Microstructural analysis of surface and interface zones in concrete

Several of OPC paste and concrete specimens, with different mix proportions, were cast against CPF and impermeable formwork (IF) and the profiles of pore structure, microhardness and scratch hardness of the cover zone were established. The chloride ingress and the depth of carbonation of the surface zone of concrete cast against CPF and IF were investigated. The main mechanisms controlling the ECR processes and the factors affecting such treatment were critically reviewed. Subsequently, as a means of restoring passivation of steel embedded in carbonated concrete, such HCP specimens were subjected to ECR. The influence of ECR on the chemistry of the pore solution and the microstructure of the surface and the steel/cement past interface zones were also studied. The main findings of this investigation were as follows: (a) The thickness of the microstructure gradient of cover concrete is significantly decreased with increasing period of water curing but is relatively unaffected by curing temperature, w/e ratio and the use of cement replacement materials. (b) The scratch hardness technique was shown to be potentially useful for characterising the microstructure and microhardness gradients of the surface zone. (c) A relationship between the microstructure gradient and mass transport properties of the surface zone was established. (d) The use of CPF resulted in a significant reduction in porosity of both the cement paste matrix and the aggregate/cement paste transition zone, and a marked improvement in the resistance of the surface zone to carbonation and the ingress of chloride ions. (e) The ECR treatment resulted in a marked densification of the pore structure and in changes to the pore solution chemistry and the cement phases of near-surface and steel/cement paste transition zones. This effect was more pronounced with current density, period of treatment and particularly with the use of sodium phosphate as an electrolyte.

Stand-alone groundwater desalination system using reverse osmosis combined with a cooled greenhouse for use in arid and semi-arid zones of India

In many areas of northern India, salinity renders groundwater unsuitable for drinking and even for irrigation. Though membrane treatment can be used to remove the salt, there are some drawbacks to this approach e.g. (1) depletion of the groundwater due to over-abstraction, (2) saline contamination of surface water and soil caused by concentrate disposal and (3) high electricity usage. To address these issues, a system is proposed in which a photovoltaic-powered reverse osmosis (RO) system is used to irrigate a greenhouse (GH) in a stand-alone arrangement. The concentrate from the RO is supplied to an evaporative cooling system, thus reducing the volume of the concentrate so that finally it can be evaporated in a pond to solid for safe disposal. Based on typical meteorological data for Delhi, calculations based on mass and energy balance are presented to assess the sizing and cost of the system. It is shown that solar radiation, freshwater output and evapotranspiration demand are readily matched due to the approximately linear relation among these variables. The demand for concentrate varies independently, however, thus favouring the use of a variable recovery arrangement. Though enough water may be harvested from the GH roof to provide year-round irrigation, this would require considerable storage. Some practical options for storage tanks are discussed. An alternative use of rainwater is in misting to reduce peak temperatures in the summer. An example optimised design provides internal temperatures below 30EC (monthly average daily maxima) for 8 months of the year and costs about €36,000 for the whole system with GH floor area of 1000 m2 . Further work is needed to assess technical risks relating to scale-deposition in the membrane and evaporative pads, and to develop a business model that will allow such a project to succeed in the Indian rural context.

International business research and risky investments, an analysis of FDI in conflict zones

The purpose of this paper is to examine the determinants of a firm's strategy to invest in a conflict location. To the best of our knowledge, this has not been done before. We examine this using a standard model of international business, overlaid with the fundamental approach to corporate social responsibility. We start with the population of multinationals who have chosen to invest in low income countries with weak institutions. We then split this sample in order to distinguish between firms that have invested in conflict regions compared to those that have not. Our analysis then proceeds to explain the decision of those firms to invest in conflict locations using a simple Probit model. We find that countries with weaker institutions and less concern about corporate social responsibility (CSR) are more likely to invest in conflict regions. Finally, firms with more concentrated ownership are more likely to invest in such locations. © 2012 Elsevier Ltd.

Investing in conflict zones:a firm-level analysis

The purpose of this paper is to examine, using panel data econometric techniques, the determinants of a firm’s strategy to invest in a conflict location. To the best of our knowledge this has not been done before. We use a large database of firm-level data that includes 2858 multinational firms that have a subsidiary in a developing country (during 1999-2006). Out of these firms 290 are classified as having a subsidiary in a conflict location. The choice of a conflict location is based on data from the Inter Country Risk Guide (ICRG). We start with the population of multinationals who have chosen to invest in low income countries with weak institutions. Our analysis then proceeds to explain the decision of those firms to invest in conflict locations. We have four hypotheses: (1) Firms with concentrated ownership are more likely to invest in a conflict region; (2) Firms from countries with weaker institutions are more likely to invest in conflict regions; (3) Firms and Countries with less concern over corporate social responsibility are more likely to invest in conflict countries; and (4) that there is large sector level differences in the propensity to invest in a conflict region. The results suggest that all of these hypotheses can be confirmed.