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Porous concrete is a mixture of open‐graded coarse aggregate, water and cement. It is also occasionally referred to as no‐fines concrete or pervious concrete. Due to its…
Porous concrete is a mixture of open‐graded coarse aggregate, water and cement. It is also occasionally referred to as no‐fines concrete or pervious concrete. Due to its high infiltration capacity, it is viewed as an environmentally sustainable paving material for use in urban drainage systems since it can lead to reduced flooding and to the possibilities of stormwater harvesting and reuse. However, the high porosity is due in the main part to the lack of fine aggregate particles used in the manufacture of porous concrete. The purpose of this paper is to present a numerical method to understand more fully the structural properties of porous concrete. This method will provide a useful tool for engineers to design with confidence higher strength porous concrete systems.
In the method, porous concrete is modelled using a discrete element method (DEM). The mechanical behaviour of a porous concrete sample subjected to compressive and tensile forces is estimated using two‐dimensional Particle Flow Code (PFC2D).
Three numerical examples are given to verify the model. A comprehensive set of micro‐parameters particularly suitable for porous concrete is proposed. The accuracy and effectiveness of simulation are confirmed by comparison with experimental results and empirical equations.
The experimental investigations for porous concrete described in this paper have been designed and conducted by the authors. In addition, the type of two dimensional PFC analysis presented has rarely been used to model porous concrete strength characteristics and from the results presented in this paper, this analysis technique has good potential for predicting its mechanical properties.
WHEN THE LIBRARY WORLD asked me for a letter from Finland, I was very glad, for I like writing letters. To me it is a pleasure to write letters. Of course it is equally pleasant to receive letters, and I hope that we can soon receive a letter from Great Britain as a reply for our journal Kirjastolehti.
This article identifies the broad reasons why costs in children's care services might vary, illustrating them with examples from research literature relating to England. An intentionally broad use of ‘costs’ is employed. The literature has been neither systematically nor comprehensively reviewed but does include most of the recent work in the social care field. Articles have been selected to illustrate particular cost associations. This article finds that there is as yet insufficient research into the costs, cost variations or cost‐effectiveness of children's services. However, the findings provide guidance for decision‐makers as they try to understand how resources are currently deployed and why this might be.
This paper brings together findings from current research into mental health and employment from an economic perspective. The economic impact of reduced employment and…
This paper brings together findings from current research into mental health and employment from an economic perspective. The economic impact of reduced employment and productivity for people with mental health problems is described from both individual and societal viewpoints. Interventions reported to have an impact on employment are considered, looking at both clinical interventions that have reported employment outcomes and interventions that have as their primary target the improvement of employment outcomes. The paper also describes the impact of common mental health problems on employment and productivity and reports the findings of some studies in this area. However, the quantity and quality of economic information in this area are limited.
Since the seminal contributions of Chandler and Williamson, asubstantial body of research in industrial organization has examined theperformance benefits of the…
Since the seminal contributions of Chandler and Williamson, a substantial body of research in industrial organization has examined the performance benefits of the organizational innovation of divisionalization. While existing empirical work has, for the most part, utilized a static framework to analyse the performance effects of divisionalization, adopts a dynamic approach, thereby allowing the intertemporal nature of any such performance benefits to be examined. Presents results from the UK manufacturing industry; the model estimated uses a spline function to incorporate differing organizational regimes over time. The results obtained are less supportive of the benefits of divisionalization than certain of the earlier empirical studies; thus the evidence presented lends no support to the view that organizational change provides unambiguous performance benefits for the firm.
The economic phenomenon of “globalization” has broadly affected the health care industry and the medical profession in the late 20th century. Governmental and private…
The economic phenomenon of “globalization” has broadly affected the health care industry and the medical profession in the late 20th century. Governmental and private sector managed care reach is expanding globally, as patients are “ecuritized” and traded as covered lives. Arbitrage of health care goods and services is creating commoditization effects, including trans‐border parallel markets (i.e. black markets). Consumers and governments are becoming concerned about privacy issues and product standardization, while Third World challenges remain in the public health realm (i.e., infectious pandemics, sanitation, nutrition and overpopulation).
It has often been said that a great part of the strength of Aslib lies in the fact that it brings together those whose experience has been gained in many widely differing fields but who have a common interest in the means by which information may be collected and disseminated to the greatest advantage. Lists of its members have, therefore, a more than ordinary value since they present, in miniature, a cross‐section of institutions and individuals who share this special interest.
Among the top management issues covered in this section are: leadership to promote change; issues of corporate culture; effective international strategy; environmental leadership; investment in Eastern Europe; and developing “world‐class” manufacturing strategy.
Of the thermoplastics group of materials, unplasticised polyvinyl chloride, commonly known as rigid PVC, appears to have made the slowest progress in the U.K. It was…
Of the thermoplastics group of materials, unplasticised polyvinyl chloride, commonly known as rigid PVC, appears to have made the slowest progress in the U.K. It was introduced here shortly after the war, but, as recently as 1958, the annual usage for industrial pipes was estimated at only 500 tons. In the same year, France, Holland and Italy processed approximately 4,000, 8,000 and 12,000 tons respectively. This article indicates the scope of the material in corrosive environments.