotope ratios. We confirm that the macromolecular material comprises a labile fraction with small aromatic units enriched in 13C and a refractory fraction made up of large aromatic units depleted in 13C. Our findings suggest that the macromolecular material may be derived from at least two separate environments. Compound-specific carbon isotope trends for aromatic compounds with carbon number may reflect mixing of the two sources. The story of the quantitatively dominant macromolecular material in meteorites appears to be made up of more than one chapter. Key Words: Abiotic organic synthesis—Carbonaceous chondrite—Cosmochemistry—Meteorites. Astrobiology 15, 779–786. PMID:26418568

Chemical Evolution of Presolar Organics in Astromaterials

NASA Technical Reports Server (NTRS)

Nakamura-Messenger, K.; Clemett, S. J.; Messenger, Scott; Keller, L. P.

2010-01-01

Sub-micron, hollow organic globules reported from several carbonaceous chondrites, interplanetary dust particles, and comet Wild-2 samples returned by NASA?s Stardust mission are enriched in N-15/N-14 and D/H compared with terrestrial materials and the parent materials [1-4]. These anomalies are ascribed to the preservation of presolar cold molecular cloud material from where H, C, and N isotopic constraints point to chemical fractionation near 10 K [5]. An origin well beyond the planet forming region and their survival in meteorites suggests submicrometer organic globules were once prevalent throughout the solar nebula. The survival of the membrane structures indicates primitive meteorites and cometary dust particles would have delivered these organic precursors to the early Earth as well as other planets and satellites. The physical, chemical, and isotopic properties of the organic globules varies to its meteorite types and its lithologies. For example, organic globules in the Tagish Lake meteorite are always embedded in fined grained (poorly crystallized) saponite, and hardly encapsulated in coarse grained serpentine, even though saponite and serpentine are both main components of phyllosilicate matrix of the Tagish Lake meteorite. The organic globules are commonly observed in the carbonate-poor lithology but not in the carbonate-rich one. In Tagish Lake, isolated single globules are common, but in the Bells (CM2) meteorite, globules are mostly aggregated. We will review the evolutions of the organic globules from its birth to alteration in the parent bodies in terms of its own physical and chemical properties as well as its associated minerals.

Chemical projectile-target interaction during hypervelocity cratering experiments (MEMIN project).

NASA Astrophysics Data System (ADS)

Ebert, M.; Hecht, L.; Deutsch, A.; Kenkmann, T.

2012-04-01

The detection and identification of meteoritic components in impact-derived rocks are of great value for confirming an impact origin and reconstructing the type of extraterrestrial material that repeatedly stroke the Earth during geologic evolution [1]. However, little is known about processes that control the projectile distribution into the various impactites that originate during the cratering and excavation process, and inter-element fractionation between siderophile elements during impact cratering. In the context of the MEMIN project, cratering experiments have been performed using spheres of Cr-V-Co-Mo-W-rich steel and of the iron meteorite Campo del Cielo (IAB) as projectiles accelerated to about 5 km/s, and blocks of Seeberger sandstone as target. The experiments were carried out at the two-stage acceleration facilities of the Fraunhofer Ernst-Mach-Institute (Freiburg). Our results are based on geochemical analyses of highly shocked ejecta material. The ejecta show various shock features including multiple sets of planar deformations features (PDF) in quartz, diaplectic quartz, and partial melting of the sandstone. Melting is concentrated in the phyllosilicate-bearing sandstone matrix but involves quartz, too. Droplets of molten projectile have entered the low-viscosity sandstone melt but not quartz glass. Silica-rich sandstone melts are enriched in the elements that are used to trace the projectile, like Fe, Ni, Cr, Co, and V (but no or little W and Mo). Inter-element ratios of these "projectile" tracer elements within the contaminated sandstone melt may be strongly modified from the original ratios in the projectiles. This fractionation most likely result from variation in the lithophile or siderophile character and/or from differences in reactivity of these tracer elements with oxygen [2] during interaction of metal melt with silicate melt. The shocked quartz with PDF is also enriched in Fe and Ni (experiment with a meteorite iron projectile) and in Fe, Cr, Co and V (experiment with the steel projectile). An enrichment of W and Mo in the shocked quartzes could not be observed. It is suggested that two types of geochemical mixing processes between projectile and target occur during the impact process: (i) After shock compression with formation of PDF in Qtz and diaplectic quartz glass, up to about 1 % of projectile matter is added to these phases without detectable fractionation between the meteoritic tracer elements (except W and Mo). We suggest that projectile material was introduced to shocked quartz from a metallic vapour phase, which was formed near the projectile-target interface. The lack of W and Mo enrichment in shocked target material probably results from the relatively high melting and boiling points of these elements. (ii) In addition heterogeneous melting of sandstone and projectile and subsequent mixing of both melts inter-element fractionation occurred according to the chemical properties of the elements. Fractionation processes similar to our type (ii) are known from natural impactites [3]. We acknowledge support by the German Science Foundation (DFG FOR 887)

77 FR 14838 - General Electric-Hitachi Global Laser Enrichment LLC, Commercial Laser-Based Uranium Enrichment...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-13

... safety, chemical process safety, fire safety, emergency management, environmental protection... the transportation of SNM of low strategic significance, human factors engineering, and electrical...

16O enrichments in aluminum-rich chondrules from ordinary chondrites

NASA Astrophysics Data System (ADS)

Russell, Sara S.; MacPherson, Glenn J.; Leshin, Laurie A.; McKeegan, Kevin D.

2000-12-01

The oxygen isotopic compositions of seven Al-rich chondrules from four unequilibrated ordinary chondrites were measured in situ using an ion microprobe. On an oxygen three isotope plot, the data are continuous with the ordinary chondrite ferromagnesian chondrule field but extend it to more 16O-enriched values along a mixing line of slope=0.83±0.09, with the lightest value recorded at δ18O=-15.7±1.8‰ and δ17O=-13.5±2.6‰. If Al-rich chondrules were mixtures of ferromagnesian chondrules and CAI material, their bulk chemical compositions would require them to exhibit larger 16O enrichments than we observe. Therefore, Al-rich chondrules are not simple mixtures of these two components. Three chondrules exhibit significant internal isotopic heterogeneity indicative of partial exchange with a gaseous reservoir. Porphyritic Al-rich chondrules are consistently 16O-rich relative to nonporphyritic ones, suggesting that degree of melting is a key factor and pointing to a nebular setting for the isotopic exchange process. Because Al-rich chondrules are closely related to ferromagnesian chondrules, their radiogenic Mg isotopic abundances can plausibly be applied to help constrain the timing or location of chondrule formation.

Mixing in heterogeneous internally-heated convection

NASA Astrophysics Data System (ADS)

Limare, A.; Kaminski, E. C.; Jaupart, C. P.; Farnetani, C. G.; Fourel, L.; Froment, M.

2017-12-01

Past laboratory experiments of thermo chemical convection have dealt with systems involving fluids with different intrinsic densities and viscosities in a Rayleigh-Bénard setup. Although these experiments have greatly improved our understanding of the Earth's mantle dynamics, they neglect a fundamental component of planetary convection: internal heat sources. We have developed a microwave-based method in order to study convection and mixing in systems involving two layers of fluid with different densities, viscosities, and internal heat production rates. Our innovative laboratory experiments are appropriate for the early Earth, when the lowermost mantle was likely enriched in incompatible and heat producing elements and when the heat flux from the core probably accounted for a small fraction of the mantle heat budget. They are also relevant to the present-day mantle if one considers that radioactive decay and secular cooling contribute both to internal heating. Our goal is to quantify how two fluid layers mix, which is still very difficult to resolve accurately in 3-D numerical calculations. Viscosities and microwave absorptions are tuned to achieve high values of the Rayleigh-Roberts and Prandtl numbers relevant for planetary convection. We start from a stably stratified system where the lower layer has higher internal heat production and density than the upper layer. Due to mixing, the amount of enriched material gradually decreases to zero over a finite time called the lifetime. Based on more than 30 experiments, we have derived a scaling law that relates the lifetime of an enriched reservoir to the layer thickness ratio, a, to the density and viscosity contrasts between the two layers, and to their two different internal heating rates in the form of an enrichment factor beta=1+2*a*H1/H, where H1 is the heating rate of the lower fluid and H is the average heating rate. We find that the lifetime of the lower enriched reservoir varies as beta**(-7/3) in the low viscosity contrast limit, and as beta**(-4/3) in the large viscosity contrast limit. Our state-of-the-art experimental technique thus provides insights on chemical differentiation processes and on the evolution of mantle heterogeneities on both short and long time-scales.

15N fractionation in star-forming regions and Solar System objects

NASA Astrophysics Data System (ADS)

Wirström, Eva; Milam, Stefanie; Adande, Gilles; Charnley, Steven B.; Cordiner, Martin A.

2015-08-01

A central issue for understanding the formation and evolution of matter in the early Solar System is the relationship between the chemical composition of star-forming interstellar clouds and that of primitive Solar System materials. The pristine molecular content of comets, interplanetary dust particles and carbonaceous chondrites show significant bulk nitrogen isotopic fractionation relative to the solar value, 14N/15N ~ 440. In addition, high spatial resolution measurements in primitive materials locally show even more extreme enhancements of 14N/15N < 100.The coherent 15N enrichment in comets from different formation zones suggests that these isotopic enhancements are remnants of the interstellar chemistry in the natal molecular cloud core and the outer protosolar nebula. Indeed, early chemical models of gas-phase ion-molecule nitrogen fractionation showed that HCN and HNC (nitriles) can hold significant 15N enrichments in cold dark clouds where CO is depleted onto dust grains. In addition, 15N fractionation in nitriles and amines (NH2, NH3) follow different chemical pathways. More recently we have shown that once the spin-state dependence in rates of reactions with H2 is included in the models, amines can either be enhanced or depleted in 15N, depending on the core’s evolutionary stage. Observed 15N fractionation in amines and nitriles therefore cannot be expected to be the same, instead their ratio is a potential chemical clock.Observations of molecular isotope ratios in dark cores are challenging. Limited published results in general show higher 15N/14N ratios in HCN and HNC than ammonia, but more measurements are necessary to confirm these trends. We will present recent results from our ongoing observing campaign of 14N/15N isotopic ratios in HCN, HNC and NH3 in dense cores and protostars which seem consistent with significant fractionation in nitriles as compared to other molecules in each object. The few 14N/15N ratios observed in N2H+ are similar to those in NH3, contrary to our model results which predict a significant 15N enhancement in N2 and N2H+. Model upgrades which may address this discrepancy will be presented and discussed.

Detection of thermal-induced prompt fission neutrons of highly-enriched uranium: A position sensitive technique

NASA Astrophysics Data System (ADS)

Tartaglione, A.; Di Lorenzo, F.; Mayer, R. E.

2009-07-01

Cargo interrogation in search for special nuclear materials like highly-enriched uranium or 239Pu is a first priority issue of international borders security. In this work we present a thermal-pulsed neutron-based approach to a technique which combines the time-of-flight method and demonstrates a capability to detect small quantities of highly-enriched uranium shielded with high or low Z materials providing, in addition, a manner to know the approximate position of the searched material.

Onsite Gaseous Centrifuge Enrichment Plant UF6 Cylinder Destructive Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anheier, Norman C.; Cannon, Bret D.; Qiao, Hong

2012-07-17

The IAEA safeguards approach for gaseous centrifuge enrichment plants (GCEPs) includes measurements of gross, partial, and bias defects in a statistical sampling plan. These safeguard methods consist principally of mass and enrichment nondestructive assay (NDA) verification. Destructive assay (DA) samples are collected from a limited number of cylinders for high precision offsite mass spectrometer analysis. DA is typically used to quantify bias defects in the GCEP material balance. Under current safeguards measures, the operator collects a DA sample from a sample tap following homogenization. The sample is collected in a small UF6 sample bottle, then sealed and shipped under IAEAmore » chain of custody to an offsite analytical laboratory. Current practice is expensive and resource intensive. We propose a new and novel approach for performing onsite gaseous UF6 DA analysis that provides rapid and accurate assessment of enrichment bias defects. DA samples are collected using a custom sampling device attached to a conventional sample tap. A few micrograms of gaseous UF6 is chemically adsorbed onto a sampling coupon in a matter of minutes. The collected DA sample is then analyzed onsite using Laser Ablation Absorption Ratio Spectrometry-Destructive Assay (LAARS-DA). DA results are determined in a matter of minutes at sufficient accuracy to support reliable bias defect conclusions, while greatly reducing DA sample volume, analysis time, and cost.« less

Uniform Contribution of Supernova Explosions to the Chemical Enrichment of Abell 3112 out to R{sub 200}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ezer, Cemile; Ercan, E. Nihal; Bulbul, Esra

2017-02-10

The spatial distribution of the metals residing in the intra-cluster medium (ICM) of galaxy clusters records all the information on a cluster’s nucleosynthesis and chemical enrichment history. We present measurements from a total of 1.2 Ms Suzaku XIS and 72 ks Chandra observations of the cool-core galaxy cluster Abell 3112 out to its virial radius (∼1470 kpc). We find that the ratio of the observed supernova type Ia explosions to the total supernova explosions has a uniform distribution at a level of 12%–16% out to the cluster’s virial radius. The observed fraction of type Ia supernova explosions is in agreementmore » with the corresponding fraction found in our Galaxy and the chemical enrichment of our Galaxy. The non-varying supernova enrichment suggests that the ICM in cluster outskirts was enriched by metals at an early stage before the cluster itself was formed during a period of intense star formation activity. Additionally, we find that the 2D delayed detonation model CDDT produce significantly worse fits to the X-ray spectra compared to simple 1D W7 models. This is due to the relative overestimate of Si, and the underestimate of Mg in these models with respect to the measured abundances.« less

Origin of central abundances in the hot intra-cluster medium. II. Chemical enrichment and supernova yield models

NASA Astrophysics Data System (ADS)

Mernier, F.; de Plaa, J.; Pinto, C.; Kaastra, J. S.; Kosec, P.; Zhang, Y.-Y.; Mao, J.; Werner, N.; Pols, O. R.; Vink, J.

2016-11-01

The hot intra-cluster medium (ICM) is rich in metals, which are synthesised by supernovae (SNe) and accumulate over time into the deep gravitational potential well of clusters of galaxies. Since most of the elements visible in X-rays are formed by type Ia (SNIa) and/or core-collapse (SNcc) supernovae, measuring their abundances gives us direct information on the nucleosynthesis products of billions of SNe since the epoch of the star formation peak (z 2-3). In this study, we compare the most accurate average X/Fe abundance ratios (compiled in a previous work from XMM-Newton EPIC and RGS observations of 44 galaxy clusters, groups, and ellipticals), representative of the chemical enrichment in the nearby ICM, to various SNIa and SNcc nucleosynthesis models found in the literature. The use of a SNcc model combined to any favoured standard SNIa model (deflagration or delayed-detonation) fails to reproduce our abundance pattern. In particular, the Ca/Fe and Ni/Fe ratios are significantly underestimated by the models. We show that the Ca/Fe ratio can be reproduced better, either by taking a SNIa delayed-detonation model that matches the observations of the Tycho supernova remnant, or by adding a contribution from the "Ca-rich gap transient" SNe, whose material should easily mix into the hot ICM. On the other hand, the Ni/Fe ratio can be reproduced better by assuming that both deflagration and delayed-detonation SNIa contribute in similar proportions to the ICM enrichment. In either case, the fraction of SNIa over the total number of SNe (SNIa+SNcc) contributing to the ICM enrichment ranges within 29-45%. This fraction is found to be systematically higher than the corresponding SNIa/(SNIa+SNcc) fraction contributing to the enrichment of the proto-solar environnement (15-25%). We also discuss and quantify two useful constraints on both SNIa (I.e. the initial metallicity on SNIa progenitors and the fraction of low-mass stars that result in SNIa) and SNcc (I.e. the effect of the IMF and the possible contribution of pair-instability SNe to the enrichment) that can be inferred from the ICM abundance ratios. Finally, we show that detonative sub-Chandrasekhar WD explosions (resulting, for example, from violent WD mergers) cannot be a dominant channel for SNIa progenitors in galaxy clusters.

A shear localization mechanism for lubricity of amorphous carbon materials

PubMed Central

Ma, Tian-Bao; Wang, Lin-Feng; Hu, Yuan-Zhong; Li, Xin; Wang, Hui

2014-01-01

Amorphous carbon is one of the most lubricious materials known, but the mechanism is not well understood. It is counterintuitive that such a strong covalent solid could exhibit exceptional lubricity. A prevailing view is that lubricity of amorphous carbon results from chemical passivation of dangling bonds on surfaces. Here we show instead that lubricity arises from shear induced strain localization, which, instead of homogeneous deformation, dominates the shearing process. Shear localization is characterized by covalent bond reorientation, phase transformation and structural ordering preferentially in a localized region, namely tribolayer, resulting in shear weakening. We further demonstrate an anomalous pressure induced transition from stick-slip friction to continuous sliding with ultralow friction, due to gradual clustering and layering of graphitic sheets in the tribolayer. The proposed shear localization mechanism sheds light on the mechanism of superlubricity, and would enrich our understanding of lubrication mechanism of a wide variety of amorphous materials. PMID:24412998

Dust, Abundances, and the Evolution of Novae

NASA Astrophysics Data System (ADS)

Woodward, Charles; Bode, Michael; Evans, Anuerin; Geballe, Thomas; Gehrz, Robert; Helton, Andrew; Krautter, Joachim; Lynch, David; Ness, Jan-Uwe; Rudy, Richard; Schwarz, Greg; Shore, Steve; Starrfield, Sumner; Truran, James; Vanlandingham, Karen; Wagner, R. Mark

2008-03-01

Evolved stars are the engines of energy production and chemical evolution in our Universe. They deposit radiative and mechanical energy into their environments. They enrich the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CNe) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. Our capstone study of 10 CNe will provide an ensemble of objects, well-populated in CNe parameter space (fast, slow, 'coronal', dusty) for detailed photoionization modeling and analysis. CNe are laboratories in which several poorly-understood astrophysical processes (e.g., mass transfer, thermonuclear runaway, optically thick winds, common envelope evolution, molecule and grain formation, coronal emission) may be observed. With Spitzer's unique wavelength coverage and point-source sensitivity we can: (i) investigate the in situ formation, astromineralogy, and processing of nova dust, (ii) determine the ejecta elemental abundances resulting from thermonuclear runaway, (iii) constrain the correlation of ejecta mass with progenitor type, (iv) measure the bolometric luminosity of the outburst, and (v) characterize the kinematics and structure of the ejected envelopes. Extensive ground-based and space-based (Chandra, Swift, XMM-Newton) programs led by team CoIs will complement Spitzer CNe observations.

Transcriptomic analysis on responses of the liver and kidney of finishing pigs fed cadmium contaminated rice.

PubMed

Xia, Yaoyao; Li, Jun; Ren, Wenkai; Feng, Zemeng; Huang, Ruilin; Yin, Yulong

2018-06-01

Cadmium (Cd) is a common harmful substance that has many deleterious effects on the liver and kidney. Most reports about Cd toxic studies focused on its inorganic status, whereas the toxicity of Cd in organic materials is less studied. Here, we performed RNA-seq to explore the influences of Cd contaminated rice on function of the liver and kidney of finishing pigs. The concentration of Cd in liver and kidney of pigs fed Cd contaminated rice increased by 4.00 and 2.94 times, respectively, compared to those in the control group. With transcriptomic analysis, approximately 4-6 × 10 7 clean reads were acquired. Five differently expressed genes (DEGs) were identified in the liver, and 12 DEGs in the kidney. SPHK2 was commonly down-regulated. No significantly enriched gene ontology (GO) terms were identified. By Kyoto encyclopaedia of genes and genomes (KEGG) enrichments, four pathways were identified in hepatic tissue, and five pathways in nephritic tissue. Intriguingly, two pathways (sphingolipid metabolism and VEGF signalling pathway) were altered both in the liver and kidney. Cd contaminated rice may cause liver and kidney damage and inflammation, or even lead to more severe harm to these tissues. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Lignin-carbohydrate complexes from sisal (Agave sisalana) and abaca (Musa textilis): chemical composition and structural modifications during the isolation process.

PubMed

Del Río, José C; Prinsen, Pepijn; Cadena, Edith M; Martínez, Ángel T; Gutiérrez, Ana; Rencoret, Jorge

2016-05-01

Two types of lignins occurred in different lignin-carbohydrate fractions, a lignin enriched in syringyl units, less condensed, preferentially associated with xylans, and a lignin with more guaiacyl units, more condensed, associated with glucans. Lignin-carbohydrate complexes (LCC) were isolated from the fibers of sisal (Agave sisalana) and abaca (Musa textilis) according to a plant biomass fractionation procedure recently developed and which was termed as "universally" applicable to any type of lignocellulosic material. Two LCC fractions, namely glucan-lignin (GL) and xylan-lignin (XL), were isolated and differed in the content and composition of carbohydrates and lignin. In both cases, GL fractions were enriched in glucans and comparatively depleted in lignin, whereas XL fractions were depleted in glucans, but enriched in xylans and lignin. Analysis by two-dimensional Nuclear Magnetic Resonance (2D-NMR) and Derivatization Followed by Reductive Cleavage (DFRC) indicated that the XL fractions were enriched in syringyl (S)-lignin units and β-O-4' alkyl-aryl ether linkages, whereas GL fractions have more guaiacyl (G)-lignin units and less β-O-4' alkyl-aryl ether linkages per lignin unit. The data suggest that the structural characteristics of the lignin polymers are not homogeneously distributed within the same plant and that two different lignin polymers with different composition and structure might be present. The analyses also suggested that acetates from hemicelluloses and the acyl groups (acetates and p-coumarates) attached to the γ-OH of the lignin side chains were extensively hydrolyzed and removed during the LCC fractionation process. Therefore, caution must be paid when using this fractionation approach for the structural characterization of plants with acylated hemicelluloses and lignins. Finally, several chemical linkages (phenylglycosides and benzyl ethers) could be observed to occur between lignin and xylans in these plants.

The Organic Content of the Tagish Lake Meteorite

NASA Technical Reports Server (NTRS)

Pizzarello, Sandra; Huang, Yongsong; Becker, Luann; Poreda, Robert J.; Nieman, Ronald A.; Cooper, George; Williams, Michael

2001-01-01

The Tagish Lake meteorite felt last year on a frozen take in Canada and may provide the most pristine material of its kind. Analyses have now shown this carbonaceous chondrite to contain a suite of soluble organic compounds (approximately 100 parts per million) that includes mono- and dicarboxylic acids, dicarboximides, pyridine carboxylic acids, a sulfonic acid, and both aliphatic and aromatic hydrocarbons. The insoluble carbon exhibits exclusive aromatic character, deuterium enrichment, and fullerenes containing 'planetary' helium and argon. The findings provide insight into an outcome of early solar chemical evolution that differs from any seen so far in meteorites.

Coatings on Atacama Desert Basalt: A Possible Analog for Coatings on Gusev Plains Basalt

NASA Technical Reports Server (NTRS)

Sutter, B.; Golden, D. C.; Amundson, R.; Chong-Diaz, G.; Ming, D. W.

2007-01-01

Surface coatings on Gusev Plains basalt have been observed and may contain hematite and nanophase Fe-oxides along with enrichments in P, S, Cl, and K relative to the underlying rock. The Gusev coatings may be derived from the dissolution of adhering soil and/or parent rock along with the addition of S and Cl from outside sources. Transient water for dissolution could be sourced from melting snow during periods of high obliquity, acid fog, and/or ground water (Haskin et al., 2005). Coatings on basalt in the hyper-arid (less than 2mm y(sup -1)) Atacama Desert may assist in understanding the chemistry, mineralogy and formation mechanisms of the Gusev basalt coatings. The Atacama Desert climate is proposed to be analogous to a paleo-Mars climate that was characterized by limited aqueous activity when the Gusev coatings could have formed. The objectives of this work are to (i) determine the chemical nature and extent of surface coatings on Atacama Desert basalt, and (ii) assess coating formation mechanisms in the Atacama Desert. Preliminary backscattered electron imaging of Atacama basalt thin-sections indicated that the coatings are as thick as 20 m. The boundary between the coating and the basalt labradorite, ilmenite, and augite grains was abrupt indicating that the basalt minerals underwent no chemical dissolution. The Atacama coatings have been added to the basalt instead of being derived from basalt chemical weathering. Semi-quantitative energy dispersive spectroscopy shows the coatings to be chemically homogeneous. The coating is depleted in Ca (0.9 wt% CaO) and enriched in K (1.3 wt.% K2O) and Si (69.1 wt.% SiO2) relative to the augite and labradorite grains. A dust source enriched in Si (e.g., poorly crystalline silica) and K and depleted in Ca appears to have been added to the basalt surface. Unlike the Gusev coatings, no P, S, and Cl enrichment was observed. However, Fe (3.2 wt.% FeO) was present in the Atacama coatings suggesting the present of Fe-oxides. While the chemistry of Atacama coating does not mirror the Gusev coating, the coating formation mechanism may be similar. The Atacama coatings of surface basalt are derived completely from exogenous sources. If surface Mars rocks have experienced limited wetting conditions as in the Atacama, then Mars coatings may be derived only from dissolution of material adhering to rock.

Dislocation nucleation facilitated by atomic segregation

NASA Astrophysics Data System (ADS)

Zou, Lianfeng; Yang, Chaoming; Lei, Yinkai; Zakharov, Dmitri; Wiezorek, Jörg M. K.; Su, Dong; Yin, Qiyue; Li, Jonathan; Liu, Zhenyu; Stach, Eric A.; Yang, Judith C.; Qi, Liang; Wang, Guofeng; Zhou, Guangwen

2018-01-01

Surface segregation--the enrichment of one element at the surface, relative to the bulk--is ubiquitous to multi-component materials. Using the example of a Cu-Au solid solution, we demonstrate that compositional variations induced by surface segregation are accompanied by misfit strain and the formation of dislocations in the subsurface region via a surface diffusion and trapping process. The resulting chemically ordered surface regions acts as an effective barrier that inhibits subsequent dislocation annihilation at free surfaces. Using dynamic, atomic-scale resolution electron microscopy observations and theory modelling, we show that the dislocations are highly active, and we delineate the specific atomic-scale mechanisms associated with their nucleation, glide, climb, and annihilation at elevated temperatures. These observations provide mechanistic detail of how dislocations nucleate and migrate at heterointerfaces in dissimilar-material systems.

Hummingbird Comet Nucleus Analysis Mission

NASA Technical Reports Server (NTRS)

Kojiro, Daniel; Carle, Glenn C.; Lasher, Larry E.

2000-01-01

Hummingbird is a highly focused scientific mission, proposed to NASA s Discovery Program, designed to address the highest priority questions in cometary science-that of the chemical composition of the cometary nucleus. After rendezvous with the comet, Hummingbird would first methodically image and map the comet, then collect and analyze dust, ice and gases from the cometary atmosphere to enrich characterization of the comet and support landing site selection. Then, like its namesake, Hummingbird would carefully descend to a pre-selected surface site obtaining a high-resolution image, gather a surface material sample, acquire surface temperature and then immediately return to orbit for detailed chemical and elemental analyses followed by a high resolution post-sampling image of the site. Hummingbird s analytical laboratory contains instrumentation for a comprehensive molecular and elemental analysis of the cometary nucleus as well as an innovative surface sample acquisition device.

Automated recycling of chemistry for virtual screening and library design.

PubMed

Vainio, Mikko J; Kogej, Thierry; Raubacher, Florian

2012-07-23

An early stage drug discovery project needs to identify a number of chemically diverse and attractive compounds. These hit compounds are typically found through high-throughput screening campaigns. The diversity of the chemical libraries used in screening is therefore important. In this study, we describe a virtual high-throughput screening system called Virtual Library. The system automatically "recycles" validated synthetic protocols and available starting materials to generate a large number of virtual compound libraries, and allows for fast searches in the generated libraries using a 2D fingerprint based screening method. Virtual Library links the returned virtual hit compounds back to experimental protocols to quickly assess the synthetic accessibility of the hits. The system can be used as an idea generator for library design to enrich the screening collection and to explore the structure-activity landscape around a specific active compound.

Selective enrichment of a methanol-utilizing consortium using pulp & paper mill waste streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregory R. Mockos; William A. Smith; Frank J. Loge

Efficient utilization of carbon inputs is critical to the economic viability of the current forest products sector. Input carbon losses occur in various locations within a pulp mill, including losses as volatile organics and wastewater . Opportunities exist to capture this carbon in the form of value-added products such as biodegradable polymers. Waste activated sludge from a pulp mill wastewater facility was enriched for 80 days for a methanol-utilizing consortium with the goal of using this consortium to produce biopolymers from methanol-rich pulp mill waste streams. Five enrichment conditions were utilized: three high-methanol streams from the kraft mill foul condensatemore » system, one methanol-amended stream from the mill wastewater plant, and one methanol-only enrichment. Enrichment reactors were operated aerobically in sequencing batch mode at neutral pH and 25°C with a hydraulic residence time and a solids retention time of four days. Non-enriched waste activated sludge did not consume methanol or reduce chemical oxygen demand. With enrichment, however, the chemical oxygen demand reduction over 24 hour feed/decant cycles ranged from 79 to 89 %, and methanol concentrations dropped below method detection limits. Neither the non-enriched waste activated sludge nor any of the enrichment cultures accumulated polyhydroxyalkanoates (PHAs) under conditions of nitrogen sufficiency. Similarly, the non-enriched waste activated sludge did not accumulate PHAs under nitrogen limited conditions. By contrast, enriched cultures accumulated PHAs to nearly 14% on a dry weight basis under nitrogen limited conditions. This indicates that selectively-enriched pulp mill waste activated sludge can serve as an inoculum for PHA production from methanol-rich pulp mill effluents.« less

Selective Enrichment of a Methanol-Utilizing Consortium Using Pulp and Paper Mill Waste Streams

NASA Astrophysics Data System (ADS)

Mockos, Gregory R.; Smith, William A.; Loge, Frank J.; Thompson, David N.

Efficient utilization of carbon inputs is critical to the economic viability of the current forest products sector. Input carbon losses occur in various locations within a pulp mill, including losses as volatile organics and wastewater. Opportunities exist to capture this carbon in the form of value-added products such as biodegradable polymers. Wasteactivated sludge from a pulp mill wastewater facility was enriched for 80 days for a methanol-utilizing consortium with the goal of using this consortium to produce biopolymers from methanol-rich pulp mill waste streams. Five enrichment conditions were utilized: three high-methanol streams from the kraft mill foul condensate system, one methanol-amended stream from the mill wastewater plant, and one methanol-only enrichment. Enrichment reactors were operated aerobically in sequencing batch mode at neutral pH and 25°C with a hydraulic residence time and a solids retention time of 4 days. Non-enriched waste activated sludge did not consume methanol or reduce chemical oxygen demand. With enrichment, however, the chemical oxygen demand reduction over 24-h feed/ decant cycles ranged from 79 to 89%, and methanol concentrations dropped below method detection limits. Neither the non-enriched waste-activated sludge nor any of the enrichment cultures accumulated polyhydroxyalkanoates (PHAs) under conditions of nitrogen sufficiency. Similarly, the non-enriched waste activated sludge did not accumulate PHAs under nitrogen-limited conditions. By contrast, enriched cultures accumulated PHAs to nearly 14% on a dry weight basis under nitrogen-limited conditions. This indicates that selectively enriched pulp mill waste activated sludge can serve as an inoculum for PHA production from methanol-rich pulp mill effluents.

Magnetic covalent triazine framework for rapid extraction of phthalate esters in plastic packaging materials followed by gas chromatography-flame ionization detection.

PubMed

Yan, Zijun; He, Man; Chen, Beibei; Gui, Bo; Wang, Cheng; Hu, Bin

2017-11-24

Covalent triazine frameworks (CTFs), featuring with high surface area, good thermal, chemical and mechanical stability, are good adsorbents in sample pretreatment. Herein, magnetic CTFs/Ni composite was prepared by in situ reduction of nickel ions on CTFs matrix with a solvothermal method. The prepared CTFs/Ni composite exhibited good preparation reproducibility, high chemical stability, and high extraction efficiency for targeted phthalate esters (PAEs) due to π-π interaction and hydrophobic effect. The porous structure of CTFs/Ni composite benefited the fast transfer of target PAEs from aqueous solution to the adsorbents, and the integrated magnetism contributed to the rapid separation of adsorbents from sample and elution solution. Based on it, a novel method of magnetic solid phase extraction (MSPE) combined with gas chromatography-flame ionization detector (GC-FID) was developed for the analysis of PAEs including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di-2-ethylhexl phthalate (DEHP), and di-n-octyl phthalate (DNOP) in plastic packaging materials. Under the optimal experimental conditions, the limits of detection (LODs, S/N=3) for six PAEs were found to be in the range of 0.024-0.085mg/kg. The linear range was 0.32-16mg/kg for DMP, DEP, 0.08-80mg/kg for DBP, 0.16-32mg/kg for BBP, DEHP, and 0.32-32mg/kg for DNOP, respectively. The enrichment factors ranged from 59 to 88-fold (theoretical enrichment factor was 133-fold). The proposed method was successfully applied to the analysis of PAEs in various plastic packaging materials with recoveries in the range of 70.6-119% for the spiked samples. This method is characterized with short operation time, high sensitivity, low consumption of harmful organic solvents and can be extended to the analysis of other trace aromatic compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

The fabrication of porous N-doped carbon from widely available urea formaldehyde resin for carbon dioxide adsorption.

PubMed

Liu, Zhen; Du, Zhenyu; Song, Hao; Wang, Chuangye; Subhan, Fazle; Xing, Wei; Yan, Zifeng

2014-02-15

N-doped carbon material constitutes abundant of micropores and basic nitrogen species that have potential implementation for CO2 capture. In this paper, porous carbon material with high nitrogen content was simply fabricated by carbonizing low cost and widely available urea formaldehyde resin, and then followed by KOH activation. CO2 capture experiment showed high adsorption capacity of 3.21 mmol g(-1) at 25 °C under 1 atm for UFCA-2-600. XRD, SEM, XPS and FT-IR analysis confirmed that a graphitic-like structure was retained even after high temperature carbonization and strong base activation. Textural property analysis revealed that narrow micropores, especially below 0.8 nm, were effective for CO2 adsorption by physical adsorption mechanism. Chemical evolved investigation revealed that graphitic-like embedded basic nitrogen groups are generated from bridged and terminal amines of urea formaldehyde resin from thermal carbonization and KOH activation treatment, which is responsible for the enrichment of CO2 capacity by chemical adsorption mechanism. The relationship between CO2 adsorption capacity and pore size or basic N species was also studied, which turned out that both of them played crucial role by physical and chemical adsorption mechanism, respectively. Copyright © 2013 Elsevier Inc. All rights reserved.

Genome-wide Escherichia coli stress response and improved tolerance towards industrially relevant chemicals.

PubMed

Rau, Martin Holm; Calero, Patricia; Lennen, Rebecca M; Long, Katherine S; Nielsen, Alex T

2016-10-13

Economically viable biobased production of bulk chemicals and biofuels typically requires high product titers. During microbial bioconversion this often leads to product toxicity, and tolerance is therefore a critical element in the engineering of production strains. Here, a systems biology approach was employed to understand the chemical stress response of Escherichia coli, including a genome-wide screen for mutants with increased fitness during chemical stress. Twelve chemicals with significant production potential were selected, consisting of organic solvent-like chemicals (butanol, hydroxy-γ-butyrolactone, 1,4-butanediol, furfural), organic acids (acetate, itaconic acid, levulinic acid, succinic acid), amino acids (serine, threonine) and membrane-intercalating chemicals (decanoic acid, geraniol). The transcriptional response towards these chemicals revealed large overlaps of transcription changes within and between chemical groups, with functions such as energy metabolism, stress response, membrane modification, transporters and iron metabolism being affected. Regulon enrichment analysis identified key regulators likely mediating the transcriptional response, including CRP, RpoS, OmpR, ArcA, Fur and GadX. These regulators, the genes within their regulons and the above mentioned cellular functions therefore constitute potential targets for increasing E. coli chemical tolerance. Fitness determination of genome-wide transposon mutants (Tn-seq) subjected to the same chemical stress identified 294 enriched and 336 depleted mutants and experimental validation revealed up to 60 % increase in mutant growth rates. Mutants enriched in several conditions contained, among others, insertions in genes of the Mar-Sox-Rob regulon as well as transcription and translation related gene functions. The combination of the transcriptional response and mutant screening provides general targets that can increase tolerance towards not only single, but multiple chemicals.

76 FR 387 - Atomic Safety and Licensing Board; AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility)

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-04

... and Licensing Board; AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility) December 17, 2010... construction and operation of a gas centrifuge uranium enrichment facility--denoted as the Eagle Rock... site at http://www.nrc.gov/materials/fuel-cycle-fac/arevanc.html . These and other documents relating...

A Summary of Actinide Enrichment Technologies and Capability Gaps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patton, Bradley D.; Robinson, Sharon M.

2017-01-01

The evaluation performed in this study indicates that a new program is needed to efficiently provide a national actinide radioisotope enrichment capability to produce milligram-to-gram quantities of unique materials for user communities. This program should leverage past actinide enrichment, the recent advances in stable isotope enrichment, and assessments of the future requirements to cost effectively develop this capability while establishing an experience base for a new generation of researchers in this vital area. Preliminary evaluations indicate that an electromagnetic isotope separation (EMIS) device would have the capability to meet the future needs of the user community for enriched actinides. Themore » EMIS technology could be potentially coupled with other enrichment technologies, such as irradiation, as pre-enrichment and/or post-enrichment systems to increase the throughput, reduce losses of material, and/or reduce operational costs of the base EMIS system. Past actinide enrichment experience and advances in the EMIS technology applied in stable isotope separations should be leveraged with this new evaluation information to assist in the establishment of a domestic actinide radioisotope enrichment capability.« less

Lessons-Learned from D and D Activities at the Five Gaseous Diffusion Buildings (K-25, K- 27, K-29, K-31 and K-33) East Tennessee Technology Park, Oak Ridge, TN - 13574

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopotic, James D.; Ferri, Mark S.; Buttram, Claude

The East Tennessee Technology Park (ETTP) is the site of five former gaseous diffusion plant (GDP) process buildings that were used to enrich uranium from 1945 to 1985. The process equipment in the original two buildings (K-25 and K-27) was used for the production of highly enriched uranium (HEU), while that in the three later buildings (K-29, K-31 and K-33) produced low enriched uranium (LEU). Equipment was contaminated primarily with uranium and to a lesser extent technetium (Tc). Decommissioning of the GDP process buildings has presented several unique challenges and produced many lessons-learned. Among these is the importance of good,more » up-front characterization in developing the best demolition approach. Also, chemical cleaning of process gas equipment and piping (PGE) prior to shutdown should be considered to minimize the amount of hold-up material that must be removed by demolition crews. Another lesson learned is to maintain shutdown buildings in a dry state to minimize structural degradation which can significantly complicate characterization, deactivation and demolition efforts. Perhaps the most important lesson learned is that decommissioning GDP process buildings is first and foremost a waste logistics challenge. Innovative solutions are required to effectively manage the sheer volume of waste generated from decontamination and demolition (D and D) of these enormous facilities. Finally, close coordination with Security is mandatory to effectively manage Special Nuclear Material (SNM) and classified equipment issues. (authors)« less

Nutrient enrichment reduces constraints on material flows in a detritus-based food web

Treesearch

Wyatt F. Cross; Bruce Wallace; Amy D. Rosemond

2007-01-01

Most aquatic and terrestrial ecosystems are experiencing increased nutrient availability, which is affecting their structure and function. By altering community composition and productivity of consumers, enrichment can indirectly cause changes in the pathways and magnitude of material flows in food webs. These changes, in turn, have major consequences for material...

Enrichment Zoning Options for the Small Nuclear Rocket Engine (SNRE)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruce G. Schnitzler; Stanley K. Borowski

2010-07-01

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. In NASA’s recent Mars Design Reference Architecture (DRA) 5.0 study (NASA-SP-2009-566, July 2009), nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option because of its high thrust and high specific impulse (-900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. An extensive nuclear thermal rocket technology development effortmore » was conducted from 1955-1973 under the Rover/NERVA Program. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art design incorporating lessons learned from the very successful technology development program. Past activities at the NASA Glenn Research Center have included development of highly detailed MCNP Monte Carlo transport models of the SNRE and other small engine designs. Preliminary core configurations typically employ fuel elements with fixed fuel composition and fissile material enrichment. Uniform fuel loadings result in undesirable radial power and temperature profiles in the engines. Engine performance can be improved by some combination of propellant flow control at the fuel element level and by varying the fuel composition. Enrichment zoning at the fuel element level with lower enrichments in the higher power elements at the core center and on the core periphery is particularly effective. Power flattening by enrichment zoning typically results in more uniform propellant exit temperatures and improved engine performance. For the SNRE, element enrichment zoning provided very flat radial power profiles with 551 of the 564 fuel elements within 1% of the average element power. Results for this and alternate enrichment zoning options for the SNRE are compared.« less

Establishment of a Methanogenic Benzene-Degrading Culture and its Implication in Bioremediation

NASA Astrophysics Data System (ADS)

Qiao, W.; Luo, F.; Bawa, N.; Guo, S.; Ye, S.; Edwards, E.

2017-12-01

Benzene is a known human carcinogen and it is a common pollutant in groundwater, mainly resulting from petrochemical industry. Anaerobic degradation of benzene has significant advantages over aerobic processes for in situ bioremediation. In this study, new methanogenic and sulfate-reducing benzene degrading cultures have been enriched. Microbial community composition was characterized with two other previously established benzene-degrading cultures, and their potential use in bioaugmentation is investigated. In this study, a lab microcosm study was conducted anaerobically with contaminated soil and groundwater from a former chemical plant. Benzene degradation was observed in the presence of co-contaminants and electron donor. Through repetitive amendment of benzene, two enrichment cultures have been developed under sulfate and methanogenic conditions. Results from DNA amplicon sequencing and qPCR analysis revealed that an organism similar to previously described benzene-degrading Deltaproteobacterium has been enriched. The microbial community of this culture was compared with other two methanogenic benzene-degrading enrichment cultures that were derived from an oil refinery and a decommissioned gasoline station, and have been maintained for decades. Deltaproteobacterium ORM2-like microbes were dominate in all enrichment cultures, which brought to light benzene-degrading microbes, ORM2 were enriched under different geological conditions distributed around the world. The relative abundance of methanogens was much lower compared to previously established cultures, although substantial amount of methane was produced. The peripheral organisms also vary. To investigate effectiveness of using ORM2-dominant enrichment cultures in bioremediation, microcosm studies were set up using contaminated materials, and a ORM2-dominating methanogenic benzene-degrading culture was used for bioaugmentation. Results revealed that benzene degradation was speeded up under methanogenic or sulfate-reducing condition, and the growth of ORM2 was observed via qPCR analysis. The treatability test is on-going to establish more reliable correspondence between the benzene degraders and natural attenuation potential, to provide more insights into contaminated site management.

Boron filled siloxane polymers for radiation shielding

NASA Astrophysics Data System (ADS)

Labouriau, Andrea; Robison, Tom; Shonrock, Clinton; Simmonds, Steve; Cox, Brad; Pacheco, Adam; Cady, Carl

2018-03-01

The purpose of the present work was to evaluate changes to structure-property relationships of 10B filled siloxane-based polymers when exposed to nuclear reactor radiation. Highly filled polysiloxanes were synthesized with the intent of fabricating materials that could shield high neutron fluences. The newly formulated materials consisted of cross-linked poly-diphenyl-methylsiloxane filled with natural boron and carbon nanofibers. This polymer was chosen because of its good thermal and chemical stabilities, as well as resistance to ionizing radiation thanks to the presence of aromatic groups in the siloxane backbone. Highly isotopically enriched 10B filler was used to provide an efficient neutron radiation shield, and carbon nanofibers were added to improve mechanical strength. This novel polymeric material was exposed in the Annular Core Research Reactor (ACRR) at Sandia National Labs to five different neutron/gamma fluxes consisting of very high neutron fluences within very short time periods. Thermocouples placed on the specimens recorded in-situ temperature changes during radiation exposure, which agreed well with those obtained from our MCNP simulations. Changes in the microstructural, thermal, chemical, and mechanical properties were evaluated by SEM, DSC, TGA, FT-IR NMR, solvent swelling, and uniaxial compressive load measurements. Our results demonstrate that these newly formulated materials are well-suitable to be used in applications that require exposure to different types of ionizing conditions that take place simultaneously.

Boron Filled Siloxane Polymers for Radiation Shielding

DOE PAGES

Labouriau, Andrea; Robison, Tom; Shonrock, Clinton Otto; ...

2017-09-01

The purpose of the present work was to evaluate changes to structure-property relationships of 10B filled siloxane-based polymers when exposed to nuclear reactor radiation. Highly filled polysiloxanes were synthesized with the intent of fabricating materials that could shield high neutron fluences. The newly formulated materials consisted of cross-linked poly-diphenyl-methylsiloxane filled with natural boron and carbon nanofibers. This polymer was chosen because of its good thermal and chemical stabilities, as well as resistance to ionizing radiation thanks to the presence of aromatic groups in the siloxane backbone. Highly isotopically enriched 10B filler was used to provide an efficient neutron radiation shield,more » and carbon nanofibers were added to improve mechanical strength. This novel polymeric material was exposed in the Annular Core Research Reactor (ACRR) at Sandia National Labs to five different neutron/gamma fluxes consisting of very high neutron fluences within very short time periods. Thermocouples placed on the specimens recorded in-situ temperature changes during radiation exposure, which agreed well with those obtained from our MCNP simulations. Changes in the microstructural, thermal, chemical, and mechanical properties were evaluated by SEM, DSC, TGA, FT-IR NMR, solvent swelling, and uniaxial compressive load measurements. In conclusion, our results demonstrate that these newly formulated materials are well-suitable to be used in applications that require exposure to different types of ionizing conditions that take place simultaneously.« less

Boron Filled Siloxane Polymers for Radiation Shielding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Labouriau, Andrea; Robison, Tom; Shonrock, Clinton Otto

The purpose of the present work was to evaluate changes to structure-property relationships of 10B filled siloxane-based polymers when exposed to nuclear reactor radiation. Highly filled polysiloxanes were synthesized with the intent of fabricating materials that could shield high neutron fluences. The newly formulated materials consisted of cross-linked poly-diphenyl-methylsiloxane filled with natural boron and carbon nanofibers. This polymer was chosen because of its good thermal and chemical stabilities, as well as resistance to ionizing radiation thanks to the presence of aromatic groups in the siloxane backbone. Highly isotopically enriched 10B filler was used to provide an efficient neutron radiation shield,more » and carbon nanofibers were added to improve mechanical strength. This novel polymeric material was exposed in the Annular Core Research Reactor (ACRR) at Sandia National Labs to five different neutron/gamma fluxes consisting of very high neutron fluences within very short time periods. Thermocouples placed on the specimens recorded in-situ temperature changes during radiation exposure, which agreed well with those obtained from our MCNP simulations. Changes in the microstructural, thermal, chemical, and mechanical properties were evaluated by SEM, DSC, TGA, FT-IR NMR, solvent swelling, and uniaxial compressive load measurements. In conclusion, our results demonstrate that these newly formulated materials are well-suitable to be used in applications that require exposure to different types of ionizing conditions that take place simultaneously.« less

A new method for recovery of cellulose from lignocellulosic bio-waste: Pile processing.

PubMed

Tezcan, Erdem; Atıcı, Oya Galioğlu

2017-12-01

This paper presents a new delignification method (pile processing) for the recovery of cellulose from lignocellulosic bio-wastes, adapted from heap leaching technology in metallurgy. The method is based on the stacking of cellulosic materials in a pile, irrigation of the pile with aqueous reactive solution from the top, lignin and hemicellulose removal and enrichment of cellulose by the reactive solution while percolation occurs through the bottom of the pile, recirculating the reactive solution after adjusting several values such as chemical concentrations, and allow the system run until the desired time or cellulose purity. Laboratory scale systems were designed using fall leaves (FL) as lignocellulosic waste materials. The ideal condition for FL was noted as: 0.1g solid NaOH addition per gram of FL into the irrigating solution resulting in instant increase in pH to about 13.8, later allowing self-decrease in pH due to delignification over time down to 13.0, at which point another solid NaOH addition was performed. The new method achieved enrichment of cellulose from 30% to 81% and removal of 84% of the lignin that prevents industrial application of lignocellulosic bio-waste using total of 0.3g NaOH and 4ml of water per gram of FL at environmental temperature and pressure. While the stirring reactions used instead of pile processing required the same amount of NaOH, they needed at least 12ml of water and delignification was only 56.1%. Due to its high delignification performance using common and odorless chemicals and simple equipment in mild conditions, the pile processing method has great promise for the industrial evaluation of lignocellulosic bio-waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar-Fiber-Reinforced Polymer-Matrix Composites

DTIC Science & Technology

2012-08-03

is unlimited. Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar ®-Fiber-Reinforced Polymer-Matrix Composites The views, opinions...12211 Research Triangle Park, NC 27709-2211 ballistics, composites, Kevlar , material models, microstructural defects REPORT DOCUMENTATION PAGE 11... Kevlar ®-Fiber-Reinforced Polymer-Matrix Composites Report Title Fiber-reinforced polymer matrix composite materials display quite complex deformation

[Chemical Compositions and Sources Apportionment of Re-suspended Dust in Jincheng].

PubMed

Wang, Yan; Peng, Lin; Li, Li-juan; Zhang, Teng; Liu, Hai-li; Mu, Ling

2016-01-15

In order to make effective plan to provide the scientific basis for prevention and control of re-suspended dust (RD), samples of particulate sources including RD and other pollution sources of Jincheng were collected. Elements, ions and carbon in particulate sources were analyzed. Enrichment factor, potential ecological risk assessment, and chemical mass balance model were used to analyze the chemical composition and the source of RD. The result indicated that the main components in RD of Jingeheng were Si, TC, Ca, OC, Al, Mg, Na, Fe, K and SO4(2-), contributing 61.14% of total mass of RD. The most abundant content of RD was crustal elements, and the ions were enriched in the fine particles. The mass fraction of OC in PM2. was higher, whereas the mass fraction of EC in PM10 was higher, indicating that secondary organic pollutants were mainly dominated in the fine particles. The dust PM2.5 and PM10 potential ecological risk indexes were extremely strong, and PM2.5 had higher ecological harm than PM10. Pb had the highest enrichment factor of 196.97 in PM2.5, which was followed by As, Cr, Ni, V, Zn and Cu, the enrichment factors of which were all greater than 10, indicating that they were apparently enriched and affected by human activities. Soil dust, construction dust, vehicle exhaust, and coal dust were the main sources of RD.

Direct enantio-convergent transformation of racemic substrates without racemization or symmetrization

NASA Astrophysics Data System (ADS)

Ito, Hajime; Kunii, Shun; Sawamura, Masaya

2010-11-01

Asymmetric reactions that transform racemic mixtures into enantio-enriched products are in high demand, but classical kinetic resolution produces enantiopure compounds in <50% yield even in an ideal case. Many deracemization processes have thus been developed including dynamic kinetic resolution and dynamic kinetic asymmetric transformation, which can provide enantio-enriched products even after complete conversion of the racemic starting materials. However, these dynamic processes require racemization or symmetrization of the substrates or intermediates. We demonstrate a direct chemical enantio-convergent transformation without a racemization or symmetrization process. Copper(I)-catalysed asymmetric allylic substitution of a racemic allylic ether afforded a single enantiomer of an α-chiral allylboronate with complete conversion and high enantioselectivity (up to 98% enantiomeric excess). One enantiomer of the substrate undergoes an anti-SN2'-type reaction whereas the other enantiomer reacts via a syn-SN2' pathway. The products, which cannot be prepared by dynamic procedures, have been used to construct all-carbon quaternary stereocentres.

Deuterium enrichment of polycyclic aromatic hydrocarbons by photochemically induced exchange with deuterium-rich cosmic ices

NASA Technical Reports Server (NTRS)

Sandford, S. A.; Bernstein, M. P.; Allamandola, L. J.; Gillette, J. S.; Zare, R. N.

2000-01-01

The polycyclic aromatic hydrocarbon (PAH) coronene (C24H12) frozen in D2O ice in a ratio of less than 1 part in 500 rapidly exchanges its hydrogen atoms with the deuterium in the ice at interstellar temperatures and pressures when exposed to ultraviolet radiation. Exchange occurs via three different chemical processes: D atom addition, D atom exchange at oxidized edge sites, and D atom exchange at aromatic edge sites. Observed exchange rates for coronene (C24H12)-D2O and d12-coronene (C24D12)-H2O isotopic substitution experiments show that PAHs in interstellar ices could easily attain the D/H levels observed in meteorites. These results may have important consequences for the abundance of deuterium observed in aromatic materials in the interstellar medium and in meteorites. These exchange mechanisms produce deuteration in characteristic molecular locations on the PAHs that may distinguish them from previously postulated processes for D enrichment of PAHs.

Modification of REE distribution of ordinary chondrites from Atacama (Chile) and Lut (Iran) hot deserts: Insights into the chemical weathering of meteorites

NASA Astrophysics Data System (ADS)

Pourkhorsandi, Hamed; D'Orazio, Massimo; Rochette, Pierre; Valenzuela, Millarca; Gattacceca, Jérôme; Mirnejad, Hassan; Sutter, Brad; Hutzler, Aurore; Aboulahris, Maria

2017-09-01

The behavior of rare earth elements (REEs) during hot desert weathering of meteorites is investigated. Ordinary chondrites (OCs) from Atacama (Chile) and Lut (Iran) deserts show different variations in REE composition during this process. Inductively coupled plasma-mass spectrometry (ICP-MS) data reveal that hot desert OCs tend to show elevated light REE concentrations, relative to OC falls. Chondrites from Atacama are by far the most enriched in REEs and this enrichment is not necessarily related to their degree of weathering. Positive Ce anomaly of fresh chondrites from Atacama and the successive formation of a negative Ce anomaly with the addition of trivalent REEs are similar to the process reported from Antarctic eucrites. In addition to REEs, Sr and Ba also show different concentrations when comparing OCs from different hot deserts. The stability of Atacama surfaces and the associated old terrestrial ages of meteorites from this region give the samples the necessary time to interact with the terrestrial environment and to be chemically modified. Higher REE contents and LREE-enriched composition are evidence of contamination by terrestrial soil. Despite their low degrees of weathering, special care must be taken into account while working on the REE composition of Atacama meteorites for cosmochemistry applications. In contrast, chondrites from the Lut desert show lower degrees of REE modification, despite significant weathering signed by Sr content. This is explained by the relatively rapid weathering rate of the meteorites occurring in the Lut desert, which hampers the penetration of terrestrial material by forming voluminous Fe oxide/oxyhydroxides shortly after the meteorite fall.

Abundance, distribution and bioavailability of major and trace elements in surface sediments from the Cai River estuary and Nha Trang Bay (South China Sea, Vietnam)

NASA Astrophysics Data System (ADS)

Koukina, S. E.; Lobus, N. V.; Peresypkin, V. I.; Dara, O. M.; Smurov, A. V.

2017-11-01

Major (Si, Al, Fe, Ti, Mg, Ca, Na, K, S, P), minor (Mn) and trace (Li, V, Cr, Co, Ni, Cu, Zn, As, Sr, Zr, Mo, Cd, Ag, Sn, Sb, Cs, Ba, Hg, Pb, Bi and U) elements, their chemical forms and the mineral composition, organic matter (TOC) and carbonates (TIC) in surface sediments from the Cai River estuary and Nha Trang Bay were first determined along the salinity gradient. The abundance and ratio of major and trace elements in surface sediments are discussed in relation to the mineralogy, grain size, depositional conditions, reference background and SQG values. Most trace-element contents are at natural levels and are derived from the composition of rocks and soils in the watershed. A severe enrichment of Ag is most likely derived from metal-rich detrital heavy minerals such as Ag-sulfosalts. Along the salinity gradient, several zones of metal enrichment occur in surface sediments because of the geochemical fractionation of the riverine material. The parts of actually and potentially bioavailable forms (isolated by four single chemical reagent extractions) are most elevated for Mn and Pb (up to 36% and 32% of total content, respectively). The possible anthropogenic input of Pb in the region requires further study. Overall, the most bioavailable parts of trace elements are associated with easily soluble amorphous Fe and Mn oxyhydroxides. The sediments are primarily enriched with bioavailable metal forms in the riverine part of the estuary. Natural (such as turbidities) and human-generated (such as urban and industrial activities) pressures are shown to influence the abundance and speciation of potential contaminants and therefore change their bioavailability in this estuarine system.

Chemical and oxygen isotopic properties of ordinary chondrites (H5, L6) from Oman: Signs of isotopic equilibrium during thermal metamorphism

NASA Astrophysics Data System (ADS)

Ali, Arshad; Nasir, Sobhi J.; Jabeen, Iffat; Al Rawas, Ahmed; Banerjee, Neil R.; Osinski, Gordon R.

2017-10-01

Mean bulk chemical data of recently found H5 and L6 ordinary chondrites from the deserts of Oman generally reflect isochemical features which are consistent with the progressive thermal metamorphism of a common, unequilibrated starting material. Relative differences in abundances range from 0.5-10% in REE (Eu = 14%), 6-13% in siderophile elements (Co = 48%), and >10% in lithophile elements (exceptions are Ba, Sr, Zr, Hf, U = >30%) between H5 and L6 groups. These differences may have accounted for variable temperature conditions during metamorphism on their parent bodies. The CI/Mg-normalized mean abundances of refractory lithophile elements (Al, Ca, Sm, Yb, Lu, V) show no resolvable differences between H5 and L6 suggesting that both groups have experienced the same fractionation. The REE diagram shows subtle enrichment in LREE with a flat HREE pattern. Furthermore, overall mean REE abundances are 0.6 × CI with enriched La abundance ( 0.9 × CI) in both groups. Precise oxygen isotope compositions demonstrate the attainment of isotopic equilibrium by progressive thermal metamorphism following a mass-dependent isotope fractionation trend. Both groups show a slope-1/2 line on a three-isotope plot with subtle negative deviation in Δ17O associated with δ18O enrichment relative to δ17O. These deviations are interpreted as the result of liberation of water from phyllosilicates and evaporation of a fraction of the water during thermal metamorphism. The resultant isotope fractionations caused by the water loss are analogous to those occurring between silicate melt and gas phase during CAI and chondrule formation in chondrites and are controlled by cooling rates and exchange efficiency.

A single low-energy, iron-poor supernova as the source of metals in the star SMSS J031300.36-670839.3.

PubMed

Keller, S C; Bessell, M S; Frebel, A; Casey, A R; Asplund, M; Jacobson, H R; Lind, K; Norris, J E; Yong, D; Heger, A; Magic, Z; Da Costa, G S; Schmidt, B P; Tisserand, P

2014-02-27

The element abundance ratios of four low-mass stars with extremely low metallicities (abundances of elements heavier than helium) indicate that the gas out of which the stars formed was enriched in each case by at most a few--and potentially only one--low-energy supernova. Such supernovae yield large quantities of light elements such as carbon but very little iron. The dominance of low-energy supernovae seems surprising, because it had been expected that the first stars were extremely massive, and that they disintegrated in pair-instability explosions that would rapidly enrich galaxies in iron. What has remained unclear is the yield of iron from the first supernovae, because hitherto no star has been unambiguously interpreted as encapsulating the yield of a single supernova. Here we report the optical spectrum of SMSS J031300.36-670839.3, which shows no evidence of iron (with an upper limit of 10(-7.1) times solar abundance). Based on a comparison of its abundance pattern with those of models, we conclude that the star was seeded with material from a single supernova with an original mass about 60 times that of the Sun (and that the supernova left behind a black hole). Taken together with the four previously mentioned low-metallicity stars, we conclude that low-energy supernovae were common in the early Universe, and that such supernovae yielded light-element enrichment with insignificant iron. Reduced stellar feedback both chemically and mechanically from low-energy supernovae would have enabled first-generation stars to form over an extended period. We speculate that such stars may perhaps have had an important role in the epoch of cosmic reionization and the chemical evolution of early galaxies.

Constitutive mass balance relations between chemical composition, volume, density, porosity, and strain in metasomatic hydrochemical systems: Results on weathering and pedogenesis

NASA Astrophysics Data System (ADS)

Brimhall, George H.; Dietrich, William E.

1987-03-01

Relations characterizing the chemical, physical, and mechanical changes resulting from metasomatic hydrochemical processes are developed using mass balance models which formally link chemical composition to bulk density, mineral density, volumetric properties, porosity, and amount of deformation (strain). Rigorous analysis of aqueous solute transport effects is then made possible in a variety of porous media flow environments including chemical weathering, pedogenesis (soil formation), diagenesis, ore deposition and enrichment, and metamorphism. Application of these linear constitutive relations to chemical weathering profiles shows that immobile and locally mobile chemical elements, with masses conserved on the scale of soil profiles, can be accurately identified from analysis of appropriate data arrays and then used as natural geochemical tracers to infer the nature and extent of hydrochemical weathering processes and volume changes during pedogenesis. Assumptions commonly made in the past about the supposed immobility of certain elements, e.g., Ti and Zr, become unnecessary. Quantitative differentiation between the effects of residual and supergene fractionation is then easily made. These methods are applied to Ni-rich laterites developed by weathering of ultramafic rocks, showing that during ordinary residual enrichment, Ni is concentrated by as much as 4× protolith peridotite concentrations. This occurs simply by silicate mineral dissolution and removal of chemical elements other than Ni ( e.g., Mg) with a corresponding reduction in saprolite density and increase in bulk porosity without significant deformation. In contrast, laterites with mineable concentrations of Ni which are similarly undeformed (such as the Nickel Mountain Mine in Riddle, Oregon) have experienced, in addition to residual enrichment, strong supergene enrichment by fractionation of ore elements between a leached zone from which Ni is extracted and a complementary enriched zone positioned farther along the direction of ground water flow. Soil-forming processes in podzol chronosequences developed on sandy beach terraces of the Mendocino Coast of California involved soil column collapse of 60 percent by dissolution of silicate minerals in the albic horizon of Al and Fe leaching, and 70 percent dilation (expansion) in the overlying organic-rich layer by root growth. The amount of erosion based upon paleosurface reconstructions using the excess mass of Fe, Al, Pb, Ga, and Cu in the zone of supergene enrichment (spodic horizon) below the ground water table indicates that subsurface erosion by dissolutional collapse is three times that of surficial erosion. Finally, using published chemical data for Ti, Zr, and Cr on major bauxite deposits in Australia where erosion rates are thought to be low, we infer that there may have been major amounts of dissolutional collapse to explain the upwards increase of detrital zircon and rutile in weathering profiles.

Kelvin-Helmholtz instabilities as the source of inhomogeneous mixing in nova explosions.

PubMed

Casanova, Jordi; José, Jordi; García-Berro, Enrique; Shore, Steven N; Calder, Alan C

2011-10-19

Classical novae are thermonuclear explosions in binary stellar systems containing a white dwarf accreting material from a close companion star. They repeatedly eject 10(-4)-10(-5) solar masses of nucleosynthetically enriched gas into the interstellar medium, recurring on intervals of decades to tens of millennia. They are probably the main sources of Galactic (15)N, (17)O and (13)C. The origin of the large enhancements and inhomogeneous distribution of these species observed in high-resolution spectra of ejected nova shells has, however, remained unexplained for almost half a century. Several mechanisms, including mixing by diffusion, shear or resonant gravity waves, have been proposed in the framework of one-dimensional or two-dimensional simulations, but none has hitherto proven successful because convective mixing can only be modelled accurately in three dimensions. Here we report the results of a three-dimensional nuclear-hydrodynamic simulation of mixing at the core-envelope interface during nova outbursts. We show that buoyant fingering drives vortices from the Kelvin-Helmholtz instability, which inevitably enriches the accreted envelope with material from the outer white-dwarf core. Such mixing also naturally produces large-scale chemical inhomogeneities. Both the metallicity enhancement and the intrinsic dispersions in the abundances are consistent with the observed values.

Preparation of dietary fibre-enriched materials from preharvest dropped apples and their utilisation as a high-fibre flour substitute.

PubMed

Kim, Yujeong; Kim, Yongwook; Bae, In Young; Lee, Hyeon Gyu; Lee, Suyong

2013-06-01

Preharvest dropped apples from a weather disaster are generally discarded or used in animal feed due to reduced market value. In this study, they were utilised to produce dietary fibre-enriched materials (DFEMs) and their baking performance in a food system was then evaluated as a high-fibre and low-calorie flour substitute. Hydrothermal treatment and fractionation of preharvest dropped apple powder produced fibre-rich fractions (856.2 g kg(-1)). The use of DFEMs increased the pasting properties of wheat flour and improved dough mixing stability. When DFEMs were incorporated in the cookie formulation (2, 4 and 6 g dietary fibre per serving), the cookie dough exhibited increased elongational viscosity and solid-like behaviour which became more pronounced with increasing levels of DEFMs. After baking, reduced spread was observed in DFEM cookies which could be readily attributed to their rheological characteristics. However, greater moisture retention by DFEMs produced cookie samples with softer texture. DFEMs prepared from preharvest dropped apples could be successfully evaluated in a cookie model system as a high-fibre and low-calorie substitute for wheat flour. This study suggests a new value-added application of preharvest dropped fruits, positively extending their use for better healthful diets. © 2012 Society of Chemical Industry.

Stretching and smearing of chemical heterogeneity by melting and melt migration beneath mid-ocean ridges

NASA Astrophysics Data System (ADS)

Liu, B.; Liang, Y.

2017-12-01

The size of mantle source heterogeneity is important to the interpretation of isotopic signals observed in residual peridotites and basalts. During concurrent melting and melt migration beneath a mid-ocean ridge, both porosity and melt velocity increase upward, resulting in an upward increase in the effective transport velocity for a trace element. Hence a chemical heterogeneity of finite size will be stretched during its transport in the upwelling mantle. This melt migration induced chemical deformation can be quantified by a simple stretching factor. During equilibrium melting, the isotope signals of Sr, Nd and Hf in a 1 km size enriched mantle will be stretched to 2 6 km at the top of the melting column, depending on the style of melt migration. A finite rate of diffusive exchange between residual minerals and partial melt will result in smearing of chemical heterogeneity during its transport in the upwelling melting column. A Gaussian-shaped enriched source in depleted background mantle would be gradually deformed its transit through the melting column. The width of the enriched signal spreads out between the fronts of melt and solid while its amplitude decreases. This melt migration induced smearing also cause mixing of nearby heterogeneities or absorption of enriched heterogeneity by the ambient mantle. Smaller heterogeneities in the solid is more efficiently mixed or aborted by the background mantle than larger ones. Mixing of heterogeneities in the melt depends on the size in the same sense although the erupted melt is more homogenized due to melt accumulation and magma chamber process. The mapping of chemical heterogeneities observed in residual peridotites and basalts into their source region is therefore highly nonlinear. We will show that the observed variations in Nd and Hf isotopes in the global MORB and abyssal peridotites are consistent with kilometer-scale enriched heterogeneities embedded in depleted MORB mantle.

Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar (registered trademark)-Fiber-Reinforced Polymer-Matrix Composites

DTIC Science & Technology

2013-03-01

of coarser-scale materials and structures containing Kevlar fibers (e.g., yarns, fabrics, plies, lamina, and laminates ). Journal of Materials...Multi-Length Scale-Enriched Continuum-Level Material Model for Kevlar -Fiber-Reinforced Polymer-Matrix Composites M. Grujicic, B. Pandurangan, J.S...extensive set of molecular-level computational analyses regarding the role of various microstructural/morphological defects on the Kevlar fiber

On volatile element trends in gas-rich meteorites

NASA Technical Reports Server (NTRS)

Bart, G.; Lipschutz, M. E.

1979-01-01

Ten volatile elements (and non-volatile Co) in co-existing light and dark portions of 5 gas-rich chondrites were studied. Patterns of distinct but non-uniform enrichment by dark admixing material are revealed. The dark admixing material is enriched in Cs; Bi and Tl covary in it. It is compositionally unique from known types of primitive materials and is apparently not derived by secondary processes from such materials.

Chemical fractionation resulting from the hypervelocity impact process on metallic targets

NASA Astrophysics Data System (ADS)

Libourel, Guy; Ganino, Clément; Michel, Patrick; Nakamura, Akiko

2016-10-01

In a regime of hypervelocity impact cratering, the internal energy deposited in target + projectile region is large enough to melt and/or vaporize part of the material involved, which expands rapidly away from the impact site. Fast and energetic impact processes have therefore important chemical consequences on the projectile and target rock transformations during major impact events. Several physical and chemical processes occurred indeed in the short duration of the impact, e.g., melting, coating, mixing, condensation, crystallization, redox reactions, quenching, etc., all concurring to alter both projectile and target composition on the irreversible way.In order to document such hypervelocity impact chemical fractionation, we have started a program of impact experiments by shooting doped (27 trace elements) millimeter-sized basalt projectiles on metallic target using a two stages light gas gun. With impact velocity in the range from 0.25 to 7 km.s-1, these experiments are aimed i) to characterize chemically and texturally all the post-mortem materials (e.g., target, crater, impact melt, condensates, and ejectas), in order ii) to make a chemical mass balance budget of the process, and iii) to relate it to the kinetic energy involved in the hypervelocity impacts for scaling law purpose. Irrespective of the incident velocities, our preliminary results show the importance of redox processes, the significant changes in the ejecta composition (e.g., iron enrichment) and the systematic coating of the crater by the impact melt [1]. On the target side, characterizations of the microstructure of the shocked iron alloys to better constrain the shielding processes. We also show how these results have great implications in our understanding on the current surface properties of small bodies, and chiefly in the case of M-type asteroids. [1] Ganino C, Libourel G, Nakamura AM & Michel P (2015) Goldschmidt Abstracts, 2015 990.

20180311 - Use of ToxPrint chemotypes for exploring chemical feature enrichments across the ToxCast chemical-assay landscape (SOT)

EPA Science Inventory

EPA’s ToxCast chemical library spans diverse chemical use-types, functionalities, structures and features potentially relevant to toxicity and environmental exposure. However, this structural diversity, along with assay noise and low average hit rates across the varied Tox...

Use of ToxPrint chemotypes for exploring chemical feature enrichments across the ToxCast chemical-assay landscape

EPA Science Inventory

EPA’s ToxCast chemical library spans diverse chemical use-types, functionalities, structures and features potentially relevant to toxicity and environmental exposure. However, this structural diversity, along with assay noise and low average hit rates across the varied ToxCast h...

Effects of Enrichment and Litter Parity on Reproductive Performance and Behavior in BALB/c and 129/Sv Mice.

PubMed

Whitaker, Julia W; Moy, Sheryl S; Pritchett-Corning, Kathleen R; Fletcher, Craig A

2016-01-01

We examined the effect of adding species-appropriate environmental enrichment items to breeding cages of BALB/cAnNCrl and 129S2/SvPasCrl mice. The 3 enrichment conditions were: 1) cotton nesting material; 2) nesting material plus a paper shelter and rolled paper bedding; and 3) an igloo dome with an exercise wheel in addition to the shelter-group enrichments. We measured litter size, litter survival to weaning age, average pup weight at 21 d, and the interlitter interval to evaluate reproductive performance. A random subset of the first- or second-litter offspring from each enrichment condition and strain was assessed in multiple behavioral tests. Enrichment significantly affected anxiety-like behavior and sociability, with the direction of change dependent on strain and sex. Litter parity had greater effects on some reproductive parameters than did the enrichment condition, and this effect was not solely due to a difference between the first compared with subsequent litters. The significant effects of litter parity on the number of pups born and weaned, female pup weight, and interlitter interval were dependent on the enrichment condition in BALB/c but not 129/Sv mice. Offspring from the first or second litter were included in a generational component to investigate whether enrichment effects on reproduction persist in adult offspring after transfer to a different facility for breeding. Natal cage enrichment had no effect on any reproductive parameter in the transferred mice. Overall, additional enrichment beyond nesting material had a beneficial effect on the interlitter interval in BALB/c mice and on the number of pups weaned in 129/Sv mice.

Effects of Enrichment and Litter Parity on Reproductive Performance and Behavior in BALB/c and 129/Sv Mice

PubMed Central

Whitaker, Julia W; Moy, Sheryl S; Pritchett-Corning, Kathleen R; Fletcher, Craig A

2016-01-01

We examined the effect of adding species-appropriate environmental enrichment items to breeding cages of BALB/cAnNCrl and 129S2/SvPasCrl mice. The 3 enrichment conditions were: 1) cotton nesting material; 2) nesting material plus a paper shelter and rolled paper bedding; and 3) an igloo dome with an exercise wheel in addition to the shelter-group enrichments. We measured litter size, litter survival to weaning age, average pup weight at 21 d, and the interlitter interval to evaluate reproductive performance. A random subset of the first- or second-litter offspring from each enrichment condition and strain was assessed in multiple behavioral tests. Enrichment significantly affected anxiety-like behavior and sociability, with the direction of change dependent on strain and sex. Litter parity had greater effects on some reproductive parameters than did the enrichment condition, and this effect was not solely due to a difference between the first compared with subsequent litters. The significant effects of litter parity on the number of pups born and weaned, female pup weight, and interlitter interval were dependent on the enrichment condition in BALB/c but not 129/Sv mice. Offspring from the first or second litter were included in a generational component to investigate whether enrichment effects on reproduction persist in adult offspring after transfer to a different facility for breeding. Natal cage enrichment had no effect on any reproductive parameter in the transferred mice. Overall, additional enrichment beyond nesting material had a beneficial effect on the interlitter interval in BALB/c mice and on the number of pups weaned in 129/Sv mice. PMID:27423144

Distinct Litter Stabilization Dynamics Pathways for Decomposition of Pine Needle and Fine Root Within Soil

NASA Astrophysics Data System (ADS)

Mambelli, S.; Filley, T. R.; Bird, J.; Dawson, T.; Torn, M. S.

2008-12-01

The chemical composition of litter imparts a strong control on the initial rates of microbial decay but it is unclear how plant chemistry influences the ultimate stabilization of soil organic matter (SOM) and the nature of the products stabilized. We determined the concentration and 13C enrichment of lignin phenols and substituted fatty acids (SFA) in SOM fractions from an experiment in which 13C- and 15N-labeled needles or fine roots were added to the mineral soil in a Ponderosa pine (Pinus ponderosa) forest in the Sierra Nevada, CA, USA. 1.5 y after litter addition, we analyzed bulk soil (< 2 mm), free light fraction (LF, mean residence time (MRT) ~5 y) and alkali/acid insoluble humin (MRT ~270 y) fractions. Needles contained nearly 2 and 3x the lignin and SFA content per organic carbon unit as did roots. Lignin and SFA decreased from the free LF to the bulk soil to the humin fraction; and molecular properties were more similar within a SOM fraction regardless of the litter source. However, LF and humin from the root addition contained more lignin than from the needle addition. Based upon the relative movement of litter-derived 13C and 15N into SOM fractions during 1.5 y, it was proposed that the 13C accumulation in the humin fraction for needles was derived from high C/N, needle-derived biopolymer molecular fragments that are surficially associated with particles. In contrast, the root-derived material entering SOM fractions was much lower in C/N and was likely from microbial by-products. Consistent with this hypothesis, both lignin and SFA in the LF and humin fractions amended with enriched needles were highly enriched (+ 30-60 permil) with respect to the SOM fractions from soils amended with roots. These differences were large even considering the lower concentration of SFA and lignin in root material. Although the chemistry and MRT of LF and humin were dramatically different, the extent of 13C-enrichment among lignin and SFA were comparable for the needle experiment while most lignin phenols for the humin from the root addition had greater 13C content than SFA. This indicates that molecular fragments of plant biopolymers can readily associate with both labile and stabilized SOM fractions. At the same time, these results suggest that distinct decomposition and stabilization pathways exist for litters, such as needles vs. roots, of different chemical quality.

Quantitative chemical biosensing by bacterial chemotaxis in microfluidic chips.

PubMed

Roggo, Clémence; Picioreanu, Cristian; Richard, Xavier; Mazza, Christian; van Lintel, Harald; van der Meer, Jan Roelof

2018-01-01

Whole-cell bacterial bioreporters are proposed as alternatives to chemical analysis of, for example, pollutants in environmental compartments. Commonly based on reporter gene induction, bioreporters produce a detectable signal within 30 min to a few hours after exposure to the chemical target, which is impractical for applications aiming at a fast response. In an attempt to attain faster readout but maintain flexibility of chemical targeting, we explored the concept for quantitative chemical sensing by bacterial chemotaxis. Chemotaxis was quantified from enrichment of cells across a 600 µm-wide chemical gradient stabilized by parallel flow in a microfluidic chip, further supported by transport and chemotaxis steady state and kinetic modelling. As proof-of-concept, we quantified Escherichia coli chemotaxis towards serine, aspartate and methylaspartate as a function of attractant concentration and exposure time. E. coli chemotaxis enrichment increased sharply between 0 and 10 µM serine, before saturating at 100 µM. The chemotaxis accumulation rate was maximal at 10 µM serine, leading to observable cell enrichment within 5 min. The potential application for biosensing of environmental toxicants was investigated by quantifying chemotaxis of Cupriavidus pinatubonensis JMP134 towards the herbicide 2,4-dichlorophenoxyacetate. Our results show that bacterial chemotaxis can be quantified on a scale of minutes and may be used for developing faster bioreporter assays. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

10 CFR 70.23a - Hearing required for uranium enrichment facility.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Hearing required for uranium enrichment facility. 70.23a... MATERIAL License Applications § 70.23a Hearing required for uranium enrichment facility. The Commission... license for construction and operation of a uranium enrichment facility. The Commission will publish...

10 CFR 70.23a - Hearing required for uranium enrichment facility.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false Hearing required for uranium enrichment facility. 70.23a... MATERIAL License Applications § 70.23a Hearing required for uranium enrichment facility. The Commission... license for construction and operation of a uranium enrichment facility. The Commission will publish...

10 CFR 70.23a - Hearing required for uranium enrichment facility.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false Hearing required for uranium enrichment facility. 70.23a... MATERIAL License Applications § 70.23a Hearing required for uranium enrichment facility. The Commission... license for construction and operation of a uranium enrichment facility. The Commission will publish...

10 CFR 70.23a - Hearing required for uranium enrichment facility.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false Hearing required for uranium enrichment facility. 70.23a... MATERIAL License Applications § 70.23a Hearing required for uranium enrichment facility. The Commission... license for construction and operation of a uranium enrichment facility. The Commission will publish...

10 CFR 70.23a - Hearing required for uranium enrichment facility.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Hearing required for uranium enrichment facility. 70.23a... MATERIAL License Applications § 70.23a Hearing required for uranium enrichment facility. The Commission... license for construction and operation of a uranium enrichment facility. The Commission will publish...

76 FR 67765 - Notice of Availability of Uranium Enrichment Fuel Cycle Facility's Inspection Reports Regarding...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-02

... Uranium Enrichment Fuel Cycle Facility's Inspection Reports Regarding Louisiana Energy Services, National..., Uranium Enrichment Branch, Division of Fuel Cycle Safety and Safeguards, Office of Nuclear Material Safety... Commission. Brian W. Smith, Chief, Uranium Enrichment Branch, Division of Fuel Cycle Safety and Safeguards...

75 FR 62895 - Notice of Availability of Safety Evaluation Report; AREVA Enrichment Services LLC, Eagle Rock...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-13

... Evaluation Report; AREVA Enrichment Services LLC, Eagle Rock Enrichment Facility, Bonneville County, ID... report. FOR FURTHER INFORMATION CONTACT: Breeda Reilly, Senior Project Manager, Advanced Fuel Cycle, Enrichment, and Uranium Conversion, Division of Fuel Cycle Safety and Safeguards, Office of Nuclear Material...

Quantitative atomic-scale structure characterization of ordered mesoporous carbon materials by solid state NMR

DOE PAGES

Wang, Zhuoran; Opembe, Naftali; Kobayashi, Takeshi; ...

2018-02-03

In this study, solid-state (SS)NMR techniques were applied to characterize the atomic-scale structures of ordered mesoporous carbon (OMC) materials prepared using Pluronic F127 as template with resorcinol and formaldehyde as polymerizing precursors. A rigorous quantitative analysis was developed using a combination of 13C SSNMR spectra acquired with direct polarization and cross polarization on natural abundant and selectively 13C-enriched series of samples pyrolyzed at various temperatures. These experiments identified and counted the key functional groups present in the OMCs at various stages of preparation and thermal treatment. Lastly, the chemical evolution of molecular networks, the average sizes of aromatic clusters andmore » the extended molecular structures of OMCs were then inferred by coupling this information with the elemental analysis results.« less

Quantitative atomic-scale structure characterization of ordered mesoporous carbon materials by solid state NMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhuoran; Opembe, Naftali; Kobayashi, Takeshi

In this study, solid-state (SS)NMR techniques were applied to characterize the atomic-scale structures of ordered mesoporous carbon (OMC) materials prepared using Pluronic F127 as template with resorcinol and formaldehyde as polymerizing precursors. A rigorous quantitative analysis was developed using a combination of 13C SSNMR spectra acquired with direct polarization and cross polarization on natural abundant and selectively 13C-enriched series of samples pyrolyzed at various temperatures. These experiments identified and counted the key functional groups present in the OMCs at various stages of preparation and thermal treatment. Lastly, the chemical evolution of molecular networks, the average sizes of aromatic clusters andmore » the extended molecular structures of OMCs were then inferred by coupling this information with the elemental analysis results.« less

The sources and composition of humus in some soils of West Antarctica

NASA Astrophysics Data System (ADS)

Abakumov, E. V.

2010-05-01

Original data on humus-forming substances and their elemental and biochemical compositions in Antarctic soils are discussed. Mosses, lichens, algae, remains of higher vascular plants, and penguin guano of two types differ considerably in their chemical compositions. This leads to significant differences in the formation of humic substances in plant materials themselves in the course of their transformation. However, no significant differences in the composition of humus in the fine earth of soils developing under different humus-forming materials have been revealed, which may be related to the extremely low rates of humification. Significant differences between the soils of Antarctic landscapes proper and the soils of the Subantarctic King George Island are only observed in the humus enrichment with nitrogen. The soils of Antarctica are low-humus soils with the humate-fulvate or fulvate types of humus.

Origin of peralkaline granites of Saudi Arabia

NASA Astrophysics Data System (ADS)

Radain, A. A. M.; Fyfe, W. S.; Kerrich, R.

1982-01-01

Small volumes of peralkaline granites were generated as the final phase of a Pan African calc-alkaline igneous event which built the Arabian Peninsula. The peralkaline granites are closely associated with trends or sutures related to ophiolites. Peralkaline rocks are chemically heterogeneous, with anomalous abundances of Zr (average 2,150 ppm±2,600 1σ), Y (200±190), and Nb (105±100), representing up to ten-fold enrichments of these elements relative to abundances in calc alkaline granite counterparts. Large enrichments of some rare earth elements and fluorine are also present. The peralkaline granites have scattered whole rock 18O values, averaging 8.7±0.6% in the Hadb Aldyaheen Complex and 10.7±1% in the Jabal Sayid Complex. Quartz-albite fractionations of 0.5 to 1.5% signify that the heavier whole rock δ-values probably represent the oxygen isotope composition of the peralkaline magma. Small variable enrichments of 18O, in conjunction with slightly elevated 87Sr/86Sr initial ratios relative to broadly contemporaneous calc alkaline granites, are both suggestive of a small degree of involvement of crustal, or crustal derived material in the peralkaline magmas. It is proposed that the peculiar magma genesis is associated with a relaxation event which followed continental collision and underthrusting of salt rich sediments.

Combined Li-He isotopes in Iceland and Jan Mayen basalts and constraints on the nature of the North Atlantic mantle

NASA Astrophysics Data System (ADS)

Magna, T.; Wiechert, U.; Stuart, F. M.; Halliday, A. N.; Harrison, D.

2011-02-01

Lithium (Li) isotopes are thought to provide a powerful proxy for the recycling of crustal material, affected by low temperature alteration, through the mantle. We present Li isotope compositions for basaltic volcanic rocks from Hengill, Iceland, and Jan Mayen in order to examine possible links between ocean island volcanism and recycled oceanic crust and to address recent suggestions that mantle 3He/ 4He is also related to recycling of ancient slabs. Basaltic glasses spanning a range of chemical enrichment from the Hengill fissure system define an inverse correlation between δ 7Li (3.8-6.9‰) and 3He/ 4He (12-20 RA). The high- 3He/ 4He basalts have low δ 18O as well as excess Eu and high Nb/U, but carry no Li isotope evidence of being the product of recycling of altered slab or wedge material. In fact, there is no clear correlation between Li or He isotopes on the one hand and any of the other fingerprints of recycled slab components. The low- 3He/ 4He samples do have elevated Nb/U, Sr/Nd, positive Eu anomalies and high δ 7Li (˜6.9‰), providing evidence of a cumulate-enriched source that could be part of an ancient altered ocean floor slab. Basalts from Jan Mayen are characterized by large degrees of enrichment in incompatible trace elements typical of EM-like basalts but have homogeneous δ 7Li typical of depleted mantle (3.9-4.7‰) providing evidence for a third mantle source in the North Atlantic. It appears that oceanic basalts can display a wide range in isotope and trace element compositions associated with recycled components whilst exhibiting no sign of modern surface-altered slab or wedge material from the Li isotope composition.

Techniques for Measurement of Nitrate Movement in Soils

NASA Technical Reports Server (NTRS)

Broadbent, F. E.

1971-01-01

Contamination of surface and ground waters with nitrate usually involves leaching through soil of nitrate produced by mineralization of soil organic matter, decomposition of animal wastes or plant residues, or derived from fertilizers. Nitrate concentrations in the soil solution may be measured by several chemical procedures or by the nitrate electrode. since nitrate is produced throughout the soil mass it is difficult to identify a source of nitrate contamination by conventional means. This problem can be solved by use of N-15-enriched or N-15-depleted materials as tracers. The latter is particularly attractive because of the negligible possibility of the tracer hazardous to health.

Grainsize evolution and differential comminution in an experimental regolith

NASA Technical Reports Server (NTRS)

Horz, F.; Cintala, M.; See, T.

1984-01-01

The comminution of planetary surfaces by exposure to continuous meteorite bombardment was simulated by impacting the same fragmental gabbro target 200 times. The role of comminution and in situ gardening of planetary regoliths was addressed. Mean grain size continuously decreased with increasing shot number. Initially it decreased linearly with accumulated energy, but at some stage comminution efficiency started to decrease gradually. Point counting techniques, aided by the electron microprobe for mineral identification, were performed on a number of comminution products. Bulk chemical analyses of specific grain size fractions were also carried out. The finest sizes ( 10 microns) display generally the strongest enrichment/depletion factors. Similar, if not exactly identical, trends are reported from lunar soils. It is, therefore, not necessarily correct to explain the chemical characteristics of various grain sizes via different admixtures of materials from distant source terrains. Differential comminution of local source rocks may be the dominating factor.

Silk fiber for in-tube solid-phase microextraction to detect aldehydes by chemical derivatization.

PubMed

Wang, Xiuqin; Pan, Lei; Feng, Juanjuan; Tian, Yu; Luo, Chuannan; Sun, Min

2017-11-03

Aldehydes are the potentially damaging pollutants in the environment, but it is difficult to be determined due to the low concentration level. Therefore, to accurate analysis of aldehydes, it is important for efficient sample preparation with selective enrichment and rapid separation. Environmentally friendly silk fiber as adsorbent material was directly applied to develop in-tube solid-phase microextraction for analyzing aqueous samples combined with high performance liquid chromatography. 2,4-Dinitrophenylhydrazine as a derivative reagent was used for chemical derivatization of aldehydes before extraction. Under optimum conditions, an online analysis method was built with the limits of detection in the range of 0.005-0.01μgL -1 and the linearity in the range of 0.03-10μgL -1 . Three aldehydes were determined in two real samples, and the relative recoveries were in the range of 95-102%. Copyright © 2017 Elsevier B.V. All rights reserved.

Tough and deformable glasses with bioinspired cross-ply architectures.

PubMed

Yin, Zhen; Dastjerdi, Ahmad; Barthelat, Francois

2018-05-15

Glasses are optically transparent, hard materials that have been in sustained demand and usage in architectural windows, optical devices, electronics and solar panels. Despite their outstanding optical qualities and durability, their brittleness and low resistance to impact still limits wider applications. Here we present new laminated glass designs that contain toughening cross-ply architectures inspired from fish scales and arthropod cuticles. This seemingly minor enrichment completely transforms the way laminated glass deforms and fractures, and it turns a traditionally brittle material into a stretchy and tough material with little impact on surface hardness and optical quality. Large ply rotation propagates over large volumes, and localization is delayed in tension, even if a strain softening interlayer is used, in a remarkable mechanism which is generated by the kinematics of the plies and geometrical hardening. Compared to traditional laminated glass which degrades significantly in performance when damaged, our cross-ply architecture glass is damage-tolerant and 50 times tougher in energy terms. Despite the outstanding optical qualities and durability of glass, its brittleness and low resistance to impact still limits its wider application. Here we present new laminated glass designs that contain toughening cross-ply architectures inspired from fish scales and arthropod cuticles. Enriching laminated designs with crossplies completely transforms the material deforms and fractures, and turns a traditionally brittle material into a stretchy and tough material - with little impact on surface hardness and optical quality. Large ply rotation propagates over large volumes and localization is delayed in tension because of a remarkable and unexpected geometrical hardening effect. Compared to traditional laminated glass which degrades significantly in performance when damaged, our cross-ply architecture glass is damage-tolerant and it is 50 times tougher in energy terms. Our glass-based, transparent material is highly innovative and it is the first of its kind. We believe it will have impact in broad range of applications in construction, coatings, chemical engineering, electronics, photovoltaics. Copyright © 2018. Published by Elsevier Ltd.

Chemical Mobility, Variability, and Components of the Yaxcopoil Impact Melt Breccia Matrix as a Function of Depth

NASA Astrophysics Data System (ADS)

Nelson, M. J.; Newsom, H.

2005-05-01

The matrix in the Yaxcopoil 1 drill core produced by the Chicxulub event is semi-amorphous, containing clays and evidence for elemental mobility. We analyzed matrix in impact melt and suevitic breccia samples from the drill hole to detect mineralogical and chemical variability with depth in upper and lower core samples. SEM, microprobe, Cameca 4f ion probe, and XRD were used to determine chemical mobility and variation, and clay structure in several YAX samples, covering the top five units, at a depth range of about 61m. We investigated the possibility of glass, clay, and metastable eutectic dehydroxylates as components in the matrix. Matrix in upper suevite is not optically distinct, but a type of groundmass, with an admixture of calcite, crystallites, and several melt phases with melt texture indicative of simultaneous formation. With an increase in depth, flow tex-ture in the melt matrix is obvious around clasts on all scales, indicating a different temporal relationship than in the upper suevite. Chemically, the matrix is Si and Mg rich in most samples. With an increase in depth, the bulk matrix contains a strong linear increase of Mg, and a decrease of Al. With depth, the increasingly Mg-rich matrix exhibits a stronger flow texture. Aluminum also appears mobile, with enrichments mostly around clasts and veins. In addition, Li and B are strongly correlated, and decrease linearly with depth. The matrix contains materials that appear to be chemically and structurally consistent with smectites at all depths. The compositions range from that of an average montmorillonite in the uppermost units to that of a magnesium rich saponite in the lower units. Aside from the exis-tence of clays, we are considering the possibility that the matrix could contain metastable condensates from the im-pact dust cloud. As an introductory step to test this, matrix compositions were plotted among metastable eutectic dehydroxylate (MED) end members. This produced a remarkably co-linear trend with the join between MED pyro-phyllite and MED serpentine. High resolution equipment will be used to follow up on this idea. The matrix in lower samples had more element mobility, and likely more chemical reactions occurring among phases. An increase in mobility and transport of Mg could help explain this bulk enrichment in lower samples. In addition, variations in the original target material would logically contribute to chemical variations in the matrix. Dolomite and mafic minerals present at greater depth could react with matrix in the melt breccia, while dust and clay may exist in variable amounts within the drill core samples. The linear trend toward metastable dehydroxylate eutec-tic compositions is an encouraging first step to further investigate the possible existence of condensates from the impact cloud within the matrix.

Chemical Enrichment History Of Abell 3112 Galaxy Cluster Out To The Virial Radius

NASA Astrophysics Data System (ADS)

Ezer, C.; Bulbul, E.; Ercan, E.; Smith, R.; Bautz, M.; Loewenstein, M.; McDonald, M.; Miller, E.

2017-10-01

The deep potential well of the galaxy clusters confines all metals produced via supernova explosions within the intra-cluster medium (ICM). The radial distributions of these metals along the ICM are direct records of the metal enrichment history. In this work, we investigate the chemical enrichment history of Abell 3112 galaxy cluster from cluster's core to out to radius R_{200} (˜ 1470 kpc) by analyzing a deep 1.2 Ms Suzaku observations with overlapping 72 ks Chandra observations. The fraction of supernova explosions enriching the ICM is obtained by fitting the X-ray spectra with a robust snapec model implemented in XSPEC. The ratio of supernova type Ia explosions to the core collapse supernova explosions is found in the range 0.12 - 0.16 and uniformly distributed out to R_{200}. The uniform spatial distribution of supernova enrichment indicates an early metal enrichment between the epoch of z ˜ 2 - 3. We also observe that W7, CDD, and WDD SN Ia models equally better explain the highest signal-to-noise region compared to 2D delayed detonation model CDDT. We further report the first time temperature (3.37 ± 0.77 keV) and metallicity (0.22 ± 0.08 Z_{⊙}) measurements of this archetypal cluster at its virial radius.

16. VIEW OF THE ENRICHED URANIUM RECOVERY SYSTEM. ENRICHED URANIUM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. VIEW OF THE ENRICHED URANIUM RECOVERY SYSTEM. ENRICHED URANIUM RECOVERY PROCESSED RELATIVELY PURE MATERIALS AND SOLUTIONS AND SOLID RESIDUES WITH RELATIVELY LOW URANIUM CONTENT. URANIUM RECOVERY INVOLVED BOTH SLOW AND FAST PROCESSES. (4/4/66) - Rocky Flats Plant, General Manufacturing, Support, Records-Central Computing, Southern portion of Plant, Golden, Jefferson County, CO

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... enrichment facilities. 140.13b Section 140.13b Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) FINANCIAL... required for uranium enrichment facilities. Each holder of a license issued under Parts 40 or 70 of this chapter for a uranium enrichment facility that involves the use of source material or special nuclear...

Geochemical Diversity of the Mantle: 50 Years of Acronyms

NASA Astrophysics Data System (ADS)

Hart, S. R.

2014-12-01

50 years ago, Gast, Tilton and Hedge demonstrated that the oceanic mantle is isotopically heterogeneous. 28 years ago, Zindler and Hart formalized the concept of geochemical mantle components, with an attendant, to some, odious, acronym soup. Work on a marriage of mantle geochemistry and dynamics continues unabated. We know unequivocally that the mantle is chemically heterogeneous; we do not know the scale lengths of these heterogeneities. We know unequivocally that these heterogeneities have persisted for eons (Gy); we do not know where they were formed or where they are stored. Through the kind auspices of the Plume Model, we plausibly have access to the whole mantle. The most accessible and well understood mantle reservoir is the upper depleted MORB mantle (DMM). Classically, this mantle was depleted by extraction of oceanic and continental crust from a "chondritic" bulk silicate Earth. In this post-Boyet and Carlson world, the complementary enriched reservoir may instead be hidden in the deepest mantle. In this case, DMM will become an endangered acronym. Hofmann and White (1982) argued that radiogenic Pb mantle (HIMU) is re-cycled ocean crust, and this is a comfortably viable model. It does require some ad hoc chemical manipulations during subduction. Given 2 Gy of aggregate mantle strains, the mafic component in HIMU may be of small length scale (< 50 m), possibly subsumed into the dominant peridotitic lithology. This mantle species is globally widespread. Enriched mantles (EM1 and EM2) almost certainly reflect recycling of enriched continental material. This was splendidly verified by Jackson et al (2007), with 87Sr/86Sr in Samoan EM2 lavas up to 0.721. The lithology and length scale of EM1 and EM2 is unconstrained. EM1 is globally present; EM2 is confined to the SW Pacific hotspots. FOZO is a work in progress; many would like to see it become extinct! The trace element signatures of HIMU and FOZO mantles have been constrained using melting models; in both cases the spidergrams are "enriched" with peaks at Nb-Ta of 2x and 4x bulk silicate earth, respectively, but with quite different shapes. As is typical with OIB, the derived source compositions are incompatible with the isotopic signatures, requiring a fairly recent "enrichment" event (possibly auto-metasomatism).

Astrophysics with Extraterrestrial Materials

NASA Astrophysics Data System (ADS)

Nittler, Larry R.; Ciesla, Fred

2016-09-01

Extraterrestrial materials, including meteorites, interplanetary dust, and spacecraft-returned asteroidal and cometary samples, provide a record of the starting materials and early evolution of the Solar System. We review how laboratory analyses of these materials provide unique information, complementary to astronomical observations, about a wide variety of stellar, interstellar and protoplanetary processes. Presolar stardust grains retain the isotopic compositions of their stellar sources, mainly asymptotic giant branch stars and Type II supernovae. They serve as direct probes of nucleosynthetic and dust formation processes in stars, galactic chemical evolution, and interstellar dust processing. Extinct radioactivities suggest that the Sun's birth environment was decoupled from average galactic nucleosynthesis for some tens to hundreds of Myr but was enriched in short-lived isotopes from massive stellar winds or explosions shortly before or during formation of the Solar System. Radiometric dating of meteorite components tells us about the timing and duration over which solar nebula solids were assembled into the building blocks of the planets. Components of the most primitive meteoritical materials provide further detailed constraints on the formation, processing, and transport of material and associated timescales in the Sun's protoplanetary disk as well as in other forming planetary systems.

Lunar material resources: An overview

NASA Technical Reports Server (NTRS)

Carter, James L.

1992-01-01

The analysis of returned lunar samples and a comparison of the physical and chemical processes operating on the Moon and on the Earth provide a basis for predicting both the possible types of material resources (especially minerals and rocks) and the physical characteristics of ore deposits potentially available on the Moon. The lack of free water on the Moon eliminates the classes of ore deposits that are most exploitable on Earth; namely, (1) hydrothermal, (2) secondary mobilization and enrichment, (3) precipitation from a body of water, and (4) placer. The types of lunar materials available for exploitation are whole rocks and their contained minerals, regolith, fumarolic and vapor deposits, and nonlunar materials, including solar wind implantations. Early exploitation of lunar material resources will be primarily the use of regolith materials for bulk shielding; the extraction from regolith fines of igneous minerals such as plagioclase feldspars and ilmenite for the production of oxygen, structural metals, and water; and possibly the separation from regolith fines of solar-wind-implanted volatiles. The only element, compound, or mineral, that by itself has been identified as having the economic potential for mining, processing, and return to Earth is helium-3.

Derivatized graphitic nanofibres (GNF) as a new support material for mass spectrometric analysis of peptides and proteins.

PubMed

Greiderer, Andreas; Rainer, Matthias; Najam-ul-Haq, Muhammad; Vallant, Rainer M; Huck, Christian W; Bonn, Günther K

2009-07-01

Graphitic nanofibres (GNFs), 100-200 nm in diameter and 5-20 microm in length have been modified in order to yield different affinities (Cu2+ and Fe3+ loaded immobilized metal affinity chromatography (IMAC) as well as cation and anion exchange materials) for the extraction of a range of biomolecules by their inherited hydrophobicity and the hydrophilic chemical functionalities, obtained by derivatization. Modified GNFs have for the first time been employed as carrier materials for protein profiling in material-enhanced laser desorption/ionization (MELDI) for the enrichment and screening of biofluids. For that purpose, the derivatized GNF materials have comprehensively been characterized regarding surface area, structural changes during derivatization, IMAC, as well as ion exchange and protein-loading capacity and recovery. GNF derivatives revealed high protein-binding capacity (2,000 microg ml(-1) for insulin) and ideal sensitivities, resulting in a detection limit of 50 fmol microl(-1) (for insulin), which is crucial for the detection of low abundant species in biological samples. Compared to other MELDI carrier materials, sensitivity was enhanced on GNF derivatives, which might be ascribed to the fact that GNFs support desorption and ionization mechanisms and by absorbing laser energy in addition to matrix.

Effect of saffron (Crocus sativus L.) enrichment on antioxidant and sensorial properties of wheat flour pasta.

PubMed

Armellini, R; Peinado, I; Pittia, P; Scampicchio, M; Heredia, A; Andres, A

2018-07-15

Saffron, used in cookery as a flavouring and colouring agent, is well-known for its antioxidant and beneficial health properties. In the present work, the effect of saffron addition (0-control, 0.1, 0.2 and 0.4%, w/w) in the formulation of fresh pasta was evaluated on textural, physical-chemical, and sensory properties of the cooked product. Content and retention of the bioactive molecules of saffron (crocins) were evaluated by HPLC along with the corresponding antioxidant activity of enriched pasta. The presence of saffron significantly influenced textural and physical-chemical properties of pasta. Higher saffron concentrations enhanced the antioxidant activity of pasta with the higher values of crocins in samples enriched with 0.4% saffron extract even after 3 min of cooking (4.23-5.06 mg/g db). Sensory analysis showed an increased acceptability of the saffron enriched pasta for all descriptors selected (visual aspect, colour, aroma, taste, chewiness, hardness, gumminess and overall acceptability). Copyright © 2018 Elsevier Ltd. All rights reserved.

Rapid bacteriological screening of cosmetic raw materials by using bioluminescence.

PubMed

Nielsen, P; Van Dellen, E

1989-01-01

Incoming cosmetic raw materials are routinely tested for microbial content. Standard plate count methods require up to 72 h. A rapid, sensitive, and inexpensive raw material screening method was developed that detects the presence of bacteria by means of ATP (bioluminescence). With a 24-h broth enrichment, the minimum bacterial ATP detection threshold of 1 cfu/g sample can be achieved using purified firefly luciferin-luciferase and an ATP releasing reagent. By using this rapid screen, microbiologically free material may be released for production within 24 h, while contaminated material undergoes further quantitative and identification testing. In order for a raw material to be validated for this method it must be evaluated for (1) a potential nonmicrobial light-contributing reaction resulting in a false positive or, (2) degradation of the ATP giving a false negative, and (3) confirmation that the raw material has not overwhelmed the buffering capacity of the enrichment broth. The key criteria for a rapid screen was the sensitivity to detect less than one colony forming unit per g product, the speed to do this within 24 h, and cost efficiency. Bioluminescence meets these criteria. With an enrichment step, it can detect less than one cfu/g sample. After the enrichment step, analysis time per sample is approximately 2 min and the cost for material and reagents is less than one dollar per sample.

[Research on resources chemistry of Chinese medicinal materials and resources recycling utilization ways and goals and tasks].

PubMed

Duan, Jin-ao; Su, Shu-lan; Guo, Sheng; Jiang, Shu; Liu, Pei; Yan, Hui; Qian, Da-wei; Zhu, Hua-xu; Tang, Yu-ping; Wu, Qi-nan

2015-09-01

The objects of research on the resources chemistry of Chinese medicinal materials (RCCMM) are promotion of efficient production, rational utilization and improving quality of CMM and natural products. The development of TCM cause depends on the efficient utilization and sustainable development of CMM, hinges on the technologies and methods for using and discovering medicinal biological resources, stand or fall on the extension of industy chains, detailed utilizaion of resource chemical components by multi-way, multi-level. All of these may help to the recycling utilization and sound development of RCMM. In this article, five respects were discussed to the RCCMM researches and resources recycling utilization ways and goals and tasks. First, based on the principle of resource scarcity, discovering or replacing CMM resources, protecting the rare or endangered species or resources. Second, based on the multifunctionality of CMM, realizing the value-added and value compensation, and promoting the utilization efficiency through systermatic and detailed exploitation and utilization. Third, based on the resource conservation and environment-friendly, reducing raw material consumption, lowering cost, promoting recycling utilization and elevating utilization efficiency. Fourth, based on the stratege of turning harm into good, using the invasive alien biological resources by multi-ways and enriching the medicial resources. Fifth, based on the method of structure modification of chemical components, exploring and enhancing the utility value of resouces chemical substances. These data should provide references and attention for improving the utilization efficiency, promoting the development of recycling economy, and changing the mode of economic growth of agriculture and industry of CMM fundamentally.

Achieving biopolymer synergy in systems chemistry.

PubMed

Bai, Yushi; Chotera, Agata; Taran, Olga; Liang, Chen; Ashkenasy, Gonen; Lynn, David G

2018-05-31

Synthetic and materials chemistry initiatives have enabled the translation of the macromolecular functions of biology into synthetic frameworks. These explorations into alternative chemistries of life attempt to capture the versatile functionality and adaptability of biopolymers in new orthogonal scaffolds. Information storage and transfer, however, so beautifully represented in the central dogma of biology, require multiple components functioning synergistically. Over a single decade, the emerging field of systems chemistry has begun to catalyze the construction of mutualistic biopolymer networks, and this review begins with the foundational small-molecule-based dynamic chemical networks and peptide amyloid-based dynamic physical networks on which this effort builds. The approach both contextualizes the versatile approaches that have been developed to enrich chemical information in synthetic networks and highlights the properties of amyloids as potential alternative genetic elements. The successful integration of both chemical and physical networks through β-sheet assisted replication processes further informs the synergistic potential of these networks. Inspired by the cooperative synergies of nucleic acids and proteins in biology, synthetic nucleic-acid-peptide chimeras are now being explored to extend their informational content. With our growing range of synthetic capabilities, structural analyses, and simulation technologies, this foundation is radically extending the structural space that might cross the Darwinian threshold for the origins of life as well as creating an array of alternative systems capable of achieving the progressive growth of novel informational materials.

Chemical Composition of Rocks and Soils at Gusev and Meridiani Landing Sites of the Mars Exploration Rovers: APXS Results and Implications.

NASA Astrophysics Data System (ADS)

Zipfel, J.; Team, A. S.

2004-12-01

The Alpha-Particle X-ray Spectrometers (APXS) are part of the instrument suites of both Mars Exploration Rovers, Spirit and Opportunity, which landed on Mars at Gusev crater and Meridiani Planum in the beginning of 2004. They are in-situ instruments for the determination of major and minor elements of soils, rocks, and outcrops. Soils at these landing sites are chemically characterized by high sulfur and chlorine contents, similar to soils at previous landing sites. Abundances of major and minor elements of all soils are very similar, strongly supporting the concept of global distribution and thorough mixing of soils on Mars. Locally, minor deviations from average soil composition are observed. These are attributed to the addition of local components to "global soil". In one trench at Gusev crater magnesium and sulfur concentrations increase with depth and give direct evidence for magnesium sulfate, possibly formed by weathering of olivine under acidic conditions, and local redistribution processes. Rocks at Gusev crater plains are primitive magnesium-rich basaltic rocks with normative olivine. They are coated to varying degrees with soil/dust and alteration rinds. Highly mobile elements are enriched in these outer layers. Outcrop materials at the base of the Colombia Hill site are possibly basaltic or volcaniclastic rocks. They are chemically highly altered as reflected by very high concentrations of water soluble elements (S, Cl, and Br), observed even after removal of a more than 8 mm thick surface layer. Apparently, the alteration extends to much greater depth. Outcrops at the Opportunity landing site were analyzed in Eagle crater and Endurance crater. These are light-toned sedimentary rocks of siliciclastic materials with up to 40 weight percent of sulfates. Based on mass balance calculations, in addition to Mg-sulfate and jarosite, other sulfates, e.g., Ca- and Al-bearing sulfates must be present. Outcrop rocks in Eagle crater are enriched in bromine relative to chlorine to varying degrees. Rocks in Endurance crater are stratigraphically layered sediments, possibly deposited under aqueous and aeolian conditions. The silicate to sulfate ratio of these units increases with depth. Vein fillings have high bromine concentrations. The chemical composition of rocks, soils and outcrops analyzed at both landing sites provides clear evidence for water-rock interaction and the presence of water over an extended period of time.

Bio-solid-State processes for synthesis of Li-Fe-phosphate.

PubMed

Kim, Hyoung-Bum; Park, Byungno; Lee, Insung; Roh, Yul

2008-10-01

Lithium-Fe-phosphates have become of great interest as storage cathodes for rechargeable Li-batteries because of their high density, environmental friendliness, and safety. The objective of this study was to examine bio-solid-state synthesis of LiFePO4 by microbial processes at room temperature. The microbial reduction of Fe(III)-citrate using an organic carbon, glucose, as an electron donor in the presence of NaHPO4 and lithium that resulted in the formation of Li-substituted iron phosphate. Our studies showed that bacteria enriched from inter-tidal flat sediments, designated as Haejae-1, synthesized Li-substituted iron phosphate. Characterization by X-ray diffraction showed the reduction of Fe(III)-citrate in the presence of NaHPO4 and LiCl2 resulted in the precipitation of Li-substituted vivianite [Li(x)Fe(3-x)(PO4)2 x 8H2O]. SEM-EDX, FTIR, and ESCA analyses showed the chemical composition of the synthesized phases was Li, Fe, P, C, and O. Based on the chemical and physical structure of the mineral, the novel bio-nano-material may be potentially useful to the development of energy storage materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Jonell Nicole; White, Michael Irvin; Bernstein, Robert

Chemical structure and physical properties of materials, such as polymers, can be altered as aging progresses, which may result in a material that is ineffective for its envisioned intent. Butyl rubber formulations, starting material, and additives were aged under thermal-oxidative conditions for up to 413 total days at up to 124 ÀC. Samples included: two formulations developed at Kansas City Plant (KCP) (#6 and #10), one commercially available formulation (#21), Laxness bromobutyl 2030 starting material, and two additives (polyethylene AC-617 and Vanax MBM). The low-molecular weight volatile thermal-oxidative degradation products that collected in the headspace over the samples were preconcentrated,more » separated, and detected using cryofocusing gas chromatography mass spectrometry (cryo-GC/MS). The majority of identified degradation species were alkanes, alkenes, alcohols, ketones, and aldehydes. Observations for Butyl #10 aged in an oxygen-18 enriched atmosphere (18O2) were used to verify when the source of oxygen in the applicable degradation products was from the gaseous environment rather than the polymeric mixture. For comparison purposes, Butyl #10 was also aged under non-oxidative thermal conditions using an argon atmosphere.« less

Magmatic and fragmentation controls on volcanic ash surface chemistry

NASA Astrophysics Data System (ADS)

Ayris, Paul M.; Diplas, Spyros; Damby, David E.; Hornby, Adrian J.; Cimarelli, Corrado; Delmelle, Pierre; Scheu, Bettina; Dingwell, Donald B.

2016-04-01

The chemical effects of silicate ash ejected by explosive volcanic eruptions on environmental systems are fundamentally mediated by ash particle surfaces. Ash surfaces are a composite product of magmatic properties and fragmentation mechanisms, as well as in-plume and atmospheric alteration processes acting upon those surfaces during and after the eruption. Recent attention has focused on the capacity of alteration processes to shape ash surfaces; most notably, several studies have utilised X-ray photoelectron spectroscopy (XPS), a technique probing the elemental composition and coordination state of atoms within the top 10 nm of ash surfaces, to identify patterns of elemental depletions and enrichments relative to bulk ash chemical composition. Under the presumption of surface and bulk equivalence, any disparities have been previously attributed to surface alteration processes, but the ubiquity of some depletions (e.g., Ca, Fe) across multiple ash studies, irrespective of eruptive origin, could suggest these to be features of the surface produced at the instant of magma fragmentation. To investigate this possibility further, we conducted rapid decompression experiments at different pressure conditions and at ambient and magmatic temperature on porous andesitic rocks. These experiments produced fragmented ash material untouched by secondary alteration, which were compared to particles produced by crushing of large clasts from the same experiments. We investigated a restricted size fraction (63-90 μm) from both fragmented and crushed materials, determining bulk chemistry and mineralogy via XRF, SEM-BSE and EPMA, and investigated the chemical composition of the ash surface by XPS. Analyses suggest that fragmentation under experimental conditions partitioned a greater fraction of plagioclase-rich particles into the selected size fraction, relative to particles produced by crushing. Trends in surface chemical composition in fragmented and crushed particles mirror that partitioning effect, but crucially, disparities between surface and bulk chemistry remain evident. Simple glass-plagioclase mixing calculations suggest that this feature may indicate differences in bulk and surface mineral distributions; future QEMSCAN analysis will investigate this possibility further. Additionally, surface iron enrichments observed in our high temperature experiments suggest that hot oxidation effects can have a near-instantaneous, measurable effect on ash surface chemistry at the nanometre scale. Our preliminary results suggest that the chemical and mineral properties of the source magma, coupled with high temperature fragmentation processes, may have a significant influence on ash surface chemistry and mineralogy, and subsequently, on the post-eruptive alteration of ash particles and their reactivity within biotic and abiotic systems.

The population of planetary nebulae near the Galactic Centre: chemical abundances

NASA Astrophysics Data System (ADS)

Mollá, M.; Cavichia, O.; Costa, R. D. D.; Maciel, W. J.

2017-10-01

In this work, we report physical parameters and abundances derived for a sample of 15 high extinction planetary nebulae located in the inner 2° of the Galactic bulge, based on low dispersion spectroscopy secured at the SOAR telescope using the Goodman spectrograph. The new data allow us to extend our database including older, weaker objects that are at the faint end of the planetary nebulae luminosity function. The data provide chemical compositions for PNe located in this region of the bulge to explore the chemical enrichment history of the central region of the Galactic bulge. The results show that the abundances of our sample are skewed to higher metallicities than previous data in the outer regions of the bulge. This can indicate a faster chemical enrichment taking place at the Galactic centre.

The Chemical Compositions of the SRD Variable Stars. III. KK Aquilae, AG Aurigae, Z Aurigae, W Leo Minoris, and WW Tauri

NASA Astrophysics Data System (ADS)

Giridhar, Sunetra; Lambert, David L.; Gonzalez, Guillermo

2000-12-01

Chemical compositions are derived from high-resolution spectra for five field SRd variables. These supergiants not previously analyzed are shown to be metal poor: KK Aql with [Fe/H]=-1.2, AG Aur with [Fe/H]=-1.8, Z Aur with [Fe/H]=-1.4, W LMi with [Fe/H]=-1.1, and WW Tau with [Fe/H]=-1.1. Their compositions are, except for two anomalies, identical to within the measurement errors to the compositions of subdwarfs, subgiants, and less evolved giants of the same [Fe/H]. One anomaly is an s-process enrichment for KK Aql, the first such enrichment reported for an SRd variable. The second and more remarkable anomaly is a strong lithium enrichment for W LMi, also a first for field SRd variables. The Li I λ6707 profile is not simply that of a photospheric line but includes strong absorption from redshifted gas, suggesting, perhaps, that lithium enrichment results from accretion of Li-rich gas. This potential clue to lithium enrichment is discussed in light of various proposals for lithium synthesis in evolved stars.

Chemical Applications for Enhanced World Security

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leibman, Christopher Patrick

The purpose of this project is to reduce complexity of chemical analysis by combining chemical and physical processing steps into on package; develop instrumentation that cost less and is easy to use in a field laboratory by non-experts; and develop this "chemical application" so uranium enrichment can be measured onsite, eliminating the need for radioactive sample transport.

Interdisciplinary Characterizations of Models and the Nature of Chemical Knowledge in the Classroom

ERIC Educational Resources Information Center

Erduran, Sibel; Duschl, Richard A.

2004-01-01

In this paper, the authors argue that chemical knowledge in the classroom will be enriched by the application of characterizations of models drawn from a range of disciplinary backgrounds. This discussion highlights two important issues relating to chemical knowledge in the classroom: (1) the status of chemical knowledge in the classroom,…

Preserving Plutonium-244 as a National Asset

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patton, Bradley D; Alexander, Charles W; Benker, Dennis

Plutonium-244 (244 Pu) is an extremely rare and long-lived isotope of plutonium with a half-life of 80 million years. Measureable amounts of 244 Pu are found in neither reactor-grade nor weapons-grade plutonium. Production of this isotope requires a very high thermal flux to permit the two successive neutron captures that convert 242 Pu to 243 Pu to 244 Pu, particularly given the short (about 5 hour) half-life of 243 Pu. Such conditions simply do not exist in plutonium production processes. Therefore, 244 Pu is ideal for precise radiochemical analyses measuring plutonium material properties and isotopic concentrations in items containing plutonium.more » Isotope dilution mass spectrometry is about ten times more sensitive when using 244 Pu rather than 242 Pu for determining plutonium isotopic content. The isotope can also be irradiated in small quantities to produce superheavy elements. The majority of the existing global inventory of 244 Pu is contained in the outer housing of Mark-18A targets at the Savannah River Site (SRS). The total inventory is about 20 grams of 244 Pu in about 400 grams of plutonium distributed among the 65 targets. Currently, there are no specific plans to preserve these targets. Although the cost of separating and preserving this material would be considerable, it is trivial in comparison to new production costs. For all practical purposes, the material is irreplaceable, because new production would cost billions of dollars and require a series of irradiation and chemical separation cycles spanning up to 50 years. This paper will discuss a set of options for overcoming the significant challenges to preserve the 244 Pu as a National Asset: (1) the need to relocate the material from SRS in a timely manner, (2) the need to reduce the volume of material to the extent possible for storage, and (3) the need to establish an operational capability to enrich the 244 Pu in significant quantities. This paper suggests that if all the Mark-18A plutonium is separated, it would occupy a small volume and would be inexpensive to store while an enrichment capability is developed. Very small quantities could be enriched in existing mass separators to support critical needs.« less

Production and application of O2 enriched air produced by fresh and salt water desorption in chemical plants.

PubMed

Galli, F; Previtali, D; Bozzano, G; Bianchi, C L; Manenti, F; Pirola, C

2018-07-01

Oxygen enriched air intensifies oxidation processes since smaller reactors reach the same conversion of typical unit operations that employ simple air as reactant. However, the cost to produce pure oxygen or oxygen enriched air with traditional methods, i.e. cryogenic separation or membrane technologies, may be unaffordable. Here, we propose a new continuous technology for gas mixture separation, focusing on the production of oxygen enriched air as a case study. This operation is an absorption-desorption process that takes advantage of the higher oxygen solubility in water compared to nitrogen. In a pressurized solubilisation tank, water absorbs air. Subsequently, reducing pressure desorbs oxygen enriched air. PRO/II 9.3 (Simsci-Scheider Electrics) simulated, optimized, and calculated the capital and operative expenses of this technology. Moreover, we tested for the first time salt water instead of distilled water as appealing possibility for chemical plant near sea and ocean. We varied the inlet water flowrate between 5 and 15 m 3 /h. The optimum operative absortion unit pressure is 15-35 barg. After degassing, water may be recycled. With salt water, the extracted quantity of enriched air decreases compared with the desorption from fresh water (20% less), while the concentration of oxygen is independent from the salt concentration. The cost of enriched air at the optimum condition is 2-3.35 EUR/Nm 3 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Routine inspection effort required for verification of a nuclear material production cutoff convention

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dougherty, D.; Fainberg, A.; Sanborn, J.

On 27 September 1993, President Clinton proposed {open_quotes}... a multilateral convention prohibiting the production of highly enriched uranium or plutonium for nuclear explosives purposes or outside of international safeguards.{close_quotes} The UN General Assembly subsequently adopted a resolution recommending negotiation of a non-discriminatory, multilateral, and internationally and effectively verifiable treaty (hereinafter referred to as {open_quotes}the Cutoff Convention{close_quotes}) banning the production of fissile material for nuclear weapons. The matter is now on the agenda of the Conference on Disarmament, although not yet under negotiation. This accord would, in effect, place all fissile material (defined as highly enriched uranium and plutonium) produced aftermore » entry into force (EIF) of the accord under international safeguards. {open_quotes}Production{close_quotes} would mean separation of the material in question from radioactive fission products, as in spent fuel reprocessing, or enrichment of uranium above the 20% level, which defines highly enriched uranium (HEU). Facilities where such production could occur would be safeguarded to verify that either such production is not occurring or that all material produced at these facilities is maintained under safeguards.« less

Application of new insoluble dietary fibres from triticale as supplement in yoghurt - effects on physico-chemical, rheological and quality properties.

PubMed

Miocinovic, Jelena; Tomic, Nikola; Dojnov, Biljana; Tomasevic, Igor; Stojanovic, Sanja; Djekic, Ilija; Vujcic, Zoran

2018-03-01

The need to increase the daily intake of dietary fibres opens a new chapter in the research of functional foods enriched with fibres. The potential application of an innovative product - insoluble dietary fibres from triticale in yoghurts - was deployed by characterising their food application and evaluating physico-chemical, rheological and sensory properties and was the aim of this research. Detailed characterisations of these fibres are presented for the first time and showed very good hydration properties, optimal pH (slightly acidic), optimal chemical composition, high antioxidant capacity which was proven by phenolics contents. Besides, these fibres showed negligible calorific value, with no phytates and high antioxidant capacity, mainly from ferulic acid. Therefore they could be successfully added to yoghurt. Enrichment of yoghurt having different milk fat content (1.5 and 2.8% w/w) with triticale insoluble fibre (1.5% and 3.0% w/w) significantly influenced the syneresis level, its apparent viscosity, yield stress and thixotropic behaviour. The overall sensory quality scores indicated that yoghurt enriched with 1.5% triticale insoluble fibres was recognised as 'excellent' and had enhanced antioxidant activity. Insoluble triticale fibre could therefore be used as a supplement to produce functional yoghurt. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Novel High-Fidelity Screening of Environmental Chemicals and Carcinogens and Mechanisms in Colorectal Cancer.

DTIC Science & Technology

2016-09-01

Chemical Promiscuity, Pharmacokinetics, Colorectal Cancer, N , N ’-disalicylidene-1,2-diaminopropane, Pyraclostrobin, Paclobutrazol, Vitamin D Receptor, Wnt...Environmental Chemicals, TOX-TMFS, CPTM, Cancer Cellular Network Model, Chemical Reactivity, Chemical Promiscuity, Pharmacokinetics, Colorectal Cancer, N , N ...network models were further enriched with oncologic disease OMIM profiles to create cancer-specific networks. The ECs N , N ’-disalicylidene- 1,2

An extremely primitive star in the Galactic halo.

PubMed

Caffau, Elisabetta; Bonifacio, Piercarlo; François, Patrick; Sbordone, Luca; Monaco, Lorenzo; Spite, Monique; Spite, François; Ludwig, Hans-G; Cayrel, Roger; Zaggia, Simone; Hammer, François; Randich, Sofia; Molaro, Paolo; Hill, Vanessa

2011-08-31

The early Universe had a chemical composition consisting of hydrogen, helium and traces of lithium; almost all other elements were subsequently created in stars and supernovae. The mass fraction of elements more massive than helium, Z, is known as 'metallicity'. A number of very metal-poor stars has been found, some of which have a low iron abundance but are rich in carbon, nitrogen and oxygen. For theoretical reasons and because of an observed absence of stars with Z < 1.5 × 10(-5), it has been suggested that low-mass stars cannot form from the primitive interstellar medium until it has been enriched above a critical value of Z, estimated to lie in the range 1.5 × 10(-8) to 1.5 × 10(-6) (ref. 8), although competing theories claiming the contrary do exist. (We use 'low-mass' here to mean a stellar mass of less than 0.8 solar masses, the stars that survive to the present day.) Here we report the chemical composition of a star in the Galactic halo with a very low Z (≤ 6.9 × 10(-7), which is 4.5 × 10(-5) times that of the Sun) and a chemical pattern typical of classical extremely metal-poor stars--that is, without enrichment of carbon, nitrogen and oxygen. This shows that low-mass stars can be formed at very low metallicity, that is, below the critical value of Z. Lithium is not detected, suggesting a low-metallicity extension of the previously observed trend in lithium depletion. Such lithium depletion implies that the stellar material must have experienced temperatures above two million kelvin in its history, given that this is necessary to destroy lithium.

Interaction of ordinary Portland cement and Opalinus Clay: Dual porosity modelling compared to experimental data

NASA Astrophysics Data System (ADS)

Jenni, A.; Gimmi, T.; Alt-Epping, P.; Mäder, U.; Cloet, V.

2017-06-01

Interactions between concrete and clays are driven by the strong chemical gradients in pore water and involve mineral reactions in both materials. In the context of a radioactive waste repository, these reactions may influence safety-relevant clay properties such as swelling pressure, permeability or radionuclide retention. Interfaces between ordinary Portland cement and Opalinus Clay show weaker, but more extensive chemical disturbance compared to a contact between low-pH cement and Opalinus Clay. As a consequence of chemical reactions porosity changes occur at cement-clay interfaces. These changes are stronger and may lead to complete pore clogging in the case of low-pH cements. The prediction of pore clogging by reactive transport simulations is very sensitive to the magnitude of diffusive solute fluxes, cement clinker chemistry, and phase reaction kinetics. For instance, the consideration of anion-depleted porosity in clays substantially influences overall diffusion and pore clogging at interfaces. A new concept of dual porosity modelling approximating Donnan equilibrium is developed and applied to an ordinary Portland cement - Opalinus Clay interface. The model predictions are compared with data from the cement-clay interaction (CI) field experiment in the Mt Terri underground rock laboratory (Switzerland), which represent 5 y of interaction. The main observations such as the decalcification of the cement at the interface, the Mg enrichment in the clay detached from the interface, and the S enrichment in the cement detached from the interface, are qualitatively predicted by the new model approach. The model results reveal multiple coupled processes that create the observed features. The quantitative agreement of modelled and measured data can be improved if uncertainties of key input parameters (tortuosities, reaction kinetics, especially of clay minerals) can be reduced.

Developing 226Ra and 227Ac age-dating techniques for nuclear forensics to gain insight from concordant and non-concordant radiochronometers

DOE PAGES

Kayzar, Theresa M.; Williams, Ross W.

2015-09-26

The model age or ‘date of purification’ of a nuclear material is an important nuclear forensic signature. In this study, chemical separation and MC-ICP-MS measurement techniques were developed for 226 Ra and 227Ac: grand-daughter nuclides in the 238U and 235U decay chains respectively. The 230Th- 234U, 226Ra- 238U, 231Pa- 235U, and 227Ac- 235U radiochronometers were used to calculate model ages for CRM-U100 standard reference material and two highly-enriched pieces of uranium metal from the International Technical Working Group Round Robin 3 Exercise. In conclusion, the results demonstrate the accuracy of the 226Ra- 238U and 227Ac- 235U chronometers and provide informationmore » about nuclide migration during uranium processing.« less

Dislocation nucleation facilitated by atomic segregation

DOE PAGES

Zou, Lianfeng; Yang, Chaoming; Lei, Yinkai; ...

2017-11-27

Surface segregation—the enrichment of one element at the surface, relative to the bulk—is ubiquitous to multi-component materials. Using the example of a Cu–Au solid solution, we demonstrate that compositional variations induced by surface segregation are accompanied by misfit strain and the formation of dislocations in the subsurface region via a surface di˙usion and trapping process. The resulting chemically ordered surface regions acts as an e˙ective barrier that inhibits subsequent dislocation annihilation at free surfaces. Using dynamic, atomic-scale resolution electron microscopy observations and theory modelling, we show that the dislocations are highly active, and we delineate the specific atomic-scale mechanisms associatedmore » with their nucleation, glide, climb, and annihilation at elevated temperatures. As a result, these observations provide mechanistic detail of how dislocations nucleate and migrate at heterointerfaces in dissimilar-material systems.« less

Tracking of Nuclear Production using Indigenous Species: Final LDRD Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alam, Todd Michael; Alam, Mary Kathleen; McIntyre, Sarah K.

Our LDRD research project sought to develop an analytical method for detection of chemicals used in nuclear materials processing. Our approach is distinctly different than current research involving hardware-based sensors. By utilizing the response of indigenous species of plants and/or animals surrounding (or within) a nuclear processing facility, we propose tracking 'suspicious molecules' relevant to nuclear materials processing. As proof of concept, we have examined TBP, tributylphosphate, used in uranium enrichment as well as plutonium extraction from spent nuclear fuels. We will compare TBP to the TPP (triphenylphosphate) analog to determine the uniqueness of the metabonomic response. We show thatmore » there is a unique metabonomic response within our animal model to TBP. The TBP signature can further be delineated from that of TPP. We have also developed unique methods of instrumental transfer for metabonomic data sets.« less

Developing 226Ra and 227Ac age-dating techniques for nuclear forensics to gain insight from concordant and non-concordant radiochronometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kayzar, Theresa M.; Williams, Ross W.

The model age or ‘date of purification’ of a nuclear material is an important nuclear forensic signature. In this study, chemical separation and MC-ICP-MS measurement techniques were developed for 226 Ra and 227Ac: grand-daughter nuclides in the 238U and 235U decay chains respectively. The 230Th- 234U, 226Ra- 238U, 231Pa- 235U, and 227Ac- 235U radiochronometers were used to calculate model ages for CRM-U100 standard reference material and two highly-enriched pieces of uranium metal from the International Technical Working Group Round Robin 3 Exercise. In conclusion, the results demonstrate the accuracy of the 226Ra- 238U and 227Ac- 235U chronometers and provide informationmore » about nuclide migration during uranium processing.« less

HST spectroscopy of chemically peculiar hot subdwarfs: PG 0909+276 and UVO0512-08

NASA Astrophysics Data System (ADS)

Wild, James; Jeffery, Christopher Simon

2017-12-01

High-resolution ultraviolet spectroscopy of two chemically peculiar hot subdwarfs, PG 0909+276 and UVO0512-08, has been obtained using the Hubble Space Telescope. Chemical abundances in the stars' atmospheres were measured from previous optical spectra and from the new ultraviolet observations. Iron-group metals, including cobalt, copper and zinc, are highly enriched relative to typical subdwarf B (sdB) stars. Lead is also enriched, but with an abundance similar to other sdB stars. The surface chemistry of these two stars is quite distinct from both hydrogen-rich normal sdB stars and also from the intermediate helium-rich sdB stars which show heavy-element superabundances. A full explanation for exotic chemistries in hot subdwarfs remains elusive.

Succinic acid production on xylose-enriched biorefinery streams by Actinobacillus succinogenes in batch fermentation

DOE PAGES

Salvachua, Davinia; Mohagheghi, Ali; Smith, Holly; ...

2016-02-02

Co-production of chemicals from lignocellulosic biomass alongside fuels holds promise for improving the economic outlook of integrated biorefineries. In current biochemical conversion processes that use thermochemical pretreatment and enzymatic hydrolysis, fractionation of hemicellulose-derived and cellulose-derived sugar streams is possible using hydrothermal or dilute acid pretreatment (DAP), which then offers a route to parallel trains for fuel and chemical production from xylose- and glucose-enriched streams. Succinic acid (SA) is a co-product of particular interest in biorefineries because it could potentially displace petroleum-derived chemicals and polymer precursors for myriad applications. Furthermore, SA production from biomass-derived hydrolysates has not yet been fully exploredmore » or developed.« less

[Comparison of essential oil enriched with ultrafiltration method and extraction method respectively from essential oil-in-water emulsion of Citri Reticulatae Pericarpium Viride by GC-MS].

PubMed

Yin, Ailing; Han, Zhifeng; Shen, Jie; Guo, Liwei; Cao, Guiping

2011-10-01

To study on the separation from essential oil-in-water emulsion of Citri Reticulatae Pericarpium Viride by ultrafiltration and acetoacetate extraction methods respectively, and the comparison of the oil yields and chemical compositions. Essential oil-in-water emulsion of Citri Reticulatae Pericarpium Viride was separated by ultrafiltration and acetoacetate extraction methods respectively, and the chemical compositions were analyzed and compared by GC-MS. Ultrafiltration method could enrich essential oil more and its chemical compositions were more similar to the essential oil prepared by steam distillation method. Ultrafiltration method is a good medium to separate essential oil from essential oil-in-water emulsion of Citri Reticulatae Pericarpium Viride.

Magnetic properties of the Bled El Hadba phosphate-bearing formation (Djebel Onk, Algeria): Consequences of the enrichment of the phosphate ore deposit

NASA Astrophysics Data System (ADS)

Bezzi, Nacer; Aïfa, Tahar; Merabet, Djoudi; Pivan, Jean-Yves

2008-02-01

To improve the enrichment of the Thanetian marine phosphate ore deposit from the quarry of Bled El Hadba (Djebel Onk, Algeria) before its exploitation, we first conducted a joint study using different techniques for comparison. These studies reveal that magnetic minerals play a significant role within the matrix of the central productive unit which is squeezed between two other units. Magnetic separation procedures show that there are some positive correlations between magnetic susceptibility and grain size fraction (80-250 μm). These dolomite-rich fractions are more clearly separated. Different tools were used to characterize the magnetic minerals (X-ray, microprobe, differential scanning calorimetry, thermogravimetric and thermomagnetic analyses). They show correlations between magnetic phases and the presence of associated magnetic minerals within the matrix or included in the phosphate ore deposit. They enabled us to distinguish a series of magnetic minerals (magnetite, hematite, maghemite, goethite, ilmenite, pyrite, iron-titanium oxide and titanium oxide sulphate) and to determine that Fe and Ti are prevalent in the separated fractions, following the same variation as Mg. The phosphorous (phosphate) rate is higher in the non-magnetic material, especially in the layers that are rich in dolomitic carbonates (upper and lower units), which could be trapped within the dolomitic matrix, while Magnesium (dolomite) is more important in the magnetic fraction. The separation of phosphate elements and dolomite carbonates is effective and therefore the ore can be enriched through magnetic procedures. Comparison between products enriched by magnetic separation, flotation and calcination showed important differences, chemically, economically and technically speaking.

Impact of Environmental Enrichment Devices on NTP In Vivo Studies

PubMed Central

Churchill, Sheba R.; Morgan, Daniel L.; Kissling, Grace E.; Travlos, Gregory S.; King-Herbert, Angela P.

2015-01-01

The goal of this study was to determine whether the use of nesting material or polycarbonate shelters, as enrichment devices would have an impact on endpoints commonly measured during the conduct of the National Toxicology Program (NTP) 13-week studies. The study design was consistent with the NTP 13-week toxicity studies. Harlan Sprague Dawley (HSD) rats and their offspring, and B6C3F1/N mice were assigned to control (unenriched) and enriched experimental groups. Body weight, food and water consumption, behavioral observations, fecal content, clinical pathology, gross pathology, organ weights, and histopathology were evaluated. Enriched male mice and male and female rats exhibited decreased feed intake without a subsequent decrease in body weight; this may have been the result of the nesting material reducing the effect of cold stress thereby allowing for more efficient use of feed. There were statistical differences in some hematological parameters, however these were not considered physiologically relevant since all values were within the normal range. Gross pathology and histopathological findings were background changes and were not considered enrichment-related. Nesting material and shelters were used frequently and consistently and allowed animals to display species typical behavior. There was no significant impact on commonly measured endpoints in HSD rats and B6C3F1/N mice given enrichment devices. PMID:26873679

Nominations for the 2017 NNSA Pollution Prevention Awards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salzman, Sonja L.; Ballesteros Rodriguez, Sonia; Lopez, Lorraine Bonds

In the field of nuclear forensics, one of the biggest challenges is to dissolve postdetonation debris for analysis. Debris generated after a nuclear detonation is a glassy material that is difficult to dissolve with chemicals. Traditionally, concentrated nitric acid, hydrofluoric acid, or sulfuric acid are employed during the dissolution. These acids, due to their corrosive nature, are not suitable for in-field/on-site sample preparations. Uranium oxides are commonly present in nuclear fuel processing plants and nuclear research facilities. In uranium oxides, the level of uranium isotope enrichment is a sensitive indicator for nuclear nonproliferation and is monitored closely by the Internationalmore » Atomic Energy Agency (IAEA) to ensure there is no misuse of nuclear material or technology for nuclear weapons. During an IAEA on-site inspection at a facility, environmental surface swipe samples are collected and transported to the IAEA headquarters or network of analytical laboratories for further processing. Uranium oxide particles collected on the swipe medium are typically dissolved with inorganic acids and are then analyzed for uranium isotopic compositions. To improve the responsiveness of on-site inspections, in-field detection techniques have been recently explored. However, in-field analysis is bottlenecked by time-consuming and hazardous dissolution procedures, as corrosive inorganic acids must be used. Corrosive chemicals are difficult to use in the field due to personnel safety considerations, and the transportation of such chemicals is highly regulated. It was therefore necessary to develop fast uranium oxide dissolution methods using less hazardous chemicals in support of the rapid infield detection of anomalies in declared nuclear processes.« less

Molten salt synthesis of nitrogen and oxygen enriched hierarchically porous carbons derived from biomass via rapid microwave carbonization for high voltage supercapacitors

NASA Astrophysics Data System (ADS)

Cheng, Yinfeng; Li, Baoqiang; Huang, Yanjuan; Wang, Yaming; Chen, Junchen; Wei, Daqing; Feng, Yujie; Jia, Dechang; Zhou, Yu

2018-05-01

Nitrogen and oxygen enriched hierarchically porous carbons (NOHPCs) derived from biomass have been successfully prepared by rapid microwave carbonization coupled with molten salt synthesis method in only 4 min. ZnCl2 plays important roles as microwave absorber, chemical activation agent and porogen in this process. NOHPC-1:10 sample possesses the maximum specific surface area of 1899 m2 g-1 with a pore volume of 1.16 cm3 g-1 and mesopore ratio of 70%, as well as nitrogen content of 5.30 wt% and oxygen content of 14.12 wt%. When evaluated as an electrode in a three-electrode system with 6 M KOH electrolyte, the material exhibits a high specific capacitance of 276 F g-1 at 0.2 A g-1, with a good rate capability of 90.9% retention at 10 A g-1. More importantly, the symmetric supercapacitor based on NOHPC-1:10 in 1 M Na2SO4 electrolyte exhibits a high energy density of 13.9 Wh kg-1 at a power density of 120 W kg-1 in a wide voltage window of 0-1.6 V, an excellent cycling stability with 95% of capacitance retention after 10,000 cycles. Our strategy provides a facile and rapid way for the preparation of advanced carbon materials derived from biomass towards energy storage applications.

Sulfur amino acids and alanine on pyrite (100) by X-ray photoemission spectroscopy: Surface or molecular role?

NASA Astrophysics Data System (ADS)

Sanchez-Arenillas, M.; Galvez-Martinez, S.; Mateo-Marti, E.

2017-08-01

This paper describes the first successful adsorption of the cysteine, cystine, methionine and alanine amino acids on the pyrite (100) surface under ultra-high vacuum conditions with crucial chemical adsorption parameters driving the process. We have demonstrated by X-ray photoemission spectroscopy (XPS) that the surface pretreatment annealing process on pyrite surfaces is a critical parameter driving surface reactivity. The presence of enriched monosulfide species on the pyrite (100) surface favours the amino acid NH2 chemical form, whereas a longer annealing surface pretreatment of over 3 h repairs the sulfur vacancies in the pyrite, enriching disulfide species on the pyrite surface, which promotes NH3+ adsorption due to the sulfur vacancies in the pyrite being replaced by sulfur atom dimers (S22-) on the surface. Furthermore, even if the surface chemistry (monosulfide or disulfide species enrichment) is the main factor promoting a partial conversion from NH2 to NH3+ species, the unique chemical structure of each amino acid provides a particular fingerprint in the process.

Chemical and organoleptic characteristics of tomato purée enriched with lyophilized tomato pomace.

PubMed

Previtera, Lucio; Fucci, Gabriella; De Marco, Anna; Romanucci, Valeria; Di Fabio, Giovanni; Zarrelli, Armando

2016-04-01

Epidemiological studies have proved that tomato consumption is associated with a lower risk of developing several diseases (for example, certain types of cancers, cardiovascular diseases, macular degeneration, age-related eye disease). Many micronutrients and bioactive compounds are mainly present in peel and seeds and are lost during the processing into sauce, purée, paste and juice. The addition of lyophilized and powdered tomato pomace enhances the properties of purée. In this paper we report the chemical and physicochemical characterization of a purée enriched with 2% dry pomace. Comparison of the analytical data of starting purée with the enriched purée showed a significant increase of all micronutrients, without the taste and appearance being compromised or altered negatively. The product obtained is an example of a functional food rich in health-promoting phytochemicals, with the significant aspect of recovering a waste fraction of the tomato processing that would normally be disposed of in landfill, with associated costs and environmental impact. © 2015 Society of Chemical Industry.

Optimizing the separation performance of a gas centrifuge

NASA Astrophysics Data System (ADS)

Wood, H. G.

1997-11-01

Gas centrifuges were originally developed for the enrichment of U^235 from naturally occurring uranium for the purpose of providing fuel for nuclear power reactors and material for nuclear weapons. This required the separation of a binary mixture composed of U^235 and U^238. Since the end of the cold war, a surplus of enriched uranium exists on the world market, but many centrifuge plants exist in numerous countries. These circumstances together with the growing demand for stable isotopes for chemical and physical research and in medical science has led to the exploration of alternate applications of gas centrifuge technology. In order to acieve these multi-component separations, existing centrifuges must be modified or new centrifuges must be designed. In either case, it is important to have models of the internal flow fields to predict the separation performance and algorithms to seek the optimal operating conditions of the centrifuges. Here, we use the Onsager pancake model of the internal flow field, and we present an optimization strategy which exploits a similarity parameter in the pancake model. Numerical examples will be presented.

A study on the relationships between corrosion properties and chemistry of thermally oxidised surface films formed on polished commercial magnesium alloys AZ31 and AZ61

NASA Astrophysics Data System (ADS)

Feliu, Sebastián; Samaniego, Alejandro; Barranco, Violeta; El-Hadad, A. A.; Llorente, Irene; Serra, Carmen; Galván, J. C.

2014-03-01

This paper studies the changes in chemical composition of the thin oxide surface films induced by heating in air at 200 °C for time intervals from 5 min to 60 min on the freshly polished commercial AZ31 and AZ61 alloys with a view to better understanding their protective properties. This thermal treatment resulted in the formation of layers enriched in metallic aluminium at the interface between the outer MgO surface films and the bulk material. A strong link was found between the degree of metallic Al enrichment in the subsurface layer (from 10 to 15 at.%) observed by XPS (X-ray photoelectron spectroscopy) in the AZ61 treated samples and the increase in protective properties observed by EIS (electrochemical impedance spectroscopy) in the immersion test in 0.6 M NaCl. Heating for 5-60 min in air at 200 °C seems to be an effective, easy to perform and inexpensive method for increasing the corrosion resistance of the AZ61 alloy by approximately two or three times.

Siderophile element constraints on the origin of the Moon

PubMed Central

Walker, Richard J.

2014-01-01

Discovery of small enrichments in 182W/184W in some Archaean rocks, relative to modern mantle, suggests both exogeneous and endogenous modifications to highly siderophile element (HSE) and moderately siderophile element abundances in the terrestrial mantle. Collectively, these isotopic enrichments suggest the formation of chemically fractionated reservoirs in the terrestrial mantle that survived the putative Moon-forming giant impact, and also provide support for the late accretion hypothesis. The lunar mantle sources of volcanic glasses and basalts were depleted in HSEs relative to the terrestrial mantle by at least a factor of 20. The most likely explanations for the disparity between the Earth and Moon are either that the Moon received a disproportionately lower share of late accreted materials than the Earth, such as may have resulted from stochastic late accretion, or the major phase of late accretion occurred prior to the Moon-forming event, and the putative giant impact led to little drawdown of HSEs to the Earth's core. High precision determination of the 182W isotopic composition of the Moon can help to resolve this issue. PMID:25114313

Isolation of n-decyl-alpha(1-->6) isomaltoside from a technical APG mixture and its identification by the parallel use of LC-MS and NMR spectroscopy

PubMed

Billian; Hock; Doetzer; Stan; Dreher

2000-10-15

The identification of n-decyl alpha(1-->6)isomaltoside as a main component of technical alkyl polyglucoside (APG) mixtures by the parallel use of liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy is described. Following enrichment on a styrene-divinylbenzene-based solid-phase extraction material, unknown components were separated by reversed-phase liquid chromatography (LC). Chemical characterization was achieved by both mass spectrometry and NMR spectroscopy. It is demonstrated that the combination of LC-MS with various NMR techniques is very suitable for stereochemical assignment of unknown components in technical APG mixtures.

DNA-Encoded Dynamic Combinatorial Chemical Libraries.

PubMed

Reddavide, Francesco V; Lin, Weilin; Lehnert, Sarah; Zhang, Yixin

2015-06-26

Dynamic combinatorial chemistry (DCC) explores the thermodynamic equilibrium of reversible reactions. Its application in the discovery of protein binders is largely limited by difficulties in the analysis of complex reaction mixtures. DNA-encoded chemical library (DECL) technology allows the selection of binders from a mixture of up to billions of different compounds; however, experimental results often show low a signal-to-noise ratio and poor correlation between enrichment factor and binding affinity. Herein we describe the design and application of DNA-encoded dynamic combinatorial chemical libraries (EDCCLs). Our experiments have shown that the EDCCL approach can be used not only to convert monovalent binders into high-affinity bivalent binders, but also to cause remarkably enhanced enrichment of potent bivalent binders by driving their in situ synthesis. We also demonstrate the application of EDCCLs in DNA-templated chemical reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A uniform contribution of core-collapse and type Ia supernovae to the chemical enrichment pattern in the outskirts of the Virgo Cluster

DOE PAGES

Simionescu, A.; Werner, N.; Urban, O.; ...

2015-09-24

We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 r 200). Chemical enrichment of the intergalactic medium due solely to core-collapse supernovae (SNcc) is excluded with very high significance; instead, the measuredmore » metal abundance ratios are generally consistent with the solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and SNe Ia contributing to the metal budget during the period of peak star formation activity at redshifts of 2–3. Furthermore, we estimate the ratio between the number of SNe Ia and the total number of supernovae enriching the intergalactic medium to be between 12% and 37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SN Ia contribution estimated for the cluster cores.« less

Descendants of the first stars: the distinct chemical signature of second generation stars

NASA Astrophysics Data System (ADS)

Hartwig, Tilman; Yoshida, Naoki; Magg, Mattis; Frebel, Anna; Glover, Simon C. O.; Gómez, Facundo A.; Griffen, Brendan; Ishigaki, Miho N.; Ji, Alexander P.; Klessen, Ralf S.; O'Shea, Brian W.; Tominaga, Nozomu

2018-05-01

Extremely metal-poor (EMP) stars in the Milky Way (MW) allow us to infer the properties of their progenitors by comparing their chemical composition to the metal yields of the first supernovae. This method is most powerful when applied to mono-enriched stars, i.e. stars that formed from gas that was enriched by only one previous supernova. We present a novel diagnostic to identify this subclass of EMP stars. We model the first generations of star formation semi-analytically, based on dark matter halo merger trees that yield MW-like halos at the present day. Radiative and chemical feedback are included self-consistently and we trace all elements up to zinc. Mono-enriched stars account for only ˜1% of second generation stars in our fiducial model and we provide an analytical formula for this probability. We also present a novel analytical diagnostic to identify mono-enriched stars, based on the metal yields of the first supernovae. This new diagnostic allows us to derive our main results independently from the specific assumptions made regarding Pop III star formation, and we apply it to a set of observed EMP stars to demonstrate its strengths and limitations. Our results may provide selection criteria for current and future surveys and therefore contribute to a deeper understanding of EMP stars and their progenitors.

A UNIFORM CONTRIBUTION OF CORE-COLLAPSE AND TYPE Ia SUPERNOVAE TO THE CHEMICAL ENRICHMENT PATTERN IN THE OUTSKIRTS OF THE VIRGO CLUSTER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simionescu, A.; Ichinohe, Y.; Werner, N.

2015-10-01

We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 r{sub 200}). Chemical enrichment of the intergalactic medium due solely to core-collapse supernovae (SNcc) is excluded with very high significance; instead, the measuredmore » metal abundance ratios are generally consistent with the solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and SNe Ia contributing to the metal budget during the period of peak star formation activity at redshifts of 2–3. We estimate the ratio between the number of SNe Ia and the total number of supernovae enriching the intergalactic medium to be between 12% and 37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SN Ia contribution estimated for the cluster cores.« less

Robust, Sensitive, and Automated Phosphopeptide Enrichment Optimized for Low Sample Amounts Applied to Primary Hippocampal Neurons.

PubMed

Post, Harm; Penning, Renske; Fitzpatrick, Martin A; Garrigues, Luc B; Wu, W; MacGillavry, Harold D; Hoogenraad, Casper C; Heck, Albert J R; Altelaar, A F Maarten

2017-02-03

Because of the low stoichiometry of protein phosphorylation, targeted enrichment prior to LC-MS/MS analysis is still essential. The trend in phosphoproteome analysis is shifting toward an increasing number of biological replicates per experiment, ideally starting from very low sample amounts, placing new demands on enrichment protocols to make them less labor-intensive, more sensitive, and less prone to variability. Here we assessed an automated enrichment protocol using Fe(III)-IMAC cartridges on an AssayMAP Bravo platform to meet these demands. The automated Fe(III)-IMAC-based enrichment workflow proved to be more effective when compared to a TiO 2 -based enrichment using the same platform and a manual Ti(IV)-IMAC-based enrichment workflow. As initial samples, a dilution series of both human HeLa cell and primary rat hippocampal neuron lysates was used, going down to 0.1 μg of peptide starting material. The optimized workflow proved to be efficient, sensitive, and reproducible, identifying, localizing, and quantifying thousands of phosphosites from just micrograms of starting material. To further test the automated workflow in genuine biological applications, we monitored EGF-induced signaling in hippocampal neurons, starting with only 200 000 primary cells, resulting in ∼50 μg of protein material. This revealed a comprehensive phosphoproteome, showing regulation of multiple members of the MAPK pathway and reduced phosphorylation status of two glutamate receptors involved in synaptic plasticity.

Bioanalytical assessment of adaptive stress responses in drinking water: A predictive tool to differentiate between micropollutants and disinfection by-products.

PubMed

Hebert, Armelle; Feliers, Cedric; Lecarpentier, Caroline; Neale, Peta A; Schlichting, Rita; Thibert, Sylvie; Escher, Beate I

2018-04-01

Drinking water can contain low levels of micropollutants, as well as disinfection by-products (DBPs) that form from the reaction of disinfectants with organic and inorganic matter in water. Due to the complex mixture of trace chemicals in drinking water, targeted chemical analysis alone is not sufficient for monitoring. The current study aimed to apply in vitro bioassays indicative of adaptive stress responses to monitor the toxicological profiles and the formation of DBPs in three drinking water distribution systems in France. Bioanalysis was complemented with chemical analysis of forty DBPs. All water samples were active in the oxidative stress response assay, but only after considerable sample enrichment. As both micropollutants in source water and DBPs formed during treatment can contribute to the effect, the bioanalytical equivalent concentration (BEQ) approach was applied for the first time to determine the contribution of DBPs, with DBPs found to contribute between 17 and 58% of the oxidative stress response. Further, the BEQ approach was also used to assess the contribution of volatile DBPs to the observed effect, with detected volatile DBPs found to have only a minor contribution as compared to the measured effects of the non-volatile chemicals enriched by solid-phase extraction. The observed effects in the distribution systems were below any level of concern, quantifiable only at high enrichment and not different from bottled mineral water. Integrating bioanalytical tools and the BEQ mixture model for monitoring drinking water quality is an additional assurance that chemical monitoring is not overlooking any unknown chemicals or transformation products and can help to ensure chemically safe drinking water. Copyright © 2017. Published by Elsevier Ltd.

Institutional, Material and Economic Constraints in Languages Education: Unequal Provision of Linguistic Resources in Early Childhood and Primary Settings in Australia

ERIC Educational Resources Information Center

Jones Díaz, Criss

2014-01-01

In Australia, languages education in early childhood and primary education includes three main approaches: transitional, enrichment and full bilingual programmes. This article proposes that transitional and enrichment programmes in Australia are constituted and shaped by competing and contested institutional, material, discursive and economic…

Global Analysis Reveals Families of Chemical Motifs Enriched for hERG Inhibitors

PubMed Central

Du, Fang; Babcock, Joseph J.; Yu, Haibo; Zou, Beiyan; Li, Min

2015-01-01

Promiscuous inhibition of the human ether-à-go-go-related gene (hERG) potassium channel by drugs poses a major risk for life threatening arrhythmia and costly drug withdrawals. Current knowledge of this phenomenon is derived from a limited number of known drugs and tool compounds. However, in a diverse, naïve chemical library, it remains unclear which and to what degree chemical motifs or scaffolds might be enriched for hERG inhibition. Here we report electrophysiology measurements of hERG inhibition and computational analyses of >300,000 diverse small molecules. We identify chemical ‘communities’ with high hERG liability, containing both canonical scaffolds and structurally distinctive molecules. These data enable the development of more effective classifiers to computationally assess hERG risk. The resultant predictive models now accurately classify naïve compound libraries for tendency of hERG inhibition. Together these results provide a more complete reference map of characteristic chemical motifs for hERG liability and advance a systematic approach to rank chemical collections for cardiotoxicity risk. PMID:25700001

13C cell wall enrichment and ionic liquid NMR analysis: progress towards a high-throughput detailed chemical analysis of the whole plant cell wall.

PubMed

Foston, Marcus; Samuel, Reichel; Ragauskas, Arthur J

2012-09-07

The ability to accurately and rapidly measure plant cell wall composition, relative monolignol content and lignin-hemicellulose inter-unit linkage distributions has become essential to efforts centered on reducing the recalcitrance of biomass by genetic engineering. Growing (13)C enriched transgenic plants is a viable route to achieve the high-throughput, detailed chemical analysis of whole plant cell wall before and after pretreatment and microbial or enzymatic utilization by (13)C nuclear magnetic resonance (NMR) in a perdeuterated ionic liquid solvent system not requiring component isolation. 1D (13)C whole cell wall ionic liquid NMR of natural abundant and (13)C enriched corn stover stem samples suggest that a high level of uniform labeling (>97%) can significantly reduce the total NMR experiment times up to ~220 times. Similarly, significant reduction in total NMR experiment time (~39 times) of the (13)C enriched corn stover stem samples for 2D (13)C-(1)H heteronuclear single quantum coherence NMR was found.

Improving the lipid profile of ready-to-cook meat products by addition of omega-3 microcapsules: effect on oxidation and sensory analysis.

PubMed

Pérez-Palacios, Trinidad; Ruiz-Carrascal, Jorge; Jiménez-Martín, Estefanía; Solomando, Juan Carlos; Antequera, Teresa

2018-04-15

The omega-3 enrichment of ready-to-cook meat products by microencapsulated fish oil (MFO) addition was analyzed. Accordingly, three batches of chicken nuggets were prepared: (i) control (C); (ii) enriched in bulk fish oil (BFO); and (iii) with added MFO. Sensory features, acceptability, oxidative stability and volatile compounds were analyzed. MFO nuggets did not differ from C ones with respect to any sensory trait. BFO showed increased juiciness and saltiness but decreased meat flavor. Acceptability was not affected by enrichment. Consumers were not able to differentiate between C and MFO in a triangle test, although they could clearly identify BFO nuggets. Higher levels of lipid and protein oxidation indicators and of volatile compounds from fatty acid oxidation were found in BFO nuggets compared to C and MFO nuggets. Enrichment of ready-to-cook meat products in omega-3 fatty acids with MFO provides both lipid and protein oxidative protection without changes in sensory quality. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Searching for self-enrichment in Cygnus OB2

NASA Astrophysics Data System (ADS)

Berlanas, Sara R.; Herrero, Artemio; Comerón, Fernando; Pasquali, Anna; Simón-Díaz, Sergio

2017-11-01

Cygnus OB2 is a rich and relatively close (d~1.4 kpc) OB association in our Galaxy. It represents an ideal testbed for our theories about self-enrichment processes produced by pollution of the interstellar medium by successive generations of massive stars. Comerón & Pasquali (2012, A&A, 543, A101) found a correlation between the age of young stellar groups in Cygnus OB2 and their Galactic longitude. If is associated with a chemical composition gradient, it could support these self-enrichment processes.

Characterizing the Chemistry of the Milky Way Stellar Halo: Detailed Chemical Analysis of a Metal-poor Stellar Stream

NASA Astrophysics Data System (ADS)

Roederer, Ian U.; Sneden, Christopher; Thompson, Ian B.; Preston, George W.; Shectman, Stephen A.

2010-03-01

We present the results of a detailed abundance analysis of one of the confirmed building blocks of the Milky Way stellar halo, a kinematically coherent metal-poor stellar stream. We have obtained high-resolution and high signal-to-noise spectra of 12 probable stream members using the Magellan Inamori Kyocera Echelle spectrograph on the Magellan-Clay Telescope at Las Campanas Observatory and the 2dCoude spectrograph on the Smith Telescope at McDonald Observatory. We have derived abundances or upper limits for 51 species of 46 elements in each of these stars. The stream members show a range of metallicity (-3.4 < [Fe/H] <-1.5) but are otherwise chemically homogeneous, with the same star-to-star dispersion in [X/Fe] as the rest of the halo. This implies that, in principle, a significant fraction of the Milky Way stellar halo could have formed from accreted systems like the stream. The stream stars show minimal evolution in the α or Fe-group elements over the range of metallicity. This stream is enriched with material produced by the main and weak components of the rapid neutron-capture process and shows no evidence for enrichment by the slow neutron-capture process. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. This paper includes data taken at The McDonald Observatory of the University of Texas at Austin.

78 FR 23312 - Uranium Enrichment Fuel Cycle Inspection Reports Regarding Louisiana Energy Services, National...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-18

... NUCLEAR REGULATORY COMMISSION [Docket No. 70-3103; NRC-2010-0264] Uranium Enrichment Fuel Cycle Inspection Reports Regarding Louisiana Energy Services, National Enrichment Facility, Eunice, New Mexico..., Division of Fuel Cycle Safety, and Safeguards Office of Nuclear Material Safety, and Safeguards. [FR Doc...

Effect of selenium-enriched organic material amendment on selenium fraction transformation and bioavailability in soil.

PubMed

Wang, Dan; Dinh, Quang Toan; Anh Thu, Tran Thi; Zhou, Fei; Yang, Wenxiao; Wang, Mengke; Song, Weiwei; Liang, Dongli

2018-05-01

To exploit the plant byproducts from selenium (Se) biofortification and reduce environmental risk of inorganic Se fertilizer, pot experiment was conducted in this study. The effects of Se-enriched wheat (Triticum aestivum L.) straw (WS + Se) and pak choi (Brassica chinensis L.) (P + Se) amendment on organo-selenium speciation transformation in soil and its bioavailability was evaluated by pak choi uptake. The Se contents of the cultivated pak choi in treatments amended with the same amount of Se-enriched wheat straw and pak choi were 1.7 and 9.7 times in the shoots and 2.3 and 6.3 times in the roots compared with control treatment. Soil respiration rate was significantly increased after all organic material amendment in soil (p < 0.05), which accelerated the mineralization of organic materials and thus resulted in soluble Se (SOL-Se), exchangeable Se (EX-Se), and fulvic acid-bound Se (FA-Se) fraction increasing by 25.2-29.2%, 9-13.8%, and 4.92-8.28%, respectively. In addition, both Pearson correlation and cluster analysis showed that EX-Se and FA-Se were better indicators for soil Se availability in organic material amendment soils. The Marquardt-Levenberg Model well described the dynamic kinetics of FA-Se content after Se-enriched organic material amendment in soil mainly because of the mineralization of organic carbon and organo-selenium. The utilization of Se in P + Se treatment was significantly higher than those in WS + Se treatment because of the different mineralization rates and the amount of FA-Se in soil. Se-enriched organic materials amendment can not only increase the availability of selenium in soil but also avoid the waste of valuable Se source. Copyright © 2018 Elsevier Ltd. All rights reserved.

Conjunctive and mineralization impact of municipal solid waste compost and inorganic fertilizer on lysimeter and pot studies.

PubMed

Khalid, Iqbal; Nadeem, Amana; Ahmed, Rauf; Husnain, Anwer

2014-01-01

Objectives of the present study were to investigate the physico-chemical properties of municipal solid waste (MSW)-enriched compost and its effect on nutrient mineralization and subsequent plant growth. The enrichment of MSW compost by inorganic salts enhanced the humification rate and reduced the carbon nitrogen (C/N) ratio in less time than control compost. The chemical properties of compost, C/N ratio, humic acid, fulvic acid, degree of polymerization and humification index revealed the significant correlation amid properties. A laboratory-scale experiment evaluated the conjunctive effect of MSW compost and inorganic fertilizer on tomato plants in a pot experiment. In the pot experiment five treatments, Inorganic fertilizer (T1), enriched compost (T2), enriched compost 80% + 20% inorganic fertilizer (T3), enriched compost 60% + 40% inorganic fertilizer (T4) were defined including control (Ts), applied at the rate of 110 kg-N/ha and results revealed that all treatments significantly enhanced horticultural production of tomato plant; however T4 was most effectual as compared with control, T1, T2 and T3. Augmentation in organic matter and available phosphorus (P) potassium (K) and nitrogen (N) were also observed in compost treatments. The leachability and phytoavailability of phosphorus (P), potassium (K) and nitrogen (N) from sandy soil, amended with enriched, control compost and inorganic fertilizer at rates of 200, 400 and 600 kg-N/ha were evaluated in a lysimeter study. Results illustrated that concentration of mineral nitrogen was elevated in the leachate of inorganic fertilizer than enriched and control composts; therefore compost fortifies soil with utmost nutrients for plants' growth.

Metabolomic analysis can detect the composition of pasta enriched with fibre after cooking.

PubMed

Beleggia, Romina; Menga, Valeria; Platani, Cristiano; Nigro, Franca; Fragasso, Mariagiovanna; Fares, Clara

2016-07-01

Several studies have demonstrated that metabolomics has a definite place in food quality, nutritional value, and safety issues. The aim of the present study was to determine and compare the metabolites in different pasta samples with fibre, and to investigate the modifications induced in these different kinds of pasta during cooking, using a gas chromatography-mass spectrometry-based metabolomics approach. Differences were seen for some of the amino acids, which were absent in control pasta, while were present both in the commercially available high-fibre pasta (samples A-C) and the enriched pasta (samples D-F). The highest content in reducing sugars was observed in enriched samples in comparison with high-fibre pasta. The presence of stigmasterol in samples enriched with wheat bran was relevant. Cooking decreased all of the metabolites: the high-fibre pasta (A-C) and Control showed losses of amino acids and tocopherols, while for sugars and organic acids, the decrease depended on the pasta sample. The enriched pasta samples (D-F) showed the same decreases with the exception of phytosterols, and in pasta with barley the decrease of saturated fatty acids was not significant as for tocopherols in pasta with oat. Principal component analysis of the metabolites and the pasta discrimination was effective in differentiating the enriched pasta from the commercial pasta, both uncooked and cooked. The study has established that such metabolomic analyses provide useful tools in the evaluation of the changes in nutritional compounds in high-fibre and enriched pasta, both before and after cooking. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

HIGHLY ENRICHED URANIUM BLEND DOWN PROGRAM AT THE SAVANNAH RIVER SITE PRESENT AND FUTURE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magoulas, V; Charles Goergen, C; Ronald Oprea, R

2008-06-05

The Department of Energy (DOE) and Tennessee Valley Authority (TVA) entered into an Interagency Agreement to transfer approximately 40 metric tons of highly enriched uranium (HEU) to TVA for conversion to fuel for the Browns Ferry Nuclear Power Plant. Savannah River Site (SRS) inventories included a significant amount of this material, which resulted from processing spent fuel and surplus materials. The HEU is blended with natural uranium (NU) to low enriched uranium (LEU) with a 4.95% 235U isotopic content and shipped as solution to the TVA vendor. The HEU Blend Down Project provided the upgrades needed to achieve the productmore » throughput and purity required and provided loading facilities. The first blending to low enriched uranium (LEU) took place in March 2003 with the initial shipment to the TVA vendor in July 2003. The SRS Shipments have continued on a regular schedule without any major issues for the past 5 years and are due to complete in September 2008. The HEU Blend program is now looking to continue its success by dispositioning an additional approximately 21 MTU of HEU material as part of the SRS Enriched Uranium Disposition Project.« less

Evaluation of the physicochemical properties of gluten-free pasta enriched with resistant starch.

PubMed

Foschia, Martina; Beraldo, Paola; Peressini, Donatella

2017-01-01

The objective was to examine the potential use of resistant starch (RS) as a fibre-enriching ingredient in gluten-free pasta. Pasta was enriched with commercial RS type II (Hi-Maize™ 260) at 100-200 g kg -1 substitution of rice flour. The effects on the rheological properties of dough and pasta quality as a result of RS addition and the loss in RS due to the process were evaluated. Dough water absorption was not influenced by the addition of RS. The cooking loss (CL) of RS-enriched samples was 30% lower than reference without fibre. The addition of RS significantly increased firmness of cooked pasta, and above 100 g kg -1 RS level of substitution samples showed a lower stickiness value. Dynamic rheological tests on pasta dough showed a higher storage modulus for fibre samples, indicating a higher number of elastically physical interactions. Loss in RS in uncooked pasta was about 31% compared with the initial amount added to the product. The addition of RS improved the quality of gluten-free pasta owing to its ability to increase the firmness and decrease the CL and stickiness of cooked pasta. The product enriched with 200 g kg -1 RS can be considered a source of DF. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

3D hierarchical interface-enriched finite element method: Implementation and applications

NASA Astrophysics Data System (ADS)

Soghrati, Soheil; Ahmadian, Hossein

2015-10-01

A hierarchical interface-enriched finite element method (HIFEM) is proposed for the mesh-independent treatment of 3D problems with intricate morphologies. The HIFEM implements a recursive algorithm for creating enrichment functions that capture gradient discontinuities in nonconforming finite elements cut by arbitrary number and configuration of materials interfaces. The method enables the mesh-independent simulation of multiphase problems with materials interfaces that are in close proximity or contact while providing a straightforward general approach for evaluating the enrichments. In this manuscript, we present a detailed discussion on the implementation issues and required computational geometry considerations associated with the HIFEM approximation of thermal and mechanical responses of 3D problems. A convergence study is provided to investigate the accuracy and convergence rate of the HIFEM and compare them with standard FEM benchmark solutions. We will also demonstrate the application of this mesh-independent method for simulating the thermal and mechanical responses of two composite materials systems with complex microstructures.

Characterization of high-purity 82Se-enriched ZnSe for double-beta decay bolometer/scintillation detectors

NASA Astrophysics Data System (ADS)

Silva, B. C.; de Oliveira, R.; Ribeiro, G. M.; Cury, L. A.; Leal, A. S.; Nagorny, S.; Krambrock, K.

2018-02-01

Zinc selenide (ZnSe), when enriched with 82Se isotope, is one of the most promising materials for the construction of a bolometer/scintillation detector to study neutrinoless double beta decay (0νDBD). Because the 0νDBD is a very rare event, a high quantity of high-purity monocrystalline ZnSe is needed, which means high costs. Therefore, the knowledge of the best material parameters, especially the presence of point defects, is essential to make feasible the construction of such a detector. In this work, both the as-grown and thermally annealed ZnSe enriched to 95% with the 82Se isotope grown by the Bridgman technique from high-purity starting materials were characterized by electron paramagnetic resonance (EPR), photo-EPR, neutron activation, photoluminescence, and electrical measurements. It is shown that although thermal annealing increases crystal homogeneity and reduces microcracks, the scintillation efficiency is much better for the as-grown material. The higher scintillation efficiency is due to the presence of donor acceptor pairs in the as-grown material, which are responsible for strong luminescence/scintillation in the red spectral region. By photo-EPR, the donor acceptor pairs are identified as closed VZn - AlZn pairs which are lost during the annealing procedure. Electrical characterization shows that the as-grown material is of good quality as it has high electron mobility at low temperatures. Excellent material parameters for the construction of the bolometer/scintillation detector based on enriched Zn82Se are discussed.

Responsiveness of cats (Felidae) to silver vine (Actinidia polygama), Tatarian honeysuckle (Lonicera tatarica), valerian (Valeriana officinalis) and catnip (Nepeta cataria).

PubMed

Bol, Sebastiaan; Caspers, Jana; Buckingham, Lauren; Anderson-Shelton, Gail Denise; Ridgway, Carrie; Buffington, C A Tony; Schulz, Stefan; Bunnik, Evelien M

2017-03-16

Olfactory stimulation is an often overlooked method of environmental enrichment for cats in captivity. The best known example of olfactory enrichment is the use of catnip, a plant that can cause an apparently euphoric reaction in domestic cats and most of the Pantherinae. It has long been known that some domestic cats and most tigers do not respond to catnip. Although many anecdotes exist of other plants with similar effects, data are lacking about the number of cats that respond to these plants, and if cats that do not respond to catnip respond to any of them. Furthermore, much is still unknown about which chemicals in these plants cause this response. We tested catnip, silver vine, Tatarian honeysuckle and valerian root on 100 domestic cats and observed their response. Each cat was offered all four plant materials and a control, multiple times. Catnip and silver vine also were offered to nine tigers. The plant materials were analyzed by gas chromatography coupled with mass spectrometry to quantify concentrations of compounds believed to exert stimulating effects on cats. Nearly all domestic cats responded positively to olfactory enrichment. In agreement with previous studies, one out of every three cats did not respond to catnip. Almost 80% of the domestic cats responded to silver vine and about 50% to Tatarian honeysuckle and valerian root. Although cats predominantly responded to fruit galls of the silver vine plant, some also responded positively to its wood. Of the cats that did not respond to catnip, almost 75% did respond to silver vine and about one out of three to Tatarian honeysuckle. Unlike domestic cats, tigers were either not interested in silver vine or responded disapprovingly. The amount of nepetalactone was highest in catnip and only present at marginal levels in the other plants. Silver vine contained the highest concentrations of all other compounds tested. Olfactory enrichment for cats may have great potential. Silver vine powder from dried fruit galls and catnip were most popular among domestic cats. Silver vine and Tatarian honeysuckle appear to be good alternatives to catnip for domestic cats that do not respond to catnip.

Method of controlling the mercury vapor pressure in a photo-chemical lamp or vapor filter used for Hg.sup.196 enrichment

DOEpatents

Grossman, Mark W.

1993-01-01

The present invention is directed to a method of eliminating the cold spot zones presently used on Hg.sup.196 isotope separation lamps and filters by the use of a mercury amalgams, preferably mercury - indium amalgams. The use of an amalgam affords optimization of the mercury density in the lamp and filter of a mercury enrichment reactor, particularly multilamp enrichment reactors. Moreover, the use of an amalgam in such lamps and/or filters affords the ability to control the spectral line width of radiation emitted from lamps, a requirement for mercury enrichment.

Method of controlling the mercury vapor pressure in a photo-chemical lamp or vapor filter used for Hg[sup 196] enrichment

DOEpatents

Grossman, M.W.

1993-02-16

The present invention is directed to a method of eliminating the cold spot zones presently used on Hg[sup 196] isotope separation lamps and filters by the use of a mercury amalgams, preferably mercury - indium amalgams. The use of an amalgam affords optimization of the mercury density in the lamp and filter of a mercury enrichment reactor, particularly multilamp enrichment reactors. Moreover, the use of an amalgam in such lamps and/or filters affords the ability to control the spectral line width of radiation emitted from lamps, a requirement for mercury enrichment.

A comparison of the effects of two methods of acclimation of aerobic biodegradability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, H.M.

1993-11-01

The acclimation or adaptation of microorganisms to organic chemicals is an important factor influencing both the rate and the extent of biodegradation. In this study two acclimation procedures were evaluated in terms of their effectiveness in enhancing biodegradation, their relative ease of use in the laboratory, and the implications for biodegradability testing. In the single-flask procedure, microorganisms were acclimated for 2 to 7 d in a single acclimation flask at constant or increasing concentrations of the test chemical without transfer of microorganisms. In the second procedure, the enrichment procedure, microorganisms were acclimated in a series of flasks over a 21-dmore » period by making adaptive transfers to increasing concentrations of the test chemical. Acclimated microorganisms from each procedure were used as the source of inoculum for subsequent biodegradation tests in which carbon dioxide evolution was measured. Six chemicals were tested: quinoline, p-nitrophenol, N-methylaniline, N,N-dimethylaniline, acrylonitrile, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. Microorganisms acclimated in the single-flask procedure were much more effective than those acclimated in the enrichment procedure in degrading the test chemicals. The single-flask procedure is more convenient to use, and it permits monitoring of the time needed for acclimation. The results from these studies have implications for the methodology used in biodegradation test systems and suggest caution before adopting a multiple-flask, enrichment acclimation procedure before the performance of standardized tests for aerobic biodegradability.« less

Sensory, Physico-Chemical and Water Sorption Properties of Corn Extrudates Enriched with Spirulina.

PubMed

Tańska, Małgorzata; Konopka, Iwona; Ruszkowska, Millena

2017-09-01

This study compares the quality of extrudates made from corn grits with the addition of up to 8% of spirulina powder. The sensory properties (shape, color, aroma, taste and crispness), chemicals (content of water, protein, fat, ash, fiber, carbohydrates, carotenoids, chlorophyll and phycocyanin) and physical properties (color, water absorption index, expansion indices, texture and water sorption properties) were determined. It has been found that spirulina-enriched extrudates had slightly lower sensory scores, but the addition of spirulina improved their nutritional value. The contents of protein, ash, fiber and β-carotene increased in extrudates with 8% of spirulina by 34, 36, 140 and 1,260%, respectively. The increasing addition of spirulina caused a decrease in extrudates lightness, an increase in their greenness and yellowness accompanied by a decrease of expansion indices and an increase of softness. Only small differences were found in water sorption properties, suggesting a similar behavior of spirulina-enriched extrudates during storage.

Silicon Isotopic Fractionation of CAI-like Vacuum Evaporation Residues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knight, K; Kita, N; Mendybaev, R

2009-06-18

Calcium-, aluminum-rich inclusions (CAIs) are often enriched in the heavy isotopes of magnesium and silicon relative to bulk solar system materials. It is likely that these isotopic enrichments resulted from evaporative mass loss of magnesium and silicon from early solar system condensates while they were molten during one or more high-temperature reheating events. Quantitative interpretation of these enrichments requires laboratory determinations of the evaporation kinetics and associated isotopic fractionation effects for these elements. The experimental data for the kinetics of evaporation of magnesium and silicon and the evaporative isotopic fractionation of magnesium is reasonably complete for Type B CAI liquidsmore » (Richter et al., 2002, 2007a). However, the isotopic fractionation factor for silicon evaporating from such liquids has not been as extensively studied. Here we report new ion microprobe silicon isotopic measurements of residual glass from partial evaporation of Type B CAI liquids into vacuum. The silicon isotopic fractionation is reported as a kinetic fractionation factor, {alpha}{sub Si}, corresponding to the ratio of the silicon isotopic composition of the evaporation flux to that of the residual silicate liquid. For CAI-like melts, we find that {alpha}{sub Si} = 0.98985 {+-} 0.00044 (2{sigma}) for {sup 29}Si/{sup 28}Si with no resolvable variation with temperature over the temperature range of the experiments, 1600-1900 C. This value is different from what has been reported for evaporation of liquid Mg{sub 2}SiO{sub 4} (Davis et al., 1990) and of a melt with CI chondritic proportions of the major elements (Wang et al., 2001). There appears to be some compositional control on {alpha}{sub Si}, whereas no compositional effects have been reported for {alpha}{sub Mg}. We use the values of {alpha}Si and {alpha}Mg, to calculate the chemical compositions of the unevaporated precursors of a number of isotopically fractionated CAIs from CV chondrites whose chemical compositions and magnesium and silicon isotopic compositions have been previously measured.« less

R-process enrichment from a single event in an ancient dwarf galaxy.

PubMed

Ji, Alexander P; Frebel, Anna; Chiti, Anirudh; Simon, Joshua D

2016-03-31

Elements heavier than zinc are synthesized through the rapid (r) and slow (s) neutron-capture processes. The main site of production of the r-process elements (such as europium) has been debated for nearly 60 years. Initial studies of trends in chemical abundances in old Milky Way halo stars suggested that these elements are produced continually, in sites such as core-collapse supernovae. But evidence from the local Universe favours the idea that r-process production occurs mainly during rare events, such as neutron star mergers. The appearance of a plateau of europium abundance in some dwarf spheroidal galaxies has been suggested as evidence for rare r-process enrichment in the early Universe, but only under the assumption that no gas accretes into those dwarf galaxies; gas accretion favours continual r-process enrichment in these systems. Furthermore, the universal r-process pattern has not been cleanly identified in dwarf spheroidals. The smaller, chemically simpler, and more ancient ultrafaint dwarf galaxies assembled shortly after the first stars formed, and are ideal systems with which to study nucleosynthesis events such as the r-process. Reticulum II is one such galaxy. The abundances of non-neutron-capture elements in this galaxy (and others like it) are similar to those in other old stars. Here, we report that seven of the nine brightest stars in Reticulum II, observed with high-resolution spectroscopy, show strong enhancements in heavy neutron-capture elements, with abundances that follow the universal r-process pattern beyond barium. The enhancement seen in this 'r-process galaxy' is two to three orders of magnitude higher than that detected in any other ultrafaint dwarf galaxy. This implies that a single, rare event produced the r-process material in Reticulum II. The r-process yield and event rate are incompatible with the source being ordinary core-collapse supernovae, but consistent with other possible sources, such as neutron star mergers.

Characterizing cosmochemical materials with genetic affinities to the Earth: Genetic and chronological diversity within the IAB iron meteorite complex

NASA Astrophysics Data System (ADS)

Worsham, Emily A.; Bermingham, Katherine R.; Walker, Richard J.

2017-06-01

The IAB iron meteorite complex consists of a main group (MG) and five chemical subgroups (sLL, sLM, sLH, sHL, and sHH). Here, mass-independent Mo and radiogenic 182W isotope compositions are reported for IAB complex meteorites to evaluate the genetics and chronology, respectively, of the MG and subgroups. Osmium isotopes are used to correct for cosmic ray exposure effects on isotopes of Mo and W. The MG and three subgroups (i.e., sLL, sLM, and sLH), characterized by low Au abundances, have the same Mo isotopic compositions within analytical uncertainty, consistent with a common genetic origin. These meteorites, together with winonaites, are the only cosmochemical materials yet identified with Mo isotopic compositions that are identical to Earth. The Mo isotopic compositions of two subgroups characterized by higher Au abundances (sHL and sHH) are identical to one another within uncertainty, but differ from the low Au subgroups, indicating derivation from genetically distinct materials. The MG has a 182W, post calcium-aluminum inclusion (CAI) formation model age of 3.4 ± 0.7 Ma. One of the low Au subgroups (sLM) is ∼1.7 Ma younger, whereas the high Au subgroups are ∼1.5-3 Ma older. The new Mo-W data, coupled with chemical data, indicate that the MG and the low Au subgroups formed in different impact-generated melts, some of which evidently formed on a chemically disparate, but genetically identical parent body. The high Au subgroups likely formed via core-formation processes on separate, internally-heated parent bodies from other IAB subgroups. The IAB complex meteorites fall on a linear trend defined by 94Mo/96Mo vs. 95Mo/96Mo, along with most other iron meteorite groups. Variation along this line was caused by mixing between at least two nebular components. One component was likely a pure s-process enriched nucleosynthetic carrier, and the other a homogenized nebular component. Sombrerete, currently classified as an sHL iron, has a Mo isotopic composition that is distinct from all IAB complex meteorites analyzed here. Along with group IVB iron meteorites and some ungrouped iron meteorites, it falls on a separate line from other meteorites which may reflect addition of an r-process-enriched component, and it should no longer be classified as a IAB iron.

Lipid composition analysis of milk fats from different mammalian species: potential for use as human milk fat substitutes.

PubMed

Zou, Xiaoqiang; Huang, Jianhua; Jin, Qingzhe; Guo, Zheng; Liu, Yuanfa; Cheong, Lingzhi; Xu, Xuebing; Wang, Xingguo

2013-07-24

The lipid compositions of commercial milks from cow, buffalo, donkey, sheep, and camel were compared with that of human milk fat (HMF) based on total and sn-2 fatty acid, triacylglycerol (TAG), phospholipid, and phospholipid fatty acid compositions and melting and crystallization profiles, and their degrees of similarity were digitized and differentiated by an evaluation model. The results showed that these milk fats had high degrees of similarity to HMF in total fatty acid composition. However, the degrees of similarity in other chemical aspects were low, indicating that these milk fats did not meet the requirements of human milk fat substitutes (HMFSs). However, an economically feasible solution to make these milks useful as raw materials for infant formula production could be to modify these fats, and a possible method is blending of polyunsaturated fatty acids (PUFA) and 1,3-dioleoyl-2-palmitoylglycerol (OPO) enriched fats and minor lipids based on the corresponding chemical compositions of HMF.

A biological stone from a medieval cemetery in Poland.

PubMed

Gładykowska-Rzeczycka, Judyta J; Nowakowski, Dariusz

2014-01-01

A review of the literature shows that origination of biological stones as well as their pathogenesis mostly depend on the environmental factors. As a result, the structural spectrum of such calculi and their chemical composition are highly diversified. It is well known that biological stones are formed mostly in the digestive and urinary tracts. However, it has been demonstrated that this kind of stony structure can be also, though rarely, found in circulatory and reproductive systems, skin, mucosa, and tear ducts. Although in palaeopathology, the list of biological stones is enriched by stony tumours and/or discharges, it is very difficult to uncover the small size deposits in excavation material. In the literature such findings, originating from different countries and centuries, are few. The described stone was found among the bones of an adult individual in the medieval cemetery of Gdańsk (Poland). The SEM, X-ray spectrometer and chemical evaluation revealed that it was a bladder calculus.

A Biological Stone from a Medieval Cemetery in Poland

PubMed Central

Gładykowska-Rzeczycka, Judyta J.; Nowakowski, Dariusz

2014-01-01

A review of the literature shows that origination of biological stones as well as their pathogenesis mostly depend on the environmental factors. As a result, the structural spectrum of such calculi and their chemical composition are highly diversified. It is well known that biological stones are formed mostly in the digestive and urinary tracts. However, it has been demonstrated that this kind of stony structure can be also, though rarely, found in circulatory and reproductive systems, skin, mucosa, and tear ducts. Although in palaeopathology, the list of biological stones is enriched by stony tumours and/or discharges, it is very difficult to uncover the small size deposits in excavation material. In the literature such findings, originating from different countries and centuries, are few. The described stone was found among the bones of an adult individual in the medieval cemetery of Gdańsk (Poland). The SEM, X-ray spectrometer and chemical evaluation revealed that it was a bladder calculus. PMID:25275551

Metal removal from Municipal Solid Waste Incineration fly ash: A comparison between chemical leaching and bioleaching.

PubMed

Funari, V; Mäkinen, J; Salminen, J; Braga, R; Dinelli, E; Revitzer, H

2017-02-01

Bio- and hydrometallurgical experimental setups at 2-l reactor scale for the processing of fly ash from municipal waste incinerators were explored. We aimed to compare chemical H 2 SO 4 leaching and bioleaching; the latter involved the use of H 2 SO 4 and a mixed culture of acidophilic bacteria. The leaching yields of several elements, including some of those considered as critical (Mg, Co, Ce, Cr, Ga, Nb, Nd, Sb and Sm), are provided. At the end of the experiments, both leaching methods resulted in comparable yields for Mg and Zn (>90%), Al and Mn (>85%), Cr (∼65%), Ga (∼60%), and Ce (∼50%). Chemical leaching showed the best yields for Cu (95%), Fe (91%), and Ni (93%), whereas bioleaching was effective for Nd (76%), Pb (59%), and Co (55%). The two leaching methods generated solids of different quality with respect to the original material as we removed and significantly reduced the metals amounts, and enriched solutions where metals can be recovered for example as mixed salts for further treatment. Compared to chemical leaching the bioleaching halved the use of H 2 SO 4 , i.e., a part of agent costs, as a likely consequence of bio-produced acid and improved metal solubility. Copyright © 2016 Elsevier Ltd. All rights reserved.

Immobilization of actinides in stable mineral type and ceramic materials (high temperature synthesis)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Starkov, O.; Konovalov, E.

1996-05-01

Alternative vitrification technologies are being developed in the world for the immobilization of high radioactive waste in materials with improved thermodynamic stability, as well as improved chemical and thermal stability and stability to radiation. Oxides, synthesized in the form of analogs to rock-forming minerals and ceramics, are among those materials that have highly stable properties and are compatible with the environment. In choosing the appropriate material, we need to be guided by its geometric stability, the minimal number of cations in the structure of the material and the presence of structural elements in the mineral that are isomorphs of uraniummore » and thorium, actinoids found in nature. Rare earth elements, yttrium, zirconium and calcium are therefore suitable. The minerals listed in the table (with the exception of the zircon) are pegatites by origin, i.e. they are formed towards the end of the magma crystallization of silicates form the residual melt, enriched with Ta, Nb, Ti, Zr, Ce, Y, U and Th. Uranium and thorium in the form of isomorphic admixtures form part of the lattice of the mineral. These minerals, which are rather simple in composition and structure and are formed under high temperatures, may be viewed as natural physio-chemical systems that are stable and long-lived in natural environments. The similarity of the properties of actinoids and lanthanoids plays an important role in the geochemistry of uranium and thorium; however, uranium (IV) is closer to the {open_quotes}heavy{close_quotes} group of lanthanoids (the yttrium group) while thorium (IV) is closer to the {open_quotes}light{close_quotes} group (the cerium group). That is why rare earth minerals contain uranium and thorium in the form of isomorphic admixtures.« less

Chemical transport during formation and alteration of Martian impact and volcanic deposits

NASA Technical Reports Server (NTRS)

Newsom, H. E.

1992-01-01

Much of the surface of Mars, including volcanic and cratered terrains, probably experienced alteration and degassing processes. These processes may have depleted or enriched many important elements in surface materials, including bedrock, dust, and soils. The composition of the martian soil may represent the best estimate, for some elements, of the average composition of the martian crust, similar to the composition of loess created by glacial action on the Earth. The martian soil may represent the only convenient, globally or regionally averaged sample of the martian crust. In order to understand the composition of the source material for the soil, however, we need to understand the contributions of volcanic vs. impact sources for this material and the chemical fractionations involved in its production. The processes to be addressed include degassing of volcanic deposits, as observed in the Valley of Ten Thousand Smokes at Katmai, Alaska, and degassing of meltbearing impact ejecta as inferred for suevite ejecta sheets at the Ries Crater, and alteration or palagonitization of volcanic deposits, as documented for volcanos in British Columbia and many other volcanic terrains, and impact crater deposits. The process of palagonitization has been the subject of several studies with reference to Mars, and palagonite is a good analogue for the spectroscopic properties of the martian dust. The role of impact in cratering has not been as well studied, although other researchers have established that both degassing and alteration are common features of impact crater deposits. Other relevant sources of experimental data include the extensive literature on the corrosion of nuclear waste glass and leaching of shocked materials.

10 CFR 40.33 - Issuance of a license for a uranium enrichment facility.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Issuance of a license for a uranium enrichment facility. 40.33 Section 40.33 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE MATERIAL License Applications § 40.33 Issuance of a license for a uranium enrichment facility. (a) The Commission...

Scoping study to expedite development of a field deployable and portable instrument for UF6 enrichment assay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, George; Valentine, John D.; Russo, Richard E.

The primary objective of the present study is to identity the most promising, viable technologies that are likely to culminate in an expedited development of the next-generation, field-deployable instrument for providing rapid, accurate, and precise enrichment assay of uranium hexafluoride (UF6). UF6 is typically involved, and is arguably the most important uranium compound, in uranium enrichment processes. As the first line of defense against proliferation, accurate analytical techniques to determine the uranium isotopic distribution in UF6 are critical for materials verification, accounting, and safeguards at enrichment plants. As nuclear fuel cycle technology becomes more prevalent around the world, international nuclearmore » safeguards and interest in UF6 enrichment assay has been growing. At present, laboratory-based mass spectrometry (MS), which offers the highest attainable analytical accuracy and precision, is the technique of choice for the analysis of stable and long-lived isotopes. Currently, the International Atomic Energy Agency (IAEA) monitors the production of enriched UF6 at declared facilities by collecting a small amount (between 1 to 10 g) of gaseous UF6 into a sample bottle, which is then shipped under chain of custody to a central laboratory (IAEA’s Nuclear Materials Analysis Laboratory) for high-precision isotopic assay by MS. The logistics are cumbersome and new shipping regulations are making it more difficult to transport UF6. Furthermore, the analysis is costly, and results are not available for some time after sample collection. Hence, the IAEA is challenged to develop effective safeguards approaches at enrichment plants. In-field isotopic analysis of UF6 has the potential to substantially reduce the time, logistics and expense of sample handling. However, current laboratory-based MS techniques require too much infrastructure and operator expertise for field deployment and operation. As outlined in the IAEA Department of Safeguards Long-Term R&D Plan, 2012–2023, one of the IAEA long-term R&D needs is to “develop tools and techniques to enable timely, potentially real-time, detection of HEU (Highly Enriched Uranium) production in LEU (Lowly Enriched Uranium) enrichment facilities” (Milestone 5.2). Because it is common that the next generation of analytical instruments is driven by technologies that are either currently available or just now emerging, one reasonable and practical approach to project the next generation of chemical instrumentation is to track the recent trends and to extrapolate them. This study adopted a similar approach, and an extensive literature review on existing and emerging technologies for UF6 enrichment assay was performed. The competitive advantages and current limitations of different analytical techniques for in-field UF6 enrichment assay were then compared, and the main gaps between needs and capabilities for their field use were examined. Subsequently, based on these results, technologies for the next-generation field-deployable instrument for UF6 enrichment assay were recommended. The study was organized in a way that a suite of assessment metric was first identified. Criteria used in this evaluation are presented in Section 1 of this report, and the most important ones are described briefly in the next few paragraphs. Because one driving force for in-field UF6 enrichment assay is related to the demanding transportation regulation for gaseous UF6, Section 2 contains a review of solid sorbents that convert and immobilized gaseous UF6 to a solid state, which is regarded as more transportation friendly and is less regulated. Furthermore, candidate solid sorbents, which show promise in mating with existing and emerging assay technologies, also factor into technology recommendations. Extensive literature reviews on existing and emerging technologies for UF6 enrichment assay, covering their scientific principles, instrument options, and current limitations are detailed in Sections 3 and 4, respectively. In Section 5, the technological gaps as well as start-of-the-art and commercial off-the-shelf components that can be adopted to expedite the development of a fieldable or portable UF6 enrichment-assay instrument are identified and discussed. Finally, based on the results of the review, requirements and recommendations for developing the next-generation field-deployable instrument for UF6 enrichment assay are presented in Section 6.« less

DOSE RESPONSE FROM HIGH THROUGHPUT GENE EXPRESSION STUDIES AND THE INFLUENCE OF TIME AND CELL LINE ON INFERRED MODE OF ACTION BY ONTOLOGIC ENRICHMENT (SOT)

EPA Science Inventory

Gene expression with ontologic enrichment and connectivity mapping tools is widely used to infer modes of action (MOA) for therapeutic drugs. Despite progress in high-throughput (HT) genomic systems, strategies suitable to identify industrial chemical MOA are needed. The L1000 is...

The Military Significance of Small Uranium Enrichment Facilities Fed with Low-Enrichment Uranium (Redacted)

DTIC Science & Technology

1969-12-01

a five-year supply of enriched uranium for reactor fuel . Nevertheless, it seems clear that some foreign enrichment developments are approaching a...produc- tion of fissile material could powerfully influence the assessment of risks and benefits of a nuclear weapons development program . Since... program is likely to include the production of its own relatively pure fissile plutonium. This would involve more rapid cycling and reprocessing of fuel

Aerosol Emissions from Great Lakes Harmful Algal Blooms

DOE Office of Scientific and Technical Information (OSTI.GOV)

May, Nathaniel W.; Olson, Nicole E.; Panas, Mark

In freshwater lakes, harmful algal blooms (HABs) of Cyanobacteria (blue-green algae) produce toxins that impact human health. However, little is known about the chemical species present in lake spray aerosol (LSA) produced from wave-breaking in freshwater HABs. In this study, a laboratory LSA generator produced aerosols from freshwater samples collected from Lake Michigan and Lake Erie during HAB and non-bloom conditions. Particles were analyzed for size and chemical composition by single particle mass spectrometry, electron microscopy, and fluorescence microscopy, with three distinct types of LSA identified with varying levels of organic carbon and biological material associated with calcium salts. LSAmore » autofluorescence increases with blue-green algae concentration, showing that organic molecules of biological origin are incorporated in LSA from HABs. The number fraction of LSA with biological mass spectral markers also increases with particle diameter (greater than 0.5 μm), showing that HABs have size-dependent impacts on aerosol composition. The highest number fraction of LSA enriched in organic carbon were observed in particles less than 0.5 μm in diameter. Understanding the transfer of organic and biogenic material from freshwater to the atmosphere via LSA particles is crucial for determining health and climate effects due to HABs.« less

Combustion influences on natural abundance nitrogen isotope ratio in soil and plants following a wildfire in a sub-alpine ecosystem.

PubMed

Huber, Edith; Bell, Tina L; Adams, Mark A

2013-11-01

This before-and-after-impact study uses the natural abundance N isotope ratio (δ(15)N) to investigate the effects of a wildfire on sub-alpine ecosystem properties and processes. We measured the (15)N signatures of soil, charred organic material, ash and foliage in three sub-alpine plant communities (grassland, heathland and woodland) in south-eastern Australia. Surface bulk soil was temporarily enriched in (15)N immediately after wildfire compared to charred organic material and ash in all plant communities. We associated the enrichment of bulk soil with fractionation of N during combustion and volatilization of N, a process that also explains the sequential enrichment of (15)N of unburnt leaves > ash > charred organic material in relation to duration and intensity of heating. The rapid decline in (15)N of bulk soil to pre-fire values indicates that depleted ash, containing considerable amounts of total N, was readily incorporated into the soil. Foliar δ(15)N also increased with values peaking 1 year post-fire. Foliar enrichment was foremost coupled with the release of enriched NH4(+) into the soil owing to isotopic discrimination during volatilization of soluble N and combustion of organic material. The mode of post-fire regeneration influenced foliar (15)N enrichment in two species indicating use of different sources of N following fire. The use of natural abundance of (15)N in soil, ash and foliage as a means of tracing transformation of N during wildfire has established the importance of combustion products as an important, albeit temporary source of inorganic N for plants regenerating after wildfire.

From Dust to Planets: The Tale Told by Moderately Volatile Element Depletion (MOVED)

NASA Technical Reports Server (NTRS)

Yin, Qing-Zhu

2004-01-01

The pronounced depletion of moderately volatile elements (MOVE, that condense or evaporate at temperatures in the range 1350-650K) relative to the average solar composition is a characteristic feature in most primitive chondrites and bulk terrestrial planets. It differs from the composition of the Sun and from the materials further away from the Sun (CI chondrites). None of the remaining planets or even meteorites shows an enrichment of volatile elements that would balance the depletion in the inner Solar System. Whether this depletion occurred in solar nebular stage or in planetary formation stage has been the subject of long lasting debate. The search for mysterite initiated in 1973 continues today in search of lost planets. Here I show that the MOVED patterns demonstrate a clear connection between the rocky materials of the inner solar system and the interstellar dust. The inheritance of interstellar materials by the solar system is not only documented by the presence of presolar grains, various isotopic anomalies, but also expressed in the chemical element distribution in the inner solar system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panasyuk,A.; Rosenthal,M.; Efremov, G. V.

Multilateral mechanisms for the fuel cycle are seen as a potentially important way to create an industrial infrastructure that will support a renaissance and at the same time not contribute to the risk of nuclear proliferation. In this way, international nuclear fuel cycle centers for enrichment can help to provide an assurance of supply of nuclear fuel that will reduce the likelihood that individual states will pursue this sensitive technology, which can be used to produce nuclear material directly usable nuclear weapons. Multinational participation in such mechanisms can also potentially promote transparency, build confidence, and make the implementation of IAEAmore » safeguards more effective or more efficient. At the same time, it is important to ensure that there is no dissemination of sensitive technology. The Russian Federation has taken a lead role in this area by establishing an International Uranium Enrichment Center (IUEC) for the provision of enrichment services at its uranium enrichment plant located at the Angarsk Electrolysis Chemical Complex (AECC). This paper describes how the IUEe is organized, who its members are, and the steps that it has taken both to provide an assured supply of nuclear fuel and to ensure protection of sensitive technology. It also describes the relationship between the IUEC and the IAEA and steps that remain to be taken to enhance its assurance of supply. Using the IUEC as a starting point for discussion, the paper also explores more generally the ways in which features of such fuel cycle centers with multinational participation can have an impact on safeguards arrangements, transparency, and confidence-building. Issues include possible lAEA safeguards arrangements or other links to the IAEA that might be established at such fuel cycle centers, impact of location in a nuclear weapon state, and the transition by the IAEA to State Level safeguards approaches.« less

Neutralization of Plutonium and Enriched Uranium Solutions Containing Gadolinium as a Neutron Poison

DOE Office of Scientific and Technical Information (OSTI.GOV)

BRONIKOWSKI, MG.

2004-04-01

Materials currently being dissolved in the HB-Line Facility will result in an accumulated solution containing an estimated uranium:plutonium (U:Pu) ratio of 4.3:1 and an 235U enrichment estimated at 30 per cent The U:Pu ratio and the enrichment are outside the evaluated concentration range for disposition to high level waste (HLW) using gadolinium (Gd) as a neutron poison. To confirm that the solution generated during the current HB-Line dissolving campaign can be poisoned with Gd, neutralized and discarded to the Savannah River Site (SRS) high level waste (HLW) system without undue nuclear safety concerns the caustic precipitation of surrogate solutions wasmore » examined. Experiments were performed with a U/Pu/Gd solution representative of the HB-Line estimated concentration ratio and also a U/Gd solution. Depleted U was used in the experiments as the enrichment of the U will not affect the chemical behavior during neutralization, but will affect the amount of Gd added to the solution. Settling behavior of the neutralized solutions was found to be comparable to previous studies. The neutralized solutions mixed easily and had expected densities of typical neutralized waste. The neutralized solids were found to be homogeneous and less than 20 microns in size. Partially neutralized solids were more amorphous than the fully neutralized solids. Based on the results of these experiments, Gd was found to be a viable poison for neutralizing a U/Pu/Gd solution with a U:Pu mass ratio of 4.3:1 thus extending the U:Pu mass ratio from the previously investigated 0-3:1 to 4.3:1. However, further work is needed to allow higher U concentrations or U:Pu ratios greater than investigated in this work.« less

A strong enrichment of potentially toxic elements (PTEs) in Nord-Trøndelag (central Norway) forest soil.

PubMed

Reimann, C; Fabian, K; Schilling, J; Roberts, D; Englmaier, P

2015-12-01

Analysis of soil C and O horizon samples in a recent regional geochemical survey of Nord-Trøndelag, central Norway (752 sample sites covering 25,000 km2), identified a strong enrichment of several potentially toxic elements (PTEs) in the O horizon. Of 53 elements analysed in both materials, Cd concentrations are, on average, 17 times higher in the O horizon than in the C horizon and other PTEs such as Ag (11-fold), Hg (10-fold), Sb (8-fold), Pb (4-fold) and Sn (2-fold) are all strongly enriched relative to the C horizon. Geochemical maps of the survey area do not reflect an impact from local or distant anthropogenic contamination sources in the data for O horizon soil samples. The higher concentrations of PTEs in the O horizon are the result of the interaction of the underlying geology, the vegetation zone and type, and climatic effects. Based on the general accordance with existing data from earlier surveys in other parts of northern Europe, the presence of a location-independent, superordinate natural trend towards enrichment of these elements in the O horizon relative to the C horizon soil is indicated. The results imply that the O and C horizons of soils are different geochemical entities and that their respective compositions are controlled by different processes. Local mineral soil analyses (or published data for the chemical composition of the average continental crust) cannot be used to provide a geochemical background for surface soil. At the regional scale used here surface soil chemistry is still dominated by natural sources and processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Metal enrichment of the intracluster medium: SN-driven galactic winds

NASA Astrophysics Data System (ADS)

Baumgartner, V.; Breitschwerdt, D.

2009-12-01

% We investigate the role of supernova (SN)-driven galactic winds in the chemical enrichment of the intracluster medium (ICM). Such outflows on galactic scales have their origin in huge star forming regions and expel metal enriched material out of the galaxies into their surroundings as observed, for example, in the nearby starburst galaxy NGC 253. As massive stars in OB-associations explode sequentially, shock waves are driven into the interstellar medium (ISM) of a galaxy and merge, forming a superbubble (SB). These SBs expand in a direction perpendicular to the disk plane following the density gradient of the ISM. We use the 2D analytical approximation by Kompaneets (1960) to model the expansion of SBs in an exponentially stratified ISM. This is modified in order to describe the sequence of SN-explosions as a time-dependent process taking into account the main-sequence life-time of the SN-progenitors and using an initial mass function to get the number of massive stars per mass interval. The evolution of the bubble in space and time is calculated analytically, from which the onset of Rayleigh-Taylor instabilities in the shell can be determined. In its further evolution, the shell will break up and high-metallicity gas will be ejected into the halo of the galaxy and even into the ICM. We derive the number of stars needed for blow-out depending on the scale height and density of the ambient medium, as well as the fraction of alpha- and iron peak elements contained in the hot gas. Finally, the amount of metals injected by Milky Way-type galaxies to the ICM is calculated confirming the importance of this enrichment process.

The Perils of Partition: Difficulties in Retrieving Magma Compositions from Chemically Equilibrated Basaltic Meteorites

NASA Technical Reports Server (NTRS)

Treiman, Allan H.

1996-01-01

The chemical compositions of magmas can be derived from the compositions of their equilibrium minerals through mineral/magma partition coefficients. This method cannot be applied safely to basaltic rocks, either solidified lavas or cumulates, which have chemically equilibrated or partially equilibrated at subsolidus temperatures, i.e., in the absence of magma. Applying mineral/ melt partition coefficients to mineral compositions from such rocks will typically yield 'magma compositions' that are strongly fractionated and unreasonably enriched in incompatible elements (e.g., REE's). In the absence of magma, incompatible elements must go somewhere; they are forced into minerals (e.g., pyroxenes, plagioclase) at abundance levels far beyond those established during normal mineral/magma equilibria. Further, using mineral/magma partition coefficients with such rocks may suggest that different minerals equilibrated with different magmas, and the fractionation sequence of those melts (i.e., enrichment in incompatible elements) may not be consistent with independent constraints on the order of crystallization. Subsolidus equilibration is a reasonable cause for incompatible- element-enriched minerals in some eucrites, diogenites, and martian meteorites and offers a simple alternative to petrogenetic schemes involving highly fractionated magmas or magma infiltration metasomatism.

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacLeod, Bradley A.; Stanton, Noah J.; Gould, Isaac E.

Lightweight, robust, and flexible single-walled carbon nanotube (SWCNT) materials can be processed inexpensively using solution-based techniques, similar to other organic semiconductors. In contrast to many semiconducting polymers, semiconducting SWCNTs (s-SWCNTs) represent unique one-dimensional organic semiconductors with chemical and physical properties that facilitate equivalent transport of electrons and holes. These factors have driven increasing attention to employing s-SWCNTs for electronic and energy harvesting applications, including thermoelectric (TE) generators. Here we demonstrate a combination of ink chemistry, solid-state polymer removal, and charge-transfer doping strategies that enable unprecedented n-type and p-type TE power factors, in the range of 700 μW m –1 Kmore » –2 at 298 K for the same solution-processed highly enriched thin films containing 100% s-SWCNTs. We also demonstrate that the thermal conductivity appears to decrease with decreasing s-SWCNT diameter, leading to a peak material zT ≈ 0.12 for s-SWCNTs with diameters in the range of 1.0 nm. Here, our results indicate that the TE performance of s-SWCNT-only material systems is approaching that of traditional inorganic semiconductors, paving the way for these materials to be used as the primary components for efficient, all-organic TE generators.« less

Isotopic homogeneity of iron in the early solar nebula.

PubMed

Zhu, X K; Guo, Y; O'Nions, R K; Young, E D; Ash, R D

2001-07-19

The chemical and isotopic homogeneity of the early solar nebula, and the processes producing fractionation during its evolution, are central issues of cosmochemistry. Studies of the relative abundance variations of three or more isotopes of an element can in principle determine if the initial reservoir of material was a homogeneous mixture or if it contained several distinct sources of precursor material. For example, widespread anomalies observed in the oxygen isotopes of meteorites have been interpreted as resulting from the mixing of a solid phase that was enriched in 16O with a gas phase in which 16O was depleted, or as an isotopic 'memory' of Galactic evolution. In either case, these anomalies are regarded as strong evidence that the early solar nebula was not initially homogeneous. Here we present measurements of the relative abundances of three iron isotopes in meteoritic and terrestrial samples. We show that significant variations of iron isotopes exist in both terrestrial and extraterrestrial materials. But when plotted in a three-isotope diagram, all of the data for these Solar System materials fall on a single mass-fractionation line, showing that homogenization of iron isotopes occurred in the solar nebula before both planetesimal accretion and chondrule formation.

Uranium distribution in pseudowollastonite slag from a phosphorus furnace

USGS Publications Warehouse

Young, Edward; Altschuler, Zalman S.

1956-01-01

Silicate slag from the Victor Chemical Company phosphorus furnace at Tarpon Springs, Fla., has been found to consist essentially of pseudowollastonite, α-CaSiO3. The first-formed crystals are euhedral laths which form a mesh making up most of the slag. As the slag continues to solidify, its composition changes slightly and more equant, subhedral crystals of pseudowollastonite are deposited within the framework of the earlier material. Finally, anherdral masses of fibrous, poorly crystallized material are deposited in the remaining pore spaces which are not always completely filled. Spherules of iron phosphide, Fe2P, occur very sparsely in the slag as inclusions from the immiscible iron phosphide melt. Uranium content increases in the later crystal products of the slag, and by heavy-liquid fractionation it has been possible to segregate partially the phases and to obtain a fourfold concentration of uranium in 5 percent of the material and a twofold concentration in 30 percent of the material. Nuclear-emulsion studies indicate that the last phases of the silicate slag are actually eight times as radioactive as the early phases. In addition, the iron phosphide spherules are comparably enriches in uranium.

Thermal Infrared Emission Spectroscopy of Synthetic Allophane and its Potential Formation on Mars

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Kraft, M. D.; Sharp, T. G.; Golden, D. C.; Ming, Douglas W.

2010-01-01

Allophane is a poorly-crystalline, hydrous aluminosilicate with variable Si/Al ratios approx.0.5-1 and a metastable precursor of clay minerals. On Earth, it forms rapidly by aqueous alteration of volcanic glass under neutral to slightly acidic conditions [1]. Based on in situ chemical measurements and the identification of alteration phases [2-4], the Martian surface is interpreted to have been chemically weathered on local to regional scales. Chemical models of altered surfaces detected by the Mars Exploration Rover Spirit in Gusev crater suggest the presence of an allophane-like alteration product [3]. Thermal infrared (TIR) spectroscopy and spectral deconvolution models are primary tools for determining the mineralogy of the Martian surface [5]. Spectral models of data from the Thermal Emission Spectrometer (TES) indicate a global compositional dichotomy, where high latitudes tend to be enriched in a high-silica material [6,7], interpreted as high-silica, K-rich volcanic glass [6,8]. However, later interpretations proposed that the high-silica material may be an alteration product (such as amorphous silica, clay minerals, or allophane) and that high latitude surfaces are chemically weathered [9-11]. A TIR spectral library of pure minerals is available for the public [12], but it does not contain allophane spectra. The identification of allophane on the Martian surface would indicate high water activity at the time of its formation and would help constrain the aqueous alteration environment [13,14]. The addition of allophane to the spectral library is necessary to address the global compositional dichotomy. In this study, we characterize a synthetic allophane by IR spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM) to create an IR emission spectrum of pure allophane for the Mars science community to use in Martian spectral models.

EDXRF as an alternative method for multielement analysis of tropical soils and sediments.

PubMed

Fernández, Zahily Herrero; Dos Santos Júnior, José Araújo; Dos Santos Amaral, Romilton; Alvarez, Juan Reinaldo Estevez; da Silva, Edvane Borges; De França, Elvis Joacir; Menezes, Rômulo Simões Cezar; de Farias, Emerson Emiliano Gualberto; do Nascimento Santos, Josineide Marques

2017-08-10

The quality assessment of tropical soils and sediments is still under discussion, with efforts being made on the part of governmental agencies to establish reference values. Energy dispersive X-ray fluorescence (EDXRF) is a potential analytical technique for quantifying diverse chemical elements in geological material without chemical treatment, primarily when it is performed at an appropriate metrological level. In this work, analytical curves were obtained by means of the analysis of geological reference materials (RMs), which allowed for the researchers to draw a comparison among the sources of analytical uncertainty. After having determined the quality assurance of the analytical procedure, the EDXRF method was applied to determine chemical elements in soils from the state of Pernambuco, Brazil. The regression coefficients of the analytical curves used to determine Al, Ca, Fe, K, Mg, Mn, Ni, Pb, Si, Sr, Ti, and Zn were higher than 0.99. The quality of the analytical procedure was demonstrated at a 95% confidence level, in which the estimated analytical uncertainties agreed with those from the RM's certificates of analysis. The analysis of diverse geological samples from Pernambuco indicated higher concentrations of Ni and Zn in sugarcane, with maximum values of 41 mg kg - 1 and 118 mg kg - 1 , respectively, and agricultural areas (41 mg kg - 1 and 127 mg kg - 1 , respectively). The trace element Sr was mainly enriched in urban soils with values of 400 mg kg - 1 . According to the results, the EDXRF method was successfully implemented, providing some chemical tracers for the quality assessment of tropical soils and sediments.

SPECHT - single-stage phosphopeptide enrichment and stable-isotope chemical tagging: quantitative phosphoproteomics of insulin action in muscle.

PubMed

Kettenbach, Arminja N; Sano, Hiroyuki; Keller, Susanna R; Lienhard, Gustav E; Gerber, Scott A

2015-01-30

The study of cellular signaling remains a significant challenge for translational and clinical research. In particular, robust and accurate methods for quantitative phosphoproteomics in tissues and tumors represent significant hurdles for such efforts. In the present work, we design, implement and validate a method for single-stage phosphopeptide enrichment and stable isotope chemical tagging, or SPECHT, that enables the use of iTRAQ, TMT and/or reductive dimethyl-labeling strategies to be applied to phosphoproteomics experiments performed on primary tissue. We develop and validate our approach using reductive dimethyl-labeling and HeLa cells in culture, and find these results indistinguishable from data generated from more traditional SILAC-labeled HeLa cells mixed at the cell level. We apply the SPECHT approach to the quantitative analysis of insulin signaling in a murine myotube cell line and muscle tissue, identify known as well as new phosphorylation events, and validate these phosphorylation sites using phospho-specific antibodies. Taken together, our work validates chemical tagging post-single-stage phosphoenrichment as a general strategy for studying cellular signaling in primary tissues. Through the use of a quantitatively reproducible, proteome-wide phosphopeptide enrichment strategy, we demonstrated the feasibility of post-phosphopeptide purification chemical labeling and tagging as an enabling approach for quantitative phosphoproteomics of primary tissues. Using reductive dimethyl labeling as a generalized chemical tagging strategy, we compared the performance of post-phosphopeptide purification chemical tagging to the well established community standard, SILAC, in insulin-stimulated tissue culture cells. We then extended our method to the analysis of low-dose insulin signaling in murine muscle tissue, and report on the analytical and biological significance of our results. Copyright © 2014 Elsevier B.V. All rights reserved.

Guide for Oxygen Hazards Analyses on Components and Systems

NASA Technical Reports Server (NTRS)

Stoltzfus, Joel M.; Dees, Jesse; Poe, Robert F.

1996-01-01

Because most materials, including metals, will burn in an oxygen-enriched environment, hazards are always present when using oxygen. Most materials will ignite at lower temperatures in an oxygen-enriched environment than in air, and once ignited, combustion rates are greater in the oxygen-enriched environment. Many metals burn violently in an oxygen-enriched environment when ignited. Lubricants, tapes, gaskets, fuels, and solvents can increase the possibility of ignition in oxygen systems. However, these hazards do not preclude the use of oxygen. Oxygen may be safely used if all the materials in a system are not flammable in the end-use environment or if ignition sources are identified and controlled. These ignition and combustion hazards necessitate a proper oxygen hazards analysis before introducing a material or component into oxygen service. The objective of this test plan is to describe the White Sands Test Facility oxygen hazards analysis to be performed on components and systems before oxygen is introduced and is recommended before implementing the oxygen component qualification procedure. The plan describes the NASA Johnson Space Center White Sands Test Facility method consistent with the ASTM documents for analyzing the hazards of components and systems exposed to an oxygen-enriched environment. The oxygen hazards analysis is a useful tool for oxygen-system designers, system engineers, and facility managers. Problem areas can be pinpointed before oxygen is introduced into the system, preventing damage to hardware and possible injury or loss of life.

Pervaporation of phenols

DOEpatents

Boddeker, Karl W.

1989-01-01

Aqueous phenolic solutions are separated by pervaporation to yield a phenol-depleted retentate and a phenol-enriched permeate. The separation effect is enhanced by phase segregation into two immiscible phases, "phenol in water" (approximately 10% phenol), and "water in phenol" (approximately 70% phenol). Membranes capable of enriching phenols by pervaporation include elastomeric polymers and anion exchange membranes, membrane selection and process design being guided by pervaporation performance and chemical stability towards phenolic solutions. Single- and multiple-stage procresses are disclosed, both for the enrichment of phenols and for purification of water from phenolic contamination.

Pervaporation of phenols

DOEpatents

Boddeker, K.W.

1989-02-21

Aqueous phenolic solutions are separated by pervaporation to yield a phenol-depleted retentate and a phenol-enriched permeate. The separation effect is enhanced by phase segregation into two immiscible phases, phenol in water'' (approximately 10% phenol), and water in phenol'' (approximately 70% phenol). Membranes capable of enriching phenols by pervaporation include elastomeric polymers and anion exchange membranes, membrane selection and process design being guided by pervaporation performance and chemical stability towards phenolic solutions. Single- and multiple-stage processes are disclosed, both for the enrichment of phenols and for purification of water from phenolic contamination. 8 figs.

[Effects of ecosystem structure on the organic aggregates physical and chemical parameters of Lake Taihu].

PubMed

Chao, Jian-Ying; Gao, Guang; Tang, Xiang-Ming; Shen, Yan; Zhu, Li-Ping

2009-11-01

The abundance, organic matter content and chemical composition of organic aggregation (OA) were monitored in Lake Taihu in different ecotype sites from January to December in 2007, and other water physical and chemical parameters were concomitantly monitored. The OA abundance was increasing along regional and P-enrichment gradients, and there were significant differences in OA characteristic in different ecotypes. Moreover, wind is one important factor that contributes to OA characteristic in Lake Taihu. OA maybe one potential important nutrient source in lake water for its high enrichment factors of nutrition: the concentrations of P and N in the OA were much higher than that of in the water; more than one third (43.3%) of TP could be attributed to the OA-P, and that number of OA-N is 16.5%.

Surface abundances of ON stars

NASA Astrophysics Data System (ADS)

Martins, F.; Simón-Díaz, S.; Palacios, A.; Howarth, I.; Georgy, C.; Walborn, N. R.; Bouret, J.-C.; Barbá, R.

2015-06-01

Context. Massive stars burn hydrogen through the CNO cycle during most of their evolution. When mixing is efficient or when mass transfer in binary systems occurs, chemically processed material is observed at the surface of O and B stars. Aims: ON stars show stronger lines of nitrogen than morphologically normal counterparts. Whether this corresponds to the presence of material processed through the CNO cycle is not known. Our goal is to answer this question. Methods: We performed a spectroscopic analysis of a sample of ON stars with atmosphere models. We determined the fundamental parameters as well as the He, C, N, and O surface abundances. We also measured the projected rotational velocities. We compared the properties of the ON stars to those of normal O stars. Results: We show that ON stars are usually rich in helium. Their CNO surface abundances are fully consistent with predictions of nucleosynthesis. ON stars are more chemically evolved and rotate - on average - faster than normal O stars. Evolutionary models including rotation cannot account for the extreme enrichment observed among ON main sequence stars. Some ON stars are members of binary systems, but others are single stars as indicated by stable radial velocities. Mass transfer is therefore not a simple explanation for the observed chemical properties. Conclusions: We conclude that ON stars show extreme chemical enrichment at their surface, consistent with nucleosynthesis through the CNO cycle. Its origin is not clear at present. Based on observations obtained 1) at the Anglo-Australian Telescope; 2) at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii; 3) at the ESO/La Silla Observatory under programs 081.D-2008, 083.D-0589, 086.D-0997; 4) the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias; 5) the Mercator Telescope, operated on the island of La Palma by the Flemish Community at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.Appendices are available in electronic form at http://www.aanda.orgThe reduced spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/578/A109

Ionic Liquids as a Basis Context for Developing High school Chemistry Teaching Materials

NASA Astrophysics Data System (ADS)

Hernani; Mudzakir, A.; Sumarna, O.

2017-02-01

This research aims to produce a map of connectedness highschool chemical content with the context of the modern chemical materials applications based on ionic liquids. The research method is content analysis of journal articles related to the ionic liquid materials and the textbooks of high school chemistry and textbooks of general chemistry at the university. The instrument used is the development format of basic text that connect and combine content and context. The results showed the connectedness between: (1) the context lubricants ionic liquid with the content of ionic bonding, covalent bonding, metal bonding, interaction between the particles of matter, the elements of main group, the elements of transition group, and the classification of macromolecules; (2) the context of fuel cell electrolite with the content of ionic bonding, covalent bonding, metal bonding, interaction between the particles of matter, Volta cell, and electrolysis cell; (3) the contect of nanocellulose with the content of ionic bonding, covalent bonding, metal bonding, interaction between the particles of matter, colloid, carbon compound, and the classification of macromolecules; and (4) the context of artificial muscle system with the content of ionic bond, covalent bond, metal bonding, interaction between the particles of matter, hydrocarbons, electrolytes and non-electrolytes, and the classification of macromolecules. Based on the result of this content analysis, the context of ionic liquid is predicted can be utilized for the enrichment of high school chemistry and has the potential to become teaching material’s context of high school chemistry in the future.

Preservation Methods Alter Carbon and Nitrogen Stable Isotope Values in Crickets (Orthoptera: Grylloidea)

PubMed Central

Jesus, Fabiene Maria; Pereira, Marcelo Ribeiro; Rosa, Cassiano Sousa; Moreira, Marcelo Zacharias; Sperber, Carlos Frankl

2015-01-01

Stable isotope analysis (SIA) is an important tool for investigation of animal dietary habits for determination of feeding niche. Ideally, fresh samples should be used for isotopic analysis, but logistics frequently demands preservation of organisms for analysis at a later time. The goal of this study was to establish the best methodology for preserving forest litter-dwelling crickets for later SIA analysis without altering results. We collected two cricket species, Phoremia sp. and Mellopsis doucasae, from which we prepared 70 samples per species, divided among seven treatments: (i) freshly processed (control); preserved in fuel ethanol for (ii) 15 and (iii) 60 days; preserved in commercial ethanol for (iv) 15 and (v) 60 days; fresh material frozen for (vi) 15 and (vii) 60 days. After oven drying, samples were analyzed for δ 15N, δ 13C values, N(%), C(%) and C/N atomic values using continuous flow isotope ratio mass spectrometry. All preservation methods tested, significantly impacted δ 13C and δ 15N and C/N atomic values. Chemical preservatives caused δ 13C enrichment as great as 1.5‰, and δ 15N enrichment as great as 0.9‰; the one exception was M. doucasae stored in ethanol for 15 days, which had δ 15N depletion up to 1.8‰. Freezing depleted δ 13C and δ 15N by up to 0.7 and 2.2‰, respectively. C/N atomic values decreased when stored in ethanol, and increased when frozen for 60 days for both cricket species. Our results indicate that all preservation methods tested in this study altered at least one of the tested isotope values when compared to fresh material (controls). We conclude that only freshly processed material provides adequate SIA results for litter-dwelling crickets. PMID:26390400

Preservation Methods Alter Carbon and Nitrogen Stable Isotope Values in Crickets (Orthoptera: Grylloidea).

PubMed

Jesus, Fabiene Maria; Pereira, Marcelo Ribeiro; Rosa, Cassiano Sousa; Moreira, Marcelo Zacharias; Sperber, Carlos Frankl

2015-01-01

Stable isotope analysis (SIA) is an important tool for investigation of animal dietary habits for determination of feeding niche. Ideally, fresh samples should be used for isotopic analysis, but logistics frequently demands preservation of organisms for analysis at a later time. The goal of this study was to establish the best methodology for preserving forest litter-dwelling crickets for later SIA analysis without altering results. We collected two cricket species, Phoremia sp. and Mellopsis doucasae, from which we prepared 70 samples per species, divided among seven treatments: (i) freshly processed (control); preserved in fuel ethanol for (ii) 15 and (iii) 60 days; preserved in commercial ethanol for (iv) 15 and (v) 60 days; fresh material frozen for (vi) 15 and (vii) 60 days. After oven drying, samples were analyzed for δ15N, δ13C values, N(%), C(%) and C/N atomic values using continuous flow isotope ratio mass spectrometry. All preservation methods tested, significantly impacted δ13C and δ15N and C/N atomic values. Chemical preservatives caused δ13C enrichment as great as 1.5‰, and δ15N enrichment as great as 0.9‰; the one exception was M. doucasae stored in ethanol for 15 days, which had δ15N depletion up to 1.8‰. Freezing depleted δ13C and δ15N by up to 0.7 and 2.2‰, respectively. C/N atomic values decreased when stored in ethanol, and increased when frozen for 60 days for both cricket species. Our results indicate that all preservation methods tested in this study altered at least one of the tested isotope values when compared to fresh material (controls). We conclude that only freshly processed material provides adequate SIA results for litter-dwelling crickets.

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Amount of liability insurance required for uranium... required for uranium enrichment facilities. Each holder of a license issued under Parts 40 or 70 of this chapter for a uranium enrichment facility that involves the use of source material or special nuclear...

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 2 2012-01-01 2012-01-01 false Amount of liability insurance required for uranium... required for uranium enrichment facilities. Each holder of a license issued under Parts 40 or 70 of this chapter for a uranium enrichment facility that involves the use of source material or special nuclear...

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 2 2013-01-01 2013-01-01 false Amount of liability insurance required for uranium... required for uranium enrichment facilities. Each holder of a license issued under Parts 40 or 70 of this chapter for a uranium enrichment facility that involves the use of source material or special nuclear...

10 CFR 140.13b - Amount of liability insurance required for uranium enrichment facilities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 2 2014-01-01 2014-01-01 false Amount of liability insurance required for uranium... required for uranium enrichment facilities. Each holder of a license issued under Parts 40 or 70 of this chapter for a uranium enrichment facility that involves the use of source material or special nuclear...

Isotopic Anomalies in Primitive Solar System Matter: Spin-State-Dependent Fractionation of Nitrogen and Deuterium in Interstellar Clouds

NASA Technical Reports Server (NTRS)

Wirstrom, Eva S.; Charnley, Steven B.; Cordiner, Martin A.; Milam, Stefanie N.

2012-01-01

Organic material found in meteorites and interplanetary dust particles is enriched in D and N-15. This is consistent with the idea that the functional groups carrying these isotopic anomalies, nitriles and amines, were formed by ion-molecule chemistry in the protosolar nebula, Theoretical models of interstellar fractionation at low temperatures predict large enrichments in both D and N-15 and can account for the largest isotopic enrichments measured in carbonaceous meteorites. However, more recent measurements have shown that, in some primitive samples, a large N-15 enrichment does not correlate with one in D, and that some D-enriched primitive material displays little, if any, N-15 enrichment. By considering the spin-state dependence in ion-molecule reactions involving the ortho and para forms of H2, we show that ammonia and related molecules can exhibit such a wide range of fractionation for both N-15 and D in dense cloud cores. We also show that while the nitriles, HCN and HNC, contain the greatest N=15 enrichment, this is not expected to correlate with extreme D enrichment. These calculations therefore support the view that solar system N-15 and D isotopic anomalies have an interstellar heritage. We also compare our results to existing astronomical observations and briefly discuss future tests of this model.

Chemical characterisation of dredged sediments in relation to their potential use in civil engineering.

PubMed

Zuliani, Tea; Mladenovič, Ana; Ščančar, Janez; Milačič, Radmila

2016-04-01

During capital and/or maintenance dredging operations, large amounts of material are produced. Instead of their discharge, dredged sediments may be a valuable natural resource if not contaminated. One of the possible areas of application is civil engineering. In the present work, the environmental status of seaport dredged sediment was evaluated in order to investigate its potential applicability as a secondary raw material. Sediments were analysed for element concentrations in digested samples, aqueous extracts and fractions from sequential extraction; for fluoride, chloride and sulphate concentrations in aqueous extracts; and for tributyltin (TBT). Granulometric and mineralogical compositions were also analysed. The elemental impact was evaluated by calculation of the enrichment factors. The total element concentrations determined showed moderate contamination of the dredged sediments as was confirmed also by their moderate enrichment factors, presumably as a result of industrial and port activities. Elemental concentrations in the aqueous extract were very low and therefore do not represent any hazard for the environment. The water-soluble element concentrations were under the threshold levels set by the EU Directive on the landfill of waste, on the basis of which the applicability of dredged sediments in civil engineering is evaluated, while the content of chloride and sulphate were above the threshold levels. It was found out that due to the large amounts of sediment available, civil engineering applications such as the construction of embankments and backfilling is the most beneficial recycling solution at present.

The Alpha Particle X-Ray Spectrometer (APXS): Results from Gusev Crater and Calibration Report

NASA Technical Reports Server (NTRS)

Gellert, R.; Rieder, R.; Brueckner, J.; Clark, B.; Dreibus, G.; Klingelhoefer, G.; Lugmair, G.; Ming, D.; Waenke, H.; Yen, A.;

Initial deposition of calcium phosphate ceramic on polystyrene and polytetrafluoroethylene by rf magnetron sputtering deposition

NASA Astrophysics Data System (ADS)

Feddes, B.; Wolke, J. G. C.; Jansen, J. A.; Vredenberg, A. M.

2003-03-01

Calcium phosphate (CaP) coatings can be applied to improve the biological performance of polymeric medical implants. A strong interfacial bond between ceramic and polymer is required for clinical applications. Because the chemical structure of an interface plays an important role in the adhesion of a coating, we studied the formation of the interface between CaP and polystyrene (PS) and polytetrafluoroethylene (PTFE). The coating was deposited in a radio frequency (rf) magnetron sputtering deposition system. Prior to the deposition, some samples received an oxygen plasma pretreatment. We found that the two substrates show a strongly different reactivity towards CaP. On PS a phosphorus and oxygen enrichment is present at the interface. This is understood from POx complexes that are able to bind to the PS. The effects of the plasma pretreatment are overruled by the deposition process itself. On PTFE, a calcium enrichment and an absence of phosphorus is found at the interface. The former is the result of CaF2-like material being formed at the interface. The latter may be the result of phosphorus reacting with escaping fluorine to a PF3 molecule, which than escapes from the material as a gas molecule. We found that the final structure of the interface is mostly controlled by the bombardment of energetic particles escaping either from the plasma or from the sputtering target. The work described here can be used to understand and improve the adhesion of CaP coatings deposited on medical substrates.

Effect of conductive polymers coated anode on the performance of microbial fuel cells (MFCs) and its biodiversity analysis.

PubMed

Li, Chao; Zhang, Libin; Ding, Lili; Ren, Hongqiang; Cui, Hao

2011-06-15

Conductive polymer, one of the most attractive electrode materials, has been applied to coat anode of MFC to improve its performance recently. In this paper, two conductive polymer materials, polyaniline (PANI) and poly(aniline-co-o-aminophenol) (PAOA) were used to modify carbon felt anode and physical and chemical properties of the modified anodes were studied. The power output and biodiversity of modified anodes, along with unmodified carbon anode were compared in two-chamber MFCs. Results showed that the maximum power density of PANI and PAOA MFC could reach 27.4 mW/m(2) and 23.8 mW/m(2), comparing with unmodified MFC, increased by 35% and 18% separately. Low temperature caused greatly decrease of the maximum voltage by 70% and reduced the sorts of bacteria on anodes in the three MFCs. Anode biofilm analysis showed different bacteria enrichment: a larger mount of bacteria and higher biodiversity were found on the two modified anodes than on the unmodified one. For PANI anode, the two predominant bacteria were phylogenetically closely related to Hippea maritima and an uncultured clone MEC_Bicarb_Ac-008; for PAOA, Clostridiales showed more enrichment. Compare PAOA with PANI, the former introduced phenolic hydroxyl group by copolymerization o-aminophenol with aniline, which led to a different microbial community and the mechanism of group effect was proposed. Copyright © 2011 Elsevier B.V. All rights reserved.

Acid-Base Chemistry According to Robert Boyle: Chemical Reactions in Words as well as Symbols

ERIC Educational Resources Information Center

Goodney, David E.

2006-01-01

Examples of acid-base reactions from Robert Boyle's "The Sceptical Chemist" are used to illustrate the rich information content of chemical equations. Boyle required lengthy passages of florid language to describe the same reaction that can be done quite simply with a chemical equation. Reading or hearing the words, however, enriches the student's…

Selective Enrichment and Direct Analysis of Protein S-Palmitoylation Sites.

PubMed

Thinon, Emmanuelle; Fernandez, Joseph P; Molina, Henrik; Hang, Howard C

2018-05-04

S-Fatty-acylation is the covalent attachment of long chain fatty acids, predominately palmitate (C16:0, S-palmitoylation), to cysteine (Cys) residues via a thioester linkage on proteins. This post-translational and reversible lipid modification regulates protein function and localization in eukaryotes and is important in mammalian physiology and human diseases. While chemical labeling methods have improved the detection and enrichment of S-fatty-acylated proteins, mapping sites of modification and characterizing the endogenously attached fatty acids are still challenging. Here, we describe the integration and optimization of fatty acid chemical reporter labeling with hydroxylamine-mediated enrichment of S-fatty-acylated proteins and direct tagging of modified Cys residues to selectively map lipid modification sites. This afforded improved enrichment and direct identification of many protein S-fatty-acylation sites compared to previously described methods. Notably, we directly identified the S-fatty-acylation sites of IFITM3, an important interferon-stimulated inhibitor of virus entry, and we further demonstrated that the highly conserved Cys residues are primarily modified by palmitic acid. The methods described here should facilitate the direct analysis of protein S-fatty-acylation sites and their endogenously attached fatty acids in diverse cell types and activation states important for mammalian physiology and diseases.

Areally Extensive Surface Bedrock Exposures on Mars: Many Are Clastic Rocks, Not Lavas

NASA Astrophysics Data System (ADS)

Rogers, A. Deanne; Warner, Nicholas H.; Golombek, Matthew P.; Head, James W.; Cowart, Justin C.

2018-02-01

Areally extensive exposures of intact olivine/pyroxene-enriched rock, as well as feldspar-enriched rock, are found in isolated locations throughout the Martian highlands. The petrogenetic origin(s) of these rock units are not well understood, but some previous studies favored an effusive volcanic origin partly on the basis of distinctive composition and relatively high thermal inertia. Here we show that the regolith development, crater retention, and morphological characteristics for many of these "bedrock plains" are not consistent with competent lavas and reinterpret the high thermal inertia orbital signatures to represent friable materials that are more easily kept free of comminution products through eolian activity. Candidate origins include pyroclastic rocks, impact-generated materials, or detrital sedimentary rocks. Olivine/pyroxene enrichments in bedrock plains relative to surrounding materials could have potentially formed through deflation and preferential removal of plagioclase.

Laboratory mouse housing conditions can be improved using common environmental enrichment without compromising data.

PubMed

André, Viola; Gau, Christine; Scheideler, Angelika; Aguilar-Pimentel, Juan A; Amarie, Oana V; Becker, Lore; Garrett, Lillian; Hans, Wolfgang; Hölter, Sabine M; Janik, Dirk; Moreth, Kristin; Neff, Frauke; Östereicher, Manuela; Racz, Ildiko; Rathkolb, Birgit; Rozman, Jan; Bekeredjian, Raffi; Graw, Jochen; Klingenspor, Martin; Klopstock, Thomas; Ollert, Markus; Schmidt-Weber, Carsten; Wolf, Eckhard; Wurst, Wolfgang; Gailus-Durner, Valérie; Brielmeier, Markus; Fuchs, Helmut; Hrabé de Angelis, Martin

2018-04-01

Animal welfare requires the adequate housing of animals to ensure health and well-being. The application of environmental enrichment is a way to improve the well-being of laboratory animals. However, it is important to know whether these enrichment items can be incorporated in experimental mouse husbandry without creating a divide between past and future experimental results. Previous small-scale studies have been inconsistent throughout the literature, and it is not yet completely understood whether and how enrichment might endanger comparability of results of scientific experiments. Here, we measured the effect on means and variability of 164 physiological parameters in 3 conditions: with nesting material with or without a shelter, comparing these 2 conditions to a "barren" regime without any enrichments. We studied a total of 360 mice from each of 2 mouse strains (C57BL/6NTac and DBA/2NCrl) and both sexes for each of the 3 conditions. Our study indicates that enrichment affects the mean values of some of the 164 parameters with no consistent effects on variability. However, the influence of enrichment appears negligible compared to the effects of other influencing factors. Therefore, nesting material and shelters may be used to improve animal welfare without impairment of experimental outcome or loss of comparability to previous data collected under barren housing conditions.

[Preparation of molecularly imprinted polypyrrole/Fe3O4 composite material and its application in recognition of tryptophan enantiomers].

PubMed

Chen, Zhidong; Shan, Xueling; Kong, Yong

2012-04-01

Ferrosoferric oxide (Fe(3)O(4)) magnetic material was first synthesized, and then the in-situ chemical polymerization of pyrrole was carried out on the surface of Fe(3)O(4) by using pyrole and L-tryptophan (L-Trp) as the functional monomer and templates, respectively. As a result, molecularly imprinted polypyrrole/Fe(3)O(4) composite material was obtained. This composite material was separated from the solution because of its magnetic property. Polypyrrole in the composite was overoxidized in 1 mol/L NaOH solution by applying a potential of 1.0 V, and thus L-Trp templates were de-deoped from the composite. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical methods were employed to characterize the composite. The solution containing L- or D-Trp was pumped through a porous ceramic tube packed with the composite, separately. High performance liquid chromatography (HPLC) was adopted for the detection of L- or D-Trp in the eluate, and the results indicated that the enrichment ability of the composite for L-Trp was almost 2 times that of D-Trp. Therefore, the electro-magnetic composite material has potential applications as chromatographic stationary phase for chiral recognition.

Mineralogical and geochemical characterization of weathering profiles developed on mylonites in the Fodjomekwet-Fotouni section of the Cameroon Shear Zone (CSZ), West Cameroon

NASA Astrophysics Data System (ADS)

Tematio, P.; Tchaptchet, W. T.; Nguetnkam, J. P.; Mbog, M. B.; Yongue Fouateu, R.

2017-07-01

The mineralogical and geochemical investigation of mylonitic weathering profiles in Fodjomekwet-Fotouni was done to better trace the occurrence of minerals and chemical elements in this area. Four representative soil profiles were identified in two geomorphological units (upland and lowland) differentiating three weathering products (organo-mineral, mineral and weathered materials). Weathering of these mylonites led to some minerals association such as vermiculite, kaolinite, goethite, smectite, halloysite, phlogopite and gibbsite. The minerals in a decreasing order of abundance are: quartz (24.2%-54.8%); kaolinite (8.4%-36.0%); phlogopite (5.5%-21.9%); goethite (7.8%-16.1%); vermiculite (6.7%-15.7%); smectite (10.2%-11.9%); gibbsite (9.0%-11.8%) and halloysite (5.6%-11.5%) respectively. Patterns of chemical elements allow highlighting three behaviors (enriched elements, depleted elements and elements with complex behavior), depending on the landscape position of the profiles. In the upland weathering products, K, Cr and REEs are enriched; Ca, Mg, Na, Mn, Rb, S and Sr are depleted while Si, Al, Fe, Ti, Ba, Co, Cu, Ga, Mo, Nb, Ni, Pb, Sc, V, Y, Zn and Zr portray a complex behavior. Contrarily, the lowland weathering profiles enriched elements are Fe, Ti, Co, Cr, Cu, V, Zr, Pr, Sm, Tb, Dy, Er and Yb; while depleted elements are Ca, Mg, K, Na, Mn, Ba, Ga, S, Sr, Y, Zn, La, Ce and Nd; and Si, Al, Mo, Nb, Ni, Pb, Rb, Sc evidenced complex behaviors. In all the studied weathering products, the REEs fractionation was also noticeable with a landscape-position dependency, showing light REEs (LREEs) enrichment in the upland areas and heavy REEs (HREEs) in lowland areas. SiO2, Al2O3 and Fe2O3 are positively correlated with most of the traces and REEs (Co, Cu, Nb, Ni, Mo, Pb, Sc, V, Zn, Zr, La, Ce, Sm, Tb, Dy, Er, Yb), pointing to the fact that they may be incorporated into newly formed clay minerals and oxides. Ba, Cr, Ga, Rb, S, Sr, Y, Pr and Nd behave like alkalis and alkaline earths, and are thus highly mobile during weathering.

Two-Dimensional MoS2-Based Zwitterionic Hydrophilic Interaction Liquid Chromatography Material for the Specific Enrichment of Glycopeptides.

PubMed

Xia, Chaoshuang; Jiao, Fenglong; Gao, Fangyuan; Wang, Heping; Lv, Yayao; Shen, Yehua; Zhang, Yangjun; Qian, Xiaohong

2018-06-05

Mass spectrometry (MS)-based glycoproteomics research requires highly efficient sample preparation to eliminate interference from non-glycopeptides and to improve the efficiency of glycopeptide detection. In this work, a novel MoS 2 /Au-NP (gold nanoparticle)-L-cysteine nanocomposite was prepared for glycopeptide enrichment. The two-dimensional (2D) structured MoS 2 nanosheets served as a matrix that could provide a large surface area for immobilizing hydrophilic groups (such as L-cysteine) with low steric hindrance between the materials and the glycopeptides. As a result, the novel nanomaterial possessed an excellent ability to capture glycopeptides. Compared to commercial zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) materials, the novel nanomaterials exhibited excellent enrichment performance with ultrahigh selectivity and sensitivity (approximately 10 fmol), high binding capacity (120 mg g -1 ), high enrichment recovery (more than 93%), satisfying batch-to-batch reproducibility, and good universality for glycopeptide enrichment. In addition, its outstanding specificity and efficiency for glycopeptide enrichment was confirmed by the detection of glycopeptides from an human serum immunoglobulin G (IgG) tryptic digest in quantities as low as a 1:1250 molar ratio of IgG tryptic digest to bovine serum albumin tryptic digest. The novel nanocomposites were further used for the analysis of complex samples, and 1920 glycopeptide backbones from 775 glycoproteins were identified in three replicate analyses of 50 μg of proteins extracted from HeLa cell exosomes. The resulting highly informative mass spectra indicated that this multifunctional nanomaterial-based enrichment method could be used as a promising tool for the in-depth and comprehensive characterization of glycoproteomes in MS-based glycoproteomics.

Iron mineralogy and uranium-binding environment in the rhizosphere of a wetland soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaplan, Daniel I.; Kukkadapu, Ravi; Seaman, John C.

Wetlands mitigate the migration of groundwater contaminants through the creation of biogeochemical gradients that enhance multiple contaminant-binding processes. Our hypothesis was that wetland plants not only contribute organic carbon, produce strong redox gradients, and elevate microbial populations to soils, but together these conditions also promote the formation of Fe (oxyhydr)oxides within the plant rhizosphere that may also contribute to contaminant immobilization. Mineralogy and U binding environments of the rhizosphere (plant-impacted soil zone) were evaluated in samples collected from contaminated and non-contaminated areas of a wetland on the Savannah River Site in South Carolina. Based on Mossbauer spectroscopy, rhizosphere soil collectedmore » from the field study site was greatly enriched with poorly crystalline nanoparticulate Fe-oxide/ferrihydrite-like materials and nano-goethite (<15-nm). X-ray computed tomography or various microscopy techniques showed that root plaques, tens-of microns thick, were consisted of highly oriented nanoparticles in an orientation suggestive that the roots were involved in the Fe-nanoparticle formation. Because of detection limits, SEM/EDS could not confirm whether U was enriched in the rhizosphere but did demonstrate that U was enriched on root plaques. Uranium in the plaques was always found in association with P and frequently with Fe. Together these findings suggest that plants may not only alter soil microbial and chemical conditions, but also mineralogical conditions that may be conducive to aqueous contaminant immobilization in wetlands.« less

Computer-Enriched Instruction (CEI) Is Better for Preview Material Instead of Review Material: An Example of a Biostatistics Chapter, the Central Limit Theorem

ERIC Educational Resources Information Center

See, Lai-Chu; Huang, Yu-Hsun; Chang, Yi-Hu; Chiu, Yeo-Ju; Chen, Yi-Fen; Napper, Vicki S.

2010-01-01

This study examines the timing using computer-enriched instruction (CEI), before or after a traditional lecture to determine cross-over effect, period effect, and learning effect arising from sequencing of instruction. A 2 x 2 cross-over design was used with CEI to teach central limit theorem (CLT). Two sequences of graduate students in nursing…

Uranium enrichment in lacustrine oil source rocks of the Chang 7 member of the Yanchang Formation, Erdos Basin, China

NASA Astrophysics Data System (ADS)

Yang, Hua; Zhang, Wenzheng; Wu, Kai; Li, Shanpeng; Peng, Ping'an; Qin, Yan

2010-09-01

The oil source rocks of the Chang 7 member of the Yanchang Formation in the Erdos Basin were deposited during maximum lake extension during the Late Triassic and show a remarkable positive uranium anomaly, with an average uranium content as high as 51.1 μg/g. Uranium is enriched together with organic matter and elements such as Fe, S, Cu, V and Mo in the rocks. The detailed biological markers determined in the Chang 7 member indicate that the lake water column was oxidizing during deposition of the Chang 7 member. However, redox indicators for sediments such as S 2- content, V/Sc and V/(V + Ni) ratios demonstrate that it was a typical anoxic diagenetic setting. The contrasted redox conditions between the water column and the sediment with a very high content of organic matter provided favorable physical and chemical conditions for syngenetic uranium enrichment in the oil source rocks of the Chang 7 member. Possible uranium sources may be the extensive U-rich volcanic ash that resulted from contemporaneous volcanic eruption and uranium material transported by hydrothermal conduits into the basin. The uranium from terrestrial clastics was unlike because uranium concentration was not higher in the margin area of basin where the terrestrial material input was high. As indicated by correlative analysis, the oil source rocks of the Chang 7 member show high gamma-ray values for radioactive well log data that reflect a positive uranium anomaly and are characterized by high resistance, low electric potential and low density. As a result, well log data can be used to identify positive uranium anomalies and spatial distribution of the oil source rocks in the Erdos Basin. The estimation of the total uranium reserves in the Chang 7 member attain 0.8 × 10 8 t.

[Comparative studies of methods of salmonella enrichment (author's transl)].

PubMed

Pietzsch, O; Kretschmer, F J; Bulling, E

1975-07-01

Eight different methods of salmonella enrichment were compared in two series of experiments involving 100 samples of whole-egg powder and 80 samples of frozen whole liquid egg, respectively. 66 out of a total of 100 samples of whole-egg powder had been artificially infected with varying numbers of S. typhi-murium; 60 out of 80 samples of frozen whole liquid egg were found to be naturally infected with various salmonella species. 3 of the 8 methods (Table 1) were compared within an international collaborative study with 14 laboratories in 11 countries participating. A reduction of the pre-enrichment period from 18 to 6 hours and of volumes used in pre-enrichment and selective enrichment from 10 and 100 ml, respectively to 1 and 10 ml, respectively were found to have adverse influence upon the result of isolations, in particular in the case of weakly infected samples. In contrast, extended incubation over 48 hours as well as preparation of two sub-cultures on solid selective media following incubation of enrichment cultures over 18-24 hours and 42-48 hours, respectively always resulted in a certain increase of salmonella yield which, however, exhibited gradual differences for the individual methods examined. Preparation of a 2nd sub-culture meant, in particular, a decisive improvement of the result of isolations from artificially infected samples if selenite-cystine enrichment volumes were 10 and 100 ml, respectively. The best results could be obtained by means of the following methods of enrichment: Pre-enrichment of material in buffered peptone water at 37 degrees C over 18 hours; pipetting of 10 ml inoculated and incubated pre-enriched material into 100 ml selenite-cystine or tetrathionate enrichment medium according to MULLER-KAUFFMANN; onward incubation of the enrichment culture at 43 degrees C over 48 hours; and preparation of sub-cultures on solid selective media after 24 and 48 hours. The method using tetrathionate enrichment medium was found to be most expensive, results, however, were the most consistent ones.

10 CFR Appendix B to Part 110 - Illustrative List of Gas Centrifuge Enrichment Plant Components Under NRC's Export Licensing...

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 2 2011-01-01 2011-01-01 false Illustrative List of Gas Centrifuge Enrichment Plant... 110—Illustrative List of Gas Centrifuge Enrichment Plant Components Under NRC's Export Licensing...×109 N/m2 (67,000 lb/in.2 ) or more. (c) Filamentary materials suitable for use in composite structures...

Hydrothermal signature in the axial-sediments from the Carlsberg Ridge in the northwest Indian Ocean

NASA Astrophysics Data System (ADS)

Yu, Zenghui; Li, Huaiming; Li, Mengxing; Zhai, Shikui

2018-04-01

30 sediments grabbed from 24 sites between the equator and 10°N along the Carlsberg Ridge (CR) in the northwest Indian Ocean has been analyzed for bulk chemical compositions. Hydrothermal components in the sediments are identified and characterized. They mainly occur at 6.3°N as sulfide debris and at 3.6°N as both sulfide and high temperature water-rock interaction products. The enrichment of chalcophile elements such as Zn, Cu, Pb and the depletion of alkalis metals such as K and Rb are the typical features of hydrothermal components. High U/Fe, low (Nd/Yb)N and negative Ce anomaly infer the uptake of seawater in the hydrothermal deposits by oxidizing after deposition. However, the general enrichment of Mn in hydrothermal plumed-derived materials is not found in the sediments, which may indicate the limited diffusion of fluids or plumes, at least in the direction along the Carlsberg spreading center. The hydrothermal components show their similarity to the hydrothermal deposits from the Indian Ocean Ridge. At 3.6°N ultramafic rocks or gabbroic intrusions, may be involved in the hydrothermal system.

Valorisation of waste ilmenite mud in the manufacture of sulphur polymer cement.

PubMed

Contreras, Manuel; Gázquez, Manuel Jesús; García-Díaz, Irene; Alguacil, Francisco J; López, Félix A; Bolívar, Juan Pedro

2013-10-15

This paper reports the preparation of sulphur polymer cements (SPCs) incorporating waste ilmenite mud for use in concrete construction works. The ilmenite mud raw material and the mud-containing SPCs (IMC-SPCs) were characterised physico-chemically and radiologically. The optimal IMC-SPC mixture had a sulphur/mud ratio (w/w) of 1.05 (mud dose 20 wt%); this cement showed the greatest compressive strength (64 MPa) and the lowest water absorption coefficient (0.4 g cm(-2) at 28 days). Since ilmenite mud is enriched in natural radionuclides, such as radium isotopes (2.0·10(3) Bq kg(-1)(228)Ra and 5.0·10(2) Bq kg(-1)(226)Ra), the IMC-SPCs were subjected to leaching experiments, which showed their environmental impact to be negligible. The activity concentration indices for the different radionuclides in the IMC-SPCs containing 10% and 20% ilmenite mud met the demands of international standards for materials used in the construction of non-residential buildings. Copyright © 2013 Elsevier Ltd. All rights reserved.

Self-Assembling Amphiphilic Molecules: A Possible Relationship Between Interstellar Chemistry and Meteoritic Organics

NASA Technical Reports Server (NTRS)

Sandford, Scott A.; Dworkin, Jason P.; Deamer, David W.; Allamandola, Louis J.; DeVincenzi, Donald (Technical Monitor)

2001-01-01

Interstellar gas and dust comprise the primary material from which the solar system formed. Evidence that some of this material was organic in nature and survived incorporation into the protosolar nebula is provided by the presence of deuterium-enriched organics in meteorites and interplanetary dust particles. Once the inner planets had sufficiently cooled, late accretionary infall of meteoroids and cosmic dust must have seeded them with some of these complex organic compounds. Delivery of such extraterrestrial compounds may have contributed to the organic inventory necessary for the origin of life. Interstellar ices, the building blocks of comets, tie up a large fraction of the biogenic elements available in molecular clouds. In our efforts to understand their synthesis, chemical composition, and physical properties, we report here that a complex mixture of molecules is produced by ultraviolet (UV) photolysis of realistic, interstellar ice analogs, and that some of the components have properties relevant to the origin of life, including the ability to self-assemble into vesicular structures.

Interaction between a pulsating jet and a surrounding disk wind. A hydrodynamical perspective

NASA Astrophysics Data System (ADS)

Tabone, B.; Raga, A.; Cabrit, S.; Pineau des Forêts, G.

2018-06-01

Context. The molecular richness of fast protostellar jets within 20-100 au of their source, despite strong ultraviolet irradiation, remains a challenge for the models investigated so far. Aim.We aim to investigate the effect of interaction between a time-variable jet and a surrounding steady disk wind, to assess the possibility of jet chemical enrichement by the wind, and the characteristic signatures of such a configuration. Methods: We have constructed an analytic model of a jet bow shock driven into a surrounding slower disk wind in the thin shell approximation. The refilling of the post bow shock cavity from below by the disk wind is also studied. An extension of the model to the case of two or more successive internal working surfaces (IWS) is made. We then compared this analytic model with numerical simulations with and without a surrounding disk wind. Results: We find that at early times (of order the variability period), jet bow shocks travel in refilled pristine disk wind material, before interacting with the cocoon of older bow shocks. This opens the possibility of bow shock chemical enrichment (if the disk wind is molecular and dusty) and of probing the unperturbed disk wind structure near the jet base. Several distinctive signatures of the presence of a surrounding disk wind are identified, in the bow shock morphology and kinematics. Numerical simulations validate our analytical approach and further show that at large scale, the passage of many jet IWS inside a disk wind produces a stationary V-shaped cavity, closing down onto the axis at a finite distance from the source.

A chemical confirmation of the faint Boötes II dwarf spheroidal galaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koch, Andreas; Rich, R. Michael, E-mail: akoch@lsw.uni-heidelberg.de

2014-10-10

We present a chemical abundance study of the brightest confirmed member star of the ultra-faint dwarf galaxy Boötes II from Keck/HIRES high-resolution spectroscopy at moderate signal-to-noise ratios. At [Fe/H] = –2.93 ± 0.03(stat.) ± 0.17(sys.), this star chemically resembles metal-poor halo field stars and the signatures of other faint dwarf spheroidal galaxies at the same metallicities in that it shows enhanced [α/Fe] ratios, Solar Fe-peak element abundances, and low upper limits on the neutron-capture element Ba. Moreover, this star shows no chemical peculiarities in any of the eight elements we were able to measure. This implies that the chemical outliersmore » found in other systems remain outliers pertaining to the unusual enrichment histories of the respective environments, while Boo II appears to have experienced an enrichment history typical of its very low mass. We also re-calibrated previous measurements of the galaxy's metallicity from the calcium triplet (CaT) and find a much lower value than reported before. The resulting broad metallicity spread, in excess of one dex, the very metal-poor mean, and the chemical abundance patterns of the present star imply that Boötes II is a low-mass, old, metal-poor dwarf galaxy and not an overdensity associated with the Sagittarius Stream as has been previously suggested based on its sky position and kinematics. The low, mean CaT metallicity of –2.7 dex falls right on the luminosity-metallicity relation delineated over four orders of magnitude from the more luminous to the faintest galaxies. Thus Boötes II's chemical enrichment appears representative of the galaxy's original mass, while tidal stripping and other mass loss mechanisms were probably not significant as for other low-mass satellites.« less

Rare-earth element fractionation in uranium ore and its U(VI) alteration minerals

DOE PAGES

Balboni, Enrica; Spano, T; Cook, N; ...

2017-10-20

We developed a cation exchange chromatography method employing sulfonated polysterene cation resin (DOWEX AG50-X8) in order to separate rare-earth elements (REEs) from uranium-rich materials. The chemical separation scheme is designed to reduce matrix effects and consequently yield enhanced ionization efficiencies for concentration determinations of REEs without significant fractionation using solution mode-inductively coupled plasma mass spectrometry (ICP-MS) analysis. This method was then applied to determine REE abundances in four uraninite (ideally UO 2) samples and their associated U(VI) alteration minerals. In three of the samples analyzed, the concentration of REEs for primary uraninite are higher than those for their corresponding secondarymore » uranium alteration phases. The results for U(VI) alteration minerals of two samples indicate enrichment of the light REEs (LREEs) over the heavy REEs (HREEs). This differential mobilization is attributed to differences in the mineralogical composition of the U(VI) alteration. There is a lack of fractionation of the LREEs in the uraninite alteration rind that is composed of U(VI) minerals containing Ca 2+ as the interlayer cation (uranophane and bequerelite); contrarily, U(VI) alteration minerals containing K + and Pb 2+ as interlayer cations (fourmarierite, dumontite) indicate fractionation (enrichment) of the LREEs. Our results have implications for nuclear forensic analyses since a comparison is reported between the REE abundances for the CUP-2 (processed uranium ore) certified reference material and previously determined values for uranium ore concentrate (UOC) produced from the same U deposit (Blind River/Elliott Lake, Canada). UOCs represent the most common form of interdicted nuclear material and consequently is material frequently targeted for forensic analysis. The comparison reveals similar chondrite normalized REE signatures but variable absolute abundances. Based on the results reported here, the latter may be attributed to the differing REE abundances between primary ore and associated alteration phases, and/or is related to varying fabrication processes adopted during production of UOC.« less

Rare-earth element fractionation in uranium ore and its U(VI) alteration minerals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balboni, Enrica; Spano, T; Cook, N

We developed a cation exchange chromatography method employing sulfonated polysterene cation resin (DOWEX AG50-X8) in order to separate rare-earth elements (REEs) from uranium-rich materials. The chemical separation scheme is designed to reduce matrix effects and consequently yield enhanced ionization efficiencies for concentration determinations of REEs without significant fractionation using solution mode-inductively coupled plasma mass spectrometry (ICP-MS) analysis. This method was then applied to determine REE abundances in four uraninite (ideally UO 2) samples and their associated U(VI) alteration minerals. In three of the samples analyzed, the concentration of REEs for primary uraninite are higher than those for their corresponding secondarymore » uranium alteration phases. The results for U(VI) alteration minerals of two samples indicate enrichment of the light REEs (LREEs) over the heavy REEs (HREEs). This differential mobilization is attributed to differences in the mineralogical composition of the U(VI) alteration. There is a lack of fractionation of the LREEs in the uraninite alteration rind that is composed of U(VI) minerals containing Ca 2+ as the interlayer cation (uranophane and bequerelite); contrarily, U(VI) alteration minerals containing K + and Pb 2+ as interlayer cations (fourmarierite, dumontite) indicate fractionation (enrichment) of the LREEs. Our results have implications for nuclear forensic analyses since a comparison is reported between the REE abundances for the CUP-2 (processed uranium ore) certified reference material and previously determined values for uranium ore concentrate (UOC) produced from the same U deposit (Blind River/Elliott Lake, Canada). UOCs represent the most common form of interdicted nuclear material and consequently is material frequently targeted for forensic analysis. The comparison reveals similar chondrite normalized REE signatures but variable absolute abundances. Based on the results reported here, the latter may be attributed to the differing REE abundances between primary ore and associated alteration phases, and/or is related to varying fabrication processes adopted during production of UOC.« less

Primary marine aerosol physical flux and chemical composition during a nutrient enrichment experiment in mesocosms in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Schwier, Allison N.; Sellegri, Karine; Mas, Sébastien; Charrière, Bruno; Pey, Jorge; Rose, Clémence; Temime-Roussel, Brice; Jaffrezo, Jean-Luc; Parin, David; Picard, David; Ribeiro, Mickael; Roberts, Greg; Sempéré, Richard; Marchand, Nicolas; D'Anna, Barbara

2017-12-01

While primary marine aerosol (PMA) is an important part of global aerosol total emissions, its chemical composition and physical flux as a function of the biogeochemical properties of the seawater still remain highly uncharacterized due to the multiplicity of physical, chemical and biological parameters that are involved in the emission process. Here, two nutrient-enriched mesocosms and one control mesocosm, both filled with Mediterranean seawater, were studied over a 3-week period. PMA generated from the mesocosm waters were characterized in term of chemical composition, size distribution and size-segregated cloud condensation nuclei (CCN), as a function of the seawater chlorophyll a (Chl a) concentration, pigment composition, virus and bacteria abundances. The aerosol number size distribution flux was primarily affected by the seawater temperature and did not vary significantly from one mesocosm to the other. The aerosol number size distribution flux was primarily affected by the seawater temperature and did not vary significantly from one mesocosm to the other. Particle number and CCN aerosol fluxes increase by a factor of 2 when the temperature increases from 22 to 32 °C, for all particle submicron sizes. This effect, rarely observed in previous studies, could be specific to oligotrophic waters and/or to this temperature range. In all mesocosms (enriched and control mesocosms), we detected an enrichment of calcium (+500 %) and a deficit in chloride (-36 %) in the submicron PMA mass compared to the literature inorganic composition of the seawater. There are indications that the chloride deficit and calcium enrichment are linked to biological processes, as they are found to be stronger in the enriched mesocosms. This implies a non-linear transfer function between the seawater composition and PMA composition, with complex processes taking place at the interface during the bubble bursting. We found that the artificial phytoplankton bloom did not affect the CCN activation diameter (Dp, 50, average = 59.85±3.52 nm and Dp,50,average = 93.42±5.14 nm for supersaturations of 0.30 and 0.15 % respectively) or the organic fraction of the submicron PMA (average organic to total mass = 0.31±0.07) compared to the control mesocosm. Contrary to previous observations in natural bloom mesocosm experiments, the correlation between the particle organic fraction and the seawater Chl a was poor, indicating that Chl a is likely not a straightforward proxy for predicting, on a daily scale, PMA organic fraction in models for all types of sea and ocean waters. Instead, the organic fraction of the Aitken mode particles were more significantly linked to heterotrophic flagellates, viruses and dissolved organic carbon (DOC). We stress that different conclusions may be obtained in natural (non-enriched) or non-oligotrophic systems.

Stream-sediment geochemistry in mining-impacted streams: Prichard, Eagle, and Beaver creeks, northern Coeur d'Alene Mining District, northern Idaho

USGS Publications Warehouse

Box, Stephen E.; Wallis, John C.; Briggs, Paul H.; Brown, Zoe Ann

2005-01-01

This report presents the results of one aspect of an integrated watershed-characterization study that was undertaken to assess the impacts of historical mining and milling of silver-lead-zinc ores on water and sediment composition and on aquatic biota in streams draining the northern part of the Coeur d?Alene Mining District in northern Idaho. We present the results of chemical analyses of 62 samples of streambed sediment, 19 samples of suspended sediment, 23 samples of streambank soil, and 29 samples of mine- and mill-related artificial- fill material collected from the drainages of Prichard, Eagle, and Beaver Creeks, all tributaries to the North Fork of the Coeur d?Alene River. All samples were sieved into three grain-size fractions (<0.063, 0.063?0.25, and 0.25?1.0 mm) and analyzed for 40 elements after four-acid digestion by inductively coupled plasma atomic-emission spectrometry and for mercury by continuous- flow cold-vapor atomic-absorption spectrometry in the U.S. Geological Survey laboratory in Denver, Colo. Historical mining of silver-lead-zinc ores in the headwater reaches of the Prichard Creek, Eagle Creek, and Beaver Creek drainages has resulted in enrichments of lead, zinc, mercury, arsenic, cadmium, silver, copper, cobalt, and, to a lesser extent, iron and manganese in streambed sediment. Using samples collected from the relatively unimpacted West Fork of Eagle Creek as representative of background compositions, streambed sediment in the vicinity of the mines and millsites has Pb and Zn contents of 20 to 100 times background values, decreasing to 2 to 5 times background values at the mouth of the each stream, 15 to 20 km downstream. Lesser enrichments (<10 times background values) of mercury and arsenic also are generally associated with, and decrease downstream from, historical silver-lead-zinc mining in the drainages. However, enrichments of arsenic and, to a lesser extent, mercury also are areally associated with the lode gold deposits along Prichard Creek near Murray, which were not studied here. Metal contents in samples of unfractionated suspended sediment collected during a high-flow event in April 2000 are generally similar to, but slightly higher than, those in the fine (<0.063- mm grain size) fraction of streambed sediment from the same sampling site. Although metal enrichment in streambed sediment typically begins adjacent to the mine portals and their associated mine-waste rock dumps, volumetrically larger inputs of metal-enriched materials were contributed by the ore-concentration millsites and their associated, more finely ground, more metal rich mill-tailings impoundments.

The Effect of Edible Coating Enriched With Kaffir Lime Leaf Essential Oil (Citrus hystrix DC) on Beef Sausage Quality During Frozen Storage (-18°±2°C)

NASA Astrophysics Data System (ADS)

Utami, R.; Kawiji; Khasanah, L. U.; Solikhah, R.

2018-03-01

The aim of this study was to determine the effect of edible coating enriched with kaffir lime (Citrus hystrix DC) leaves essential oil at various concentration on beef sausage quality during frozen storage (-18°±2°C). The concentration of kaffir lime leaves essential oil enriched in edible coating were varied at 0%; 0.2%; 1.4%. Microbiological, physical and chemical characteristics (TPC, color, TBA, TVB, and pH) were investigated at 0, 1, 2, 3, and 4 months of storage. The result showed that edible coating with the addition of kaffir lime leaves essential oils decreased the microbial growth, TVB value, and TBA value of beef sausage. The color and pH of samples can be stabilized during storage. The selected kaffir lime leaves essential oil concentrations based on microbial, physical, and chemical characteristics of beef sausages during frozen storage at -18°C was 0.2%.

A status of progress for the Laser Isotope Separation (LIS) process

NASA Technical Reports Server (NTRS)

Delionback, L. M.

1976-01-01

An overview of the Laser Isotope Separation (LIS) methodology is given together with illustrations showing a simplified version of the LIS technique, an example of the two-photon photoionization category, and a diagram depicting how the energy levels of various isotope influence the LIS process. Applications were proposed for the LIS system which, in addition to enriching uranium, could in themselves develop into programs of tremendous scope and breadth. These include the treatment of radioactive wastes from light-water nuclear reactors, enriching the deuterium isotope to make heavy-water, and enriching the light isotopes of such elements as titanium for aerospace weight-reducing programs. Economic comparisons of the LIS methodology with the current method of gaseous diffusion indicate an overwhelming advantage; the laser process promises to be 1000 times more efficient. The technique could also be utilized in chemical reactions with the tuned laser serving as a universal catalyst to determine the speed and direction of a chemical reaction.

Facile preparation of magnetic graphene double-sided mesoporous composites for the selective enrichment and analysis of endogenous peptides.

PubMed

Yin, Peng; Sun, Nianrong; Deng, Chunhui; Li, Yan; Zhang, Xiangmin; Yang, Pengyuan

2013-08-01

In this work, magnetic graphene double-sided mesoporous nanocomposites (mag-graphene@mSiO₂) were synthesized by coating a layer of mesoporous silica materials on each side of magnetic grapheme. The surfactant (CTAB) mediated sol-gel coating was performed using tetraethyl orthosilicate as the silica source. The as-made magnetic graphene double-sided mesoporous silica composites were treated with high-temperature calcination to remove the hydroxyl on the surface. The novel double-sided materials possess high surface area (167.8 cm²/g) and large pore volume (0.2 cm³/g). The highly open pore structure presents uniform pore size (3.2 nm) and structural stability. The hydrophobic interior pore walls could ensure an efficient adsorption of target molecules through hydrophobic-hydrophobic interaction. At the same time, the magnetic Fe₃O₄ particles on both sides of the materials could simplify the process of enrichment, which plays an important role in the treatment of complex biological samples. The magnetic graphene double-sided nanocomposites were successfully applied to size-selective and specific enrichment of peptides in standard peptide mixtures, protein digest solutions, and human urine samples. Finally, the novel material was applied to selective enrichment of endogenous peptides in mouse brain tissue. The enriched endogenous peptides were then analyzed by LC-MS/MS, and 409 endogenous peptides were detected and identified. The results demonstrate that the as-made mag-graphene@mSiO₂ have powerful potential for peptidome research. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal enrichments in solid bitumens: A review

NASA Astrophysics Data System (ADS)

Parnell, J.

1988-07-01

The association of oils and solid bitumens with ore deposits is widely recorded. The oils and bitumens may actually be enriched with metals. Unlike oils, metal enrichments within bitumens do not reflect the role of petroleum as a transporting agent for metals. By contrast, they may be a result of the reduction of metal ions on contact with bitumen, and may reach levels so high that ore mineral inclusions are precipitated. Metal determinations of British bitumens suggest that new metal anomalies can be detected by this approach, that some metal anomalies within bitumens may be related to ore mineralization, and that bitumens from different sources may be distinguished by their metal contents. The potential use of bitumen distribution and/or metal enrichment within bitumen for ore exploration is dependent on the metal concerned, and in particular whether the metal is transported by association with organic materials or reduced in the presence of organic materials.

Interstellar and Solar Nebula Materials in Cometary Dust

NASA Technical Reports Server (NTRS)

Messenger, Scott; Nakamura-Messenger, Keiko; Keller, Lindsay; Nguyen, Ann; Clemett, Simon

2017-01-01

Laboratory studies of cometary dust collected in the stratosphere and returned from comet 81P/Wild 2 by the Stardust spacecraft have revealed ancient interstellar grains and molecular cloud organic matter that record a range of astrophysical processes and the first steps of planetary formation. Presolar materials are rarer meteorites owing to high temperature processing in the solar nebula and hydrothermal alteration on their asteroidal parent bodies. The greater preservation of presolar materials in comets is attributed to their low accretion temperatures and limited planetary processing. Yet, comets also contain a large complement of high temperature materials from the inner Solar System. Owing to the limited and biased sampling of comets to date, the proportions of interstellar and Solar System materials within them remains highly uncertain. Interstellar materials are identified by coordinated isotopic, mineralogical, and chemical measurements at the scale of individual grains. Chondritic porous interplanetary dust particles (CP IDPs) that likely derive from comets are made up of 0.1 - 10 micron-sized silicates, Fe-Ni-sulfides, oxides, and other phases bound by organic material. As much as 1% of the silicates are interstellar grains that have exotic isotopic compositions imparted by nucleosynthetic processes in their parent stars. Crystalline silicates in CP IDPs dominantly have normal isotopic compositions and probably formed in the Solar System. 81P samples include isotopically normal refractory minerals that resemble Ca-Al rich inclusions and chondrules common in meteorites. The origins of sub-micron amorphous silicates in IDPs are not certain, but at least a few % of them are interstellar grains. The remainder have isotopic compositions consistent with Solar System origins and elemental compositions that are inconsistent with interstellar grain properties, thus favoring formation in the solar nebula [4]. The organic component in comets and primitive meteorites has large enrichments in D/H and N-15/N-14 relative to terrestrial materials. These isotopic signatures are probably due to low temperature chemical processes in cold molecular clouds or the outermost reaches of the protoplanetary disk. The greatest isotopic anomalies are found in sub-micron organic nanoglobules that show chemical signatures of interstellar chemistry. The observation that cometary dust is mostly composed of isotopically normal minerals within isotopically anomalous organic matter is difficult to reconcile with the formation models of each component. The mineral component likely formed in high temperature processes in the inner Solar System, while the organic fraction shows isotopic and chemical signatures of formation near 10 K. Studying more primitive remnants of the Solar System starting materials would help in resolving this paradox. Comets formed across a vast expanse of the outer disk under differing thermal and collisional regimes, and some are likely to be better preserved than others. Finding truly pristine aggregates of presolar materials may require return of a pristine sample of comet nucleus material.

Recycling Seamounts: Implications for Mantle Source Heterogeneities

NASA Astrophysics Data System (ADS)

Madrigal, P.; Gazel, E.

2016-12-01

Isolated seamounts formed away from plate boundaries and/or known hotspot tracks are widely distributed in the Earth's oceanic plates. Despite their pervasiveness, the origin and composition of the magmatic sources that create these seamounts are still unknown. Moreover, as the seamount provinces travel along with the oceanic plate towards subduction trenches these volcanic edifices become subducted materials that are later recycled into the mantle. Using radiogenic isotopes (Sr-Nd-Pb) from present-day non-plume ocean island basalts (OIB) sampled by drilling and dredging as well as by normal processes of accretion to subduction margins, we modeled the isotopic evolution of these enriched reservoirs to assess their role as discrete components contributing to upper mantle heterogeneity. Our evidence suggests that a highly enriched mantle reservoir can originate from OIB-type subducted material that gets incorporated and stirred throughout the upper mantle in a shorter time period ( 200 Ma-500 Ma) than other highly enriched components like ancient subducted oceanic crust (>1 Ga), thought to be the forming agent of the HIMU mantle reservoir endmember. Enriched signatures from intraplate volcanism can be described by mixing of a depleted component like DMM and an enriched reservoir like non-plume related seamounts. Our data suggests that the isotopic evolution in time of a seamount-province type of reservoir can acquire sufficiently enriched compositions to resemble some of the most enriched magmas on Earth. This "fast-forming" (between 200 and 500 Ma) enriched reservoir could also explain some of the enriched signatures commonly present in intraplate and EMORB magmas unrelated to deep mantle plume upwellings.

Deuterium enrichment by selective photo-induced dissociation of an organic carbonyl compound

DOEpatents

Marling, John B.

1981-01-01

A method for producing a deuterium enriched material by photoinduced dissociation which uses as the working material a gas phase photolytically dissociable organic carbonyl compound containing at least one hydrogen atom bonded to an atom which is adjacent to a carbonyl group and consisting of molecules wherein said hydrogen atom is present as deuterium and molecules wherein said hydrogen atom is present as another isotope of hydrogen. The organic carbonyl compound is subjected to intense infrared radiation at a preselected wavelength to selectively excite and thereby induce dissociation of the deuterium containing species to yield a deuterium enriched stable molecular product. Undissociated carbonyl compound, depleted in deuterium, is preferably redeuterated for reuse.

Weighted Feature Significance: A Simple, Interpretable Model of Compound Toxicity Based on the Statistical Enrichment of Structural Features

PubMed Central

Huang, Ruili; Southall, Noel; Xia, Menghang; Cho, Ming-Hsuang; Jadhav, Ajit; Nguyen, Dac-Trung; Inglese, James; Tice, Raymond R.; Austin, Christopher P.

2009-01-01

In support of the U.S. Tox21 program, we have developed a simple and chemically intuitive model we call weighted feature significance (WFS) to predict the toxicological activity of compounds, based on the statistical enrichment of structural features in toxic compounds. We trained and tested the model on the following: (1) data from quantitative high–throughput screening cytotoxicity and caspase activation assays conducted at the National Institutes of Health Chemical Genomics Center, (2) data from Salmonella typhimurium reverse mutagenicity assays conducted by the U.S. National Toxicology Program, and (3) hepatotoxicity data published in the Registry of Toxic Effects of Chemical Substances. Enrichments of structural features in toxic compounds are evaluated for their statistical significance and compiled into a simple additive model of toxicity and then used to score new compounds for potential toxicity. The predictive power of the model for cytotoxicity was validated using an independent set of compounds from the U.S. Environmental Protection Agency tested also at the National Institutes of Health Chemical Genomics Center. We compared the performance of our WFS approach with classical classification methods such as Naive Bayesian clustering and support vector machines. In most test cases, WFS showed similar or slightly better predictive power, especially in the prediction of hepatotoxic compounds, where WFS appeared to have the best performance among the three methods. The new algorithm has the important advantages of simplicity, power, interpretability, and ease of implementation. PMID:19805409

Pakistan’s Nuclear Weapons: Proliferation and Security Issues

DTIC Science & Technology

2009-12-09

Nuclear Terrorism in Pakistan: Sabotage of a Spent Fuel Cask or a Commercial Irradiation Source in Transport ,” in Pakistan’s Nuclear Future, 2008...gave additional urgency to the program. Pakistan produced fissile material for its nuclear weapons using gas-centrifuge-based uranium enrichment...technology, which it mastered by the mid-1980s. Highly-enriched uranium (HEU) is one of two types of fissile material used in nuclear weapons; the other

Enrichment of reactive macerals in coal: its characterization and utilization in coke making

NASA Astrophysics Data System (ADS)

Nag, Debjani; Kopparthi, P.; Dash, P. S.; Saxena, V. K.; Chandra, S.

2018-01-01

Macerals in coal are of different types: reactive and inert. These macerals are differ in their physical and chemical properties. Column flotation method has been used to separate the reactive macerals in a non-coking coal. The enriched coal is then characterized in order to understand the changes in the coking potential by different techniques. It is then used in making of metallurgical coke by proper blending with other coals. Enriched coal enhance the properties of metallurgical coke. This shows a path of utilization of non-coking coal in metallurgical coke making.

Confined-Volume Effect on the Thermal Properties of Encapsulated Phase Change Materials for Thermal Energy Storage.

PubMed

De Castro, Paula F; Ahmed, Adham; Shchukin, Dmitry G

2016-03-18

We have encapsulated the heat exchange material, n-docosane, into polyurethane capsules of different sizes. Decreasing the size of the capsules leads to changes of the crystallinity of phase-change material as well as melting/crystallization temperature. The novelty of the paper includes 1) protection of the nanostructured energy-enriched materials against environment during storage and controlled release of the encapsulated energy on demand and 2) study of the structure and surface-to-volume properties of the energy-enriched materials dispersed in capsules of different sizes. The stability of energy nanomaterials, influence of capsule diameter on their energy capacity, homogeneity and operation lifetime are investigated. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

THE FINAL DEMISE OF EAST TENNESSEE TECHNOLOGY PARK BUILDING K-33 Health Physics Society Annual Meeting West Palm Beach, Florida June 27, 2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

David A. King

2011-06-27

Building K-33 was constructed in 1954 as the final section of the five-stage uranium enrichment cascade at the Oak Ridge Gaseous Diffusion Plant (ORGDP). The two original building (K-25 and K-27) were used to produce weapons grade highly enriched uranium (HEU). Building K-29, K-31, and K-33 were added to produce low enriched uranium (LEU) for nuclear power plant fuel. During ORGDP operations K-33 produced a peak enrichment of 2.5%. Thousands of tons of reactor tails fed into gaseous diffusion plants in the 1950s and early 1960s introducing some fission products and transuranics. Building K-33 was a two-story, 25-meters (82-feet) tallmore » structure with approximately 30 hectare (64 acres) of floor space. The Operations (first) Floor contained offices, change houses, feed vaporization rooms, and auxiliary equipment to support enrichment operations. The Cell (second) Floor contained the enrichment process equipment and was divided into eight process units (designated K-902-1 through K-902-8). Each unit contained ten cells, and each cell contained eight process stages (diffusers) for a total of 640 enrichment stages. 1985: LEU buildings were taken off-line after the anticipated demand for uranium enrichment failed to materialize. 1987: LEU buildings were placed in permanent shutdown. Process equipment were maintained in a shutdown state. 1997: DOE signed an Action Memorandum for equipment removal and decontamination of Buildings K-29, K-31, K-33; BNFL awarded contract to reindustrialize the buildings under the Three Buildings D&D and Recycle Project. 2002: Equipment removal complete and effort shifts to vacuuming, chemical cleaning, scabbling, etc. 2005: Decontamination efforts in K-33 cease. Building left with significant {sup 99}Tc contamination on metal structures and PCB contamination in concrete. Uranium, transuranics, and fission products also present on building shell. 2009: DOE targets Building K-33 for demolition. 2010: ORAU contracted to characterize Building K-33 for final disposition at the Environmental Management Waste Management Facility (EMWMF) in Oak Ridge. ORAU collected 439 samples from May and June. LATA Sharp started removing transite panels in September. 2011: LATA Sharp began demolition in January and expects the last waste shipment to EMWMF in September. Approximately 237,000 m{sup 3} (310,000 yd{sup 3}, bulked) of waste taken to EMWMF in 23,000 truckloads expected by project completion.« less

Development of an enrichment method for endogenous phosphopeptide characterization in human serum.

PubMed

La Barbera, Giorgia; Capriotti, Anna Laura; Cavaliere, Chiara; Ferraris, Francesca; Laus, Michele; Piovesana, Susy; Sparnacci, Katia; Laganà, Aldo

2018-01-01

The work describes the development of an enrichment method for the analysis of endogenous phosphopeptides in serum. Endogenous peptides can play significant biological roles, and some of them could be exploited as future biomarkers. In this context, blood is one of the most useful biofluids for screening, but a systematic investigation of the endogenous peptides, especially phosphorylated ones, is still lacking, mainly due to the lack of suitable analytical methods. Thus, in this paper, different phosphopeptide enrichment strategies were pursued, based either on metal oxide affinity chromatography (MOAC, in the form of commercial TiO 2 spin columns or magnetic graphitized carbon black-TiO 2 composite), or on immobilized metal ion affinity chromatography (IMAC, in the form of Ti 4+ -IMAC magnetic material or commercial Fe 3+ -IMAC spin columns). While MOAC strategies proved completely unsuccessful, probably due to interfering phospholipids displacing phosphopeptides, the IMAC materials performed very well. Different sample preparation strategies were tested, comprising direct dilution with the loading buffer, organic solvent precipitation, and lipid removal from the matrix, as well as the addition of phosphatase inhibitors during sample handling for maximized endogenous phosphopeptide enrichment. All data were acquired by a shotgun peptidomics approach, in which peptide samples were separated by reversed-phase nanoHPLC hyphenated with high-resolution tandem mass spectrometry. The devised method allowed the identification of 176 endogenous phosphopeptides in fresh serum added with inhibitors by the direct dilution protocol and the Ti 4+ -IMAC magnetic material enrichment, but good results could also be obtained from the commercial Fe 3+ -IMAC spin column adapted to the batch enrichment protocol.

Atrazine and its metabolites degradation in mineral salts medium and soil using an enrichment culture.

PubMed

Kumar, Anup; Singh, Neera

2016-03-01

An atrazine-degrading enrichment culture was used to study degradation of atrazine metabolites viz. hydroxyatrazine, deethylatrazine, and deisopropylatrazine in mineral salts medium. Results suggested that the enrichment culture was able to degrade only hydroxyatrazine, and it was used as the sole source of carbon and nitrogen. Hydroxyatrazine degradation slowed down when sucrose and/or ammonium hydrogen phosphate were supplemented as the additional sources of carbon and nitrogen, respectively. The enrichment culture could degrade high concentrations of atrazine (up to 110 μg/mL) in mineral salts medium, and neutral pH was optimum for atrazine degradation. Further, except in an acidic soil, enrichment culture was able to degrade atrazine in three soil types having different physico-chemical properties. Raising the pH of acidic soil to neutral or alkaline enabled the enrichment culture to degrade atrazine suggesting that acidic pH inhibited atrazine-degrading ability. The study suggested that the enrichment culture can be successfully utilized to achieve complete degradation of atrazine and its persistent metabolite hydroxyatrazine in the contaminated soil and water.

Chemical form of selenium affects its uptake, transport, and glutathione peroxidase activity in the human intestinal Caco-2 cell model.

PubMed

Zeng, Huawei; Jackson, Matthew I; Cheng, Wen-Hsing; Combs, Gerald F

2011-11-01

Determining the effect of selenium (Se) chemical form on uptake, transport, and glutathione peroxidase activity in human intestinal cells is critical to assess Se bioavailability at nutritional doses. In this study, we found that two sources of L-selenomethionine (SeMet) and Se-enriched yeast each increased intracellular Se content more effectively than selenite or methylselenocysteine (SeMSC) in the human intestinal Caco-2 cell model. Interestingly, SeMSC, SeMet, and digested Se-enriched yeast were transported at comparable efficacy from the apical to basolateral sides, each being about 3-fold that of selenite. In addition, these forms of Se, whether before or after traversing from apical side to basolateral side, did not change the potential to support glutathione peroxidase (GPx) activity. Although selenoprotein P has been postulated to be a key Se transport protein, its intracellular expression did not differ when selenite, SeMSC, SeMet, or digested Se-enriched yeast was added to serum-contained media. Taken together, our data show, for the first time, that the chemical form of Se at nutritional doses can affect the absorptive (apical to basolateral side) efficacy and retention of Se by intestinal cells; but that, these effects are not directly correlated to the potential to support GPx activity.

The effects of neem oil (Azadirachta indica A. JUSS) enriched with different concentrations of azadirachtin on the integument of semi-engorged Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) females.

PubMed

Lima de Souza, José Ribamar; Remedio, Rafael Neodini; Arnosti, André; de Abreu, Rusleyd Maria Magalhães; Camargo-Mathias, Maria Izabel

2017-08-01

Several studies searching for methods to control Rhipicephalus sanguineus s.l., (dog tick) infestations have been developed aiming to minimize the damages caused by these ectoparasites to the hosts and the environment, which is harmed by the indiscriminate use of toxic acaricide products. In this scenario, neem oil has been used as a natural alternative against ticks, once this chemical has repellent properties and interferes in the growth regulation of these ectoparasites, inhibiting ecdysis. The present study evaluated the effects of azadirachtin-enriched neem oil on the integument of semi-engorged R.sanguineus s.l., females through morphohistological techniques. The results showed the occurrence of significant morphological and histochemical alterations, mainly in the females exposed to higher concentrations, which demonstrates the dose-dependent action of the chemical. A decrease in the cuticle thickness was observed, as well as a modification in the distribution of the epithelial cells, which displayed pyknotic and fragmented nuclei, and intensely vacuolated cytoplasm, indicating that these cells would be undergoing death processes. These morphological alterations observed in the integument of the females exposed to the azadirachtin-enriched neem oil encourage the use of this chemical as a strategy to control these ectoparasites. © 2017 Wiley Periodicals, Inc.

Ionic liquid biodegradability depends on specific wastewater microbial consortia.

PubMed

Docherty, Kathryn M; Aiello, Steven W; Buehler, Barbara K; Jones, Stuart E; Szymczyna, Blair R; Walker, Katherine A

2015-10-01

Complete biodegradation of a newly-synthesized chemical in a wastewater treatment plant (WWTP) eliminates the potential for novel environmental pollutants. However, differences within- and between-WWTP microbial communities may alter expectations for biodegradation. WWTP communities can also serve as a source of unique consortia that, when enriched, can metabolize chemicals that tend to resist degradation, but are otherwise promising green alternatives. We tested the biodegradability of three ionic liquids (ILs): 1-octyl-3-methylpyridinium bromide (OMP), 1-butyl-3-methylpyridinium bromide (BMP) and 1-butyl-3-methylimidazolium chloride (BMIM). We performed tests using communities from two WWTPs at three time points. Site-specific and temporal variation both influenced community composition, which impacted the success of OMP biodegradability. Neither BMP nor BMIM degraded in any test, suggesting that these ILs are unlikely to be removed by traditional treatment. Following standard biodegradation assays, we enriched for three consortia that were capable of quickly degrading OMP, BMP and BMIM. Our results indicate WWTPs are not functionally redundant with regard to biodegradation of specific ionic liquids. However, consortia can be enriched to degrade chemicals that fail biodegradability assays. This information can be used to prepare pre-treatment procedures and prevent environmental release of novel pollutants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effective Enrichment and Detection of Trace Polycyclic Aromatic Hydrocarbons in Food Samples based on Magnetic Covalent Organic Framework Hybrid Microspheres.

PubMed

Li, Ning; Wu, Di; Hu, Na; Fan, Guangsen; Li, Xiuting; Sun, Jing; Chen, Xuefeng; Suo, Yourui; Li, Guoliang; Wu, Yongning

2018-04-04

The present study reported a facile, sensitive, and efficient method for enrichment and determination of trace polycyclic aromatic hydrocarbons (PAHs) in food samples by employing new core-shell nanostructure magnetic covalent organic framework hybrid microspheres (Fe 3 O 4 @COF-(TpBD)) as the sorbent followed by HPLC-DAD. Under mild synthetic conditions, the Fe 3 O 4 @COF-(TpBD) were prepared with the retention of colloidal nanosize, larger specific surface area, higher porosity, uniform morphology, and supermagnetism. The as-prepared materials showed an excellent adsorption ability for PAHs, and the enrichment efficiency of the Fe 3 O 4 @COF-(TpBD) could reach 99.95%. The obtained materials also had fast adsorption kinetics and realized adsorption equilibrium within 12 min. The eluent was further analyzed by HPLC-DAD, and good linearity was observed in the range of 1-100 ng/mL with the linear correlation being above 0.9990. The limits of detection (S/N = 3) and limits of quantitation (S/N = 10) for 15 PAHs were in the range of 0.83-11.7 ng/L and 2.76-39.0 ng/L, respectively. For the application, the obtained materials were employed for the enrichment of trace PAHs in food samples and exhibited superior enrichment capacity and excellent applicability.

Radiological analysis of plutonium glass batches with natural/enriched boron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rainisch, R.

2000-06-22

The disposition of surplus plutonium inventories by the US Department of Energy (DOE) includes the immobilization of certain plutonium materials in a borosilicate glass matrix, also referred to as vitrification. This paper addresses source terms of plutonium masses immobilized in a borosilicate glass matrix where the glass components include both natural boron and enriched boron. The calculated source terms pertain to neutron and gamma source strength (particles per second), and source spectrum changes. The calculated source terms corresponding to natural boron and enriched boron are compared to determine the benefits (decrease in radiation source terms) for to the use ofmore » enriched boron. The analysis of plutonium glass source terms shows that a large component of the neutron source terms is due to (a, n) reactions. The Americium-241 and plutonium present in the glass emit alpha particles (a). These alpha particles interact with low-Z nuclides like B-11, B-10, and O-17 in the glass to produce neutrons. The low-Z nuclides are referred to as target particles. The reference glass contains 9.4 wt percent B{sub 2}O{sub 3}. Boron-11 was found to strongly support the (a, n) reactions in the glass matrix. B-11 has a natural abundance of over 80 percent. The (a, n) reaction rates for B-10 are lower than for B-11 and the analysis shows that the plutonium glass neutron source terms can be reduced by artificially enriching natural boron with B-10. The natural abundance of B-10 is 19.9 percent. Boron enriched to 96-wt percent B-10 or above can be obtained commercially. Since lower source terms imply lower dose rates to radiation workers handling the plutonium glass materials, it is important to know the achievable decrease in source terms as a result of boron enrichment. Plutonium materials are normally handled in glove boxes with shielded glass windows and the work entails both extremity and whole-body exposures. Lowering the source terms of the plutonium batches will make the handling of these materials less difficult and will reduce radiation exposure to operating workers.« less

An enrichment method based on synergistic and reversible covalent interactions for large-scale analysis of glycoproteins.

PubMed

Xiao, Haopeng; Chen, Weixuan; Smeekens, Johanna M; Wu, Ronghu

2018-04-27

Protein glycosylation is ubiquitous in biological systems and essential for cell survival. However, the heterogeneity of glycans and the low abundance of many glycoproteins complicate their global analysis. Chemical methods based on reversible covalent interactions between boronic acid and glycans have great potential to enrich glycopeptides, but the binding affinity is typically not strong enough to capture low-abundance species. Here, we develop a strategy using dendrimer-conjugated benzoboroxole to enhance the glycopeptide enrichment. We test the performance of several boronic acid derivatives, showing that benzoboroxole markedly increases glycopeptide coverage from human cell lysates. The enrichment is further improved by conjugating benzoboroxole to a dendrimer, which enables synergistic benzoboroxole-glycan interactions. This robust and simple method is highly effective for sensitive glycoproteomics analysis, especially capturing low-abundance glycopeptides. Importantly, the enriched glycopeptides remain intact, making the current method compatible with mass-spectrometry-based approaches to identify glycosylation sites and glycan structures.

Changes in the chemical characteristics of water-extracted organic matter from vermicomposting of sewage sludge and cow dung.

PubMed

Xing, Meiyan; Li, Xiaowei; Yang, Jian; Huang, Zhidong; Lu, Yongsen

2012-02-29

The chemical changes of water-extractable organic matter (WEOM) from five different substrates of sewage sludge enriched with different proportions of cow dung after vermicomposting with Eisenia fetida were investigated using various analytical approaches. Results showed that dissolved organic carbon, chemical oxygen demand, and C/N ratio of the substrates decreased significantly after vermicomposting process. The aromaticity of WEOM from the substrates enhanced considerably, and the amount of volatile fatty acids declined markedly, especially for the cow dung substrate. Gel filtration chromatography analysis showed that the molecular weight fraction between 10(3) and 10(6) Da became the main part of WEOM in the final product. 1H nuclear magnetic resonance spectra revealed that the proportion of H moieties in the area of 0.00-3.00 ppm decreased, while increasing at 3.00-4.25 ppm after vermicomposting. Fluorescence spectra indicated that vermicomposting caused the degradation of protein-like groups, and the formation of fulvic and humic acid-like compounds in the WEOM of the substrates. Overall results indicate clearly that vermicomposting promoted the degradation and transformation of liable WEOM into biological stable substances in sewage sludge and cow dung alone, as well as in mixtures of both materials, and testing the WEOM might be an effective way to evaluate the biological maturity and chemical stability of vermicompost. Copyright © 2011 Elsevier B.V. All rights reserved.

Isotopic Anomalies in Primitive Solar System Matter: Spin-State Dependent Fractionation of Nitrogen and Deuterium in Interstellar Clouds

NASA Technical Reports Server (NTRS)

Wirstrom, Eva S.; Charnley, Steven B.; Cordiner, Martin A.; Milan, Stefanie N.

2012-01-01

Organic material found in meteorites and interplanetary dust particles is enriched in D and N-15, This is consistent with the idea that the functional groups carrying these isotopic anomalies, nitriles and amines, were formed by ion-molecule chemistry in the protosolar core. Theoretical models of interstellar fractionation at low temperatures predict large enrichments in both D and N-15 and can account for the largest isotop c enrichments measured in carbonaceous meteorites, However, more recent measurements have shown that, in some primitive samples, a large N-15 enrichment does not correlate with one in D, and that some D-enriched primitive material displays little, if any, N-15 enrichment. By considering the spin-state dependence in ion-molecule reactions involving the ortho and para forms of H2, we show that ammonia and related molecules can exhibit such a wide range of fractionation for both N-15 and D in dense cloud cores, We also show that while the nitriles, HCN and HNC, contain the greatest N-15 enrichment, this is not expected to correlate with extreme D emichment. These calculations therefore support the view that Solar System N-15 and D isotopic anomalies have an interstellar heritage, We also compare our results to existing astronomical observations and briefly discuss future tests of this model.

Laboratory mouse housing conditions can be improved using common environmental enrichment without compromising data

PubMed Central

Gau, Christine; Scheideler, Angelika; Aguilar-Pimentel, Juan A.; Amarie, Oana V.; Becker, Lore; Garrett, Lillian; Hans, Wolfgang; Hölter, Sabine M.; Janik, Dirk; Moreth, Kristin; Neff, Frauke; Östereicher, Manuela; Racz, Ildiko; Rathkolb, Birgit; Rozman, Jan; Bekeredjian, Raffi; Graw, Jochen; Klingenspor, Martin; Klopstock, Thomas; Ollert, Markus; Schmidt-Weber, Carsten; Wolf, Eckhard; Wurst, Wolfgang; Gailus-Durner, Valérie; Brielmeier, Markus; Fuchs, Helmut; Hrabé de Angelis, Martin

2018-01-01

Animal welfare requires the adequate housing of animals to ensure health and well-being. The application of environmental enrichment is a way to improve the well-being of laboratory animals. However, it is important to know whether these enrichment items can be incorporated in experimental mouse husbandry without creating a divide between past and future experimental results. Previous small-scale studies have been inconsistent throughout the literature, and it is not yet completely understood whether and how enrichment might endanger comparability of results of scientific experiments. Here, we measured the effect on means and variability of 164 physiological parameters in 3 conditions: with nesting material with or without a shelter, comparing these 2 conditions to a “barren” regime without any enrichments. We studied a total of 360 mice from each of 2 mouse strains (C57BL/6NTac and DBA/2NCrl) and both sexes for each of the 3 conditions. Our study indicates that enrichment affects the mean values of some of the 164 parameters with no consistent effects on variability. However, the influence of enrichment appears negligible compared to the effects of other influencing factors. Therefore, nesting material and shelters may be used to improve animal welfare without impairment of experimental outcome or loss of comparability to previous data collected under barren housing conditions. PMID:29659570

Supplements to Textbook Materials.

ERIC Educational Resources Information Center

Holmes, Ken

1994-01-01

Describes the many kinds of materials that English teachers can draw upon to enrich and expand students' experiences with literature. Outlines ancillary materials used to supplement the study of William Shakespeare's "Julius Caesar." (HB)

Chemical stratification of cratonic lithosphere: constraints from the Northern Slave craton, Canada

NASA Astrophysics Data System (ADS)

Kopylova, Maya G.; Russell, James K.

2000-08-01

We describe the mineralogical and chemical composition of the Northern Slave mantle as deduced from xenoliths of peridotite within the Jericho kimberlite, Northwest Territories. Our data set includes modal, major, trace and rare earth element compositions of bulk samples of spinel peridotite, low-T and high-T garnet peridotite and minor pyroxenite. Compared to primitive upper mantle, Jericho peridotite shows depletion in the major elements and enrichment in incompatible elements (except for HREE). The Slave mantle is also uniquely stratified. Older, depleted spinel peridotite extends to a depth of 80-100 km and is underlain by garnet peridotite which shows a gradual decrease in Mg# with depth to 200 km. The youngest layer of fertile garnet peridotite, enriched in clinopyroxene and garnet, is underlain by a pyroxenite-rich horizon at the base of the petrological lithosphere. The Northern Slave is further distinguished from the Kaapvaal and Siberian upper mantle by a marked vertical stratification in Mg#, lower abundances of orthopyroxene and higher abundances of clinopyroxene. In addition, a deeper layer of garnet peridotite below Jericho shows less depletion than low-T peridotite from other cratons. The Northern Slave peridotite results from a series of chemical events that include: (i) high-degree melting of pyrolite at P>3 Gpa for low-T peridotite and lower pressure melting for high-T peridotite, (ii) enrichment of low-T spinel peridotite in orthopyroxene, and (iii) pervasive metasomatic enrichment in alkali and LREE's by kimberlite-related fluids. The chemical stratification described for two of the three lithospheric domains of the Slave craton makes this craton an exception among cratons with commonly unstratified lithospheres. The gradual increase in fertility with depth below the Slave craton is related to age stratification and may have formed by incremental downward growth of mantle lithosphere with time, and/or later re-fertilization of deeper mantle horizons.

Direct sampling of sub-µm atmospheric particulate organic matter in sub-ng m-3 mass concentrations by proton-transfer-reaction mass spectrometry

NASA Astrophysics Data System (ADS)

Armin, W.; Mueller, M.; Klinger, A.; Striednig, M.

2017-12-01

A quantitative characterization of the organic fraction of atmospheric particulate matter is still challenging. Herein we present the novel modular "Chemical Analysis of Aerosol Online" (CHARON) particle inlet system coupled to a new-generation proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF 6000 X2, Ionicon Analytik, Austria) that quantitatively detects organic analytes in real-time and sub-pptV levels by chemical ionization with hydronium reagent ions. CHARON consists of a gas-phase denuder for stripping off gas-phase analytes (efficiency > 99.999%), an aerodynamic lens for particle collimation combined with an inertial sampler for the particle-enriched flow and a thermodesorption unit for particle volatilization prior to chemical analysis. With typical particle enrichment factors of around 30 for particle diameters (DP) between 120 nm and 1000 nm (somewhat reduced enrichment for 60 nm < DP < 120 nm) we boost the already excellent limits of detection of the PTR-TOF 6000 X2 system to unprecedented levels. We demonstrate that particulate organic analytes of mass concentrations down to 100 pg m-3 can be detected on-line and in single-minute time-resolutions. In addition, PTR-MS allows for a quantitative detection of almost the full range of particulate organics of intermediate to low volatility. With the high mass resolution (R > 6000) and excellent mass accuracies (< 10 ppm) chemical compositions can be assigned and included in further analyses. In addition to a detailed characterization of the CHARON PTR-TOF 6000 X2 we will present first results on the chemical composition of sub-µm particulate organic matter in the urban atmosphere in Innsbruck (Austria).

Preparation and properties of ZnS superhydrophobic surface with hierarchical structure

NASA Astrophysics Data System (ADS)

Yao, Lujun; Zheng, Maojun; He, Shuanghu; Ma, Li; Li, Mei; Shen, Wenzhong

2011-01-01

A novel ZnS hierarchical structure composed of nanorod arrays with branched nanosheets and nanowires grown on their upside walls, was synthesized over Au-coated silicon substrate via chemical vapor deposition technique. Contact angle and sliding angle of this hierarchical film with no surface modification were measured to be about 153.8° and 9.1° for 5 μl water droplets. Self-cleaning behavior and dynamic water-repelling performance were clearly demonstrated. In addition, electrowetting transition phenomenon from superhydrophobic to hydrophilic state happened when a critical bias ∼7.0 V was applied. Below this threshold voltage, the contact angle change is little. This work for the first time reports the creation of ZnS superhydrophobic surface and could enrich its research field as surface functional materials.

Organic molecules as tools to control the growth, surface structure, and redox activity of colloidal quantum dots.

PubMed

Weiss, Emily A

2013-11-19

In order to achieve efficient and reliable technology that can harness solar energy, the behavior of electrons and energy at interfaces between different types or phases of materials must be understood. Conversion of light to chemical or electrical potential in condensed phase systems requires gradients in free energy that allow the movement of energy or charge carriers and facilitate redox reactions and dissociation of photoexcited states (excitons) into free charge carriers. Such free energy gradients are present at interfaces between solid and liquid phases or between inorganic and organic materials. Nanostructured materials have a higher density of these interfaces than bulk materials. Nanostructured materials, however, have a structural and chemical complexity that does not exist in bulk materials, which presents a difficult challenge: to lower or eliminate energy barriers to electron and energy flux that inevitably result from forcing different materials to meet in a spatial region of atomic dimensions. Chemical functionalization of nanostructured materials is perhaps the most versatile and powerful strategy for controlling the potential energy landscape of their interfaces and for minimizing losses in energy conversion efficiency due to interfacial structural and electronic defects. Colloidal quantum dots are semiconductor nanocrystals synthesized with wet-chemical methods and coated in organic molecules. Chemists can use these model systems to study the effects of chemical functionalization of nanoscale organic/inorganic interfaces on the optical and electronic properties of a nanostructured material, and the behavior of electrons and energy at interfaces. The optical and electronic properties of colloidal quantum dots have an intense sensitivity to their surface chemistry, and their organic adlayers make them dispersible in solvent. This allows researchers to use high signal-to-noise solution-phase spectroscopy to study processes at interfaces. In this Account, I describe the varied roles of organic molecules in controlling the structure and properties of colloidal quantum dots. Molecules serve as surfactant that determines the mechanism and rate of nucleation and growth and the final size and surface structure of a quantum dot. Anionic surfactant in the reaction mixture allows precise control over the size of the quantum dot core but also drives cation enrichment and structural disordering of the quantum dot surface. Molecules serve as chemisorbed ligands that dictate the energetic distribution of surface states. These states can then serve as thermodynamic traps for excitonic charge carriers or couple to delocalized states of the quantum dot core to change the confinement energy of excitonic carriers. Ligands, therefore, in some cases, dramatically shift the ground state absorption and photoluminescence spectra of quantum dots. Molecules also act as protective layers that determine the probability of redox processes between quantum dots and other molecules. How much the ligand shell insulates the quantum dot from electron exchange with a molecular redox partner depends less on the length or degree of conjugation of the native ligand and more on the density and packing structure of the adlayer and the size and adsorption mode of the molecular redox partner. Control of quantum dot properties in these examples demonstrates that nanoscale interfaces, while complex, can be rationally designed to enhance or specify the functionality of a nanostructured system.

Review of remediation practices regarding cadmium-enriched farmland soil with particular reference to China.

PubMed

Tang, X; Li, Q; Wu, M; Lin, L; Scholz, M

2016-10-01

Cadmium-enrichment of farmland soil greatly threatens the sustainable use of soil resources and the safe cultivation of grain. This review paper briefly introduces the status of farmland soil as well as grain, which are both often polluted by cadmium (Cd) in China, and illustrates the major sources of Cd contaminants in farmland soil. In order to meet soil environmental quality standards and farmland environmental quality evaluation standards for edible agricultural products, Cd-enriched farmland soil is frequently remediated with the following prevailing techniques: dig and fill, electro-kinetic remediation, chemical elution, stabilisation and solidification, phytoremediation, field management and combined remediation. Most remediation techniques are still at the stage of small-scale trial experiments in China and few techniques are assessed in field trials. After comparing the technical and economical applicability among different Cd-enriched farmland soil remediation techniques, a novel ecological and hydraulic remediation technique has been proposed, which integrated the advantages of chemical elution, solidification and stabilisation, phytoremediation and field management. The ecological and hydraulic remediation concept is based on existing irrigation and drainage facilities, ecological ditches (ponds) and agronomic measures, which mainly detoxify the Cd-enriched soil during the interim period of crop cultivation, and guarantee the grain safety during its growth period. This technique may shift the challenge from soil to water treatment, and thus greatly enhances the remediation efficiency and shortens the remediation duration. Moreover, the proposed ecological and hydraulic remediation method matches well with the practical choice of cultivation while remediation for Cd-enriched soil in China, which has negligible impacts on the normal crop cultivation process, and thus shows great potential for large area applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Energetic particle observations of the solar-gamma ray/neutron flare events of 3 Jun 1982 and 21 June 1980 isotopic and chemical composition

NASA Technical Reports Server (NTRS)

Vanhollebeke, M. A. I.; Mcdonald, F. B.; Trainor, J. H.

1985-01-01

Studies of the charge composition of two solar gamma ray/neutron-flare events reveal a striking enrichment of iron relative to oxygen with a smaller enrichment of intermediate nuclei. He/O is also enhanced and moderate amounts of He-3 are detected but there is no evidence for H-2 or H-3.

Performance evaluation of PRIDE UNDA system with pyroprocessing feed material.

PubMed

An, Su Jung; Seo, Hee; Lee, Chaehun; Ahn, Seong-Kyu; Park, Se-Hwan; Ku, Jeong-Hoe

2017-04-01

The PRIDE (PyRoprocessing Integrated inactive DEmonstration) is an engineering-scale pyroprocessing test-bed facility that utilizes depleted uranium (DU) instead of spent fuel as a process material. As part of the ongoing effort to enhance pyroprocessing safeguardability, UNDA (Unified Non-Destructive Assay), a system integrating three different non-destructive assay techniques, namely, neutron, gamma-ray, and mass measurement, for nuclear material accountancy (NMA) was developed. In the present study, UNDA's NMA capability was evaluated by measurement of the weight, 238 U mass, and U enrichment of oxide-reduction-process feed material (i.e., porous pellets). In the 238 U mass determination, the total neutron counts for porous pellets of six different weights were measured. The U enrichment of the porous pellets, meanwhile, was determined according to the gamma spectrums acquired using UNDA's NaI-based enrichment measurement system. The results demonstrated that the UNDA system, after appropriate corrections, could be used in PRIDE NMA applications with reasonable uncertainty. It is expected that in the near future, the UNDA system will be tested with next-step materials such as the products of the oxide-reduction and electro-refining processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Static sublimation purification process and characterization of LiZnAs semiconductor material

NASA Astrophysics Data System (ADS)

Montag, Benjamin W.; Reichenberger, Michael A.; Edwards, Nathaniel S.; Ugorowski, Philip B.; Sunder, Madhana; Weeks, Joseph; McGregor, Douglas S.

2016-03-01

Refinement of the class AIBIICV materials continue as a candidate for solid-state neutron detectors. Such a device would have greater efficiency, in a compact form, than present day gas-filled 3He and 10BF3 detectors. The 6Li(n,t)4He reaction yields a total Q value of 4.78 MeV, larger than 10B, and easily identified above background radiations. Hence, devices composed of either natural Li (nominally 7.5% 6Li) or enriched 6Li (usually 95% 6Li) may provide a semiconductor material for compact high efficiency neutron detectors. A sub-branch of the III-V semiconductors, the filled tetrahedral compounds, AIBIICV, known as Nowotny-Juza compounds, are known for their desirable cubic crystal structure. Starting material was synthesized by equimolar portions of Li, Zn, and As sealed under vacuum (10-6 Torr) in quartz ampoules with a boron nitride lining, and reacted in a compounding furnace [1]. The synthesized material showed signs of high impurity levels from material and electrical property characterization. In the present work, a static vacuum sublimation of synthesized LiZnAs loaded in a quartz vessel was performed to help purify the synthesized material. The chemical composition of the sublimed material and remains material was confirmed by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Lithium was not detected in the sublimed material, however, near stoichiometric amounts of each constituent element were found in the remains material for LiZnAs. X-ray diffraction phase identification scans of the remains material and sublimed material were compared, and further indicated the impurity materials were removed from the synthesized materials. The remaining powder post the sublimation process showed characteristics of a higher purity ternary compound.

Isolation and characterization of cellulose nanofibers from bamboo using microwave liquefaction combined with chemical treatment and ultrasonication

Treesearch

Jiulong Xie; Chung Hse; Cornelis F. De Hoop; Tingxing Hu; Jinqiu Qi; Todd F. Shupe

2016-01-01

Cellulose nanofibers were successfully isolated from bamboo using microwave liquefaction combinedwith chemical treatment and ultrasonic nanofibrillation processes. The microwave liquefaction couldeliminate almost all the lignin in bamboo, resulting in high cellulose content residues within 7 min, andthe cellulose enriched residues could be readily purified by...

[Characteristics of Chemical Components in PM₂.₅ from the Coal Dust of Power Plants].

PubMed

Wang, Yu-xiu; Peng, Lin; Wang, Yan; Zhang, Teng; Liu, Hai-li; Mu, Ling

2016-01-15

The ashes under dust catcher of typical power plants in Yangquan was collected and the contents of elements, irons, EC (elemental carbon) and OC (organic carbon) were measured in PM₂. The characteristics of its chemical composition was studied and the degree of similarity of coal dust's source profiles of PM₂.₅ between Yangquan and other cities were compared using the coefficient of divergence method. The result indicated that the main chemical components of PM₂.₅ from the coal dust were SO₄²⁻,Ca, NO₃⁻, OC, EC, Al, Si, Na, Fe, Mg and Cl⁻, accounting for 57.22% of the total mass. The enrichment factor of Pb in PM₂.₅ of coal dust was the largest with a significant enrichment condition, reaching 10.66-15.91. The coefficient of divergence of source profiles of PM₂.₅ between blind coal and fault coal was 0.072, so it was believed that they must be similar. Compared with other cities, the chemical composition of coal dust in Yangquan had specificity, in particular, the content of Ca was obviously higher than those in other domestic cities.

Magnesium-Assisted Continuous Growth of Strongly Iron-Enriched Incisors.

PubMed

Srot, Vesna; Bussmann, Birgit; Salzberger, Ute; Deuschle, Julia; Watanabe, Masashi; Pokorny, Boštjan; Jelenko Turinek, Ida; Mark, Alison F; van Aken, Peter A

2017-01-24

Teeth are an excellent example where optimally designed nanoarchitectures with precisely constructed components consist of simple compounds. Typically, these simple constituent phases with insignificant properties show mechanical property amplifications when formed into composite architectures. Material properties of functional composites are generally regulated on the nanoscale, which makes their characterization particularly demanding. Using advanced analytical and imaging transmission electron microscopy techniques, we identified innovative microstructural adjustments combined with astonishing compositional adaptations in incisors of coypu. Unique constituents, recognized as an additional amorphous Fe-rich surface layer followed by a transition zone covering pigmented enamel, provide the required structural stability to withstand repeated mechanical load. The chemically diverse Fe-rich surface layer, including ferrihydrite and iron-calcium phosphates, gives the typical orange-brown coloration to the incisors. Within the spaces between elongated hydroxyapatite crystals in the pigmented enamel, only ferrihydrite was found, implying that enamel pigmentation is a very strictly controlled process. Most significantly, an unprecedentedly high amount of Mg was measured in the amorphous flake-like material within the dentinal tubules of the incisors, suggesting the presence of a (Mg,Ca) phosphate phase. This unusually high influx of Mg into the dentin of incisors, but not molars, suggests a substantial functionality of Mg in the initial formation stages and constant growth of incisors. The present results emphasize the strong mutual correlation among the microstructure, chemical composition, and mechanical properties of mineralized dental tissues.

Chemical characterization of fractions of dissolved humic substances from a marginal sea—a case from the Southern Yellow Sea

NASA Astrophysics Data System (ADS)

Zhang, Yaoling; Yang, Keli; Du, Jinzhou; Zhang, Fenfen; Dong, Yaping; Li, Wu

2018-03-01

Marine dissolved organic matter (DOM) is one of the largest dynamic pools of organic carbon in the global carbon cycle, yet DOM is still chemically poorly characterized. To better understand the origin, composition, and cycling of DOM in the China marginal sea, dissolved humic substances (DHS) were isolated from seawaters in two locations in the Southern Yellow Sea. The DHS were subdivided into fulvic acids (FAs), humic acids (HAs) and the XAD-4 fractions. Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition, Fourier transform infrared spectroscopy (FTIR), 13C cross polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The results demonstrated that both DHS samples encountered the influences from marine source, indicating that algal and microbial-derived materials are the predominant precursors for the studied samples. The three fractions of DHS showed different properties. FAs presented more aromatic features, whereas HAs contained more aliphatic lipids and proteinaceous materials. The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds. The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species, bioavailability of pollutants, mineral weathering and water acidification in marine environments.

Chemical and Physical Properties, Safety and Application of Partially Hydrolized Guar Gum as Dietary Fiber

PubMed Central

Yoon, Seon-Joo; Chu, Djong-Chi; Raj Juneja, Lekh

2008-01-01

The ideal water-soluble dietary fiber for the fiber-enrichment of foods must be very low in viscosity, tasteless, odorless, and should produce clear solutions in beverages. Partially hydrolyzed guar gum (PHGG) produced from guar gum by enzymatic process has the same chemical structure with intact guar gum but less than one-tenth the original molecular length of guar gum, which make available to be used as film former, foam stabilizer and swelling agent. The viscosity of PHGG is about 10 mPa·s in 5% aqueous solution, whereas 1% solution of guar gum shows range from 2,000 to 3,000 mPa·s. In addition, PHGG is greatly stable against low pH, heat, acid and digestive enzyme. For these reasons, PHGG seems to be one of the most beneficial dietary fiber materials. It also showed that interesting physiological functions still fully exert the nutritional function of a dietary fiber. PHGG has, therefore, been used primarily for a nutritional purpose and became fully integrated food material without altering the rheology, taste, texture and color of final products. PHGG named as Benefiber® in USA has self-affirmation on GRAS status of standard grade PHGG. PHGG named as Sunfiber® is now being used in various beverages, food products and medicinal foods as a safe, natural and functional dietary fiber in all over the world. PMID:18231623

The Proliferation Security Initiative: A Means to an End for the Operational Commander

DTIC Science & Technology

2009-05-04

The Reduced Enrichment for Research and Test Reactors ( RERTR ) Program develops technology necessary to enable the conversion of civilian...facilities using high enriched uranium (HEU) to low enriched uranium (LEU) fuels and targets. The RERTR Program was initiated by the U.S. Department of...processes have been developed for producing radioisotopes with LEU targets. The RERTR Program is managed by the Office of Nuclear Material Threat

Proposal for Monitoring Within the Centrifuge Cascades of Uranium Enrichment Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farrar, David R.

2017-04-01

Safeguards are technical measures implemented by the International Atomic Energy Agency (IAEA) to independently verify that nuclear material is not diverted from peaceful purposes to weapons (IAEA, 2017a). Safeguards implemented at uranium enrichment facilities (facilities hereafter) include enrichment monitors (IAEA, 2011). Figure 1 shows a diagram of how a facility could be monitored. The use of a system for monitoring within centrifuge cascades is proposed.

High liquid yield process for retorting various organic materials including oil shale

DOEpatents

Coburn, Thomas T.

1990-01-01

This invention is a continuous retorting process for various high molecular weight organic materials, including oil shale, that yields an enhanced output of liquid product. The organic material, mineral matter, and an acidic catalyst, that appreciably adsorbs alkenes on surface sites at prescribed temperatures, are mixed and introduced into a pyrolyzer. A circulating stream of olefin enriched pyrolysis gas is continuously swept through the organic material and catalyst, whereupon, as the result of pyrolysis, the enhanced liquid product output is provided. Mixed spent organic material, mineral matter, and cool catalyst are continuously withdrawn from the pyrolyzer. Combustion of the spent organic material and mineral matter serves to reheat the catalyst. Olefin depleted pyrolysis gas, from the pyrolyzer, is enriched in olefins and recycled into the pyrolyzer. The reheated acidic catalyst is separated from the mineral matter and again mixed with fresh organic material, to maintain the continuously cyclic process.

A high liquid yield process for retorting various organic materials including oil shale

DOEpatents

Coburn, T.T.

1988-07-26

This invention is a continuous retorting process for various high molecular weight organic materials, including oil shale, that yields an enhanced output of liquid product. The organic material, mineral matter, and an acidic catalyst, that appreciably adsorbs alkenes on surface sites at prescribed temperatures, are mixed and introduced into a pyrolyzer. A circulating stream of olefin enriched pyrolysis gas is continuously swept through the organic material and catalyst, whereupon, as the result of pyrolysis, the enhanced liquid product output is provided. Mixed spent organic material, mineral matter, and cool catalyst are continuously withdrawn from the pyrolyzer. Combustion of the spent organic material and mineral matter serves to reheat the catalyst. Olefin depleted pyrolysis gas, from the pyrolyzer, is enriched in olefins and recycled into the pyrolyzer. The reheated acidic catalyst is separated from the mineral matter and again mixed with fresh organic material, to maintain the continuously cyclic process. 2 figs.

Reactor Physics Measurements and Benchmark Specifications for Oak Ridge Highly Enriched Uranium Sphere (ORSphere)

DOE PAGES

Marshall, Margaret A.

2014-11-04

In the early 1970s Dr. John T. Mihalczo (team leader), J.J. Lynn, and J.R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) in an effort to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950s. The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with themore » GODIVA I experiments. Additionally, various material reactivity worths, the surface material worth coefficient, the delayed neutron fraction, the prompt neutron decay constant, relative fission density, and relative neutron importance were all measured. The critical assembly, material reactivity worths, the surface material worth coefficient, and the delayed neutron fraction were all evaluated as benchmark experiment measurements. The reactor physics measurements are the focus of this paper; although for clarity the critical assembly benchmark specifications are briefly discussed.« less

Enriching the Housing Environment for Mice Enhances Their NK Cell Antitumor Immunity via Sympathetic Nerve-Dependent Regulation of NKG2D and CCR5.

PubMed

Song, Yanfang; Gan, Yu; Wang, Qing; Meng, Zihong; Li, Guohua; Shen, Yuling; Wu, Yufeng; Li, Peiying; Yao, Ming; Gu, Jianren; Tu, Hong

2017-04-01

Mice housed in an enriched environment display a tumor-resistant phenotype due to eustress stimulation. However, the mechanisms underlying enriched environment-induced protection against cancers remain largely unexplained. In this study, we observed a significant antitumor effect induced by enriched environment in murine pancreatic cancer and lung cancer models. This effect remained intact in T/B lymphocyte-deficient Rag1 -/- mice, but was nearly eliminated in natural killer (NK) cell-deficient Beige mice or in antibody-mediated NK-cell-depleted mice, suggesting a predominant role of NK cells in enriched environment-induced tumor inhibition. Exposure to enriched environment enhanced NK-cell activity against tumors and promoted tumoral infiltration of NK cells. Enriched environment increased the expression levels of CCR5 and NKG2D (KLRK1) in NK cells; blocking their function effectively blunted the enriched environment-induced enhancement of tumoral infiltration and cytotoxic activity of NK cells. Moreover, blockade of β-adrenergic signaling or chemical sympathectomy abolished the effects of enriched environment on NK cells and attenuated the antitumor effect of enriched environment. Taken together, our results provide new insight into the mechanism by which eustress exerts a beneficial effect against cancer. Cancer Res; 77(7); 1611-22. ©2017 AACR . ©2017 American Association for Cancer Research.

Chemical fractionation in the solar nebula

NASA Technical Reports Server (NTRS)

Grossman, L.

1977-01-01

The sequence of condensation of minerals from a cooling gas of solar composition has been calculated from thermodynamic data over the pressure range 0.001-0.00001 atm, assuming that complete chemical equilibrium is maintained. The results suggest that the Ca-Al-rich inclusions Allende and other carbonaceous chondrites are aggregates of the highest temperature condensates. Complete condensation of these elements is followed, 100 deg later, by the onset of the crystallization of nickel-iron, forsterite and enstatite. Transport of Ca-Al-rich refractory condensates from one part of the nebula to another before the condensation of these lower-temperature phases may have been responsible for the refractory element fractionations between the different classes of chondrites and possibly for the inferred refractory element enrichment of the Moon. The temperature gap between the condensation temperatures of nickel-iron and forsterite increases with increasing total pressure. Because pressure and temperature probably increased with decreasing heliocentric distance in the solar nebula, Mercury may have accreted from a condensate assemblage having a higher metal/silicate ratio than Venus or Earth which may, in turn, have formed from less oxidized material than Mars.

The value of iodide as a parameter in the chemical characterisation of groundwaters

NASA Astrophysics Data System (ADS)

Lloyd, J. W.; Howard, K. W. F.; Pacey, N. R.; Tellam, J. H.

1982-06-01

Brackish and saline groundwaters can severely constrain the use of fresh groundwaters. Their chemical characterisation is important in understanding the hydraulic conditions controlling their presence in an aquifer. Major ions are frequently of limited value but minor ions can be used. Iodide in groundwater is particularly significant in many environments due to the presence of soluble iodine in aquifer matrix materials. Iodide is found in groundwaters in parts of the English Chalk aquifer in concentrations higher than are present in modern seawater. Its presence is considered as a indication of groundwater residence and is of use in the characterisation of fresh as well as saline waters. Under certain circumstances modern seawater intrusion into aquifers along English estuaries produces groundwaters which are easily identified due to iodide enrichment from estuarine muds. In other environments iodide concentrations are of value in distinguishing between groundwaters in limestones and shaly gypsiferous rocks as shown by a study in Qatar, while in an alluvial aquifer study in Peru iodide has been used to identify groundwaters entering the aquifer from adjacent granodiorites.

Dwarfs on a Low-Carbon Diet: Modelling the Chemically Peculiar Secondaries of CVs

NASA Astrophysics Data System (ADS)

Homeier, D.; Harrison, T. E.; Barman, T. S.; Howell, S. B.

2003-12-01

Secondary stars of cataclysmic variables show a variety of abundance anomalies that might be caused by deposition of CNO-processed material. We have calculated PHOENIX stellar atmosphere models for late-type stellar and substellar companions using chemical equilibrium compositions for a range of carbon-depleted and/or oxygen-enriched elemental abundances. We present comparisons of our models with medium-resolution IR spectra of CV secondaries, including the possibly substellar secondary of the EF Eridani system. LTE models of the K-band spectrum are consistent with a Teff in the brown dwarf range and show that the complete lack of CH4 and CO absorption features in this object requires a [C/Fe] ratio more than 2 dex below the solar value. We compare our models to temperature estimates from light curve analyses and present a first irradiated model of the secondary, that takes into account the effect of the impinging flux from the white dwarf primary. This project has been supported by grants from the National Science Foundation and the NASA NStars program.

Evaluation of bacterial diversity recovered from petroleum samples using different physical matrices.

PubMed

Dellagnezze, Bruna Martins; Vasconcellos, Suzan Pantaroto de; Melo, Itamar Soares de; Santos Neto, Eugênio Vaz Dos; Oliveira, Valéria Maia de

2016-01-01

Unraveling the microbial diversity and its complexity in petroleum reservoir environments has been a challenge throughout the years. Despite the techniques developed in order to improve methodologies involving DNA extraction from crude oil, microbial enrichments using different culture conditions can be applied as a way to increase the recovery of DNA from environments with low cellular density for further microbiological analyses. This work aimed at the evaluation of different matrices (arenite, shale and polyurethane foam) as support materials for microbial growth and biofilm formation in enrichments using a biodegraded petroleum sample as inoculum in sulfate reducing condition. Subsequent microbial diversity characterization was carried out using Scanning Electronic Microscopy (SEM), Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rRNA gene libraries in order to compare the microbial biomass yield, DNA recovery efficiency and diversity among the enrichments. The DNA from microbial communities in petroleum enrichments was purified according to a protocol established in this work and used for 16S rRNA amplification with bacterial generic primers. The PCR products were cloned, and positive clones were screened by Amplified Ribosomal DNA Restriction Analysis (ARDRA). Sequencing and phylogenetic analyses revealed that the bacterial community was mostly represented by members of the genera Petrotoga, Bacillus, Pseudomonas, Geobacillus and Rahnella. The use of different support materials in the enrichments yielded an increase in microbial biomass and biofilm formation, indicating that these materials may be employed for efficient biomass recovery from petroleum reservoir samples. Nonetheless, the most diverse microbiota were recovered from the biodegraded petroleum sample using polyurethane foam cubes as support material. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Simulated Screens of DNA Encoded Libraries: The Potential Influence of Chemical Synthesis Fidelity on Interpretation of Structure-Activity Relationships.

PubMed

Satz, Alexander L

2016-07-11

Simulated screening of DNA encoded libraries indicates that the presence of truncated byproducts complicates the relationship between library member enrichment and equilibrium association constant (these truncates result from incomplete chemical reactions during library synthesis). Further, simulations indicate that some patterns observed in reported experimental data may result from the presence of truncated byproducts in the library mixture and not structure-activity relationships. Potential experimental methods of minimizing the presence of truncates are assessed via simulation; the relationship between enrichment and equilibrium association constant for libraries of differing purities is investigated. Data aggregation techniques are demonstrated that allow for more accurate analysis of screening results, in particular when the screened library contains significant quantities of truncates.

Materials and Mechanisms of Photo-Assisted Chemical Reactions under Light and Dark Conditions: Can Day-Night Photocatalysis Be Achieved?

PubMed

Sakar, M; Nguyen, Chinh-Chien; Vu, Manh-Hiep; Do, Trong-On

2018-03-09

The photoassisted catalytic reaction, conventionally known as photocatalysis, is expanding into the field of energy and environmental applications. It is widely known that the discovery of TiO 2 -assisted photochemical reactions has led to several unique applications, such as degradation of pollutants in water and air, hydrogen production through water splitting, fuel conversion, cancer treatment, antibacterial activity, self-cleaning glasses, and concrete. These multifaceted applications of this phenomenon can be enriched and expanded further if this process is equipped with more tools and functions. The term "photoassisted" catalytic reactions clearly emphasizes that photons are required to activate the catalyst; this can be transcended even into the dark if electrons are stored in the material for the later use to continue the catalytic reactions in the absence of light. This can be achieved by equipping the photocatalyst with an electron-storage material to overcome current limitations in photoassisted catalytic reactions. In this context, this article sheds lights on the materials and mechanisms of photocatalytic reactions under light and dark conditions. The manifestation of such systems could be an unparalleled technology in the near future that could influence all spheres of the catalytic sciences. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Large n- and p-type thermoelectric power factors from doped semiconducting single-walled carbon nanotube thin films

DOE PAGES

MacLeod, Bradley A.; Stanton, Noah J.; Gould, Isaac E.; ...

2017-09-08

Lightweight, robust, and flexible single-walled carbon nanotube (SWCNT) materials can be processed inexpensively using solution-based techniques, similar to other organic semiconductors. In contrast to many semiconducting polymers, semiconducting SWCNTs (s-SWCNTs) represent unique one-dimensional organic semiconductors with chemical and physical properties that facilitate equivalent transport of electrons and holes. These factors have driven increasing attention to employing s-SWCNTs for electronic and energy harvesting applications, including thermoelectric (TE) generators. Here we demonstrate a combination of ink chemistry, solid-state polymer removal, and charge-transfer doping strategies that enable unprecedented n-type and p-type TE power factors, in the range of 700 μW m –1 Kmore » –2 at 298 K for the same solution-processed highly enriched thin films containing 100% s-SWCNTs. We also demonstrate that the thermal conductivity appears to decrease with decreasing s-SWCNT diameter, leading to a peak material zT ≈ 0.12 for s-SWCNTs with diameters in the range of 1.0 nm. Here, our results indicate that the TE performance of s-SWCNT-only material systems is approaching that of traditional inorganic semiconductors, paving the way for these materials to be used as the primary components for efficient, all-organic TE generators.« less

Redistribution of elements between wastes and organic-bearing material in the dispersion train of gold-bearing sulfide tailings: Part I. Geochemistry and mineralogy.

PubMed

Saryg-Ool, B Yu; Myagkaya, I N; Kirichenko, I S; Gustaytis, M A; Shuvaeva, O V; Zhmodik, S M; Lazareva, E V

2017-03-01

Migration and redistribution of elements during prolonged interaction of cyanide wastes with the underlying natural organic-bearing material have been studied in two ~40cm deep cores that sample primary ores and their weathering profile (wastes I and II, respectively) in the dispersion train of gold-bearing sulfide tailings in Siberia. Analytical results of SR-XRF, whole-rock XRF, AAS, CHNS, and SEM measurements of core samples show high K, Sr, Ti, and Fe enrichments and correlation of P 2 O 5 and Mn with LOI and C org . Organic material interlayered or mixed with the wastes accumulates Cu, Zn, Se, Cd, Ag, Au, and Hg. The peat that contacts wastes II bears up to 3wt.% Zn, 1000g/t Se, 100g/t Cd, and 8000g/t Hg. New phases of Zn and Hg sulfides and Hg selenides occur as abundant sheaths over bacterial cells suggesting microbial mediation in sorption of elements. Organic-bearing material in the cores contains 10-30g/t Au in 2-5cm thick intervals, both within and outside the intervals rich in sulfides and selenides. Most of gold is invisible but reaches 345g/t and forms 50nm to 1.5μm Au 0 particles in a thin 2-3cm interval of organic remnants mixed with wastes I. Vertical and lateral infiltration of AMD waters in peat and oxidative dissolution of wastes within the dispersion train of the Ursk tailings lead to redistribution of elements and their accumulation by combined physical (material's permeability, direction AMD), chemical (complexing, sorption by organic matter and Fe(III) hydroxides) and biochemical (metabolism of sulfate-reducing bacteria) processes. The accumulated elements form secondary sulfates, and Hg and Zn selenides. The results provide insights into accumulation of elements in the early history of coal and black shale deposits and have implications for remediation of polluted areas and for secondary enrichment technologies. Copyright © 2017 Elsevier B.V. All rights reserved.

On the chemical dynamics of extracellular polysaccharides in the high Arctic surface microlayer

NASA Astrophysics Data System (ADS)

Gao, Q.; Leck, C.; Rauschenberg, C.; Matrai, P. A.

2012-07-01

The surface microlayer (SML) represents a unique system of which the physicochemical characteristics may differ from those of the underlying subsurface seawater (SSW). Within the Arctic pack ice area, the SML has been characterized as enriched in small colloids of biological origin, resulting from extracellular polymeric secretions (EPS). During the Arctic Summer Cloud Ocean Study (ASCOS) in August 2008, particulate organic matter (POM, with size range > 0.22 μm) and dissolved organic matter (DOM, < 0.22 μm, obtained after filtration) samples were collected and chemically characterized from the SML and the corresponding SSW at an open lead centered at 87.5° N and 5° E. Total organic carbon was persistently enriched in the SML with a mean enrichment factor (EF) of 1.45 ± 0.41, whereas sporadic depletions of dissolved carbohydrates and amino acids were observed. Monosaccharide compositional analysis reveals that EPS in the Arctic lead was formed mainly of distinctive heteropolysaccharides, enriched in xylose, fucose and glucose. The mean concentrations of total hydrolysable neutral sugars in SSW were 94.9 ± 37.5 nM in high molecular weight (HMW) DOM (> 5 kDa) and 64.4 ± 14.5 nM in POM. The enrichment of polysaccharides in the SML appeared to be a common feature, with EFs ranging from 1.7 to 7.0 for particulate polysaccharides and 3.5 to 12.1 for polysaccharides in the HMW DOM fraction. A calculated monosaccharide yield suggests that polymers in the HMW DOM fraction were scavenged, without substantial degradation, into the SML. Bubble scavenging experiments showed that newly aggregated particles could be formed abiotically by coagulation of low molecular weight nanometer-sized gels. Aerosol particles, artificially generated by bubbling experiments, were enriched in polysaccharides by factors of 22-70, relative to the source seawater. We propose that bubble scavenging of surface-active polysaccharides could be one of the possible mechanisms for the enrichment of polysaccharides in the high Arctic open lead SML.

On the chemical dynamics of extracellular polysaccharides in the high Arctic surface microlayer

NASA Astrophysics Data System (ADS)

Gao, Q.; Leck, C.; Rauschenberg, C.; Matrai, P. A.

2012-01-01

The surface microlayer (SML) represents a unique system of which the physicochemical characteristics may differ from those of the underlying subsurface seawater (SSW). Within the Arctic pack ice area, the SML has been characterized as enriched in small colloids of biological origin, resulting from extracellular polymeric secretions (EPS). During the Arctic Summer Cloud-Ocean Study (ASCOS) in August 2008, particulate and dissolved organic matter (POM, DOM) samples were collected and chemically characterized from the SML and the corresponding SSW at an open lead centered at 87.5° N and 5° E. Total organic carbon was persistently enriched in the SML with a mean enrichment factor (EF) of 1.45 ± 0.41, whereas sporadic depletions of dissolved carbohydrates and amino acids were observed. Monosaccharide compositional analysis reveals that EPS in the Arctic lead was formed mainly of distinctive heteropolysaccharides, enriched in xylose, fucose and glucose. The mean concentrations of total hydrolysable neutral sugars in SSW were 94.9 ± 37.5 nM in high molecular weight (HMW) DOM and 64.4 ± 14.5 nM in POM. The enrichment of polysaccharides in the SML appeared to be a common feature, with EFs ranging from 1.7 to 7.0 for particulate polysaccharides and 3.5 to 12.1 for polysaccharides in the HMW DOM fraction. A calculated monosaccharide yield suggests that polymers in the HMW DOM fraction were scavenged, without substantial degradation, into the SML. Bubble scavenging experiments showed that newly aggregated particles could be formed abiotically by coagulation of low molecular weight nanometer-sized gels. Experimentally-generated aerosol particles were enriched in polysaccharides by factors of 22-70, relative to the source seawater. We propose that bubble scavenging of surface-active polysaccharides was one of the possible mechanisms for the enrichment of polysaccharides in the SML.

A new organic reference material, L-glutamic acid, USGS41a, for δ13C and δ15N measurements − a replacement for USGS41

USGS Publications Warehouse

Qi, Haiping; Coplen, Tyler B.; Mroczkowski, Stanley J.; Brand, Willi A.; Brandes, Lauren; Geilmann, Heike; Schimmelmann, Arndt

2016-01-01

RationaleThe widely used l-glutamic acid isotopic reference material USGS41, enriched in both 13C and 15N, is nearly exhausted. A new material, USGS41a, has been prepared as a replacement for USGS41.MethodsUSGS41a was prepared by dissolving analytical grade l-glutamic acid enriched in 13C and 15N together with l-glutamic acid of normal isotopic composition. The δ13C and δ15N values of USGS41a were directly or indirectly normalized with the international reference materials NBS 19 calcium carbonate (δ13CVPDB = +1.95 mUr, where milliurey = 0.001 = 1 ‰), LSVEC lithium carbonate (δ13CVPDB = −46.6 mUr), and IAEA-N-1 ammonium sulfate (δ15NAir = +0.43 mUr) and USGS32 potassium nitrate (δ15N = +180 mUr exactly) by on-line combustion, continuous-flow isotope-ratio mass spectrometry, and off-line dual-inlet isotope-ratio mass spectrometry.ResultsUSGS41a is isotopically homogeneous; the reproducibility of δ13C and δ15N is better than 0.07 mUr and 0.09 mUr, respectively, in 200-μg amounts. It has a δ13C value of +36.55 mUr relative to VPDB and a δ15N value of +47.55 mUr relative to N2 in air. USGS41 was found to be hydroscopic, probably due to the presence of pyroglutamic acid. Experimental results indicate that the chemical purity of USGS41a is substantially better than that of USGS41.ConclusionsThe new isotopic reference material USGS41a can be used with USGS40 (having a δ13CVPDB value of −26.39 mUr and a δ15NAir value of −4.52 mUr) for (i) analyzing local laboratory isotopic reference materials, and (ii) quantifying drift with time, mass-dependent isotopic fractionation, and isotope-ratio-scale contraction for isotopic analysis of biological and organic materials. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.

A new organic reference material, l-glutamic acid, USGS41a, for δ(13) C and δ(15) N measurements - a replacement for USGS41.

PubMed

Qi, Haiping; Coplen, Tyler B; Mroczkowski, Stanley J; Brand, Willi A; Brandes, Lauren; Geilmann, Heike; Schimmelmann, Arndt

2016-04-15

The widely used l-glutamic acid isotopic reference material USGS41, enriched in both (13) C and (15) N, is nearly exhausted. A new material, USGS41a, has been prepared as a replacement for USGS41. USGS41a was prepared by dissolving analytical grade l-glutamic acid enriched in (13) C and (15) N together with l-glutamic acid of normal isotopic composition. The δ(13) C and δ(15) N values of USGS41a were directly or indirectly normalized with the international reference materials NBS 19 calcium carbonate (δ(13) CVPDB = +1.95 mUr, where milliurey = 0.001 = 1 ‰), LSVEC lithium carbonate (δ(13) CVPDB = -46.6 mUr), and IAEA-N-1 ammonium sulfate (δ(15) NAir = +0.43 mUr) and USGS32 potassium nitrate (δ(15) N = +180 mUr exactly) by on-line combustion, continuous-flow isotope-ratio mass spectrometry, and off-line dual-inlet isotope-ratio mass spectrometry. USGS41a is isotopically homogeneous; the reproducibility of δ(13) C and δ(15) N is better than 0.07 mUr and 0.09 mUr, respectively, in 200-μg amounts. It has a δ(13) C value of +36.55 mUr relative to VPDB and a δ(15) N value of +47.55 mUr relative to N2 in air. USGS41 was found to be hydroscopic, probably due to the presence of pyroglutamic acid. Experimental results indicate that the chemical purity of USGS41a is substantially better than that of USGS41. The new isotopic reference material USGS41a can be used with USGS40 (having a δ(13) CVPDB value of -26.39 mUr and a δ(15) NAir value of -4.52 mUr) for (i) analyzing local laboratory isotopic reference materials, and (ii) quantifying drift with time, mass-dependent isotopic fractionation, and isotope-ratio-scale contraction for isotopic analysis of biological and organic materials. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA. Published in 2016. This article is a U.S. Government work and is in the public domain in the USA.

Metamorphosis alters contaminants and chemical tracers in insects: implications for food webs

USGS Publications Warehouse

Kraus, Johanna M.; Walters, David M.; Wesner, Jeff S.; Stricker, Craig A.; Schmidt, Travis S.; Zuellig, Robert E.

2014-01-01

Insects are integral to most freshwater and terrestrial food webs, but due to their accumulation of environmental pollutants they are also contaminant vectors that threaten reproduction, development, and survival of consumers. Metamorphosis from larvae to adult can cause large chemical changes in insects, altering contaminant concentrations and fractionation of chemical tracers used to establish contaminant biomagnification in food webs, but no framework exists for predicting and managing these effects. We analyzed data from 39 studies of 68 analytes (stable isotopes and contaminants), and found that metamorphosis effects varied greatly. δ15N, widely used to estimate relative trophic position in biomagnification studies, was enriched by 1‰ during metamorphosis, while δ13C used to estimate diet, was similar in larvae and adults. Metals and polycyclic aromatic hydrocarbons (PAHs) were predominantly lost during metamorphosis leading to 2 to 125-fold higher larval concentrations and higher exposure risks for predators of larvae compared to predators of adults. In contrast, manufactured organic contaminants (such as polychlorinated biphenyls) were retained and concentrated in adults, causing up to 3-fold higher adult concentrations and higher exposure risks to predators of adult insects. Both food web studies and contaminant management and mitigation strategies need to consider how metamorphosis affects the movement of materials between habitats and ecosystems, with special regard for aquatic-terrestrial linkages.

Witwatersrand gold deposits formed by volcanic rain, anoxic rivers and Archaean life

NASA Astrophysics Data System (ADS)

Heinrich, Christoph A.

2015-03-01

The Witwatersrand Basin in South Africa is one of the best-preserved records of fluvial sedimentation on an Archaean continent. The basin hosts the worlds biggest gold resource in thin pebble beds, but the process for gold enrichment is debated. Mechanical accumulation of gold particles from flowing river water is the prevailing hypothesis, yet there is evidence for hydrothermal mobilization of gold by fluids invading the metasedimentary rocks after their burial. Earth's atmosphere three billion years ago was oxygen free, but already sustained some of the oldest microbial life on land. Here I use thermodynamic modelling and mass-balance calculations to show that these conditions could have led to the chemical transport and precipitation of gold in anoxic surface waters, reconciling the evidence for fluvial deposition with evidence for hydrothermal-like chemical reactions. I suggest that the release of sulphurous gases from large volcanic eruptions created acid rain that enabled the dissolution and transport of gold in surface waters as sulphur complexes. Precipitation of the richest gold deposits could have been triggered by chemical reduction of the dissolved gold onto organic material in shallow lakes and pools. I conclude that the Witwatersrand gold could have formed only during the Archaean, after the emergence of continental life but before the rise of oxygen in the Earth's atmosphere.

Enrichment of Sc2O3 and TiO2 from bauxite ore residues.

PubMed

Deng, Bona; Li, Guanghui; Luo, Jun; Ye, Qing; Liu, Mingxia; Peng, Zhiwei; Jiang, Tao

2017-06-05

As a major byproduct generated in the alumina industry, bauxite ore residue is an important reserve of scandium and titanium. In this study, the feasibility and mechanism of enriching Sc 2 O 3 and TiO 2 from a non-magnetic material, which was obtained from carbothermal reductive roasting and magnetic separation of bauxite ore residue, were investigated based on a two-step (acidic and alkali) leaching process. It was revealed that approximately 78% SiO 2 and 30-40% of CaO, FeO and Al 2 O 3 were removed from a non-magnetic material with 0.0134wt.% Sc 2 O 3 and 7.64wt.% TiO 2 by phosphoric acidic leaching, while about 95% Al 2 O 3 and P 2 O 5 were further leached by subsequent sodium hydroxide leaching of the upper-stream leach residue. A Sc 2 O 3 -, TiO 2 - rich material containing 0.044wt.% Sc 2 O 3 and 25.5wt.% TiO 2 was obtained, the recovery and the enrichment factor of Sc 2 O 3 and TiO 2 were about 85% and 5, respectively. The enrichment of Sc 2 O 3 was attributed to higher pH (>3.3) of phosphoric acid solution than its dissolution pH 0 , and the enrichment of TiO 2 was mainly associated with the insoluble perovskite (CaTiO 3 ) in the acidic solution at ambient temperature. As Sc 2 O 3 and TiO 2 cannot be dissolved in the alkali solution, they were further enriched in the leach residue. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical variations observed on Aeolis Mons in Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Frydenvang, Jens; Gasda, Patrick J.; Thompson, Lucy; Hurowitz, Joel; Grotzinger, John P.; Blaney, Diana L.; Gellert, Ralf; Wiens, Roger; Vasavada, Ashwin R.; MSL Science Team

2016-10-01

The extraordinarily extensive exposure of hematite-, clay-, sulfate-bearing stratigraphic layers in the lower part of Aeolis Mons was the primary reason Gale Crater was selected as the landing site for the Mars Science Laboratory rover, Curiosity. 753 martian solar days (sols) after the Curiosity rover landed in Gale Crater in August 2012, and after driving more than 9 km, the Curiosity rover arrived at the first exposure of the Murray formation, the basal layer of Aeolis Mons. The Murray formation is a thinly laminated lacustrine mudstone showing stratification down to the millimeter scale. This supports the idea that the stratigraphic layers of Aeolis Mons are sedimentary, and likely deposited in a series of long-lived lakes extending into the early Hesperian time, as recently described by Grotzinger et al. (Science, vol. 350, 2015). The chemical variations observed throughout the Murray formation by the ChemCam and APXS instruments in the 600+ sols since first arriving at Aeolis Mons will be presented. While Murray remains thinly laminated throughout the 30+ vertical meters of stratigraphy explored, large chemical variations are observed. The most extreme variations arise from likely co-located detrital and diagenetic silica enrichments in Murray. Remarkably, an associated diagenetic silica enrichment is also observed in the unconformably overlying eolian sandstone of the Stimson formation in that location. The detrital enrichment provides evidence of how the source region chemistry varied as the sedimentary layers of Aeolis Mons were deposited. Conversely, the diagenetic enrichment observed across both the Murray and Stimson formations provides compelling evidence for the presence of subsurface fluids in Gale Crater, thousands to millions of years after the crater lakes disappeared. This evidence of liquid water greatly extends the timescale in which Gale Crater might have been habitable.

Nutrient uptake and growth responses of Virginia pine to elevated atmospheric carbon dioxide. [Pisolithus tinctorius, Pinus virginiana Mill

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luxmoore, R.J.; O'Neill, E.G.; Ells, J.M.

One-year-old Virgina pine (Pinus virginiana Mill.) seedlings with native or Pisolithus tinctorius mycorrhizal associations were grown in pots with soil low in organic matter and in cation exchange capacity and were exposed to one of five atmospheric CO/sub 2/ levels in the range of 340 to 940 ..mu..L/L in open-top field chambers. The mean dry weight of the seedlings increased from 4.4 to 11.0 g/plant during the 122-d exposure period. Significant increases in dry weight and uptake of N, Ca, Al, Fe, Zn, and Sr occurred with CO/sub 2/ enrichment. Greater chemical uptake was associated with greater root weight. Specificmore » absorption rates for chemicals (uptake per gram of root per day) were generally not affected by CO/sub 2/ enrichment. The uptake of P and K was not increased with elevated CO/sub 2/, and these elements showed the greater nutrient-use efficiency (C gain per element uptake). The nutrient-use efficiency for N and Ca was not influenced by atmospheric CO/sub 2/ enrichment. Large increases in Zn uptake at high CO'' suggested an increase in rhizosphere acidification, which may have resulted from the release of protons from the roots, since it was estimated that cation uptake increasingly exceeded anion uptake with CO/sub 2/ enrichment. Potassium, P, and NO/sub 3//sup -/ concentrations in the pot leachate decreased with higher CO/sub 2/ levels, and a similar trend was found for Al and Mg. These results suggest that soil-plant systems may exhibit increased nutrient and chemical retention at elevated atmospheric CO/sub 2/.« less

Potassium isotopic evidence for a high-energy giant impact origin of the Moon.

PubMed

Wang, Kun; Jacobsen, Stein B

2016-10-27

The Earth-Moon system has unique chemical and isotopic signatures compared with other planetary bodies; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as potassium compared with the Earth and the bulk solar composition, and it has long been thought to be the result of a catastrophic Moon-forming giant impact event. Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy potassium isotopes during the loss of volatiles; however such enrichment was never found. Here we report new high-precision potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2σ) enriched in the heavy isotopes of potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model, but supports the high-energy, high-angular-momentum giant impact model for the origin of the Moon. High-precision potassium isotope data can also be used as a 'palaeo-barometer' to reveal the physical conditions during the Moon-forming event.

Provenance, Source Rock Characteristics And Paleoweathering Conditions Of The Nearshore Continental Sediments Off Pondicherry, South East Coast Of India

NASA Astrophysics Data System (ADS)

Natarajan, T.; Seshachalam, S.; Ponniah, J.; Varadhan, R.; M, S.

2008-05-01

Geochemical studies, comprising major elements and trace elements, including the Rare Earth Elements (REE), have been carried out on the modern sediments of inner continental shelf representing nearshore marine environments. Concentrations were normalized with Chondrite and PAAS show LREE enriched and flat HREE patterns with slight positive Eu anomaly which is due to the influence of feldspar rich source materials. The LREE enriched and flat HREE patterns with positive Eu anomaly have been considered as the typical character of post- Archaean Sediments. The La/Th ratio ranges from 1.66 to 8.84 with an average value of 4.09, which indicates a heterogenitic source for the sediments of the study area. The La-Th-Sc ternary plot suggests all the samples fall close to the field dominated by tonalite to granite and away from the basalt and komatiite compositions and appear to be derived from sources enriched in felsic components. The transition metal ratios such as Cr/V, Ni/CO and V/Ni indicate both Archaean and Post-Archaean nature to the sediments indicating that the sediments have been derived from heterogenitic sources. The ternary diagram plot of Th-Hf-Co and La-Th-Sc falls in the field of upper continental crust of post Archaean age. This clearly indicates the terrestrial source for the sediments from the nearby landmass. The data are slightly offset from the upper crustal composition away from the Hf apex. This is probably a result of Zircon concentration. Geochemical data have also helped in ascertaining the weathering trends. The Chemical Index of Alteration (CIA) has been used to quantify the degree of weathering. The calculated CIA values for sediments demonstrate both low CIA values of less than 50 percent (low silicate weathering) and intermediate CIA values (60-70 percent) indicating that the sediments are possibly the product of sedimentary and metasedimentary rocks that have undergone intermediate chemical weathering. On an A—CN—K diagram, the data fall closer to the trend parallel to Al2O3 (CaO*+Na2O) join, suggesting that the sediments represent weathered products from granite and charnockite.

Curiosity at Gale Crater's Hematite Ridge: High Mn and P Near the Ridge Show Chemical Evidence for Generation by an Oxidation Front

NASA Astrophysics Data System (ADS)

Wiens, R. C.; Meslin, P. Y.; Lanza, N.; Frydenvang, J.; Mangold, N.; Johnson, J. R.; Fraeman, A. A.; Horgan, B.; Bedford, C.; Blaney, D. L.; Bridges, J.; Cousin, A.; Ehlmann, B. L.; Forni, O.; Gasda, P. J.; Gasnault, O.; Gellert, R.; Johnstone, S.; Lamm, S. N.; Lasue, J.; Le Mouelic, S.; Maurice, S.; Newsom, H. E.; Ollila, A.; Payre, V.; Rapin, W.; Salvatore, M. R.; Schwenzer, S. P.; Thomas, N. H.; Vasavada, A. R.

2017-12-01

After traversing >17 km, the Curiosity rover has reached Vera Rubin Ridge (VRR), formerly known as the Hematite Ridge. Situated 200 m above the base of Gale crater on the slope of Mt. Sharp, VRR was one of the original objectives of the mission. VRR stretches 6.5 km NE-SW with a vertical height of 30 m (to -4200 m), it is the largest surface feature encountered by Curiosity to date. Orbital observation by CRISM of relatively strong hematite signal along the ridge gave it its original name. Some hematite spectral signatures along the ridge have been observed by Curiosity from long distance by Mastcam and ChemCam passive spectra. Curiosity started observing local enrichments of hematite in Murray lacustrine sediments near Bagnold Dunes, which may or may not be related to the hematite observed on the ridge top. The presence of hematite-like spectral signatures became variable as the rover approached below the ridge. Chemistry and ridge imaging: Magnesium, Mn, and P have shown strong increases in dark surface features in some regions below the ridge. Manganese oxide abundances have risen to >10 wt. % in some dark nodules and laminae. Iron, Mg, and P appear correlated in high-P observations, with the highest values associated with vein-related inclusions. Another class of dark features shows high Fe without high Mn or P. ChemCam high-resolution imaging from within 100 m of the base of the ridge shows regions of both finely laminated parallel strata and low-angle cross stratification along with vertical fractures surrounded by alteration halos; these are comparable to Murray stratigraphy. Given that the exposed surface of the Murray formation is the result of significant erosional deflation, the ridge must be more erosionally resistant than the surrounding material. The observation of high-oxidation-potential element enrichments below VRR argues for an oxidation front in which the local sediments were enriched in oxidized iron (hematite) and manganese. In this presentation we will report on the latest geochemical trends leading up to and on VRR, comparing chemical and morphological observations to observed mineralogy.

Recycling coffee grounds and tea leaf wastes to improve the yield and mineral content of grains of paddy rice.

PubMed

Morikawa, Claudio K; Saigusa, M

2011-08-30

Coffee grounds and tea leaf wastes exhibit strong affinity for metals such as Fe and Zn. The objective of this experiment was to evaluate the effect of top-dressing application of Fe- and Zn-enriched coffee grounds and tea leaf wastes at the panicle initiation stage on the mineral content of rice grains and the yield of paddy rice. The Fe and Zn contents of brown rice grains increased significantly on application of both coffee and tea waste materials. The concentration of Mn was increased by top-dressing application of coffee waste material only. For Cu, no significant (P < 0.05) differences were found between the control and ferrous sulfate/zinc sulfate treatment. The application of coffee and tea waste materials led to a significant (P < 0.05) increase in the number of grains per panicle, which was reflected in increases in the total number of grains per hill and in grain yield. The top-dressing application of these materials is an excellent method to recycle coffee grounds and tea wastes from coffee shops. Use of these novel materials would not only reduce the waste going to landfill but would also benefit the mineral nutrition of rice consumers at low cost by increasing Fe and Zn levels of rice grains as well as grain yield. Copyright © 2011 Society of Chemical Industry.

Room-temperature synthesis of core-shell structured magnetic covalent organic frameworks for efficient enrichment of peptides and simultaneous exclusion of proteins.

PubMed

Lin, Guo; Gao, Chaohong; Zheng, Qiong; Lei, Zhixian; Geng, Huijuan; Lin, Zian; Yang, Huanghao; Cai, Zongwei

2017-03-28

Core-shell structured magnetic covalent organic frameworks (Fe 3 O 4 @COFs) were synthesized via a facile approach at room temperature. Combining the advantages of high porosity, magnetic responsiveness, chemical stability and selectivity, Fe 3 O 4 @COFs can serve as an ideal absorbent for the highly efficient enrichment of peptides and the simultaneous exclusion of proteins from complex biological samples.

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamicmore » fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device ( 235U/ 238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO 2 is found to be relatively invariable across the samples and interfaces (~3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. Lastly, these fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.« less

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

NASA Astrophysics Data System (ADS)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; Knight, Kim B.; Isselhardt, Brett H.; Matzel, Jennifer E.; Weber, Peter K.; Prussin, Stan G.; Hutcheon, Ian D.

2017-03-01

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device (235U/238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO2 is found to be relatively invariable across the samples and interfaces (∼3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. These fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

DOE PAGES

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; ...

2016-10-29

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamicmore » fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device ( 235U/ 238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO 2 is found to be relatively invariable across the samples and interfaces (~3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. Lastly, these fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.« less

Study of Chemical Changes in Uranium Oxyfluoride Particles Progress Report March - October 2009

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kips, R; Kristo, M; Hutcheon, I

2009-11-22

Nuclear forensics relies on the analysis of certain sample characteristics to determine the origin and history of a nuclear material. In the specific case of uranium enrichment facilities, it is the release of trace amounts of uranium hexafluoride (UF{sub 6}) gas - used for the enrichment of uranium - that leaves a process-characteristic fingerprint. When UF{sub 6} gas interacts with atmospheric moisture, uranium oxyfluoride particles or particle agglomerates are formed with sizes ranging from several microns down to a few tens of nanometers. These particles are routinely collected by safeguards organizations, such as the International Atomic Energy Agency (IAEA), allowingmore » them to verify whether a facility is compliant with its declarations. Spectrometric analysis of uranium particles from UF{sub 6} hydrolysis has revealed the presence of both particles that contain fluorine, and particles that do not. It is therefore assumed that uranium oxyfluoride is unstable, and decomposes to form uranium oxide. Understanding the rate of fluorine loss in uranium oxyfluoride particles, and the parameters that control it, may therefore contribute to placing boundaries on the particle's exposure time in the environment. Expressly for the purpose of this study, we prepared a set of uranium oxyfluoride particles at the Institute for Reference Materials and Measurements (EU-JRC-IRMM) from a static release of UF{sub 6} in a humid atmosphere. The majority of the samples was stored in controlled temperature, humidity and lighting conditions. Single particles were characterized by a suite of micro-analytical techniques, including NanoSIMS, micro-Raman spectrometry (MRS), scanning (SEM) and transmission (TEM) electron microscopy, energy-dispersive X-ray spectrometry (EDX) and focused ion beam (FIB). The small particle size was found to be the main analytical challenge. The relative amount of fluorine, as well as the particle chemical composition and morphology were determined at different stages in the ageing process, and immediately after preparation. This report summarizes our most recent findings for each of the analytical techniques listed above, and provides an outlook on what remains to be resolved. Additional spectroscopic and mass spectrometric measurements were carried out at Pacific Northwest National Laboratory, but are not included in this summary.« less

Oxygen Abundances in the Rings of Polar-Ring Galaxies

NASA Astrophysics Data System (ADS)

Radtke, I. R.; Eskridge, P. B.; Pogge, R. W.

2003-05-01

Polar ring galaxies (PRGs) are typically early-type (S0 or E) galaxies surrounded by rings of gas, dust, and stars orbiting nearly perpendicular to the principle plane of the host galaxy (Whitmore et al. 1990 AJ 100 1489). Given that PRGs have two separate, perpendicular axes of rotation, it is clear on dynamical grounds that PRGs are the products of merger events between two galaxies, but are observed in a state where two distinct kinematic and morphological structures are still apparent. As such, they present a unique opportunity to study merger events in systems where the debris is not confused with material from the host. Our understanding of the relative importance of polar ring systems in the overall process of galaxy evolution is confounded by our lack of knowledge regarding the typical lifetimes and evolutionary histories of polar rings. A crucial factor for understanding the formation and evolution of PRGs is information regarding the elemental abundances of the ring material. Polar rings are typically rich in {\\protectH 2} regions. Optical spectroscopy of these {\\protectH 2} regions can tell us their density, temperature, and oxygen abundance. Our earlier work (Eskridge & Pogge 1997 ApJ 486 259) revealed roughly Solar oxygen abundances for {\\protectH 2} regions in the polar ring of NGC 2685. We have extended this project, and now have spectra for six PRGs. Analysis of the data for II Zw 73 and UGC 7576 reveal the polar rings of these galaxies to have {\\protectH 2} region oxygen abundances in the range 0.3 to 0.6 Solar, substantially less than found for NGC 2685. Abundances in this range are much easier to explain with conventional models of chemical enrichment and polar ring formation. We shall present results for our full sample. Taken as a whole, this sample will provide a clear foundation for the typical chemical enrichment patterns in polar rings, and thus provide a clearer understanding of the formation and evolution of these curious objects. We gratefully acknowledge financial support for this project from the AAS Small Research Grant program, and from a Minnesota State University Faculty Research Grant awarded to P. Eskridge.

Production and separation of 43Sc for radiopharmaceutical purposes.

PubMed

Domnanich, Katharina A; Eichler, Robert; Müller, Cristina; Jordi, Sara; Yakusheva, Vera; Braccini, Saverio; Behe, Martin; Schibli, Roger; Türler, Andreas; van der Meulen, Nicholas P

2017-01-01

The favorable decay properties of 43 Sc and 44 Sc for PET make them promising candidates for future applications in nuclear medicine. An advantage 43 Sc (T 1/2 = 3.89 h, Eβ + av = 476 keV [88%]) exhibits over 44 Sc, however, is the absence of co-emitted high energy γ-rays. While the production and application of 44 Sc has been comprehensively discussed, research concerning 43 Sc is still in its infancy. This study aimed at developing two different production routes for 43 Sc, based on proton irradiation of enriched 46 Ti and 43 Ca target material. 43 Sc was produced via the 46 Ti(p,α) 43 Sc and 43 Ca(p,n) 43 Sc nuclear reactions, yielding activities of up to 225 MBq and 480 MBq, respectively. 43 Sc was chemically separated from enriched metallic 46 Ti (97.0%) and 43 CaCO 3 (57.9%) targets, using extraction chromatography. In both cases, ~90% of the final activity was eluted in a small volume of 700 μL, thereby, making it suitable for direct radiolabeling. The prepared products were of high radionuclidic purity, i.e. 98.2% 43 Sc were achieved from the irradiation of 46 Ti, whereas the product isolated from irradiated 43 Ca consisted of 66.2% 43 Sc and 33.3% 44 Sc. A PET phantom study performed with 43 Sc, via both nuclear reactions, revealed slightly improved resolution over 44 Sc. In order to assess the chemical purity of the separated 43 Sc, radiolabeling experiments were performed with DOTANOC, attaining specific activities of 5-8 MBq/nmol, respectively, with a radiochemical yield of >96%. It was determined that higher 43 Sc activities were accessible via the 43 Ca production route, with a comparatively less complex target preparation and separation procedure. The product isolated from irradiated 46 Ti, however, revealed purer 43 Sc with minor radionuclidic impurities. Based on the results obtained herein, the 43 Ca route features some advantages (such as higher yields and direct usage of the purchased target material) over the 46 Ti path when aiming at 43 Sc production on a routine basis.

Nickel container of highly-enriched uranium bodies and sodium

DOEpatents

Zinn, Walter H.

1976-01-01

A fuel element comprises highly a enriched uranium bodies coated with a nonfissionable, corrosion resistant material. A plurality of these bodies are disposed in layers, with sodium filling the interstices therebetween. The entire assembly is enclosed in a fluid-tight container of nickel.

Thermal breeder fuel enrichment zoning

DOEpatents

Capossela, Harry J.; Dwyer, Joseph R.; Luce, Robert G.; McCoy, Daniel F.; Merriman, Floyd C.

1992-01-01

A method and apparatus for improving the performance of a thermal breeder reactor having regions of higher than average moderator concentration are disclosed. The fuel modules of the reactor core contain at least two different types of fuel elements, a high enrichment fuel element and a low enrichment fuel element. The two types of fuel elements are arranged in the fuel module with the low enrichment fuel elements located between the high moderator regions and the high enrichment fuel elements. Preferably, shim rods made of a fertile material are provided in selective regions for controlling the reactivity of the reactor by movement of the shim rods into and out of the reactor core. The moderation of neutrons adjacent the high enrichment fuel elements is preferably minimized as by reducing the spacing of the high enrichment fuel elements and/or using a moderator having a reduced moderating effect.

Optimization of ISOCS Parameters for Quantitative Non-Destructive Analysis of Uranium in Bulk Form

NASA Astrophysics Data System (ADS)

Kutniy, D.; Vanzha, S.; Mikhaylov, V.; Belkin, F.

2011-12-01

Quantitative calculation of the isotopic masses of fissionable U and Pu is important for forensic analysis of nuclear materials. γ-spectrometry is the most commonly applied tool for qualitative detection and analysis of key radionuclides in nuclear materials. Relative isotopic measurement of U and Pu may be obtained from γ-spectra through application of special software such as MGAU (Multi-Group Analysis for Uranium, LLNL) or FRAM (Fixed-Energy Response Function Analysis with Multiple Efficiency, LANL). If the concentration of U/Pu in the matrix is unknown, however, isotopic masses cannot be calculated. At present, active neutron interrogation is the only practical alternative for non-destructive quantification of fissionable isotopes of U and Pu. An active well coincidence counter (AWCC), an alternative for analyses of uranium materials, has the following disadvantages: 1) The detection of small quantities (≤100 g) of 235U is not possible in many models; 2) Representative standards that capture the geometry, density and chemical composition of the analyzed unknown are required for precise analysis; and 3) Specimen size is severely restricted by the size of the measuring chamber. These problems may be addressed using modified γ-spectrometry techniques based on a coaxial HPGe-detector and ISOCS software (In Situ Object Counting System software, Canberra). We present data testing a new gamma-spectrometry method uniting actinide detection with commonly utilized software, modified for application in determining the masses of the fissionable isotopes in unknown samples of nuclear materials. The ISOCS software, widely used in radiation monitoring, calculates the detector efficiency curve in a specified geometry and range of photon energies. In describing the geometry of the source-detector, it is necessary to clearly describe the distance between the source and the detector, the material and the thickness of the walls of the container, as well as material, density and chemical composition of the matrix of the specimen. Obviously, not all parameters can be characterized when measuring samples of unknown composition or uranium in bulk form. Because of this, and especially for uranium materials, the IAEA developed an ISOCS optimization procedure. The target values for the optimization are Μmatrixfixed, the matrix mass determined by weighing with a known mass container, and Εfixed, the 235U enrichment, determined by MGAU. Target values are fitted by varying the matrix density (ρ), and the concentration of uranium in the matrix of the unknown (w). For each (ρi, wi), an efficiency curve is generated, and the masses of uranium isotopes, Μ235Ui and Μ238Ui, determined using spectral activity data and known specific activities for U. Finally, fitted parameters are obtained for Μmatrixi = Μmatrixfixed ± 1σ, Εi = Εfixed ± 1σ, as well as important parameters (ρi, wi, Μ235Ui, Μ238Ui, ΜUi). We examined multiple forms of uranium (powdered, pressed, and scrap UO2 and U3O8) to test this method for its utility in accurately identifying the mass and enrichment of uranium materials, and will present the results of this research.

Effect of mining and related activities on the sediment trace element geochemistry of Lake Coeur D'Alene, Idaho, USA. Part I: Surface sediments

USGS Publications Warehouse

Horowitz, Arthur J.; Elrick, Kent A.; Cook, Robert B.

1993-01-01

During the summer of 1989 surface sediment samples were collected in Lake Coeur d'Alene, the Coeur d'Alene River and the St Joe River, Idaho, at a density of approximately one sample per square kilometre. Additional samples were collected from the banks of the South Fork of the Coeur d'Alene and the Coeur d'Alene Rivers in 1991. All the samples were collected to determine trace element concentrations, partitioning and distribution patterns, and to relate them to mining, mining related and discharge operations that have occurred in the Coeur d'Alene district since the 1880s, some of which are ongoing.Most of the surface sediments in Lake Coeur d'Alene north of Conkling Point and Carey Bay are substantially enriched in Ag, As, Cu, Cd, Hg, Pb, Sb and Zn relative to unaffected sediments in the southern portion of the lake near the St Joe River. All the trace element enriched sediments are extremely fine grained (mean grain sizes « 63 μm). Most of the enriched trace elements, based on both the chemical analyses of separated heavy and light mineral fractions and a two step sequential extraction procedure, are associated with an operationally defined Fe oxide phase; much smaller percentages are associated either with operationally defined organics/sulphides or refractory phases.The presence, concentration and distribution of the Fe oxides and heavy minerals indicates that a substantial portion of the enriched trace elements are probably coming from the Coeur d'Alene River, which is serving as a point source. Within the lake, this relatively simple point source pattern is complicated by a combination of (1) the formation of trace element rich authigenic Fe oxides that appear to have reprecipitated from material solubilized from anoxic bed sediments and (2) physical remobilization by currents and wind driven waves. The processes that have caused the trace element enrichment in the surface sediments of Lake Coeur d'Alene are likely to continue for the foreseeable future.

BiNChE: a web tool and library for chemical enrichment analysis based on the ChEBI ontology.

PubMed

Moreno, Pablo; Beisken, Stephan; Harsha, Bhavana; Muthukrishnan, Venkatesh; Tudose, Ilinca; Dekker, Adriano; Dornfeldt, Stefanie; Taruttis, Franziska; Grosse, Ivo; Hastings, Janna; Neumann, Steffen; Steinbeck, Christoph

2015-02-21

Ontology-based enrichment analysis aids in the interpretation and understanding of large-scale biological data. Ontologies are hierarchies of biologically relevant groupings. Using ontology annotations, which link ontology classes to biological entities, enrichment analysis methods assess whether there is a significant over or under representation of entities for ontology classes. While many tools exist that run enrichment analysis for protein sets annotated with the Gene Ontology, there are only a few that can be used for small molecules enrichment analysis. We describe BiNChE, an enrichment analysis tool for small molecules based on the ChEBI Ontology. BiNChE displays an interactive graph that can be exported as a high-resolution image or in network formats. The tool provides plain, weighted and fragment analysis based on either the ChEBI Role Ontology or the ChEBI Structural Ontology. BiNChE aids in the exploration of large sets of small molecules produced within Metabolomics or other Systems Biology research contexts. The open-source tool provides easy and highly interactive web access to enrichment analysis with the ChEBI ontology tool and is additionally available as a standalone library.

Grain boundary diffusion studied on nano scale by rim growth experiments with isotopically doped thin films

NASA Astrophysics Data System (ADS)

Milke, R.; Dohmen, R.; Wiedenbeck, M.; Wirth, R.; Abart, R.; Becker, H.-W.

2003-04-01

Grain boundary diffusion studies by the rim growth method in the system MgO(±FeO)-SiO_2 have evolved from measuring rim growth rates to the tracing of chemical components by using isotopically enriched starting materials and SIMS analyses (Milke et al. 2001). We miniaturized this setup for grain boundary diffusion experiments by using pulsed-laser deposited (PLD) thin films (Dohmen et al. 2002). The starting samples consist of polycrystalline layers of pyroxene (en90fs10) and isotopically doped (18O, 29Si) olivine (fo90fa10) with a total thickness <= 1 μm on a polished quartz surface. A first series of experiments was performed at temperatures between 1000 and 1200^oC at fO_2 of 10-10 bar. Resulting layer thickness and chemi-cal composition were measured by Rutherford Back-Scattering (RBS) and TEM using Focused Ion Beam (FIB) preparation methods. O and Si isotope profiles were measured by SIMS depth scanning. The enstatite layers thicken during the annealing experiments with well-defined interfaces by rates for Δx^2 of 700 to 50000 nm^2/h at the chosen conditions. The iso-tope profiles show that Si acts as a slow diffusing component. From the enstatite growth rates a Dgb_Aδ can be calculated, where A is the rate-determining component. This gives a Dgb_Aδ in the range of 10-26 (at 1000^oC) to 10-24 (at 1200^oC) m^3s-1, which is well in accordance with an extrapolation from the data of Fisler et al. (1997) at 1350 to 1450^oC. This indicates that over the entire interval from 1000 to 1450^oC the reaction is controlled by diffusion of the same component and more importantly that mechanisms on the nano scale are the same as on the microscopic scale. The new method has several advantages over previously used techniques. The well-defined layers on nano scale allow one to study rim growth at lower temperatures than before and avoids therefore large extrapolations to natural conditions. The very small amount of isotopically enriched material needed for one sample makes it also economically viable. The samples can be designed with variable chemical composi-tions, e.g. distinct members of the fo-fa and en-fs series. The versatility of the PLD-technique allows one to apply this method to other chemical systems as well. Ref.: Dohmen et al. (2002) Eur J Miner 14: 1155--1168; Milke et al. (2001), Contrib Miner Petrol 142: 15--26; Fisler et al. (1997) Phys Chem Minerals 24: 264--273.

77 FR 39899 - Technical Corrections

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-06

..., Nuclear material, Oil and gas exploration--well logging, Reporting and recordkeeping requirements... recordkeeping requirements, Source material, Uranium. 10 CFR Part 50 Antitrust, Classified information, Criminal... measures, Special nuclear material, Uranium enrichment by gaseous diffusion. 10 CFR Part 81 Administrative...

Aeolian controls of soil geochemistry and weathering fluxes in high-elevation ecosystems of the Rocky Mountains, Colorado

USGS Publications Warehouse

Lawrence, Corey R.; Reynolds, Richard L.; Kettterer, Michael E.; Neff, Jason C.

2013-01-01

When dust inputs are large or have persisted for long periods of time, the signature of dust additions are often apparent in soils. The of dust will be greatest where the geochemical composition of dust is distinct from local sources of soil parent material. In this study the influence of dust accretion on soil geochemistry is quantified for two different soils from the San Juan Mountains of southwestern Colorado, USA. At both study sites, dust is enriched in several trace elements relative to local rock, especially Cd, Cu, Pb, and Zn. Mass-balance calculations that do not explicitly account for dust inputs indicate the accumulation of some elements in soil beyond what can be explained by weathering of local rock. Most observed elemental enrichments are explained by accounting for the long-term accretion of dust, based on modern isotopic and geochemical estimates. One notable exception is Pb, which based on mass-balance calculations and isotopic measurements may have an additional source at one of the study sites. These results suggest that dust is a major factor influencing the development of soil in these settings and is also an important control of soil weathering fluxes. After accounting for dust inputs in mass-balance calculations, Si weathering fluxes from San Juan Mountain soils are within the range observed for other temperate systems. Comparing dust inputs with mass-balanced based flux estimates suggests dust could account for as much as 50–80% of total long-term chemical weathering fluxes. These results support the notion that dust inputs may sustain chemical weathering fluxes even in relatively young continental settings. Given the widespread input of far-traveled dust, the weathering of dust is likely and important and underappreciated aspect of the global weathering engine.

Aeolian controls of soil geochemistry and weathering fluxes in high-elevation ecosystems of the Rocky Mountains, Colorado

NASA Astrophysics Data System (ADS)

Lawrence, Corey R.; Reynolds, Richard L.; Ketterer, Michael E.; Neff, Jason C.

2013-04-01

When dust inputs are large or have persisted for long periods of time, the signature of dust additions are often apparent in soils. The of dust will be greatest where the geochemical composition of dust is distinct from local sources of soil parent material. In this study the influence of dust accretion on soil geochemistry is quantified for two different soils from the San Juan Mountains of southwestern Colorado, USA. At both study sites, dust is enriched in several trace elements relative to local rock, especially Cd, Cu, Pb, and Zn. Mass-balance calculations that do not explicitly account for dust inputs indicate the accumulation of some elements in soil beyond what can be explained by weathering of local rock. Most observed elemental enrichments are explained by accounting for the long-term accretion of dust, based on modern isotopic and geochemical estimates. One notable exception is Pb, which based on mass-balance calculations and isotopic measurements may have an additional source at one of the study sites. These results suggest that dust is a major factor influencing the development of soil in these settings and is also an important control of soil weathering fluxes. After accounting for dust inputs in mass-balance calculations, Si weathering fluxes from San Juan Mountain soils are within the range observed for other temperate systems. Comparing dust inputs with mass-balanced based flux estimates suggests dust could account for as much as 50-80% of total long-term chemical weathering fluxes. These results support the notion that dust inputs may sustain chemical weathering fluxes even in relatively young continental settings. Given the widespread input of far-traveled dust, the weathering of dust is likely and important and underappreciated aspect of the global weathering engine.

Chemical characterization and sorption capacity measurements of degraded newsprint from a landfill

USGS Publications Warehouse

Chen, Lixia; Nanny, Mark A.; Knappe, Detlef R. U.; Wagner, Travis B.; Ratasuk, Nopawan

2004-01-01

Newsprint samples collected from 12−16 ft (top layer (TNP)), 20−24 ft (middle layer (MNP)), and 32−36 ft (bottom layer (BNP)) below the surface of the Norman Landfill (NLF) were characterized by infrared (IR) spectroscopy, cross-polarization, magic-angle spinning 13C nuclear magnetic resonance (CP-MAS 13C NMR) spectroscopy, and tetramethylammonium hydroxide (TMAH) thermochemolysis gas chromatography/mass spectrometry (GC/MS). The extent of NLF newsprint degradation was evaluated by comparing the chemical composition of NLF newsprint to that of fresh newsprint (FNP) and newsprint degraded in the laboratory under methanogenic conditions (DNP). The O-alkyl/alkyl, cellulose/lignin, and lignin/resin acid ratios showed that BNP was the most degraded, and that all three NLF newsprint samples were more degraded than DNP. 13C NMR and TMAH thermochemolysis data demonstrated selective enrichment of lignin over cellulose, and TMAH thermochemolysis further exhibited selective enrichment of resin acids over lignin. In addition, the crystallinity of cellulose in NLF newsprint samples was significantly lower relative to that of FNP and DNP as shown by 13C NMR spectra. The yield of lignin monomers from TMAH thermochemolysis suggested that hydroxyl groups were removed from the propyl side chain of lignin during the anaerobic decomposition of newsprint in the NLF. Moreover, the vanillyl acid/aldehyde ratio, which successfully describes aerobic lignin degradation, was not a good indicator of the anaerobic degradation of lignin on the basis of the TMAH data. The toluene sorption capacity increased as the degree of newsprint degradation increased or as the O-alkyl/alkyl ratio of newsprint decreased. The results of this study further verified that the sorbent O-alkyl/alkyl ratio is useful for predicting sorption capacities of natural organic materials for hydrophobic organic contaminants.

Subduction beneath Laurentia modified the eastern North American cratonic edge: Evidence from P wave and S wave tomography

NASA Astrophysics Data System (ADS)

Boyce, A.; Bastow, I. D.; Darbyshire, F. A.; Ellwood, A. G.; Gilligan, A.; Levin, V.; Menke, W.

2016-07-01

The cratonic cores of the continents are remarkably stable and long-lived features. Their ability to resist destructive tectonic processes is associated with their thick (˜250 km), cold, chemically depleted, buoyant lithospheric keels that isolate the cratons from the convecting mantle. The formation mechanism and tectonic stability of cratonic keels remains under debate. To address this issue, we use P wave and S wave relative arrival-time tomography to constrain upper mantle structure beneath southeast Canada and the northeast USA, a region spanning three quarters of Earth's geological history. Our models show three distinct, broad zones: Seismic wave speeds increase systematically from the Phanerozoic coastal domains, through the Proterozoic Grenville Province, and to the Archean Superior craton in central Québec. We also recover the NW-SE trending track of the Great Meteor hot spot that crosscuts the major tectonic domains. The decrease in seismic wave speed from Archean to Proterozoic domains across the Grenville Front is consistent with predictions from models of two-stage keel formation, supporting the idea that keel growth may not have been restricted to Archean times. However, while crustal structure studies suggest that Archean Superior material underlies Grenvillian age rocks up to ˜300 km SE of the Grenville Front, our tomographic models show a near-vertical boundary in mantle wave speed directly beneath the Grenville Front. We interpret this as evidence for subduction-driven metasomatic enrichment of the Laurentian cratonic margin, prior to keel stabilization. Variable chemical depletion levels across Archean-Proterozoic boundaries worldwide may thus be better explained by metasomatic enrichment than inherently less depleted Proterozoic composition at formation.

Evaluating Evidence from a Historical Chemical Controversy: A Study in a French High School

ERIC Educational Resources Information Center

Archila, Pablo Antonio

2015-01-01

This paper addresses the importance of evaluating evidence for enriching critical thinking in the chemistry classroom. The purpose of the study was to examine the usefulness of a historical chemical controversy in promoting students' assessment of evidence. The investigation was conducted in a high school in Melun, France. 63 participants (24…

10 CFR 110.32 - Information required in an application for a specific license/NRC Form 7.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) and its chemical and physical form. (2) For enriched uranium, the maximum weight percentage of... and its total dollar value. (4) For nuclear reactors, the name of the facility, its design power level..., physical and chemical characteristics, route of transit of shipment, classification (as defined in § 61.55...

Microbiological Insights of the Cycling of Chloroperoxidase-Reacted Organic Matter

NASA Astrophysics Data System (ADS)

Krzmarzick, M. J.; Boothe, M.; Lim, M. L.; Wang, X.; Brooks, M.

2016-12-01

Chloroperoxidase (CPO) enzymes from fungi are one mechanism in which organic matter is halogenated in terrestrial soils. In microcosm experiments, 17 groups of bacteria were found to substantially become enriched upon CPO-reacted organic matter amendment (CPO-OM). Though some enriched groups were organohalide-respiring bacteria, most were not related to any cultured isolates of bacteria and were either loosely linked to organohalide-degrading cultures or not at all. The large diversity of uncultured bacteria that is enriched from this substrate raises new questions regarding the pathways and mechanisms of the turnover of natural organochlorides. Upon changes in organic matter source material, salinity, temperature, and fermentable substrate, large changes in the CPO-OM enrichment culture occurred due to salinity, temperature, and fermentable substrate, though organic matter source material had a minimal effect. Thus, changes in geophysical conditions, not organic matter (pine forest vs oak forest), dominate the selection of bacteria implicated in the turnover of natural organochlorides. In related experiments, the CPO-OM enrichment culture expresses increased activity towards the dechlorination of chlorinated ethenes, indicating a direct connection between natural organochloride turnover and anthropogenic organochloride degradation and bioremediation, and could partly explain the heterogeneity of natural bioremediation potential at contaminated sites.

Neutron spectrometry for UF 6 enrichment verification in storage cylinders

DOE PAGES

Mengesha, Wondwosen; Kiff, Scott D.

2015-01-29

Verification of declared UF 6 enrichment and mass in storage cylinders is of great interest in nuclear material nonproliferation. Nondestructive assay (NDA) techniques are commonly used for safeguards inspections to ensure accountancy of declared nuclear materials. Common NDA techniques used include gamma-ray spectrometry and both passive and active neutron measurements. In the present study, neutron spectrometry was investigated for verification of UF 6 enrichment in 30B storage cylinders based on an unattended and passive measurement approach. MCNP5 and Geant4 simulated neutron spectra, for selected UF 6 enrichments and filling profiles, were used in the investigation. The simulated neutron spectra weremore » analyzed using principal component analysis (PCA). The PCA technique is a well-established technique and has a wide area of application including feature analysis, outlier detection, and gamma-ray spectral analysis. Results obtained demonstrate that neutron spectrometry supported by spectral feature analysis has potential for assaying UF 6 enrichment in storage cylinders. Thus the results from the present study also showed that difficulties associated with the UF 6 filling profile and observed in other unattended passive neutron measurements can possibly be overcome using the approach presented.« less

Novel meat-enriched foods for older consumers.

PubMed

Farouk, Mustafa M; Yoo, Michelle J Y; Hamid, Nazimah S A; Staincliffe, Maryann; Davies, Briar; Knowles, Scott O

2018-02-01

Red meat enriched versions of bread, spaghetti, yoghurt, ice cream and chocolate were prototyped and assessed for some of their physical, chemical and microbiological properties, as well as sensory appeal. The protein content of the products were significantly increased and their colour went darker with meat enrichment (p<0.05). Bread volume and spaghetti tensile strength increased and ice cream meltability and yoghurt apparent viscosity decreased with meat enrichment (p<0.05). The overall acceptability/liking of bread, flavoured ice cream and spaghetti were not affected (p>0.05) but that of non-flavoured ice cream and yoghurt went down (p<0.05) with meat enrichment. 75% of the 940 panellist who ate the meat-enriched chocolates either loved or slightly-liked them. The outcome of the present study would assist in making the nutrition of meat available in a wider range of product categories, helping the meat industry stretch its established business models, and encouraging further development of novel food choices for elderly and other groups of consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

A cluster-based strategy for assessing the overlap between large chemical libraries and its application to a recent acquisition.

PubMed

Engels, Michael F M; Gibbs, Alan C; Jaeger, Edward P; Verbinnen, Danny; Lobanov, Victor S; Agrafiotis, Dimitris K

2006-01-01

We report on the structural comparison of the corporate collections of Johnson & Johnson Pharmaceutical Research & Development (JNJPRD) and 3-Dimensional Pharmaceuticals (3DP), performed in the context of the recent acquisition of 3DP by JNJPRD. The main objective of the study was to assess the druglikeness of the 3DP library and the extent to which it enriched the chemical diversity of the JNJPRD corporate collection. The two databases, at the time of acquisition, collectively contained more than 1.1 million compounds with a clearly defined structural description. The analysis was based on a clustering approach and aimed at providing an intuitive quantitative estimate and visual representation of this enrichment. A novel hierarchical clustering algorithm called divisive k-means was employed in combination with Kelley's cluster-level selection method to partition the combined data set into clusters, and the diversity contribution of each library was evaluated as a function of the relative occupancy of these clusters. Typical 3DP chemotypes enriching the diversity of the JNJPRD collection were catalogued and visualized using a modified maximum common substructure algorithm. The joint collection of JNJPRD and 3DP compounds was also compared to other databases of known medicinally active or druglike compounds. The potential of the methodology for the analysis of very large chemical databases is discussed.

Highly Selective Enrichment of Glycopeptides Based on Zwitterionically Functionalized Soluble Nanopolymers

NASA Astrophysics Data System (ADS)

Cao, Weiqian; Huang, Jiangming; Jiang, Biyun; Gao, Xing; Yang, Pengyuan

2016-07-01

Efficient glycopeptides enrichment prior to mass spectrometry analysis is essential for glycoproteome study. ZIC-HILIC (zwitterionic hydrophilic interaction liquid chromatography) based glycopeptides enrichment approaches have been attracting more attention for several benefits like easy operating, high enrichment specificity and intact glycopeptide retained. In this study, Poly (amidoamine) dendrimer (PAMAM) was adopted for the synthesis of zwitterionically functionalized (ZICF) materials for glycopeptide enrichment. The multiple branched structure and good solubility of ZICF-PAMAM enables a sufficient interaction with glycopeptides. The ZICF-PAMAM combined with the FASP-mode enrichment strategy exhibits more superior performance compared with the existing methods. It has the minimum detectable concentration of femtomolar level and high recovery rate of over 90.01%, and can efficiently enrich glycopeptides from complex biological samples even for merely 0.1 μL human serum. The remarkable glycopeptides enrichment capacity of ZICF-PAMAM highlights the potential application in in-depth glycoproteome research, which may open up new opportunities for the development of glycoproteomics.

Highly Selective Enrichment of Glycopeptides Based on Zwitterionically Functionalized Soluble Nanopolymers.

PubMed

Cao, Weiqian; Huang, Jiangming; Jiang, Biyun; Gao, Xing; Yang, Pengyuan

2016-07-14

Efficient glycopeptides enrichment prior to mass spectrometry analysis is essential for glycoproteome study. ZIC-HILIC (zwitterionic hydrophilic interaction liquid chromatography) based glycopeptides enrichment approaches have been attracting more attention for several benefits like easy operating, high enrichment specificity and intact glycopeptide retained. In this study, Poly (amidoamine) dendrimer (PAMAM) was adopted for the synthesis of zwitterionically functionalized (ZICF) materials for glycopeptide enrichment. The multiple branched structure and good solubility of ZICF-PAMAM enables a sufficient interaction with glycopeptides. The ZICF-PAMAM combined with the FASP-mode enrichment strategy exhibits more superior performance compared with the existing methods. It has the minimum detectable concentration of femtomolar level and high recovery rate of over 90.01%, and can efficiently enrich glycopeptides from complex biological samples even for merely 0.1 μL human serum. The remarkable glycopeptides enrichment capacity of ZICF-PAMAM highlights the potential application in in-depth glycoproteome research, which may open up new opportunities for the development of glycoproteomics.

Physico-Chemical and Heavy Metal Profiles of Top Soils Sourced from Abandoned Lead-Zinc Mines at Enyigba, Ameri and Ameka Villages, Abakaliki District, Ebonyi State, South Eastern Nigeria

NASA Astrophysics Data System (ADS)

Osayande, D. A.; Azi, E. D.; Obayagbona, N.; Ovwasa, O. M.; Anegbe, B.

2016-12-01

Twenty (20) soil samples were collected from several abandoned old Pb - Zn mines located in Enyigba, Ameri, Ameka villages in the Abakaliki district of Ebonyi State, South-Eastern Nigeria. The soils were analyzed for Fe, Mn, Cu, Zn, Pb, Cd, Ni, Cr, V, pH, organic carbon and Electrical Conductivity using routine procedures. The physic-chemical analyses showed that pH values were generally low. The Electrical conductivity of the soils were high while organic carbon content in the soil was generally low. The heavy metal mean trend indicated that Pb (86) > Zn (64) > Cu (20) > Cd (15) > Ni (7) > Cr (6) > V (1). Fe and Mn values were also high. The variations observed for the heavy metal suggested both geogenic and anthropogenic activities were responsible for their distribution. Soil contamination was assessed on the basis of contamination factor (CF) and enrichment factor (EF). The CF values for the soil revealed moderate contamination for Ni, Cr, V, Zn and Mn, while Pb and Cd showed high contamination. The results of enrichment factor (EF) showed that using Fe concentration in the background value, Ni, Cr, V and Mn had moderate enrichment, Pb and Zn showed significant enrichment while Cd indicated high enrichment. The results of the principal component and cluster analyses showed that Zn, Cu, Cd, Pb metal originated from similar source but may have been significantly influenced by anthropogenic activities, while Ni, Cr, V were attributable to geogenic sources.

Status of stable isotope enrichment, products, and services at the Oak Ridge National Laboratory

NASA Astrophysics Data System (ADS)

Scott Aaron, W.; Tracy, Joe G.; Collins, Emory D.

1997-02-01

The Oak Ridge National Laboratory (ORNL) has been supplying enriched stable and radioactive isotopes to the research, medical, and industrial communities for over 50 y. Very significant changes have occurred in this effort over the past several years, and, while many of these changes have had a negative impact on the availability of enriched isotopes, more recent developments are actually improving the situation for both the users and the producers of enriched isotopes. ORNL is still a major producer and distributor of radioisotopes, but future isotope enrichment operations to be conducted at the Isotope Enrichment Facility (IEF) will be limited to stable isotopes. Among the positive changes in the enriched stable isotope area are a well-functioning, long-term contract program, which offers stability and pricing advantages; the resumption of calutron operations; the adoption of prorated conversion charges, which greatly improves the pricing of isotopes to small users; ISO 9002 registration of the IEF's quality management system; and a much more customer-oriented business philosophy. Efforts are also being made to restore and improve upon the extensive chemical and physical form processing capablities that once existed in the enriched stable isotope program. Innovative ideas are being pursued in both technical and administrative areas to encourage the beneficial use of enriched stable isotopes and the development of related technologies.

The fluidized bed separator

NASA Astrophysics Data System (ADS)

Sharapov, R. R.; Kharlamov, E. V.; Yadykina, V. V.

2018-03-01

In the production of building materials produces a large amount of harmful substances, poisoning atmosphere and adjacent to the building materials site. One of the biggest polluting the ecology of cities adjacent to industry, is metallurgical industry. One of the most important technological processes is the enrichment, in which the rocks are extracted empty components. In the enrichment of iron ore in the production an increasing proportion consist the anthropogenic waste industries, which pollute the air basin and the huge territory around the factories that dumped these same wastes. This reduces as a space for human life and for the functioning and development of cities. These materials can be applied as construction materials, for example, in the preparation of fine-grained concrete as a mineral powder, and these materials can be applied in the construction of roads, housing, for receiving paint etc.

75 FR 52996 - Areva Enrichment Services, LLC (Eagle Rock Enrichment Facility); Notice of Atomic Safety and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-30

... correspondence, documents, and other materials shall continue to be filed in accordance with the NRC E-Filing rule. See 10 CFR 2.302 et seq. Issued at Rockville, Maryland, this 24th day of August 2010. E. Roy...

Complementary IMAC enrichment methods for HLA-associated phosphopeptide identification by mass spectrometry

PubMed Central

Abelin, Jennifer G; Trantham, Paisley D; Penny, Sarah A; Patterson, Andrea M; Ward, Stephen T; Hildebrand, William H; Cobbold, Mark; Bai, Dina L; Shabanowitz, Jeffrey; Hunt, Donald F

2015-01-01

Phosphorylation events within cancer cells often become dysregulated, leading to oncogenic signaling and abnormal cell growth. Phosphopeptides derived from aberrantly phosphorylated proteins that are presented on tumors and not on normal tissues by human leukocyte antigen (HLA) class I molecules are promising candidates for future cancer immunotherapies, because they are tumor specific and have been shown to elicit cytotoxic T cell responses. Robust phosphopeptide enrichments that are suitable for low input amounts must be developed to characterize HLA-associated phosphopeptides from clinical samples that are limited by material availability. We present two complementary mass spectrometry–compatible, iron(III)-immobilized metal affinity chromatography (IMAC) methods that use either nitrilotriacetic acid (NTA) or iminodiacetic acid (IDA) in-house-fabricated columns. We developed these protocols to enrich for subfemtomole-level phosphopeptides from cell line and human tissue samples containing picograms of starting material, which is an order of magnitude less material than what is commonly used. In addition, we added a peptide esterification step to increase phosphopeptide specificity from these low-input samples. To date, hundreds of phosphopeptides displayed on melanoma, ovarian cancer, leukemia and colorectal cancer have been identified using these highly selective phosphopeptide enrichment protocols in combination with a program called ‘CAD Neutral Loss Finder’ that identifies all spectra containing the characteristic neutral loss of phosphoric acid from phosphorylated serine and threonine residues. This methodology enables the identification of HLA-associated phosphopeptides presented by human tissue samples containing as little as nanograms of peptide material in 2 d. PMID:26247297

Improved enrichment culture technique for methane-oxidizing bacteria from marine ecosystems: the effect of adhesion material and gas composition.

PubMed

Vekeman, Bram; Dumolin, Charles; De Vos, Paul; Heylen, Kim

2017-02-01

Cultivation of microbial representatives of specific functional guilds from environmental samples depends largely on the suitability of the applied growth conditions. Especially the cultivation of marine methanotrophs has received little attention, resulting in only a limited number of ex situ cultures available. In this study we investigated the effect of adhesion material and headspace composition on the methane oxidation activity in methanotrophic enrichments obtained from marine sediment. Addition of sterilized natural sediment or alternatively the addition of acid-washed silicon dioxide significantly increased methane oxidation. This positive effect was attributed to bacterial adhesion on the particles via extracellular compounds, with a minimum amount of particles required for effect. As a result, the particles were immobilized, thus creating a stratified environment in which a limited diffusive gas gradients could build up and various microniches were formed. Such diffusive gas gradient might necessitate high headspace concentrations of CH 4 and CO 2 for sufficient concentrations to reach the methane-oxidizing bacteria in the enrichment culture technique. Therefore, high concentrations of methane and carbon dioxide, in addition to the addition of adhesion material, were tested and indeed further stimulated methane oxidation. Use of adhesion material in combination with high concentrations of methane and carbon dioxide might thus facilitate the cultivation and subsequent enrichment of environmentally important members of this functional guild. The exact mechanism of the observed positive effects on methane oxidation and the differential effect on methanotrophic diversity still needs to be explored.

A multi-proxy isotope study (δ41K, δ26Mg, 87Sr/86Sr) of low-temperature oceanic crust alteration: the Troodos Ophiolite and Ocean Drilling Program Hole 801C

NASA Astrophysics Data System (ADS)

Santiago Ramos, D. P.; Higgins, J. A.

2017-12-01

Low-temperature alteration of oceanic crust plays an important role in a number of geochemical cycles, thus modulating the chemical composition of the oceans. In particular, it has been established that low-temperature (<150oC) alteration of basalt is a major sink of seawater potassium. However, little is known about the effects of this process on the potassium isotope composition of seawater, which is 0.5‰ enriched relative to bulk silicate Earth (δ41KBSE=-0.54‰). Here we measure a number of isotope systems (δ41K, δ26Mg, 87Sr/86Sr) in both host rock and vein material from the upper volcanic section of Cretaceous (Troodos Ophiolite) and Jurassic (ODP 801C) oceanic crust using a MC-ICP-MS. The goal is to estimate the K isotopic fractionation associated with basalt alteration in low-temperature conditions, and how it might affect the K isotope enrichment of seawater relative to BSE. We find that marine hydrothermal samples from Troodos and ODP site 801C are enriched in potassium relative to the unaltered glass compositions and have δ41K values both higher and lower than BSE, ranging from -0.45‰ to -0.69‰ (n = 9) and -0.32‰ to -0.71‰ (n = 5), respectively. The low measured δ41K values could represent 1) fractionation (α<1) of K isotopes during uptake from seawater (δ41KSW 0‰), or 2) remobilized mantle-sourced K (δ41KBSE=-0.54‰) from deeper within the ophiolite sequence. Measurements of δ26Mg (n=15) and 87Sr/86Sr (n=12) in these samples yield enriched values relative to bulk silicate Earth, suggesting that alteration of oceanic crust likely happened under high water-to-rock ratios in both Troodos and ODP 801C, and that the added potassium is seawater-sourced. We thus suggest that the isotopically light δ41K values measured in both sites are associated with the formation of secondary clays enriched in the 39K isotope. This light isotope enrichment could be intensified if seawater K sourcing is a diffusion-limited process, as aqueous potassium diffusion has been associated with K isotope fractionations between 0.9967 and 0.9984. Our results indicate that the uptake of potassium in altered oceanic crust could be responsible, in part, for the observed K isotope enrichment of seawater relative to bulk silicate Earth.

Effect of red clay on diesel bioremediation and soil bacterial community.

PubMed

Jung, Jaejoon; Choi, Sungjong; Hong, Hyerim; Sung, Jung-Suk; Park, Woojun

2014-08-01

Red clay is a type of soil, the red color of which results from the presence of iron oxide. It is considered an eco-friendly material, with many industrial, cosmetic, and architectural uses. A patented method was applied to red clay in order to change its chemical composition and mineral bioavailability. The resulting product was designated processed red clay. This study evaluates the novel use of red clay and processed red clay as biostimulation agents in diesel-contaminated soils. Diesel biodegradation was enhanced in the presence of red clay and processed red clay by 4.9- and 6.7-fold, respectively, and the number of culturable bacterial cells was correlated with the amount of diesel biodegradation. The growth of Acinetobacter oleivorans DR1, Pseudomonas putida KT2440, and Cupriavidus necator was promoted by both types of red clays. Culture-independent community analysis determined via barcoded pyrosequencing indicated that Nocardioidaceae, Xanthomonadaceae, Pseudomonadaceae, and Caulobacteraceae were enriched by diesel contamination. Bacterial strain isolation from naphthalene- and liquid paraffin-amended media was affiliated with enriched taxa based on 16S rRNA gene sequence identity. We suggest that the biostimulating mechanism of red clay and processed red clay is able to support bacterial growth without apparent selection for specific bacterial species.

61Ni synchrotron radiation-based Mössbauer spectroscopy of nickel-based nanoparticles with hexagonal structure

PubMed Central

Masuda, Ryo; Kobayashi, Yasuhiro; Kitao, Shinji; Kurokuzu, Masayuki; Saito, Makina; Yoda, Yoshitaka; Mitsui, Takaya; Hosoi, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi; Seto, Makoto

2016-01-01

We measured the synchrotron-radiation (SR)-based Mössbauer spectra of Ni-based nanoparticles with a hexagonal structure that were synthesised by chemical reduction. To obtain Mössbauer spectra of the nanoparticles without 61Ni enrichment, we developed a measurement system for 61Ni SR-based Mössbauer absorption spectroscopy without X-ray windows between the 61Ni84V16 standard energy alloy and detector. The counting rate of the 61Ni nuclear resonant scattering in the system was enhanced by the detection of internal conversion electrons and the close proximity between the energy standard and the detector. The spectrum measured at 4 K revealed the internal magnetic field of the nanoparticles was 3.4 ± 0.9 T, corresponding to a Ni atomic magnetic moment of 0.3 Bohr magneton. This differs from the value of Ni3C and the theoretically predicted value of hexagonal-close-packed (hcp)-Ni and suggested the nanoparticle possessed intermediate carbon content between hcp-Ni and Ni3C of approximately 10 atomic % of Ni. The improved 61Ni Mössbauer absorption measurement system is also applicable to various Ni materials without 61Ni enrichment, such as Ni hydride nanoparticles. PMID:26883185

Geochemistry of loess-paleosol sediments of Kashmir Valley, India: Provenance and weathering

NASA Astrophysics Data System (ADS)

Ahmad, Ishtiaq; Chandra, Rakesh

2013-04-01

Middle to Late Pleistocene loess-paleosol sediments of Kashmir Valley, India, were analyzed for major, trace and REE elements in order to determine their chemical composition, provenance and intensity of palaeo-weathering of the source rocks. These sediments are generally enriched with Fe2O3, MgO, MnO, TiO2, Y, Ni, Cu, Zn, Th, U, Sc, V and Co while contents of SiO2, K2O, Na2O, P2O5, Sr, Nb and Hf are lower than the UCC. Chondrite normalized REE patterns are characterized by moderate enrichment of LREEs, relatively flat HREE pattern (GdCN/YbCN = 1.93-2.31) and lack of prominent negative Eu anomaly (Eu/Eu* = 0.73-1.01, average = 0.81). PAAS normalized REE are characterized by slightly higher LREE, depleted HREE and positive Eu anomaly. Various provenance discrimination diagrams reveal that the Kashmir Loess-Paleosol sediments are derived from the mixed source rocks suggesting large provenance with variable geological settings, which apparently have undergone weak to moderate recycling processes. Weathering indices such as CIA, CIW and PIA values (71.87, 83.83 and 80.57 respectively) and A-CN-K diagram imply weak to moderate weathering of the source material.

Anti-tumor and anti-angiogenic ergosterols from Ganoderma lucidum

NASA Astrophysics Data System (ADS)

Chen, Shaodan; Yong, Tianqiao; Zhang, Yifang; Su, Jiyan; Jiao, Chunwei; Xie, Yizhen

2017-10-01

This study was carried out to isolate chemical constituents from the lipid enriched fraction of Ganoderma lucidum extract and to evaluate their anti-proliferative effect on cancer cell lines and human umbilical vein endothelial cells. Ergosterol derivatives (1-14) were isolated from the lipid enriched fraction of G. lucidum. Their structures were established on the basis of spectroscopic analyses or by comparison of mass and NMR spectral data with those reported previously. Amongst, compound 1 was isolated and identified as a new compound. All the compounds were evaluated for their inhibitory effect on tumor cells and human umbilical vein endothelial cells in vitro. Compounds 9-13 displayed inhibitory activity against two tumor cell lines and human umbilical vein endothelial cells, which indicated that these four compounds had both anti-tumor and anti-angiogenesis activities. Compound 2 had significant selective inhibition against two tumor cell lines, while 3 exhibited selective inhibition against human umbilical vein endothelial cells. The structure–activity relationships for inhibiting human HepG2 cells were revealed by 3D-QASR. Ergosterol content in different parts of the raw material and products of G. lucidum was quantified. This study provides a basis for further development and utilization of ergosterol derivatives as natural nutraceuticals and functional food ingredients, or as source of new potential antitumor or anti-angiogenesis chemotherapy agent.

Magnesium enriched lactic acid bacteria as a carrier for probiotic ice cream production.

PubMed

Góral, Małgorzata; Kozłowicz, Katarzyna; Pankiewicz, Urszula; Góral, Dariusz

2018-01-15

The following strains of bacteria: Lactobacillus rhamnosus B 442, Lactobacillus rhamnosus 1937, and Lactococcus lactis JBB 500 were enriched with magnesium ions using Pulsed Electric Fields. The potentially probiotic strains were added to the mixture in the DVS process and applied for the production of ice cream which were then analyzed physicochemically and microbiologically. Results showed that addition of bacteria enriched with magnesium did not change chemical parameters of the ice cream and did not affect the freezing process, meltability, and hardness. No significant differences were noted in colour of the samples. The ice cream with addition of bacteria enriched with magnesium had higher adhesiveness. The results of viability determination showed that the total number of microorganisms in the ice cream was higher than in the starter cultures. Viability of the bacteria enriched with magnesium in the obtained ice cream was lower in comparison to the control samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transcriptomic effects-based monitoring for endocrine active chemicals: Assessing relative contribution of treated wastewater to downstream pollution

USGS Publications Warehouse

Martinovic-Weigelt, Dalma; Mehinto, Alvine C.; Ankley, Gerald T.; Denslow, Nancy D.; Barber, Larry B.; Lee, Kathy E.; King, Ryan J.; Schoenfuss, Heiko L.; Schroeder, Anthony L.; Villeneuve, Daniel L.

2014-01-01

The present study investigated whether a combination of targeted analytical chemistry information with unsupervised, data-rich biological methodology (i.e., transcriptomics) could be utilized to evaluate relative contributions of wastewater treatment plant (WWTP) effluents to biological effects. The effects of WWTP effluents on fish exposed to ambient, receiving waters were studied at three locations with distinct WWTP and watershed characteristics. At each location, 4 d exposures of male fathead minnows to the WWTP effluent and upstream and downstream ambient waters were conducted. Transcriptomic analyses were performed on livers using 15 000 feature microarrays, followed by a canonical pathway and gene set enrichment analyses. Enrichment of gene sets indicative of teleost brain–pituitary–gonadal–hepatic (BPGH) axis function indicated that WWTPs serve as an important source of endocrine active chemicals (EACs) that affect the BPGH axis (e.g., cholesterol and steroid metabolism were altered). The results indicated that transcriptomics may even pinpoint pertinent adverse outcomes (i.e., liver vacuolization) and groups of chemicals that preselected chemical analytes may miss. Transcriptomic Effects-Based monitoring was capable of distinguishing sites, and it reflected chemical pollution gradients, thus holding promise for assessment of relative contributions of point sources to pollution and the efficacy of pollution remediation.

Use of RecA protein to enrich for homologous genes in a genomic library

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taidi-Laskowski, B.; Grumet, F.C.; Tyan, D.

1988-08-25

RecA protein-coated probe has been utilized to enrich genomic digests for desired genes in order to facilitate cloning from genomic libraries. Using a previously cloned HLA-B27 gene as the recA-coated enrichment probe, the authors obtained a mean 108x increase in the ratio of specific to nonspecific plaques in lambda libraries screened for B27 variant alleles of estimated 99% homology to the probe. Class I genes of lesser homology were less enriched. Loss of genomic DNA during the enrichment procedure can, however, restrict application of this technique whenever starting genomic DNA is very limited. Nevertheless, the impressive reduction in cloning effortmore » and material makes recA enrichment a useful new tool for cloning homologous genes from genomic DNA.« less

The U.S. national nuclear forensics library, nuclear materials information program, and data dictionary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lamont, Stephen Philip; Brisson, Marcia; Curry, Michael

2011-02-17

Nuclear forensics assessments to determine material process history requires careful comparison of sample data to both measured and modeled nuclear material characteristics. Developing centralized databases, or nuclear forensics libraries, to house this information is an important step to ensure all relevant data will be available for comparison during a nuclear forensics analysis and help expedite the assessment of material history. The approach most widely accepted by the international community at this time is the implementation of National Nuclear Forensics libraries, which would be developed and maintained by individual nations. This is an attractive alternative toan international database since it providesmore » an understanding that each country has data on materials produced and stored within their borders, but eliminates the need to reveal any proprietary or sensitive information to other nations. To support the concept of National Nuclear Forensics libraries, the United States Department of Energy has developed a model library, based on a data dictionary, or set of parameters designed to capture all nuclear forensic relevant information about a nuclear material. Specifically, information includes material identification, collection background and current location, analytical laboratories where measurements were made, material packaging and container descriptions, physical characteristics including mass and dimensions, chemical and isotopic characteristics, particle morphology or metallurgical properties, process history including facilities, and measurement quality assurance information. While not necessarily required, it may also be valuable to store modeled data sets including reactor burn-up or enrichment cascade data for comparison. It is fully expected that only a subset of this information is available or relevant to many materials, and much of the data populating a National Nuclear Forensics library would be process analytical or material accountability measurement data as opposed to a complete forensic analysis of each material in the library.« less

10 CFR 70.60 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Certain Licensees Authorized To Possess a Critical Mass of Special Nuclear Material § 70.60 Applicability... critical mass of special nuclear material, and engaged in enriched uranium processing, fabrication of...

The NASA/JPL Evaluation of Oxygen Interactions with Materials-3 (EOIM-3)

NASA Technical Reports Server (NTRS)

Brinza, David E.; Chung, Shirley Y.; Minton, Timothy K.; Liang, Ranty H.

1994-01-01

The deleterious effects of hyperthermal atomic oxygen (AO) found in low-earth-orbit (LEO) environments on critical flight materials has been known since early shuttle flights. This corrosive effect is of considerable concern because it compromises the performance and longevity of spacecraft/satellite materials deployed for extended periods in LEO. The NASA Evaluation of Oxygen Interactions with Materials-3 (EOIM-3) experiment served as a testbed for a variety of candidate flight materials for space assets. A total of 57 JPL test specimens were present in six subexperiments aboard EOIM-3. In addition to a number of passive exposure materials for flight and advanced technology programs, several subexperiments were included to provide data for understanding the details of atomic oxygen interactions with materials. Data and interpretations are presented for the heated tray, heated strips, solar ultraviolet exposure, and scatterometer subexperiments, along with a detailed description of the exposure conditions experienced by materials in the various experiments. Mass spectra of products emerging from identical samples of a (sup 13)C-enriched polyimide polymer (chemically equivalent to Kapton) under atomic oxygen bombardment in space and in the laboratory were collected. Reaction products unambiguously detected in space were (sup 13)CO, NO, (sup 12)CO2, and (sup 13)CO2. These reaction products and two others, H2O and (sup 12)CO, were detected in the laboratory, along with inelastically scattered atomic and molecular oxygen. Qualitative agreement was seen in the mass spectra taken in space and in the laboratory; the agreement may be improved by reducing the fraction of O2 in the laboratory molecular beam.

Development of Optical Crystals for High Power and Tunable Visible and Infrared Light Generation

DTIC Science & Technology

2015-02-11

ultra high chemical purity (5N), 95% isotopically enriched 6Li was purified in a multi-stage vacuum distillation process previously reported by...enriched 6Li was purified in a multi-stage vacuum distillation process previously reported by Stowe et al.[4]. 6LiIn alloy was synthesized in a... quantum mechanics, it has been determined that atoms, molecules, ions have discrete energy levels. Therefore there exists allowed atomic transitions

Spectral pathways for exploration of secondary uranium: An investigation in the desertic tracts of Rajasthan and Gujarat, India

NASA Astrophysics Data System (ADS)

Bharti, Rishikesh; Kalimuthu, R.; Ramakrishnan, D.

2015-10-01

This study aims at identifying potential zones of secondary uranium enrichment using hyperspectral remote sensing, γ-ray spectrometry, fluorimetry and geochemical techniques in the western Rajasthan and northern Gujarat, India. The investigated area has suitable source rocks, conducive past-, and present-climate that can facilitate such enrichment. This enrichment process involves extensive weathering of uranium bearing source rocks, leaching of uranyl compounds in groundwater, and their precipitation in chemical deltas along with duricrusts like calcretes and gypcretes. Spatial distribution of groundwater calcretes (that are rich in Mg-calcite) and gypcretes (that are rich in gypsum) along palaeochannels and chemical deltas were mapped using hyperspectral remote sensing data based on spectral absorptions in 1.70 μm, 2.16 μm, 2.21 μm, 2.33 μm, 2.44 μm wavelength regions. Subsequently based on field radiometric survey, zones of U anomalies were identified and samples of duricrusts and groundwater were collected for geochemical analyses. Anomalous concentration of U (2345.7 Bq/kg) and Th (142.3 Bq/kg) are observed in both duricrusts and groundwater (U-1791 μg/l, Th-34 μg/l) within the palaeo-delta and river confluence. The estimated carnotite Solubility Index also indicates the secondary enrichment of U and the likelihood of occurrence of an unconventional deposit.

Europa's Crust and Ocean: Origin, Composition, and the Prospects for Life

USGS Publications Warehouse

Kargel, J.S.; Kaye, J.Z.; Head, J. W.; Marion, G.M.; Sassen, R.; Crowley, J.K.; Ballesteros, O.P.; Grant, S.A.; Hogenboom, D.L.

2000-01-01

We have considered a wide array of scenarios for Europa's chemical evolution in an attempt to explain the presence of ice and hydrated materials on its surface and to understand the physical and chemical nature of any ocean that may lie below. We postulate that, following formation of the jovian system, the europan evolutionary sequence has as its major links: (a) initial carbonaceous chondrite rock, (b) global primordial aqueous differentiation and formation of an impure primordial hydrous crust, (c) brine evolution and intracrustal differentiation, (d) degassing of Europa's mantle and gas venting, (e) hydrothermal processes, and (f) chemical surface alteration. Our models were developed in the context of constraints provided by Galileo imaging, near infrared reflectance spectroscopy, and gravity and magnetometer data. Low-temperature aqueous differentiation from a carbonaceous CI or CM chondrite precursor, without further chemical processing, would result in a crust/ocean enriched in magnesium sulfate and sodium sulfate, consistent with Galileo spectroscopy. Within the bounds of this simple model, a wide range of possible layered structures may result; the final state depends on the details of intracrustal differentiation. Devolatilization of the rocky mantle and hydrothermal brine reactions could have produced very different ocean/crust compositions, e.g., an ocean/crust of sodium carbonate or sulfuric acid, or a crust containing abundant clathrate hydrates. Realistic chemical-physical evolution scenarios differ greatly in detailed predictions, but they generally call for a highly impure and chemically layered crust. Some of these models could lead also to lateral chemical heterogeneities by diapiric upwellings and/or cryovolcanism. We describe some plausible geological consequences of the physical-chemical structures predicted from these scenarios. These predicted consequences and observed aspects of Europa's geology may serve as a basis for further analys is and discrimination among several alternative scenarios. Most chemical pathways could support viable ecosystems based on analogy with the metabolic and physiological versatility of terrestrial microorganisms. ?? 2000 Academic Press.

49 CFR 173.417 - Authorized fissile materials packages.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for export and import shipments. (2) A residual “heel” of enriched solid uranium hexafluoride may be... “Heel” in a Specification 7A Cylinder) Maximum cylinder diameter Centimeters Inches Cylinder volume Liters Cubic feet Maximum Uranium 235-enrichment (weight)percent Maximum “Heel” weight per cylinder UF6...

49 CFR 173.417 - Authorized fissile materials packages.

Code of Federal Regulations, 2011 CFR

2011-10-01

... for export and import shipments. (2) A residual “heel” of enriched solid uranium hexafluoride may be... “Heel” in a Specification 7A Cylinder) Maximum cylinder diameter Centimeters Inches Cylinder volume Liters Cubic feet Maximum Uranium 235-enrichment (weight)percent Maximum “Heel” weight per cylinder UF6...

78 FR 75579 - Low Enriched Uranium From France

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-12

... From France Determination On the basis of the record \\1\\ developed in the subject five-year review, the... uranium from France would be likely to lead to continuation or recurrence of material injury to an... Commission are contained in USITC Publication 4436 (December 2013), entitled Low Enriched Uranium from France...

75 FR 12581 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-16

...; Commencement of Construction Requirements; AREVA Enrichment Services, Eagle Rock Enrichment Facility..., Division of Fuel Cycle Safety and Safeguards, Office of Nuclear Material Safety and Safeguards, U.S... the site. Site grading and erosion control. Excavating the site including rock blasting and removal...

Better vacuum by removal of diffusion-pump-oil contaminants

NASA Technical Reports Server (NTRS)

Buggele, A. E.

1975-01-01

The complex problem of why large space simulation chambers do not realize true ultimate vacuum was investigated. Some contaminating factors affecting diffusion pump performance were identified, and some advances in vacuum distillation-fractionation technology were achieved which resulted in a two-decade-or-more lower ultimate pressure. Data are presented to show the overall or individual contaminating effects of commonly used phthalate ester plasticizers of 390 to 530 molecular weight on diffusion pump performance. Methods for removing contaminants from diffusion pump silicone oil during operation and for reclaiming contaminated oil by high-vacuum molecular distillation are described. Conceptual self-cleansing designs and operating procedures are proposed for modifying large diffusion pumps into high-efficiency distillation devices. The potential exists for application of these technological advancements to other disciplines, such as medicine, biomedical materials, metallurgy, refining, and chemical (diffusion-enrichment) processing.

Dust episodes in Beirut and their effect on the chemical composition of coarse and fine particulate matter.

PubMed

Jaafar, Malek; Baalbaki, Rima; Mrad, Raya; Daher, Nancy; Shihadeh, Alan; Sioutas, Constantinos; Saliba, Najat A

2014-10-15

Particles captured during dust episodes in Beirut originated from both the African and Arabian deserts. This particular air mixture showed an increase, over non-dust episodes, in particle volume distribution which was mostly noticed for particles ranging in sizes between 2.25 and 5 μm. It also resulted in an increase in average mass concentration by 48.5% and 14.6%, for the coarse and fine fractions, respectively. Chemical analysis of major aerosol components accounted for 93% of fine PM and 71% of coarse PM. Crustal material (CM) dominated the coarse PM fraction, contributing to 39 ± 15% of the total mass. Sea salt (SS) (11 ± 10%) and secondary ions (SI) (11 ± 7%) were the second most abundant elements. In the fine fraction, SI (36 ± 14%) were the most abundant PM constituent, followed by organic matter (OM) (33 ± 7%) and CM (13 ± 2%). Enrichment factors (EF) and correlation coefficients show that biogenic and anthropogenic sources contribute to the elemental composition of particles during dust episodes. This study emphasizes on the role played by the long-range transport of aerosols in changing the chemical composition of the organic and inorganic constituents of urban coarse and fine PM. The chemical reactions between aged urban and dust aerosols are enhanced during transport, leading to the formation of organo-nitrogenated and -sulfonated compounds. Their oligomeric morphologies are further confirmed by SEM-EDX measurements. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of interfacial interaction on the properties of poly(vinyl chloride)/styrene-butadiene rubber blends

NASA Astrophysics Data System (ADS)

Zhu, Shuihan

PVC/SBR blends---new thermoplastic elastomer material---were developed. They have potential applications due to low costs and low-temperature elasticity. A unique compatibilization method was employed to enhance the mechanical properties of the materials a compatibilizer miscible with one of the blend components can react chemically with the other component(s). Improvements in tensile and impact behavior were observed as a result of the compatibilization. A novel characterization technique to study the interface of PVC/SBR blends was developed. This technique involves the observation of the unstained sample under electron beam irradiation by a transmission electron microscope (TEM). An enrichment of rubber at the interface between PVC and SBR was detected in the compatiblized PVC/SBR blends. Magnetic relaxation measurements show that the rubber concentration in the proximity of PVC increases with the degree of covulcanization between NBR and SBR. The interface development and the rheological effect during processing were investigated. The interfacial concentration profile and the interfacial thickness were obtained by grayscale measurements on TEM micrographs, evaluation of SIMS images, and measurements of micromechanical properties.

Graphene/graphene oxide and their derivatives in the separation/isolation and preconcentration of protein species: A review.

PubMed

Chen, Xuwei; Hai, Xin; Wang, Jianhua

2016-05-30

The distinctive/unique electrical, chemical and optical properties make graphene/graphene oxide-based materials popular in the field of analytical chemistry. Its large surface offers excellent capacity to anchor target analyte, making it an powerful sorbent in the adsorption and preconcentration of trace level analyte of interest in the field of sample preparation. The large delocalized π-electron system of graphene framework provides strong affinity to species containing aromatic rings, such as proteins, and the abundant active sites on its surface offers the chance to modulate adsorption tendency towards specific protein via functional modification/decoration. This review provides an overview of the current research on graphene/graphene oxide-based materials as attractive and powerful adsorption media in the separation/isolation and preconcentration of protein species from biological sample matrixes. These practices are aiming at providing protein sample of high purity for further investigations and applications, or to achieve certain extent of enrichment prior to quantitative assay. In addition, the challenges and future perspectives in the related research fields have been discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Isotopic compositions of cometary matter returned by Stardust.

PubMed

McKeegan, Kevin D; Aléon, Jerome; Bradley, John; Brownlee, Donald; Busemann, Henner; Butterworth, Anna; Chaussidon, Marc; Fallon, Stewart; Floss, Christine; Gilmour, Jamie; Gounelle, Matthieu; Graham, Giles; Guan, Yunbin; Heck, Philipp R; Hoppe, Peter; Hutcheon, Ian D; Huth, Joachim; Ishii, Hope; Ito, Motoo; Jacobsen, Stein B; Kearsley, Anton; Leshin, Laurie A; Liu, Ming-Chang; Lyon, Ian; Marhas, Kuljeet; Marty, Bernard; Matrajt, Graciela; Meibom, Anders; Messenger, Scott; Mostefaoui, Smail; Mukhopadhyay, Sujoy; Nakamura-Messenger, Keiko; Nittler, Larry; Palma, Russ; Pepin, Robert O; Papanastassiou, Dimitri A; Robert, François; Schlutter, Dennis; Snead, Christopher J; Stadermann, Frank J; Stroud, Rhonda; Tsou, Peter; Westphal, Andrew; Young, Edward D; Ziegler, Karen; Zimmermann, Laurent; Zinner, Ernst

2006-12-15

Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single (17)O-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is (16)O-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion.

CHEERS: Chemical enrichment of clusters of galaxies measured using a large XMM-Newton sample

NASA Astrophysics Data System (ADS)

de Plaa, J.; Mernier, F.; Kaastra, J.; Pinto, C.

2017-10-01

The Chemical Enrichment RGS Sample (CHEERS) is aimed to be a sample of the most optimal clusters of galaxies for observation with the Reflection Grating Spectrometer (RGS) aboard XMM-Newton. It consists of 5 Ms of deep cluster observations of 44 objects obtained through a very large program and archival observations. The main goal is to measure chemical abundances in the hot Intra-Cluster Medium (ICM) of clusters to provide constraints on chemical evolution models. Especially the origin and evolution of type Ia supernovae is still poorly known and X-ray observations could contribute to constrain models regarding the SNIa explosion mechanism. Due to the high quality of the data, the uncertainties on the abundances are dominated by systematic effects. By carefully treating each systematic effect, we increase the accuracy or estimate the remaining uncertainty on the measurement. The resulting abundances are then compared to supernova models. In addition, also radial abundance profiles are derived. In the talk, we present an overview of the results that the CHEERS collaboration obtained based on the CHEERS data. We focus on the abundance measurements. The other topics range from turbulence measurements through line broadening to cool gas in groups.

Comparison between electrocoagulation and chemical precipitation for metals removal from acidic soil leachate.

PubMed

Meunier, Nathalie; Drogui, Patrick; Montané, Camille; Hausler, Robert; Mercier, Guy; Blais, Jean-François

2006-09-01

This paper provides a quantitative comparison between electrocoagulation and chemical precipitation based on heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) removal from acidic soil leachate (ASL) at the laboratory pilot scale. Chemical precipitation was evaluated using either calcium hydroxide or sodium hydroxide, whereas electrocoagulation was evaluated via an electrolytic cell using mild steel electrodes. Chemical precipitation was as effective as electrocoagulation in removing metals from ASL having low contamination levels (30 mg Pbl(-1) and 18 mg Znl(-1)). For ASL enriched with different metals (each concentration of metals was initially adjusted to 100 mg l(-1)), the residual Cr, Cu, Pb and Zn concentrations at the end of the experiments were below the acceptable level recommended for discharge in sewage urban works (more than 99.8% of metal was removed) using either electrocoagulation or chemical precipitation. Cd was more effectively removed by electrochemical treatment, whereas Ni was easily removed by chemical treatment. The cost for energy, chemicals and disposal of metallic residue of electrocoagulation process ranged from USD 8.83 to 13.95 tds(-1), which was up to five times lower than that recorded using chemical precipitation. Highly effective electrocoagulation was observed as the ASL was specifically enriched with high concentration of Pb (250-2000 mg Pbl(-1)). More than 99.5% of Pb was removed regardless of the initial Pb concentration imposed in ASL and, in all cases, the residual Pb concentrations (0.0-1.44 mg l(-1)) were below the limiting value (2.0 mg l(-1)) for effluent discharge in sewage works.

Inorganic trace analysis by mass spectrometry

NASA Astrophysics Data System (ADS)

Becker, Johanna Sabine; Dietze, Hans-Joachim

1998-10-01

Mass spectrometric methods for the trace analysis of inorganic materials with their ability to provide a very sensitive multielemental analysis have been established for the determination of trace and ultratrace elements in high-purity materials (metals, semiconductors and insulators), in different technical samples (e.g. alloys, pure chemicals, ceramics, thin films, ion-implanted semiconductors), in environmental samples (waters, soils, biological and medical materials) and geological samples. Whereas such techniques as spark source mass spectrometry (SSMS), laser ionization mass spectrometry (LIMS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), glow discharge mass spectrometry (GDMS), secondary ion mass spectrometry (SIMS) and inductively coupled plasma mass spectrometry (ICP-MS) have multielemental capability, other methods such as thermal ionization mass spectrometry (TIMS), accelerator mass spectrometry (AMS) and resonance ionization mass spectrometry (RIMS) have been used for sensitive mono- or oligoelemental ultratrace analysis (and precise determination of isotopic ratios) in solid samples. The limits of detection for chemical elements using these mass spectrometric techniques are in the low ng g -1 concentration range. The quantification of the analytical results of mass spectrometric methods is sometimes difficult due to a lack of matrix-fitted multielement standard reference materials (SRMs) for many solid samples. Therefore, owing to the simple quantification procedure of the aqueous solution, inductively coupled plasma mass spectrometry (ICP-MS) is being increasingly used for the characterization of solid samples after sample dissolution. ICP-MS is often combined with special sample introduction equipment (e.g. flow injection, hydride generation, high performance liquid chromatography (HPLC) or electrothermal vaporization) or an off-line matrix separation and enrichment of trace impurities (especially for characterization of high-purity materials and environmental samples) is used in order to improve the detection limits of trace elements. Furthermore, the determination of chemical elements in the trace and ultratrace concentration range is often difficult and can be disturbed through mass interferences of analyte ions by molecular ions at the same nominal mass. By applying double-focusing sector field mass spectrometry at the required mass resolution—by the mass spectrometric separation of molecular ions from the analyte ions—it is often possible to overcome these interference problems. Commercial instrumental equipment, the capability (detection limits, accuracy, precision) and the analytical application fields of mass spectrometric methods for the determination of trace and ultratrace elements and for surface analysis are discussed.

[Study on action mechanism and material base of compound Danshen dripping pills in treatment of carotid atherosclerosis based on techniques of gene expression profile and molecular fingerprint].

PubMed

Zhou, Wei; Song, Xiang-gang; Chen, Chao; Wang, Shu-mei; Liang, Sheng-wang

2015-08-01

Action mechanism and material base of compound Danshen dripping pills in treatment of carotid atherosclerosis were discussed based on gene expression profile and molecular fingerprint in this paper. First, gene expression profiles of atherosclerotic carotid artery tissues and histologically normal tissues in human body were collected, and were screened using significance analysis of microarray (SAM) to screen out differential gene expressions; then differential genes were analyzed by Gene Ontology (GO) analysis and KEGG pathway analysis; to avoid some genes with non-outstanding differential expression but biologically importance, Gene Set Enrichment Analysis (GSEA) were performed, and 7 chemical ingredients with higher negative enrichment score were obtained by Cmap method, implying that they could reversely regulate the gene expression profiles of pathological tissues; and last, based on the hypotheses that similar structures have similar activities, 336 ingredients of compound Danshen dripping pills were compared with 7 drug molecules in 2D molecular fingerprints method. The results showed that 147 differential genes including 60 up-regulated genes and 87 down regulated genes were screened out by SAM. And in GO analysis, Biological Process ( BP) is mainly concerned with biological adhesion, response to wounding and inflammatory response; Cellular Component (CC) is mainly concerned with extracellular region, extracellular space and plasma membrane; while Molecular Function (MF) is mainly concerned with antigen binding, metalloendopeptidase activity and peptide binding. KEGG pathway analysis is mainly concerned with JAK-STAT, RIG-I like receptor and PPAR signaling pathway. There were 10 compounds, such as hexadecane, with Tanimoto coefficients greater than 0.85, which implied that they may be the active ingredients (AIs) of compound Danshen dripping pills in treatment of carotid atherosclerosis (CAs). The present method can be applied to the research on material base and molecular action mechanism of TCM.

Fluxes to sediments underlying the Rainbow hydrothermal plume at 36°14‧N on the Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Cave, R. R.; German, C. R.; Thomson, J.; Nesbitt, R. W.

2002-06-01

A geochemical investigation has been conducted of a suite of four sediment cores collected from directly beneath the hydrothermal plume at distances of 2 to 25 km from the Rainbow hydrothermal field. As well as a large biogenic component (>80% CaCO3) these sediments record clear enrichments of the elements Fe, Cu, Mn, V, P, and As from hydrothermal plume fallout but only minor detrital background material. Systematic variations in the abundances of ;hydrothermal; elements are observed at increasing distance from the vent site, consistent with chemical evolution of the dispersing plume. Further, pronounced Ni and Cr enrichments at specific levels within each of the two cores collected from closest to the vent site are indicative of discrete episodes of additional input of ultrabasic material at these two near-field locations. Radiocarbon dating reveals mean Holocene accumulation rates for all four cores of 2.7 to 3.7 cm.kyr-1, with surface mixed layers 7 to 10+ cm thick, from which a history of deposition from the Rainbow hydrothermal plume can be deduced. Deposition from the plume supplies elements to the underlying sediments that are either directly hydrothermally sourced (e.g., Fe, Mn, Cu) or scavenged from seawater via the hydrothermal plume (e.g., V, P, As). Holocene fluxes into to the cores' surface mixed layers are presented which, typically, are an order of magnitude greater than ;background; authigenic fluxes from the open North Atlantic. One core, collected closest to the vent site, indicates that both the concentration and flux of hydrothermally derived material increased significantly at some point between 8 and 12 14C kyr ago; the preferred explanation is that this variation reflects the initiation/intensification of hydrothermal venting at the Rainbow hydrothermal field at this time-perhaps linked to some specific tectonic event in this fault-controlled hydrothermal setting.

Planetary Differentiation by Aerial Metasomatism

NASA Astrophysics Data System (ADS)

Baker, D. R.

2018-05-01

Dissolution of surficial rocks will occur on planetary bodies with steam atmospheres. Although the amount of dissolved material is small, metasomatism of chondritic compositions produces siliceous crustal materials and enriches residual rocks.

Method for distributing chemicals through a fibrous material using low-headspace dielectric heating

DOEpatents

Banerjee, Sujit; Malcolm, Earl

2002-01-01

System and method for diffusing chemicals rapidly and evenly into and through fibrous material, such as wood. Chemicals are introduced into the fibrous material by applying the chemicals to the fibrous material. After treating the fibrous material with the chemicals, the fibrous material is maintained under low-headspace conditions. Thermal energy or dielectric heating, such as microwave or radio frequency energy, is applied to the fibrous material. As a result, the chemicals are able to distribute evenly and quickly throughout the fibrous material.

Producing and quantifying enriched para-H2.

PubMed

Tom, Brian A; Bhasker, Siddhartha; Miyamoto, Yuki; Momose, Takamasa; McCall, Benjamin J

2009-01-01

The production of enriched para-H(2) is useful for many scientific applications, but the technology for producing and measuring para-H(2) is not yet widespread. In this note and in the accompanying auxiliary material, we describe the design, construction, and use of a versatile standalone converter that is capable of producing para-H(2) enrichments of up to > or = 99.99% at continuous flow rates of up to 0.4 SLM. We also discuss para-H(2) storage and back conversion rates, and improvements to three techniques (thermal conductance, NMR, and solid hydrogen impurity spectroscopy) used to quantify the para-H(2) enrichment.

Uranium Conversion & Enrichment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karpius, Peter Joseph

2017-02-06

The isotopes of uranium that are found in nature, and hence in ‘fresh’ Yellowcake’, are not in relative proportions that are suitable for power or weapons applications. The goal of conversion then is to transform the U 3O 8 yellowcake into UF 6. Conversion and enrichment of uranium is usually required to obtain material with enough 235U to be usable as fuel in a reactor or weapon. The cost, size, and complexity of practical conversion and enrichment facilities aid in nonproliferation by design.

Water quality assessment using the AREc32 reporter gene assay indicative of the oxidative stress response pathway.

PubMed

Escher, Beate I; Dutt, Mriga; Maylin, Erin; Tang, Janet Y M; Toze, Simon; Wolf, C Roland; Lang, Matti

2012-11-01

The reporter gene assay AREc32 is based on the induction of the Nrf2 mediated oxidative stress response pathway in the human breast cancer cell line MCF7, where eight copies of the antioxidant response element (ARE) are linked to a reporter gene encoding for luciferase. The Nrf2-ARE pathway is responsive to many chemicals that cause oxidative stress, among them a large number of pesticides and skin irritants. We adopted and validated the AREc32 bioassay for water quality testing. tert-Butylhydroquinone served as the positive control, phenol as the negative control and other reactive chemicals were assessed for their specificity. An environmentally relevant reference chemical, benzo(a)pyrene was the most potent inducer of all tested chemicals. The concentration causing an induction ratio (IR) of 1.5 (EC(IR1.5)) was chosen as the effect benchmark value. The assay was applied to 21 water samples ranging from sewage to drinking water, including secondary treatment and various tertiary treatment options (ozonation, biologically activated carbon filtration, membrane filtration, reverse osmosis, advanced oxidation, chlorination, chloramination). The samples were enriched by solid phase extraction. In most samples the oxidative stress response was far more sensitive than cytotoxicity. The primary and secondary treated effluent exceeded the effect threshold IR 1.5 at a relative enrichment factor (REF) of 1, i.e., the native samples were active. All tertiary treated samples were less potent and their EC(IR1.5) lay between REF 1 and 10. The Nrf2 pathway was induced at a REF of approximately 10 for surface waters and drinking water, and above this enrichment cytotoxicity took over in most samples and quenched the induction. The blank (ultrapure water run through the sample enrichment process) was cytotoxic at an REF of 100, which is the limit of concentrations range that can be evaluated. Treatment typically decreased both the cytotoxicity and oxidative stress response apart from drinking water treatment where chlorination caused an increase in oxidative stress response, presumably due to the formation of disinfection by-products. This study demonstrates the relevance and applicability of the oxidative stress response pathway for water quality monitoring.

Gamma/neutron time-correlation for special nuclear material detection – Active stimulation of highly enriched uranium

DOE PAGES

Paff, Marc G.; Monterial, Mateusz; Marleau, Peter; ...

2014-06-21

A series of simulations and experiments were undertaken to explore and evaluate the potential for a novel new technique for fissile material detection and characterization, the timecorrelated pulse-height (TCPH) method, to be used concurrent with active stimulation of potential nuclear materials. In previous work TCPH has been established as a highly sensitive method for the detection and characterization of configurations of fissile material containing Plutonium in passive measurements. By actively stimulating fission with the introduction of an external radiation source, we have shown that TCPH is also an effective method of detecting and characterizing configurations of fissile material containing Highlymore » Enriched Uranium (HEU). The TCPH method is shown to be robust in the presence of the proper choice of external radiation source. An evaluation of potential interrogation sources is presented.« less

'On-line' analyses of simulated solar wind implantations of terrestrial analogs of lunar materials

NASA Technical Reports Server (NTRS)

Blanford, G. E.; Bergesen, P.; Moeller, W.; Maurette, M.; Monart, B.

1986-01-01

In connection with the establishment of a lunar base, it would be necessary to provide water, and the feasibility to obtain water from solar wind (SW) implanted lunar soils has been considered. In this context, a project involving the examination of materials under conditions of simulated SW irradiation has been initiated. A description is presented of initial results on oligoclase, ilmenite, and simulated lunar glass (SLG). Attention is given to the reaction chamber, the target materials, the saturation concentrations, aspects of water release, depth profiles, thermal release, effects from helium-3 preimplants, mechanisms of possible water release related to direct emission and thermal release, and lunar soil components enriched in trapped SW hydrogen. It is found that ilmenite stores about twice as much deuterium as the other target materials. However, it is unknown whether the small enrichment factor will be sufficient to make the material a potential source of lunar water.

Microbial Enrichment from Six Hydraulic Fracturing Fluids and Biogeochemical Characteristics of Flowback Waters in Oklahoma Shale Formations

NASA Astrophysics Data System (ADS)

Krzmarzick, M. J.; McCutchan, A.; Carroll, J.; Lozano, T.

2017-12-01

Hydraulic fracturing of oil and gas formations has revolutionized the industry, but little is known regarding the interactions of the microbiology in formations and the hydraulic fracturing chemicals used. In the first part of this study, six representative hydraulic fracturing fluids were incubated in bench scale microcosms with surface soils over six months at 1× concentrations used in the field. These fluids differed greatly in terms of biocide, surfactants, corrosion inhibitors and crosslinking agents (if any). The changes in microbial communities were measured by Illumina 16S rRNA gene analysis and quantitative-PCR. As a whole, the microbial communities enriched were significantly varied between fluids, with the magnitude of the difference tightly linked to the total organic carbon of each fluid. Most enriched bacteria heavily grew within just the first couple of weeks, and belonged to genera well-linked to xenobiotic degradation, such as Azospirillum, Ralstonia, and Comamonas. This, combined with bulk parameters such as chemical oxygen demand of the water, indicates that a significant fraction of these fluids are readily degradable, though individual chemicals were not monitored for recalcitrance. In the second component of this work, the flowback waters from sixteen newly completed wells in south-central Oklahoma were monitored over two months for compositions of boron, dissolved solids, BTEX, chloride, and their microbial communities. As expected, dissolved solids increased over time as the flowback waters became more characteristic of the formation waters. In these wells, boron, a carefully measured component of the fracturing fluid for cross-linking applications, was either stable or increased over time. The microbial community characteristics are pending but will be compared between formations, to the chemical data, and to the results in the bench-top degradation study.

Connecting the First Galaxies with Ultrafaint Dwarfs in the Local Group: Chemical Signatures of Population III Stars

NASA Astrophysics Data System (ADS)

Jeon, Myoungwon; Besla, Gurtina; Bromm, Volker

2017-10-01

We investigate the star formation history (SFH) and chemical evolution of isolated analogs of Local Group (LG) ultrafaint dwarf galaxies (UFDs; stellar mass range of {10}2 {M}⊙ < {M}* < {10}5 {M}⊙ ) and gas-rich, low-mass dwarfs (Leo P analogs; stellar mass range of {10}5 {M}⊙ < {M}* < {10}6 {M}⊙ ). We perform a suite of cosmological hydrodynamic zoom-in simulations to follow their evolution from the era of the first generation of stars down to z = 0. We confirm that reionization, combined with supernova (SN) feedback, is primarily responsible for the truncated star formation in UFDs. Specifically, halos with a virial mass of {M}{vir}≲ 2× {10}9 {M}⊙ form ≳ 90 % of stars prior to reionization. Our work further demonstrates the importance of Population III stars, with their intrinsically high [{{C}}/{Fe}] yields and the associated external metal enrichment, in producing low-metallicity stars ([{Fe}/{{H}}]≲ -4) and carbon-enhanced metal-poor (CEMP) stars. We find that UFDs are composite systems, assembled from multiple progenitor halos, some of which hosted only Population II stars formed in environments externally enriched by SNe in neighboring halos, naturally producing extremely low metallicity Population II stars. We illustrate how the simulated chemical enrichment may be used to constrain the SFHs of true observed UFDs. We find that Leo P analogs can form in halos with {M}{vir}˜ 4× {10}9 {M}⊙ (z = 0). Such systems are less affected by reionization and continue to form stars until z = 0, causing higher-metallicity tails. Finally, we predict the existence of extremely low metallicity stars in LG UFD galaxies that preserve the pure chemical signatures of Population III nucleosynthesis.

Materials and Methods for Streamlined Laboratory Analysis of Environmental Samples, FY 2016 Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Addleman, Raymond S.; Naes, Benjamin E.; McNamara, Bruce K.

The International Atomic Energy Agency (IAEA) relies upon laboratory analysis of environmental samples (typically referred to as “swipes”) collected during on-site inspections of safeguarded facilities to support the detection and deterrence of undeclared activities. Unfortunately, chemical processing and assay of the samples is slow and expensive. A rapid, effective, and simple extraction process and analysis method is needed to provide certified results with improved timeliness at reduced costs (principally in the form of reduced labor), while maintaining or improving sensitivity and efficacy. To address these safeguard needs the Pacific Northwest National Laboratory (PNNL) explored and demonstrated improved methods for environmentalmore » sample (ES) analysis. Improvements for both bulk and particle analysis were explored. To facilitate continuity and adoption, the new sampling materials and processing methods will be compatible with existing IAEA protocols for ES analysis. PNNL collaborated with Oak Ridge National Laboratory (ORNL), which performed independent validation of the new bulk analysis methods and compared performance to traditional IAEA’s Network of Analytical Laboratories (NWAL) protocol. ORNL efforts are reported separately. This report describes PNNL’s FY 2016 progress, which was focused on analytical application supporting environmental monitoring of uranium enrichment plants and nuclear fuel processing. In the future the technology could be applied to other safeguard applications and analytes related to fuel manufacturing, reprocessing, etc. PNNL’s FY 2016 efforts were broken into two tasks and a summary of progress, accomplishments and highlights are provided below. Principal progress and accomplishments on Task 1, Optimize Materials and Methods for ICP-MS Environmental Sample Analysis, are listed below. • Completed initial procedure for rapid uranium extraction from ES swipes based upon carbonate-peroxide chemistry (delivered to ORNL for evaluation). • Explored improvements to carbonate-peroxide rapid uranium extraction chemistry. • Evaluated new sampling materials and methods (in collaboration with ORNL). • Demonstrated successful ES extractions from standard and novel swipes for a wide range uranium compounds of interest including UO 2F 2 and UO 2(NO 3) 2, U 3O 8 and uranium ore concentrate. • Completed initial discussions with commercial suppliers of PTFE swipe materials. • Submitted one manuscript for publication. Two additional drafts are being prepared. Principal progress and accomplishments on Task 2, Optimize Materials and Methods for Direct SIMS Environmental Sample Analysis, are listed below. • Designed a SIMS swipe sample holder that retrofits into existing equipment and provides simple, effective, and rapid mounting of ES samples for direct assay while enabling automation and laboratory integration. • Identified preferred conductive sampling materials with better performance characteristics. • Ran samples on the new PNNL NWAL equivalent Cameca 1280 SIMS system. • Obtained excellent agreement between isotopic ratios for certified materials and direct SIMS assay of very low levels of LEU and HEU UO 2F 2 particles on carbon fiber sampling material. Sample activities range from 1 to 500 CPM (uranium mass on sample is dependent upon specific isotope ratio but is frequently in the subnanogram range). • Found that the presence of the UF molecular ions, as measured by SIMS, provides chemical information about the particle that is separate from the uranium isotopics and strongly suggests that those particles originated from an UF6 enrichment activity. • Submitted one manuscript for publication. Another manuscript is in preparation.« less

Synthesis of hydrazide-functionalized hydrophilic polymer hybrid graphene oxide for highly efficient N-glycopeptide enrichment and identification by mass spectrometry.

PubMed

Bai, Haihong; Pan, Yiting; Guo, Cong; Zhao, Xinyuan; Shen, Bingquan; Wang, Xinghe; Liu, Zeyuan; Cheng, Yuanguo; Qin, Weijie; Qian, Xiaohong

2017-08-15

Protein N-glycosylation is one of the most important post-translational modifications, participating in many key biological and pathological processes. Large-scale and precise identification of N-glycosylated proteins and peptides is especially beneficial for understanding their biological functions and for discovery of new clinical biomarkers and therapeutic drug targets. However, protein N-glycosylation is microheterogeneous and low abundant in living organisms, therefore specific enrichment of N-glycosylated proteins/peptides before mass spectrometry analysis is a prerequisite. In this work, we developed a new type of polymer hybrid graphene oxide (GO) by in situ growth of hydrazide-functionalized hydrophilic polymer chains on the GO surface (GO-PAAH) for selective N-glycopeptide enrichment and identification by mass spectrometry. The densely attached and low steric hindrance hydrazide groups as well as the highly hydrophilic nature of GO-PAAH facilitate N-glycopeptide enrichment by the combination of hydrazide capturing and HILIC interaction. Taking advantage of the unique features of GO-PAAH, all of the three N-glycopeptides of bovine fetuin were successfully enriched and identified with significantly enhanced signal intensities from a digest mixture of bovine fetuin and bovine serum albumin at a mass ratio of 1:100, demonstrating the excellent enrichment selectivity of GO-PAAH. Furthermore, a total of 507 N-glycosylation sites and 480 N-glycopeptides in 232 N-glycoproteins were enriched and identified from 10μL of human serum by three replicates using this novel enrichment material, which is nearly two times higher than the commercial hydrazide resin based method (280 N-glycosylation sites, 261 N-glycopeptides and 144 N-glycoproteins in three experiments). Among the identified, 95 N-glycosylation sites were not reported in the Uniprot database, and 106 N-glycoproteins were disease related in the Nextprot database, indicating the potential of this new enrichment material in global mapping of protein N-glycosylation. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of Solvent Extraction Approach to Recycle Enriched Molybdenum Material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tkac, Peter; Brown, M. Alex; Sen, Sujat

2016-06-01

Argonne National Laboratory, in cooperation with Oak Ridge National Laboratory and NorthStar Medical Technologies, LLC, is developing a recycling process for a solution containing valuable Mo-100 or Mo-98 enriched material. Previously, Argonne had developed a recycle process using a precipitation technique. However, this process is labor intensive and can lead to production of large volumes of highly corrosive waste. This report discusses an alternative process to recover enriched Mo in the form of ammonium heptamolybdate by using solvent extraction. Small-scale experiments determined the optimal conditions for effective extraction of high Mo concentrations. Methods were developed for removal of ammonium chloridemore » from the molybdenum product of the solvent extraction process. In large-scale experiments, very good purification from potassium and other elements was observed with very high recovery yields (~98%).« less

Nanogeochemistry: Size-dependent mineral-fluid interface chemistry

NASA Astrophysics Data System (ADS)

Wang, Y.

2012-12-01

Nanostructures and nanometer mineral phases, both widely present in geologic materials, can potentially affect many geochemical processes. It is known that at nanometer scales a material tends to exhibit chemical properties distinct from the corresponding bulk phase. Understanding of this size-dependent property change will help us to bridge the existing knowledge gap between the molecular level understanding and the macro-scale laboratory/field observations of a geochemical process. In this presentation, I will review of the recent progresses in nanoscience and provide a perspective on how these progresses can potentially impact geochemical studies. My presentation will be focused the following areas: (1) the characterization of nanostructures in natural systems, (2) the study of fluids and chemical species in nanoconfinement, (3) the effects of nanopores on geochemical reaction and mass transfers, and (4) the use nanostructured materials for environmental management. I will demonstrate that the nanopore confinement can significantly modify geochemical reactions in porous geologic media. As the pore size is reduced to a few nanometers, the difference between surface acidity constants of a mineral (pK2 - pK1) decreases, giving rise to a higher surface charge density on a nanopore surface than that on an unconfined mineral-water interface. The change in surface acidity constants results in a shift of ion sorption edges and enhances ion sorption on nanopore surfaces. This effect causes preferential enrichment of trace elements in nanopores. I will then discuss the implications of this emergent nanometer-scale property to radionuclide transport and carbon dioxide storage in geologic media. This work was performed at Sandia National Laboratories, which is a multiprogram laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the DOE under contract DE-AC04-94AL8500.

Ternary cobalt-molybdenum-zirconium coatings for alternative energies

NASA Astrophysics Data System (ADS)

Yar-Mukhamedova, Gulmira; Ved', Maryna; Sakhnenko, Nikolay; Koziar, Maryna

2017-11-01

Consistent patterns for electrodeposition of Co-Mo-Zr coatings from polyligand citrate-pyrophosphate bath were investigated. The effect of both current density amplitude and pulse on/off time on the quality, composition and surface morphology of the galvanic alloys were determined. It was established the coating Co-Mo-Zr enrichment by molybdenum with current density increasing up to 8 A dm-2 as well as the rising of pulse time and pause duration promotes the content of molybdenum because of subsequent chemical reduction of its intermediate oxides by hydrogen ad-atoms. It was found that the content of the alloying metals in the coating Co-Mo-Zr depends on the current density and on/off times extremely and maximum Mo and Zr content corresponds to the current density interval 4-6 A dm-2, on-/off-time 2-10 ms. Chemical resistance of binary and ternary coatings based on cobalt is caused by the increased tendency to passivity and high resistance to pitting corrosion in the presence of molybdenum and zirconium, as well as the acid nature of their oxides. Binary coating with molybdenum content not less than 20 at.% and ternary ones with zirconium content in terms of corrosion deep index are in a group ;very proof;. It was shown that Co-Mo-Zr alloys exhibits the greatest level of catalytic properties as cathode material for hydrogen electrolytic production from acidic media which is not inferior a platinum electrode. The deposits Co-Mo-Zr with zirconium content 2-4 at.% demonstrate high catalytic properties in the carbon(II) oxide conversion. This confirms the efficiency of materials as catalysts for the gaseous wastes purification and gives the reason to recommend them as catalysts for red-ox processes activating by oxygen as well as electrode materials for red-ox batteries.

The AMBRE project: Constraining the lithium evolution in the Milky Way

NASA Astrophysics Data System (ADS)

Guiglion, G.; de Laverny, P.; Recio-Blanco, A.; Worley, C. C.; De Pascale, M.; Masseron, T.; Prantzos, N.; Mikolaitis, Š.

2016-10-01

Context. The chemical evolution of lithium in the Milky Way represents a major problem in modern astrophysics. Indeed, lithium is, on the one hand, easily destroyed in stellar interiors, and, on the other hand, produced at some specific stellar evolutionary stages that are still not well constrained. Aims: The goal of this paper is to investigate the lithium stellar content of Milky Way stars in order to put constraints on the lithium chemical enrichment in our Galaxy, in particular in both the thin and thick discs. Methods: Thanks to high-resolution spectra from the ESO archive and high quality atmospheric parameters, we were able to build a massive and homogeneous catalogue of lithium abundances for 7300 stars derived with an automatic method coupling, a synthetic spectra grid, and a Gauss-Newton algorithm. We validated these lithium abundances with literature values, including those of the Gaia benchmark stars. Results: In terms of lithium galactic evolution, we show that the interstellar lithium abundance increases with metallicity by 1 dex from [M/H] = -1 dex to + 0.0 dex. Moreover, we find that this lithium ISM abundance decreases by about 0.5 dex at super-solar metalllicity. Based on a chemical separation, we also observed that the stellar lithium content in the thick disc increases rather slightly with metallicity, while the thin disc shows a steeper increase. The lithium abundance distribution of α-rich, metal-rich stars has a peak at ALi ~ 3 dex. Conclusions: We conclude that the thick disc stars suffered of a low lithium chemical enrichment, showing lithium abundances rather close to the Spite plateau while the thin disc stars clearly show an increasing lithium chemical enrichment with the metallicity, probably thanks to the contribution of low-mass stars. Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/595/A18

The geophysical importance of bubbles in the sea

NASA Technical Reports Server (NTRS)

Cirpriano, R. J.

1982-01-01

Present knowledge of the mechanisms for production and enrichment and film drops by bursting bubbles is summarized, with particular emphasis on the unsolved problems. Sea salt is by far the major constituent cycled through the Earth's atmosphere each year. Bursting bubbles in the oceans appear to be primarily responsible. These salt particles play a role in the formation of maritime clouds, which in turn affect the Earth's radiation budget. Along with the salt are carried various chemical pollutants and potentially pathogenic microorganisms, often in highly enriched form.

Comparative proteomic assessment of matrisome enrichment methodologies

PubMed Central

Krasny, Lukas; Paul, Angela; Wai, Patty; Howard, Beatrice A.; Natrajan, Rachael C.; Huang, Paul H.

2016-01-01

The matrisome is a complex and heterogeneous collection of extracellular matrix (ECM) and ECM-associated proteins that play important roles in tissue development and homeostasis. While several strategies for matrisome enrichment have been developed, it is currently unknown how the performance of these different methodologies compares in the proteomic identification of matrisome components across multiple tissue types. In the present study, we perform a comparative proteomic assessment of two widely used decellularisation protocols and two extraction methods to characterise the matrisome in four murine organs (heart, mammary gland, lung and liver). We undertook a systematic evaluation of the performance of the individual methods on protein yield, matrisome enrichment capability and the ability to isolate core matrisome and matrisome-associated components. Our data find that sodium dodecyl sulphate (SDS) decellularisation leads to the highest matrisome enrichment efficiency, while the extraction protocol that comprises chemical and trypsin digestion of the ECM fraction consistently identifies the highest number of matrisomal proteins across all types of tissue examined. Matrisome enrichment had a clear benefit over non-enriched tissue for the comprehensive identification of matrisomal components in murine liver and heart. Strikingly, we find that all four matrisome enrichment methods led to significant losses in the soluble matrisome-associated proteins across all organs. Our findings highlight the multiple factors (including tissue type, matrisome class of interest and desired enrichment purity) that influence the choice of enrichment methodology, and we anticipate that these data will serve as a useful guide for the design of future proteomic studies of the matrisome. PMID:27589945

Stability of Pycnogenol® as an ingredient in fruit juices subjected to in vitro gastrointestinal digestion.

PubMed

Frontela, Carmen; Ros, Gaspar; Martínez, Carmen; Sánchez-Siles, Luis M; Canali, Raffaella; Virgili, Fabio

2011-01-30

The enrichment of fruit juices with concentrated polyphenolic extracts is an expedient strategy to compensate possible phenolic loss through gastrointestinal processing. Pycnogenol, a standardised procyanidin-rich extract from pine bark, has been proposed as a potential candidate for polyphenol enrichment of foods. In this study the effects of in vitro digestion on the phenolic profile of fruit juices enriched with Pycnogenol were investigated. After in vitro digestion the level of detectable total phenolic compounds (expressed as gallic acid equivalent) was higher in both pineapple and red fruit juices enriched with Pycnogenol than in non-enriched commercial juices. Five phenolic monomeric compounds were identified by high-performance liquid chromatography, namely chlorogenic acid, caffeic acid, ferulic acid, gallic acid and taxifolin, the last two being predominant. In vitro digestion of both Pycnogenol-enriched pineapple and red fruit juices led to a significant (P < 0.05) increase in detectable chlorogenic and ferulic acids, indicating that hydrolysis of more complex molecules occurs. On the other hand, in vitro digestion of non-enriched juices was associated with a decrease in gallic and caffeic acids in pineapple juice and with a decrease in ferulic acid in red fruit juice. In no case did in vitro digestion increase the amount of detectable phenolic compounds in non-enriched juices. The stability of Pycnogenol after in vitro gastrointestinal digestion makes it a good choice for phenolic enrichment of fruit juices. 2010 Society of Chemical Industry.

An Equation Governing Ultralow-Velocity Zones: Implications for Holes in the ULVZ, Lateral Chemical Reactions at the Core-Mantle Boundary, and Damping of Heat Flux Variations in the Core

NASA Astrophysics Data System (ADS)

Hernlund, J. W.; Matsui, H.

2017-12-01

Ultralow-velocity zones (ULVZ) are increasingly illuminated by seismology, revealing surprising diversity in size, shape, and physical characteristics. The only viable hypotheses are that ULVZs are a compositionally distinct FeO-enriched dense material, which could have formed by fractional crystallization of a basal magma ocean, segregation of subducted banded iron formations, precipitation of solids from the outer core, partial melting and segregation of iron-rich melts from subducted basalts, or most likely a combination of many different processes. But many questions remain: Are ULVZ partially molten in some places, and not in others? Are ULVZ simply the thicker portions of an otherwise global thin layer, covering the entire CMB and thus blocking or moderating chemical interactions between the core and overlying mantle? Is such a layer inter-connected and able to conduct electrical currents that allow electro-magnetic coupling of core and mantle angular momentum? Are they being eroded and shrinking in size due to viscous entrainment, or is more material being added to ULVZ over time? Here we derive an advection-diffusion-like equation that governs the dynamical evolution of a chemically distinct ULVZ. Analysis of this equation shows that ULVZ should become readily swept aside by viscous mantle flows at the CMB, exposing "ordinary mantle" to the top of the core, thus inducing chemical heterogeneity that drives lateral CMB chemical reactions. These reactions are correlated with heat flux, thus maintaining large-scale pressure variations atop the core that induce cyclone-like flows centered around ULVZ and ponded subducted slabs. We suggest that turbulent diffusion across adjacent cyclone streams inside a stratified region atop the core readily accommodates lateral transport and re-distribution of components such as O and Si, in addition to heat. Our model implies that the deeper core is at least partly shielded from the influence of strong heat flux variations at the CMB which might otherwise cause problems for producing a geodynamo.

Characterization of Volatile Nylon 6.6 Thermal-Oxidative Degradation Products by Selective Isotopic Labeling and Cryo-GC/MS

NASA Astrophysics Data System (ADS)

Smith, Jonell N.; V. White, Gregory; White, Michael I.; Bernstein, Robert; Hochrein, James M.

2012-09-01

Aged materials, such as polymers, can exhibit modifications to their chemical structure and physical properties, which may render the material ineffective for its intended purpose. Isotopic labeling was used to characterize low-molecular weight volatile thermal-oxidative degradation products of nylon 6.6 in an effort to better understand and predict changes in the aged polymer. Headspace gas from aged (up to 243 d at 138 °C) nylon 6.6 monomers (adipic acid and 1,6-hexanediamine) and polymer were preconcentrated, separated, and detected using cryofocusing gas chromatography mass spectrometry (cryo-GC/MS). Observations regarding the relative concentrations observed in each chromatographic peak with respect to aging time were used in conjunction with mass spectra for samples aged under ambient air to determine the presence and identity of 18 degradation products. A comparison of the National Institute of Standards and Technology (NIST) library, unlabeled, and isotopically labeled mass spectra (C-13 or N-15) and expected fragmentation pathways of each degradation product were used to identify the location of isotopically labeled atoms within the product's chemical structure, which can later be used to determine the exact origin of the species. In addition, observations for unlabeled nylon 6.6 aged in an O-18 enriched atmosphere were used to determine if the source of oxygen in the applicable degradation products was from the gaseous environment or the polymer. Approximations for relative isotopic ratios of unlabeled to labeled products are reported, where appropriate.

Geochemical variations in aeolian mineral particles from the Sahara-Sahel Dust Corridor.

PubMed

Moreno, Teresa; Querol, Xavier; Castillo, Sonia; Alastuey, Andrés; Cuevas, Emilio; Herrmann, Ludger; Mounkaila, Mohammed; Elvira, Josep; Gibbons, Wes

2006-10-01

The Sahara-Sahel Dust Corridor runs from Chad to Mauritania and expels huge amounts of mineral aerosols into the Atlantic Ocean. Data on samples collected from Algeria, Chad, Niger, and Western Sahara illustrate how corridor dust mineralogy and chemistry relate to geological source and weathering/transport history. Dusts sourced directly from igneous and metamorphic massifs are geochemically immature, retaining soluble cations (e.g., K, Na, Rb, Sr) and accessory minerals containing HFSE (e.g., Zr, Hf, U, Th) and REE. In contrast, silicate dust chemistry in desert basins (e.g., Bodélé Depression) is influenced by a longer history of transport, physical winnowing (e.g., loss of Zr, Hf, Th), chemical leaching (e.g., loss of Na, K, Rb), and mixing with intrabasinal materials such as diatoms and evaporitic salts. Mineral aerosols blown along the corridor by the winter Harmattan winds mix these basinal and basement materials. Dusts blown into the corridor from sub-Saharan Africa during the summer monsoon source from deeply chemically weathered terrains and are therefore likely to be more kaolinitic and stripped of mobile elements (e.g., Na, K, Mg, Ca, LILE), but retain immobile and resistant elements (e.g., Zr, Hf, REE). Finally, dusts blown southwestwards into the corridor from along the Atlantic Coastal Basin will be enriched in carbonate from Mesozoic-Cenozoic marine limestones, depleted in Th, Nb, and Ta, and locally contaminated by uranium-bearing phosphate deposits.

The Gaia-ESO Survey: Lithium enrichment histories of the Galactic thick and thin disc

NASA Astrophysics Data System (ADS)

Fu, X.; Romano, D.; Bragaglia, A.; Mucciarelli, A.; Lind, K.; Delgado Mena, E.; Sousa, S. G.; Randich, S.; Bressan, A.; Sbordone, L.; Martell, S.; Korn, A. J.; Abia, C.; Smiljanic, R.; Jofré, P.; Pancino, E.; Tautvaišienė, G.; Tang, B.; Magrini, L.; Lanzafame, A. C.; Carraro, G.; Bensby, T.; Damiani, F.; Alfaro, E. J.; Flaccomio, E.; Morbidelli, L.; Zaggia, S.; Lardo, C.; Monaco, L.; Frasca, A.; Donati, P.; Drazdauskas, A.; Chorniy, Y.; Bayo, A.; Kordopatis, G.

2018-02-01

Lithium abundance in most of the warm metal-poor main sequence stars shows a constarnt plateau (A(Li) 2.2 dex) and then the upper envelope of the lithium vs. metallicity distribution increases as we approach solar metallicity. Meteorites, which carry information about the chemical composition of the interstellar medium (ISM) at the solar system formation time, show a lithium abundance A(Li) 3.26 dex. This pattern reflects the Li enrichment history of the ISM during the Galaxy lifetime. After the initial Li production in big bang nucleosynthesis, the sources of the enrichment include asymptotic giant branch (AGB) stars, low-mass red giants, novae, type II supernovae, and Galactic cosmic rays. The total amount of enriched Li is sensitive to the relative contribution of these sources. Thus different Li enrichment histories are expected in the Galactic thick and thin disc. We investigate the main sequence stars observed with UVES in Gaia-ESO Survey iDR4 catalogue and find a Li-anticorrelation independent of [Fe/H], Teff, and log(g). Since in stellar evolution different α enhancements at the same metallicity do not lead to a measurable Li abundance change, the anticorrelation indicates that more Li is produced during the Galactic thin disc phase than during the Galactic thick disc phase. We also find a correlation between the abundance of Li and s-process elements Ba and Y, and they both decrease above the solar metallicity, which can be explained in the framework of the adopted Galactic chemical evolution models. The full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/A38