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Radon Concentration Measurements in Gattar Uranium Prospect, Northern Eastern Desert, Egypt  [PDF]
Naglaa Fahmi
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2019, DOI: 10.4236/jasmi.2019.91001
Abstract: The concentration of Radon in mines varies tremendously according to the country rock, type of mineralization and area. Ventilation is also an important factor. The absence of ventilation in mines tends to allow a higher concentration of Radon to build up. This is very dangerous for the miners work inside. In this present work, the radon gas concentration is practically measured in closed uranium prospect mine located at Gabal (G.) Gattar. CR-39 solid state nuclear track detector technique is used. It is found that the radon concentration is around 80 kBq m-3 and an effective ventilation rates should be applied if there will be further works in the future.
Characterization of a Post Orogenic A-Type Granite, Gabal El Atawi, Central Eastern Desert, Egypt: Geochemical and Radioactive Perspectives  [PDF]
Khairiya M. Fawzy
Open Journal of Geology (OJG) , 2017, DOI: 10.4236/ojg.2017.71007
Abstract: The alkali feldspar granite of Gabal El Atawi is post orogenic granite originated from subalkaline magma in extensional suite. It is developed within plate tectonic setting and has A2-type character which generated from apparent crustal source. The petrographic, geochemical and radioactive characteristics of El Atawi granite meet and fulfill the requirements of being fertile granite and it can be considered as promising uraniferous granite. Fluid inclusion studies of the altered granite elucidated two different solutions acting on the host granitic pluton. The first is NaCl-CaCl low temperature fluid with a wide range of salinity. The second is high temperature and salinity Fe-Mg-Na chloride solution. Different fractures in the granite acted as good channels for the hydrothermal fluids that leached uranium from its bearing minerals disseminated all over the host granite and redeposited it in the alteration zones.
The Petrography, Mineralography and Microprobe Analysis on New Exploratory Excavation Phase in Sarcheshmeh Copper Mine Pit and Comparing Them with Existing Data from the Other Area in South West Sarcheshmeh  [PDF]
Mehdi Abdollahy Riseh, Mansur Vosooghi Abedini, Mohammad Hashem Emami, Seyed Jamal Sheikh Zakariaei
Open Journal of Geology (OJG) , 2017, DOI: 10.4236/ojg.2017.72011
Abstract: Kerman region where Sarcheshmeh zone is located includes the end part of Uremia-Dokhtar Zone. Extrusive igneous group in Sarcheshmeh is as follows: 1) andesite and 2) rhyodacite. The group of intrusive igneous rocks includes 1) porphyry granite, 2) porphyry granodiorite, and 3) porphyry diorite. Nochoon mine is located at 4 km of southwest of Sarcheshmeh copper mine and it comprises of a group of extrusive igneous rocks as follows: 1) andesite, and 2) dacite. Based on results of microprobe analysis, pyroxene mineral’s composition in these rocks of diopside and augite indicates amphiboles of composite zone of magnesium hosting type and existing plagioclases in regional rock for labradorite and bitonit composition. The most common compounds are chlorite with formula among antigorite and amosite. Comparison of magnetite mineralization in Sarcheshmeh and Nochoon indicates vein mineralization in Nochoon and disseminated granulation in Sarcheshmeh and particularly concerning to chalcopyrite, Nochoon includes more veins than Sarcheshmeh.
Interpretation of heterogeneity effects in synchrotron X-ray fluorescence microprobe data
Mavrik Zavarin, Harvey E Doner
Geochemical Transactions , 2002, DOI: 10.1186/1467-4866-3-51
Abstract: A synchrotron X-ray fluorescence microprobe (SXRFM) has been in use at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, since March 1986.[1] New higher flux third generation synchrotron X-ray sources such as the Advanced Photon Source (APS), Argonne National Laboratory, and several others have more recently become available for SXRFM studies. Due to the high brightness of these sources, elemental mapping can be accomplished at the sub-ppm level. In addition, focusing techniques (e.g. multilayer Kirkpatrick-Baez mirrors,[2,3] zone plates and tapered capillaries) can now reduce the beam to < 1 μm2 spot sizes to achieve unprecedented spatial resolutions. Though techniques such as the electron microprobe, secondary ion mass spectro-metry, and others may have similar spatial resolution or similar detection limits in some cases, one of the most appealing aspects of the SXRFM is that samples can be run at atmospheric pressures and temperatures which is particularly important for characterization of environmentally sensitive samples.[4] SXRFM can also provide information on element speciation when fluorescence is measured as a function of primary X-ray energy. These advantages make SXRFM an ideal tool for 2-D elemental mapping of environmental samples.The use of SXRFM in the analysis of environmental samples has been particularly popular due to the low detection limits for environmentally significant elements and little sample treatment which reduces the possibility for sample preparation effects. Geological investigations have included trace element analysis of extraterrestrial materials, sediments, and fluid inclusions,[1,5] as well as oxidation state analysis of minerals.[6] SXRFM has also been used in quantification of various environmental problems such as radionuclide migration through sediments, redox-controlled mobility of toxic metals in soils, and plant–metal interactions.[7,8] However, due to the highly heterogeneous matrix that usual
Characterisation of the primary X-ray source of an XPS microprobe Quantum 2000  [PDF]
U. Scheithauer
Physics , 2014, DOI: 10.1016/j.elspec.2014.03.009
Abstract: The outstanding design feature of an XPS microprobe Quantum 2000 is the double focussing ellipsoidally shaped quartz monochromator of the X-ray source. This device monochromatizes the Alk{\alpha} radiation and refocuses the X-rays from the Al anode to the sample surface. This way, on one hand a variation of the diameter of the X-ray generating electron beam allows to vary the X-ray beam diameter on the sample surface. On the other hand a scanning of the electron beam across the Al anode scans the X-ray beam across the sample surface. The X-ray source was characterized in detail. The lateral dependency of the primary X-ray intensity and the peaks FWHM were measured as function of the position within the electrostatically rasterable scan area. Additionally, the focussing quality of the monochromator was determined. Therefore the lateral intensity distribution within the primary X-ray beam was estimated far below the 1% intensity level.
Microprobe Mapping of Rare Earth Element Distribution in Round Top Yttrofluorite Deposit  [PDF]
Nicholas E. Pingitore Jr., Margaret Piranian, Lorraine M. Negron, Daniel Gorski
Advances in Materials Physics and Chemistry (AMPC) , 2018, DOI: 10.4236/ampc.2018.81002
Abstract: The electron microprobe maps the spatial distribution of elements in a rock at a sub-mineral-grain scale to provide a basis for understanding mineralization processes and to determine optimal strategies for extraction of valuable target elements. Round Top Mountain (near the town of Sierra Blanca, Hudspeth County, west Texas, USA) is a peraluminous rhyolite laccolith that is homogeneously mineralized at over 500 ppm rare earths, more than 70% of which are yttrium and heavy rare earths (YHREEs). The massive deposit is exposed at the surface as a mountain some 2 km in diameter and 375 m in height. Round Top Mountain also contains Li, Be, U, Th, Nb, Ta, Ga, Rb, Cs, Sn, and F. The valuable YHREEs are hosted in yttrofluorite, which is soluble in dilute sulfuric acid. Texas Mineral Resources Corporation proposes to surface mine, crush, and heap leach the deposit. The distribution of YHREEs, and that of other trace elements, is remarkably homogeneous at outcrop drill hole scale. Here we document that YHREE mineralization appears pervasive through the rhyolite at a millimeter scale. Back scattered electron (BSE) and characteristic X-ray maps reveal the fine grain size and apparently random and dispersed spatial distribution of the yttrofluorite that hosts Round Top’s valuable YHREEs. The yttrofluorite grains do not appear to cluster at special mineralized locations, e.g., in pores or along cracks in the rhyolite. The same is apparently true of such other potentially valuable minerals as cassiterite and uranium species. These findings confirm that the distribution of YHREEs in Round Top Mountain rhyolite is homogeneous through different orders of magnitude of scale, i.e., from outcrop (as seen in the companion work in this volume) to sub-thin section. The material thus is ideal for a heap leach operation where homogeneous feedstock is crucial to consistent and economic operation. The findings also confirm and explain why mechanical separation would prove very difficult and expensive due to the astronomical number of yttrofluorite grains in even a golf-ball-size piece of Round Top rhyolite.
Younger Dryas Comet 12,900 BP  [PDF]
Hermann G. W. Burchard
Open Journal of Geology (OJG) , 2017, DOI: 10.4236/ojg.2017.72013
Abstract: Deep troughs in Lake Superior support the hypothesis of Younger Dryas Boundary (YDB) comet impact 12,900 BP. The impact theory explains the megafauna extinction, a black mat across the Northern hemisphere, nanodiamonds, platinum and iridium, and the enigmatic Carolina Bays (CB). While the CB were thought to predate Clovis cultural remains, but this must now be seen as spurious as the CB occur on Long Island, an LGM terminal moraine & on end-glacial flood plains, according to Allen West. The CB sand rims are exceptionally pure quartz with large phenocrysts, and also they exude hydrogen (H). This suggests origin from deep granitic plutons, the granite typically being over-saturated with silica. When the Russian Kola Peninsula Superdeep Borehole had reached 40,000 ft, H was boiling from the borehole. This H is among volatiles copiously dissolved in the mantle, from the primitive solar nebula. The granite is from the Lake Superior Province. Lakes Superior, Michigan, Huron & Ontario have deep holes, reaching to below sea level. Bathymetry exhibits a ~145 km circular contour in Eastern L. Superior, where deep troughs occur, eroded in breccias infilling impact explosion cavities many kms deep, as much as 15 to 35 km, the comet fragments coming in from the NW, with the holes lined up along the trajectory. This was an oblique impact with an extremely low angle of incidence, so the ejected granite quartz sands ended up in the CB along the Eastern seaboard principally.
Use of X-ray microprobe to diagnose bone tissue demineralization after caffeine administration Use of X-ray microprobe to diagnose bone tissue demineralization after caffeine administration  [cached]
Marek Tomaszewski,Grazyna Olchowik,Monika Tomaszewska,Franciszek Burdan
Folia Histochemica et Cytobiologica , 2012, DOI: 10.5603/19754
Abstract: Caffeine is a methylxanthine which permeates the placenta. In studies on animals, it has been shown to produce teratogenic and embryotoxic effects in large doses. The objective of this study was to assess the influence of caffeine on the development of bone tissue, with particular reference to elemental bone composition using an X-ray microprobe. The research was conducted on rats. The fertilized females were randomly divided into an experimental and a control group. The experimental group was given caffeine orally in 30 mg/day doses from the 8th to the 21st day of pregnancy, while the control group was given water. The fetuses were used to assess the growth and mineralization of the skeleton. On the basis of double dyeing, a qualitative analysis of the bone morphology and mineralization was conducted. For calcium and potassium analysis, an X-ray microprobe was used. In 67 fetuses from the experimental group, changes in skeleton staining with the alcian-alizarin method were noticed. The frequency of the development of variants in the experimental group was statistically higher. In the experimental group, a significant decrease in the calcium level, as well as an increase in the potassium level, was observed. The X-ray microprobe’s undoubted advantage is that is offers a quick qualitative and quantitative analysis of the elemental composition of the examined samples. Employing this new technique may furnish us with new capabilities when investigating the essence of the pathology process. Caffeine is a methylxanthine which permeates the placenta. In studies on animals, it has been shown to produce teratogenic and embryotoxic effects in large doses. The objective of this study was to assess the influence of caffeine on the development of bone tissue, with particular reference to elemental bone composition using an X-ray microprobe. The research was conducted on rats. The fertilized females were randomly divided into an experimental and a control group. The experimental group was given caffeine orally in 30 mg/day doses from the 8th to the 21st day of pregnancy, while the control group was given water. The fetuses were used to assess the growth and mineralization of the skeleton. On the basis of double dyeing, a qualitative analysis of the bone morphology and mineralization was conducted. For calcium and potassium analysis, an X-ray microprobe was used. In 67 fetuses from the experimental group, changes in skeleton staining with the alcian-alizarin method were noticed. The frequency of the development of variants in the experimental group was statistically
Mineral chemistry of polymetallic mineralization associated with altered granite, Hangaliya area, South Eastern Desert, Egypt
Mohamed F. Raslan,Mohamed A. Ali
Geologija , 2010,
Abstract: The Hangaliya gold deposit, located in the South Eastern Desert of Egypt, comprises a series of milky quartzveins along NW-trending Hangaliya shear zone, cutting through granitic rocks of Gabal Nugrus monzogranite. Thisshear zone, along with a system of discrete shear and fault zones, formed in the late deformation history of the area.The quartz vein emplacement took place under a brittle-ductile shear regime. Auriferous quartz veins are slightlysheared and boudinaged within the shear zone, especially in the hematized granite. Hydrothermal alteration ispervasive in the granitic wall rocks including sericitization, chloritization, fluoritization, sulphidization and minorcarbonatization. The altered zones and associating quartz veins contain sulphides, gold, silver, cobalt, bismuth, anduraninite minerals.The Hangaliya gold veins include gold, silver, cobaltite, native bismuth, chalcopyrite, pyrite, galena, ferrocolumbite,fergusonite and uraninite. The Au-ore occurs in the quartz veins and adjacent wall rocks as disseminationin chalcopyrite and pyrite. Presence of refractory native silver, bismuth and cobalt in chalcopyrite is inferredfrom microprobe analyses. Wall rock sulphidization also likely contributed to destabilising the gold-silver, cobalt,bismuth assemblages and precipitation of the minerals in the hydrothermal alteration zone adjacent to the quartzveins. Gold occurs in two main modes: “invisible gold” in sulphides and native gold. Most of the “invisible gold”occurs in chalcopyrite and bismuth. The altered granites in the Hangaliya shear zone are enriched in Au, Ag, Bi, Co,and Ni with chalcopyrite, which suggests derivation of these metals from serpentinites due to interaction with thefelsic Nugrus granite.
Use of a beta microprobe system to measure arterial input function in PET via an arteriovenous shunt in rats
Geoff Warnock, Mohamed-Ali Bahri, David Goblet, Fabrice Giacomelli, Christian Lemaire, Joel Aerts, Alain Seret, Xavier Langlois, Andre Luxen, Alain Plenevaux
EJNMMI Research , 2011, DOI: 10.1186/2191-219x-1-13
Abstract: In the present study, a light-insensitive beta microprobe with a temporal resolution of up to 1 s was used in combination with a pump-driven femoral arteriovenous shunt to measure IF in rats. The shunt apparatus was designed such that the placement of the beta microprobe was highly reproducible. The probe-derived IF was compared to that obtained from manual sampling at 5-s intervals and IF derived from a left ventricle VOI in a dynamic PET image of the heart.Probe-derived IFs were very well matched to that obtained by "gold standard" manual blood sampling, but with an increased temporal resolution of up to 1 s. The area under the curve (AUC) ratio between probe- and manually derived IFs was 1.07 ± 0.05 with a coefficient of variation of 0.04. However, image-derived IFs were significantly underestimated compared to the manually sampled IFs, with an AUC ratio of 0.76 ± 0.24 with a coefficient of variation of 0.32.IF derived from the beta microprobe accurately represented the IF as measured by blood sampling, was reproducible, and was more accurate than an image-derived technique. The use of the shunt removed problems of tissue-background activity, and the use of a light-tight probe with minimal gamma sensitivity refined the system. The probe/shunt apparatus can be used in both microprobe and PET studies.With the increased popularity of positron emission tomography (PET) imaging in small animals, the use of kinetic modeling to study physiological function has become widespread. Many kinetic models, for example those used in the quantitative measurement of local cerebral glucose metabolism or measurement of radiotracer receptor binding, require the accurate measurement of the time-activity curve of the tracer in plasma, known as the input function (IF). In the case of the widely used tracer 18F-fluorodeoxyglucose (FDG), the time-activity curve of tracer uptake in a specific brain region, combined with the IF, can be used in a classical modeling approach to calculate the
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