杜波依斯对解决美国黑人问题道路的探索

杜波依斯一生都在为争取黑人的平等权利而斗争。但是,在不同时期,他对美国黑人问题的认识不同,解决方案因而不断调整。     

Solutions and frictions in civic hacking: collaboratively designing and building wait time predictions for an immigration office

Smart and data-driven technologies seek to create urban environments and systems that can operate efficiently and effortlessly. Yet, the design and implementation of such technical solutions are full of frictions, producing unanticipated consequences and generating turbulence that foreclose the creation of friction-free city solutions. In this paper, we examine the development of solutions for wait time predictions in the context of civic hacking to argue that a focus on frictions is important for establishing a critical understanding of innovation for urban everyday life. The empirical study adopted an ethnographically informed mobile methods approach to follow how frictions emerge and linger in the design and production of queue predictions developed through the civic hacking initiative, Code for Ireland. In so doing, the paper charts how solutions have to be worked up and strategies re-negotiated when a shared motivation meets different data sources, technical expertise, frames of understanding, urban imaginaries and organisational practices; and how solutions are contingently stabilised in technological, motivational, spatiotemporal and organisational specificities rather than unfolding in a smooth, linear, progressive trajectory.     

Devolatilization‐induced pressure build‐up: Implications for reaction front movement and breccia pipe formation

Generation of fluids during metamorphism can significantly influence the fluid overpressure, and thus the fluid flow in metamorphic terrains. There is currently a large focus on developing numerical reactive transport models, and with it follows the need for analytical solutions to ensure correct numerical implementation. In this study, we derive both analytical and numerical solutions to reaction‐induced fluid overpressure, coupled to temperature and fluid flow out of the reacting front. All equations are derived from basic principles of conservation of mass, energy and momentum. We focus on contact metamorphism, where devolatilization reactions are particularly important owing to high thermal fluxes allowing large volumes of fluids to be rapidly generated. The analytical solutions reveal three key factors involved in the pressure build‐up: (i) The efficiency of the devolatilizing reaction front (pressure build‐up) relative to fluid flow (pressure relaxation), (ii) the reaction temperature relative to the available heat in the system and (iii) the feedback of overpressure on the reaction temperature as a function of the Clapeyron slope. Finally, we apply the model to two geological case scenarios. In the first case, we investigate the influence of fluid overpressure on the movement of the reaction front and show that it can slow down significantly and may even be terminated owing to increased effective reaction temperature. In the second case, the model is applied to constrain the conditions for fracturing and inferred breccia pipe formation in organic‐rich shales owing to methane generation in the contact aureole.     

Flood risk mapping in southwestern Nova Scotia: Perceptions and concerns

Flood risk mapping allows for informed decision making regarding personal and community planning. Resistance to flood risk mapping can be driven by potential decline of property values. This paper explores resistance to flood risk mapping through the lens of climax thinking. Climax thinking is a novel theory guiding explorations of resistance to proposed land use changes. The aim of this study was to understand flood experiences, the presence of resistance to flood risk mapping, and whether climax thinking could help explain this resistance. To address this, surveys were administered to residents in the Nova Scotian towns of Liverpool and Bridgewater. We found that one third of respondents have experienced flooding, yet the majority have not seen a flood risk map, nor were they concerned about the potential impacts of flooding. Only one sixth of respondents exhibited resistance to flood risk mapping because of potential loss to property value. Dimensions of climax thinking were predictive of this resistance, specifically ignorance of an individual's own ability to adapt and inability to recognize the impact of their adaptation decisions on others, which together quadrupled the predictive power of the ordinal regression model. These insights can be applied to support the acceptance of flood risk mapping.     

The Future of Collective Farms' Built Social Infrastructure: Choosing Between Central Place and Network Theories

The aim of this paper is to discuss local and regional planning and development practices in a post‐socialist country such as Estonia. Two approaches — central places and network theories — are used as a conceptual basis. According to the first hypothesis, planning and development of social infrastructure (e.g. schools, sports halls) has remained based on the central place theory — as an outdated planning approach — in Estonia. The second hypothesis argues that while, on the one hand, the application of the network paradigm and increased cooperation between local communities would considerably save public resources, on the other hand, because of the path dependency of Soviet centralized planning and development practices, the networking and lobbying takes place vertically rather than horizontally. This restricts both administrative cooperation and networking on the local and regional levels. The paper consists of three parts. The first part describes the turn in Western planning theory: the shift from normative top‐down planning to a bottom‐up approach and networking. The second part analyses critically the Soviet and post‐Soviet planning theory and practices: the planning and development culture created during the Soviet era. Finally we present a case study of a community planning procedure in the Suure‐Jaani locality — a good example of the influence of historical changes in the settlement system and planning culture of the past on current development.     

邻避设施国内外研究进展

随着城市化进程的加快,城市规模不断扩大,公共设施水平逐步提高,不可避免地需要布局邻避设施,即NIMBY,Not In My Back Yard,"不要布局在我家后院"的设施。随着人们自我健康和保护意识的增强,邻避设施由于负面外部性的存在而面临着"邻避"的风险。如何减少其负面外部性,实现成本-效益对等,解决邻避冲突是邻避设施布局的关键。本文在总结邻避设施的概念的基础上,从邻避设施的分类入手,分别分析了国内外邻避设施的研究进展,综述了国内外邻避设施的类型、规模、选址、与周围环境的协调、困境、邻避冲突及解决方案等进展与不足,提出了未来研究的新视角,以期从发达国家邻避设施的布局中汲取经验,给我国有益的启示。     

Solubility of quartz in crustal fluids: experiments and general equations for salt solutions and H2O–CO2 mixtures at 400–800°C and 0.1–0.9 GPa

The solubility of quartz has been measured in a wide range of salt solutions at 800°C and 0.5 GPa, and in NaCl, CaCl₂ and CsCl solutions and H₂O–CO₂ fluids at six additional P–T conditions ranging from 400°C at 0.1 GPa to 800°C at 0.9 GPa. The experiments cover a wide range of compositions along each binary. At P–T conditions where the density of pure water is low (0.43 g cm^?3), addition of most salts produces an enhancement of quartz solubility at low to moderate salt concentrations (salt‐in effect), although quartz solubility falls with further decrease in X_H2O. At higher fluid densities (0.7 g cm^?3 and greater), the salt‐in effect is generally absent, although this depends on both the cation present and the actual P–T conditions. The salt‐in effect is most readily produced by chloride salts of large monovalent cations, while CaCl₂ only produced a salt‐in effect at the most extreme conditions of high‐T and low‐P investigated (800°C at 0.2 GPa). Under most crustal conditions, the addition of common salts to aqueous fluids results in a lowering of quartz solubility relative to that in pure water (salt‐out effect). Comparing quartz solubility in different fluids by calculating X_H2O on the basis that all salts are fully associated under all conditions yields higher quartz solubility in solutions of monovalent salts than in solutions of divalent salts, absolute values are also influenced by cation radius. Quartz solubility measurements have been fitted to a Setchenow‐type equation, modified to take account of the separate effects of both the lowering of X_H2O and the specific effects of different salts, which are treated as arising through distinct patterns of non‐ideal behaviour, rather than the explicit formation of additional silica complexes with salt components. Quartz solubility in H₂O–CO₂ fluids can be treated as ideal, if the solvation number of aqueous silica is taken as 3.5. For this system the solubility (molality) of quartz in the binary fluid, S is related to its solubility in pure water at the same P–T conditions, S^o, by: Quartz solubility in binary salt systems (H₂O–RCl_n) can be fitted to the relationship: where salt concentration mRCl_n is expressed as molality and the exponent b has a value of 1 except under conditions where salting‐in is observed at low salt concentrations, in which case it is <1. Under most crustal conditions, the solubility of quartz in NaCl solutions is given to a good approximation by: We propose that quartz solubility in multicomponent fluids can be estimated from an extended expression, calculating X_H2O based on the total fluid composition (including dissolved gasses), and adding terms for each major salt present. Our experimental results on H₂O–NaCl–CO₂ fluids are satisfactorily predicted on this basis. An important implication of the results presented here is that there are circumstances where the migration of a fluid from one quartz‐bearing host into another, if it is accompanied by re‐equilibration through cation exchange, may lead to dissolution or precipitation of quartz even at constant P and T, with concomitant modification of the permeability structure of the deep crust.