Photocatalytic degradation of dyes in wastewater using TiO2/UV in a flat-plate reactor

The photocatalyst TiO₂ with UV irradiation was used to degrade dyes in textile effluent in a flat-plate photoreactor. A test system was built with the reactor area of 1 x 0.3m2, UV light of six 36W-blacklight. TiO₂ powder P25 with BET surface area 50±15m2/g, average primary particle size 21 nm, purity> 99.5% and content of 83.9% anatase and 16.1 % rutile was used as the photocatalyst. A number of dyes commonly present in dyeing wastewater were tested in this study. The different operating parameters, such as dosage of photocatalyst, the structure of the reactor, flow rates through the flat-plate reactor, UV radiation intensity and tilted angle of the reactor, were investigated. The results showed that the photocatalytic process could efficiently remove most of the colour contained in the dyeing wastewater. It was experimentally observed that first-order kinetics was adequate for characterising the process. The flow rate and the tilted angle had some influence on the film thickness of the fluid in the reactor and the empirical correlation between the film thickness of the fluid and these two parameters was developed. The photoreaction rate was mainly determined by the film thickness of the fluid on the reactor surface and the dosage of the photocatalyst. Optimum operating parameters of the system were found to be at the film thickness of about 1.4mm and a TiO₂ dosage of 1 gIL. The higher the UV intensity, the faster the reaction rate was. The results of these experiments showed that this method has the great potential for colour removal from wastewater at commercial scale.

To overcome the common difficulty of separating the used TiO₂ suspension after treatment precipitation followed with filtration was used in this study to determine the separation efficiencies. On the other hand, TiO₂ in a small pillar shape was also studied for photocatalytic degradation of textile dye effluent. The pillar pellet was made in Oegussa Company, Germany ranging from 2.5 to 5.3mm long and with a diameter of 3.7mm. It was almost pure TiO₂ (83.2% anatase and 16.8% rutile), with a S-content of <20 ppm and a CI content of the order of 0.1 wt. %. No further elements are present in contents above 0.05 wt.%. The TiO₂ pillars were placed on the flat-plate reactor that was divided by the rectangular slots and irradiated under UV light when the treated solution went through the reactor. Four dyes and their mixtures were tested. The results showed that the photocatalytic process under this configuration efficiently remove the colour from textile dyeing effluent, and pillar shape TiO₂ photocatalyst was not dissolved in water and very easy to be separated from solution, enabling it to be reused many times. The first-order kinetics was adequate for characterising the photocatalytic degradation process and the photocatalytic performance was comparable to TiO₂ powder. It is believed that the TiO₂ pellet would be a preferable form of photocatalyst in applications for textile effluent treatment process, and other wastewater treatment processes.

A structural events approach to examining long-term change in the Australian trade union movement, 1969-1996

Traditional studies of long-term change in trade union structure have predominantly focused on aggregate trends in union merger activity, in constructing explanations of change. This paper argues that our understanding of structural change in the Australian trade union movement would be better served by a structural events approach that examines the incidence of union formations, dissolutions, and breakaways, in addition to that of union mergers. In doing so, it outlines how these structural events can be identified and measured, and presents the preliminary findings from the methods application.

Regulatory Change v's volume of trade effects in HSIF and HSI volatility

In an earlier paper we adopted a BEKK-GARCH framework and employed a systematic approach to examine structural breaks in the HSIF and HSI volatility. Switching dummy variables were included and tested in the variance equations to check for any structural changes in the autoregressive volatility structure due to the events that have taken place in the Hong Kong market. A Bi-variate GARCH model with 3 switching points was found to be superior as it captured the potential structural changes in return volatilities. Abolishment of the uptick rule, increase of initial margins for the HSIF and electronic trading of HSIF were found to have significant impact on the volatility structure of HSIF and HSI. In this paper we include measures of daily trading volume from both markets in the estimation. Likelihood ratio tests indicate the switching dummy variables become insignificant and the GARCH effects diminish but remain significant.

Project quality management for small and medium enterprises (SMEs) in trade

Managing project quality is becoming focal issue in major enterprises as popular quality programs from International Standard Organization (ISO) such as ISO9000 certification processes gain momentum. Large organizations as well as small-medium enterprises (SMEs) seem to implement this program, albeit for varied reasons. In this paper, we have reported the findings from an action research project conducted in SMEs who are implementing quality management. The findings indicate that external pressures such as regulations, competition and perceived success - defined on their own parameters, may be the drivers and the certification does not necessarily result in better performance. We are in the process of developing a cost-effective guideline/framework - based on this research, for SMEs involved in the certification process. In addition, the results are aimed at informing academia as well as certification bodies of specific concerns with SMEs.

Trade, openness and domestic conflict: an empirical investigation for latin America

This paper explores whether there is an empirical relationship between trade, openness and domestic conflict for Latin America based on the analytical framework of Garfinkel, Skaperdas and Syropoulos (2004). Using ordinal regressions and Markov switching models for seventeen countries, we identify the factors responsible for the initiation and sustenance of domestic conflict. Our overall results suggest that: (i) increased trade openness reduces domestic conflict intensities but (ii) over dependence on agricultural exports, along with poor socio-political performance, lead to sustenance of low intensity conflicts. We also analyze conflict duration using proportional hazard models and find that over-reliance on agricultural exports plays the main role in conflict sustenance after controlling for socio-political factors.

Tourism, trade and domestic welfare

Tourism has been regarded as a major source of economic growth and a source of foreign exchange. It has also been viewed as an activity that imposes costs on the host country. Such costs include increased pollution, congestion and despoliation of fragile environments, and intra-generational inequity aggravation. One aspect that has been ignored is the general equilibrium effects of tourism on other sectors in the economy. This paper presents a model that captures the interdependence between tourism and the rest of the economy, in particular agriculture and manufacturing. An important result obtained is that the tourist boom may 'immiserize' the residents.

Motivations for developing direct trade relationships

Purpose – This study aims to understand buyer and supplier motives for developing direct relationships with their trade partners.

Design/methodology/approach – A total of 18 in-depth interviews were conducted across Victoria and Tasmania (Australia); eight with retail buyers and ten with fresh produce suppliers. Both parties were involved in a direct relationship with their trade partner.

Findings – The research reveals a large variety of motivations that influence buyers and suppliers when deciding whether to operate in a direct or non-direct relationship with their trade partner. Motivations for both parties are remarkably similar, with buyers and suppliers ultimately attempting to minimise the inherent risk associated with operating in a volatile environment.

Research limitations/implications – The study may be limited by the fact that buyers and suppliers of different commodities were included in the study. In addition, the varied nature of the respondents' role may have impacted their judgment. The inability to interview dyads in all cases also limits the research.

Practical implications – This research has implications for both researchers and practitioners already involved in, or considering becoming involved in, a direct trade relationship. Clarification of motivations for bypassing intermediaries shows how both trade partners can minimise external risk and strengthen competitive advantage by assuming a direct relationship.

Originality/value – Extant research within this literary field is largely quantitatively based with researchers focusing on distinct relationship constructs, the definition of relationship marketing and the process of relationship development. In response to these limitations, this research adopted a qualitative approach in examining the core motivations for developing a direct trade relationship within the fresh produce industry.

Genotoxicity assessment of soils from wastewater irrigation areas and bioremediation sites using the Vicia faba root tip micronucleus assay

Genotoxicity potential of soils taken from wastewater irrigation areas and bioremediation sites was assessed using the Vicia faba root tip micronucleus assay. Twenty five soils were tested, of which 8 were uncontaminated soils and taken as the control to examine the influence of soil properties; 6 soils were obtained from paddy rice fields with a history of long-term wastewater irrigation; 6 soils were obtained from bioremediation sites to examine effects of bioremediation; and 5 PAH-contaminated soils were used to examine methodological effects between direct soil exposure and exposure to aqueous soil extracts on micronuclei (MN) frequency () in the V. faba root tips. Results indicate that soil properties had no significant influences on MN frequencies (p > 0.05) when soil pH varied between 3.4 to 7.6 and organic carbon between 0.4% and 18.6%. The MN frequency measured in these control soils ranged from 1.6‰ to 5.8‰. MN frequencies in soils from wastewater irrigation areas showed 2- to 48-fold increase as compared with the control. Soils from bioremediation sites showed a mixed picture: MN frequencies in some soils decreased after bioremediation, possibly due to detoxification; whereas in other cases remediated soils induced higher MN frequencies, suggesting that genotoxic substances might be produced during bioremediation. Exposure to aqueous soil extracts gave a higher MN frequency than direct exposure in 3 soils. However, the opposite was observed in the other two soils, suggesting that both exposure routes should be tested in case of negative results from one route. Data obtained from this study indicate that the MN assay is a sensitive assay suitable for evaluating genotoxicity of soils.

A spill-over theory of international trade unionism

This paper use neo-functionalist and institutionalist theories of geo-political integration to develop a theory of international trade unionism. In brief, the theory asserts that the type of international ‘context’ in which international trade unions operate presupposes the types of ‘imperatives’ that will dominate their interests and concerns. These imperatives are taken to operate along one of three dimensions - industrial, political and ideological, and are seen as evolving in accordance with the ‘logic of spill-over’ in global and sub-global integration processes. Using this interpretation the discussion provides reasons as to why ideological imperatives have historically dominated international trade union thinking, the only exception being regional trade unions operating in Europe, which have evolved beyond the ideological to embrace industrial and political imperatives in their modes of organisation and operation.