著者

伊良皆 啓治 N. Chaiyapoj 中西 徳昌 後藤 恵一 上野 照剛 小田原 成計 中山 哲 茅根 一夫 山崎 慶太

出版者

公益社団法人 日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:02850192)

巻号頁・発行日

vol.21, no.4_2, pp.805-808, 1997 (Released:2007-08-20)

参考文献数

7

被引用文献数

1 1

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We have developed a multi-channel high-resolution SQUID magnetometer. This system consists of 12-channel pick-up coils 5 mm in diameter located on a 7.5 mm grid. The base-line of the gradiometer is 15 mm. The distance between the pick-up coil and the outside surface of the dewar is 5 mm. We measured the magnetic field produced by the activity of the orbicular muscle of eye, the magnetocardiogram produced by a human, and the magnetocardiogram produced by a rat. It is possible to obtain signals with good spatial resolution.

著者

山崎 慶太 桒原 浩平 染谷 俊介 濱田 靖弘 小林 宏一郎

出版者

日本建築学会

雑誌

日本建築学会環境系論文集 (ISSN:13480685)

巻号頁・発行日

vol.85, no.771, pp.351-360, 2020 (Released:2020-05-30)

参考文献数

20

被引用文献数

1 1

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To obtain basic data for prevention of heat stroke during construction work in a hot environment, we analyzed the effects of wearing ventilated work wear (VWW) and water intake (RWI). First, experiments were carried out with nine male form workers in an artificial climate chamber (AC) at 34°C. Second, measurements were carried out with four male form workers and one male rebar placer at an outside construction site (CS) for four days in August 2017. It was carried out from 8:00 to 17:00 and was divided into four shifts split up by breaks as follows: 8:00 to 10:00, 10:30 to 12:00, 13:00 to 15:00; and 15:30 to 17:00. Activity amount (ACT) was continuously measured. WBGT was measured in the CS. The sweat rate (SR), the rate of naked body weight loss (RBWL, only in the AC), body weight loss while fully clothed (RBWLC), and RWI were each measured and calculated as the difference between the values before and after work per unit time. Evaporation rate (ER) was defined as the sum of RBWLC and RWI. SR in the CS was estimated from the ER by using the regression equation between ER and SR in the AC data. In the AC experiment, the SR during work was constant and RBWL was negatively correlated with RWI, those were statistically significant, regardless of whether the workers wore VWW. The RWI and SR of workers not wearing VWW were significantly higher than those of workers wearing VWW. RWI increased significantly and RBWL decreased as ACT increased. This is the reason that RBWL was negatively correlated with the RWI in the AC. In the CS experiments, the SR of workers not wearing VWW increased significantly as WBGT increased, but the RWI did not change significantly; as a result, RBWL increased significantly with WBGT. The SR of individuals wearing VWW, which was lower than that of those not wearing VWW, remained almost constant with increasing WBGT, whereas RWI did not increase with WBGT. As expected from these results, RBWL remained constant as WBGT increased and was consistently lower than that of workers not wearing VWW. The ER of works in the CS was significantly higher than that of those in the AC due to the difference between the averaged ACT in the AC (1.8 Mets) and CS (2.4 Mets). In the CS experiments, we estimated the dewatering ratio (DR) by body weight loss while fully clothed (BWLC), since BWL was not measured. The fluctuation during working shifts of BWLC and DR of workers was compared between those wearing and those not wearing VWW on hot two days. In the shifts, the BWLC of workers not wearing VWW was significantly higher than that of those wearing VWW. Furthermore, in the breaks between shifts, the amount of water recovered by workers not wearing VWW was significantly lower than that of those wearing VWW. As a result, after the last shift, the average DR (2.03) of workers not wearing VWW was higher than that of those wearing VWW (1.53). We supposed there is a limit to the amount of water that workers in a construction site can drink. Thus, we verified that, in the CS setting, RBWL increased with increasing WBGT mainly due to insufficient RWI, but could be partly decreased by using VWW, which decreased the SR.

著者

山崎 慶太 奥田 清明 阿部 隆之 内川 義則 志村 徹 小谷 誠

出版者

公益社団法人 日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:02850192)

巻号頁・発行日

vol.16, no.6, pp.769-774, 1992-12-01 (Released:2013-01-11)

参考文献数

7

被引用文献数

6 7

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This paper describes the design and the development of a prefabricated magnetically-shielded-room (PMSR) of the hexagonal type for high sensitive measurement of neuro-magnetic fields such as magnetoencephalography (MEG) mainly using SQUIDs with first and/or second-order gradiometers. This PMSR consists of prefabricated plywood panels 1.2 m wide×2.4 m high×24 mm thick. It covers a floor area of about 9 m2. The panel is sandwiched by two layers of high-μ metal sheets 1 mm thick. The shielding factor at the center of PMSR against the external magnetic field is 20 to 40 dB in the range of DC to 120 Hz. Magnetic noise inside PMSR measured by a second-order gradiometer was less than hundreds fT above 0.5 Hz excepting 50 Hz. In this case, a second order gradiometer was able to eliminate the common mode magnetic noise of about 20 Hz, which was essentially observed by a magnetometer, caused by the vibration of PMSR. These results were discussed and compared with the calculations.