Heat capacity and entropy of rutile (TiO<Subscript>2</Subscript>) and nepheline (NaAlSiO<Subscript>4</Subscript>)     

D. de Ligny  P. Richet  E. F. Westrum Jr  J. Roux 《Physics and Chemistry of Minerals》2002,29(4):267-272

 From heat capacities measured adiabatically at low temperatures, the standard entropies at 298.15 K of synthetic rutile (TiO₂) and nepheline (NaAlSiO₄) have been determined to be 50.0 ± 0.1 and 122.8 ± 0.3 J mol⁻¹ K, respectively. These values agree with previous measurements and in particular confirm the higher entropy of nepheline with respect to that of the less dense NaAlSiO₄ polymorph carnegieite. Received: 23 July 2001 / Accepted: 12 October 2001  相似文献   

Hierarchical probabilistic regionalization of volcanism for Sengan region,Japan     

Pinnaduwa H. S. W. Kulatilake  Jinyong Park  Pirahas Balasingam  Sean A. Mckenna 《Geotechnical and Geological Engineering》2007,25(1):79-102

A 1 km square regular grid system created on the Universal Transverse Mercator zone 54 projected coordinate system is used to work with volcanism related data for Sengan region. The following geologic variables were determined as the most important for identifying volcanism: geothermal gradient, groundwater temperature, heat discharge, groundwater pH value, presence of volcanic rocks and presence of hydrothermal alteration. Data available for each of these important geologic variables were used to perform directional variogram modeling and kriging to estimate geologic variable vectors at each of the 23949 centers of the chosen 1 km cell grid system. Cluster analysis was performed on the 23949 complete variable vectors to classify each center of 1 km cell into one of five different statistically homogeneous groups with respect to potential volcanism spanning from lowest possible volcanism to highest possible volcanism with increasing group number. A discriminant analysis incorporating Bayes’ theorem was performed to construct maps showing the probability of group membership for each of the volcanism groups. The said maps showed good comparisons with the recorded locations of volcanism within the Sengan region. No volcanic data were found to exist in the group 1 region. The high probability areas within group 1 have the chance of being the no volcanism region. Entropy of classification is calculated to assess the uncertainty of the allocation process of each 1 km cell center location based on the calculated probabilities. The recorded volcanism data are also plotted on the entropy map to examine the uncertainty level of the estimations at the locations where volcanism exists. The volcanic data cell locations that are in the high volcanism regions (groups 4 and 5) showed relatively low mapping estimation uncertainty. On the other hand, the volcanic data cell locations that are in the low volcanism region (group 2) showed relatively high mapping estimation uncertainty. The volcanic data cell locations that are in the medium volcanism region (group 3) showed relatively moderate mapping estimation uncertainty. Areas of high uncertainty provide locations where additional site characterization resources can be spent most effectively. The new data collected can be added to the existing database to perform future regionalized mapping and reduce the uncertainty level of the existing estimations.  相似文献   

Evolution-EM signals before earthquakes in terms of mesomechanics and complexity     

K. Eftaxias  V.E. Panin  Ye.Ye. Deryugin 《Tectonophysics》2007,431(1-4):273

MHz-to-kHz electromagnetic (EM) anomalies have been detected worldwide over time intervals ranging from a few days to a few hours prior to near-surface earthquakes (EQs) that have occurred on land with magnitude approximately six or larger. The MHz radiation systematically appears earlier than the kHz. Laboratory experiments on rock samples reveal a similar change in the frequency content during progressive deformation, i.e. the emissions exhibit a frequency shift from MHz to kHz just before failure of the samples. Herein, we attempt to associate these consecutively emerging MHz and kHz modes of the pre-fracture EM emission with successive distinct stages of the fracture preparation process and the associated fracture mechanisms. We base our approach on synergetic principles of physical mesomechanics. A universal principle of physical mesomechanics is that the plastic deformation of a solid is related to its loss of shear stability at the micro-, meso-, and macroscale levels. Global fracture is determined by the mechanism controlling the development of macroscale bands of localized deformation associated with meso- and microscale relaxation processes. The major result we obtain is that the shift from MHz to kHz EM activity may signal the transition of plastic flow localization from the mesoscale to the macroscale, culminating in global fracture. A complexity measure (Approximate Entropy) and a persistency–anti-persistency measure (Hurst exponent) also give evidence of a two stage-model of EQ preparation process: significant complexity decrease and accession of persistency can be confirmed in the strong kHz EM activity that emerges in the tail of the pre-seismic EM activity. Laboratory experiments on rock samples reveal similar symptoms of an imminent global instability.  相似文献   

Prediction of Chemical Oxygen Demand (COD) Based on Wavelet Decomposition and Neural Networks     

Davut Hanbay  Ibrahim Turkoglu  Yakup Demir 《洁净——土壤、空气、水》2007,35(3):250-254

The chemical oxygen demand (COD) parameter of a wastewater treatment plant is predicted based on wavelet decomposition, entropy, and neural networks (NN) for rapid COD analysis. This paper also describes the usage of wavelet and NNs for parameter prediction. Data from a wastewater treatment plant in Malatya, Turkey, were used. This dataset consists of daily values of influents and effluents for a year. To reduce the dimension of input parameters and to decrease the NN training time, wavelet decomposition and entropy were used. Test results were presented graphically. The test results of the trained model were found to be closer to the measured COD values.  相似文献   

基于TRMM数据的福建省降水时空格局BME插值分析   总被引：1，自引：0，他引：1  

史婷婷  杨晓梅  张涛  刘李  田文君 《地球信息科学学报》2014,(3):470-481

传统空间插值方法可获得福建省区域内降水的总体分布,但该地区气象站点较稀疏且分布不均,导致该区域内降水的空间插值结果误差较大。为提高插值精度,本文利用TRMM卫星数据以弥补站点数据的不足,尝试将TRMM数据作为"软数据"、台站数据作为"硬数据",两者相结合后采用贝叶斯最大熵(Bayesian Maximum Entropy,BME)方法对福建省降水的时空格局进行分析。以2000-2012年近13年20个气象站点的年降水量和月降水量为基础数据,分别利用普通克里格法(Ordinary Kriging,OK)和TRMM为"软数据"的BME插值法,分析福建省多年降水的时空分布格局,并对2种方法的插值结果进行比较。结果表明:在时空分布上,以TRMM数据为辅助变量的贝叶斯最大熵插值结果能更好地体现降水的局部差异特征;在误差评价上,以TRMM数据为辅助变量的贝叶斯最大熵插值结果的MAE和RMSE较小,表明TRMM数据作为"软数据"参与插值的BME方法可以在一定程度上弥补站点数据的不足,有效降低预测结果的绝对误差。通过对福建省降水插值的时空分布格局分析和误差评价可看出,BME插值法通过对基础台站数据,以及TRMM卫星产品数据的利用,使降水的时空分析结果更加真实客观,同时,为TRMM卫星降水数据的应用提供了一个新思路。  相似文献   

黄河流域兰州段生态环境与高质量发展耦合协调关系研究          下载免费PDF全文

李鸿飞  何颖茹  毕晓莉 《干旱区地理》2022,45(4):1244-1253

环境保护作为新常态时代下我国推进生态流域文明体系建设的关键环节,推进黄河流域地区生态环境治理已成为生态文明建设的重要内容。通过选取我国黄河流域唯一被干流贯通的省会城市兰州市为研究对象,根据2010—2019年黄河流域兰州段统计资料,构建了黄河流域兰州段生态环境及高质量发展水平评价指标体系,并利用熵权法构建耦合度模型,全面解析和综合评估了生态环境与高质量发展的耦合水平特征。结果表明：黄河流域兰州段生态环境水平并不高,呈“恶化-好转-恶化-好转”的态势,而高质量发展水平呈“降-升-降-升-降-升”的波动态势。总体来看,兰州市生态环境与高质量发展协调性有待加强,应充分考虑黄河流域整体性特征,坚持生态保护优先原则,同步推进产业的专业化整合与转型升级,提升城市综合治理能力,在城乡融合发展基础上优化城市功能结构布局,最终实现人居生态环境可持续发展。  相似文献   

Microstructure study of soft clayey soil under consolidation by vacuum preloading method     

《Geomechanics and Geoengineering》2013,8(2):97-108

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Cyclic sedimentation of the Karharbari Formation (Damuda Group), Talchir Gondwana basin, Orissa     

Rabindra Nath Hota  Madhusmita Sahoo 《Journal of the Geological Society of India》2009,73(4):469-478

The cyclic arrangement of lithofacies of the Karharbari Formation of the Damuda Group from a part of the Talchir Gondwana basin has been examined by statistical techniques. The lithologies have been condensed into five facies states viz. coarse-, medium-, fine-grained sandstones, shale and coal for the convenience of statistical analyses. Markov chain analysis indicates the arrangement of Karharbari lithofacies in form of fining upward cycles. A complete cycle consists of conglomerate or coarse-grained sandstone at the base sequentially succeeded by medium-and fine-grained sandstones, shale and coal at the top. The entropy analysis categorizes the Karharbari cycles into the C-type cyclicity, which is essentially a random sequence of lithologic states. Regression analysis undertaken in the present study indicates the existence of sympathetic relationship between total thickness of strata (net subsidence) and number and average thickness of sedimentary cycle and antipathic relationship between number and average thickness of sedimentary cycle. These observations suggest that cyclic sedimentation of the Karharbari Formation was controlled by autocyclic process by means of lateral migration of streams activated by intrabasinal differential subsidence, which operated within the depositional basin and the channels carrying coarse grade clastic sediments, which make the cycles thicker, tend to be more common in the areas of maximum subsidence. Clastic sediments issued from the laterally migrating rivers interrupted the cyclic sedimentation of the Karharbari Formation in many instances.  相似文献   

Precipitation,dynamical intermittency,and sporadic randomness     

J.R. Rigby  Amilcare Porporato 《Advances in water resources》2010

While rainfall intermittency is a dynamical phenomenon, little progress has been made in the literature on the link between rainfall intermittency and atmospheric dynamics. We present the basic dynamical models of intermittency that are phenomenologically most similar to rainfall: Pomeau–Manneville Type-III and On–Off. We then illustrate each type with both a 1-D iterative map and a corresponding stochastic process stressing the appearance of these dynamics in high-dimensional (stochastic) systems as opposed to low-dimensional chaotic systems. We show that the pdf of rainfall intensities, the pdf of “laminar phases” (periods of zero rainfall intensity), and the spectrum of the rainfall series all have power-law behavior that is broadly consistent with intermittency in the classic types. Using a seasonal analysis, we find that summer convective rainfall at daily and sub-daily scales seems consistent with features of Type-III intermittency. The correspondence with Type-III intermittency and a preliminary entropic analysis further suggest that rainfall may be an example of sporadic randomness, blending deterministic and stochastic components.  相似文献   

磁异常ΔT三维相关成像   总被引：1，自引：0，他引：1       下载免费PDF全文

郭良辉  孟小红  石磊 《地球物理学报》2010,53(2):435-441

本文将重力和重力梯度数据三维相关成像方法推广到磁力勘探领域,推导并建立了磁异常ΔT的三维相关成像方法,同时提出了基于熵滤波分离异常的三维相关成像算法来提高成像分辨率.组合模型磁异常ΔT数据和实际磁测资料试验分析表明,本文方法能成像出地下地质体的空间赋存状态和等效磁性分布,具有良好的横向和纵向分辨率.  相似文献