289,174 research outputs found
Supplemental macronutrients and microbial fermentation products improve the uptake and transport of foliar applied zinc in sunflower (Helianthus annuus L.) plants. Studies utilizing micro X-ray florescence.
Enhancing nutrient uptake and the subsequent elemental transport from the sites of application to sites of utilization is of great importance to the science and practical field application of foliar fertilizers. The aim of this study was to investigate the mobility of various foliar applied zinc (Zn) formulations in sunflower (Helianthus annuus L.) and to evaluate the effects of the addition of an organic biostimulant on phloem loading and elemental mobility. This was achieved by application of foliar formulations to the blade of sunflower (H. annuus L.) and high-resolution elemental imaging with micro X-ray fluorescence (μ-XRF) to visualize Zn within the vascular system of the leaf petiole. Although no significant increase of total Zn in petioles was determined by inductively-coupled plasma mass-spectrometer, μ-XRF elemental imaging showed a clear enrichment of Zn in the vascular tissues within the sunflower petioles treated with foliar fertilizers containing Zn. The concentration of Zn in the vascular of sunflower petioles was increased when Zn was applied with other microelements with EDTA (commercial product Kick-Off) as compared with an equimolar concentration of ZnSO4 alone. The addition of macronutrients N, P, K (commercial product CleanStart) to the Kick-Off Zn fertilizer, further increased vascular system Zn concentrations while the addition of the microbially derived organic biostimulant "GroZyme" resulted in a remarkable enhancement of Zn concentrations in the petiole vascular system. The study provides direct visualized evidence for phloem transport of foliar applied Zn out of sites of application in plants by using μ-XRF technique, and suggests that the formulation of the foliar applied Zn and the addition of the organic biostimulant GroZyme increases the mobility of Zn following its absorption by the leaf of sunflower
Beneficiation of rare earth minerals from Bokan Mountain: Dotson Ridge ore
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
Weathering product of granite as a possible source of strategic mineral
Several soil samples and granite bedrock samples from Cameron Highlands were analyzed for its elemental concentration using instrumental neutron activation analysis. A total of 34 elements were identified and their concentrations were determined in a single analytical session. Enrichment factor of elemental concentration in the top soil were computed. The findings indicate certain elements were enriched that may facilitates economic beneficiation
PIXE and ToF-SIMS analysis of streaker samplers filters
This paper presents methodological innovations introduced in the characterisation of urban aerosol collected in Italy in a recent campaign. Two complementary ion beam analysis (IBA) techniques were used to analyse Nuclepore filters used in continuous streaker samplers to collect airborne particles in four Italian towns. Na to Pb elemental concentrations were obtained by particle induced X-ray emission (PIXE), while time of flight secondary ion mass spectrometry (ToF-SIMS) produced, on the same samples, time trends for several elements and molecular fragments. In addition, light attenuation measurements were used as a tracer for black carbon. The data produced by these three techniques was merged into a unique data set to address the characterisation of particulate matter sources. Correlations between elemental concentration trends (PIXE) and relative trends for molecular fragments (ToF-SIMS) and black carbon (light attenuation) have been studied by cluster and principal component analysis
Asian dust storm events of spring 2001 and associated pollutants observed in New England by the Atmospheric Investigation, Regional Modeling, Analysis and Prediction (AIRMAP) monitoring network
Between 18 April and 13 May 2001, three statistically extreme dust aerosol events were observed across the entire northeastern United States. High levels of bulk aerosol water-soluble Ca2+ (range = 42–482 pptv) and PM2.5 elemental Ca (range = 19–156 pptv) were observed simultaneously at Atmospheric Investigation, Regional Modeling, Analysis and Prediction (AIRMAP) and Interagency Monitoring of Protected Visual Environments (IMPROVE) stations. On the basis of Ca2+ concentrations, the average bulk dust concentration for all events across all four AIRMAP stations was estimated to be 7.4 μg/m3. There was no evidence of dust outbreaks in North America large enough to explain these events. However, in April 2001, massive dust storms occurred in the Tarim Pendi basin and in the Gobi deserts of southern Mongolia and China. Comparison of elemental ratios of AIRMAP samples to previously reported Asian dust aerosol samples showed that all AIRMAP samples had a chemical composition similar to Asian dust transported over long distances. Within the dust plumes, strong correlations were observed between absorption, scattering, and CO, indicative of an anthropogenic contribution including elemental carbon and SO42− aerosols. Aerosol NO3− was also highly elevated during event days, most likely due to uptake of HNO3 by the dust during transport. A comparison of dust plumes sampled by AIRMAP to those sampled off the Asian coast during the TRACE-P airborne mission and on the U.S. west coast, strongly suggested entrainment of additional pollutants (e.g., CO, aerosol NO3−, and SO42−) as the dust plumes were transported over North America
Airborne Particles in Museums
Presents one in a series of research activities aimed at a better understanding of the origin and fate of air pollution within the built environment
Mineral composition through soil-wine system of portuguese vineyards and its potential for wine traceability
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
Structural and magnetic properties of Pr-alloyed MnBi nanostructures
The structural and magnetic properties of Pr-alloyed MnBi (short MnBi-Pr)
nanostructures with a range of Pr concentrations have been investigated. The
nanostructures include thin films having Pr concentrations 0, 2, 3, 5 and 9
atomic percent and melt-spun ribbons having Pr concentrations 0, 2, 4 and 6
percent respectively. Addition of Pr into the MnBi lattice has produced a
significant change in the magnetic properties of these nanostructures including
an increase in coercivity and structural phase transition temperature, and a
decrease in saturation magnetization and anisotropy energy. The highest value
of coercivity measured in the films is 23 kOe and in the ribbons is 5.6 kOe.
The observed magnetic properties are explained as the consequences of competing
ferromagnetic and antiferromagnetic interactions
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