Simple Arrhenius-type function accurately predicts dissolved oxygen saturation concentrations in aquatic systems

A sufficient supply of dissolved oxygen (DO) is vital for life in higher organisms. In aquatic systems, oxygen regulates respiratory metabolism, mediates biogeochemical cycles, and is an integral component of water quality. In this work, a simple predictive tool for dissolved oxygen saturation concentrations in aquatic systems as a function of chloride concentration and temperature using a novel Arrhenius-type asymptotic exponential function has been formulated. The proposed method predicts the amount of dissolved oxygen saturation concentrations for temperatures up to 50 °C and chloride concentrations up to 25 g/l. Estimations are found to be in excellent agreement with the reliable data in the literature with average absolute deviation being 3%. The tool developed in this study can be of immense practical value for the engineers and scientists to have a quick check on the oxygen saturation concentrations in aquatic systems at various conditions without opting for any experimental measurements. In particular, environmental science experts would find the proposed approach to be user-friendly with transparent calculations involving no complex expressions.     

Effect of pressure on the hydropyrolysis of Jatropha seed deoiled cake

The necessity to move towards a sustainable economy is increasing day by day owing to various problems like climate change, increasing crude oil prices, etc. In this line, hydropyrolysis of Jatropha seed deoiled cake has been carried out at various pressures of hydrogen (1, 20, 40 and 52 bar) at 450 °C. With an increase in pressure under the experimental conditions of present study from 1 to 40 bar, the yield of bio-oil is found to have increased and beyond 40 bar the bio-oil yields have decreased. It has been observed that the liquid bio-oil yield is highest at 17 wt% at 40 bar. The FTIR spectrum of the bio-oil and char at 40 bar shows maximum functionality, indicating the clear opening of the macromolecular structure. The EDAX analysis of the hydropyrolysis char obtained at 40 bar pressure show a maximum of 85 wt% carbon and minimum of oxygen 13 wt%.     

Developing biofuels industry in small economies: Policy experiences and lessons from the caribbean basin initiative

With increasing concerns about rising energy demand and cost, diminishing oil reserves, and climate change, Central American and Caribbean (CAC) nations have the opportunity to become producers of low-carbon sustainable biofuels for domestic consumption and foreign exchange earnings. While the region has a number of comparative advantages for developing a vibrant biofuels sector, including favorable climate and significant agricultural experience, the experience under the favorable Caribbean Basin Initiative (CBI) has exposed significant technical and non-technical barriers that must be overcome. Using information compiled through interviews with industry executives, government policy makers and civil society stakeholders, we provide a critical analysis of this experience focusing on non-technical barriers to investment. Survey results suggest that political uncertainty, poor regulatory frameworks, and lack of institutional commitment and business incentives are the main non-technical barriers. Having laid out the challenges, we propose potential policy positions to stimulate growth of the regional biofuels sector. Results point to the need to prioritize enhancing national legislation, developing risk prevention plans, creating supply and demand side incentives and increasing multilateral collaboration. While these findings are derived from the Caribbean Basin experience, they may also be applicable to small economies in other regions that are considering policies for biofuels industry development.     

An Analysis of the Yearly Changes in Sulfur Concentrations at Various National Parks in the United States, 1980-1996

ABSTRACT

An apparent increasing trend in the summer concentrations of particulate sulfur at Shenandoah (for the time period 1982-1995) and at Great Smoky Mountains (for the time period 1984-1995) has been pointed out by some researchers. Others have suggested that these increasing trends may be an analytical artifact resulting from the switch from the Stacked Filter Units (SFU) measurement system to the IMPROVE (Interagency Monitoring of Protected Visual Environments) measurement system that occurred during the winter of 1987. To obtain a better understanding of the effect of the protocol change, we investigate the changes in the seasonal averages of sulfur concentrations for successive pairs of years for the period 1980-1996 for about 20 national park sites in the United States. For the period 1980-1987, we use sulfur data from the old (SFU) database and for the period 1988-1996, we use the IMPROVE database. Changes from one year to the next similar to that between 1987 and 1988 occurred during other years and seasons suggesting that chance causes alone could perhaps explain it, the degree to which chance could have caused the changes was measured using the permutation test for matched. At the very least, additional information such as side by side readings using SFU and IMPROVE measurement methods, may be needed to better understand any systematic effect in the sulfur measurements that may be ascribable to the protocol change.     

Developing a predictive understanding of landscape importance to the Punan-Pelancau of East Kalimantan, Borneo

In order for local community views to be incorporated into new development initiatives, their perceptions need to be clearly understood and documented in a format that is readily accessible to planners and developers. The current study sought to develop a predictive understanding of how the Punan Pelancau community, living in a forested landscape in East Kalimantan, assigns importance to its surrounding landscapes and to present these perceptions in the form of maps. The approach entailed the iterative use of a combination of participatory community evaluation methods and more formal modeling and geographic information system techniques. Results suggest that landscape importance is largely dictated by potential benefits, such as inputs to production, health, and houses. Neither land types nor distance were good predictors of landscape importance. The grid-cell method, developed as part of the study, appears to offer a simple technique to capture and present the knowledge of local communities, even where their relationship to the land is highly complex, as was the case for this particular community.     

Evaluation of antifouling activity of eight commercially available organic chemicals against the early foulers marine bacteria and Ulva spores

Environmental impacts caused by tin and copper based commercial antifouling (AF) paints were proved to be detrimental to aquatic ecosystems. Therefore, a search of environmental friendly AF compounds to be used in marine paint to protect the surface of maritime developmental structures from the unwanted biofouling is a burning issue of the present time. Commercially available eight organic chemicals--allyl isothiocyanate, beta-myrecene, cis-3-hexenyl acetate, citral, ethyl heptanoate, eugenol, methyl caproate, and octyl alcohol were evaluated forAF activities using both laboratory and field assays. The test chemicals were found to repel the target motile marine bacteria--Alteromonas marina, Bacillus atrophaeus, Roseobactergallaeciensis and Shewanella oneidensis and motile spores of the green alga, Ulva pertusa. The bacterial and Ulva spore repulsion activities of the test chemicals were measured by chemotaxis and agar diffusion methods respectively interestingly these test chemicals were less toxic to the test fouling species. The toxicity of the test chemicals was measured by using antibiotic assay disks against the bacteria and motility test against Ulva spores. Moreover, in field assay, all test chemicals showed a perfect performance ofAF activity showing no fouling during the experimental period of one year Such results and commercial as well as technical feasibility of the test chemicals firmly showed the possibility of using as alternatives of the existing toxic AF agents.     

Do the poor have what they need to adapt to climate change? A case study of Nepal

Nepal's geographical landscape of plains, hills, and mountains exposes it to severe climatic conditions. Out of the three regions, the plain, also called Terai, has the greatest risk of flooding, especially during the monsoon season when heavy precipitation coincides with snow and glacier melting from the mountains and hills. In recent years, greater water availability has increased the frequency of flooding, destroying farms, livestock, and infrastructure, hence, reducing agricultural productivity and disrupting economic activities. What makes Nepal a unique case study for climate change is its richness in water resources, propensity to flood, the percentage of poor people living in the flood prone region, and their dependency on natural resources. The lessons drawn can help when formulating pro-poor adaptation policies for other Asian and many developing countries that are as diverse, poor, and agrarian as Nepal. Using data collected through survey interviews, the study examines the ability of the poor to adapt to climate change. The study also explores the adaptive capacity of communities in the Koshi Tappu area, by examining whether or not they have the required capital assets (human, social, natural, physical, and financial capital) to remain resilient in the face of continuous climate events impacts.     

Impacts of vineyard area dynamics on soil erosion in a Mediterranean catchment (1950-2011)

The Mediterranean basin has undergone widespread land cover change. Urbanization of coastal areas, land abandonment of steeper slopes, and agricultural intensification in alluvial plains are recurrent themes. The objective of this study was to examine how vineyard land cover changes have affected agricultural soil erosion in a 50 year period (1950–2011). The study area covers a 235 km² catchment located near the Gulf of St Tropez. Aerial photographs were used to map land cover in 1950, 1982, 2003 and 2011, and the RUSLE soil erosion model was run to estimate soil erosion.

Between 1950 and 2011, vineyard went from about 2,426 ha to 1,561 ha. Mean soil erosion increased as vineyard slopes became steeper (11.8 T ha^?1, 13.2 T ha^?1, 14.4 T ha^?1 and 13.5 T ha^?1 for 1950, 1982, 2003 and 2011). Total erosion decreased after 1982: 28,621 T y^?1 in 1950, 29,030 T y^?1 in 1982, 22,848 T y^?1 in 2003, and 21,074 T y^?1 in 2011. Total soil loss in 2011 is about 75% of values in 1950–1982, so impacts on water pollution and channel dredging have evolved positively over time.     

Nitrous oxide emissions in nonflooding period from fallow paddy fields

The study was conducted to investigate the N2O emissions and dissolved N2O in the leachate during the nonflooding period in nongrowing paddy fields.Three kinds of paddy soils were repacked to soil columns and were supersaturated with water initially and dried gradually in a greenhouse to attain the N2O emissions flux during the incubation.Soils with the texture of silty clay-loam (Q and H) produced cracks during the drying of soil,but soil with the texture of silty loam (X) did not form the cracks.Cracked s...     

New method accurately predicts carbon dioxide equilibrium adsorption isotherms

Among the methods that are being developed to date for CO₂ capture and separation, carbon dioxide adsorption is of great interest due to its low energy consumption, low equipment cost and easiness for application. In this work, a simple method which is easier than existing approaches requiring more complicated and longer computations is presented to accurately predict the carbon dioxide adsorption isotherms for a microporous material as a function of temperature and partial pressure of carbon dioxide. The method appears promising and can be extended for CO₂ capture as well as for separation of wide range of adsorbents and microporous materials including several molecular sieves merely by the quick readjustment of tuned coefficients. The proposed method showed consistently accurate results across the proposed pressure and temperature ranges. Predictions showed an average absolute deviation of 1.4% compared to existing Sips and Langmuir equations which show an average absolute deviations of 2.3% and 4%, respectively. The proposed method is superior owing to its accuracy and clear numerical background, wherein the relevant coefficients can be retuned quickly for various cases. This simple-to-use approach can be of immense practical value for the engineers and scientists to have a quick check on adsorption capacities of a given adsorbent at various temperatures and pressures without the necessity of any experimental measurements. In particular, personnel dealing with regulatory bodies of greenhouse gas control and process industries would find the proposed approach to be user friendly involving transparent calculations with no complex expressions.