870 resultados para Oils
Resumo:
Biodiesel is a renewable fuel that has been shown to reduce many exhaust emissions, except oxides of nitrogen (NOx), in diesel engine cars. This is of special concern in inner urban areas that are subject to strict environmental regulations, such as EURO norms. Also, the use of pure biodiesel (B100) is inhibited because of its higher NOx emissions compared to petroleum diesel fuel. The aim of this present work is to investigate the effect of the iodine value and cetane number of various biodiesel fuels obtained from different feed stocks on the combustion and NOx emission characteristics of a direct injection (DI) diesel engine. The biodiesel fuels were chosen from various feed stocks such as coconut, palm kernel, mahua (Madhuca indica), pongamia pinnata, jatropha curcas, rice bran, and sesame seed oils. The experimental results show an approximately linear relationship between iodine value and NOx emissions. The biodiesels obtained from coconut and palm kernel showed lower NOx levels than diesel, but other biodiesels showed an increase in NOx. It was observed that the nature of the fatty acids of the biodiesel fuels had a significant influence on the NOx emissions. Also, the cetane numbers of the biodiesel fuels are affected both premixed combustion and the combustion rate, which further affected the amount of NOx formation. It was concluded that NOx emissions are influenced by many parameters of biodiesel fuels, particularly the iodine value and cetane number.
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Vehicular traffic in urban areas may adversely affect urban water quality through the build-up of traffic generated semi and non volatile organic compounds (SVOCs and NVOCs) on road surfaces. The characterisation of the build-up processes is the key to developing mitigation measures for the removal of such pollutants from urban stormwater. An in-depth analysis of the build-up of SVOCs and NVOCs was undertaken in the Gold Coast region in Australia. Principal Component Analysis (PCA) and Multicriteria Decision tools such as PROMETHEE and GAIA were employed to understand the SVOC and NVOC build-up under combined traffic scenarios of low, moderate, and high traffic in different land uses. It was found that congestion in the commercial areas and use of lubricants and motor oils in the industrial areas were the main sources of SVOCs and NVOCs on urban roads, respectively. The contribution from residential areas to the build-up of such pollutants was hardly noticeable. It was also revealed through this investigation that the target SVOCs and NVOCs were mainly attached to particulate fractions of 75 to 300 µm whilst the redistribution of coarse fractions due to vehicle activity mainly occurred in the >300 µm size range. Lastly, under combined traffic scenario, moderate traffic with average daily traffic ranging from 2300 to 5900 and average congestion of 0.47 was found to dominate SVOC and NVOC build-up on roads.
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In this study on the basis of lab data and available resources in Bangladesh, feasibility study has been carried out for pyrolysis process converting solid tire wastes into pyrolysis oils, solid char and gases. The process considered for detailed analysis was fixed-bed fire-tube heating pyrolysis reactor system. The comparative techno-economic assessment was carried out in US$ for three different sizes plants: medium commercial scale (144 tons/day), small commercial scale (36 tons/day), pilot scale (3.6 tons/day). The assessment showed that medium commercial scale plant was economically feasible, with the lowest unit production cost than small commercial and pilot scale plants for the production of crude pyrolysis oil that could be used as boiler fuel oil and for the production of upgraded liquid-products.
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Food modelling systems such as the Core Foods and the Australian Guide to Healthy Eating are frequently used as nutritional assessment tools for menus in ‘well’ groups (such as boarding schools, prisons and mental health facilities), with the draft Foundation and Total Diets (FATD) the latest revision. The aim of this paper is to apply the FATD to an assessment of food provision in a long stay, ‘well’, group setting to determine its usefulness as a tool. A detailed menu review was conducted in a 1000 bed male prison, including verification of all recipes. Full diet histories were collected on 106 prisoners which included foods consumed from the menu and self funded snacks. Both the menu and diet histories were analysed according to core foods, with recipes used to assist in quantification of mixed dishes. Comparison was made of average core foods with Foundation Diet recommendations (FDR) for males. Results showed that the standard menu provided sufficient quantity for 8 of 13 FDRs, however was low in nuts, legumes, refined cereals and marginally low in fruits and orange vegetables. The average prisoner diet achieved 9 of 13 FDRs, notably with margarines and oils less than half and legumes one seventh of recommended. Overall, although the menu and prisoner diets could easily be assessed using the FDRs, it was not consistent with recommendations. In long stay settings other Nutrient Reference Values not modelled in the FATDS need consideration, in particular, Suggested Dietary Targets and professional judgement is required in interpretation.
Resumo:
The conversion of biomass waste in the form of date seed into pyrolysis oil by fixed bed pyrolysis reactor has been taken into consideration in this study. A fixed bed pyrolysis has been designed and fabricated for obtaining liquid fuel from these date seeds. The major component of the system are fixed bed pyrolysis reactor, liquid condenser and liquid collector. The date seed in particle form is pyrolysed in an externally heated 7.6 cm diameter and 46 cm high fixed bed reactor with nitrogen as the carrier gas. The reactor is heated by means of a biomass source cylindrical heater from 4000C to 6000C. The products are oil, char and gas. The reactor bed temperature, running time and feed particle size are considered as process parameters. The parameters are found to influence the product yield significantly. A maximum liquid yield of 50 wt.% is obtained at a reactor bed temperature of 5000 C for a feed size volume of 0.11- 0.20 cm3 with a running time of 120 minutes. The pyrolysis oil obtained at this optimum process conditions are analyzed for some fuel properties and compared with some other biomass derived pyrolysis oils and also with conventional fuels. The oil is found to possess favorable flash point and reasonable density and viscosity. The higher calorific value is found to be 28.636 MJ/kg which is significantly higher than other biomass derived pyrolysis oils.
Resumo:
A fixed bed pyrolysis has been designed and fabricated for obtaining liquid fuel from Mahogany seeds. The major components of the system are fixed bed pyrolysis reactor, liquid condenser and liquid collectors. The Mahogany seed in particle form is pyrolysed in an externally heated 10 cm diameter and 36 cm high fixed bed reactor with nitrogen as the carrier gas. The reactor is heated by means of a biomass source cylindrical heater from 450oC to 600oC. The products are oil, char and gas. The reactor bed temperature, running time and feed particle size are considered as process parameters. A maximum liquid yield of 54wt% of biomass feed is obtained with particle size of 1.18 mm at a reactor bed temperature of 5500C with a running time of 90 minutes. The oil is found to possess favorable flash point and reasonable density and viscosity. The higher calorific value is found to be 39.9 MJ/kg which is higher than other biomass derived pyrolysis oils.
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Among various thermo-chemical conversion processes, pyrolysis is considered as an emerging technology for liquid oil production. The conversion of biomass waste in the form of plum seed into pyrolysis oil by fixed bed pyrolysis reactor has been taken into consideration in this study. A fixed bed pyrolysis has been designed and fabricated for obtaining liquid fuel from this plum seeds. The major component of the system are fixed bed pyrolysis reactor, liquid condenser and liquid collectors. The plum seed in particle form is pyrolysed in an externally heated 7.6 cm diameter and 46 cm high fixed bed reactor with nitrogen as the carrier gas. The reactor is heated by means of a biomass source cylindrical heater from 4000C to 6000C. The products are oil, char and gas. The reactor bed temperature, running time and feed particle size are considered as process parameters. The parameters are found to influence the product yield significantly. A maximum liquid yield of 39 wt% of biomass feed is obtained with particle size of 2.36-4.75 mm at a reactor bed temperature of 520oC with a running time of 120 minutes. The pyrolysis oil obtained at this optimum process conditions are analyzed for some fuel properties and compared with some other biomass derived pyrolysis oils and conventional fuels. The oil is found to possess favorable flash point and reasonable density and viscosity. The higher calorific value is found to be 22.39 MJ/kg which is higher than other biomass derived pyrolysis oils.
Resumo:
Postburn itch is reported to affect up to 87% of the burn population. Although treatments for postburn itch are multimodal, they remain consistently ineffective. However, recent anecdotal evidence from several outpatients at a tertiary referral hospital suggests that a cream combining beeswax and several herbal oils may be effective in the minimization of postburn itch. The aim of this study was to test the efficacy of beeswax and herbal oil cream against the standard treatment of aqueous cream in the provision of relief from the symptoms of postburn itch. A randomized controlled trial compared two groups using a visual analog scale, frequency of cream application, itch recurrence after cream application, use of antipruritic medications, and sleep disturbance to determine the effect of itch severity and duration. Fifty-two participants were enrolled in the study (84% male) with a mean age of 35 years (SD = 16) and mean burn TBSA of 7.2% (SD = 7.7). Study results found that the beeswax and herbal oil cream reduce itch after application more frequently than aqueous cream (P = .001). In addition, when managed with beeswax and herbal oil cream, participants found that their itch recurred later (P ≤ .001) and their use of antipruritic medications was lower (P = .023). Findings of this study suggest beeswax and herbal oil cream to be more effective in the minimization of postburn itch than aqueous cream. Given this, a larger study examining the efficacy of beeswax and herbal oil cream appears warranted.
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The transient leaf assay in Nicotiana benthamiana is widely used in plant sciences, with one application being the rapid assembly of complex multigene pathways that produce new fatty acid profiles. This rapid and facile assay would be further improved if it were possible to simultaneously overexpress transgenes while accurately silencing endogenes. Here, we report a draft genome resource for N. benthamiana spanning over 75% of the 3.1 Gb haploid genome. This resource revealed a two-member NbFAD2 family, NbFAD2.1 and NbFAD2.2, and quantitative RT-PCR (qRT-PCR) confirmed their expression in leaves. FAD2 activities were silenced using hairpin RNAi as monitored by qRT-PCR and biochemical assays. Silencing of endogenous FAD2 activities was combined with overexpression of transgenes via the use of the alternative viral silencing-suppressor protein, V2, from Tomato yellow leaf curl virus. We show that V2 permits maximal overexpression of transgenes but, crucially, also allows hairpin RNAi to operate unimpeded. To illustrate the efficacy of the V2-based leaf assay system, endogenous lipids were shunted from the desaturation of 18:1 to elongation reactions beginning with 18:1 as substrate. These V2-based leaf assays produced ~50% more elongated fatty acid products than p19-based assays. Analyses of small RNA populations generated from hairpin RNAi against NbFAD2 confirm that the siRNA population is dominated by 21 and 22 nt species derived from the hairpin. Collectively, these new tools expand the range of uses and possibilities for metabolic engineering in transient leaf assays. © 2012 Naim et al.
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Throughout history there have been many different and sometimes bizarre treatments prescribed for burns. Unfortunately many of these treatments still persist today, although they often do not have sufficient evidence to support their use. This paper reviews common first aid and pre-hospital treatments for burns (water--cold or warm, ice, oils, powders and natural plant therapies), possible mechanisms whereby they might work and the literature which supports their use. From the published work to date, the current recommendations for the first aid treatment of burn injuries should be to use cold running tap water (between 2 and 15 degrees C) on the burn, not ice or alternative plant therapies.
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Sugarcane biorefineries co-producing fuels, green chemicals and bio-products offer great potential for improving the profitability and sustainability of sugarcane industries around the world. Sugarcane bagasse is widely regarded as one of the best biomass feedstocks for early adoption and commercialisation of biorefining technologies because of the large scale of the resource and its availability at sugar factories. Biomass biorefineries aim to convert bagasse through biochemical and thermochemical processes to produce low cost fermentable sugars which are a platform for value-adding. Through subsequent fermentation technologies or chemical synthesis, the sugars can be converted to fuels including ethanol and butanol, oils, organic acids such as succinic and levulinic and polymer precursors. Other biorefinery products can include food and animal feeds, plastics, fibre products and resins. Recent advances in biorefinery production technologies are being demonstrated in a unique research facility at the Queensland University of Technology’s Mackay Renewable Biocommodities Pilot Plant in Mackay, Australia. This pilot scale production facility located at Mackay Sugar Ltd’s Racecourse Mill is demonstrating the production of a range of fuels and other products from sugarcane bagasse. This paper will address the opportunities available for sugarcane biorefineries to contribute to future profitability and sustainability of the sugarcane industry.
Resumo:
Thraustochytrids have become of considerable industrial and scientific interest in the past decade due to their health benefits. They have been proven to be the principle source in marine and estuarine fish diets with high percentage of long chain (LC) or polyunsaturated fatty acids (PUFA). Therefore, the oil extracted from fish for human document.forms[0].elements[13].select();consumption is rich in PUFA with high omega-3 fatty acid content. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) of all of the omega-3 fatty acids, are considered beneficial essential oils for humans with a wide range of health benefits. These include brain and neural development in infants, general wellbeing of adults and drug delivery through precursor molecules. They have become one of the most extensively studied organisms for industrial oil preparations as PUFA extraction from fish becomes less profitable. Many forms of these Thraustochytrid oils are being trialled for human consumption all over the world. In Australia, there has been little research performed on these organisms in the past ten years. A few Australian studies have been conducted in the form of comparative studies related to PUFA production within the related genera, but not focussed on their identification or cellular and genomic characterisation. Therefore, the main aim of this study was to investigate the morphological and genetic characteristics of Australian Thraustochytrids in order to aid in their identification and characterisation, as well as to better understand the effect of environmental conditions in the regulation of PUFA production. It was also noted that there was a knowledge gap in the preservation and total genomic DNA extraction of these organisms for the purposes of scientific research. The cryopreservation of these organisms for studies around the world follows existing generic methods. However, it is well understood that many of these generic methods attract not only high costs for chemicals, but also uses considerable storage space and other resources, all of which can be improved with new or modified approaches. In this context, a simple and inexpensive bead preservation method is described, without compromising the storage shelf life. We also describe, for the first time, the effects of culture age on the successful cryopreservation of Thraustochytrids. It was evident in the literature that DNA and RNA extractions for molecular and genetic studies of Thraustochytrids follow the classical phenol-chloroform extraction methods. It was also observed that modern protocols failed to avoid the use of phenol-chloroform rather than improving preparation and cell disruption. In order to provide a high quantity and quality DNA extraction, a modified protocol has been introduced that employs the use of modern commercial extraction kits and standard laboratory equipment. Thraustochytrids have been shown to be highly conserved in their 18S rDNA gene sequences, which is used as the current standard for identification. It was demonstrated that the 18S rDNA gene sequence limits the recognition of closely related genera or within the genera from each member. Therefore, it was proposed that another profile, such as a randomly amplified polymorphic DNA (RAPD) based profiling system, be tested for use in the characterisation of Thraustochytrids. The RAPD profiles were shown to provide a unique DNA fingerprint for each isolate and small variations in their genome were able to be detected. This method involved the use of a minimum number of standard arbitrary primers and with an increase in the number of different primers used, a very high discrimination between organisms could be achieved. However, the method was not suitable for taxonomic purposes because the results did not correlate with other taxonomic features such as morphology. Another knowledge gap was found with respect to Australian Thraustochytrid growth characteristics, in that these had not been recorded and published. In order to rectify this, a record of colony and microscopic features of 12 selected isolates was performed. The results of preliminary studies indicated that further microbiological and biochemical studies are needed for full characterisation of these organisms. This information is of great importance to bio-prospecting of new Thraustochytrids from Australian ecosystems and would allow for their accurate identification, and so permit the prediction of their PUFA capability by comparison with related genera/species. It was well recognized that environmental stress plays a role in the PUFA production and is mainly due to the reactive oxygen species as abiotic stress (Chiou et al., 2001; Okuyama et al., 2008; Shabala et al., 2009; Shabala et al., 2001). In this aspect, this study makes the first attempt towards better understanding of this phenomenon by way of the use of real-time PCR for the detection of environmental effects on the regulation of PUFA production. Three main environmental conditions including temperature, pH and oxygen availability were monitored as stress inducers. In summary, this study provides novel approaches for the preservation and handling of Thraustochytrids, their molecular biological features, taxonomy, characterisation and responses to environmental factors with respect to their oil production enzymes. The information produced from this study will prove to be vital for both industrial and scientific investigations in the future.
Resumo:
SETTING National household survey of adults in South Africa, a middle income country. OBJECTIVE To determine the prevalence and predictors of chronic bronchitis. DESIGN A stratified national probability sample of households was selected. All adults in the selected households were interviewed. Chronic bronchitis was defined as chronic productive cough. Socio-demographic predictors were wealth, education, race, age and urban residence. Personal and exposure variables included history of tuberculosis, domestic exposure to smoky fuels, occupational exposures, smoking and body mass index. RESULTS The overall prevalence of chronic bronchitis was 2.3% in men and 2.8% in women. The strongest predictor of chronic bronchitis was a history of tuberculosis (men, odds ratio [OR] 4.9; 95% confidence interval [CI] 2.6-9.2; women, OR 6.6; 95% CI 3.7-11.9). Other risk factors were smoking, occupational exposure (in men), domestic exposure to smoky fuel (in women) and (in univariate analysis only) being underweight. Wealth and particularly education were protective. CONCLUSION The pattern of chronic bronchitis in South Africa suggests a combination of risk factors that includes not only smoking but also tuberculosis, occupational exposures in men and domestic fuel exposure in women. Control of these risk factors requires public health action across a broad front. The protective role of education requires elucidation.