Integrated bio-electrogenic process for bioelectricity production and cathodic nutrient recovery from azo dye wastewater

Microbial electrochemical treatment (MET) process was designed to evaluate complete mineralization of partially treated dye effluent obtained from anoxically operated Periodic discontinuous batch reactor (PDBR) for simultaneous bioelectricity generation and recovery of nutrients. In MET bioreactor, anode and cathode chambers were fed with designed synthetic wastewater (DSW) and PDBR dye effluents. The dye metabolite (NH₄⁺) will be converted to nitrates by the activity of aerobic biocatalyst present in cathode chamber to be used as biofertilizer. Dye removal of 90.2% was observed with good electrogenic activity (voltage (OCV)/current; 395 mV/1.77 mA). The mineralization of dye and its intermediates were assessed by reduction in overall toxicity from 23% to 4%. Chemical oxygen demand (COD) removal efficiency of 75% (anode) and 88% (cathode) were observed in correspondence to higher azoreductase (18.7 U; 48 h) and dehydrogenase (1.66 μg/ml of toluene; 24 h) enzyme activities which correlated well with metabolic activities of biocatalyst. Bioelectrocatalytic behavior of mixed biocatalyst on the basis of redox catalytic currents and prevalence of redox mediators signified the specific function of electron transfer toward dye mineralization. The results obtained suggest that the use of MET can considerably degrade toxic pollutants and provides nitrate rich solution (biofertilizer). Utilization of recovered nutrients directly to farms without any energy intensive methods is reported in this communication.     

Oil prices and financial stress: A volatility spillover analysis

This paper examines whether there is a volatility transmission between oil prices and financial stress by means of the volatility spillover test. We employ WTI crude oil prices and Cleveland financial stress index for the period 1991–2014 and divide the sample into pre-crisis, in-crisis, and post-crisis periods due to the downward trend in oil price in 2008. The volatility model estimations indicate that oil prices and financial stress index are dominated by long-run volatility. The volatility spillover causality test supports evidence on risk transfer from oil prices to financial stress before the crisis and from financial stress to oil prices after the crisis. The impulse response analysis shows that the volatility transmission pattern has similar dynamics before and after the crisis and is characterized by higher and long-lived effects during the crisis. Our results have implications for both policy makers and investors, and for future work.     

微细粒煤间断浓缩沉降试验研究

为确定微细粒煤泥高效浓缩的最佳操作参数,提出了一种新方法实现煤泥连续浓缩的预测与优化,借助沉降量筒与澄清水质量浓度测量装置确定一定单位面积处理量下煤泥浓缩沉降最佳药剂添加量、入料质量浓度和流量,并预测出该条件下的浓缩效率。试验结果表明:随着质量浓度的增大,单位质量最佳药剂消耗量增加,微细颗粒等速沉降速度基本不变,单位面积处理量一定的情况下,压缩区高度降低速度ν基本不变;在20.66 g/(dm2·min)单位面积处理量下,入料质量浓度50 g/L,药剂添加量11 mg/L,入料流量0.083 L/min时,可达到最佳浓缩效率89.05%;随着浓缩时间增加,浓缩效率都不断增加并逐渐达到饱和;当单位处理量小时,低质量浓度浓缩效果较好,但处理量较大时,较高质量浓度较低流量配合更具优势。     

Lower electricity prices and greenhouse gas emissions due to rooftop solar: empirical results for Massachusetts

Monthly and hourly correlations among photovoltaic (PV) capacity utilization, electricity prices, electricity consumption, and the thermal efficiency of power plants in Massachusetts reduce electricity prices and carbon emissions beyond average calculations. PV utilization rates are highest when the thermal efficiencies of natural gas fired power plants are lowest, which reduces emissions of CO₂ and CH₄ by 0.3% relative to the annual average emission rate. There is a positive correlation between PV utilization rates and electricity prices, which raises the implied price of PV electricity by up to 10% relative to the annual average price, such that the average MWh reduces electricity prices by $0.26–$1.86 per MWh. These price reductions save Massachusetts rate-payers $184 million between 2010 and 2012. The current and net present values of these savings are greater than the cost of solar renewable energy credits which is the policy instrument that is used to accelerate the installation of PV capacity. Together, these results suggest that rooftop PV is an economically viable source of power in Massachusetts even though it has not reached socket parity.     

An impulse power driver for field emission lighting with variable-frequency control

This study proposes an impulse power driver, which is used to eliminate arcing phenomenon and to maintain lamp luminance for field emission lamp driving. To compact the system configuration and to reduce the system cost, the flyback topology is employed as the main circuit. Next, the phase-locked loop technique is embedded to implement variable-frequency control as a feedback mechanism in this study. With the proposed control mechanism, the peak value of the impulse lamp current can be captured and regulated for stabilizing lamp luminance. Furthermore, the related design considerations are detailed. All the experimental results agree to the theoretical predictions.     

On the asymmetric effects of oil price changes on Alaska oil tax revenue

Alaska depends on oil tax revenue for more than 90% of the state budget. In this article, we apply the nonlinear autoregressive distributed lag (ARDL) approach of to test whether the effect of changes in oil prices on Alaska’s oil reven ues is symmetric or asymmetric. The results show that oil prices have an asymmetric effect on Alaska’s oil revenues in the long run, though not in the short run. Additionally, declines in oil prices have a more substantial long-run effect than increases in oil prices.     

Merit-order effects of renewable energy and price divergence in California’s day-ahead and real-time electricity markets

We answer two policy questions: (1) what are the estimated merit-order effects of renewable energy in the California Independent System Operator’s (CAISO’s) day-ahead market (DAM) and real-time market (RTM)? and (2) what causes the hourly DAM and RTM prices to systematically diverge? The first question is timely and relevant because if the merit-order effect estimates are small, California’s renewable energy development is of limited help in cutting electricity consumers’ bills but also has a lesser adverse impact on the state’s investment incentive for natural-gas-fired generation. The second question is related to the efficient market hypothesis under which the hourly RTM and DAM prices tend to converge. Using a sample of about 21,000 hourly observations of CAISO market prices and their fundamental drivers during 12/12/2012–04/30/2015, we document statistically significant estimates (p-value≤0.01) for the DAM and RTM merit-order effects. This finding lends support to California’s adopted procurement process to provide sufficient investment incentives for natural-gas-fired generation. We document that the RTM-DAM price divergence partly depends on the CASIO’s day-ahead forecast errors for system loads and renewable energy. This finding suggests that improving the performance of the CAISO’s day-ahead forecasts can enhance trading efficiency in California’s DAM and RTM electricity markets.     

Mechanical properties of carbon fiber paper reinforced thermoplastics using mixed discontinuous recycled carbon fibers

Market demand for carbon fiber (CF) increases annually. Therefore, owing to the growing amount of carbon fiber-reinforced plastic (CFRP) waste, CFRP manufacturers are attempting to develop and design materials and products by paying greater attention to ecological and economic factors. In this report, recycled CF (rCF) varieties with differing mechanical properties are mixed to determine the possibility of rCF application in future structural materials. 1, 3, 5, 8 and 10 MPa are investigated for proper compression molding pressure. The range of 5–8 MPa is recommended. Mixing different rCFs can control the mechanical properties of the material, which is valuable for current rCF applications. A modified rule of mixture (ROM) is used to discuss flexural modulus and flexural strength. The coefficients for ROM are given for different rCF.     

China＇s Oil ＆ Gas Industry Overview in 2013 and Outlook for 2014

Overview of development in China＇s oil and gas industry in 2013
China＇s economy grew slowly but steadily, at an expected annual rate of 7.6%, and investment as a contribution towards economic growth increased
In 2013, the economy of China entered a transition period of slow but steady growth, with the annual GDP growth expected to be 7.6%, after a down-and-up swing. Driven by policies ensuring steady growth, investment once again became the main driving force of economic growth.     

岩体非贯通结构面的岩桥贯通准则研究

传统的块体理论分析方法未考虑到非贯通结构面在施工扰动作用下可能出现连通的问题,导致搜索出的关键块体不够精准和全面。如何判断非贯通结构面是否应该连通成为了块体理论研究的一个重要课题。采用数值模拟方法计算岩体试样的贯通强度与峰值强度,并引入贯通系数变量描述贯通强度与峰值强度的比值变化。将贯通强度作为判断岩桥贯通与否的衡量指标,定量分析贯通强度与岩桥倾角、结构面摩擦系数、围压、连通率和结构面倾角之间的函数关系,即含两条非贯通结构面岩体的岩桥贯通准则。该准则可以准确判断含两条非贯通结构面岩体的岩桥是否应该连通。基于岩桥贯通准则的块体理论能够准确搜索出因岩体内部结构面扩展贯通而滑移的关键块体,使得搜索出的关键块体更加全面,更好的分析工程的稳定性。