Dual functional application of pomelo peel-derived bio-based carbon with controllable morphologies: An efficient catalyst for triiodide reduction and accelerant for anaerobic digestion

Pomelo peel-derived bio-based carbon with controllable morphologies are successfully prepared by three different methods (microwave pyrolysis, two-step activation, hydrothermal carbonization combining chemical activation). The differences in specific surface area and pore size distribution caused by various morphology features remarkably affect the application potential of as-prepared bio-based carbon. Two-step activation carbonization is proven to be an effective and feasible method to synthesize small-size bio-based carbon with large specific surface area (1377.60 m²/g) and total pore volume (0.72 m³/g) as compared with other methods. The bio-based carbon prepared by two-step activation method as counter electrode catalyst in dye-sensitized solar cell (DSSC) obtains an excellent photovoltaic performance as compared with the Pt-based DSSC (6.94% vs. 6.71%). Furthermore, the as-prepared bio-based carbon is used as accelerant in anaerobic digestion (AD) systems and obtains the enhanced cumulative biogas production (525 mL/g VS) and chemical oxygen demand removal rate (70.95%) as compared with the control check group (296 mL/g VS, 29.55%). This work illustrates three promising methods to prepare bio-based carbon with controllable morphologies and superior surface area for realizing their multifunction resource utilizations in renewable energy fields.     

Hydrogen production from acidogenic food waste fermentation using untreated inoculum: Effect of substrate concentrations

The effect of substrate concentrations (0, 7.5, 15, 22.5, 30, and 37.5 g-VS/L) on hydrogen production from heat-treated and fresh food waste (FW) using untreated inoculums was investigated in this work. The highest hydrogen yield (75.3 mL/g-VS) was obtained with heat-treated FW at 15 g-VS/L. Lower substrate content could not provide enough organic matter for hydrogen fermentation, while higher substrate concentrations shifted the metabolic pathways from hydrogen fermentation to lactic acid fermentation by enriching the lactic acid bacteria (LAB), which lowered the slurry pH and decreased enzyme activity, resulting in a lower chemical oxygen demand (COD), volatile solid (VS), carbohydrate removal rate, and hydrogen yield. Compared with fresh FW, heat-treated FW is preferred for biohydrogen process with acetate as the main organic product. Additionally, at the optimal concentration (15 g-VS/L) using fresh FW, lactic acid is first accumulated and then degraded to produce hydrogen with butyrate as the main metabolite.     

SWATShare – A web platform for collaborative research and education through online sharing,simulation and visualization of SWAT models

Hydrologic models for a particular watershed or a region are created for addressing a specific research or management problem, and most of the models do not get reused after the project is completed. Similarly, multiple models may exist for a particular geographic location from different researchers or organizations. To avoid the duplication of efforts, and enable model reuse and enhancement through collaborative efforts, a prototype cyberinfrastructure, called SWATShare, is developed for sharing, execution and visualization of Soil and Water Assessment Tool (SWAT). The objective of this paper is to present the software architecture, functional capabilities and implementation of SWATShare as a collaborative environment for hydrology research and education using the models published and shared in the system. Besides the capability of publishing, sharing, discovery and downloading of SWAT models, some of the functions in SWATShare such as model calibration are supported by providing access to high performance computing resources including the XSEDE and cloud. Additionally, SWATShare can create dynamic spatial and temporal plots of model outputs at different scales. SWATShare can also be used as an educational tool within a classroom setting for comparing the hydrologic processes under different geographic and climatic settings. The utility of SWATShare for collaborative research and education is demonstrated by using three case studies. Even though this paper focuses on the SWAT model, the system’s architecture can be replicated for other models as well.     

改进的属性综合评价模型在旱情评价中的应用

在区域干旱评价指标体系及其评价标准建立的基础上,在遵循"一次一分"属性统计原则的前提下,结合集对分析的思想,构造了一种更符合人们认识习惯的"宽域式"单指标性能函数,并用基于加速遗传算法改进的模糊层次分析法确定各评价指标的权重,从而建立了基于集对分析理论的属性综合评价模型。模型在山东省1972年-2003年干旱等级评价中的应用结果表明,该模型的计算过程直观简便,结果合理,具有推广应用价值。     

A novel method for increasing biohydrogen production from food waste using electrodialysis

The impact of continuous removal of volatile fatty acids on fermentative hydrogen production from food waste (FW) in a Continuously Stirred Tank Reactor (CSTR) was evaluated. Two experimental phases were conducted, a control phase and one in which volatile fatty acids were removed continuously from the reactor for the first time by electrodialysis (ED). Hydrogen yields were 64.7 cm³ H₂/g VS and 227.3 cm³ H₂/g VS for control phase, and ED phase respectively. Continuous removal of volatile fatty acids during fermentation not only increased H₂ yields but increased the production of volatile fatty acids (a valuable chemical feedstock) from 0.14 g/g VS to 0.34 g/g VS_.     

The Gays River mine tailing revegetation study

The Gays River (NS) lead-zinc mine ceased operations in 1982. Seven ha of calcereous mine tailings were left which required stabilization. The tailings, variable in physical composition with depth, were devoid of organic matter, N and P. A potting experiment using the tailings, with and without fertilizer, established 6 plant species which could potentially revegetate the tailing site. Experimental plots (24) were established on the tailings in May 1983 using the same 6 species and 2 indigenous species (alder (Alnus rugosa) and bulbrush (Scirpus americanus Pers.)). The plots were maintained through June 1985; plant yield and tissue analysis for macro- and micronutrients followed each cutting or sampling data. The final recommendations for reclamation were to drill in alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) seeds, cut and fertilize annually with 800 kg ha^-1 of 12-24-24 or transplant couchgrass (Agropyron repens) and fertilize periodically with 12-24-24.     

Prediction of extreme precipitation using a neural network: application to summer flood occurrence in Moravia

Dramatic floods occurred in Central Europe in summer 1997, and Czech Republic has been seriously affected in its eastern part—Moravia. A predictive approach based on modelling flood recurrence may be helpful in flood management. Summer floods are typically characterized by saturated catchment due to long-lasting heavy precipitation followed by a sudden extreme rainfall. In present work an artificial neural network (ANN) model was evaluated for precipitation forecasting. Back propagation neural networks were trained with actual monthly precipitation data from two Moravian meteorological stations for a time period of 38 years. Predicted amounts are of next-month-precipitation and summer precipitation in the next year. The ANN models provided a good fit with the actual data, and have shown a high feasibility in prediction of extreme precipitation.     

Simulating the impacts of reduced rainfall on carbon stocks and net ecosystem exchange in a tropical forest

Forest models can be useful tools to improve our understanding of forest dynamics and to evaluate potential impacts of climate change. There is an ongoing debate how drought events influence the dynamics of tropical forests. In this study, we explored the role of changes in precipitation on tropical forests in Madagascar. Therefore, we derived a new parameterization of the process-based forest model FORMIND using local forest inventory measurements. This model was extended by a drought sensitivity module based on a water use efficiency concept.The objective of this study is to evaluate how different levels of water availability modify forest productivity, and net ecosystem exchange as a function of mean annual precipitation. Our simulation results indicate that a moderate precipitation decline (0%–30% of current precipitation conditions) has only minor impact on forest carbon stocks and exchange. A rainfall decline below 30% of current precipitation conditions would change forest structure considerably.     

沣河水质与流量之间的关系分析

为了打造生态沣河,本文基于秦渡镇断面2001-2009年的定期水质监测资料,以及秦渡镇水文站2001年到2009年的逐日流量数据,以及2009年到2011年大峪口断面、秦渡镇断面的多场洪水监测资料,研究分析了沣河水质与流量之间的关系.结果表明:(1)监测断面流量的大小和每场洪水平均流量的大小均对NH3-N、TN和COD的污染浓度有影响,且流域上下游不同断面的水质流量之间的关系也有差异;(2)根据2002年到2008年秦渡镇断面所监测的6场洪水资料,可知洪水对COD非点源污染的影响较大.而2006年NH3-N、TN的点源污染严重,此外几年NH3-N的点源污染较严重,TN变化不稳定.