This paper uses the EMF27 scenarios to explore the role of renewable energy (RE) in climate change mitigation. Currently RE supplies almost 20 % of global electricity demand. Almost all EMF27 mitigation scenarios show a strong increase in renewable power production, with a substantial ramp-up of wind and solar power deployment. In many scenarios, renewables are the most important long-term mitigation option for power supply. Wind energy is competitive even without climate policy, whereas the prospects of solar photovoltaics (PV) are highly contingent on the ambitiousness of climate policy. Bioenergy is an important and versatile energy carrier; however—with the exception of low temperature heat—there is less scope for renewables other than biomass for non-electric energy supply. Despite the important role of wind and solar power in climate change mitigation scenarios with full technology availability, limiting their deployment has a relatively small effect on mitigation costs, if nuclear and carbon capture and storage (CCS)—which can serve as substitutes in low-carbon power supply—are available. Limited bioenergy availability in combination with limited wind and solar power by contrast, results in a more substantial increase in mitigation costs. While a number of robust insights emerge, the results on renewable energy deployment levels vary considerably across the models. An in-depth analysis of a subset of EMF27 reveals substantial differences in modeling approaches and parameter assumptions. To a certain degree, differences in model results can be attributed to different assumptions about technology costs, resource potentials and systems integration. 相似文献
We have examined the quality of the National Research Institute for Earth Science and Disaster Prevention (NIED) seismic moment tensor (MT) catalogue obtained using a regional broadband seismic network (FREESIA). First, we examined using synthetic waveforms the robustness of the solutions with regard to data noise as well as to errors in the velocity structure and focal location. Then, to estimate the reliability, robustness and validity of the catalogue, we compared it with the Harvard centroid moment tensor (CMT) catalogue as well as the Japan Meteorological Agency (JMA) focal mechanism catalogue. We found out that the NIED catalogue is consistent with Harvard and JMA catalogues within the uncertainty of 0.1 in moment magnitude, 10 km in depth, and 15° in direction of the stress axes. The NIED MT catalogue succeeded in reducing to 3.5 the lower limit of moment magnitude above which the moment tensor could be reliably estimated. Finally, we estimated the stress tensors in several different regions by using the NIED MT catalogue. This enables us to elucidate the stress/deformation field in and around the Japanese islands to understand the mode of deformation and applied stress. Moreover, we identified a region of abnormal stress in a swarm area from stress tensor estimates. 相似文献
Microbially induced calcium carbonate (CaCO3) precipitation (MICP) has been extensively studied for soil improvement in geotechnical engineering. The quantity and size of calcium carbonate crystals affect the strength of MICP-treated soil. In this study, microfluidic chip experiments and soil column experiments were conducted to optimize MICP treatment protocols for effective strength enhancement of MICP-treated sandy soils. The microscale experiments reveal that, due to Ostwald ripening, longer injection intervals allow crystals to dissolve and reprecipitate into larger crystals regardless of the concentration of cementation solution. Even though a cementation solution input rate of 0.042 mol/l/h is sufficient to maintain a high chemical transformation efficiency, a further reduction in the input rate by about four times resulted in an increase in the size of crystals produced by the end of treatment from about 40 to 60 μm. These findings were applied in soil column experiments. Results showed that significantly larger crystals and higher soil strength were achieved when the normalized rate of cementation solution injection was reduced from 0.042 to 0.021 mol/l/h. Crystal size and soil strength increased slightly more when the normalized input rate was further reduced from 0.021 to 0.010 mol/l/h. This study demonstrates how data from microscale microfluidic experiments that examine the effects of injection intervals and concentration of cementation solution on the properties of calcium carbonate crystals can be used to optimize MICP treatment in macroscale sand soil column experiments for effective strength enhancement.
Fracture zones and their connectivity in geologic media are of great importance to ground water resources management as well as ground water contamination prevention and remediation. In this paper, we applied a recently developed hydraulic tomography (HT) technique and an analysis algorithm (sequential successive linear estimator) to synthetic fractured media. The application aims to explore the potential utility of the technique and the algorithm for characterizing fracture zone distribution and their connectivity. Results of this investigation showed that using HT with a limited number of wells, the fracture zone distribution and its connectivity (general pattern) can be mapped satisfactorily although estimated hydraulic property fields are smooth. As the number of wells and monitoring ports increases, the fracture zone distribution and connectivity become vivid and the estimated hydraulic properties approach true values. We hope that the success of this application may promote the development and application of the new generations of technology (i.e., hydraulic, tracer, pneumatic tomographic surveys) for mapping fractures and other features in geologic media. 相似文献
Under hypothetical and idealized conditions, the horizontal site amplification factor (HSAF) is defined as the ratio of the horizontal Fourier amplitude spectrum (FAS) at a point on the Earth's surface with respect to the horizontal FAS at the identical location but on the outcropping seismological bedrock. The HSAF reflects the profile of local sedimentary soils and weathered rock formations, indicating site effects. In most cases, such an idealized HSAF is difficult to measure directly. Thus, quantitatively estimating a HSAF value is a crucial task in strong-motion prediction over the last century. Fortunately, many strong-motion stations have been constructed throughout Japan, facilitating the characterization of HSAFs down to seismological bedrock at more than 1600 observational sites by the generalized inversion technique (GIT). First, this study reported the similarity distribution of the HSAF and the horizontal-to-vertical spectral ratio of earthquakes (HVSRE). Subsequently, we proposed a hybrid method from a novel aspect for estimating HSAF in terms of the observed similarity distribution and the vertical amplification correction function (VACF) proposed previously. Compared with the direct use of HVSRE for substituting HSAF, the hybrid method proposed herein demonstrated an improvement of greater than 30% in terms of the residuals between estimated HSAFs and those separated from observations. 相似文献
Abstract. There have been two primary sources for industrial indium; one from massive sulfides, while the other is dissemination-veins and skarns, related to felsic igneous rocks. The latter group of the In-bearing deposits is abundant in the Japanese Islands. Indium occurs as In-minerals such as sakuraiite, roquesite, laforetite and many unidentified minerals, but the majority is contained as an impurity in sphalerite, and tin and copper sulfides. Average grades of the ores from which indium has been extracted vary from a few ppm (e.g., Kosaka mine) to more than 300 ppm (Toyoha mine). The amount of indium in all the major basemetal deposits is estimated by analyzing representative samples. The main indium deposits are subvolcanic and tin-poly-metallic vein types. The largest one is Toyoha mine (4,700 tons hi) and the Ashio mine (ca. 1,200 tons In) was found to be the second largest. Many small occurrences, were recognized in the Miocene magnetite-series belt, besides the classic occurrences in the ilmenite-series granitic terrains of SW Japan, including the Ikuno and Akenobe tin(-tungsten) polymetallic veins, located in the northern margin of the late Cretaceous Sanyo ilmenite-series province. Magnetite-series magmas with deep source are necessary to concentrate sulfur in the magma chamber but sedimentary source rocks and their reducing agents are needed to collect and to precipitate indium. The Japanese islands are essentially accretionary terrains intruded by various deep oxidized magmas; thus forming magnetite/ilmenite-series paired belts, which are sometimes mixed. This unique geologic setting may be the most fundamental reason why indium is rich in vein-type deposits of the Japanese Island arcs. 相似文献
This paper evaluated the impacts of climate change mitigation technology options on CO2 emission reductions and the effects of model representations regarding renewable intermittency on the assessment of reduction by using a world energy systems model. First, different diffusion scenarios for carbon dioxide capture and storage (CCS), nuclear power, and wind power and solar PV are selected from EMF27 scenarios to analyze their impacts on CO2 emission reductions. These technologies are important for reducing CO2 intensity of electricity, and the impacts of their diffusion levels on mitigation costs are significant, according to the analyses. Availability of CCS in particular, among the three kinds of technologies, has a large impact on the marginal CO2 abatement cost. In order to analyze effects of model representations regarding renewables intermittency, four different representations are assumed within the model. A simplistic model representation that does not take into consideration the intermittency of wind power and solar PV evaluates larger contributions of the energy sources than those evaluated by a model representation that takes intermittency into consideration. Appropriate consideration of renewables intermittency within global energy systems models will be important for realistic evaluations of climate change mitigation scenarios. 相似文献
Abstract In situ observations of the zircon-reidite transition in ZrSiO4 were carried out using a multianvil high-pressure apparatus and synchrotron radiation. The phase boundary between zircon and reidite was determined to be P (GPa) = 8.5+0.0017×(T-1200) (K) for temperatures between 1100–1900 K. When subducted slabs, including igneous rocks and sediments, descend into the upper mantle, the zircon in the subducted slab transforms into reidite at pressures of about 9 GPa, corresponding to a depth of 270 km. Reidite found in an upper Eocene impact ejecta layer in marine sediments is thought to have been transformed from zircon by a shock event. The peak pressure generated by the shock event in this occurrence is estimated to be higher than 8 GPa.Editorial responsibility: J. Hoefs 相似文献