117 research outputs found

    An Overview on the Possibility of Scandium and REE Occurrence in Sulawesi, Indonesia

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    The development in modern-high technology application is growing rapidly, resulting in the constant supply of critical metal and rare earth elements (REE). Currently, resources of these elements are restricted and new source of these elements need to be discovered accordingly. Scandium (Sc) as one of critical metals is an important metal for electrolyte of solid oxide fuel cells and other advance technology. In addition, REE are the important elements in the use of permanent magnets and rechargeable batteries. This manuscript reports an overview on the possibility of scandium and rare earth element occurrences in Sulawesi. Sc is concentrated in limonite layers in Soroako ultramafic rocks as a result of Fe3+ site substitution of mafic minerals (pyroxene, amphibole, etc.) during a laterization process. REE are enriched in association with clay minerals in B horizon from heavily weathered granitic rocks in Palu and Masamba, suggesting the possibility of ion-adsorption style mineralization. The lateritic soil of the ultramafic rocks and the weathered crusts of the granitic rocks in Sulawesi could be the potential sources of scandium and rare earth elements, respectively

    Fine Particles of Ti and Ti-Mo Alloy Prepared by Gas Evaporation

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    Fine particles of Ti-Mo alloy were prepared by evaporation. When Ti-40at % Mo alloy was evaporated on tungsten filament, fine particles of Ti contaminated with W were obtained. These particles were polyhedron in shape and 10~250nm in diameter. Average diameter and size distribution increased with pressure of argon gas (100~600 Torr). When pure Ti was placed on the Mo filament and evaporated from melt down of heated Mo filament in helium gas, fine particles of pure Ti and of Ti-Mo alloy were obtained. In this case, Ti particles were of indeterminate form and of several tens nm in diameter, and their diffraction pattern was of common α-Ti. On the other hand, composition of the Ti-Mo particles was determined to be 18at % Mo by an analysis of EDX. Structure of Ti-Mo particles could not be determined because their diameters were more than 600nm. The temperature of Mo filament, for the most part, was about 1800℃, and there pure Ti particles were produced. The temperature of the fused part of the filament was locally higher than 2600℃, and there Ti-Mo particles were produced. Fine structures of contact region among some Ti particles were observed with HRTEM

    Possible high TcT_c superconductivity in La3_3Ni2_2O7_7 under high pressure through manifestation of a nearly-half-filled bilayer Hubbard model

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    Inspired by a recent experiment showing that La3_3Ni2_2O7_7 exhibits high TcT_c superconductivity under high pressure, we theoretically revisit the possibility of superconductivity in this material. We find that superconductivity can take place which is essentially similar to that of the bilayer Hubbard model consisting of the Ni 3d3z2r23d_{3z^2-r^2} orbitals. Although the coupling with the 3dx2y23d_{x^2-y^2} orbitals degrades superconductivity, TcT_c can still be high enough to understand the experiment thanks to the very high TcT_c reached in the bilayer Hubbard model.Comment: 3 figures, 5 page

    BASIC EXPERIMENTS OF CS UPTAKE CAPABILITY FOR Eleocharis acicularis

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    Soil in the Fukushima area has been polluted with the radioactive contaminants such as Cs by the accident of Fukushima Daiichi nuclear power plant in March 2011. Remediation of soil contaminated with radioactive Cs remains one of the most important problems. Phytoremediation is an environmental remediation technique that takes advantage of plant physiology and metabolism to remove radioactive contaminants. Eleocharis acicularis is well known as heavy metal hyperaccumulator aquatic plant and expected as the strong candidate for application to Phytoremediation of polluted water and soil. In this study, a laboratory experiment was carried out to investigate the potential of E.acicularis for Phytoremediation of radioactive Cs contaminated site.The plants were grown hydroponically and placed in solutions containing Cs and K at different concentration (Cs concentration: 5 mg/L, K concentration: 0, 0.2, 2, 5, 50, 100 mg/L) in a period of 21days.In the experimental results, the highest concentration of Cs was 1560 mg/kg-DW in E. acicularis after 21 days. The concentration of Cs in plants decreased with the increasing initial concentration of K in the solution. This results indicate that E. acicularis has the ability to accumulate radioactive Cs from radioactive Cs contaminated soil and water, making it a good candidate species for radioactive Cs Phytoremediation. Keywords : Fukushima, Eleocharis acicularis, phytoremediation, C

    Threats to Food Safety and Sustainability of Nike (Awaous melanocephalus) in Gorontalo Province

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    The objective of this research is to develop the industrial-scale fluid bed dryer for paddy by scale-up of lab-scale experimental data. The developed dryer was conducted by simulation using a two phase model. Firstly, the experimental works by using lab-scale batch fluid bed dryer, was conducted to determine the drying curve of paddy (Xin 0.32 kg/kg dry base). In the experimental works, the inlet air temperature was varied (°C): 40; 50; 60. The drying rate curves as a function of moisture content showed only decreasing drying rate period. Then, a very good agreement between the measured and simualtion results of the profile of moisture content in solids was produced by simulator. Finally, a simulated continuous fluidized bed dryer for paddy with dimension 5 m of length and 1.5 of width was succesfully performed, in which the influence of mass solid flow rate 0.1; 0.2; 0.4 tons/h, height of bed 0.25; 0.50; 0.75 m, and air temperature 50; 70; 100 °C on drying process were studied. Keywords: Paddy, fluid bed dryer, batch, contonious, modelling, simulatio

    MECHANICAL PROPERTIES OF SUGAR PALM (ARENGA PINNATA) ROPES AND NETS FOR AGRICULTURAL PURPOSES

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    Sample of Arenga Pinnata (AP) fibres, ropes and nets were prepared from AP ropes using traditional tools. The ropes and nets were used as agricultural material such as vertical farming of vines (passion fruit, grape, bitter gourd, and melon) in Gorontalo and Japan. The combination of nets and vines acts as green curtain (GC) which. Could mitigate the thermal energy in outdoor as well as indoor buildings. and tested with the deformation rate of up to the point of rupture. To avoid the failure of ropes and nets on supporting the weight of the vines, the Universal Testing Machine Model WDW-50 were used to determine the ultimate tensile forces. While the physical size of the AP fibres, ropes and nets also being measured to confirm the uniformity of the individual ropes and net

    Application of the Green Curtain Concept Using Passion Fruit (Passiflora edulis) as an Energy Efficiency Solution for Residential Houses

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    The application of green curtains is one of the important things for thermal comfort and energy efficiency. This research was conducted from April to September 2022, aiming to measure differences in temperature and humidity in rooms with green curtain and without green curtain and to find out the response of occupants in room with green curtains. In this study the plant used was the passion fruit vine, because this plant is one of the many fruits that grow in tropical and sub-tropical regions. The vine medium uses aluminium wire with a diameter of 3 mm, a width of 90 cm x 1 meter long, the distance between the wires is 15 cm x 15 cm. in April there was no difference in temperature between the two rooms, with an area of 133cm2 while in September, the room temperature with the green curtain was lower than in rooms without green curtain with a difference of 1.8 ºC. In this study the application of green curtain is very significant as a solution to thermal comfort

    Examining Preference Heterogeneity in Best-Worst Scaling: Case of Preferences for Job Opportunities in Artisanal Small-Scale Gold Mining (ASGM) Communities in Indonesia

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    This research empirically examines the preferences for job-related attributes among rural villagers living close to artisanal and small-scale gold mining (ASGM) in Indonesia. Based on hypothetical scenarios in which a private company collaborates with the local government to establish a food processing industry in these villages, a questionnaire survey designed with best–worst scaling (BWS) was administered to households to determine their preferences. Additionally, the heterogeneity among the villagers was examined by applying a latent class logit (LCL) model. The main household survey was conducted in 2019 in Bone Bolango Regency, Gorontalo Province. The estimation results revealed that villagers are separated into four classes, and each class has different and unique preferences. Creating more job opportunities for society is a highly evaluated attribute; however, the preference for skill acquisition differs among groups. The results indicate that accounting for heterogeneous preferences regarding job opportunities is helpful to delink dependency on ASGM and health hazards and improve the livelihoods of rural villagers. The study yields key information to substantially reduce environmental and health hazards in the poverty-plagued ASGM community by facilitating job opportunities in Indonesia

    “Transmantle sign”を示す限局性皮質異形成における神経細胞の成熟と分化の未熟性:層特異的マーカー発現による解析

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    Transmantle dysplasia is a rare type of focal cortical dysplasia (FCD) characterized by expansion of the cortex from the deep white matter to the surface and in which there is a FCD IIA or IIB pathologic pattern. To characterize possible mechanisms underlying this regional disorder of radial migrating cells, we studied the expression patterns of neocortical layer-specific markers using immunohistochemistry in surgical specimens from 5 FCD IIA and 4 FCD IIB cases in children. All neuronal cells expressed the mature neuron marker MAP2/2B but not the microglia markers Iba-1 and CD68. Some layer-specific markers showed distinct expression patterns. TBR1-positive, SATB2-positive, and FOXP1-positive cells were diffusely distributed in the cortex and/or the white matter. TBR1-positive and FOXP1-positive cells were generally more numerous in FCD IIB than in FCD IIA and were mostly in the cortical molecular and upper layers. FOXP1-, FOXP2-, and CUTL1-positive cells also expressed the immature neuron marker, Nestin/PROX1, whereas TBR1-, CTIP2-, and SATB2-positive cells only expressed MAP2/2B. These data highlight differences between FCD IIB and FCD IIA with more cells having the immature marker in upper layer markers in the former. By analyzing layer-specific marker expression patterns, we identified apparent neuronal maturation differences between FCD IIA and FCD IIB in cases of transmantle dysplasia.博士(医学)・乙第1312号・平成25年5月29
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