Economic growth,international trade,and the depletion or conservation of renewable natural resources

Conservation of renewable natural resources and promotion of economic growth are both sustainable development goals. Here, we study the interdependency between economic growth, international trade, and the use of renewable natural resources—under alternative institutional settings of either open access or full property rights—in an endogenous growth model. We find that if the resource is depleted over time, consumption growth is reduced. Economic growth and international trade only impact resource use when the resource is harvested under full property rights. Then, widening international trade can lead countries to shift from conservation to depletion. Changes in the institutional setting of resource use in one country may have repercussions on trading partners. Our results indicate potential trade-offs between the sustainable development goals and imply that policies focusing on resource use or trade (e.g., international trade bans or certified trade) are not sufficient to prevent resource depletion.     

Cost pass-through to higher ethanol blends at the pump: Evidence from Minnesota gas station data

We examine the pass-through of wholesale prices to retail prices in the market for E85, which contains 51%–83% ethanol, and in the much larger market for E10, which contains 10% ethanol. We use a panel dataset consisting of monthly observations from 2007 to March 2015 on wholesale and retail prices for 274 Minnesota gas stations that sell both E10 and E85. Consistent with prior research, the cumulative pass-through coefficient for E10 is 1.00 after one month. In contrast, the E85 market is sparse, and although pass-through increased over time, we estimate it to be only 0.53 statewide from 2012 to 2015. Pass-through is higher at stations with more local E85 competitors. In the Twin Cities, which has a high density of E85 stations, pass-through is nearly complete, but outside the Twin Cities slightly less than half the wholesale discount of E85, relative to E10, is passed on to the consumer.     

CEO education and corporate environmental footprint

We analyze the effect of CEO education on environmental decision-making. Using a unique sample of Danish firms from 1996 to 2012, we find that CEO education significantly improves firms' energy efficiency. We seek to derive causality using health shocks: the hospitalization of highly educated CEOs induces a drop in energy efficiency, whereas the hospitalization of less educated CEOs does not have any significant effect. Exploring the mechanisms at play, we show that our results are largely driven by advanced education in business degrees. Moreover, we show that CEO education is associated with greater environmental awareness: highly educated CEOs exhibit greater concerns for climate change, as measured by a survey of social preferences, and drive more environmentally efficient cars. Taken together, our findings suggest that education shapes managerial styles giving rise to greater sustainability in corporate actions.     

Can climate mitigation help the poor? Measuring impacts of the CDM in rural China

This study examines whether investment in climate change mitigation contributes to poverty alleviation. We investigate the impacts of the renewable energy-based clean development mechanism (RE-CDM) projects on rural communities in China. The impacts of RE-CDM projects are estimated by combining propensity score matching with the difference-in-differences approach. We found that the biomass-based CDM projects significantly contribute to income improvement and employment generation in rural communities in China. Our estimation results also reveal that wind energy-based CDM projects have the potential to increase income and the share of labor force in the primary industry in rural areas. These results suggest different channels through which renewable energy sources affect income.     

A new baseline model for estimating willingness to pay from discrete choice models

We show a substantive problem exists with the widely-used ratio of coefficients approach to calculating willingness to pay (WTP) from discrete choice models. The correctly calculated standard error for WTP using this approach is shown to be undefined. This occurs because the cost parameter's standard error implies some possibility the true parameter value is arbitrarily close to zero. We propose a simple yet elegant way to overcome this problem by reparameterizing the (negative) cost variable's coefficient using an exponential transformation to enforce the theoretically correct positive coefficient. With it the confidence interval for WTP is now finite and well behaved.     

Experimental and CFD-DEM study of the dispersion and combustion of wheat starch and carbon-black particles during the standard 20L sphere test

The 20L sphere is one of the standard devices used for dust explosivity characterization. One concern about the effectiveness and reliability of this test is related to the particle size variation due to particles' agglomeration and de-agglomeration. These phenomena are related to the turbulent regime of the dust cloud during the dispersion. This variable must be considered since it determines the uncertainty level of the ignitability and severity parameters of dust combustion. In this context, this study describes the influence of the cloud turbulence on the dust segregation and fragmentation through a study combining both, experimental and computational approaches. The behavior of the gas-solid mixture evidenced with the standard rebound nozzle was compared with that observed with six new nozzle geometries. Thereafter, the time-variation of the Particle Size Distribution (PSD) within the 20L sphere was analyzed for two different powders: carbon-black and wheat starch. On the one hand, the turbulence levels and PSD variations were characterized by Particle Image Velocimetry (PIV) tests and granulometric analyses, respectively. On the other hand, a computational approach described the dispersion process with CFD-DEM simulations developed in STAR-CCM + v11.04.010. The simulation results established that the homogeneity assumption is not satisfied with the nozzles studied. Nonetheless, the particles segregation levels can be reduced using nozzles that generate a better dust distribution in the gas-solid injections. Subsequently, an additional first-approach CFD model was established to study the behavior of the combustion step for a starch/air mixture. This model considers the gas-phase reactions of the combustible gases that are produced from the devolatilization of wheat starch ($CO,C{H}_4,C_2{H}_4,C_2{H}_6,C_2{H}_2,$ and $H_2$) and allowed to establish the approximate fraction of the particle mass that devolatilizes, as well as to confirm that the modeling of the pyrolysis stage is essential for the correct prediction of the maximum rate of pressure rise.     

Environmental occurrence of Q1, a C9H3C17N2 compound,that has been identified as a natural bioaccumulative organochlorine

Environmental appearance of Q1, a natural heptachloro compound with the molecular formula C₉H₃Cl₇N₂, was studied in samples from different sites all over the world. Q1 was expected to have a bipyrrole backbone, similar to other compounds ascribed to natural sources. A method for isolation of Q1 was developed by combination of adsorption chromatography on silica and normal phase HPLC with an amino phase. UV-detection of Q1 supports the aromatic character of the compound.

The high levels detected in samples of marine mammals and birds suggested that Q1 is both a persistent and a bioaccumulative contaminant. This was underscored by calculated log K_OW in the range of other lipophilic organohalogens. In accordance with earlier studies, highest Q1 concentrations were found in the Southern Hemisphere, but with a highly selective GC/ECNI-MS-SIM method, detection of Q1 was also achieved in many samples from the Northern Hemisphere. In addition to marine mammals and birds, Q1 was also detected in fish from the Mediterranean Sea and the Antarctic. Traces were also detected in SRM 1588 certified cod liver oil, but Q1 was not detected in fish from Hong Kong and Lake Baikal.     

2014年北京市PM2.5质量浓度分析及比对研究

本研究选择污染严重的北京作为研究区域,自2013年12月起至2014年12月,通过设在北五环中国环境科学研究院(CRAES)内的定点监测,获得375天有效平行样品(T和Q)。统计结果表明,2014年北京市PM_(2.5)质量浓度从优良水平的6.9μg/m~3到极重污染的422.1μg/m~3,年均浓度值在100μg/m~3左右。T组和Q组线性相关,但T/Q并非定值,冬季最高,R~2=0.974,对应T/Q=1.014,可能由于冬季污染程度较重,滤膜性能差异可忽略。除春季外,其它三季的PM_(2.5)都是T组>Q组,与石英膜的纤维结构不够致密有关。以T组质量浓度数据为准,与国控监测点奥体中心点公报的日均PM_(2.5)进行比对,结果显示二者基本同步,在春冬季呈现较高的污染浓度,在夏季最低。在严重污染时(PM_(2.5)>250.0μg/m~3),在线监测可能低估PM_(2.5)而T组能更客观地记录实际污染状况。统计2014年全年污染等级分布,4~8月份基本未出现重度污染,而在冬季采暖期10~12月份,优良天数不足50%。综合分析风速、相对湿度对PM_(2.5)质量浓度的影响,证实冬季取暖燃煤和无风、高湿、逆温的静稳天气是霾频发的主要原因。     

Providing the Spark: Impact of financial incentives on battery electric vehicle adoption

To overcome adoption barriers and promote battery electric vehicles (BEVs) as an energy efficient consumer transportation option, a number of states offer subsidies to consumers for BEVs. We use a national data set of vehicle registrations and state-level financial incentives to assess the impact of vehicle purchase subsidies on adoption using both difference-in-differences and synthetic controls methods. We find that incentives offered as direct purchase rebates generate increased levels of new BEV registrations at a rate of approximately 8 percent per thousand dollars of incentive offered. Between 2011 and 2015, vehicle rebate incentives are associated with an increase in overall BEV registrations of approximately 11 percent. Our findings indicate incentives offered as state income tax credits do not have a statistically significant effect on BEV adoptions, though we caution this may be a result of limited temporal variation in BEV incentives across our sample. Responses to rebate incentives do not differ significantly by the make of the vehicle purchased (i.e., Tesla and non-Tesla vehicles). We combine our results with recent assessments of marginal environmental costs of electric vehicle charging and measure net welfare effects of BEV subsidy programs. Our analysis indicates these programs are not welfare-improving if only considering benefits associated with avoided emissions. Additional benefits associated with long-term market growth, production cost savings, network externalities, or accelerated innovation could substantially impact the net welfare outcomes.     

睾丸酮丛毛单胞菌对喹啉类化合物的降解

对喹啉、异喹啉、2-甲基喹啉、3-甲基喹啉、4-甲基喹啉和6-甲基喹啉在睾丸酮丝毛单胞菌(Comamonas testosteroni Q10)作用下的降解及底物之间的相互作用进行研究．结果表明,喹啉和3-甲基喹啉不仅能有效地被降解,而且细菌也有明显的生长,而其它化合物虽有部分降解但没有观察到细胞生长．底物初始浓度的增加对菌Q10有一定抑制作用．喹啉的存在对其它化合物的降解具有不同的促进效应,其中尤以6-甲基喹啉和4-甲基喹啉最为明显．能在较短时间内得到完全去除,而在各二元体系中喹啉的降解受到这些化合物的抑制作用．