Molecular transport of methane, ethane and nitrogen and the influence of diffusion on the chemical and isotopic composition of natural gas accumulations

Laboratory experiments have been performed to determine diffusion coefficients of natural gas components (methane, ethane and nitrogen) and isotope fractionation effects under simulated in situ pressure (up to 45 MPa effective stress) and temperature conditions (50–200°C) in water‐saturated pelitic and coarse‐grained rocks. Effective diffusion coefficients of molecular nitrogen (0.39 × 10^?11 to 21.6 × 10^?11 m² sec^?1 at 90°C) are higher than those for methane (0.18 × 10^?11 to 18.2 × 10^?11 m² sec^?1 at 90°C). Diffusive flux rates expressed in mass units are generally higher for N₂ than for CH₄. Both methane and (to a lesser extent) nitrogen diffusion coefficients decrease with increasing total organic carbon (TOC) content of the rock samples because of sorption processes on the organic matter. This effect decreases with increasing temperature. Effective diffusion coefficients increase upon a temperature increase from 50 to 200°C by a factor of four. Effective diffusion coefficients and steady‐state diffusive flux decrease with effective stress. Stationary diffusive fluxes drop by 50–70% for methane and 45–62% for nitrogen while effective diffusion coefficients are reduced by 38% (CH₄) and 32–48% (N₂), respectively. Isotope fractionation coefficients of diffusive transport are higher for methane (?1.56 and ?2.77‰) than for ethane (?0.84 and ?1.62‰). Application of the experimental results to geological systems show that diffusive transport has only a low transport efficiency. Significant depletion of natural gas reservoirs by molecular diffusion is only expected in cases of very poor caprock qualities (in terms of thickness and/or porosity) and over extended periods of geological time. Under these circumstances, the chemical and isotopic composition of a gas reservoir will change and maturity estimates based on these parameters may be deceptive. To account for these potential effects, nomograms have been developed to estimate diffusive losses and apply maturity corrections.     

Capacity Building toward Resilience: How Communities Recover,Learn, and Change in the Aftermath of Extreme Events

When faced with natural disasters, communities respond in diverse ways, with processes that reflect the extent of damage experienced by the community, their resource availability, and stakeholder needs. Local‐level processes drive decisions about mitigating future flood risks, such as if, how, and where to rebuild, as well as changes in zoning practices and public outreach programs. Because of their potentially recurring nature, floods offer an opportunity for communities to learn from and adapt to these experiences with the goal of increasing resiliency through deliberation, modification of former policies, and adoption of new policies. By following the response to the September 2013 floods in seven Colorado communities, this study investigates if, how, and why communities successfully learn from extreme events and change their local government policies to increase resilience and decrease vulnerability to future floods. We find that greater openness of post‐flood decision process is associated with more in‐depth deliberation, learning, and more substantive and frequent policy change.     

Unlock the Volume: Towards a Politics of Capacity

In recent years “volume” has become a key analytic idea, and tool, for re‐imagining and making sense of historical and contemporary socio‐cultural and geopolitical phenomena. This paper argues that this important work could be pushed in new directions by thinking seriously of how volume might otherwise be interpreted spatially, as capacity. Accordingly, in this paper, we address what we call a “politics of capacity”. To do so, we draw specifically on debates in carceral geography and, in particular, the pressures on the prison system to illustrate our argument. Drawing on notions of “operational capacities” and “capacity building” in the prison setting, we outline a manifesto for volumetric thinking that moves beyond expressions of power that cut through height, depth and angles, to an understanding of how power is conveyed through maximum and minimum capacities; density and mass; and capacity‐building techniques.     

Effect of the joint type on the bearing capacity of a multi–drum column under static load

The results of an experimental study on the effect of the joints between the blocks on the ultimate bearing capacity of a multi-drum column loaded to centric vertical force and horizontal force in the middle of its height are shown. The column is approximately 2.5 m high, with one hinge at the top and another hinge at the bottom. Four types of joints between the blocks were considered: a dry joint (column C-DJ) and joints with stone powder (column C-SPJ), lead (column C-PBJ), and epoxy (column C-EPJ). The applied vertical and horizontal forces, horizontal displacement, vertical strains, and horizontal circumferential strains in the middle of the column height, as well as shortening of the column, were measured. Under axial compression, ratios between the ultimate load bearing capacities of tested columns were C-EPJ: C-DJ: C-SPJ: C-PBJ = 1: 0.68: 0.59: 0.51. The bearing capacity of the tested columns with regard to the horizontal force depended on the level of the applied centric compression force. Columns with soft joints (C-PBJ, C-SPJ) had the largest shortening and the largest horizontal displacements for the equal forces.     

Modernist Unreinforced Masonry (URM) Buildings of Barcelona: Seismic Vulnerability and Risk Assessment

The main objective of this work is to assess the vulnerability and seismic risk of typical existing modernist unreinforced masonry (URM) modernist buildings and aggregates situated in the Eixample district of Barcelona, part of the architectural heritage of the city. The context of the analysis is the methodology proposed by the Risk-UE project. The buildings are characterized by their capacity spectrum and the earthquake demand is defined by the 5% damped elastic response spectrum, considering deterministic and probabilistic earthquake scenarios. A discussion addresses the basis of the seismic damage states probabilities and the calculated damage index. An important research effort has been focused on the buildings modeling. All the architectural elements and their mechanical properties have been studied and evaluated accurately. It has been evidenced that a detailed and complete knowledge of all the structural elements existing in this type of buildings influence directly their behavior and hence the calculations and the results. The analysis of the isolated buildings and of the aggregate building has been performed for both mentioned seismic scenarios. Finally, a complete discussion of the results is included.     

动态能力的特征及构成维度研究

本文分析了构成企业动态能力的五个能力特征,提出了企业动态能力的四个构成维度,即组织文化、组织过程、资产和技术状况、成长路径,为动态能力理论的研究和应用提供了一个新的思路。     

Moderating Local Capacity: Exploring EO 12372's Intergovernmental Review Effects on Federal Grant Awards

This article asks whether the Reagan Executive Order (EO) 12372 matters for intergovernmental fiscal relations today. To address this question, federal grant receipts from programs that are, and programs that are not, covered by EO 12372 are compared by examining the differential effects of political and local administrative capacity on each. Grant receipts are examined by coding federal grant award data from 1993 to 2003 using Catalog of Federal Domestic Assistance reference numbers. In the case state, Kentucky, Area Development Districts are the regional functionaries for the state single point of contact clearinghouse, by virtue of which status they review proposals for federal funding originating in, or affecting, their districts. Since federal award decisions take clearinghouse information into account on grant programs covered by EO 12372, differences in the effects of local capacity on receipt of grants covered and not covered by the EO are expected. Methodology used in this post‐only analysis is pooled cross‐sectional time series analysis with panel corrected standard errors. Results focus attention on the differential effects of government administrative and political capacity as they apply to federal grants covered, and not covered, by the EO.     

旅游环境容量调控系统的探讨

无序、失控的假日旅游客流对旅游业永续发展构成了深度危害。本初步探讨了旅游环境容量调控系统的构成、功能及其调控途径与手段。     

Israeli feminist geography: women,gender and queer geographies

Abstract

This article charts the changing knowledges within Israeli feminist geography in the last few decades. It briefly reviews some of the topics that characterize Israeli scholarship, and in particular the ways in which the academic knowledge changed from the focus on women’s geography, to feminist and gendered analysis of spaces, to a more recent focus on sexuality and gender. We argue that it is not that one knowledge replacing others, but rather all knowledges and approaches exist simultaneously within Israeli geography today.     

Imizamo Yethu: a Case Study of Community Resilience to Fire Hazard in an Informal Settlement Cape Town,South Africa

Imizamo Yethu, in Cape Town, is one of the many informal settlements in South Africa's post-Apartheid urban landscape. Residents live in abject poverty and are potentially vulnerable to a range of environmental hazards, of which fire hazard is one of the most common. A major fire, on the 8 February 2004, caused significant damage to housing and infrastructure, resulting in widespread homelessness and loss of personal possessions. Despite this, there was minimal loss of life and few major injuries. The community re-grouped after the fire and Imizamo Yethu has remained viable as a community to the present day. Contemporary geographical research on hazards emphasises aspects of community vulnerability and resilience. The present paper identifies and examines factors that enhance community resilience in the informal settlement of Imizamo Yethu, particularly in response and recovery to fire events. A survey completed in the aftermath of the 2004 fire found that social networks, some formal community institutions that foster community participation and the resourcefulness of individuals were the most important factors underpinning resilience.