Water imbibition of shale and its potential influence on shale gas recovery-a comparative study of marine and continental shale formations

A large volume of fracturing fluid is pumped into a well to stimulate shale formation. The water is imbibed into the reservoir during this procedure. The effect of the imbibed water on gas recovery is still in debate. In this work, we study the spontaneous imbibition of water into marine shale samples from the Sichuan Basin and continental shale samples from Erdos Basin to explore the fluid imbibition characteristics and permeability change during water imbibition. Comparison of imbibition experiments shows that shale has stronger water imbibition and diffusion capacity than relatively higher permeability sandstone. Once the imbibition stops, water in shale has stronger ability to diffuse into deeper matrix, the water content in the main flow path decreases. Experiments in this study show that marine shale has stronger water imbibition capacity than continental shale. The permeability of continental shale decreases significantly with increasing imbibition water volume; however, the permeability of marine shale decreases at first and increases after a certain imbibition time. The induced fracture is obvious in the marine shale. SEM analysis shows that the relationship between the clay mineral and organic matter of continental shale is much more complex than that of marine shale, which may be the key factor restricting the water imbibition because the flow path is trapped by swelled clay minerals. Through this study, we concluded that whether gas recovery benefits from water imbibition depends on three aspects: 1) the diffusion ability of liquid into matrix; 2) the new cracks introduced by imbibed water; and 3) the formation sensibility. This study is useful for optimizing fracture fluids and determining the best flow-back method. (C) 2016 Elsevier B.V. All rights reserved

Optimization of the upper surface of hypersonic vehicle based on CFD analysis

For the hypersonic vehicle, the aerodynamic performance becomes more intensive. Therefore, it is a significant event to optimize the shape of the hypersonic vehicle to achieve the project demands. It is a key technology to promote the performance of the hypersonic vehicle with the method of shape optimization. Based on the existing vehicle, the optimization to the upper surface of the Simplified hypersonic vehicle was done to obtain a shape which suits the project demand. At the cruising condition, the upper surface was parameterized with the B-Spline curve method. The incremental parametric method and the reconstruction technology of the local mesh were applied here. The whole flow field was been calculated and the aerodynamic performance of the craft were obtained by the computational fluid dynamic (CFD) technology. Then the vehicle shape was optimized to achieve the maximum lift-drag ratio at attack angle 3 degrees, 4 degrees and 5 degrees. The results will provide the reference for the practical design

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Understanding the Influence of Side Reactions during Electrochemical CO2 Reduction

The concept and necessity of an "energy transition" has become well-known as the general public acknowledges the severe consequences of climate change. As a side effect of industrial revolution, which has brought advances to modern society by burning fossil fuels, pollutants and greenhouse gases are also released to the atmosphere. As a result, the liveability of earth has dropped substantially, and there exists an urgent need to address decarbonization and energy transition. As a society, we must achieve net-zero by mid of this century to prevent major disasters from happening. One approach which can solve renewable electricity storage together with CO2 elimination issues simultaneously, has attracted considerable attention in recent years – electrochemical CO2 reduction (ECO2R). It functions to reduce the CO2 captured from point sources or air directly, to chemicals or fuels, using the electricity from renewable energy. The chemicals and fuels can be stored and transported more feasibly than electricity. Once being consumed, CO2 will be released to the atmosphere and later again captured. Thus the carbon cycle can be closed.ChemE/Materials for Energy Conversion & Storag

Hoist the Colors: A Sustainable Landmark for Kerkrade Renovation

Architecture and The Built EnvironmentArchitectural Engineerin

Incentivizing household forest management in China's forest reform: Limitations to rights-based approaches in Southwest China

On the basis that property rights provide effective incentives to their users, rights-based approaches have become well-received for purposes of improved resource management, production, and conservation. Recent reform in China's collective-owned forest sector has also been guided by a rights-based approach in generating new incentives and economic benefits for households. Forest property rights have been reconfigured into formal, private, and transferable form, and households are financially compensated for rights' attenuation. In this paper, we draw on a household survey (N = 331) and a series of interviews (N = 29) to empirically examine how three types of forest rights are exercised and perceived by rural households in the Wuling Mountain Area, a relatively poor and mountainous area in Southwest China. Our findings show that although the new rights arrangements are largely perceived as credible by households, the rights are rarely exercised, without tangible contributions to the intended benefits. In explaining this, we find that current economic values of household forests are low. This may suggest that rights-based approaches are unlikely to realize their intended effects if the natural resources themselves are of too little value, an oversight in conventional discussions on resource rights.Organisation and Governanc

In Situ Infrared Spectroscopy Reveals Persistent Alkalinity near Electrode Surfaces during CO₂ Electroreduction

Over the past decade, electrochemical carbon dioxide reduction has become a thriving area of research with the aim of converting electricity to renewable chemicals and fuels. Recent advances through catalyst development have significantly improved selectivity and activity. However, drawing potential dependent structure-activity relationships has been complicated, not only due to the ill-defined and intricate morphological and mesoscopic structure of electrocatalysts, but also by immense concentration gradients existing between the electrode surface and bulk solution. In this work, by using in situ surface enhanced infrared absorption spectroscopy (SEIRAS) and computational modeling, we explicitly show that commonly used strong phosphate buffers cannot sustain the interfacial pH during CO2 electroreduction on copper electrodes at relatively low current densities, <10 mA/cm2. The pH near the electrode surface was observed to be as much as 5 pH units higher compared to bulk solution in 0.2 M phosphate buffer at potentials relevant to the formation of hydrocarbons (-1 V vs RHE), even on smooth polycrystalline copper electrodes. Drastically increasing the buffer capacity did not stand out as a viable solution for the problem as the concurrent production of hydrogen increased dramatically, which resulted in a breakdown of the buffer in a narrow potential range. These unforeseen results imply that most of the studies, if not all, on electrochemical CO2 reduction to hydrocarbons in CO2 saturated aqueous solutions were evaluated under mass transport limitations on copper electrodes. We underscore that the large concentration gradients on electrodes with high local current density (e.g., nanostructured) have important implications on the selectivity, activity, and kinetic analysis, and any attempt to draw structure-activity relationships must rule out mass transport effects.ChemE/Materials for Energy Conversion & Storag

Uncovering coal mining accident coverups: An alternative perspective on China's new safety narrative

China has taken on a series of comprehensive institutional measures to improve the safety of its coal mining industry and workers. Official figures indicate similar reductions to both accidents and fatalities, from which a “new safety narrative” has emerged in official discourses. However, this view neglects the fact that many accidents are concealed or underreported in China's mining sector. This study critically examines China's safety measures with a novel dataset of 180 mining accident coverup cases derived from official, judicial, and media sources. The study's findings support three observations: (i) despite the imposition of stricter regulations and the closure of many informal and small-scale mines, accident coverups have continued at both legal and large-scale mines; (ii) despite increased monitoring including the implementation of a fatality indicator system, accident reporting is consistently manipulated by mine owners, local authorities, and even victims’ families; and (iii) although new stiffer penalties specifically sanction accident coverups, they are rarely imposed. Our results cast doubt on the conceived success of China's new safety narrative and demonstrate how industrial safety measures are deliberately and structurally compromised.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Organisation & Governanc

Understanding spatiotemporal patterns of typhoon storm surge disasters based on their tropical cyclone track clusters in China

Typhoon storm surge disasters have garnered much attention because of their catastrophic damages. We investigated spatiotemporal patterns of typhoon storm surge disasters based on their tropical cyclone track clusters to support disaster mitigation in China. We aggregated 172 typhoon storm surge disasters in the entire cluster. Then, we used the extended Finite-Mixture-Model to categorize these 172 disasters into three clusters according to their track clusters (westward, northward, and westward shift at the coastline). In general, not all temporal distributions of the frequency and damage showed significant trends in the entire cluster and three clusters from 1983–2018. Between 1983‒2000 and 2001‒2018, the average annual frequency increased, and average annual direct economic loss and average annual fatalities decreased in the entire cluster. Although most temporal patterns in the three clusters were similar to those in the entire cluster, a positive growth ratio in the average annual direct economic loss was apparent between 1983‒2000 and 2001‒2018 in Cluster 3. For spatial patterns, southern and eastern regions were more affected by typhoon storm surge disasters than northern regions. In northern regions, Cluster 2 recorded the most disaster occurrences, direct economic losses, and fatalities. Track characteristics and mitigation measures were introduced to help understand disaster spatiotemporal patterns in the entire cluster and three clusters.Electrical Engineering, Mathematics and Computer ScienceSafety and Security Scienc