The ebb and flow of capital in Indonesian coastal production systems

The global fisheries sector has undergone both rapid industrialization and considerable resource depletion. Unlike fisheries in the Northern Hemisphere, the Indonesian (and indeed Southeast Asian) sector is still largely dominated by small-scale producers, who are partially embedded within a subsistence economy. Changes in the nature of production and livelihoods in the fisheries sector appear similar to those in land-based agriculture but have received far less attention in the literature and demand further analysis given the distinct characteristics of the natural resource base. Using national datasets complemented by insights from a two-month period of fieldwork in South Sulawesi, this paper presents the process of capital intensification underpinning national fisheries growth and how it is transforming small-scale production systems. Despite increasing market integration, we found that smallholders have persisted across coastal production systems to an even stronger degree than land-based agriculture. We suggest some reasons why this is so. However, we also observed evidence of internal class differentiation within coastal communities. Such differentiation, combined with resource degradation and depletion, exposes the poorest in the community to enhanced livelihood vulnerability.     

Effects of mellowing sulfate-bearing clay soil stabilized with wastepaper sludge ash for road construction

The main objective of this research was to investigate the effect of mellowing on the swelling properties of stabilized Lower Oxford Clay (LOC), a sulfate-bearing clay soil that has caused concern in the past due to expansion upon stabilization. Two stabilizers were used, quicklime and a more sustainable stabilizer — wastepaper sludge ash (WSA), an industrial by-product used on its own and in combination with either quicklime (CaO) or ground granulated blastfurnace slag (GGBS). Quicklime was used on its own as a control. Compacted cylinders of LOC stabilized with the various stabilizers were made either mellowed (compacted 3 days after mixing with stabilizer) or unmellowed (compacted immediately after mixing with stabilizer). The linear expansion of the stabilized cylinders during moist curing and subsequent soaking was monitored for a total of 100 days. The results obtained showed that the linear expansion of unmellowed stabilized LOC was significantly reduced, and thus in terms of swelling potential, mellowing was not beneficial in the LOC system investigated. The results observed also suggest that there are technological, economic as well as environmental advantages of utilizing WSA and similar industrial by-products, in the stabilization of sulfate-bearing and other clay soils, as an alternative to the traditional stabilizers of lime and/or Portland Cement.     

Short-term droughts forecast using Markov chain model in Victoria,Australia

A comprehensive risk management strategy for dealing with drought should include both short-term and long-term planning. The objective of this paper is to present an early warning method to forecast drought using the Standardised Precipitation Index (SPI) and a non-homogeneous Markov chain model. A model such as this is useful for short-term planning. The developed method has been used to forecast droughts at a number of meteorological monitoring stations that have been regionalised into six (6) homogenous clusters with similar drought characteristics based on SPI. The non-homogeneous Markov chain model was used to estimate drought probabilities and drought predictions up to 3 months ahead. The drought severity classes defined using the SPI were computed at a 12-month time scale. The drought probabilities and the predictions were computed for six clusters that depict similar drought characteristics in Victoria, Australia. Overall, the drought severity class predicted was quite similar for all the clusters, with the non-drought class probabilities ranging from 49 to 57 %. For all clusters, the near normal class had a probability of occurrence varying from 27 to 38 %. For the more moderate and severe classes, the probabilities ranged from 2 to 13 % and 3 to 1 %, respectively. The developed model predicted drought situations 1 month ahead reasonably well. However, 2 and 3 months ahead predictions should be used with caution until the models are developed further.

     

Adsorptive removal of Cu(II) and Pb(II) onto mixed-waste activated carbon: kinetic,thermodynamic, and competitive studies and application to real wastewater samples

This work aimed to investigate the adsorption characteristics, both kinetically and thermodynamically, of Cu(II) and Pb(II) removal from aqueous solutions onto mixed-waste activated carbon, as well as to study the competitive behavior found in mixed heavy metal solution systems. This study shows that activated carbon prepared from mixed waste is an effective adsorbent for the removal of Cu(II) and Pb(II) from aqueous solutions, with the aim of detoxifying industrial effluents before their safe disposal onto water surfaces. The adsorption process was characterized in terms of kinetic and thermodynamic studies. In addition, the influence of presence of Cu(II) and Pb(II) in a competitive system was investigated. The results showed that the maximum adsorption capacities were gained at a pH of 6 with a contact time of 180 min, a metal solution concentration of 300 ppm, and an adsorbent dose of 0.3 g/L. The adsorption process was found to follow a pseudo-first-order kinetic model. Thermodynamic parameters such as ΔG ^o, ΔH ^o, and ΔS ^o showed that the sorption process was spontaneous and endothermic in nature. A competitive study demonstrated the applicability of mixed-waste activated carbon to adsorb Cu(II) and Pb(II) from a solution of mixed metals. In addition, the adsorption capacity was found to be as effective as other adsorbents reported in the literature. The developed adsorptive removal procedure was applied for treatment of real wastewater samples and showed high removal efficiency.