On the Steering Labor of Tractor Operator(I) : Steering force during transport and field operation

1.トラクタのアスファルト路面走行および畑地ロータリ耕における操舵力の特性を知るため,トラクタの前輪荷重,作業速度およびオペレータの諸条件をかえ,作業中のトラクタの横変位,実舵角,操舵角および操舵力を測定した. 2.ハンドルにかかる力とその累積頻度数との間には曲線的関係があり,ハンドルにかかる小さい力の頻度は一般に多い. 前輪荷重を軽くした場合,ハンドル操舵の走行では逆にハンドルにかかる力が小さく,累積頻度数は多くなる. また,作業速度,オペレータによって影響をうける. ロータリ耕においてはアスファルト路走行に比してハンドルにかかる力および累積頻度は増加し,3倍近くになる. 3.ハンドルにかかる力とハンドル回転角速度から求めた操舵馬力と相対頻度との間には双曲線的関係があり,操舵馬力の大きいときの路面走行の場合と比して6倍近い. 4.単位時間当りの操舵に要する仕事量はトラクタの前輪荷重が軽いとき,作業速度が低いときに少なくなる. 作業速度が変動しても単位時間当りの操舵に要する仕事量は同じ程度となる. ロータリ耕での単位耕うん距離当りの仕事量は走行時のそれと比して30～40倍近い

The 3-D kinematics of water masers around the semiregular variable RT Virginis

We report observations of water masers around the semiregular variable RT Virginis (RT Vir), which have been made with the Very Long Baseline Array (VLBA) of the National Radio Astronomy Observatory (NRAO) at five epochs, each separated by three weeks of time. We detected about 60 maser features at each epoch. Overall, 61 features, detected at least twice, were tracked by their radial velocities and proper motions. The 3-D maser kinematics exhibited a circumstellar envelope that is expanding roughly spherically with a velocity of about 8 km/s. Asymmetries in both the spatial and velocity distributions of the maser features were found in the envelope, but less significant than that found in other semiregular variables. Systematic radial-velocity drifts of individual maser features were found with amplitudes of <= 2 km/s/yr. For one maser feature, we found a quadratic position shift with time along a straight line on the sky. This apparent motion indicates an acceleration with an amplitude of 33 km/s/yr, implying the passage of a shock wave driven by the stellar pulsation of RT Vir. The acceleration motion is likely seen only on the sky plane because of a large velocity gradient formed in the accelerating maser region. We estimated the distance to RT Vir to be about 220 pc on the basis of both the statistical parallax and model-fitting methods for the maser kinematics.Comment: 18 pages, 8 figures. Accepted to appear in the Astrophysical Journa

Recent Results from LHD Experiment with Emphasis on Relation to Theory from Experimentalist’s View

he Large Helical Device (LHD) has been extending an operational regime of net-current free plasmas towardsthe fusion relevant condition with taking advantage of a net current-free heliotron concept and employing a superconducting coil system. Heating capability has exceeded 10 MW and the central ion and electron temperatureshave reached 7 and 10 keV, respectively. The maximum value of β and pulse length have been extended to 3.2% and 150 s, respectively. Many encouraging physical findings have been obtained. Topics from recent experiments, which should be emphasized from the aspect of theoretical approaches, are reviewed. Those are (1) Prominent features in the inward shifted configuration, i.e., mitigation of an ideal interchange mode in the configuration with magnetic hill, and confinement improvement due to suppression of both anomalous and neoclassical transport, (2) Demonstration ofbifurcation of radial electric field and associated formation of an internal transport barrier, and (3) Dynamics of magnetic islands and clarification of the role of separatrix

日本睡眠歯科学会口腔内装置診療ガイドライン作成委員会の活動報告

Oral appliance therapy was approved by national health insurance in Japan in 2004 and oral appliances（OAs）have since been widely used in the treatment of obstructive sleep apnea（OSA）. We herein described the process of making clinical practice guidelines by the task force of the Japanese Academy of Dental Sleep Medicine as a work report. In Japan, OAs are covered by national health insurance. In consideration of the balance between medical treatment fees and the price of technical materials, we used a single-piece（monoblock）OA that advanced the mandible forward and limited mouth opening in OSA patients in Japan. The Japanese Academy of Dental Sleep Medicine（JADSM）focused on OAs frequently used for the treatment of OSA in Japan, and considered an evaluation of their effects to benecessary. Clinical practice guidelines were developed using the Grading of Recommendations, Assessment, Development, and Evaluation（GRADE）system. We recommend OAs that advanced the mandible forward and limited mouth opening for patients with OSA.However, CPAP should be used by patients for whom it has been indicated. OAs are desirable for those who cannot use CPAP（GRADE 1B, strong recommendation/quality of evidence, “Moderate quality”）. The long-term effects and side effects, OSA severity, and comorbidities of OA therapy were not examined, which represented a limitation to the present study. In future studies, the Japanese Academy of Dental Sleep Medicine plan to update clinical practice guidelines for oral appliances used in OSA

Enhancement of pre-pulse and picosecond pedestal contrast of the petawatt J-KAREN-P laser

We have experimentally improved the temporal contrast of the petawatt J-KAREN-P laser facility. We have investigated how the generation of pre-pulses by post-pulses changes due to the temporal overlap between the stretched pulse and the post-pulse in a chirped-pulse amplification system. We have shown that the time at which the pre-pulse by the post-pulse generates and its shape are related to the time difference between the stretched main-pulse and the post-pulse. With this investigation, we have found and identified the origins of the pre-pulses and have demonstrated removal of most pre-pulses by eliminating the post-pulse with wedged optics. We have also demonstrated the impact of stretcher optics on the picosecond pedestal. We have realized orders of magnitude enhancement of the pedestal by improving the optical quality of a key component in the stretcher