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Study on Properties of Silver Powder for Maki-e  [PDF]
Chieko Narita, Yutaro Shimode, Kazushi Yamada
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.61001
Abstract: Maki-e is a traditional Japanese decorative technique that uses the natural lacquer Urushi and metal powders. In 2014, there exist only two companies that manufacture silver powder for the purpose of Maki-e, and this study focuses on comparing the powders manufactured by them. Gloss and color of each silver powder were measured after Maki-e decoration was finished, and EDS (energy-dispersive X-ray spectroscopy) was used to determine the differences in their chemical composition. In addition, to verify the effect of polishing, residual gloss after sulfuration and polishing was measured. The study revealed that the shapes of the silver powders (Maru-fun, No. 1) manufactured by the two companies are different and it affects the occupancy rate of Urushi and powder, which in turn affects their gloss and color. Wakou silver has a very strong resistance to sulfuration; however, owing to its Pd content, its chroma is much lower than that of other powders. It was shown that sulfuration on powder surface can be removed by polishing irrespective of the shape and chemical composition ratio of the particles.
Effect of Different Eggshell Powder on Appearance of Eggshell Maki-e  [PDF]
Yutaro Shimode, Chieko Narita, Atsushi Endo, Kazushi Yamada
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.42016
Abstract:

The Maki-e technique with eggshell powder is one of techniques of Japanese traditional Urushi (Japanese lacquer) crafts. However, this technique is relatively new in the history of Maki-e, and there are no prior researches in terms of materials, structure, and properties. In this research, therefore we have aimed to evaluate the relationship between the eggshell powder sizes, dispersion, and color shade in Maki-e with eggshell powder. The difference between hen’s and quail’s eggshell characteristics and the effect of their powder particle size on appearance of eggshell Maki-e were discussed on the basis of the results of the particle size, circularity, particle number, and RGB value. As a result, it was found that the occupancy of the eggshell powder on the surface depends on not particle number but the particle size, whereas the whiteness of both eggshell powders depends on the particle size.

Advances in gold powder technology
Neville Collier
Gold Bulletin , 1977, DOI: 10.1007/BF03215432
Abstract: The routes for the preparation of gold powders, required for many important industrial applications, are described in this article. Attention is drawn to the highlights of recent work designed to improve the reproducibility of particle size and shape of gold powders made by precipitation from aqueous solutions.
Techniques used for the preparation and application of gold powder in ancient China
Zhao Huaizhi,Ning Yuantao
Gold Bulletin , 2000, DOI: 10.1007/BF03215486
Abstract: The preparation and application of gold powder have a long history in China. The ancient Chinese had a deep understanding of the morphology and size of naturally occurring gold powder. In the early stages, the technology for making gold powder probably involved grinding gold on a special stone. Later, the technique of making gold powder from gold foil was developed in the second century AD. The amalgamation technique was also invented in the 2nd century AD. In ancient China, gold powder was used for a number of applications, including in medicine and for paint and printing silk and paper etc. The techniques used for the application of gold powder in ancient China were the most advanced in the world at that time.
Gold alloys with shape-memory
G. B. Brook
Gold Bulletin , 1973, DOI: 10.1007/BF03215174
Abstract: Among a relatively few metallic systems certain alloys of gold exhibit a remarkable mechanical memory. After severe distortion a change of temperature will cause them to return to their original shape. This phenomenon is reviewed, and some possible applications are outlined for gold alloys having this unusual property in addition to their excellent resistance to corrosion.
The effect of the particle shape and structure on the flowability of electrolytic copper powder. I. Modeling of a representative powder particle
KONSTANTIN I. POPOV,SNEZANA B. KRSTIC,MILUTIN C. OBRADOVIC,MIOMIR G. PAVLOVIC
Journal of the Serbian Chemical Society , 2003,
Abstract: One of the most important properties of copper powder is its flowability which depends on the shape and the structure of the powder particles. A procedure for the determination of a representative powder particle permitting the free flow of copper powder is proposed.
Gold powder: Its preparation & application as described in ancient Sanskrit texts
R. K. Dube
Gold Bulletin , 1991, DOI: 10.1007/BF03214717
Abstract: Basically two techniques — mechanical comminution and chemical methods — were used in Indian antiquity for making gold powder. However, there were many variants of these techniques, which are described in detail below. It has been shown that two important applications of gold powder in ancient India were in medicine and for making colours for painting.
The effect of the particle shape and structure on the flowability of electrolytic copper powder. II. The experimental verification of the model of the representative powder particle
KONSTANTIN I. POPOV,MIOMIR G. PAVLOVIC,LJUBICA J. PAVLOVIC,MIOMIR G. PAVLOVIC
Journal of the Serbian Chemical Society , 2003,
Abstract: An analysis of the effects of the shape, surface structure and size distribution of particles on the flowability of the copper powder was performed. It is shown that the most important property of the particles of a powder, regarding the flowability of the powder, is the surface structure of the particles.
Shape Control of Silica Powder Formation  [PDF]
Marwa Nabil, Hussien A. Motaweh
Journal of Materials Science and Chemical Engineering (MSCE) , 2019, DOI: 10.4236/msce.2019.73004
Abstract: The purpose of the present research is the different morphologies production of crystalline and amorphous-silica powder. It’s a basic material for many pharmaceutical and environmental applications as well. And, it’s produced using the combination of the alkali chemical etching process and the ultra-sonication technique. The critical preparation conditions are KOH concentration (weight %) and the sonication time (hour). The paper presents the chemical mechanism of the silica particle formation as well as the different morphology. The results show the formation of crystalline and amorphous-porous-silica particles in the micrometer range with the porous order network that has pore sizes range in micrometer too. This synthetic uses commercial silicon, which could be useful for large-scale production. Also, the nano-sphere and nano-cubic shapes of silica powder are formed starting by commercial silicon powder.
Plasmonic Titania Photocatalysts Active under UV and Visible-Light Irradiation: Influence of Gold Amount, Size, and Shape  [PDF]
Ewa Kowalska,Sven Rau,Bunsho Ohtani
Journal of Nanotechnology , 2012, DOI: 10.1155/2012/361853
Abstract: Plasmonic titania photocatalysts were prepared by titania modification with gold by photodeposition. It was found that for smaller amount of deposited gold (≤0.1?wt%), anatase presence and large surface area were beneficial for efficient hydrogen evolution during methanol dehydrogenation. After testing twelve amounts of deposited gold on large rutile titania, the existence of three optima for 0.5, 2 and >6?wt% of gold was found during acetic acid degradation. Under visible light irradiation, in the case of small gold NPs deposited on fine anatase titania, the dependence of photoactivity on gold amount was parabolic, and large gold amount (2?wt%), observable as an intensively coloured powder, caused photoactivity decrease. While for large gold NPs deposited on large rutile titania, the dependence represented cascade increase, due to change of size and shape of deposited gold with its amount increase. It has been thought that spherical/hemispherical shape of gold NPs, in comparison with rod-like ones, is beneficial for higher level of photoactivity under visible light irradiation. For all tested systems and regardless of deposited amount of gold, each rutile Au/TiO2 photocatalyst of large gold and titania NPs exhibited much higher photoactivity than anatase Au/TiO2 of small gold and titania NPs. 1. Introduction Titanium(IV) oxide (titania) is one of the most commonly studied semiconductors due to its high photocatalytic activity, redox properties, thermal and chemical stability, and nontoxicity [1–3]. The limitation in its application, resulting from low quantum yield (fast recombination of charge carriers: e?/h+) and necessity to use UV irradiation, may be overcome since modified titania powders often possess higher level of activity and ability of working under visible-light irradiation. A huge variety of organic [4–7] and inorganic compounds [8–10] have been examined as dopants or surface modifiers. Among them, noble-metals particles have attracted attention, since they may enhance the transfer of photogenerated electrons prolonging charge carriers lifetime [11–16]. Some of them, exhibiting plasmonic properties, such as gold and silver, may also activate wide band gap semiconductors, titania or ceria, towards visible light [17–20]. Since Haruta’s pioneering studies on catalytic (dark) properties of gold nanoparticles (NPs), a lot of studies have been carried out to explain nature of catalytic reaction and to find optimal conditions for efficient oxidation of organics [21, 22]. Regarding catalytic and plasmonic properties of gold NPs the novel area of
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