Performance and Risks of Salt-Accumulating Renders in Relation to Their Moisture Transport Properties

Salt-accumulating renders are usually applied in several layers with different specific properties of moisture transport. An extensive experimental programme was carried out to establish a relationship between those properties of individual layers and the performance of combined systems on a salt-laden substrate. Each of the 20 renders was characterized separately in absorption and drying tests, vacuum saturation tests, dry cup tests, mercury intrusion porosimetry, and ultrasound wave velocity measurements. Each of the 12 combined render systems was applied on a brick, which was then saturated with a concentrated NaCl solution by free capillary uptake. Subsequently the assembly was closed at the bottom and subjected to an accelerated drying test (50° C and 15% relative humidity). Moisture and salt profiles over the depth were taken regularly during 1 month. The results reveal very different degrees of effectiveness and levels of risk for the substrate, which are related to the moisture transport properties.     

30年来国际“贸易-交通-旅游”(3T)互动的统计分析

经济全球化背景下,国际"贸易-交通-旅游"(3T)互动日益增强。采用1982-2011年时间序列数据,分析国际贸易、交通和旅游总量的发展历程,从进、出口分量视角考察三者相关关系,运用最小二乘法构建回归方程。结果发现:①30年来国际贸易、交通和旅游的发展呈持续增长态势。国际贸易和旅游日益重要。②国际贸易、交通和旅游增长过程具有同步性,表现为波动周期同涨同落。③所构建的回归方程决断系数R²均在0.99以上,国际贸易、交通和旅游存在显著相关性。国际货运与国际贸易,国际客运与国际旅游之间具有确定、直接的因果关系;国际贸易与国际旅游的因果性尚待探究。     

微观视角下中国大城市家庭汽车拥有情况研究——以北京市为例

目前国内从微观角度对家庭汽车所有权的研究很少。本文试图基于对北京市的一项大型问卷调查数据,从微观视角分析中国大城市家庭汽车所有权的主要影响因素。结果显示,中国城市家庭汽车所有权主要受能力因素和需求因素两方面影响。具体而言,家庭收入越高、持有驾照的成员数越多、户主受教育程度越高、户主年龄越大、离地铁站越远,家庭拥有汽车的可能性越大。家庭规模、家庭内的孩子数及是否住在内城等在国外研究中较为重要的解释变量在国内并不显著。有车家庭的户主在日常通勤中对汽车的使用强度较高,说明居民购买汽车主要为满足实际需要,"炫耀性"消费的因素不多。     

长江经济带交通基础设施空间均衡度研究

利用1997-2013年长江经济带各省份数据,研究了交通基础设施空间均衡和极化程度及其影响因素,并构建动态面板数据模型,采用系统GMM估计进行了实证检验。研究结果表明:长江经济带交通基础设施发展较快,但存在空间非均衡和空间极化特征;铁路密度和公路密度的空间非均衡程度依次递减,区域间差距是空间非均衡的主要原因;公路密度空间极化程度不断增加,且高于铁路密度的极化程度;财政支出、国际贸易、人力资源和新经济地理四大因素对交通基础设施空间均衡和极化具有影响,但影响效果不同。本文拓展了交通基础设施的研究,为长江经济带交通基础设施协调发展及互联互通战略顺利实施提供了政策依据。     

Chemical modification of pyroclastic rock by hot water: an experimental investigation of mass transport at the fluid–solid interface

Hydrothermal water–(pyroclastic) rock interactions were examined using flow-through experiments to deduce the effect of mass transport phenomena on the reaction process. A series of experiments were conducted over the temperature range 75–250°C, with a constant temperature for each experiment, and at saturated vapour pressure, to estimate the apparent rate constants as a function of temperature.
Based on the chemistry of analysed solutions, the water–rock interaction in the experiments was controlled by diffusion from the reaction surface and by the existence of a surface layer at the rock–fluid interface, which regulated the chemical reaction rate. The reaction progress depended to a high degree on flow velocity and temperature conditions, with element abundances in the fluid significantly affected by these factors. Mass transport coefficients for diffusion from the rock surface to the bulk solution have been estimated. Ca is selectively depleted under lower temperature conditions ( T  < 150°C), whereas Na is greatly depleted under higher temperature conditions ( T  > 150°C), and K reaction rates are increased when flow velocity increases. Using these conditions, specific alkali and alkali earth cations were selectively leached from mineral surfaces. The 'surface layer' comprised a 0.5–1.8 mm boundary film on the solution side (the thickness of this layer has no dependence on chemical character) and a reaction layer. The reaction layer was composed of a Si, Al-rich cation-leached layer, whose thickness was dependent on temperature, flow velocity and reaction length. The reaction layer varied in thickness from about 10⁻⁴ to 10⁻⁷ mm under high temperature/low fluid velocity and low temperature/high fluid velocity conditions, respectively.     

Scotland's wartime airfields: Conflict and legacy

Prior to the outbreak of World War 2 there were very few active military airfields in Scotland but with the end of Appeasement in 1938 a major programme of expansion was underway. This paper traces the origins of the airfields used in World War 2 and discusses wartime roles and duties undertaken. Spatial distribution and socio‐economic effects are considered along with post‐war uses of this substantial legacy.     

In the footsteps of George Orwell: Patrick McCarthy as Italian correspondent for Tribune, 1978–1980

Abstract

This paper examines Italy's contribution to the United Nations (UN) and how effective this has been in protecting Italian interests. The first part outlines the areas where Italy's input to the UN has been most relevant in terms of ideas, policies and participation, such as for example the campaign to ban the death penalty and its participation in collective security through participation in UN peacekeeping missions. This paper also highlights the critical role that Italy's long-standing positions on UN reform and the enlargement of the Security Council have played in defining Italy's status in the international community, and asks whether there have been significant changes in the traditional Italian position and its loyalty to the UN and, more generally, to the multilateral system. The second part analyzes the origin and rationale of Italy's policies toward the UN and their effectiveness in defining and defending the national interest. It explores the idea that these policies have been determined by the ‘institutional multilateralism’ of the Italian Constitution, the ‘genetic multilateralism’ of the Italian society and the ‘forced multilateralism’ of Italy as a middle-range power. Italy's positions on the UN and its reform are examined in the light of claims that Italy's foreign policy reflects its ‘complex of exclusion’ and presumed lack of influence in the ‘major stakes’ in world diplomacy.     

城市群对外服务功能量化解析——以山东半岛、中原和关中三城市群为例

城市流强度描述了城市对外联系的强弱。是表征城市对外服务功能的量化指标。三个省份的实证检验明显地揭示出城市流与城市中心性具有特别强的相关性。本文以山东半岛、中原和关中城市群为研究区域,通过城市流强度的计算与结构的分析,从城市流视角探讨城市群发展演化机理,揭示出城市群空间结构由简单的单核心结构到复杂的多核心结构的演化过程。文章根据城市流大小和及其产业分布情况,分析了城市群及其中心城市的二、三产业城市流强度与结构,得出城市群整体的对外服务特征,并据此提出改善和提高城市对外服务功能的措施。     

Travel Blending: Whither Regulation?

Travel blending, as a form of travel demand management, has in recent times been celebrated by transport planners as a means of shaping travel behaviour without regulation. Accordingly, travel blending is said to overcome the problems of the state bureaucracy imposing its will upon the individual’s travel choices. In this paper we introduce a Foucauldian analysis to the field of transport in order to examine the assertions made by proponents of travel blending that they are not exercising power in the course of shaping travel behaviour. In particular, we use recent elaborations of Foucault’s work on governmentality to explore the ways in which the sites, subjects and objects of travel are discursively constituted within travel blending thereby enabling new ways of intervening upon the travelling subject. We suggest that a governmentality approach not only provides a fertile means of investigating transport but also reveals travel blending as a regulatory practice serving to structure the individual’s field of action.     

北京市区轨道交通对周边住房租赁价格的影响分析

基于北京市六环内住房租赁样本的交易数据,本文以北京地铁为例,采用空间回归模型实证探讨轨道交通对合租和整租这两种不同方式下的住房租赁价格的影响。结果表明：①基于轨道交通的就业可达性对于租赁价格会产生显著的增值效应,租客愿意为就业可达性较好的住房支付溢价租金。②地铁站点密度对整租的租赁价格具有正向影响,对合租无显著影响,而地铁换乘线路变量未对租赁价格产生显著影响。③轨道交通对合租和整租住房租赁价格的影响随着距离增加呈现差异化的演变规律。合租方式的租赁价格的影响随着实际路网距离的增加呈现单调递减,距站点500m范围内影响最大;而整租方式呈现倒“U”形变化,在500-1500m范围内增值效应最大。针对研究结果,建议政府加大租赁住房供给的同时要充分考虑轨道交通要素,精准施策以实现公共资源的空间高效配置。