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Query: UMLS:C0205700 (ash)
 15,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Environmental benefits of underground coal gasification are evaluated. The results showed that through underground coal gasification, gangue discharge is eliminated, sulfur emission is reduced, and the amount of ash, mercury, and tar discharge are decreased. Moreover, effect of underground gasification on underground water is analyzed and CO2 disposal method is put forward.
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PMID:Environmental benefits of underground coal gasification. 1204 1

The lack of landfill capacity, forthcoming EU waste disposal and landfill management legislation and the use of non-renewable and energy intensive natural resources for the end-treatment of old landfills increase pressures to develop new landfill management methods. This paper considers a method for the end-management of old landfills in Finland, which is based on the utilization of forest and paper industry waste flows, wastes from paper recycling (de-inking) and wastes from forest industry energy production. Fibre clay wastes from paper mills, de-inking sludges from de-inking of recovered waste paper and incineration ash from forest industry power plants serve to substitute the use of natural clay for the building of landfill structures for closed landfills. Arguably, this method is preferable to existing practices of natural clay use for landfill building, because it (1) substitutes non-renewable natural clay, (2) consumes less energy and generates less CO2 emissions than the use of natural clay, and (3) eliminates considerable amounts of wastes from paper production, paper consumption and from forest industry energy production. Some difficulties in the application of the method are considered and the waste flow utilization is incorporated into a local forest industry recycling network.
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PMID:Management of old landfills by utilizing forest and energy industry waste flows. 1217 21

Mycorrhizal-induced growth depression of plants in high-P soil has been reported in many species. The carbon costs of factors contributing to this growth depression were analyzed in Volkamer lemon (Citrus volkameriana Tan. & Pasq.) colonized by the mycorrhizal (M) fungus Glomus intraradices Schenck and Smith. M and nonmycorrhizal (NM) plants were each grown at two P-supply rates. Carbon budgets of M and NM plants were determined by measuring whole-plant carbon assimilation and respiration rates using gas-exchange techniques. Biomass, M colonization, tissue-P concentration, and total fatty acid concentration in the fibrous roots were determined. Construction costs of the fibrous roots were estimated from heat of combustion, N, and ash content. Root-growth respiration was derived from daily root growth and root-construction cost. M and NM plants grown in high-P soil were similar in P concentration, daily shoot carbon assimilation, and daily shoot dark respiration. At 52 d after transplanting (DAT), however, combined daily root plus soil respiration was 37% higher for M than for NM plants, resulting in a 20% higher daily specific carbon gain (mmol CO2 [mmol carbon]-1 d-1) in NM than M plants. Estimates of specific carbon gain from specific growth rates indicated about a 10% difference between M and NM plants. Absolute values of specific carbon gain estimated by whole-plant gas exchange and by growth analysis were in general agreement. At 52 DAT, M and NM plants at high P had nearly identical whole-plant growth rates, but M plants had 19% higher root dry weight with 10% higher daily rates of root growth. These allocation differences at high P accounted for about 51% of the differences in root/soil respiration between M and NM plants. Significantly higher fatty acid concentrations in M than NM fibrous roots were correlated with differences in construction costs of the fibrous roots. Of the 37% difference in daily total root/soil respiration observed between high-P M and NM plants at 52 DAT, estimated daily growth respiration accounted for only about 16%, two-thirds of which was associated with construction of lipid-rich roots, and the remaining one-third with greater M root growth rates. Thus, of the 37% more root/soil respiration associated with M colonization of high-P plants, 10% was directly attributable to building lipid-rich roots, 51% to greater M root biomass allocation, and the remaining 39% could have been used for maintenance of the fungal tissue in the root and growth and maintenance of the extramatrical hyphae.
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PMID:Growth Depression in Mycorrhizal Citrus at High-Phosphorus Supply (Analysis of Carbon Costs). 1223 58

The temperature, redox conditions, and residence times of the solid waste on the grate and of the raw gas in the secondary combustion zone determine the mineralization processes of organics in municipal solid waste incinerators. An improved knowledge of the influence of these factors on the incineration process might help to optimize incinerators with regard to mineralization efficiency of organics. This paper presents a method for investigating the influence of process parameters on mineralization of organics to CO2 by using the elemental carbon (EC) and organic carbon (OC) concentrations in the solid residues as indicators. The results obtained by experiments in full-scale incinerators show that the EC concentration in these residues is a good indicator of oxygen supply, whereas the OC/EC ratio is a good indicator of temperature in and above the furnace bed. Very effective burnout of the bottom ash up to 0.95 g of TOC (EC + OC) per kilogram of dry matter (DM) and of the electrostatic precipitator (ESP) ash up to 0.24 g of TOC per kilogram of DM was achieved in a full-scale incinerator.
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PMID:Optimizing municipal solid waste combustion through organic and elemental carbon as indicators. 1266 36

Since the U.S. is the largest emitter of carbon dioxide (CO2), it has become crucial to develop options that are both cost effective and supportive of sustainable development to reduce atmospheric CO2. Electric utility companies have the options of reducing their use of fossil fuels, switching to alternative energy sources, increasing efficiency, or offsetting carbon emissions. This study determined the cost and profitability of sequestering carbon in green ash plantations, and the number of tons of carbon that can be sequestered. The profitability of green ash is 2,342 dollars and 3,645 dollars per acre on site indices (measurement of soil quality) 65 and 105 land, respectively, calculated with a 2.5% alternative rate of return (ARR). These figures shift to -248 dollars and -240 dollars calculated with a 15.0% ARR. If landowners who have an ARR of 2.5% can sell carbon credits for 10 dollars per ton of carbon, profits will increase by 107 dollars per acre on poor sites and 242 dollars on good sites. Over one rotation (cutting cycle), 38.56 net tons of carbon can be sequestered on an acre of poor quality land and 51.35 tons on good quality land. The cost of sequestering carbon, without including revenues from timber production and carbon credits, ranges from a high of 15.20 dollars per ton on poor sites to 14.41 dollars on good sites, calculated with a 2.5% ARR; to a high of 8.51 dollars per ton on poor sites to 7.63 dollars on good sites, calculated with a 15.0% ARR. The cost of storing carbon can be reduced significantly if the trees can be sold for wood products.
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PMID:Economic analysis of sequestering carbon in green ash forests in the Lower Mississippi River Valley. 1294 73

Waste management is in need of a reliable and economical treatment method for metals in fly ashes from municipal solid waste incineration (MSWI). However, no state-of-the-art technique has gained wide acceptance yet. This paper is a synthesis of five elsewhere published investigations covering a project which aimed to assess the possibilities and limitations of adding carbon dioxide (CO2) to fly ash as a stabilization method. Carbonation factors that were studied are the partial pressure of carbon dioxide (CO2), the addition of water, the temperature, and the reaction time. Laboratory experiments were performed applying methods such as factorial experimental design, thermal analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), and leaching assays including pHstat titration and sequential extraction. Leaching data were verified and complemented using chemical equilibrium calculations. Data evaluation was performed by means of multivariate statistics such as multiple linear regression, principal component analysis (PCA), and partial least squares (PLS) modeling. It was found that carbonation is a good prospect for a stabilization technique especially with respect to the major pollutants lead (Pb) and zinc (Zn). Their mobility decreased with increasing factor levels. Dominating factors were the partial pressure of CO2 and the reaction time, while temperature and the addition of water were of minor influence. However, the treatment caused a mobilization of cadmium (Cd), requiring further research on possible countermeasures such as metal demobilization through enhanced silicate formation.
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PMID:Sequestration of metals in carbonated municipal solid waste incineration (MSWI) fly ash. 1295 58

We submerged hatchling western painted turtles Chrysemys picta Schneider, snapping turtles Chelydra serpentina L. and map turtles Graptemys geographica Le Sueur in normoxic and anoxic water at 3 degrees C. Periodically, turtles were removed and whole-body [lactate] and [glycogen] were measured along with relative shell mass, shell water, and shell ash. We analyzed the shell for [Na+], [K+], total calcium, total magnesium, Pi and total CO2. All three species were able to tolerate long-term submergence in normoxic water without accumulating any lactate, indicating sufficient extrapulmonary O2 extraction to remain aerobic even after 150 days. Survival in anoxic water was 15 days in map turtles, 30 days in snapping turtles, and 40 days in painted turtles. Survival of hatchlings was only about one third the life of their adult conspecifics in anoxic water. Much of the decrease in survival was attributable to a dramatically lower shell-bone content (44% ash in adult painted turtles vs. 3% ash in hatchlings of all three species) and a smaller buffer content of bone (1.3 mmol g(-1) CO2 in adult painted turtles vs. 0.13-0.23 mmol g(-1) CO2 in hatchlings of the three species). The reduced survivability of turtle hatchlings in anoxic water requires that hatchlings either avoid aquatic hibernacula that may become severely hypoxic or anoxic (snapping turtles), or overwinter terrestrially (painted turtles and map turtles).
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PMID:Lactate accumulation, glycogen depletion, and shell composition of hatchling turtles during simulated aquatic hibernation. 1523 17

Fraxinus uhdei (Wenz.) Lingelsh (tropical ash), a species introduced to Hawaii from Mexico, invades forests of the endemic tree Acacia koa A.Gray (koa). We examined physiological and morphological characteristics of koa and tropical ash to explore possible mechanisms that may facilitate invasion of koa forests by tropical ash. Seedlings of both species were grown in a greenhouse in three light treatments: 100% photosynthetic photon flux (PPF); 18% PPF; and 2% PPF inside the greenhouse. Light compensation point, maximum CO2 assimilation rate and dark respiration rate of seedlings differed significantly among light treatments, but were similar between species. A defoliation experiment indicated that tropical ash was better able to survive defoliation than koa, especially under high-light conditions. Tropical ash seedlings allocated more carbon (C) and nitrogen (N) to storage per unit PPF than koa seedlings. Total nonstructural carbohydrates were positively correlated with plant survival in both species. The patterns of C and N allocation associated with tropical ash seedlings favor their survival in high light, under intense herbivory and on sites where N availability is seasonal or highly variable. Variation in carbohydrate storage between koa and tropical ash greatly exceeded variation in photosynthetic performance at the leaf level.
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PMID:Photosynthesis, carbohydrate storage and survival of a native and an introduced tree species in relation to light and defoliation. 1529 55

A study was conducted to evaluate effects of different bone preparation methods on bone parameters and the correlations between bone breaking strength and the other bone parameters. Bone breaking strength is dramatically changed depending on bone preparation methods, whereas other bone parameters such as ash content and ash concentration are not significantly influenced by bone preparation methods. Thus, the objective of this study was to evaluate the effects of 3 bone preparations (fresh, dry, and fat-free dry) on bone parameters and the relationship between bone breaking strength and bone parameters. Sixty Single Comb White Leghorn hens were used for this study. Hens were euthanized by CO2 gas, and the right tibia and femur were collected. The bones were divided into 3 treatment groups: fresh, dry, and fat-free dry. There were no significant differences in fresh weight, bone volume, dried weight, ash weight, and ash concentration of tibia and femur among the treatments. However, fresh tibia (24.13 kg) exhibited more bone breaking strength compared with the dried (9.90 kg) and fat-free dried bones (7.41 kg) (P < 0.05). The bone breaking strength (20.97 kg) of fresh femur was also significantly higher than the dried (9.22 kg) and fat-free dried femurs (6.94 kg). The bone breaking strength of the fresh bone was highly correlated with dried weight, ash weight, and ash concentration, whereas that of the fat-free dried bone was poorly correlated with the other bone parameters. The results indicate that fresh bone gives better bone breaking strength correlated to the other bone parameters than dry or fat-free dry preparation.
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PMID:Research note: Effects of different bone preparation methods (fresh, dry, and fat-free dry) on bone parameters and the correlations between bone breaking strength and the other bone parameters. 1551 May 50

The 0.1-2 mm fraction of a MSWI-bottom ash cannot be used as granular construction material because leaching of Cu exceeds Flemish limit values. In addition, leaching of Ba, Mo and Sb exceeds informal limit values. Leaching characteristics thus need to be improved. Carbonation was the chosen treatment method and this was performed by placing samples in a CO2 chamber. The CO2 percentage and the temperature of the chamber atmosphere, as well as the initial humidity of the samples, were varied to optimize carbonation parameters. Metal leaching was tested with the EN 12457 extraction test. Carbonation decreased Cu leaching from 3.3 to 1.0 mg/kg, but not yet to below the official limit value of 0.5 mg/kg. Leaching of Mo and Sb remained fairly constant or even increased after carbonation, but their limit values are only informal. Ba leaching decreased to below the informal limit value. Carbonation also caused Cr leaching to increase, in some cases to above the official limit value. Of the tested parameters, a CO2 percentage of 10% and a carbonation temperature of 50 degrees C in the atmosphere, together with ash humidity between 13% and 25% appeared to give the best leaching results. The main carbonation reactions took place within the first 24 h.
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PMID:Carbonation of MSWI-bottom ash to decrease heavy metal leaching, in view of recycling. 1582 44


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