Future Hydrological Drought Analysis Considering Agricultural Water Withdrawal Under SSP Scenarios

Hydrological drought is assessed through river flow, which depends on river runoff and water withdrawal. This study proposed a framework to project future hydrological droughts considering agricultural water withdrawal (AWW) for shared socioeconomic pathway (SSP) scenarios. The relationship between AWW and potential evapotranspiration (PET) was determined using a deep belief network (DBN) model and then applied to estimate future AWW using projections of the twelve global climate models (GCMs). 12 GCMs were bias-corrected using the quantile mapping method, climate variables were generated, and river flow was estimated using the soil and water assessment tool (SWAT) model. The standardized runoff index (SRI) was used to project the changes in hydrological drought characteristics. The results revealed a higher occurrence of severe droughts in the future. Droughts would be more frequent in the near future (2021–2060) than in the far future (2061–2100) and more severe when AWW is considered. Droughts would also be more severe for SSP5-8.5 than for SSP2-4.5. The study revealed that the increased PET due to rising temperatures is the primary cause of the increased drought frequency and severity. The AWW will accelerate the drought severities in the future in the Yeongsan River basin.

     

Identification of Spatial Ranking of Hydrological Vulnerability Using Multi-Criteria Decision Making Techniques: Case Study of Korea

Potential flood damage (PFD), potential streamflow depletion (PSD), potential water quality deterioration (PWQD), and watershed evaluation index (WEI) have been developed to spatially quantify the hydrological vulnerability using multi-criteria decision making (MCDM) techniques. All criteria are selected on the basis of a sustainability evaluation concept (pressure-state-response model), and their weights are estimated by an Analytic Hierarchy Process, which is also a type of MCDM technique. The MCDM techniques used for the evaluation are composite programming, compromise programming, ELECTRE II, Regime method, and Evamix method; these techniques can be classified according to data availability and objectives (prefeasibility and feasibility). Furthermore, the WEI is improved to reflect the preferences of the residents with regard to management objectives through weights (of PFD, PSD, and PWQD) obtained from questionaires of residents. Finally, this study derives a procedure to identify the spatial investment prioritization using four indices.     

Correction to: Future Hydrological Drought Analysis Considering Agricultural Water Withdrawal Under SSP Scenarios

Water Resources Management -     

Integrated Use of a Continuous Simulation Model and Multi-Attribute Decision-Making for Ranking Urban Watershed Management Alternatives

The objective of this paper is to introduce a continuous simulation-based screening procedure for ranking urban watershed management alternatives using multi-attribute decision making (MADM). The procedure integrates continuous urban runoff simulation results from the United States Environmental Protection Agency’s Storm Water Management Model (SWMM) with the use of an alternative evaluation index (AEI) and MADM techniques, following the driver-pressure-state-impact-response (DPSIR) approach. The analytic hierarchy process estimates the weights of the criteria, and SWMM results are used to quantify the effects of the management alternatives on water quantity and quality metrics. In addition, the tendency of AEI to reflect resident preferences toward management objectives is incorporated to include stakeholder participation in the decision-making process. This systematic decision support process is demonstrated for a Korean urban watershed. According to the AEI, seven alternatives were divided into three groups: poor (0∼0.3), acceptable (0.3∼0.6), and good (0.6∼1). The use of multiple MADM techniques provided a consistency check. The demonstration illustrates the ability of the continuous simulation-based MADM approach to provide decision makers with a ranking of suitable urban watershed management alternatives which incorporate stakeholder feedback.     

High-performance IoT streaming data prediction system using Spark: a case study of air pollution

Neural Computing and Applications - Internet-of-Things (IoT) devices are becoming prevalent, and some of them, such as sensors, generate continuous time-series data, i.e., streaming data. These IoT...     

Enhancement of Thermoelectric Figure of Merit for Bi0.5Sb1.5Te3 by Metal Nanoparticle Decoration

Introducing nanoinclusions in thermoelectric (TE) materials is expected to lower the lattice thermal conductivity by intensifying the phonon scattering effect, thus enhancing their TE figure of merit ZT. We report a novel method of fabricating Bi_0.5Sb_1.5Te₃ nanocomposite with nanoscale metal particles by using metal acetate precursor, which is low cost and facile to scale up for mass production. Ag and Cu particles of ??40?nm were successfully near-monodispersed at grain boundaries of Bi_0.5Sb_1.5Te₃ matrix. The well-dispersed metal nanoparticles reduce the lattice thermal conductivity extensively, while enhancing the power factor. Consequently, ZT was enhanced by more than 25% near room temperature and by more than 300% at 520?K compared with a Bi_0.5Sb_1.5Te₃ reference sample. The peak ZT of 1.35 was achieved at 400?K for 0.1?wt.% Cu-decorated Bi_0.5Sb_1.5Te₃.     

A fuzzy multi-criteria approach to flood risk vulnerability in South Korea by considering climate change impacts

This study develops a framework to quantify the flood risk vulnerability in South Korea by considering climate change impacts. On the basis of the concept of exposure-sensitivity-adaptive capacity, 21 proxy variables are selected and screened, and their weights are determined for their objectivity by using the Delphi technique. The data from 16 provinces of South Korea and the weighting values of all proxy variables are fuzzified to consider uncertainty. In addition, the National Center for Atmosphere Research Community Climate System Model 3 (CCSM3) in conjunction with the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenario (SRES) A1B, A2, B1, A1T, A1FI, and B2 are used for future climate data (2020s, 2050s, and 2080s). Therefore, 19 flood risk vulnerabilities of South Korea, including present conditions, are quantitatively evaluated and compared. Three Multi-Criteria Decision Making (MCDM) techniques – Weighted Sum Method (WSM), Technique for Order Preference by Similarity to Ideal Situation (TOPSIS), and fuzzy TOPSIS – are used to quantify all spatial vulnerabilities. As a result, some fuzzy TOPSIS rankings are quite different to those of WSM and TOPSIS, and the ranking patterns of the 19 climate change scenarios are also derived in a dissimilar way. In addition, if the variances of the provinces’ rankings are considered, some provinces showing low values can plan their climate change adaptation strategies by taking into consideration their relatively certain rankings. In the end, the vulnerability assessment for climate change should consider not only various MCDM techniques but also the uncertainty of weighting values and proxy variable data.     

Prioritizing Feasible Locations for Permeable Pavement Using MODFLOW and Multi-criteria Decision Making Methods

Water Resources Management - This study provides a systematic three-step approach to prioritizing feasible locations for permeable pavement, taking into account environmental, economic, and social...     

Enhanced Thermal Conductivity of Polymer Matrix Composite via High Solids Loading of Aluminum Nitride in Epoxy Resin

Most semiconductor devices are now packaged in an epoxy polymer composite, which includes silica powder filler for reducing the thermal expansion coefficient. However, increased heat output from near-future semiconductors will require higher thermal conductivity fillers such as aluminum nitride (AlN) powder, instead of silica. Dispersant chemistry is applied, in order to achieve a high volume percentage of AlN powder in epoxy without causing excessive viscosity before the epoxy monomer is crosslinked, thereby increasing the thermal conductivity of the composite. In the preliminary experiment, high solids loading, up to 57 vol%, was achieved with a wide particle size distribution, and the viscosity of that dispersion was 60 000 to 90 000 cps, resulting in easy flow by gravity alone at room temperature. The highest thermal conductivity of the composites measured by the hot-disk method was 3.39 W/mK, which is approximately 15 times higher than pure epoxy. The Agari and Uno model was a good fit to the experimental data. Electronic I – V curves obtained after encapsulation of testing devices indicated that the highly AlN-filled epoxy slip appeared to be feasible for use in the encapsulation of integrated circuit chips.     

CO2/CH4 separation using inside coated thin film composite hollow fiber membranes prepared by interfacial polymerization

Carbon dioxide(CO_2) is greenhouse gas which originates primarily as a main combustion product of biogas and landfill gas. To separate this gas, an inside coated thin film composite(TFC) hollow fiber membrane was developed by interfacial polymerization between 1,3–cyclohexanebis–methylamine(CHMA) and trimesoyl chloride(TMC). ATR-FTIR, SEM and AFM were used to characterize the active thin layer formed inside the PSf hollow fiber. The separation behavior of the CHMA-TMC/PSf membrane was scrutinized by studying various effects like feed gas pressure and temperature. Furthermore, the influence of CHMA concentration and TMC concentration on membrane morphology and performance were investigated. As a result, it was found that mutually the CHMA concentration and TMC concentration play key roles in determining membrane morphology and performance. Moreover, the CHMA-TMC/PSf composite membrane showed good CO_2/CH_4 separation performance. For CO_2/CH_4 mixture gas(30/70 by volume) test, the membrane(PD1 prepared by CHMA 1.0% and TMC 0.5%) showed a CO_2 permeance of 25 GPU and the best CO_2/CH_4 selectivity of 28 at stage cut of 0.1. The high CO_2/CH_4 separation performance of CHMA-TMC/PSf thin film composite membrane was mostly accredited to the thin film thickness and the properties of binary amino groups.