Removal of textile basic dye from aqueous solutions using sawdust as bio‐adsorbent

The ability of low cost bio‐adsorbent sawdust to remove basic dye (methylene blue) from aqueous solution is investigated using it in two different forms: in raw form and in chemically treated (with sulphuric acid) form. The effect of contact time, dye concentration, adsorbent dose and the kinetics of adsorption were studied in batch experiments. At neutral pH and 4?gm/l of chemically activated and raw sawdust adsorbents, removal of 98.12% and 97.18% of methylene blue dye (at 100?mg/l concentration) from the aqueous solution, was the best result obtained during study. An average percentage removal difference of less than 5%, between two adsorbents was achieved under different conditions in the experiments. The data fit well in Freundlich isotherm.     

Photodegradation of selected β-blockers in aqueous fulvic acid solutions: kinetics, mechanism, and product analysis

The photodegradation of the widely used β-blockers atenolol and metoprolol were investigated in the presence of fulvic acid (FA) under simulated sunlight. Both atenolol and metoprolol undergo indirect photodegradation in the FA solutions. The triplet excited state of FA (³FA^∗) was verified to be main reactive species responsible for the photosensitized degradation of β-blockers. An electron transfer mechanism for the interaction between β-blockers and ³FA^∗ was proposed on the basis of a series of experiments. Magnetic property of metal ions exhibited significant impact on photosensitized degradation. Diamagnetic metal ions such as Mg²⁺, Ca²⁺, Zn²⁺, and Al³⁺ negligibly affected the degradation. In contrast, paramagnetic metal ions including Mn²⁺, Cu²⁺, Fe³⁺, and Cr³⁺ markedly inhibited the reactions in the order of Cr³⁺ < Fe³⁺ < Cu²⁺ < Mn²⁺. The inhibition was related to the complexation ability with FA. By LC-ESI-MS/MS analysis, deisopropyl-atenolol (metoprolol) was identified as the main photosensitized product. The degradation pathways of β-blockers involving electron transfer processes were proposed. This finding strongly suggests that ³FA^∗ was important reactive species for the degradation of β-blockers in natural waters.     

Safety climate in conditions of construction subcontracting: a multi‐level analysis

A multi‐level safety climate model was tested in the Australian construction industry. Subcontracted workers’ perceptions of the organizational safety response (OSR) and supervisor safety response (SSR) in their own organization and that of the principal contractor were measured using a safety climate survey administered at a large hospital construction project in Melbourne. One hundred and fourteen construction workers completed the survey, representing nine subcontractors engaged at the project. Two requisite conditions for the existence of group‐level safety climates, i.e. (1) within‐group homogeneity; and (2) between‐group variation were satisfied for perceptions of subcontractors’ OSR and SSR. This supports the contention that subcontractors working in a single construction project exhibit a unique group‐level safety climate. Subcontracted workers also discriminated between group‐level safety climates (i.e. the SSR) in their own and in the principal contractor’s organizations. The results suggest some cross‐level influence. Perceptions of the SSR were positively predicted by perceptions of the OSR in both the principal and subcontractor organizations. Perceptions of the OSR of the principal contractor were also a significant predictor of the perceived OSR and SSR in the subcontractor organizations. Perceptions of the subcontractors’ SSR were a significant predictor of the rate of lost‐time and medical treatment incidents reported by the subcontractor. Although perceptions of the principal contractor’s SSR were not directly related to subcontractors’ injury rates, they were a significant predictor of subcontractors’ SSR, revealing an indirect link. The results suggest that supervisory personnel (e.g. foremen and leading hands) play an important role in shaping safety performance in subcontracted workgroups.     

Input structure of the construction industry: a cross‐country analysis, 1968–90

During the past several decades, globalization has led to the integration of product markets. Rapid increases in cross‐border economic, social, technological and cultural exchange have become the key elements of knowledge diffusion and thus technology spillovers among countries. As a result, the debate as to whether absolute convergence occurs at the cross‐country level has increasingly attracted the attention of researchers. The aim of this study is to examine the changes in the input structure of the construction industry in nine developed countries between the late 1960s and 1990 and to evaluate whether convergence occurs at input industry level. The analysis of the technical coefficients for 35 industries reveals that, across countries and over time, not only the key inputs but also the new high and low input industries are similar. The estimation of variance factors on the other hand suggests that (1) during the sample period, the input structure of the industry is dominated by divergence rather than convergence; (2) among the input industries, services in particular tend for convergence; and (3) manufacturing inputs provide a mixed picture where only a few inputs show convergence and the remaining inputs show in general weak divergence.     

An analysis of sustainable development and environmental protection in postcommunist countries: the case of croatia‐a view point

The paper analyses the origins, the definitions, and the implementation of sustainable development in the post‐communist countries of Central and Eastern Europe, using Croatia as an example. The overview of events in environmental concern world‐wide, in the last 25 years, shows that there is evidence of fast changes which have left the former communist countries behind. The major concern of the paper is the lack of an agreed upon definition and criteria on what sustainable development actually represents, and why it is still an odd subject in the Central and Eastern European region. Five recognition criteria described in the open literature are compared with the situation in the region. Using the examples of implementation of new UN Conventions, accepted at the UNCED Conference in Rio de Janeiro in 1992, the paper discusses the shortcomings and obstacles to current policies of sustainability.     

Studies on Mg/Fe hydrotalcite‐like – compound (HTlc): removal of Chromium (VI) from aqueous solution

The affinity of Mg/Fe hydrotalcite‐like‐compound (HTlc) for the removal of Cr (VI) from aqueous medium was studied as a function of pH, contact time, temperature, HTlc dose and Cr (VI) concentration. The fraction of Cr (VI) removal decreases with increase in pH of 3 to 10. The reaction kinetic study was undertaken by considering adsorption of Cr (VI) on the outer surface as well as diffusion within the pores of the adsorbent. The adsorption follows first order kinetics. The adsorption data fit well with the Langmuir isotherm model in the temperature range 30–50°C and the thermodynamic parameters viz. ΔG°, ΔH° and ΔS° were calculated to predict the nature of adsorption. The positive value of ΔH° indicates that the adsorption process is endothermic in nature.     

Stakeholder impact analysis of infrastructure project management in developing countries: a study of perception of project managers in state‐owned engineering firms in Vietnam

Construction projects can involve a diverse range of stakeholders and the success of the project depends very much on fulfilling their needs and expectations. It is important, therefore, to identify and recognize project stakeholders and develop a rigorous stakeholder management process. However, limited research has investigated the impact of stakeholders on construction projects in developing countries. A stakeholder impact analysis (SIA), based on an approach developed by Olander (2007), was adopted to investigate the stakeholders’ impact on state‐owned civil engineering projects in Vietnam. This involved the analysis of a questionnaire survey of 57 project managers to determine the relative importance of different stakeholders. The results show the client to have the highest level of impact on the projects, followed by project managers and the senior management of state‐owned engineering firms. The SIA also provides suggestions to project managers in developing and evaluating the stakeholder management process.     

Learning from Southern California: a typology of neighborhood‐scale projects,the emerging metropolitan form and the implications for public policy

This paper presents a typology of neighborhood‐scale projects in Southern California, examines their impact on the emerging metropolitan form and discusses policy implications. This region is growing fast and is facing several problems. It is also the focus of inquiry of municipal control of land use regulations that support Tiebout sorting and contribute to social and spatial segregation. Given this, the paper examines whether certain types of projects are being built in certain types of cities and whether these projects are likely to support Tiebout sorting. A survey of city planners was used to collect data about the attributes of 169 projects. The results suggest that the association between the attributes of projects and characteristics of cities is not strong and reveal how certain types of projects might address some of the region’s problems. The paper concludes with a discussion of opportunities to create a better metropolitan form.