Pavement condition description using a deduct point approach.

Paper presented at the 32nd Annual Southern African Transport Conference 8-11 July 2013 "Transport and Sustainable Infrastructure", CSIR International Convention Centre, Pretoria, South Africa.The method to describe pavement condition, as documented in the existing TRH22 document, has specific shortcomings when several defects of slight degree, or when only major defects e.g. potholes exist on a road segment. Following the testing of several alternative techniques, a deduct-point method was implemented and calibrated to calculate different condition and need indices in the Pavement Management System of the Western Cape Provincial Government. This paper describes the background to the deduct-point approach, the processes followed to determine appropriate deduct values for any combination of defect degree and extent, as well as the aggregation of individual deduct values to describe, for example a pavement condition and a reseal need index.This paper was transferred from the original CD ROM created for this conference. The material was published using Adobe Acrobat 10.1.0 Technology. The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: nigel@doctech URL: http://www.doctech.co.zamv201

South African EUCAARI measurements: seasonal variation of trace gases and aerosol optical properties

In this paper we introduce new in situ observations of atmospheric aerosols, especially chemical composition, physical and optical properties, on the eastern brink of the heavily polluted Highveld area in South Africa. During the observation period between 11 February 2009 and 31 January 2011, the mean particle number concentration (size range 10–840 nm) was 6310 cm−3 and the estimated volume of sub-10 μm particles 9.3 μm3 m−3. The aerosol absorption and scattering coefficients at 637 nm were 8.3Mm−1 and 49.5Mm−1, respectively. The mean single-scattering albedo at 637 nm was 0.84 and the A° ngstro¨m exponent of scattering was 1.5 over the wavelength range 450–635 nm. The mean O3, SO2, NOx and H2S-concentrations were 37.1, 11.5, 15.1 and 3.2 ppb, respectively. The observed range of concentrations was large and attributed to the seasonal variation of sources and regional meteorological effects, especially the anticyclonic re-circulation and strong winter-time inversions. In a global context, the levels of gases and particulates were typical for continental sites with strong anthropogenic influence, but clearly lower than the most polluted areas of southeastern Asia. Of all pollutants observed at the site, ozone is the most likely to have adverse environmental effects, as the concentrations were high also during the growing season. The measurements presented here will help to close existing gaps in the ground-based global atmosphere observation system, since very little long-term data of this nature is available for southern Africa.JRC.H.7-Climate Risk Managemen

The causes and consequences of agricultural change : a case study of agricultural commercialization in the communal areas of South Africa

This paper analyses the causes and consequences of agricultural change in two regions of the former Bophuthatswana homeland of South Africa. The paper identifies a number of circumstances which provided the set of comprehensive support services which are essential for the development of commercial agriculture. The changing rural-urban wage differential, and the demise of traditional institutions as well as the drought of the early 1980's were important factors in the changes described. No single factor caused the development of a commercial agriculture, but a package of prime movers was necessary. The broad consequences of the transformation in agriculture has significance for both those with agricultural resources, as well as those without. One of the most important consequences is the creation of a commercial farming class, and conversely, the creation of two other groups: a group of wage labourers and a group of land right owners who lease out their land.For more information on the Agricultural Economics Association of South Africa or subscription to Agrekon, visit http://www.aeasa.org.zahttp://www.aeasa.org.z

South African EUCAARI measurements: Seasonal variation of trace gases and aerosol optical properties

In this paper we introduce new in situ observations of atmospheric aerosols, especially chemical composition, physical and optical properties, on the eastern brink of the heavily polluted Highveld area in South Africa. During the observation period between 11 February 2009 and 31 January 2011, the mean particle number concentration (size range 10–840 nm) was 6310 cm3 and the estimated volume of sub-10 μm particles 9.3 μm3 m−3. The aerosol absorption and scattering coefficients at 637 nm were 8.3 Mm−1 and 49.5 Mm−1, respectively. The mean single-scattering albedo at 637 nm was 0.84 and the Ångström exponent of scattering was 1.5 over the wavelength range 450–635 nm. The mean O3, SO2, NOx and H2S-concentrations were 37.1, 11.5, 15.1 and 3.2 ppb, respectively. The observed range of concentrations was large and attributed to the seasonal variation of sources and regional meteorological effects, especially the anticyclonic re-circulation and strong winter-time inversions. In a global context, the levels of gases and particulates were typical for continental sites with strong anthropogenic influence, but clearly lower than the most polluted areas of south-eastern Asia. Of all pollutants observed at the site, ozone is the most likely to have adverse environmental effects, as the concentrations were high also during the growing season. The measurements presented here will help to close existing gaps in the ground-based global atmosphere observation system, since very little long-term data of this nature is available for southern Africa