Fume emissions during gas metal arc welding

The control of exposure to welding fumes is of increasing importance in promoting a healthy, safe and productive work environment. This article describes the effects of shielding gas composition on the amount and composition of welding fumes produced during gas metal arc welding (GMAW). The amount of fumes generated during welding was measured for steady current over a range of wire-feed speeds and arc voltages using the standard procedures contained in ANSI/AWS F1.2 [American Welding Society. ANSI/AWS F1.2. Laboratory method for measuring fume generation rates and total fume emission of welding and allied processes. Miami, Florida; 1992]. Results of these measurements show that the fume formation rates (FFRs) increase with CO₂ and O₂ in the shielding gas mixture. The lowest FFRs were obtained with the mixtures of Ar?+?2%CO₂ and Ar?+?3%CO₂?+?1%O₂. The highest FFRs were obtained with the mixtures of Ar?+?18%CO₂ and Ar?+?5%CO₂?+?4%O₂. The welding fumes contains mainly iron, manganese, silicon, titanium and sodium under oxide forms. The fume cluster particles have dimensions between 0.5 and 2?µm. The FFR was found to be governed by the transfer modes of molten metal, i.e. the current intensity and arc voltage, as well as by the shielding gas mixtures composition. Thus these parameters have to be taken into consideration before designing a welding process. Whenever possible, users of GMAW should use the lowest current intensity. However, when this is not possible, due to the constraints of process productivity, welders should use higher currents, but with Ar?+?2%CO₂ and Ar?+?3%CO₂?+?1%O₂ shielding mixtures, which will lead to smaller fume emissions.     

Flood-risk mapping for storm surge and tsunami at Cocos Bay (Manzanilla), Trinidad

Cocos Bay is a barrier beach under threat of marine erosion from the high energy environment of the Atlantic Ocean. This barrier beach borders the Ramsar listed Nariva Swamp, and helps maintain its delicate wetland ecosystem, however, ongoing coastal erosion at this beach threatens the longevity of this freshwater wetland. Due to the geographical location of Cocos Bay being exposed to Atlantic generated storm events and the low relief of the study area, there is a potential threat of storm surges breaching the barrier beach. Owing to the geological setting of the region (located in an active seismic province with earthquakes, volcanicity and landslides), there also exists the threat of tsunamis. This paper is a GIS simulation of the area extent of inundation and the affected infrastructure from such events. It utilizes a DEM and land-use to quantifying inundation areas, and the extent of vulnerability of various elements. The low relief of the barrier beach renders the area extremely vulnerable from events that trigger sea level increases. Simulations revealed that as little as a 1 m storm surge has the potential to disrupt the Nariva Swamp and threaten coastal infrastructure while higher storm surges and tsunamis have the potential to decimate the entire area. The flood-risk model generated indicates a very high vulnerability to storm surges, along the entire length of the coastline. These results have implications for future development and sustainable management of this ecologically sensitive area.     

Sustainability measurement of product-service systems: Brazilian case studies about electric car-sharing

Modifying the traditional production system and the culture of consumption is necessary to achieve a sustainable society. The product-service system (PSS) business model allows companies to progressively add services to physical products, thus promoting more pro-sustainable business outcomes. The purpose of this work is to verify how a PSS model can contribute to sustainability by analyzing two electric car-sharing projects using a set of five factors. As a methodological strategy, a Systematic Literature Review and a case study of the two projects (VAMO and EMOTIVE) were performed. Findings show benefits generated by both projects as to environmental aspects, mainly related to gases emission. It was also possible to observe social benefits due to income development and environmental awareness. This paper thus contributes to the discussion of the potential of the PSS models and how they can leverage business models toward a more sustainable society. Although the results are applicable only in this case, this article can motivate new projects and contribute to enriching the debate about sustainable solutions, as the literature in this field still provides few case studies showing these types of applications.     

Novel Whey Protein Isolate/Polyvinyl Biocomposite for Packaging: Improvement of Mechanical and Water Barrier Properties by Incorporation of Nano-silica

Journal of Polymers and the Environment - The current global proposal for withdrawing polymers with high resistance to degradation and from fossil sources from disposable appliances, as well as the...     

Red blood cell osmotic fragility in the Spanish mackerel Scomberomorus maculatus

Red cell osmotic fragility was studied in 50 blood samples of the fish Scomberomorus maculatus (Mitchill). High levels of mean corpuscular fragility were found and hypotheses are presented to explain this phenomenon.     

FOG AND ACIDIFICATION IMPACTS ON ION BUDGETS OF BASINS IN NOVA SCOTIA,CANADA1

ABSTRACT: We examined hydrogeochemical records for a dozen watersheds in and near Kejimkujik National Park in southwestern Nova Scotia by relating stream ion concentrations and fluxes to atmospheric deposition, stream type (lake inlet versus outlet; brown versus clear water), and watershed type (catchment area, topography, soils, and dominant forest cover type). We found that fog and dry deposition make important contributions to S, N, Cl, H, Ca, Mg, K, and Na inputs into these watersheds. Seasalt chloride deposition from rain, snow, fog, and dry deposition equal total stream outputs on a region‐wide basis. Chloride outputs, however, differ among watersheds by a factor of about two, likely due to local differences in air flow and vegetational fog interception. We found that most of the incoming N is absorbed by the vegetation, as stream water NO3^‐ and NH4⁺ are very low. Our results also show that the vegetation and the soils absorb about half of the incoming SO4². In comparison with other North American watersheds with similar forest vegetation, Ca outputs are low, while Mg and K outputs are similar to other regions. Soil exchangeable Ca and soil cation exchange capacity are also very low. We found that first‐order forest streams with no upstream lakes have a distinct seasonal pattern that neither corresponds with the seasonal pattern of atmospheric deposition, nor with the seasonal pattern of downstream lake outlets.     

Physiological responses and phytoremediation capacity of floating and submerged aquatic macrophytes exposed to ciprofloxacin

Environmental Science and Pollution Research - Ciprofloxacin (Cipro) water contamination is a global concern, having reached disturbing concentrations and threatening the aquatic ecosystems. We...     

Analysis of potentially toxic metal constraints to apply sewage sludge in Portuguese agricultural soils

Environmental Science and Pollution Research - The application of sewage sludge (SS) in the soil can be a valuable way to increase its content of organic matter. However, the concentration of...     

Suitable environmental areas for commercial timber in the state of Rio de Janeiro,Southeastern Brazil

Environment, Development and Sustainability - In state of Rio de Janeiro, the Southeast Region of Brazil, 97.91% of the reforested areas contain exclusively species of Pinus and Eucalyptus. Due to...