534,212 research outputs found

    Mineral composition through soil-wine system of portuguese vineyards and its potential for wine traceability

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    The control of geographic origin is one of a highest priority issue regarding traceability and wine authenticity. The current study aimed to examine whether elemental composition can be used for the discrimination of wines according to geographical origin, taking into account the effects of soil, winemaking process, and year of production. The elemental composition of soils, grapes, musts, and wines from three DO (Designations of Origin) and for two vintage years was determined by using the ICP-MS semi-quantitative method, followed by multivariate statistical analysis. The elemental composition of soils varied according to geological formations, and for some elements, the variation due to soil provenance was also observed in musts and wines. Li, Mn, Sr and rare-earth elements (REE) allowed wine discrimination according to vineyard. Results evidenced the influence of winemaking processes and of vintage year on the wine’s elemental composition. The mineral composition pattern is transferred through the soil-wine system, and differences observed for soils are reflected in grape musts and wines, but not for all elements. Results suggest that winemaking processes and vintage year should be taken into account for the use of elemental composition as a tool for wine traceability. Therefore, understanding the evolution of mineral pattern composition from soil to wine, and how it is influenced by the climatic year, is indispensable for traceability purposesinfo:eu-repo/semantics/publishedVersio

    Ion-beam analysis of meteoritic and lunar samples

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    Charged particle-induced nuclear reactions were used in the following problems: the determination of elemental abundances of boron and fluorine in carbonaceous chondritic meteorites; the identification of products of lunar vulcanism; and the study of solar wind-implanted atoms in lunar materials. The technique was seen as an important supplement to other methods of elemental and isotopic analysis. This was especially true for cases involving light elements at very low concentrations or where high resolution depth distribution information was needed in non-destructive analysis

    Beneficiation of rare earth minerals from Bokan Mountain: Dotson Ridge ore

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    Thesis (M.S.) University of Alaska Fairbanks, 2014The purpose of this research work was to study the beneficiation of rare earth ore of the Bokan Mountain -- Dotson Ridge deposit, located near Ketchikan, Alaska. Rare earth element (REE) composite ore samples from the Bokan Mountain -- Dotson Ridge deposit were tested using gravity concentration, magnetic separation, flotation, and leaching techniques to separate the REE. The composite ore sample was a product of a preliminary x-ray sorting process. Qualitative electron microprobe analysis of the ore showed that most of the REE minerals in the ore were silicate minerals. Since the electron microprobe analysis samples were coated with carbon during sample preparation, the carbon element was inactivated for analysis. Because of this, carbonate compounds of minerals' particles could not be detected. 95% of the REE mineral particles appear to be smaller than about 10 μm in size (about 100 μm² in area). For the gravity concentration, light rare earth elements (LREE) and heavy rare earth elements' (HREE) individual elemental recovery values were in the ranges of 49.6-52.8% and 46.3-48.8%, respectively, at 25% of mass yield. In order to separate a larger amount of the REE, a wet high intensity magnetic separation (WHIMS) test was carried out on tailings of the gravity concentration tests. The HREE individual elemental recovery values ranged from 56.3-63.1% at 37% mass yield, while LREE individual elemental recovery values were in the 57.9% - 59.1% range. For the combined gravity and magnetic separation processes, the net individual elemental recovery values of the LREE and the HREE were in the range of 79.6-80.5% and 76.5-80.9%, respectively. The combined mass yield of the gravity and magnetic separation processes was 3%. Direct leaching tests conducted on the composite ground ore feed yielded high individual elemental recovery values of 90-92% of the LREE. The HREE individual elemental recovery values ranged from 56.5-87.3%. In the leaching, 20% HCl was used in the 1st and 2nd stages with a duration of 2 hrs in each stage at 90°C. The solid percentage of the leach slurry was 20% w/w. The composite ground ore sample was tested in conventional flotation using a 2.0 L capacity Denver cell. In the flotation, 0.05 kg/tonne of Cytec Aero 6493 collector, 0.05 kg/tonne of Cytec Aero Froth 88, and 0.1 kg/tonne of sodium metasilicate as a depressant were used. Pulp pH was set around 9. Results showed individual elemental recovery values in the range of 44.6-50.4% or the LREE. The HREE individual elemental recovery values ranged from 27.9-44.5%. The mass yield of the flotation was 23%. The flotation recoveries reported here are significantly lower than what was achieved previously. For the Leach after flotation process, leaching was conducted on the first concentrate of flotation. Individual elemental recovery values of the LREE and HREE were 94.7-96.5% and 61.1-90.5%, respectively. The concentrate was leached using 20% HCl in both the 1st and 2nd stages, with a duration of 2 hrs in each stage at 90°C. Flotation/Leach process net recoveries of LREE by individual elemental values ranged from 42.2-48.5%. HREE net recoveries by individual elemental values ranged from 17.1-41.4%.Chapter 1 Introduction and Objectives -- Chapter 2 Literature Review -- 2.1 Gravity separation of REE ore -- 2.2 Magnetic separation of REE ore -- 2.3 Froth flotation of REE ore -- 2.4 Leaching of REE -- 2.5 Mineral processing of Bokan Mountain: Dotson Ridge REE ore -- 2.5.1 Mineralogical property -- 2.5.2 Froth flotation -- 2.5.3. Leaching -- 2.5.3.1 Direct leaching -- 2.5.3.2 Leach after flotation -- Chapter 3 Methods and Materials -- 3.1 Materials -- 3.2 Gravity separation tests -- 3.3 Wet high intensity magnetic separation tests -- 3.4 Froth flotation tests -- 3.5 Leaching tests -- 3.5.1 Direct leaching -- 3.5.2 Leach after flotation -- 3.6 Electron microprobe analysis of REE mineralogy -- Chapter 4 Results and Discussion -- 4.1 Gravity separation -- 4.2 Wet high intensity magnetic separation -- 4.3 Froth flotation -- 4.4 Leaching -- 4.4.1 Direct leaching -- 4.4.2 Leach after flotation -- 4.5 Electron microprobe analysis -- 4.5.1 Mineralogy of the ore -- 4.5.2 Mineralogy of flotation concentrate -- Chapter 5 Conclusions and Recommendation -- 5.1 Conclusions -- 5.2 Recommendation for future work -- References -- Appendices

    Global petrologic variations of the Moon: A ternary-diagram approach

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    A ternary-diagram approach is used to show on a single map as much detailed geochemical information concerning petrologic variations within the lunar crust as is possible. The classification map shows the global spatial distributions of end-member compositions, the transitional spatial relations between end-member compositions, and quantitative estimates of relative proportions of each end member at each pixel location within the orbital groundtracks. The use of elemental ratios in this analysis, instead of the commonly used elemental bivariate diagrams, shows geologic information that is otherwise hidden in individual elemental databases

    A method for determining elements for elemental signature analysis of groundwater and treated Lake Mead water

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    Elemental signature analysis (ESA) is a term that describes the use of the presence/absence or relative abundance of elements in samples. Several studies have been performed on the identification of these elemental signatures or fingerprints of water using inductively coupled plasma mass spectrometry (ICP-MS); Lake Mead is the primary water supply for the Las Vegas Valley. During the summer months, several large underground aquifers are used to supplement the Lake Mead water supply. Treated Lake Mead water is recharged during the low demand months to several of these aquifers. The Las Vegas Valley is surrounded by many private groundwater wells that tap smaller aquifers. Water quality varies between these aquifers. Many of the wells are exposed to controlled or uncontrolled contamination from a variety of sources, including cross-contamination between aquifers; Aquifers were identified by using the available literature and data obtained from ICP atomic emission spectrometer (ICP-AES) trace-metal analysis of water from 62 private wells in the Las Vegas Valley; Private groundwater wells in the northwest, southwest, and southeast areas of the Las Vegas Valley and water from three recharge wells were sampled and analyzed by ICP-AES for 14 elements and by ICP-MS for 58 elements; Element concentrations obtained using ICP-MS and statistical analysis were used to identify elements for use as an elemental signature of the treated Lake Mead water used for recharge of the Las Vegas Valley aquifers. Ratios of the elements identified as suitable markers for elemental signature analysis, were determined to identify potential trends in the data between areas and treated Lake Mead water; Results of the study indicate that element concentrations vary significantly between areas in the Las Vegas Valley, thus allowing them to be used as criteria to distinguish between two water sources. (Abstract shortened by UMI.)

    Elemental composition and oxidation of chamber organic aerosol

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    Recently, graphical representations of aerosol mass spectrometer (AMS) spectra and elemental composition have been developed to explain the oxidative and aging processes of secondary organic aerosol (SOA). It has been shown previously that oxygenated organic aerosol (OOA) components from ambient and laboratory data fall within a triangular region in the f_(44) vs. f_(43) space, where f_(44) and f_(43) are the ratios of the organic signal at m/z 44 and 43 to the total organic signal in AMS spectra, respectively; we refer to this graphical representation as the "triangle plot." Alternatively, the Van Krevelen diagram has been used to describe the evolution of functional groups in SOA. In this study we investigate the variability of SOA formed in chamber experiments from twelve different precursors in both "triangle plot" and Van Krevelen domains. Spectral and elemental data from the high-resolution Aerodyne aerosol mass spectrometer are compared to offline species identification analysis and FTIR filter analysis to better understand the changes in functional and elemental composition inherent in SOA formation and aging. We find that SOA formed under high- and low-NO_x conditions occupy similar areas in the "triangle plot" and Van Krevelen diagram and that SOA generated from already oxidized precursors allows for the exploration of areas higher on the "triangle plot" not easily accessible with non-oxidized precursors. As SOA ages, it migrates toward the top of the triangle along a path largely dependent on the precursor identity, which suggests increasing organic acid content and decreasing mass spectral variability. The most oxidized SOA come from the photooxidation of methoxyphenol precursors which yielded SOA O/C ratios near unity. α-pinene ozonolysis and naphthalene photooxidation SOA systems have had the highest degree of mass closure in previous chemical characterization studies and also show the best agreement between AMS elemental composition measurements and elemental composition of identified species within the uncertainty of the AMS elemental analysis. In general, compared to their respective unsaturated SOA precursors, the elemental composition of chamber SOA follows a slope shallower than −1 on the Van Krevelen diagram, which is indicative of oxidation of the precursor without substantial losss of hydrogen, likely due to the unsaturated nature of the precursors. From the spectra of SOA studied here, we are able to reproduce the triangular region originally constructed with ambient OOA compents with chamber aerosol showing that SOA becomes more chemically similar as it ages. Ambient data in the middle of the triangle represent the ensemble average of many different SOA precursors, ages, and oxidative processes

    Classification of Hungarian medieval silver coins using x-ray fluorescent spectroscopy and multivariate data analysis

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    A set of silver coins from the collection of Déri Museum Debrecen (Hungary) was examined by X-ray fluorescent elemental analysis with the aim to assign the coins to different groups with the best possible precision based on the acquired chemical information and to build models, which arrange the coins according to their historical periods. Results: Principal component analysis, linear discriminant analysis, partial least squares discriminant analysis, classification and regression trees and multivariate curve resolution with alternating least squares were applied to reveal dominant pattern in the data and classify the coins into several groups. We also identified those chemical components, which are present in small percentages, but are useful for the classification of the coins. With the coins divided into two groups according to adequate historical periods, we have obtained a correct classification (76-78%) based on the chemical compositions. Conclusions: X-ray fluorescent elemental analysis together with multivariate data analysis methods is suitable to group medieval coins according to historical periods. Keywords: X-ray fluorescence spectroscopy, Multivariate techniques, Coin, Silver, Middle age

    2-{2,6-Bis[bis(4-fluorophenyl)methyl]-4-chlorophenylimino} -3-aryliminobutylnickel(II) bromide complexes: Synthesis, characterization, and investigation of their catalytic behavior

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    The series of 2-{2,6-bis[di(4-fluorophenyl)methyl]-4-chlorophenylimino}-3- aryliminobutane derivatives (L1-L5) and their nickel(II) dibromide complexes (Ni1-Ni5) were synthesized, and all organic compounds were fully characterized by the Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy and by elemental analysis, while the nickel complexes were characterized by FT-IR spectroscopy, elemental analysis, as well as by single-crystal X-ray diffraction for two representative examples, namely Ni1 and Ni4. A distorted tetrahedral geometry was observed for these four-coordinate nickel complexes. Upon the activation with either Methylaluminoxane or modified methylaluminoxane as co-catalyst, all nickel complex precatalysts showed very high activity toward ethylene polymerization with activities of up to 10 7 g(PE)·mol -1 (Ni)·h -1 , and afforded highly branched polyethylene with a bimodal distribution. © 2014 Elsevier B.V

    Laser microprobe facility used in the elemental analysis of small feature of a sample

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    Laser microprobe facility is effective in the elemental analysis of small areas of heterogeneous samples. The instrument uses the focused beam of a pulsed laser to evaporate a small volume of material from a relatively massive sample

    Elemental surface analysis at ambient pressure by electron-induced x-ray fluorescence

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    The development of a portable surface elemental analysis tool, based on the excitation of characteristic x rays from samples at ambient pressure with a focused electron beam is described. This instrument relies on the use of a thin electron transmissive membrane to isolate the vacuum of the electron source from the ambient atmosphere. The major attributes of this instrument include rapid (several minutes) spectrum acquisition, nondestructive evaluation of elemental composition, no sample preparation, and high-to-medium (several hundreds µm) spatial resolution. The instrument proof-of-principle has been demonstrated in a laboratory setup by obtaining energy dispersive x-ray spectra from metal and mineral samples
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