Analysis of dust distribution in silo during axial filling using computational fluid dynamics: Assessment on dust explosion likelihood

In this study, the dust distribution in a silo during axial filling was modelled using a commercial computational fluid dynamics (CFD) code. The work focused on the dust concentration distribution in the silo, for evaluating the likelihood of a dust explosion in the silo. The simulation was conducted using a combination of renormalized (RNG) k-epsilon and discrete phase models, with standard pressure interpolation and a second order upwind scheme. The predicted dust concentration distribution showed a good agreement with experimental data adopted from the literature. It was found that the dust concentration distribution was influenced by mean velocity and turbulence flow. The simulation results suggest that the cornstarch concentration inside the silo was always above the lower explosion limit (LEL), hence requiring a mitigating action or a control system to reduce the explosion risk.     

Enhanced styrene recovery from waste polystyrene pyrolysis using response surface methodology coupled with Box–Behnken design

A work applied response surface methodology coupled with Box–Behnken design (RSM-BBD) has been developed to enhance styrene recovery from waste polystyrene (WPS) through pyrolysis. The relationship between styrene yield and three selected operating parameters (i.e., temperature, heating rate, and carrier gas flow rate) was investigated. A second order polynomial equation was successfully built to describe the process and predict styrene yield under the study conditions. The factors identified as statistically significant to styrene production were: temperature, with a quadratic effect; heating rate, with a linear effect; carrier gas flow rate, with a quadratic effect; interaction between temperature and carrier gas flow rate; and interaction between heating rate and carrier gas flow rate. The optimum conditions for the current system were determined to be at a temperature range of 470–505 °C, a heating rate of 40 °C/min, and a carrier gas flow rate range of 115–140 mL/min. Under such conditions, 64.52% WPS was recovered as styrene, which was 12% more than the highest reported yield for reactors of similar size. It is concluded that RSM-BBD is an effective approach for yield optimization of styrene recovery from WPS pyrolysis.     

Photo- and electro-catalysis for solar disinfection of Escherichia coli-contaminated water using Ag–TiO2/graphite

A titanium dioxide film on a graphite substrate was synthesized by chemical bath deposition from TiCl₄ as precursor and with the surfactant cetyl trimethyl ammonium bromide as a linking and assembling agent. Silver was loaded on the TiO₂ film by electrodeposition at 0.025?A. Water contaminated with Escherichia coli was disinfected under sunlight irradiation by photolysis (Lys), photocatalysis (PC), photoelectrocatalysis (PEC), and electrocatalysis (EC). The highest rate constant, k, was achieved with EC; k was 5.1?×?10^?2 colony forming units (CFU) mL^?1?min^?1. However, auto-oxidation of Ag occurred during EC and PEC. Meanwhile, the rate constant of disinfection by means of PC was lower than EC and PEC, and k was 3.82?×?10^?2 CFU?mL^?1?min^?1. Nevertheless, the auto-oxidation of Ag in the Ag–TiO₂/graphite tablet did not occur during the disinfection process.     

Assessing the costs for adaptation of marine constructions to sea-level rise

Marine constructions are highly vulnerable to climate change and sea-level rise (SLR), leading to increased risk rates of destruction and the potential closure of ports, harbors, and marinas along the coast. We present a cost-adjustment analysis for such constructions along the south-eastern Mediterranean coast, which takes into account the physical characteristics of the constructions, and environmental uncertainty factors. At 0.5 m SLR, the estimated adjustment cost is USD 280 million, and at 1 m SLR, the estimated cost is USD 505 million. These costs are equivalent to 0.091% and 0.165% of the Israeli gross domestic production, respectively. Although high, these adjustment costs are lower than the costs of future damage that will accrue if we fail to act. This implies that the adaptation-policy approach to controlling for the risk of SLR will provide benefits to the economic marine sectors and the public at large.     

Seven years from the first application of polyaluminium chloride in the Czech Republic – effects on phytoplankton communities in three water bodies

This study determines the efficiency of polyaluminium chloride application on phytoplankton species as a consequence of five reservoir restorations in the Czech Republic during the years 2005 and 2008, including the first ever large-scale application. Although polyaluminium chloride has been used in water treatment plants across the world, information about its application toward cyanobacterial blooms in nature is poor. Although the application of polyaluminium chloride did not cause any fundamental long-term changes in the composition of phytoplankton species or phosphorus load, instead causing fast and acute removal of the phytoplankton community, it may act as an algicidal compound with fast removal efficiency. All treated water bodies described in our study remained unaffected by cyanobacterial blooms and the hygienic limit for the purposes of recreation was not exceeded in any particular season. This article should serve as notice of the advantages and disadvantages of polyaluminium chloride application, and also warn against the uniform usage of this chemical as a method of reducing phytoplankton species in all types of water bodies where cyanobacteria are present. Moreover, data about the effects on non-target (invertebrates) species and microcystin release from cyanobacterial cells are also mentioned.     

The use of cost–benefit analysis in environmental policies: Some issues raised by the Water Framework Directive implementation in France

This paper aims to practically contribute to the literature on the use of cost–benefit analysis (CBA) and economic evaluation in environmental decision-making through a practical case study: the implementation of the Water Framework Directive (WFD) in France, for the first cycle (2010–2015). The WFD requires that Member States achieve “good status” for all water bodies in 2015. However, exemptions can apply, if justified, on natural, technical or economic reasons. For the latter, EU guidance documents recommend to use CBA. In France, the water agencies carried out 710 CBAs on proposed restoration projects for water bodies. This article reports on this experience. Issues concerning these analyses are discussed, especially the assessment of non-market benefits. Finally, this article questions the use of economic analysis in the implementation of environmental policy.     

What makes institutional crafting successful? Applying the SES to case studies from India and the greater Mekong Region

Using two very different empirical settings, this paper emphasizes the required conditions for the successful crafting of sustainable institutions. In the first setting, different farmer groups in Cambodia and Vietnam try to establish a collective approach for small-scale community-based aquaculture and fail. In the second setting, the collective initiatives of urban women in India are analysed. The Indian women succeed in their objective of a fuel transition from firewood to gas cookers using a cooperative approach. Ostrom's variables identified in the “Multitier Framework for Analyzing Social–Ecological Systems (SES)” (Ostrom, 2007) are applied to local collective action initiatives in both settings to understand which factors make some of the groups succeed in their objectives and others fail. This research highlights the complexity as well as the uniqueness of different SESs. At the same time, the paper contributes to demonstrating the usability of the SES and certain variables to estimate the likelihood of success of self-organisation and crafting of rules. It highlights the relevance of certain conceptual variables for sustainable or unsustainable outcomes for different cases.     

Insights into the pathophysiology of twin–twin transfusion syndrome

Twin–twin transfusion syndrome (TTTS) is attributed to trans-anastomotic transfusion between twins. Anastomoses are ubiquitous in monochorionic (MC) placentae, yet TTTS develops in only 15%. Although ex vivo and in vivo studies fail to identify a unique anastomotic signature, TTTS placentae are typically associated with an imbalance in unidirectional arteriovenous anastomoses with absent bidirectional anastomoses. Doppler detection of an artery-artery anastomosis reduces the chance of TTTS, whereas, in those that develop the disease, it improves stage-independent survival. Selective laser is often curative, but an increasingly recognized risk of persistent or reverse TTTS may be attributable to atypical arteriovenous anastomoses not identifiable from the chorionic plate. Simple dysvolaemia fails to explain several phenotypic features, including haematological concordancy, recipient hypertension, and reversibly absent end diastolic flow in the donor. The renin-angiotensin system is upregulated in the donor and downregulated in the recipient's kidneys, while paradoxically raised renin levels in the recipient may contribute to raised afterload along with endothelin. Although research is limited in humans by therapy and the lack of a suitable experimental model, further studies of placental and vascular pathophysiology may not only refine current treatment modalities but may also, in addition, suggest further avenues for downstream management such as genetic predisposition testing or pharmacological intervention. Copyright © 2005 John Wiley & Sons, Ltd.