• Energy Research
• Chinese Academy of Sciences close

Abstract Although the “resource curse” hypothesis has been supported by many empirical studies focusing on the transnational and regional levels, there has always been a point of contention about the proper method of estimating and selecting natural resource indicators in literature. This paper proposes a mixed estimation method for panel data of 10 typical oil and gas resource-based cities in China from 1998 to 2015. The results show that resource industry agglomeration can mirror the distribution and dependence on the resource industry by location rather than by merely measuring the influence of the relative scale of resource extraction on economic growth. Using resource industry agglomeration as the main explanatory variable for regional economic growth verifies the resource curse hypothesis and shows the nonlinear characteristics of the negative correlation between resources and economic growth. Despite mostly similar indicator parameter estimates, marked differences exist in measured effects for material capital investments and technological innovation investments. The result of using resource industry agglomeration as the main explanatory variable is basically consistent with the economic theory and is more in line with observed reality than the alternative indicator. The research conclusions can provide evidence and data for index selection in the studies on the mediating effect of resource curse transmission and international comparison.

Abstract In this paper, the concept of well array operating enhanced geothermal system (EGS) is proposed in response to the existing challenges in EGS commercialization. A well array operating EGS is characterized by well sharing, which substantially reduces drilling cost and maximizes mass flow rate. Following a thorough discussion of conditions for representing an EGS by a 2D model, the life time performance of a well array operating EGS is investigated based on 2D finite element modeling. The accuracy of the presented numerical results is quantified by systematic tests of mesh, element order and time step dependence, and by direct comparison with an analytical solution for 2D porous flow, which is derived in the paper as well. This paper demonstrates that 2D modeling is not only capable of accurately solving a wide range of EGS problems at low computational cost, but also a powerful tool for quantitatively estimating 3D numerical modeling errors, which are usually not adequately addressed in previous studies. The modeling results of the well array operating EGS presented in this paper may serve as a benchmark for testing future EGS models.

Abstract Biomass, as a renewable and sustainable energy resource, can be converted into environmentally friendly and practically valuable biofuels and chemical materials via pyrolysis. However, the process optimization and pyrolysis efficiency are restricted by the limited perception of the complicated mechanisms and kinetics for biomass pyrolysis. Here, to establish an in-depth mechanism model for biomass pyrolysis, we presented a novel investigation for the thermal evolutions and pyrolysis kinetics of the functional groups in peanut shell matrix by using in-situ Fourier transform infrared spectrometry (in-situ FTIR) and thermogravimetric analysis-Fourier transform infrared spectrometry-mass spectrometry (TG-FTIR-MS). The in-situ FTIR spectrum deconvolution for the solid matrix was innovatively introduced to identify and quantify the real-time evolution and thermal dynamics of the functional groups during peanut shell pyrolysis. The result for the first time proposed that the pyrolysis mechanisms of total OH at 20–380 °C, aliphatic C-Hn groups at 20–500 °C, C O groups at 260–500 °C, and C–O groups at 300–500 °C were dominant by diffusion and order-based chemical reactions. The TG-FTIR-MS analysis was conducted for the online monitoring of the released volatiles and gases, the amounts of which were in the sequence of C O > CO2 > aliphatic C–O-(H) > C–O-(C) in esters > aromatics > H2O > phenolic hydroxyl > aliphatic hydrocarbons > CO. The study established a novel methodology to evaluate the biomass pyrolysis mechanisms at the molecular level, which provided valuable information for developing advanced pyrolysis techniques on a large scale for sustainable ecosystem.

AbstractAlthough the process of microbial degradation of coal to produce biomethane has got much attention from many research works, the products profiles of coal at the initial stage of methanogenic bioconversion are not clear yet. In this study, five coal‐degrading bacterial strains (CD1, CD10, CD20, CD24, and CD25) from a methanogenic community were isolated and identified. Among them, CD1 and CD24 belong to Paenibacillus sp., CD10 and CD20 belong to Bacillus sp., and CD25 belongs to Stenotrophomonas sp. After biotreatment of lignite and bituminous coal, the kinds of newly produced compounds were 33 and 45, respectively. Metabolomics analysis showed that a large number of alkane compounds and heterocyclic aromatic compounds were produced after degradation of bituminous coal and lignite by isolated bacteria, and most of the compounds had been produced in a hydroxylated or acylated manner, indicating that the initial microbial treatment enhanced the bioavailability of coal. Some alkaloids and biosurfactants were also detected in the aforementioned products, such as glycerophosphocholine, proveratrol A, proveratrol B, surfactin, etc. These microbial metabolites may play an important role in solubilization during the degradation of coal. This study added to the understanding of the complicated metabolic process of methanogenic coal bioconversion and enabled effective production of biomethane with appropriate metabolic strategies.

Abstract This study conducted an experimental investigation on a CO2 transcritical refrigeration system with dual rotor and intermediate cooling compressor (ICC) for automobiles. Based on the typical operating conditions, the performance of the system with ICC was analyzed by comparison with the basic cycle. The results show that the performance of the system with ICC is roughly equivalent to that of the basic cycle under the condition of 35 °C ambient temperature, while it has outstanding superiority under the condition of 45 °C, with 19.8% increment in the maximum cooling capacity and 12.8% increment in the maximum COP, respectively. The effect of the system’s dynamic components on the immediate cooing is analyzed. According to the analysis of experimental data, it is figured out that the trend of the cooling capacity is consistent with the change trend of the inlet temperature of electronic expansion valve (EEV) and there exists an inflection point with adjustment of EEV.

Abstract Fabricating flexible vanadium dioxide (VO2) films is a serious challenge towards commercial applications. In this work, we proposed a new strategy to directly deposit VO2 thermochromic films on flexible substrates by using Cr2O3 structural template layer, which can serve as growth template for low temperature (~300 °C) deposition of VO2 films. The obtained crystalline VO2 films on flexible substrates show significant phase transition properties with narrow hysteresis loops. Optical and electrical characterizations have indicated phase transition features of the flexible VO2 films, with an excellent solar modulation ability (~60% at 2500 nm) and a resistivity change over 2 orders of magnitude. Meanwhile, the flexible VO2 film exhibits narrow hysteresis loops during the phase transition process, and the hysteresis loop widths are less than 1 °C. Flexibility and stability of VO2 film in this work has been demonstrated by a designed bending test, which can maintain stable thermochromic performance after over 5000 bending cycles. This work provided a facile strategy to fabricate VO2 films on flexible substrates as flexible electronic devices.

A multi-channel scan measurement instrument designed for characterizing the infrared obscuring performance of smoke screen at the wavelength of 10.6 µm is developed. It offers 1 to 5 sensors for multi points real time measurements of infrared transmissivity in the field. Data transmission is accomplished by wireless communication. The maximum detection range of the instrument is 500 meters with measurement accuracy better than ± 5%.

In order to provide reference for formulating the effective policies of climate change, we selected Ganan Plateau located in the eastern margin of Qinghai-Tibet Plateau as the study area, and used the farmer's investigation data to analyze the impact of the farmers' perception of climate change on their adaptation indention. The results showed that the farmer's severity perception of climate change declined from the pure agriculture household to the household with combined occupation, and to the non-agriculture household, but the farmer's adaptation efficacy perception was vice versa. Moreover, all of the perceived probability, self-efficacy and adaptation cost of the household with combined occupation were highest, those of the non-agriculture household were the second place and those of the pure agriculture household were the lowest. The farmer's positive adaptation indention of climate change increased from the pure agriculture household to the household with combined occupation, and to the non-agriculture household. Increasing the perceived risk and adaptation efficacy would promote the farmer's positive adaptation intention, but increasing the perceived adaptation cost would promote the farmers' passive adaptation intention. Meanwhile, the more the farmer's agricultural acreage, livestock, income and optimistic degree were, the stronger the farmer's positive adaptation intention was; But the more the farmers' fixed capital, unpaid cash assistance opportunities, relative number and the number of people offering help were, the weaker the farmers' positive adaptation intention was. Finally, we pointed out the measures of promoting the positive adaptation intention and the problems on which we should focus in the future research.

The first decade of the new millennium saw a boom in rubber prices. This led to rapid and widespread land conversion to monoculture rubber plantations in continental SE Asia, where natural rubber production has increased >50% since 2000. Here, we analyze the subsequent spread of rubber between 2005 and 2010 in combination with environmental data and reports on rubber plantation performance. We show that rubber has been planted into increasingly sub-optimal environments. Currently, 72% of plantation area is in environmentally marginal zones where reduced yields are likely. An estimated 57% of the area is susceptible to insufficient water availability, erosion, frost, or wind damage, all of which may make long-term rubber production unsustainable. In 2013 typhoons destroyed plantations worth US$ >250 million in Vietnam alone, and future climate change is likely to lead to a net exacerbation of environmental marginality for both current and predicted future rubber plantation area. New rubber plantations are also frequently placed on lands that are important for biodiversity conservation and ecological functions. For example, between 2005 and 2010 >2500 km(2) of natural tree cover and 610 km(2) of protected areas were converted to plantations. Overall, expansion into marginal areas creates potential for loss-loss scenarios: clearing of high-biodiversity value land for economically unsustainable plantations that are poorly adapted to local conditions and alter landscape functions (e.g. hydrology, erosion) - ultimately compromising livelihoods, particularly when rubber prices fall. (C) 2015 Elsevier Ltd. All rights reserved.