Air Pollution Control Association Critical Reviews Program

This is the fourth in the series of Critical Reviews commissioned by the APCA Board of Directors. The first Critical Review "Regulations for the Control of Particulate and Sulfur Oxides Emissions" was published in 1974 and the topic is still timely. The second Critical Review "Regulations for the Control of Hydrocarbon Emissions (from Stationary Sources) and Odorous Pollutants" was published in 1975. In light of recent developments concerning hydrocarbon emissions from stationary sources, this Critical Review is again very timely. The third Critical Review "The Effect of Air Pollution Control Regulations on Land Use Planning" will soon be published in final form. Now we have the fourth in the series, "A Critical Review of Air Pollution Index Systems in the United States and Canada" and "Status Report on Federal Regulations for New Source Performance Standards".     

Printed wiring boards for mobile phones: characterization and recycling of copper

The popularization of mobile phones, combined with a technological evolution, means a large number of scrap and obsolete equipment are discarded every year, thereby causing economic losses and environmental pollution. In the present study, the printed wiring boards scrap of mobile phones were characterized in order to recycle some of the device components, using techniques of mechanical processing, hydrometallurgy and electrometallurgy. The use of the techniques of mechanical processing (milling, particle size classification, magnetic and electrostatic separation) was an efficient alternative to obtain a concentrated fraction (mainly iron in the magnetic fraction and copper in the conductive fraction) and another fraction containing polymers and ceramics. At the end of mechanical processing, a concentrated fraction of metals could be obtained with an average concentration of 60% copper. This concentrated fraction in metals was dissolved in aqua regia and sent to electrowinning to recover 92% of the dissolved copper. The obtained cathodes have a copper content above 95%, which demonstrates the technical feasibility of recovery of copper using the techniques of mechanical processing, hydrometallurgy and electrometallurgy.     

Use of isoperibolic calorimetry for the study of the effect of water concentration,temperature and reactor venting on the rate of hydroxylamine thermal decomposition

Hydroxylamine, NH₂OH, thermal decomposition has been responsible for two serious accidents. However, its reactive behavior and the synergy of factors affecting the rate of its decomposition are not understood. In this work, isoperibolic calorimetric measurements were performed in a metal reactor, in the temperature range 130–150 °C, employing 30–80 ml solutions containing 1.4–20 g of pure hydroxylamine (2.8–40 g of the supplied reagent). The calorimetric measurements were performed in order to assess the effects that NH₂OH concentration, temperature and reactor venting has on NH₂OH rate of decomposition. The measurements showed that increased concentration or temperature, results in faster reactions and probably higher pressure generation per mass of reactant, with concentration having a more pronounced effect. However, when both factors work synergistically the result is dramatically worse in terms of reaction rate. The pressure generation is also different, thus indicating that different reaction pathways predominate each time. Venting the produced gases in stages resulted in the highest mass loss of the solution.     

Construction safety: An analysis of systems failure: The case of the multifunctional Bos & Lommerplein estate,Amsterdam

Bos & Lommer is a district in the west of Amsterdam. The new centre, consisting of the district office, 96 apartments, a few dozen businesses and shops, a two-storey parking lot with capacity for more than 500 cars, and a market place, was completed in 2004. Less than 2 years later, in July 2006, this whole multifunctional complex had to be urgently cleared, because its safety could not be guaranteed.The investigations revealed that the planning and realisation of the Bos & Lommer complex were anything but exceptional. What happened there could have happened anywhere in the Netherlands and possibly elsewhere.This paper analyses the decision-making process in the planning and construction of the Bos & Lommerplein estate on the basis of accident causation theories. It will ascertain which safety science methodology is best equipped to describe and analyse the events in this multifunctional estate. The analysis forms the basis for a reflection on a set of concrete guidelines for designing and constructing complex projects. Construction safety would be enhanced if the scope for improvement in decision-making on complex building projects were properly utilised.     

Coordinating work in complex organizations

Differentiation, interdependence, and interest conflict between work units were investigated as determinants of managerial selection between coordination strategies. One hundred and four MBA students with managerial experience participated in a simulation in which they were required to select a strategy to manage systematically different relations between work units. Findings reveal a three-way interaction between differentiation, interdependence, and interest conflict affecting the degree of cooperation and centralization of selected strategies. The formalization of such strategies was affected by an interaction between differentiation and interest conflict. Implications for theory and practice are described.     

Speciation of arsenic in plants by HPLC-HG-AFS: extraction optimisation on CRM materials and application to cultivated samples

A recently developed method for the determination of arsenic species (arsenite, arsenate, monomethylarsonate, MMAA, and dimethylarsinate, DMAA) has been applied to the study of arsenic speciation in plants. This method uses ion-exchange liquid chromatography coupled on-line to atomic fluorescence spectrometry through continuous hydride generation. Various extraction procedures have been studied in detail using three plant certified reference materials. None of the procedures tested revealed fully satisfying results with all kinds of plant samples; microwave assisted extraction with 0.3 mol dm-3 orthophosphoric acid was found to be the most convenient for dealing with terrestrial plants. Species stability appears good. This method was applied to real world cultivated plant parts. Arsenate appears to predominate in soils, roots and leaves; unidentified species (probably arsenosugars) play an important role (60%) in rice fruits. Carrot was found to be the most contaminated edible plant part, containing 1 mg kg-1 essentially as arsenate species. MMAA was detected in all soils and some plant parts especially shallots at low levels, whereas DMAA was found only in one soil sample and in hot pepper leaves. Arsenite is a minor component of all soils; it is also present in some plant parts at low levels. However, no evident relationships were found between As speciation in the various plant parts and much more detailed studies will be necessary to elucidate As behaviour in plants.     

Glocalization of COVID-19 responses and management of the pandemic in Africa

ABSTRACT

The study explores how glocalization of COVID-19 responses affects the management of the pandemic in Africa. Using data from 20 selected African countries, the study found that the reliance on local medicines alongside other salient global initiatives for containment of COVID-19 is effective in managing the pandemic in Africa. It concluded that despite the high vulnerabilities of African countries to COVID-19, the glocal approach has yielded positive outcomes by increasing the number of patients that recover from COVID-19 and scaling down the fatalities compared with the other regions.