Studies on process optimization of biodiesel production from waste cooking and palm oil

This work investigated the optimisation of biodiesel production from waste cooking oil (WCO) and palm oil using a two-step transesterification process for WCO and base catalysed transesterification for palm oil. Transesterification reactions were carried out to investigate the effects of prepared catalyst CaO, methanol/WCO and methanol/palm oil ratio and temperature on the yield of biodiesel. A series of experiments were conducted to determine the best conditions for biodiesel production, using methanol/oil ratio between 4:1 and 11:1 and contact time varying between 2 and 4 h. Biodiesel yield of around 90 and 70% was obtained for palm and waste cooking oil at the methanol/oil ratios of 6:1 and 8:1 at temperature of 60 °C for reaction time of 4 h using prepared CaO as catalyst. The physicochemical properties of palm and WCO biodiesel were carried out using standard methods, while the fatty acid profile was determined using gas chromatography. The investigation concludes that biodiesel obtained from palm and waste cooking oil was within the specified limit.     

Survival of Porcine Reproductive and Respiratory Syndrome Virus in Pork Products

There is a risk of virus transmission through contaminated pork, and many viruses are considered potential hazards for both humans and livestock. The risk of transmission may be elevated with importation/exportation of meat between countries globally. Survival of porcine reproductive and respiratory syndrome virus (PRRSV) in different pork products has not been studied. The present study evaluated PRRSV survival in four different products: fresh sausage, ham, bacon, and acidified sausage prepared with experimentally contaminated pork. These products were prepared according to standard methods used by the manufacturers of pork products, and then stored at room temperature, 4 °C and ?20 °C. PRRSV was detected only in fresh sausage for up to 15 days at 4 °C and for 30 days at ?20 °C. No PRRSV was detected at any temperature in any of the other three products. These preliminary data provide valuable information for the pork processing industry, as well as in planning for import/export of these products among different countries.     

Atmospheric ozone: formation and effects on vegetation

Ozone (O(3)) is present both in the troposphere and the stratosphere. Troposphere O(3) is predominantly produced by photochemical reactions involving precursors generated by natural processes and to a much larger extent by man's activities. There is evidence for a trend towards increasing tropospheric O(3) concentrations. However, tropospheric O(3) is known to account for only 10% of the vertical O(3) column above the earth's surface. The stratosphere accounts for an additional 90% of the O(3) column. There is evidence to suggest that there are losses in the stratospheric O(3) due to the updraft of O(3) destroying pollutants generated by both natural processes and by human activity. Such a loss in stratospheric O(3) can result in alterations of incidence in the ultraviolet (UV) radiation to the earth's surface. Tropospheric O(3) is known to be highly phytotoxic. Appropriate exposures to O(3) can result in both acute (symptomatic) and chronic (changes in growth, yield or productivity and quality) effects. Chronic effects are of great concern in terms of both crops and forests. A number of experimental techniques are available to evaluate the chronic effects of O(3) on plants. There are limitations attached to the use of these techniques. However, results obtained, with such techniques are valuable if interpreted in the appropriate context. Among all field evaluation techniques, open-top chambers are the most frequently used method for evaluating the chronic effects of O(3) on crops. The National Crop Loss Assessment Program (NCLAN) of the United States is the largest such effort. However, given the limitations of the open-top chambers and the experimental aspects of NCLAN, its results must be interpreted with caution. On the other hand, acute effects can be evaluated with less complexity through the use of biological indicator plants. The numerical modelling of such effects are also far less complicated than establishing numerical cause and effects relationships for chronic effects. Confounding the acute or chronic responses of plants to O(3), is the presence of other kinds and forms of pollutants in the ambient atmosphere and the incidence of pathogens and pests. The resulting complex interactions and joint effects on plants are poorly understood. Future research must address these issues. In the final analysis we have re-emphasized the fact that plant health is the product of its interaction with the physical and chemical climatology and pathogens and pests. What we have described in this context is the importance of tropospheric O(3) within the chemical climatology of our environment and its effects on vegetation.     

Application of spectral coherence analysis to describe the relationships between ambient ozone exposure and crop growth

Growth season-based time series spectral coherence analysis was performed between weekly changes in hourly ambient O(3) concentrations and weekly changes in alfalfa height growth. Weekly median hourly O(3) concentration and the corresponding weekly cumulative integral (sum of all hourly concentrations within the week) were used as indicators of weekly O(3) spectral density and coherence with the change in weekly alfalfa height growth. In general, the weekly cumulative integral performed much better than the weekly median O(3) concentration. A conceptual analysis of the results is presented, along with a recommendation that crop growth stage-based cumulative integrals merit further evaluation towards a better understanding of cause-effect relationships.     

Background culturable bacteria aerosol in two large public buildings using HVAC filters as long term, passive, high-volume air samplers

Background culturable bacteria aerosols were collected and identified in two large public buildings located in Minneapolis, Minnesota and Seattle, Washington over a period of 5 months and 3 months, respectively. The installed particulate air filters in the ventilation systems were used as the aerosol sampling devices at each location. Both pre and final filters were collected from four air handing units at each site to determine the influence of location within the building, time of year, geographical location and difference between indoor and outdoor air. Sections of each loaded filter were eluted with 10 ml of phosphate buffered saline (PBS). The resulting solutions were cultured on blood agar plates and incubated for 24 h at 36 degrees C. Various types of growth media were then used for subculturing, followed by categorization using a BioLog MicroStation (Biolog, Hayward, CA, USA) and manual observation. Environmental parameters were gathered near each filter by the embedded on-site environmental monitoring systems to determine the effect of temperature, humidity and air flow. Thirty nine different species of bacteria were identified, 17 found only in Minneapolis and 5 only in Seattle. The hardy spore-forming genus Bacillus was the most commonly identified and showed the highest concentrations. A significant decrease in the number of species and their concentration occurred in the Minneapolis air handling unit supplying 100% outdoor air in winter, however no significant correlations between bacteria concentration and environmental parameters were found.     

Assessment of the effects of municipal sewage,immersed idols and boating on the heavy metal and other elemental pollution of surface water of the eutrophic Hussainsagar Lake (Hyderabad,India)

The surface water qualities of Hussainsagar, an eutrophic urban lake in the midst of twin cities of Hyderabad and Secunderabad (India) receiving large quantities of external inputs—both untreated municipal sewage containing industrial effluents, and treated sewage, a large number of annually immersed idols of God and Goddess, and intense boating activities were assessed in relation to the concentration of elements including heavy metals of the water along the necklace road of the lake. Elemental analyses of water using ICP-MS revealed 26 elements including heavy metals—As, Cd, Cr, Ni, Pb, Cu, Fe, Mn, Se, Ba, Zn, Mo, V, Co, Ag, Sr, Rb, Mg, K, Ca, Al, Si, Sb, Na, Li, and B, in the surface water of the lake. Of these, the first 15 elements were found in elevated concentrations in the water at the outfall point of the untreated municipal sewage (site 3), which was the main dominating source of contamination of the lake water while Cu and Sb were recorded in higher concentrations at the outfall of treated effluent from Sewage Treatment Plant, and three elements (Ba, Si, and B) were in higher concentration at the sites of outfall of sewage flowing from an oxygenated pond (site 4), Ca, Zn, and Sr, at the site immersed with idols (site 1), and Pb, Ag, and Al at the center of the lake (site 5) with intense boating activities. Concentrations of most of these elements exceeded the maximum permissible limits of national (Indian Council Medical Research) standards for drinking water. The concentrations of most of the elemental contaminants showed significant positive correlations between them.     

Uncertainties in the current knowledge of some atmospheric trace gases associated with U.S. agriculture: a review

Approximately 80 different crop species are grown in the United States in widely differing geographic areas, climatic and edaphic conditions, and management practices. Although the majority of cultivated acreage in the United States is planted with only about 10 primary crops, uncertainties associated with trace gas emissions arise from: (1) limited data availability, (2) inaccurate estimates because of large temporal and spatial variability in trace gas composition and magnitude of trace gas emissions from agricultural activities, (3) differing characteristics of pollutant emissions from highly dispersed animal feed-lots, and (4) limited understanding of the emissions of semi-volatile organic compounds (SVOCs) associated with agriculture. Although emission issues are of concern, so also is atmospheric deposition to cropping systems, including wet and dry nitrogen, minerals, and organic compounds. These can have feedback effects on trace gas emissions. Overall, the many gaps in our understanding of these aspects of agricultural systems deserve serious attention.     

Forest responses to tropospheric ozone and global climate change: an analysis

In this paper an analysis is provided on: what we know, what we need to know, and what we need to do, to further our understanding of the relationships between tropospheric ozone (O(3)), global climate change and forest responses. The relationships between global geographic distributions of forest ecosystems and potential geographic regions of high photochemical smog by the year 2025 AD are described. While the emphasis is on the effects of tropospheric O(3) on forest ecosystems, discussion is presented to understand such effects in the context of global climate change. One particular strong point of this paper is the audit of published surface O(3) data by photochemical smog region that reveals important forest/woodland geographic regions where little or no O(3) data exist even though the potential threat to forests in those regions appears to be large. The concepts and considerations relevant to the examination of ecosystem responses as a whole, rather than simply tree stands alone are reviewed. A brief argument is provided to stimulate the modification of the concept of simple cause and effect relationships in viewing total ecosystems. Our knowledge of O(3) exposure and its effects on the energy, nutrient and hydrological flow within the ecosystem are described. Modeling strategies for such systems are reviewed. A discussion of responses of forests to potential multiple climatic changes is provided. An important concept in this paper is that changes in water exchange processes throughout the hydrological cycle can be used as early warning indicators of forest responses to O(3). Another strength of this paper is the integration of information on structural and functional processes of ecosystems and their responses to O(3). An admitted weakness of this analysis is that the information on integrated ecosystem responses is based overwhelmingly on the San Bernardino Forest ecosystem research program of the 1970s because of a lack of similar studies. In the final analysis, it is recommended that systems ecology be applied in examining the joint effects of O(3), carbon dioxide and ultraviolet-B radiation on forest ecosystems.     

An analysis of numerical models of air pollutant exposure and vegetation response

A number of empirical (statistical, regression oriented) and mechanistic (process oriented) models are presently available to examine the relationship between air pollution stress and plant response. These models have their strengths and weaknesses. In all these models, a major concern is the numerical definition of the pollutant exposure kinetics (dose). At present there are no numerical definitions of dose which make satisfactory biological sense. A key issue is the existence of a biological time clock where plants respond differently to the pollutant stress at different stages of their growth. On the other hand, policy makers and regulatory personnel prefer a simple approach which would facilitate implementation and administration of ambient air quality standards. Long-term air pollutant averaging techniques create artifacts due to the non-normal distribution of ambient concentrations. A more appropriate approach may be the use of 'median' and 'percentiles' computed from short duration pollutant concentrations. Such an approach would be free of the influence of the non-normal distribution, but would require the development of appropriate exposure-response models. Any transfer of results from unit level models to regional level leads to 'scaling error'. There is no general agreement among researchers on how to deal with the scale problem. While this situation persists, any policy formulated on regional impact assessment must acknowledge the uncertainty.