Prof. Hengjia Zhang
Gansu Agricultural University, China
Title: Optimization of Limited Irrigation Schedules for Spring Maize (Zea mays) in a Desert Oasis Region
Abstract: An experiment was carried out to optimize limited irrigation (LI) schedules for spring maize in a desert oasis region. The grain yield, water use efficiency (WUE), irrigation water use efficiency IWUE), and integrated evaluation index for soil nutrients (IEISN) in 0～40 cm soil depth of maize field subject to LI were selected as the synthetical factors in evaluating and optimizing the LI schedules. The unifactor Matrix and weighing coefficient matrixes of evaluating factors were formed for fuzzy judgement and the synthetical evaluation index (SEI) determination. Compared to the minimum in MI4, the SEI for spring maize was respectively improved by 46.5﹪, 20.9﹪, 38.9﹪, 27.8﹪, and 3.8﹪in MI1, MI2, MI3, MI5, and CK. Therefore, the MI1irrigation regime was recommended as the optimized LI schedule for spring maize in the desert oasis region due to its maximum SEI caused by the least water application, maximum grain yield, WUE, and IWUE, and 95.2﹪of the maximum IEISN.
Prof. Shaohua Marko Hsu
Feng Chia University
Title: Using Porous Material for Riverbank and Riverbed Protection
Abstract: After observation in series laboratory experiments, Porous Cylinders were tested for levee protection in the downstream Da-jia River at Kch-Juang reach,Taiwan. Morphological situation of the river is braided with steep slope and the bed material is mainly composed of gravel and cobble. In the middle of a main stream and with considerable distance away from the protected levee on river bank, four lines of porous cylinders were installed and arranged across a deep channel flowing towards the protected levee, which was reconstructed from a broken situation due to previous strong flow events. After the porous cylinders were initially installed in March, and before any major flood, the river-bed elevation around the installed porous cylinders was measured as a background reference. Since then, the East-Asian rainy season (plum rain) occurred in June, the Typhoon Sepat came in August, the Typhoon Wiptha came in September, and the Typhoon Krosa came in October. Elevation surveys between each strong-flow event indicate that the porous cylinders slowed down strong flow past them and caused deposition behind most cylinders which can reach 1.5 to 2.0 m. Also, the major deep channel was divided into several paths, which detoured to different orientation from the original ones and mainly detoured along the line-up direction of the porous cylinders. As a result, levee protection achieved due to this behind-cylinder deposition as well as detour of original deep channel which reduced the angle of attack onto the levee.
Prof. Ahmad Safuan Bin A. Rashid
Universiti Teknologi Malaysia, Malaysia
Title: Application of UAV-TLS Photogrammetry in Determination of Rock Slope Stability
Abstract: Identify the characterization and orientation of the discontinuities such as joint, bedding, and fault is a requirement in rock slope stability analysis because discontinuities control the type of failure. Until today, geologists still practice the classical method to determine the dip and strike of discontinuities which is by using Brunton compass at the field. Difficulty to measure at the inaccessible area, dangerous when having physical contact with the steep, fractured slope and time consuming to cover a large area are limitations of this method in analyzing the rock slope stability. A recent development in remote sensing has introduced Terrestrial Laser Scanner (TLS) and Unmanned Aerial Vehicle (UAV) as an indirect method in monitoring and mapping the rock slopes at a larger area. Thus, this study is to obtain the dip and dip direction of the joints on the rock slope by combining the point cloud data of 3D coordinates of objects surfaces with a high precision measurement from the TLS and UAV. The orientations of discontinuities that have been extracted from the rock slope using Scan master software were then imported into the Rocscience Dips Version 7.0 software. The kinematic analysis feature of this software provides a quick check for various rock slope stability failure modes on a stereonet plot, such as planar sliding, wedge sliding, and flexural toppling with just input on slope orientation, friction angle and lateral limits, before selecting the failure modes. By using discontinuity data, the kinematic analysis of the hybrid point cloud data shows that the Line1 of the rock slope has 15.22% risk for wedge sliding while the direct method gives14.10% risk for wedge sliding. This study shows that the dip and trend of the joints from the digital photogrammetry show similarity to the result obtain directly on-site by using the Brunton compass. Hence, a combination of UAV and TLS as a tool in rock slope characterization is reliable because it can provide valuable preliminary information on rock slope stability assessment.
More information, coming soon....