著者
向阪 保雄 野村 俊之 内藤 牧男
出版者
一般社団法人 粉体工学会
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.57, no.10, pp.526-529, 2020-10-10 (Released:2020-12-09)
参考文献数
5
被引用文献数
2

Aerosol infection issues by COVID-19 were discussed from the viewpoint of particle technology, and the following conclusions were obtained: 1) Number of virus contained in a 10 μm droplet is very few, only 1 virus per 2000 droplets, whereas 0.5 virus in a 100 μm droplet, if 106 copies/mL of viral load in saliva is assumed. 2) Droplets larger than 100 μm can quickly settle down by gravity. 3) The possibility of aerosol infection is very low unless in unusual environments. 4) Mask is very effective, but the leakage from the space between mask and face has risk in heavy exhalation.
著者
鈴木 道也
出版者
一般社団法人 粉体工学会
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.21, no.2, pp.103-109, 1984-02-10 (Released:2010-04-30)
参考文献数
17
著者
奥平 有三 安藤 秀行 佐藤 宗武 宮南 啓
出版者
The Society of Powder Technology, Japan
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.32, no.5, pp.311-318, 1995-05-10 (Released:2010-04-30)
参考文献数
16
被引用文献数
1 2

The sound absorption coefficients and sound velocity of various powder beds were measured in the frequency range of 200Hz to 2kHz. The powder beds were comprised of classified powders having mean particle diameters from 53 to 300μm. For the powder beds consisting of smaller particles, the sound absorption coefficients showed distinct peaks due to the excitation of normal vibration modes of the powder bed. In the frequency range in which sound absorption peaks appear, the sound velocity has almost on frequency dependency, and sound energy is dissipated mainly by the interaction of vibrated particles. As particles with larger diameters were used, these peaks decreased in amplitude, but the level of sound absorption increased in the high frequency range. In this frequency range, sound velocity increases according to frequency, and sound energy is dissipated mostly by the viscosity of the air in the pores.
著者
高井(山下) 千加 馬渕 裕也 池田 純子 藤 正督 仙名 保 大矢 豊
出版者
一般社団法人 粉体工学会
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.58, no.4, pp.164-169, 2021-04-10 (Released:2021-05-21)
参考文献数
16
被引用文献数
1 1

Mechanochemistry offers sustainable synthesis of the functionalized cellulose nanofiber (CNF). In this study, changes in the microstructure of the CNF aqueous sol by planetary ball milling were investigated in terms of its rheological behavior, crystallinity, and diameter distribution. The surface activity of the CNF was additionally characterized by a pulsed nuclear magnetic resonance (NMR). A decreased thixotropy hysteresis loop observed in the 100 min−1-treated CNFs indicated a weaker interaction among the fibers, but still having a three-dimensional structure. 300 min−1 could collapse them. A decreased x-ray diffraction peak intensity observed in the 500-min−1-treated CNF could indicate a split in the fiber’s bundle as well as shredding. An increase in the wet surface area (SNMR) could indicate surface activity in the 500-min−1 milled CNF sol. Such newly formed hydroxyl groups can serve as effective reaction sites with, for example, the TiO2 precursor and perhaps favorably works to improve the photocatalytic performance.
著者
神田 良照 山下 隆司 佐々木 寿人 新井山 忍
出版者
一般社団法人 粉体工学会
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.24, no.10, pp.635-639, 1987
被引用文献数
1

In order to study the relationship between grindability and particle shape, eight kinds of particle sizes and the seven kinds of shape indices of feed particles and unfractured particles were measured after impact crushing. The samples used were quartz and limestone. The size of particles ranged from 4 to 6 meshes.<br>As a result, the shape indices defined by (N/T), (L/T) and (F/T) are useful to characterize the grindability of particles.

2 0 0 0 OA 巨大砂時計

著者
志波 靖麿
出版者
The Society of Powder Technology, Japan
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.28, no.11, pp.694-701, 1991-11-10 (Released:2010-04-30)
参考文献数
3
著者
鈴木 健吾 中野 良平 山口 日出樹 丸田 彩子 中野 長久
出版者
The Society of Powder Technology, Japan
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.50, no.10, pp.728-732, 2013-10-10 (Released:2013-10-18)
参考文献数
8
被引用文献数
3

There is a higher demand for naturally derived organic fillers than for conventional inorganic fillers, which have a greater environmental impact. For example, cellulose is commonly available organic filler ; however its dispersion in the matrix such as polymers may be poor depending on the base material, and it cannot even form a complex. In this study, we focused on paramylon, which is a naturally derived polysaccharide having unique physical properties. Using a universal testing machine EZ Graph-10 kN, we compared the physical properties of a compound containing 100 polypropylene, 20 paramylon, and 5 maleic-acid-modified low-molecular-weight polypropylene resin as a compatibilizer, with a filler-free compound of the same formulation It was found that with increasing paramylon, the maximum point stress and elasticity increased, while the maximum point displacement decreased. This result suggests that paramylon is a novel prospective filler material.
著者
藤尾 雄策 川合 良岳
出版者
粉体工学会
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.26, no.1, pp.27-32, 1989-01-10 (Released:2010-04-30)
参考文献数
14

The angles of repose of nonglutinous and glutinous rice as typical biological particles were measured by the revolving cylinder test under variable ambiences ranging from air to water.The results were as follows:1) Almost the same angle of repose of glass beads resulted under the ambience in air and in water. When comparing the angle of repose of rice under ambience in water with that in air, angles of repose of 8 and 10 degrees were given for nonglutinous rice and for glutinous rice, respectively. for glutinous rice, respectively.2) As the amount of water was increased, defined as the total kg of water per 100kg of dried rice particles, the angle of repose of rice suddenly increased at 30 to kg of water. When the amount of water was 50 to 150×10-3kg, the angle of repose could not be determined because of strong cohesive force among the particles.3) Both the increase in the bulk volume and the decrease of the apparent density of rice caused by an increase of granule size since the adsorption of water had little on the measures of the angle of repose.4) A strong minus correlation existed between the apparent density and the angle of repose in water up until water was noticed on the surface of the rice granules.
著者
豊田 直晃 浅野 浩志 北原 路郎 中田 悟 浅井 厳 高尾 泰正 島田 泰拓 羽多野 重信
出版者
粉体工学会
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.52, no.12, pp.694-700, 2015-12-10 (Released:2015-12-26)
参考文献数
17
被引用文献数
3

The texture of powder cosmetics, such as "smoothness" and "moist feeling", is one of the most important properties for the usability assessment. In general, we rely upon the sensory evaluation for cosmetics. However, such subjective evaluation tends to be vague because of not only the lack of evaluators' skill but also the reproducibility error on environmental factors. Therefore, a highly-reliable evaluation method by using physical properties, such as particulate mechanical characteristics, is desired. In this study, we investigated the correlation between the sense of use and physical properties by the direct shear testing of the powder bed for five kinds of cosmetic powder. As a result, we found that internal friction coefficient μi was correlated with the "smoothness". Furthermore, the shearing cohesion τc and the degree of PYL (Powder Yield Locus) curve were related to "moist feeling", respectively.
著者
峯尾 隼人 正岡 功士
出版者
一般社団法人 粉体工学会
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.54, no.9, pp.596-603, 2017-09-10 (Released:2017-10-31)
参考文献数
5
被引用文献数
1 1

We examined about the chemical change of Japanese sea salt using Thermo Gravimetric and Mass Spectrometric analyzer (TG-MS). TG-MS spectrums of the salt, calcium chloride tetra-hydrate and magnesium chloride hexa-hydrate were measured. From the result, it’s thought that a formation of hydrogen chloride by heating the salt is caused by the chemical decomposition of magnesium chloride hydrate in general. On a temperature rising process, practical reaction temperature is increased with sample mass and heating rate. And the formation rate of the hydroxyl magnesium chloride and magnesium oxide is increased by moisture in a gas phase. The moisture in a gas phase cause oxidize anhydrous magnesium chloride to magnesium oxide around 500°C as shown in following reaction. MgCl2+H2O→MgO+2HCl. From these result, we concluded that control of residence time, gas-solid volume ratio and moisture in gas phase is important for reduce of hydrogen chloride formation in drying process and calcining process.
著者
山井 三亀夫 中田 洋一
出版者
一般社団法人 粉体工学会
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.55, no.2, pp.95-103, 2018-02-10 (Released:2018-03-20)
参考文献数
9
被引用文献数
2 1

It is well known that Discrete Element Method, DEM, has been applied to predict dynamics of granular systems by tracing all the particles by solving equations of motions. When it is applied to industrial applications, we immediately are faced to the problems of computing cost, due to too many particles. That is why coarse-grained (CG) simulation methods are required, where a group of particles is replaced as a coarse-grained particle to decrease the number of particle. So far, several CG simulation methods such as SPA model and coarse-grained model have been discussed. So far, CG simulation method has problems of reproducing scaling properties of the granular systems at high scaling ratios, in which contact effects are dominant. The aim of this research is to solve the problems. This paper proposes a new simulation method called scalable DEM (SDEM), which is based on the followings assumptions: 1) particles on the force network only contributes to the dynamics of granules, 2) there are statistically same picture in terms of structure for different scaling ratios. In the paper, SDEM was applied to two systems: “dam break” and “discharge of granules from a rectangular container.” The following results were obtained through the research: a) comparable results were obtained for different scaling ratios, b) simulation predictions match to the experimental data for both two cases.
著者
酒井 幹夫 山田 祥徳 茂渡 悠介
出版者
The Society of Powder Technology, Japan
雑誌
粉体工学会誌 (ISSN:03866157)
巻号頁・発行日
vol.47, no.8, pp.522-530, 2010-08-10 (Released:2010-08-25)
参考文献数
23
被引用文献数
5 5

The Discrete Element Method (DEM) is widely used in computational granular dynamics. The DEM is a Lagrangian approach where individual particle is calculated based on the Newton's second law of motion. Hence, the DEM enables us to investigate the granular flow characteristics at the particle level. On the other hand, the DEM has a difficulty to be used in large-scale powder systems because the calculation cost becomes too expensive when the number of particles is huge. Consequently, we have developed a coarse grain modeling as a large scale model of the DEM. The coarse grain particle represents a group of original particles. The coarse grain model was applied in typical gas-solid and solid-liquid two phase flows. The cohesive force like the van der Waals force was not considered in these simulations. In the present study, the coarse grain model is evolved to simulate the cohesive particles by considering the interparticle van der Waals force. The adequacy of the coarse grain model is proved by comparing the simulation results of original particle system. It is shown that the coarse grain model considering the interparticle force can simulate the original particle behavior precisely.