TREE ROOT ENCROACHMENT ON LEVEE DRAINAGE SYSTEM

The objectives of this study were to estimate the influence of roots on the drainage facilities associated with the levees along the middle Rio Grande (MRG), and to suggest an appropriate drainage design. This study consists of three research elements: (1) GIS-based analysis in estimating root distribution along levees, (2) a bench-top experiment, and (3) evaluating a drainage designs using a numerical model. First, tree crown sizes were measured on GIS-based aerial photography to estimate root distributions. The results were compared with vegetation maps that were created based on field observations. The GIS-based measurements and field measurements showed similar values if the site was covered with a simple vegetation community. Simple canopy shapes improved the precision of the measurements. However, the GIS-based measurement was not accurate for a site with complex vegetation coverage. The bench-top experiment was conducted to evaluate the effectiveness of two types of geosynthetics as root barriers. A geotextile and a geocomposite were tested in v clear columns filled with soil and/or gravel to simulate six different drainage designs. Two New Mexican plants, Rio Grande cottonwood (Populus deltoides ssp. wislizeni) and coyote willow (Salix exigua), were selected, and planted in columns. The results showed roots of both species could penetrate through the geotextile and geocomposite. Also, root growth was not affected by the types of root barriers nor drainage material. For the last study element, HYDRUS-2D was applied to understand the soil water movement in the levee. The typical toe drain and the geocomposite edge drain were considered, and the models were run under the ambient condition (unsaturated) and the flood condition (saturated). As a result, the functions of both drainage designs were close to identical under the ambient condition since it did not result in drainage. In contrast, under the flood condition, the geocomposite edge drain could remove excess water more efficiently than the conventional toe drain

Numerical evaluation of vortex-induced vibration amplitude of a box girder bridge using forced oscillation method

The evaluation of the amplitude of the vortex-induced vibration (VIV) of a long-span bridge is necessary to implement a wind-resistant design. The development of high-performance computing has led to the use of computational fluid dynamics (CFD) in this domain, but the evaluation of VIV amplitude using the free vibration method in CFD incurs a high computational cost because of the small negative aerodynamic damping in the wind speed region of VIV. In this study, the use of flutter derivatives based on the forced oscillation method with a large eddy simulation is proposed for evaluating the VIV amplitude to reduce computational cost. The heaving VIV amplitude of a box girder was evaluated using simulated flutter derivatives and the results were validated by corresponding free vibration wind tunnel tests. Because the aerodynamic damping obtained by the flutter derivatives showed a clear dependence on the oscillation amplitude, the VIV amplitude can be evaluated using the proposed method. The effects of the spanwise domain size and Reynolds number were also significant

Characteristics of the Changes in the Compressive and Tensile Stress of the Construction Sealant under Cyclic Movement

A compact fatigue testing machine to quantitatively evaluate the effects of this complex degradation of sealants and the load change of the sealant under dynamic fatigue has been developed. The developed fatigue testing machine is compact with dimensions of (width) 100 × (length) 135 × (height) 110 mm. It can be installed in an outdoor exposure test site or in a chamber. Thus, this machine can be used for performing various compounded accelerated degradation tests. We report the use of this testing machine to examine the effects of this complex degradation of sealants and the load change of the sealant under dynamic fatigue

Identification of hepta-histidine as a candidate drug for Huntington's disease by in silico-in vitro- in vivo-integrated screens of chemical libraries.

We identified drug seeds for treating Huntington's disease (HD) by combining in vitro single molecule fluorescence spectroscopy, in silico molecular docking simulations, and in vivo fly and mouse HD models to screen for inhibitors of abnormal interactions between mutant Htt and physiological Ku70, an essential DNA damage repair protein in neurons whose function is known to be impaired by mutant Htt. From 19,468 and 3,010,321 chemicals in actual and virtual libraries, fifty-six chemicals were selected from combined in vitro-in silico screens; six of these were further confirmed to have an in vivo effect on lifespan in a fly HD model, and two chemicals exerted an in vivo effect on the lifespan, body weight and motor function in a mouse HD model. Two oligopeptides, hepta-histidine (7H) and Angiotensin III, rescued the morphological abnormalities of primary neurons differentiated from iPS cells of human HD patients. For these selected drug seeds, we proposed a possible common structure. Unexpectedly, the selected chemicals enhanced rather than inhibited Htt aggregation, as indicated by dynamic light scattering analysis. Taken together, these integrated screens revealed a new pathway for the molecular targeted therapy of HD

Effect of Reduction in Thickness and Rolling Conditions on Mechanical Properties and Microstructure of Rolled Mg-8Al-1Zn-1Ca Alloy

A cast Mg-8Al-1Zn-1Ca magnesium alloy was multipass hot rolled at different sample and roll temperatures. The effect of the rolling conditions and reduction in thickness on the microstructure and mechanical properties was investigated. The optimal combination of the ultimate tensile strength, 351 MPa, yield strength, 304 MPa, and ductility, 12.2%, was obtained with the 3 mm thick Mg-8Al-1Zn-1Ca rolled sheet, which was produced with a roll temperature of 80°C and sample temperature of 430°C. This rolling process resulted in the formation of a bimodal structure in the α-Mg matrix, which consequently led to good ductility and high strength, exclusively by the hot rolling process. The 3 mm thick rolled sheet exhibited fine (mean grain size of 2.7 μm) and coarse grain regions (mean grain size of 13.6 μm) with area fractions of 29% and 71%, respectively. In summary, the balance between the strength and ductility was enhanced by the grain refinement of the α-Mg matrix and by controlling the frequency and orientation of the grains

Early Results of a Wildfire Monitoring Microsatellite UNIFORM-1

UNIFORM (UNiversity International FORmation Mission) is a capacity building program in microsatellite field including satellites, ground stations, and data platform. The program, sponsored by the Ministry of Education, Culture, Sports and Technology (MEXT) of Japan, aims to increase the number of players in the small satellite community through education of both domestic and international young engineers, by providing them with an opportunity to study, build, and operate microsatellites. The first satellite of the program, UNIFORM-1 was launched on May 24th 2014. UNIFORM-1 is a 50-kg earth observation satellite whose mission is wildfiremonitoring using a microbolometer. Since then it has been in operation, successfully capturing several events on the ground including wildfires and volcanic activities. This paper presents in-orbit results of UNIFORM-1 mission, critical bus subsystems including EPS and AOCS, and lessons learned from its operations