Monitoring and forecasting of winter wheat freeze injury and yield from Multi-temporal remotely-sensed data

Wang Hui-fang, Guo wei, Wang Ji-hua, Huang Wen-jiang, Gu Xiao-he, Dong Ying-ying and Xu Xin-gang

Remote sensing techniques provide crop growth information economically, rapidly and objectively on a large scale. It has been widely used in monitoring crop growth and forecasting yield. In this study, HJ-CCDs images were acquired in Gaocheng areas at four growth-wintering stages of winter wheat (Dec. 2, 2009, pre-freeze injury), regreen stage (Apr. 2, 2010, post-freeze injury), jointing stage (Apr. 23, 2010) corresponding with field investigations data. According to the change characteristics of normalized difference vegetation index (NDVI) of field samplings of post-freeze injury, a mutil-line-progress model (MLR) was built between the NDIV difference (ΔNDVI) and field samplings. The damage levels (uninjured, light, moderate and serious) and the growth levels (better, good, bad and worse) were also specified. As a result, the coefficient of determination (R2) of this model reached 0.6001; twenty sampling points were used to validate the model and R2 reached 0.5255. This study not only proved the feasibility of using early growth stage model to predict yield but also provided a tentative prediction of the yield in Hebei area using HJ-CCD images of China.

Full Text

Choice of different numbers of forecasting factors for Medium and Long-term Runoff Forecasting

You Hailin, Xu Ligang and Wu Yongming

Dahuofang Reservoir, Liaoning Province in China, is taken as the case study in this paper. Two kinds of models are developed for medium and long-term runoff forecasting and are used to verify the importance of choosing the hydrological forecasting factors on accuracy for two models. According to hydrologic and climatic characteristics of Dahuofang Reservoir watershed, based on physical and relevant statistical analysis, 10 common elements are selected from physics of the atmosphere, ocean and astronomy as the hydrological forecasting factors to establish the first model. First, Principal Component Analysis method (PCA) is used to extract integrated factors affecting annual runoff change from 10 common elements; Secondly, the integrated factors are simulated by the logistic equation; finally, multiple linear regression runoff forecasting model is developed. On the same background conditions of the first model, combined with field work and local people's experiences, two most important factors are selected from 10 common elements as the hydrological forecasting factors to establish the second model which is weight least square regression runoff forecasting model. The results show that first model has higher accuracy of simulation and prediction compared with the second model. High accuracy runoff forecasting is helpful in guiding function on the prevention of flood and drought for government.

Full Text

Research on the representation of granular vertical size grading and numerical simulation method with the typical waste rock site

Wang Guang-jin, Kong Xiang-yun, Yang Chun-he and Xu Yun-hong

Vertical size grading of granular, as a typical characteristic with the high single-bench waste rock site, is an important factor affecting slope stability of the waste rock. On the basis of the on-site survey of granular size distribution of the typical waste rock site located in Jiangxi, we used Cellular Automaton method to develop HHC-Granular model which could describe the features of apparent vertical size grading. Moreover, we constructed the slope model of current situation where the size grading was included considered based on the data collected from the typical waste rock site with the aid of Flac3D software. The slope stability and various piling up patterns had been analyzed using the developed slope model of current situation. The results indicated that if the slope failure model of current situation had crack at the top platform and shearing out with a arc in the middle, then the current situation slope was at temporarily steady stage. To adopt full overlay dump of multi-bench, the displacement vector of waste rock site slope showed subsidence at the top and transited to the horizontal direction at the bottom. The slope failure mode expressed in crack at the top platform shearing out with an arc at the bottom. When the strength characteristics of granular was considered as the only factor on the slope stability analysis, the vertical size grading of high-bench waste rock site was helpful to slope stability.

Full Text

Reinforcement of Longtan Bridge with Stickup Carbon Fiber Reinforced Polymer

Sun Hongling, Zhang Aiping and Cao Jiangtao

Carbon Fiber reinforced Polymer (CFRP) is a kind of material with excellent performance parameters. Through the research and application of more than ten years, it has been widely used in engineering. This paper deals mainly with research methods of the bridge flexural reinforcement using carbon fiber reinforced polymer and is based on the detection, evaluation and reinforcement of the “Lan Cheng Yu” product oil pipeline-Longtan Bridge which was influenced by “5.12” Wenchuan Earthquake.

Full Text

Managing Natural Hazards in India

Mishra Ashutosh

Natural disasters like earthquake, landslide, flood, drought, cyclone, forest fire, volcanic eruption and epidemic are quite common in different parts of the globe; however, their impact is greater in developing countries where they occur very often. In most cases, the occurrence of natural disasters in these countries is due to two main factors. First, there is a relation with geographical location and geological – geomorphological settings. Developing or poor countries are located to a great extent in zones largely affected by volcanic activity, seismicity, flooding, etc. The second reason is linked to the historical development of these poor countries where the economic, social, political and cultural conditions are not good and consequently act as factors of high vulnerability to natural disasters (economic, social political and cultural vulnerability).

Full Text

Satellite-based Detection of Compounding Column of Ozone and Thermal Infrared Precursor Behavior to Earthquake Occurrence

Pirasteh S. and Li Jonathan

The theory exploring mechanism of the earthquake occurrence has been an intriguing part of research interest for scientists so far. Compounding of physical phenomena of pre-earthquake thermal infrared (TIR) and the column ozone (O3) concentration anomaly has been attempted for the Bam earthquake occurred on December 26, 2003 in Iran. Thermal infrared satellite data analysis revealed the land surface temperature (LST) rise ranging from 5°–10°C in and around epicenter areas. In addition, the research showed a significance anomaly of ozone concentration (column density) between 15 Du to 25 Du, few days prior to the main shock and after the shock. The study shows that a promising correlation between land surface temperature and column density for ozone (O3) can be established. The thermal anomalies started developing about 1–5 days prior to the main event depending upon the magnitude and focal depth and disappeared after the main shock. Monitoring of radioactive radiations and reactionary hypothesis of gases before and after quake in conjunction with TIR, probably could give us a clue to understand near real time earthquake forecasting in the region.

Full Text

Regional groundwater flow modeling in Lower Bhavani River basin, Tamil Nadu, India

Anandakumar S. and Subramani T.

Groundwater flow models are beneficial for the management of groundwater resources as they give an approximate estimate about the various hydrogeological parameters. They also help in illustrating a clear picture of the flow pattern in an aquifer. Such a numerical three-dimensional groundwater modeling study was attempted in Lower Bhavani River basin, South India with the main objectives of simulating the regional groundwater flow and identification of the distribution of heads for improved understanding of the natural flow system. Bhavani River is one of the important tributaries of Cauvery River and originates in the Silent Valley range of Kerala State, India. The model simulates groundwater flow over an area of 2,475 km2 with 55 rows and 45 columns, with a single vertical layer. The model was simulated in transient state condition using three-dimensional partial differential equation of groundwater flow from 1995-2006. The model was calibrated for steady and transient state conditions. There was a reasonable match between the computed and observed heads. The transient model will run until the year 2015 to forecast the dynamic groundwater flow under various scenarios of over pumping and less recharge. The model predicts the behavior of this aquifer system under various hydrological stress conditions. The results indicate that the aquifer system is stable under the present conditions. The model also predicts the changes in groundwater head with changes in hydrological conditions like drought occurring once in three years and a normal run for another 8 years without any major changes.

Full Text

Numerical analyses of smoke control in a 12-inch wafer clean room

Chen-Wei Chiu

This study carried out practical smoke flow analyses by CFD simulation and evaluated property protection in a 12−inch wafer fabrication zone. An upward smoke exhaust system incorporated a decrease in filter fan unit (FFU) air supply rate in ignition fire zone to determine whether such a design could achieve a better equivalent performance based on smoke control efficiency. The designed fires were small fires (0.6W), medium fires (1.2MW) and big fires (2.4 MW) respectively, typically higher frequent fire scenarios in clean rooms. In addition, the smoke management system can still be utilized provided it complies with some restrictions in fire protection design, for example, materials used and the provision of an acceptable emergency response plan. According to CFD simulation results, the study found that a decreasing FFU air supply rate produced accelerated smoke flow, spreading smoke to corner smoke compartments of the semi-conductor clean room; therefore, high-value equipment should be placed in the center of the clean room for the purposes of property protection. When big fires occur, smoke flow becomes faster and larger due to a 0.25 m/s FFU downward air supply rate; therefore, for property protection, high−value added manufacturing equipment and properties should be placed in the center of the clean room.

Full Text