著者

高橋 明宏 山元 直行 豊廣 利信

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.15, no.1, pp.38-44, 2015-04-13 (Released:2015-04-13)

参考文献数

21

---

The Shielded metal arc welding is mostly popular for fused injection method of metal to metal. The spatter particle of various sizes appears during the metal arc welding, and then adheres so strongly on the surface of welded plate. In general, the commercial spatter adhesion preventive agent is coated on the surface of plate before welding. However, the agent from artificial organic synthesis has several problem, such as influence of global environmental and human health, stink and expensive. The purpose of this study is to develop the new welding spatter adhesion preventive agent made of water, flour powder and honey, which brings the environmental merit, no stink and low cost. Effective contents among water, flour and honey was confirmed by sensory evaluation test and experimental observation after welding. The results of tensile inspection test of a butt welded specimen of SS400 and hydrogen analysis by JIS Z3118 satisfied welded strength and the reliability of welding. Anti-adhesive mechanism was discussed based on heat characteristics and observation of boundary between spatter and surface of welded plate. Another combinations as grain or starch powder and syrup with spatter anti-adhesive effect were also described.

著者

永津 慶伍 吉岡 修哉

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.19, no.2, pp.137-144, 2019-07-24 (Released:2019-08-01)

参考文献数

9

---

Flow structure in human bronchus is experimentally investigated. Resin bronchus model that is made by 3D printer is provided for the experiment. Velocity distributions are measured by PIV. Microbubble is used as tracer particle of the PIV measurement. Refractive index matching technique are applied to measure velocity in the bronchus model. To simulate non-uniform inlet flow from larynx including Dean vortices, a bent pipe is connected upstream of the bronchus model. Dean number was changed by the radius of curvature of the bent pipe. Due to this inlet condition, velocity distribution in the bronchus model shows distorted top-hat profile. In branch region and curved region of the bronchus model, velocity distributions that indicate adverse pressure gradient condition are confirmed. Separated flows are also confirmed in those region. Dean vortices induced from upstream bent pipe uniformize velocity distribution in the bronchus model. Strong Dean vortices may restrict flow separation in the adverse pressure gradient region. This trend is remarkably observed in higher Dean number condition.

著者

相澤 孝司 菅野 昭

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.13, no.1, pp.67-73, 2013-03-28 (Released:2013-09-28)

参考文献数

12

---

The main role of conventional safety helmets is to protect the human head from external forces. So far the design of standardized helmets has placed an excessive emphasis on mechanical performance from this standpoint. During wearing the helmets, users experience high temperature rise in the head as well as excessive perspiration and an oppressive feeling. These discomforts prevent users from wearing the helmets. Behavior of air flow around the helmets needs to be studied in order to examine air cooling effects while users wear the helmets. Several techniques such as smoke wire, tuft and smoke injection methods have been applied to visualize air flows around the helmets which a mannequin wears in a low-velocity type wind tunnel. The pressure distributions on the outer surfaces of the helmets are measured on pressure transducers using diffusion type semiconductors. The stream lines and pressure distributions on the outer surfaces of the helmets are clarified by the present experiments. It is expected that the helmets are designed more rationally based on both fluid mechanics and the present experimental data.

著者

石井 慶子 麓 耕二

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.18, no.3, pp.163-168, 2018-10-11 (Released:2018-10-12)

参考文献数

8

---

The mechanism of Pulsating Heat Pipe (PHP) is still unclear because of its complex thermal fluid property. There are few researches that measured the temperature distribution inside the PHP. This study executed the visualization of temperature distribution inside a PHP. Temperature sensitive paint was painted on the optical window. The TSP was excited by UV LED light and the luminescence intensity was captured by CMOS camera. The fluid and wall temperature inside the PHP was measured instantaneously. We captured a thermal flow induced by the evaporation and oscillation. The measurement accuracy was 0.2 ° C. We measured the temperature of working fluid adhering to the wall surface that was colder than the ambient temperature. When the flow was oscillating, the temperature at an arbitrary point inside the channel was fluctuated. On the other hand, when the low was circulating, the temperature at the channel became stable apparently. Acquired data was qualitatively in agreement with known PHP properties. Temperature measurement by TSP is considered to be effective for PHP performance evaluation and flow mechanism investigation.

著者

大 久 保 努 高 橋 優 信 久 保 田 健 吾 原 田 秀 樹 時 田 政 輝 上 村 繁 樹 前 野 一 夫

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.15, no.1, pp.30-37, 2015

---

Down-flow hanging sponge (DHS) reactor has been developed mainly for sewage treatment in developing countries. The novel rector employs polyurethane sponge material as support media, which promises a proliferation of a large amount of biomass, and thus an excellent capability of removing pollutants. The characterization of the three types of sponge support media is conducted in respect of water flow and oxygen uptake ability. Water was supplied to the device which consisted of 40 sponge media connected in series, and then tracer experiment was carried out. The ratios of actual hydraulic retention time (HRT) per theoretical HRT were in the range of 25-67% depending on the type of support media, meaning that short circuit flow occurs in this type of reactor. By supplying deoxygenized water from the top of the device, overall volumetric oxygen transfer coefficient, K_La, was evaluated. In spite of the non-aerated conditions, the K_La values were so high, 0.56-4.88 (1/min), surpassing those of other mechanically aerated aerobic processes. Furthermore, it was found that the suspended solids (SS) concentration in the influent played a role to increase the ratio of actual HRT/theoretical HRT, meaning that management of the influent SS concentration is prerequisite for preventing the clogging problem in the DHS.

著者

藤川 正毅 三上 貴央 小林 卓哉 隆 雅久

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.7, no.4, pp.387-392, 2007 (Released:2008-06-25)

参考文献数

12

---

The authors have developed a new automatic technique of drawing the master curve from the experimental data measured by the Dynamic Measurement Tester. In this paper, the experimental conditions recommended by Japanese Industrial Standards are considered and modified from the perspective of drawing the master curve. To verify the effectiveness of the proposed technique and the experimental conditions, the storage and loss moduli of epoxy resins and rubber materials are measured, and the proposed technique is applied to the experimental data. From the results, it is confirmed that the master curves are obtained automatically and expeditiously.

著者

西原 小百合 西原 一嘉 井口 学

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.10, no.2, pp.217-223, 2010-06-25 (Released:2010-12-25)

参考文献数

5

---

Recently, design of cars and household appliances has mainly been carried out using various types of 3-D CAD systems. Although the 3-D CAD is superior for presenting the shape of the object, some problems are left unsolved. For example, it is widely recognized in the mechanical design field that conversion of a 3-D image to 2-D production drawings is not always adequate because the description of the measure is sometimes inaccurate. Under these conditions, correction of the drawings should be carried out one by one. Nevertheless, the use of 3-D CAD is rapidly increasing and, accordingly, educational institutions teaching 3-D CAD are increasing year by year. This paper reports on the introduction of 3-D CAD to descriptive geometry field. The objective of the present study is to improve the above-mentioned shortcoming of 3-D CAD on the measure description. Many kinds of problems encountered in descriptive geometry are solved using 3-D CAD.