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The occurrence and mineralogical characteristics of ishikawaite in unzoned pegmatite hosted in the monzogranite of Gabal Samma area, Southeastern Sinai, Egypt are investigated. Ishikawaite occurs in highly radioactive pegmatitic bodies in which the averages of uranium and thorium contents are (211&1480 ppm respectively). The mineral presents in association with uranophane, thorite, uranothorite, columbite, betafite, metamict zircon and fluorite. The pegmatites occur as pockets (5x10m) and dykes (1x20m) hosted in the monzogranites. The investigated mineral is generally black to dark brown in color, forming anhedral grains with a black to brown streak and opaque with vitreous luster. The mineralogy and geochemistry of the studied ishikawaite were determined using microscopic examination as well as quantitative analysis by ICP-MS. The ICP-MS shows the average oxides composition: 47.61% Nb 2 O 5 , 22.83% UO 2 , 6.06% Fe 2 O 3 , 5.44% Ta 2 O 5 , 4.69% REE 2 O 3 , 4.34% ThO 2 , 3.23% CaO and 2.99% Y 2 O 3. The minor to trace elements include Mn, Ti, Al and Zr. The calculated empirical formula is (U 0.231 Th 0.045 Fe +3 0.207 Ca 0.157 Y 0.071 REE 0.06 Mn 0.048 Al 0.021 Na 0.015 K 0.007 Zr 0.007 Mg 0.002 Hf 0.001) ∑0.883 (Nb 0.976 Ta 0.067 Ti 0.028) ∑ 1.071 O 4. The simplified formula is (U, Th, Fe +3 , Ca, Y, REE) (Nb, Ta, Ti) O 4. The formula of the study ishikawaite is non stoichiometric and show some deficiency in the A-site relative to the B-site. Metamictization, a common feature of ishikawaite is suspected to be the main reason for this deviation from ideal stoichiometry. The deviations of Y/Ho and Zr/Hf ratios of the investigated ishikawaite from chondiritic trace-element ratios are characteristic for strong magmatic with hydrothermal alteration.

The present work aims to study the mineralogy as well as the radioactivity of the acidic Dokhan volcanic in Gabal Nuqara area to identify the minerals that responsible for the radioactivity. The Dokhan volcanic of Gabal Nuqara, Central Eastern Desert are related to fissure-type eruption and are subdivided into intermediate and acidic volcanics. The acidic Dokhan volcanics rocks are located as two elongated flows of rhyolite, dacite and their tuffs, trending NW-SE direction and cut by younger granites and younger gabbros. Radiomatically, tuffs and dacite rocks show low radioactivity, while the concerned rhyolite exhibits relatively high eTh and eU contents (140 ppm and 89 ppm in average respectively). Moreover, an anomalous content was recorded in rhyolite rocks where eTh and eU contents are 745 ppm and 280 ppm in average, respectively. The detailed mineralogical studies, using ESEM and XRD techniques, indicate the presence of some primary radioactive minerals that are responsible for the radioactivity of the Nuqara rhyolites (e.g. thorite and uranothorite). Furthermore, samarskite, zircon and allanite occur as uraniferous accessory minerals. The mineral chemistry by EPMA analysis of thorite reflects the main following components; ThO 2 (38 %), SiO 2 (33 %) and UO 2 (6 %), while the main constituents of uranothorite are ThO 2 (40 %), SiO 2 (20 %), and UO 2 (12 %). Beside, the studied zircon crystals display a large chemical variability between core and rim. Zircon and thorite from Nuqara rhyolite are demonstrably magmatic origin, can be attributed concentrated in the rhyolite extrusive rocks in the late stage of the volcanoes in the study area.

The studied monzogranites and alkali-feldspar granites of W. Hawashia, North Eastern Desert of Egypt occur as small granitic mass intruding the granodiorites. The monzogranites represent the central part of the mapped area and are intruded by the alkali-feldspar granites forming a small mass or cupola at the roof of the monzogranites. The alkali-feldspar granites cut by faults trending in NNW-SSE, E-W and NNE-SSW directions and show brecciation and local silicification, hematitization, sericitization and chloritization. Petrographically, the monzogranites are essentially composed of plagioclase, quartz, alkali-feldspars and biotite. The accessory minerals are apatite and zircon. The alkali-feldspar granites are mainly composed of K-feldspars, quartz, albite and biotite, while zircon, allanite, samarskite and violet fluorite are the accessory minerals. Chondrite-normalized REE patterns show that the alkali-feldspar granites have higher REE content (∑REE= 202ppm) than the monzogranites (∑REE= 43ppm). The monzogranites have small negative Eu anomaly reflecting high contents of plagioclase, while the alkali-feldspar granites show large negative Eu anomaly suggesting highly fractionated magma characterized by the least content of plagioclase. The chemical analyses of uranium and thorium indicate that the examined alkali-feldspar granites are characterized by higher U and Th contents (averages are 73 and 119 ppm, respectively) compared with the studied monzogranites (averages are 9 and 21 ppm, respectively). Detailed microscopic investigations supported by X-ray diffraction (XRD) and Environmental Scanning Electron Microscope (ESEM) with EDX microanalyzer for the radioactive alkali-feldspar granite samples revealed the presence of uranophane as secondary uranium mineral and thorite as thorium mineral beside some U-bearing accessory minerals such as samarskite, allanite, metamict zircon and violet f luorite.

Renewable energy attracts many researchers as the non-renewable one has negative environmental impacts and limited availability. One of the main types of renewable energy is the blue energy where electricity is generated by water waves using triboelectric nanogenerators (TENGs). Thin films play an important role in the performance and therefore the efficiency of TENGs as they represent the electrodes between which electrons move producing electricity. In order to increase the generated electricity from TENGs, the properties of these electrodes should be modified. Therefore, in this paper, nano- and micro-size thin films are fabricated and characterized by measuring the geometrical parameters and electrical properties. Thin films are fabricated using aluminum with thicknesses 0.5 μm and 1.5 μm on acrylic substrate and 0.5 μm copper film on different types of dielectric materials including PVC and polystyrene. Atomic force microscopy is used to measure the geometrical parameters of the fabricated films including thickness and surface roughness. Also, Gwyddion software is used for the grain size evaluation. On the other hand, Keithley is used for measuring the electrical properties including electrical conductivity and sheet resistance. It is found that the electrical conductivity of aluminum films is inversely proportional to the thickness. The corresponding measured values of the electrical conductivity of the fabricated thinner and thicker aluminum films equal 1.7 x 107 (Ω.m)-1 and 1.4×107 (Ω.m)-1, respectively. Whereas, the electrical conductivity of the fabricated copper film equals 8.8×107 (Ω.m)-1. In addition, the temperature effects on the electrical conductivity are studied. Finally, simulation of a TENG using COMSOL software is accomplished in order to evaluate the electrical outputs of potential, charge, and energy.