Investigation of Trafficability of Agricultural Machinery on Reclamation Field

農業機械の利用の立場から干拓畑における機械の走行性を調査するため,SR-2型土壌抵抗測定器を用いて,円錐貫入抵抗試験,沈下試験,剪断試験,摩擦試験ならびにコンシステンシー指数の測定を,暗渠排水を行い,数年聞蔬菜類を栽培した圃場において行った.その結果,畝の溝部においては,貫入抵抗は約10kg/cm2(小コーンで表面下0-15cm),矩形板沈下量は約0.1cm以内(小プレートで荷重30kg),剪断抵抗は約0.5kg/cm2(荷重25kg),摩擦抵抗は約0.25kg/cm2(荷重25kg),コンシステンシー指数は約1.0であり,農業機械の利用はほぼ可能であると言えた

Vibration Characteristics of Multi-Wheel Off-Road Vehicles

農用不整地車両として多車輪(6輪)車両を用い,その振動特性を上下方向の加速度を中心に,実験的に検討し,次のような結果を得た. 1.アスファルトのように路面が良好で,凹凸による外力がほとんど無視できる条件下では,振動におよぼす車輪数や走行速度の影響はほとんどみとめられず,車輪ラグによる振動成分が支配的である. 2.単一障害物を乗り越す時の挙動では,4輪と6輪でその特性は異なり,6輪では最後輪が障害物を越し終えた時点で衝撃荷重を受けたような挙動を示すが,4輪では,各軸の車輪が障害物を登り始めるときに,ピーク加速度がみられる. 加速度の大きさについてみると,最大値は低速では6輪の方が大きいが,高速になるにつれ,4輪の方が大きくなる. 3.農道のように不規則な凹凸の路面走行時は,6輪の場合,常に全車輪が接地することは少なく,車両の支持状況が刻々変化することにより,車両の固有振動数を変化さすことになり,共振減少効果がみられ,4輪に比較して,乗心地に対し,多車輪の有効性がみとめられる. 4.規則的な波長をもつ周期波状路面を走行した場合,加遠度の大きさについてみると,走行速度が増加するにつれ,4輪の場合が大きくなり. 増加の割合も6輪に比べ大きい. また,路面波長と,車両の軸距が一致する場合は,多車輪の効果も減少し,大きな加速度がみられる. 以上のように不整地を走行する多車輪車両を,振動乗心地面からみるとき,走行速度の増加と共に多車輪の効果がみとめられた

Rigorous numerical computations for 1D advection equations with variable coefficients

This paper provides a methodology of verified computing for solutions to 1D advection equations with variable coefficients. The advection equation is typical partial differential equations (PDEs) of hyperbolic type. There are few results of verified numerical computations to initial-boundary value problems of hyperbolic PDEs. Our methodology is based on the spectral method and semigroup theory. The provided method in this paper is regarded as an efficient application of semigroup theory in a sequence space associated with the Fourier series of unknown functions. This is a foundational approach of verified numerical computations for hyperbolic PDEs. Numerical examples show that the rigorous error estimate showing the well-posedness of the exact solution is given with high accuracy and high speed

Dark Matter before the LHC in a Natural Supersymmetric Standard Model

We show that the solid lower bound of about 10^{-44} cm^2 is obtained for the cross section between the supersymmetric dark matter and nucleon in a theory in which the supersymmetric fine-tuning problem is solved without extending the Higgs sector at the weak scale. This bound arises because of relatively small superparticle masses and a fortunate correlation that the two dominant diagrams for the dark matter detection always interfere constructively if the constraint from the b -> s \gamma measurements is obeyed. It is, therefore, quite promising in the present scenario that the supersymmetric dark matter is discovered before the LHC, assuming that the dark matter is the lightest supersymmetric particle.Comment: 9 pages, 3 figure

Predictive Supersymmetry from Criticality

Motivated by the absence of any direct signal of new physics so far, we present a simple supersymmetric model in which the up-type Higgs mass-squared parameter crosses zero at a scale close to the weak scale. Such a theory may be motivated either by the conventional naturalness picture or by the landscape picture with certain assumptions on prior probability distributions of parameters. The model arises from a simple higher dimensional setup in which the gauge and Higgs fields propagate in the bulk while the matter fields are on a brane. The soft supersymmetry breaking parameters receive contributions from both moduli and anomaly mediations, and their weak scale values can be analytically solved for in terms of a single overall mass scale M. The expected size for M depends on whether one adopts the naturalness or landscape pictures, allowing for the possibility of distinguishing between these two cases. We also present possible variations of the model, and discuss more general implications of the landscape picture in this context.Comment: 18 pages, 4 figures, reference adde