Decision-tree analysis on optimal release of reservoir storage under typhoon warnings

The wet and dry seasons are distinctive in Taiwan as the amount of precipitation in wet seasons accounts for over three-fourth of the total rainfall. And the water-resources management relies pretty much on the rainfall brought in by typhoons as it accounts for a significant portion of the precipitation during wet seasons. Furthermore, as the storage of reservoirs is limited due to topographical factors, the management of typhoon rainfall has always been an important issue in Taiwan. The technique of decision-tree analysis is applied in this article to determine the optimal reservoir release in advance upon the issuance of a typhoon warning by the Central Weather Bureau (CWB), and the proposed methodology may provide solution to the trade-off judgment of reservoir operations between flood control and water supply according to economic efficiency. In this article, the economic loss functions of flooding damage and water-supply shortage are assumed in linear and nonlinear conditions, and the respective expected optimal releases based on the predicted precipitation as issued by CWB are derived. The proposed methodology has been applied to the Shihmen Reservoir System, and the capabilities of the model as an aid to real-time decision-making as well as the evaluation of the economic worth of forecasts is presented.     

Green supply chain management in the electronic industry

Green supply chain management has emerged as a proactive approach for improving environmental performance of processes and products in accordance with the requirements of environmental regulations. Various approaches for implementing green supply chain management practices has been proposed and recognized in previous literatures, yet no investigation has identified the reliability and validity of such approaches particularly in electronic industry. This study examines the consistency approaches by factor analysis that determines the adoption and implementation of green supply chain management in Taiwanese electronic industry. The fuzzy analytic hierarchy process method is applied to prioritize the relative importance of four dimensions and twenty approaches among nine enterprises in electronic industry. The findings indicate that these enterprises would emphasize on supplier management performance in the crucial role of implementing green supply chain management. Establishing an environmental database of products, asking for product testing report and top management support are among the most important approaches. The results for the implications of green supply chain management implementation in electronic industry investigated in this work generate a generic hierarchy model for decision-makers who can prioritize those approaches for implementing green supply chain management in Taiwan.     

Teaching Topographic Map Skills and Geomorphology Concepts with Google Earth in a One-Computer Classroom

Teaching high-school geomorphological concepts and topographic map reading entails many challenges. This research reports the applicability and effectiveness of Google Earth in teaching topographic map skills and geomorphological concepts, by a single teacher, in a one-computer classroom. Compared to learning via a conventional instructional method, students learning with Google Earth do not have different geomorphological concepts development because both settings enable students to learn with similar static representation. However, students learning with Google Earth improve topographic map skills significantly compared to the conventional instructional method. This is because of the 3D landscape visualization and prior knowledge connections available with Google Earth.     

Building vulnerability to debris flows in Taiwan: a preliminary study

In quantitative risk analyses for natural hazards, vulnerability can be expressed as the ratio of reconstruction, replacement or reproduction expenses due to a damage caused by a certain process intensity and the original value of the element at risk exposed. To discuss the building vulnerability under debris flow events, the ratio is mostly related to debris flow inundation height, building materials and building values. Different types of buildings would resist to the impact of debris flows differently, resulting in different damage levels even under the same inundation height. After debris flow events, the damages to a building include the content loss and the structure loss, which is also variable due to the individual building conditions. This study proposes a flowchart to establish building vulnerability curves through estimating the damages to buildings after debris flow hazards. The losses of content and structure are firstly calculated separately to obtain the loss ratios with respect to original buildings. Secondly, by combining the content and structure loss ratio, the building vulnerability function is derived. In this paper, the original building content value was obtained from governmental statistic records and was based on the market price, and the structure value was received from a regional architecture office. The losses resulting from debris flow impacts were synthetically derived following field surveys. To combine the content and structure losses, a unit building with a floor area of 60?m² was assumed. The result shows that due to a higher percentage of content value compared with the total building value, the loss ratio resulting from debris flows in Taiwan is higher compared with European studies, in particular with respect to high-frequency but low-magnitude events. The concept of obtaining building vulnerability is particularly suitable for regions where well-documented building loss records are unavailable.     

Dynamics of deformation and water flow in heterogeneous porous media and its impact on soil properties

The interaction of geomechanics and flow within a soil body induces deformation and pore pressure change. Deformation may change hydrogeological and elastic properties, which alters the mechanical behaviour and results in non‐linearity. To investigate this interaction effect in a heterogeneous porous medium, a stochastic poroelastic model is proposed. Monte Carlo simulations are performed to determine the mean and uncertainty of the parameter changes, displacement, and change in pore water pressure. Hydraulic conductivity is treated as the only random variable in the coupled geomechanics‐flow system due to its large variation compared to other mechanical and hydrogeological properties in natural environments. The three considered non‐linear models for the interaction between parameters and deformation are those that consider (1) porosity and hydraulic conductivity; (2) porosity and Young's modulus; and (3) a combined effect that includes porosity, hydraulic conductivity, and Young's modulus. Boundary effects on the coupled system are also explored. The relationships between changes of porosity, hydraulic conductivity, and Young's modulus are analytically shown to be non‐linear. Among the considered parameters, the deformation effect induces the largest reduction in hydraulic conductivity. The deformation‐induced change in hydraulic conductivity shows the most significant effect on the mean and variance of the change in pore water pressure and displacement, while changes in Young's modulus have the least effect. When the deformation effect is considered, the superposition relationship does not exist in the mean displacement and mean change in pore water pressure for the three scenarios considered; it exists for the case without deformation effects. Deformation also causes a reduction in the effective hydraulic conductivity for the whole domain. The scenario that considers both loading and discharge boundaries has larger changes in hydrogeological and geo‐mechanical parameters than those in scenarios that consider loading and discharge boundaries separately. The results indicate that the interaction between deformation and changes in parameters has a profound effect on the poroelastic system. The effect of deformation should thus be considered in modelling and practice. Copyright © 2009 John Wiley & Sons, Ltd.     

Modelling the hydrologic effects of dynamic land‐use change using a distributed hydrologic model and a spatial land‐use allocation model

This study develops a novel approach for modelling and examining the impacts of time–space land‐use changes on hydrological components. The approach uses an empirical land‐use change allocation model (CLUE‐s) and a distributed hydrological model (DHSVM) to examine various land‐use change scenarios in the Wu‐Tu watershed in northern Taiwan. The study also uses a generalized likelihood uncertainty estimation approach to quantify the parameter uncertainty of the distributed hydrological model. The results indicate that various land‐use policies—such as no change, dynamic change and simultaneous change—have different levels of impact on simulating the spatial distributions of hydrological components in the watershed study. Peak flow rates under simultaneous and dynamic land‐use changes are 5·71% and 2·77%, respectively, greater than the rate under the no land‐use change scenario. Using dynamic land‐use changes to assess the effect of land‐use changes on hydrological components is more practical and feasible than using simultaneous land‐use change and no land‐use change scenarios. Furthermore, land‐use change is a spatial dynamic process that can lead to significant changes in the distributions of ground water and soil moisture. The spatial distributions of land‐use changes influence hydrological processes, such as the ground water level of whole areas, particularly in the downstream watershed. Copyright © 2010 John Wiley & Sons, Ltd.     

Minor element zoning and trace element geochemistry of pallasites

Abstract— I report here on an ion probe study of minor element spatial distributions and trace element concentrations in six pallasites. Pallasite olivines exhibit ubiquitous minor element zoning that is independent of grain size, morphology, and adjacent phases. Ca, Cr, Ti, V, and Ni concentrations decrease from center to rim by factors of up to 10, while Mn is generally unzoned or increases slightly at the very edge of some olivine grains. The maximum concentrations of these elements at the center of olivine vary from grain to grain within the same meteorite and among the pallasites studied. These zoning profiles are consistent with thermal diffusion during rapid cooling. The inferred cooling rates at high temperature regimes are orders of magnitude faster than the low‐temperature metallographic cooling rates (?0.5 to 2°C/Ma). This suggests that pallasites, like mesosiderites, have experienced rather complicated thermal histories, i.e., cooling rapidly at high temperatures and slowly at low temperatures. Pallasite olivines are essentially free of REEs. However, the phosphates display a wide range of REE abundances (0.001 to 100 x CI) with distinct patterns. REEs are generally homogeneous within a given grain but vary significantly from grain to grain by a factor of up to 100. Albin and Imilac whitlockite are highly enriched in HREEs (?50 x CI) but are relatively depleted in LREEs (?0.1 to 1 x CI). Eagle Station whitlockite has a very unusual REE pattern: flat LREEs at a 0.1 x CI level, a large positive Eu anomaly, and a sharp increase from Gd (0.1 x CI) to Lu (70 x CI). Eagle Station stanfieldite has a similar REE pattern to that of whitlockite but with much lower REEs by a factor of 10 to 100. Springwater farringtonite has relatively low REE concentrations (0.001 to 1 x CI) with a highly fractionated HREE‐enriched pattern (CI‐normalized Lu/La ?100). Postulating any igneous processes that could have fractionated REEs in these phosphates is difficult. Possibly, phosphates were incorporated into pallasites during mixing of olivine and IIIAB‐like molten Fe. These phosphates preserve characteristics of a previous history. Pallasites have not necessarily formed at the mantle‐core boundary of their parent bodies. The pallasite thermal histories suggest that pallasites may have formed at a shallow depth and were subsequently buried deep under a regolith blanket.     

Storm Surges in New York During Hurricane Sandy in 2012: A Verification of the Wind-Stress Tide Relation

In October 2012 Hurricane Sandy devastated New York City and its vicinity caused mainly by the storm surge, which is the water height above normal astronomical tide level. The meteorological conditions were as follows: minimum central pressure, 962 hPa, highest sustained wind speed 27.1 m s $^{-1}$ ? 1 and maximum gust 37.8 m s $^{-1}$ ? 1 . The peak storm surge was at 3.9 m and the peak storm tide at 4.4 m (which is referenced above mean lower low water). The wind-stress tide relation shows that $S=K\,V^{2}$ S = K V 2 , where $S$ S is the storm surge, $V$ V is the wind speed and $K$ K is the coefficient. It is found that with $S$ S in units of m, and $V$ V in  m s $^{-1}$ ? 1 , $K = 0.0051$ K = 0.0051 with $R^{2}= 0.91$ R 2 = 0.91 ( $R$ R is the correlation coefficient) indicating that 91 % of the total variation of the storm surge can be explained by variations in the wind stress, which is proportional to $V^{2}$ V 2 . Similar results were obtained during Hurricane Irene in 2011, which also affected the New York area. Therefore, this simple wind stress-tide relation should be useful in coastal engineering, urban planning, and emergency management.