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  • Author: K. Mori x
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Variable Data Flow Management in Wireless Sensing Network for Landslide Disaster

Sensing systems to monitor natural disasters face many hard conditions. Natural disasters occur suddenly, and damage the sensor system. Therefore, the sensor system should be designed as a distributed node network. In addition to that, the network should have some characteristic functions, such as self-recovery, autonomous operation and effective data transmission. This paper describes an effective data flow management in wireless sensing node network for landslide disasters. The sensing node network is operated by three modes (initializing, measuring and urgent). By switching these operation modes autonomously, the sensing node network becomes a robust system (loss/insert) of sensing node and the dynamic control of data transmission. Finally, the effectiveness of the operation is supported by some experiments.

Summary

The effects of low molecular weight phenolic resin impregnation and high pressure hot pressing (150°C, 30–100 MPa) on the physical and mechanical properties of wood were first investigated by using sawn wood prepared from a block of Japanese birch (Betula meximowicziana). Subsequently, the effects of element size and orientation were examined by using sliced veneers, particles and powder prepared from the remaining portion of the block. Due to the combination of resin impregnation and hot pressing under high pressure, the specific bending strength at 20°C and 65% RH of sawn wood increased 50% accompanied by enormous decreases in moisture content, and bending strength reached around 400 MPa. The mechanical properties of veneer laminated product did not differ significantly from those of sawn wood product. Among isotropic products, the highest bending strength at 20°C and 65% RH of plywood, particleboard and powderboard was 242 MPa, 166 MPa and 175 MPa, respectively. The difference of bending strength between plywood and other isotropic products could be explained by the difference in element orientation, cross lamination and random distribution. Furthermore, the results for the particleboard and powderboard showed that when the resin impregnated elements were hot pressed under high pressure, a decrease in element size did not result in a decrease in bending strength.

Abstract

The temperature dependence of the 81Br NQR frequencies (vD) for uncoordinated Br- ions in trans-[CoBr2(en)2] [D5O2]Br2(D) has been determined by a continuous-wave spectrometer. vD amounted to 16.200 MHz at 273 K. This is lower by 418 kHz than the 81Br NQR frequency (vH) for trans-[CoBr2 (en2] [H5O2 ]Br2 (H). The frequency difference (Δv = vH -vD) remained almost constant in the temperature range studied. A shortening of the O-H bond length caused by deuteration could explain the magnitude and the sign of Av on the basis of a point charge model calculation. The compounds D and H yielded 81Br NQR lines in the range 110-320 K and 90-343 K, respectively. As to the 59Co NQR frequencies (7/2 - 5/2), the observed isotope frequency shifts (Δv1 = v1H - v1D) between D and H were smaller than 5 kHz. Below 160 K, 59Co resonances were only available by pulsed experiments. 59Co NQR spin-lattice relaxation times T1Q of 0.54 ms at 194 K and 4.8 s at 77 K for H have been observed.