Characterization of early-age hydration processes in lime-ceramic binders using isothermal calorimetry, X-ray diffraction and scanning electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Jerman, Miloš; Tydlitát, Vratislav; Keppert, Martin; Čáchová, Monika; Černý, Robert, E-mail: cernyr@fsv.cvut.cz

2016-06-10

Highlights: • Early age hydration processes in lime-ceramic binders are analyzed within a wide range of component ratios. • The applied waste ceramic dust exhibits partial hydraulic properties, ettringite and calcite are formed. • Transition from tobermorite- to jennite-like structures is identified by SEM within the first 48 h. • The highest specific hydration heat after 300 h, 63 J/g, is measured for the binder containing 70% ceramic. • Substantial effect of the heat of wetting is observed, ranging from 10 J/g for lime to 3.9 J/g for ceramic. - Abstract: Early-age hydration processes in a lime-ceramic-water system are analyzed within the whole range of possible lime/ceramic ratios. The isothermal calorimetry shows a substantial effect of the heat of wetting on the total heat evolved, ranging from 10 J/g for lime to 3.9 J/g for ceramic. The highest specific hydration heat of 63 J/g during the analyzed 300-h hydration period exhibits the blended binder containing 70% ceramic and 30% lime which correlates well with the highest compressive and bending strengths of the paste prepared using this blend. Portlandite, ettringite and calcite are the main phases identified by the X-ray diffraction analysis after the hydration of ceramic-rich blends. According to the results of scanning electron microscopy, the initial course of pozzolanic reaction is for this type of binders characterized by the transition from tobermorite-like calcium-silicate-hydrate structures into jennite-like structures within the first 48 h. Blends with the ceramic content lower than 70% show a high portion of portlandite, calcite is present in low amount, and the jennite-like structures are observed after 48 h, following the initial formation of components with a very high Ca content. The favorable properties of the ceramic-rich blended binders can be explained by the partial hydraulic character of the ceramic. With the specific hydration heat of 29 J/g after 300 h and compressive strength

Characterization of early-age hydration processes in lime-ceramic binders using isothermal calorimetry, X-ray diffraction and scanning electron microscopy

International Nuclear Information System (INIS)

Jerman, Miloš; Tydlitát, Vratislav; Keppert, Martin; Čáchová, Monika; Černý, Robert

2016-01-01

Highlights: • Early age hydration processes in lime-ceramic binders are analyzed within a wide range of component ratios. • The applied waste ceramic dust exhibits partial hydraulic properties, ettringite and calcite are formed. • Transition from tobermorite- to jennite-like structures is identified by SEM within the first 48 h. • The highest specific hydration heat after 300 h, 63 J/g, is measured for the binder containing 70% ceramic. • Substantial effect of the heat of wetting is observed, ranging from 10 J/g for lime to 3.9 J/g for ceramic. - Abstract: Early-age hydration processes in a lime-ceramic-water system are analyzed within the whole range of possible lime/ceramic ratios. The isothermal calorimetry shows a substantial effect of the heat of wetting on the total heat evolved, ranging from 10 J/g for lime to 3.9 J/g for ceramic. The highest specific hydration heat of 63 J/g during the analyzed 300-h hydration period exhibits the blended binder containing 70% ceramic and 30% lime which correlates well with the highest compressive and bending strengths of the paste prepared using this blend. Portlandite, ettringite and calcite are the main phases identified by the X-ray diffraction analysis after the hydration of ceramic-rich blends. According to the results of scanning electron microscopy, the initial course of pozzolanic reaction is for this type of binders characterized by the transition from tobermorite-like calcium-silicate-hydrate structures into jennite-like structures within the first 48 h. Blends with the ceramic content lower than 70% show a high portion of portlandite, calcite is present in low amount, and the jennite-like structures are observed after 48 h, following the initial formation of components with a very high Ca content. The favorable properties of the ceramic-rich blended binders can be explained by the partial hydraulic character of the ceramic. With the specific hydration heat of 29 J/g after 300 h and compressive strength

Influence of Hydrated Lime on the Properties and Permanent Deformation of the Asphalt Concrete Layers in Pavement

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Al-Tameemi Ahmed F.

2015-07-01

Full Text Available Flexible or asphalt concrete pavement is the paving system most widely adopted all over the world. It has been recognized that there are many different types of the factors affecting the performance and durability of asphalt concrete pavement, including the service conditions, such as: the variation of temperature from mild to extremes and the repeated excessive axle loading as well as the inadequate quality of the raw materials. All of these when combined together are going to accelerate the occurrence of distresses in flexible pavement such as permanent deformation and fatigue cracking. As the result, there has an urgent need to enhance the ability of asphalt concrete mixture to resist distresses happened in pavement. Use of additives is one of the techniques adopted to improve pavement properties. It has been found that hydrated lime might be one of the effective additives because it is widely available and relatively cheap compared to other modifiers like polymers. This paper presents an experimental study of the hydrated-lime modified asphalt concrete mixtures. Five different percentages of the hydrated lime additive were investigated, namely (1, 1.5, 2, 2.5 and 3 percent. The hydrated lime additive was used as partial replacement of limestone filler by total weight of the aggregate. The designed Hot Mix Asphalt (HMA concretes are for the application of three pavement courses, i.e. Surface, Leveling and Base. These mixtures are designed and tested following Marshall procedure and uniaxial repeated loading to evaluate permanent deformation at different temperatures of 20°C, 40°C and 60°C. The experimental results show that the addition of hydrated lime as a partial replacement of ordinary limestone mineral filler results a significant improvement on mechanical properties and the resistant to permanent deformation of the designed asphalt concrete mixtures.

Location of quarries of magnesian lime used as raw material of Roman plasters in western Lombardy (Italy

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Roberto Bugini

2017-01-01

Full Text Available Lime as building material was widely diffused in Roman architecture of western Lombardy. The presence of magnesite (magnesium carbonate was detected in painted plasters coming from roman sites of Milano: magnesite indicates the use of dolomite to make the lime. Dolomite rocks widely outcrop in the Lombard Prealps: light grey dolomites and dolomitic limestones (Dolomia del Salvatore, Ladinian-Anisian; grey dolomites, sometimes with cyclothemes (Dolomia Principale, Norian. There is no evidence of Roman lime quarries or kilns in this area; the Romans probably exploited the same dolomite outcrops, located along the eastern shore of lake Maggiore, where lime was produced from the Middle Ages onwards. The glacio-fluvial deposits of the middle course of the river Adda (cobbles, pebbles of siliceous limestone together with limestone and dolomite outcropping in the river basin were another medieval and modern source of raw material, mainly to make a moderately hydraulic lime (called “calce forte”, but this kind of lime is lacking in Roman plasters.

Managing Salmonella Typhimurium and Escherichia coli O157:H7 in soil with hydrated lime - An outdoor study in lysimeters and field plots.

Science.gov (United States)

Nyberg, Karin A; Vinnerås, Björn; Albihn, Ann

2014-01-01

An outbreak of Salmonella Typhimurium or E. coli O157:H7 among domestic animals can have great financial consequences for an animal enterprise but also be a threat for public health as there is a risk for transmission of the infection through the environment. In order to minimize disease transmission, it is important to treat not only the affected animals but also the areas on which they have been kept. In the present study, the effect of hydrated lime as a treatment for Salmonella Typhimurium or E. coli O157:H7 contaminated soil was investigated. The study was performed outdoors, in a lysimeter system and in field plots. The soils were spiked with Salmonella Typhimurium and/or E. coli O157:H7 and hydrated lime was added at three different concentrations (0.5, 1 and 2%). Sampling was performed over one month, and the levels of bacteria were analyzed by standard culture methods. In addition, the soil pH was monitored throughout the study. The results showed that application of 0.5-1 kg hydrated lime per m(2) reduced both Salmonella Typhimurium and E. coli O157:H7 numbers to below the detection limit (2 log10 CFU g-1 soil) in 3-7 days. Lower application rates of hydrated lime did not reduce pathogen numbers in the lysimeter study, but in the field plots no E. coli O157:H7 was detected at the end of the four-week study period regardless of hydrated lime application. A recommended strategy for treating a Salmonella Typhimurium or E. coli O157:H7 contaminated soil could therefore be to monitor the pH over the time of treatment and to repeat hydrated lime application if a decrease in pH is observed.

Underlying mechanisms and effects of hydrated lime and selenium application on cadmium uptake by rice (Oryza sativa L.) seedlings.

Science.gov (United States)

Huang, Gaoxiang; Ding, Changfeng; Guo, Fuyu; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

2017-08-01

A pot experiment was conducted to investigate the effects of selenium (Se) and hydrated lime (Lime), applied alone or simultaneously (Se+Lime), on growth and cadmium (Cd) uptake and translocation in rice seedlings grown in an acid soil with three levels of Cd (slight, mild, and moderate contamination). In the soil with 0.41 mg kg -1 Cd (slight Cd contamination), Se addition alone significantly decreased Cd accumulation in the root and shoot by 35.3 and 40.1%, respectively, but this tendency weakened when Cd level in the soil increased. However, Se+Lime treatment effectively reduced Cd accumulation in rice seedlings in the soil with higher Cd levels. The results also showed that Se application alone strongly increased Cd concentration in the iron plaque under slight Cd contamination, which was suggested as the main reason underlying the inhibition of Cd accumulation in rice seedlings. Se+Lime treatment also increased the ability of the iron plaques to restrict Cd uptake by rice seedlings across all Cd levels and dramatically decreased the available Cd concentration in the soil. These results suggest that Se application alone would be useful in the soil with low levels of Cd, and the effect would be enhanced when Se application is combined with hydrated lime at higher Cd levels.

Effects of hydrated lime and quicklime on the decay of buried human remains using pig cadavers as human body analogues.

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Schotsmans, Eline M J; Denton, John; Dekeirsschieter, Jessica; Ivaneanu, Tatiana; Leentjes, Sarah; Janaway, Rob C; Wilson, Andrew S

2012-04-10

Recent casework in Belgium involving the search for human remains buried with lime, demonstrated the need for more detailed understanding of the effect of different types of lime on cadaver decomposition and its micro-environment. Six pigs (Sus scrofa) were used as body analogues in field experiments. They were buried without lime, with hydrated lime (Ca(OH)(2)) and with quicklime (CaO) in shallow graves in sandy loam soil in Belgium and recovered after 6 months of burial. Observations from these field recoveries informed additional laboratory experiments that were undertaken at the University of Bradford, UK. The combined results of these studies demonstrate that despite conflicting evidence in the literature, hydrated lime and quicklime both delay the decay of the carcass during the first 6 months. This study has implications for the investigation of clandestine burials and for a better understanding of archaeological plaster burials. Knowledge of the effects of lime on decomposition processes also has bearing on practices involving burial of animal carcasses and potentially the management of mass graves and mass disasters by humanitarian organisations and DVI teams. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Application of sphagnum peat, calcium carbonate and hydrated lime for immobilizing radioactive and hazardous contaminants in the subsurface

International Nuclear Information System (INIS)

Longmire, P.A.; Thomson, B.M.; Eller, P.G.; Barr, M.E.

1991-01-01

Batch experiments, mineralogical studies, and geochemical modeling were conducted to evaluate the effectiveness of sphagnum peat, calcium carbonate, and hydrated lime in removing dissolved concentrations of As, Mo, NO 3 , and U present in uranium-tailings pore water at Gunnison, Colorado. Amounts of As, Mo, and U removal by sphagnum peat, calcium carbonate, and hydrated lime at 5.0,2.5, and 2.5 wt.%, respectively, were typically above 97%. Nitrate removal ranged between 55 and 80%. Significant contaminant removal was achieved by sphagnum peat alone at pH 3.18. Results from base potentiometric titration and IR spectroscopy investigations suggest that U(VI) binds onto carboxylate and phenolate groups. Addition of 2.5 wt.% hydrated lime to the acidic tailings increased Mo concentrations by a factor of 2 under moderately alkaline conditions (pH 12). During neutralization of tailings-pore water, precipitation of ferric oxyhydroxides may provide additional removal of As, Mo, and U(VI) from solution through adsorption and coprecipitation processes. Sphagnum peat and other forms of solid organic matter effectively remove anthropogenic organic compounds from solution through hydrophobic sorption and partitioning processes

Influence of aggregate and supplementary cementitious materials on the properties of hydrated lime (CL90s mortars

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S. Pavía

2016-11-01

Full Text Available Hydrated lime is a historic material currently used in conservation. It hardens slowly by carbonation slowing construction however, supplementary cementitious materials accelerate hardening enhancing strength. Hydrated-lime mortars with rice husk ash–RHA-; ground granulated blastfurnace slag–GGBS- and increasing amounts of two aggregates were studied. Increasing aggregate lowered strength as interfacial zones proliferate; it lowered hygric properties and raised water demand. Aggregate content/composition didn’t affect the high water retention. For the higher aggregate contents (90 days, limestone mortars are c.20% stronger than silica mortars while the (1:1 silica sand mortars are 56% stronger in flexion. Additions increased strength with little impact on hygric properties. GGBS increased strength c.six times. RHA increased strength with little impact on hygric properties due to its great specific surface and high water-demand increasing porosity. GGBS and RHA properties ruling hydrate production and the kinetics of the pozzolanic reaction are considered partially responsible for the mortar property variation.

Advanced treatment of swine wastewater using an agent synthesized from amorphous silica and hydrated lime.

Science.gov (United States)

Tanaka, Yasuo; Hasegawa, Teruaki; Sugimoto, Kiyomi; Miura, Keiichi; Aketo, Tsuyoshi; Minowa, Nobutaka; Toda, Masaya; Kinoshita, Katsumi; Yamashita, Takahiro; Ogino, Akifumi

2014-01-01

Advanced treatment using an agent synthesized from amorphous silica and hydrated lime (M-CSH-lime) was developed and applied to swine wastewater treatment. Biologically treated wastewater and M-CSH-lime (approximately 6 w/v% slurry) were fed continuously into a column-shaped reactor from its bottom. Accumulated M-CSH-lime gradually formed a bed layer. The influent permeated this layer and contacted the M-CSH-lime, and the treatment reaction progressed. Treated liquid overflowing from the top of the reactor was neutralized with CO₂gas bubbling. The colour removal rate approximately exceeded 50% with M-CSH-lime addition rates of > 0.15 w/v%. The removal rate of PO(3⁻)(4) exceeded 80% with the addition of>0.03 w/v% of M-CSH-lime. The removal rates of coliform bacteria and Escherichia coli exceeded 99.9% with > 0.1 w/v%. Accumulated M-CSH-lime in the reactor was periodically withdrawn from the upper part of the bed layer. The content of citric-acid-soluble P₂O₅ in the recovered matter was>15% when the weight ratio of influent PO(3⁻)(4) -P to added M-CSH-lime was > 0.15. This content was comparable with commercial phosphorus fertilizer. The inhibitory effect of recovered M-CSH-lime on germination and growth of leafy vegetable komatsuna (Brassica rapa var. perviridis) was evaluated by an experiment using the Neubauer's pot. The recovered M-CSH-lime had no negative effect on germination and growth. These results suggest that advanced water treatment with M-CSH-lime was effective for simultaneous removal of colour, [Formula: see text] and coliform bacteria at an addition rate of 0.03-0.15 w/v%, and that the recovered M-CSH-lime would be suitable as phosphorus fertilizer.

Short-term effects of hydrated lime and quicklime on the decay of human remains using pig cadavers as human body analogues: Laboratory experiments.

Science.gov (United States)

Schotsmans, Eline M J; Denton, John; Fletcher, Jonathan N; Janaway, Robert C; Wilson, Andrew S

2014-05-01

Contradictions and misconceptions regarding the effect of lime on the decay of human remains have demonstrated the need for more research into the effect of different types of lime on cadaver decomposition. This study follows previous research by the authors who have investigated the effect of lime on the decomposition of human remains in burial environments. A further three pig carcasses (Sus scrofa), used as human body analogues, were observed and monitored for 78 days without lime, with hydrated lime (Ca(OH)2) and with quicklime (CaO) in the taphonomy laboratory at the University of Bradford. The results showed that in the early stages of decay, the unlimed and hydrated lime cadavers follow a similar pattern of changes. In contrast, the application of quicklime instigated an initial acceleration of decay. Microbial investigation demonstrated that the presence of lime does not eliminate all aerobic bacteria. The experiment also suggested that lime functions as a sink, buffering the carbon dioxide evolution. This study complements the field observations. It has implications for the investigation of time since death of limed remains. Knowledge of the effects of lime on decomposition processes is of interest to forensic pathologists, archaeologists, humanitarian organisations and those concerned with disposal of animal carcasses or human remains in mass disasters. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The effects of silica fume and hydrated lime on the strength development and durability characteristics of concrete under hot water curing condition

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Hamza Ali

2017-01-01

Full Text Available Sustainability is considered to be highly important for preserving continued industrial growth and human development. Concrete, being the world’s largest manufacturing material comprises cement as an essential binding component for strength development. However, excessive production of cement due to high degree of construction practices around the world frames cement as a leading pollutant of releasing significant amounts of CO2 in the atmosphere. To overcome this environmental degradation, silica fume and hydrated lime are used as partial replacements to cement. This paper begins with the examination of the partial replacement levels of hydrated lime and silica fume in concrete and their influence on the mechanical properties and durability characteristics of concrete. The effect of hot water curing on concrete incorporated with both silica fume and hydrated lime is also investigated in this paper. The results reported in this paper show that the use of silica fume as a partial replacement material improved both the mechanical properties and durability characteristics of concrete due to the formation of calcium silica hydrate crystals through the pozzolanic reaction. Although the hydrated lime did not significantly contribute in the development of strength, its presence enhanced the durability of concrete especially at long-term. The results also showed that hot water curing enhanced the strength development of concrete incorporated with silica fume due to the accelerated rate of both the hydration and pozzolanic reaction that takes place between silica fume and calcium hydroxide of the cement matrix particularly at early times. The results reported in this paper have significant contribution in the development of sustainable concrete. The paper does not only address the use of alternative binders as a partial replacement material in concrete but also suggest proper curing conditions for the proposed replacement materials. These practices

Effect of some soil amendments on soil properties and plant growth in Southern Thailand acid upland soil

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Onthong, C.

2007-01-01

Full Text Available One of the major factors limiting plant growth is acid soil. In general lime is used for soil amendment in acid soil. However, It has been reported that gypsum or phosphogypsum can be used for ameliorating soilacidity. Pot experiment was conducted to study the effects of lime, phosphogypsum and kieserite on soil properties and plant growth in Kho Hong soil series (coarse loamy, kaolinitic,isohyperthermic, TypicKandiudults which was considered as acid upland soil (pH 5.07. Sweet corn variety INSEE 2 was used as the test crop. The experiment was a completely randomized design with 4 replications and 19 treatments asfollow : unamended, application of hydrated lime and dolomite to raise soil pH at 5.5, application of hydrated lime and dolomite combined with phosphogypsum at the rate that can supply calcium 0.25, 0.50,0.75 and 1 time of both limes, application of hydrated lime and dolomite combined with kieserite at the rate 0.25, 0.50,0.75 and 1 times of sulfur requirement for corn (40 kg S ha-1. The result showed that shoot and root dry weights of corn were increased when lime materials, phosphogypsum and kieserite were applied and the drymatter weights were increased according to the increasing of phosphogypsum and kieserite. The maximum shoot dry weight (18.98 g pot-1 was obtained when 1 times of kieserite was supplied with dolomite and wassignificantly (P<0.01 higher than those of the unamended treatment, only hydrated lime and dolomite treatments, which had dry weights of 12.64, 15.18 and 15.67 g pot-1 respectively. Phosphorus and K uptakewere not significantly different in all treatments and the lowest uptake of N, Ca, Mg and S was obtained in the unamended treatment. The maximum uptake of N (512.10 mg pot-1 was found when 0.5 times ofphosphogypsum was applied together with dolomite. Calcium and Mg uptake was likely to increase according to the increasing rate of soil amendment application. Highest uptake of Ca (42.51 mg pot-1 was obtainedwhen

Full quantitative phase analysis of hydrated lime using the Rietveld method

Energy Technology Data Exchange (ETDEWEB)

Lassinantti Gualtieri, Magdalena, E-mail: magdalena.gualtieri@unimore.it [Dipartimento Ingegneria dei Materiali e dell' Ambiente, Universita Degli Studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41100 Modena (Italy); Romagnoli, Marcello; Miselli, Paola; Cannio, Maria [Dipartimento Ingegneria dei Materiali e dell' Ambiente, Universita Degli Studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41100 Modena (Italy); Gualtieri, Alessandro F. [Dipartimento di Scienze della Terra, Universita Degli Studi di Modena e Reggio Emilia, I-41100 Modena (Italy)

2012-09-15

Full quantitative phase analysis (FQPA) using X-ray powder diffraction and Rietveld refinements is a well-established method for the characterization of various hydraulic binders such as Portland cement and hydraulic limes. In this paper, the Rietveld method is applied to hydrated lime, a non-hydraulic traditional binder. The potential presence of an amorphous phase in this material is generally ignored. Both synchrotron radiation and a conventional X-ray source were used for data collection. The applicability of the developed control file for the Rietveld refinements was investigated using samples spiked with glass. The results were cross-checked by other independent methods such as thermal and chemical analyses. The sample microstructure was observed by transmission electron microscopy. It was found that the consistency between the different methods was satisfactory, supporting the validity of FQPA for this material. For the samples studied in this work, the amount of amorphous material was in the range 2-15 wt.%.

Full quantitative phase analysis of hydrated lime using the Rietveld method

International Nuclear Information System (INIS)

Lassinantti Gualtieri, Magdalena; Romagnoli, Marcello; Miselli, Paola; Cannio, Maria; Gualtieri, Alessandro F.

2012-01-01

Full quantitative phase analysis (FQPA) using X-ray powder diffraction and Rietveld refinements is a well-established method for the characterization of various hydraulic binders such as Portland cement and hydraulic limes. In this paper, the Rietveld method is applied to hydrated lime, a non-hydraulic traditional binder. The potential presence of an amorphous phase in this material is generally ignored. Both synchrotron radiation and a conventional X-ray source were used for data collection. The applicability of the developed control file for the Rietveld refinements was investigated using samples spiked with glass. The results were cross-checked by other independent methods such as thermal and chemical analyses. The sample microstructure was observed by transmission electron microscopy. It was found that the consistency between the different methods was satisfactory, supporting the validity of FQPA for this material. For the samples studied in this work, the amount of amorphous material was in the range 2–15 wt.%.

Long-term effects of hydrated lime and quicklime on the decay of human remains using pig cadavers as human body analogues: Field experiments.

Science.gov (United States)

Schotsmans, Eline M J; Fletcher, Jonathan N; Denton, John; Janaway, Robert C; Wilson, Andrew S

2014-05-01

An increased number of police enquiries involving human remains buried with lime have demonstrated the need for more research into the effect of different types of lime on cadaver decomposition and its micro-environment. This study follows previous studies by the authors who have investigated the effects of lime on the decay of human remains in laboratory conditions and 6 months of field experiments. Six pig carcasses (Sus scrofa), used as human body analogues, were buried without lime with hydrated lime (Ca(OH)2) and quicklime (CaO) in shallow graves in sandy-loam soil in Belgium and recovered after 17 and 42 months of burial. Analysis of the soil, lime and carcasses included entomology, pH, moisture content, microbial activity, histology and lime carbonation. The results of this study demonstrate that despite conflicting evidence in the literature, the extent of decomposition is slowed down by burial with both hydrated lime and quicklime. The more advanced the decay process, the more similar the degree of liquefaction between the limed and unlimed remains. The end result for each mode of burial will ultimately result in skeletonisation. This study has implications for the investigation of clandestine burials, for a better understanding of archaeological plaster burials and potentially for the interpretation of mass graves and management of mass disasters by humanitarian organisation and DVI teams. Copyright © 2014. Published by Elsevier Ireland Ltd.

Kinetics of the reaction of hydrated lime with SO{sub 2} at low temperatures: effects of the presence of CO{sub 2}, O{sub 2}, and NOx

Energy Technology Data Exchange (ETDEWEB)

Liu, C.F.; Shih, S.M. [National Taiwan University, Taipei (Taiwan). Dept. of Chemical Engineering

2008-12-15

The effects of the presence Of CO{sub 2}, O{sub 2}, and NOx in the flue gas on the kinetics of the sulfation of hydrated lime at low temperatures were studied using a differential fixed-bed reactor. When O{sub 2} and NOx were not present together the reaction kinetics was about the same as that under gas mixtures containing SO{sub 2}, H{sub 2}O, and N2 only. When both O{sub 2} and NOx were present, sulfation of hydrated lime was greatly enhanced, forming a large amount of calcium sulfate in addition to calcium sulfite. Sulfation of hydrated lime was well described by the surface coverage model, despite the gas-phase conditions being different. Relative humidity is the major factor affecting the reaction, and its effect was more marked when both O{sub 2} and NOx were present. The kinetic model equations obtained in this work can be used to describe the sulfation of hydrated lime in the low-temperature dry and semidry flue gas desulfurization processes with or without an upstream NOx removal unit.

Comparative evaluation of aerial lime mortars for architectural conservation

OpenAIRE

Faria, Paulina; Henriques, Fernando M.A.; Rato, Vasco

2008-01-01

Journal of Cultural Heritage 9 (2008) 338-346 International bibliography on conservation usually refers that mortars made with lime putty with long extinction periods behave better than others made with the current dry hydrated limes. In order to evaluate this assess, an experimental study of lime mortars was carried out, using dry hydrated lime and two lime putties. It becomes clear that the use of lime putties with long extinction periods in mortars allow better performances, pa...

Potential Use Of Carbide Lime Waste As An Alternative Material To Conventional Hydrated Lime Of Cement-Lime Mortars

OpenAIRE

Al Khaja, Waheeb A.

1992-01-01

The present study aimed at the possibility of using the carbide lime waste as an alternative material to the conventional lime used for cement-lime mortar. The waste is a by-product obtained in the generation of acetylene from calcium carbide. Physical and chemical properties of the wastes were studied. Two cement-lime-sand mix proportions containing carbide lime waste were compared with the same mix proportions containing conventional lime along with a control mix without lime. Specimens wer...

Simultaneous removal of colour, phosphorus and disinfection from treated wastewater using an agent synthesized from amorphous silica and hydrated lime.

Science.gov (United States)

Yamashita, Takahiro; Aketo, Tsuyoshi; Minowa, Nobutaka; Sugimoto, Kiyomi; Yokoyama, Hiroshi; Ogino, Akifumi; Tanaka, Yasuo

2013-01-01

An agent synthesized from amorphous silica and hydrated lime (CSH-lime) was investigated for its ability to simultaneously remove the colour, phosphorus and disinfection from the effluents from wastewater treatment plants on swine farms. CSH-lime removed the colour and phosphate from the effluents, with the colour-removal effects especially high at pH 12, and phosphorous removal was more effective in strongly alkaline conditions (pH > 10). Colour decreased from 432 +/-111 (mean +/- SD) to 107 +/- 41 colour units and PO4(3-)P was reduced from 45 +/- 39 mg/L to undetectable levels at the CSH-lime dose of 2.0% w/v. Moreover, CSH-lime reduced the total organic carbon from 99.0 to 37.9 mg/L at the dose of 2.0% w/v and was effective at inactivating total heterotrophic and coliform bacteria. However, CSH-lime did not remove nitrogen compounds such as nitrite, nitrate and ammonium. Colour was also removed from dye solutions by CSH-lime, at the same dose.

Effects of dicyandiamide and dolomite application on N2O emission from an acidic soil.

Science.gov (United States)

Shaaban, Muhammad; Wu, Yupeng; Peng, Qi-an; Lin, Shan; Mo, Yongliang; Wu, Lei; Hu, Ronggui; Zhou, Wei

2016-04-01

Soil acidification is a major problem for sustainable agriculture since it limits productivity of several crops. Liming is usually adopted to ameliorate soil acidity that can trigger soil processes such as nitrification, denitrification, and loss of nitrogen (N) as nitrous oxide (N2O) emissions. The loss of N following liming of acidic soils can be controlled by nitrification inhibitors (such as dicyandiamide). However, effects of nitrification inhibitors following liming of acidic soils are not well understood so far. Here, we conducted a laboratory study using an acidic soil to examine the effects of dolomite and dicyandiamide (DCD) application on N2O emissions. Three levels of DCD (0, 10, and 20 mg kg(-1); DCD0, DCD10, and DCD20, respectively) were applied to the acidic soil under two levels of dolomite (0 and 1 g kg(-1)) which were further treated with two levels of N fertilizer (0 and 200 mg N kg(-1)). Results showed that N2O emissions were highest at low soil pH levels in fertilizer-treated soil without application of DCD and dolomite. Application of DCD and dolomite significantly (P ≤ 0.001) reduced N2O emissions through decreasing rates of NH4 (+)-N oxidation and increasing soil pH, respectively. Total N2O emissions were reduced by 44 and 13% in DCD20 and dolomite alone treatments, respectively, while DCD20 + dolomite reduced N2O emissions by 54% when compared with DCD0 treatment. The present study suggests that application of DCD and dolomite to acidic soils can mitigate N2O emissions.

Influence of supplementary cementitious materials on water transport kinetics and mechanical properties of hydrated lime and cement mortars

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Ince, C.

2015-06-01

Full Text Available The purpose of this paper is an investigation of the possible role of supplementary cementitious materials (SCMs on water transport kinetics and mechanical properties of hydrated lime (CL90 and Portland cement (PC mortars. The properties of hydrated lime are significantly different from those of cement and therefore modifying fresh and hardened properties of these mortars are vital for mortar/substrate optimisation in masonry construction. The parameters investigated in this paper often are the main barriers to the use of hydrated lime in construction practice. The results show that transfer sorptivity and time to dewater freshly-mixed hydrated lime mortars can be modified when binder is partially replaced with SCMs. Compressive strength of CL90 mortars is increased systematically with the increased replacement levels of SCMs and the results are supported with the microstructural images. The ability to modify the water transport kinetics and mechanical properties allows compatibility between the mortar and the substrate unit in masonry construction.El objetivo de este artículo es investigar el papel de los materiales cementantes suplementarios (SCMs en la cinética de transporte del agua y en las propiedades mecánicas de los morteros de cal hidratada (CL90 y cemento Portland. Las propiedades de la cal hidratada son significativamente diferentes a las del cemento y por lo tanto el control de las propiedades de los morteros frescos y endurecidos es fundamental en la optimización mortero/substrato en albañilería. Los parámetros estudiados en este trabajo son a menudo las principales barreras para el uso de la cal hidratada en la práctica de la construcción. Los resultados indican que la absortividad y el tiempo necesario para deshidratar morteros de cal hidratada recién mezclados pueden ser controlados cuando el conglomerante es parcialmente remplazado por SCMs. La resistencia a compresión de los morteros CL90 aumenta sistem

Simulation of self-healing of dolomitic lime mortar

NARCIS (Netherlands)

Lubelli, B.; Nijland, T.G.; Van Hees, R.P.J.

2011-01-01

In the present research a test procedure was set up to reproduce self-healing on lime-based (both pure calcium and magnesium-calcium) mortar specimens in laboratory. After few months testing, during which the specimens were subjected to wet-dry cycles, thin sections of the specimens were prepared

Hygroscopic slaking of lime with steam or humid air. New energy effective lime slaking technology in kraft pulping; Hygroskopisk slaeckning av kalk med aanga eller fuktig luft. Ny energieffektiv teknik foer slaeckning av mesakalk i sulfatmassaindustrin

Energy Technology Data Exchange (ETDEWEB)

Lundqvist, Roland

2005-12-15

Lime stone is widely used in chemical recovery for regeneration of white liquor in kraft pulping. Slaked (hydrated) lime is used to convert (causticize) sodium carbonate into sodium hydroxide, whereby lime mud (calcium carbonate) precipitates from the solution. Lime mud is dried and reburned in a lime kiln, where burned lime (calcium oxide) is formed. The circle is closed when lime is slaked (hydrated) in green liquor in an exotherm reaction. Problems with traditional slaking method is that heat is recovered at low temperatures. With the method described in this report there is potential to increase heat recovery in the causticizing plant. The forecasted method means that lime is slaked with steam or humid air, for example combined with a lime mud drier and a lime kiln. The task has included slaking of burned lime with steam or humid hot air, on purpose to test a specific machine equipment in pilote scale, and to investigate temperatures and hydratization rates able to reach. Also the lime slaked with steam/humid air should be compared with burned lime slaked in green liquor when green liquor is causticized, and to investigate the dewatering properties of formed lime mud. The target group is pulp and paper industry using the kraft process. The tests have been performed at SMA Svenska Mineral AB plant (lime burning) at Sandarne Sweden in years 2004-2005. Hydrated lime of varying slaking rates has been produced at temperatures up to 270 deg C. Caustizicing being performed show that dewatering properties of lime mud formed is quite up to the standard of lime mud from burned lime slaked in green liquor. The apprehension, that the hygroscopic slaked lime should result in lime mud difficult to dewater, has not become true. Important experiences have come out which could be used as a base in further investigations.

Effects of curing time and line addition on the microstructure and physical properties of hydrated burnt clay-lime mixes

International Nuclear Information System (INIS)

Hajjaji, M.; Mleza, Y.

2012-01-01

The change of the microstructure of hydrated burnt illitic-kaolinitic clay-lime blends as a fonction of curing time and line addition were investigated using X-ray diffraction and scanning electron microscope. The relation between physical properties - bending strenght, density and water absorption - and the operating factors were formulated using response surface methodology. It was found that floculation-agglomeration, carbonation and hydrates formation where the main happening transformations. The pozzolanic reactions essentially involved metakaolin, derived from heated kaolinite. Based on the RSM results, both factors had positive effects on the strength and their interactions were synergistic. However, they manifested opposite effects and significant antaginistic interactions on density and water absorption

Effect of hydrated lime and cement on moisture damage of recycled mixtures with foamed bitumen and emulsion

OpenAIRE

Nosetti, R.A.; Pérez Jiménez, Félix Edmundo; Martínez Reguero, Adriana Haydée; Miró Recasens, José Rodrigo

2016-01-01

Cold recycling with foamed bitumen can be used as a sustainable and cost-effective rehabilitation technique. This paper focuses on the evaluation of the resistance to the water action in mixtures with reclaimed asphalt pavement (RAP) and foamed bitumen by means of indirect tensile test, comparing the effect of two active fillers: cement and hydrated lime. Additionally, mixtures recycled with RAP and asphalt emulsions were also tested in order to compare the response of both technologies. Resu...

Simulation of the self-healing of dolomitic lime mortar

NARCIS (Netherlands)

Lubelli, B.; Nijland, T.G.; Hees, R.P.J. van

2012-01-01

A test procedure was set up to reproduce laboratory self-healing on lime-based (both pure calcium and magnesium-calcium) mortar specimens. After a few months of testing, during which time the specimens were submitted to wet-dry cycles, thin sections of the specimens were prepared and observed using

Lime utilization in the laboratory, field, and design of pavement layers : final report.

Science.gov (United States)

2017-01-01

The objective of this study was to review and report the best practices of using lime (i.e., granulated lime, hydrated lime, and slurry lime) to dry soil, in working tables, and in pavement applications. The project also reviewed and documented the i...

Internal friction of hydrated soda-lime-silicate glasses.

Science.gov (United States)

Reinsch, S; Müller, R; Deubener, J; Behrens, H

2013-11-07

The internal friction of hydrated soda-lime-silica glasses with total water content (C(W)) up to 1.9 wt. % was studied by dynamic mechanical analysis (DMA) using temperature-frequency sweeps from 723 K to 273 K and from 1 s(-1) to 50 s(-1). Total water content and concentrations of H2O molecules (C(H2O)) and OH groups (C(OH)) in the DMA specimens were determined by infrared spectroscopy. For low water contents (C(W) ≈ C(OH) friction peaks below the glass transition (α relaxation) were assigned to the low-temperature motion of alkali ions (γ relaxation) and cooperative movements of dissimilar mobile species under participation of OH at higher temperature (β(OH) relaxation). For large water contents (C(W) > 1 wt. %), where significant amounts of molecular water are evident (C(H2O) > 0.15 wt. %), however, internal friction spectra change unexpectedly: the β(OH) peak heights saturate and a low temperature shoulder appears on the β-relaxation peak. This emerging relaxation mode (β(H2O) relaxation) was assigned to the motions of H2O molecules. β(H2O) relaxation was found to be faster than β(OH) but slower than γ relaxation. Activation energy of the different relaxation modes increased in the order γ < β(H2O) < β(OH) < α.

Hygroscopic slaking of lime with steam or humid air. New energy effective lime slaking technology in kraft pulping; Hygroskopisk slaeckning av kalk med aanga eller fuktig luft. Ny energieffektiv teknik foer slaeckning av mesakalk i sulfatmassaindustrin

Energy Technology Data Exchange (ETDEWEB)

Lundqvist, Roland

2003-07-15

Lime stone is widely used in chemical recovery for regeneration of white liquor in kraft pulping. Slaked (hydrated) lime is used to convert (causticize) sodium carbonate into sodium hydroxide, whereby lime mud (calcium carbonate) precipitates from the solution. Lime mud is dried and reburned in a lime kiln, where burned lime (calcium oxide) is formed. The circle is closed when lime is slaked (hydrated) in green liquor in an exotherm reaction. Problems with traditional slaking method is that heat is recovered at low temperatures. With the method described in this report there is potential to increase heat recovery in the causticizing plant. The forecasted method means that lime is slaked with steam or humid air, for example combined with a lime mud drier and a lime kiln. The task has included slaking of burned lime with steam or humid hot air, on purpose to test a specific machine equipment in pilote scale, and to investigate temperatures and hydratization rates able to reach. Also the lime slaked with steam/humid air should be compared with burned lime slaked in green liquor when green liquor is causticized, and to investigate the dewatering properties of formed lime mud. The target group is pulp and paper industry using the kraft process. The tests have been performed at SMA Svenska Mineral AB plant (lime burning) at Sandarne Sweden in years 2004-2005. Project owner has been the Swedish company Torkapparater AB, and the project is performed inside the 'Vaermeforsk Program for Pulp and Paper Industry 2004-2005'. Other partners, besides SMA Svenska Mineral AB, has been Stora Enso Skoghalls Bruk, Carnot AB, AaF Process AB and KTH Energiprocesser. Hydrated lime of varying slaking rates has been produced at temperatures up to 270 deg C. Caustizicing being performed show that dewatering properties of lime mud formed is quite up to the standard of lime mud from burned lime slaked in green liquor. The apprehension, that the hygroscopic slaked lime should result

Advanced treatment technique for swine wastewater using two agents: Thermally polymerized amorphous silica and hydrated lime for color and phosphorus removal and sulfur for nitrogen removal.

Science.gov (United States)

Hasegawa, Teruaki; Kurose, Yohei; Tanaka, Yasuo

2017-10-01

The efficacy of advanced treatment of swine wastewater using thermally polymerized, modified amorphous silica and hydrated lime (M-CSH-lime) for color and phosphorus removal and sulfur for nitrogen removal was examined with a demonstration-scale treatment plant. The color removal rate was approximately 78% at M-CSH-lime addition rates of > 0.055 wt/v%. The PO43--P removal rate exceeded 99.9% with > 0.023 wt/v%. pH of the effluent from the M-CSH-lime reactor increased with the addition rate till a maximum value of 12.7, which was effective in disinfection. The recovered M-CSH-lime would be suitable as a phosphorus fertilizer because the total P 2 O 5 content was approximately 10%. The nitrogen oxide (NOx-N) removal rate by sulfur denitrification increased to approximately 80% when the NOx-N loading rate was around 0.1 kg-N/ton-S/day. It was suggested that the combination of the two processes would be effective in the advanced treatment of swine wastewater. © 2017 Japanese Society of Animal Science.

Lime and gypsum application on the wheat crop

Directory of Open Access Journals (Sweden)

Caires Eduardo Fávero

2002-01-01

Full Text Available Root growth and crop yield can be affected by chemical modifications of the soil profile owing to lime and gypsum applications. A field trial was carried out on a dystrophic Clayey Rhodic Hapludox at Ponta Grossa, PR, Brazil, aiming to evaluate lime (without or with incorporation into the soil and gypsum effects on root growth, mineral nutrition and grain yield of wheat (cv. OR 1. A randomized complete block design was used, with three replications, in a split-plot experiment. Treatments with dolomitic limestone (without lime and 4.5 t ha-1 of lime applied on the surface, in total rate and 1/3 of the requirement per year during 3 years, or incorporated into the soil were applied in July 1998 (main plots and the rates of gypsum (0, 3, 6 and 9 t ha-1 in October 1998 (subplots. Wheat was evaluated in the 2000 winter season. In conditions of water deficit absence, there was no limitation in root growth in depth, for exchangeable Ca of 6 mmol c dm-3. Lime incorporation of lime increased the Mg concentration in the leaves, but wheat yield was not influenced by the correction of soil acidity through liming treatments. Gypsum increased the concentrations of Ca and S in wheat leaves, with significant effects on grain yield. The critical level of S-SO4(2- in the 0-20 cm soil layer, extracted by ammonium acetate 0.5 mol L-1 in acetic acid 0.25 mol L-1, was 25.8 mg dm-3.

Metal Sorption to Dolomite Surfaces

International Nuclear Information System (INIS)

Brady, P.V.; Papenguth, H.W.; Kelly, J.W.

1999-01-01

Potential human intrusion into the Waste Isolation Pilot Plant (WIPP) might release actinides into the Culebra Dolomite where sorption reactions will affect of radiotoxicity from the repository. Using a limited residence time reactor the authors have measured Ca, Mg, Nd adsorption/exchange as a function of ionic strength, P CO2 , and pH at 25 C. By the same approach, but using as input radioactive tracers, adsorption/exchange of Am, Pu, U, and Np on dolomite were measured as a function of ionic strength, P CO2 , and pH at 25 C. Metal adsorption is typically favored at high pH. Calcium and Mg adsorb in near-stoichiometric proportions except at high pH. Adsorption of Ca and Mg is diminished at high ionic strengths (e.g., 0.5M NaCl) pointing to association of Na + with the dolomite surface, and the possibility that Ca and Mg sorb as hydrated, outer-sphere complexes. Sulfate amplifies sorption of Ca and Mg, and possibly Nd as well. Exchange of Nd for surface Ca is favored at high pH, and when Ca levels are low. Exchange for Ca appears to control attachment of actinides to dolomite as well, and high levels of Ca 2+ in solution will decrease Kds. At the same time, to the extent that high P CO2 increase Ca 2+ levels, JK d s will decrease with CO 2 levels as well, but only if sorbing actinide-carbonate complexes are not observed to form (Am-carbonate complexes appear to sorb; Pu-complexes might sorb as well; U-carbonate complexation leads to desorption). This indirect CO 2 effect is observed primarily at, and above, neutral pH. High NaCl levels do not appear to affect to actinide K d s

Effect of dolomite and biochar addition on N2O and CO2 emissions from acidic tea field soil.

Science.gov (United States)

Oo, Aung Zaw; Sudo, Shigeto; Akiyama, Hiroko; Win, Khin Thuzar; Shibata, Akira; Yamamoto, Akinori; Sano, Tomohito; Hirono, Yuhei

2018-01-01

A laboratory study was conducted to study the effects of liming and different biochar amendments on N2O and CO2 emissions from acidic tea field soil. The first experiment was done with three different rates of N treatment; N 300 (300 kg N ha-1), N 600 (600 kg N ha-1) and N 900 (900 kg N ha-1) and four different rates of bamboo biochar amendment; 0%, 0.5%, 1% and 2% biochar. The second experiment was done with three different biochars at a rate of 2% (rice husk, sawdust, and bamboo) and a control and lime treatment (dolomite) and control at two moisture levels (50% and 90% water filled pore space (WFPS)). The results showed that dolomite and biochar amendment significantly increased soil pH. However, only biochar amendment showed a significant increase in total carbon (C), C/N (the ratio of total carbon and total nitrogen), and C/IN ratio (the ratio of total carbon and inorganic nitrogen) at the end of incubation. Reduction in soil NO3--N concentration was observed under different biochar amendments. Bamboo biochar with the rates of 0.5, 1 and 2% reduced cumulative N2O emission by 38%, 48% and 61%, respectively, compare to the control soil in experiment 1. Dolomite and biochar, either alone or combined significantly reduced cumulative N2O emission by 4.6% to 32.7% in experiment 2. Reduction in N2O production under biochar amendment was due to increases in soil pH and decreases in the magnitude of mineral-N in soil. Although, both dolomite and biochar increased cumulative CO2 emission, only biochar amendment had a significant effect. The present study suggests that application of dolomite and biochar to acidic tea field soil can mitigate N2O emissions.

Transport of barium through dolomite rocks under the presence of guar gum and brine salinities of hydraulic fracturing wastewater

Science.gov (United States)

Ebrahimi, P.; Vilcaez, J.

2017-12-01

Hydraulic fracturing wastewater (HFW) containing high concentrations of Ba, is commonly disposed into the deep saline aquifers. We investigate the effect of brine salinity, competing cations (Ca and Mg), and guar gum (most common fracturing viscosifier) on the sorption and transport of Ba through dolomite rocks. To this aim, we have conducted batch sorption and core-flooding experiments at both ambient (22°C) and deep subsurface (60°C) temperature conditions. The effect of mineral composition is assessed by comparing batch and core-flooding experimental results obtained with sandstone and dolomite rocks. Batch sorption experiments conducted using powdered dolomite rocks (500-600 µm particle size) revealed that Ba sorption on dolomite greatly decreases with increasing brine salinity (0 - 180,000 mg-NaCl/L), and that at brine salinities of HFW, chloro-complexation reactions between Ba and Cl ions and changes in pH (that results from dolomite dissolution) are the controlling factors of Ba sorption on dolomite. Organo-complexation reactions between Ba and guar gum, and competition of Ba with common cations (Ca and Mg) for hydration sites of dolomite, play a secondary role. This finding is in accordance with core-flooding experimental results, showing that the transport of Ba through synthetic dolomite rocks of high flow properties (25-29.6% porosity, 9.6-13.7 mD permeability), increases with increasing brine salinity (0-180,000 mg-NaCl/L), while the presence of guar gum (50-500 mg/L) does not affect the transport of Ba. On the other hand, core-flooding experiments conducted using natural dolomite core plugs (6.5-8.6% porosity, 0.06-0.3 mD permeability), indicates that guar gum can clog the pore throats of tight dolomite rocks retarding the transport of Ba. Results of our numerical simulation studies indicate that the mechanism of Ba sorption on dolomite can be represented by a sorption model that accounts for both surface complexation reactions on three distinct

Petrography, trace element geochemistry, and dolomitization model - Jhimpir dolomite, Sindh, Pakistan

International Nuclear Information System (INIS)

Naseem, S.; Sheikh, S.A.

2004-01-01

Dolomites of Jhimpir area have been examined petrographically and geochemically to observe and characterize the process and extent of dolomitization. These are petrographically classified as calcitic dolomite and dolomitic limestones. The texture of dolomite is idiotopic. Most of the dolomite rhombohedrons are fine to medium gained and zoned. The replacement of biomicritic carbonate rocks (Laki Limestone of Early Eocene age) by Mg and Fe-rich solutions is observed in thin section. Major and trace elements have been analyzed in order to assess the compatibility of these elements with dolomite. The average MgO content in the samples close to small fault is between 16 and 17 % and decreases from the fault outwards, down to 5 to 4 %. The Fe, Mn, Na and K contents exhibit a positive correlation with increasing dolomitization, whereas, it correlates inversely with Sr. This paper provides evidence that the dolomites of the Jhimpir area are derived from epigenetic replacement. (author)

Effect of the preparation of lime putties on their properties.

Science.gov (United States)

Navrátilová, Eva; Tihlaříková, Eva; Neděla, Vilém; Rovnaníková, Pavla; Pavlík, Jaroslav

2017-12-08

In the study of lime as the basic component of historical mortars and plasters, four lime putties prepared from various kinds of lime of various granulometry and by various ways of preparation were evaluated. The rheological properties and micro-morphologic changes, growing of calcite crystals, and rate of carbonation were monitored. The lime putty prepared from lump lime achieves the best rheological properties, yield stress 214.7 Pa and plastic viscosity 2.6 Pa·s. The suitability of this lime putty was checked by testing the development of calcium hydroxide and calcite crystals using scanning electron microscopy and environmental scanning electron microscopy. The disordered crystals of calcium hydroxide exhibit better carbonation resulting in the large crystals of calcite; therefore, the mortar prepared from the lump lime has the highest flexural strength and compressive strength 0.8/2.5 MPa, its carbonation is the fastest and exhibits the longest durability. Also, thanks to the micro-morphological characterization of samples in their native state by means of environmental scanning electron microscopy, the new way of lime putty preparation by mixing was proven. The preparation consists in the mechanical crash of the lime particles immediately after hydration. This enables the properties of putty prepared from lump lime to be nearly reached.

Characterization of the Lime Mortars of the Rui Barbosa House Museum in Rio De Janeiro, Brazil

Directory of Open Access Journals (Sweden)

Daniele Pereira da Silva Dalto

2018-02-01

Full Text Available The aim of this research is to characterize the mortars of the Rui Barbosa House Museum, built in 1850, in the city of Rio de Janeiro, Brazil, using X-ray diffraction (XRD, gel-CSH determination, Fourier Transform Infrared spectrometry (FTIR, Wavelength-Dispersive X-ray Fluorescence spectrometry (WDXRF, Thermo gravimetric analysis (TG-DTG, and granulometric analysis. Also, petrographic and physical characteristics such as porosity, water absorption, and apparent density of the mortars were used to identify the raw materials employed in their preparation. Mineralogical associations found are similar (quartz, calcite, kaolinite, microcline, muscovite, and albite for the majority of samples and only vary in their proportions; the most prominent phases are quartz and calcite. The collected data, indicating that the binder is hydrated lime, lead us to conclude that the analyzed samples are lime mortars, discarding the possibility of cement as the binder material. Two samples, located on the corner of the building, which underwent repairs, present a differentiated behavior, with high levels of dolomite and the presence of pozzolanic material, with greater water absorption and higher density, indicating the use of a different mortar type. In addition, it was verified that the WDXRF and XRD methods are able to determine the trace element composition with comparable precision with respect to the methodological approach proposed by Teutonico (1988. In addition, it has been verified that the major pollutant causing degradation of building are sulfur emitted by the vehicles and saline spray.

The Tonian Beck Spring Dolomite: Marine dolomitization in a shallow, anoxic sea

Science.gov (United States)

Shuster, Alice Mary; Wallace, Malcolm William; van Smeerdijk Hood, Ashleigh; Jiang, Ganqing

2018-06-01

The reason for the abundance of dolomite lithologies in Earth's early geological record compared to modern environments remains contentious. This study provides new insight into this Precambrian "dolomite problem" by revisiting one of the most controversial dolomite localities, the Beck Spring Dolomite, of Death Valley, USA. Consistent with some previous studies, petrographic evidence indicates that although the Beck Spring Dolomite now consists almost entirely of dolomite, it was originally precipitated largely as aragonite and high-Mg calcite. Depositional constituents (microbialites and ooids) were likely originally aragonitic, and early marine length-fast cements (now dolomite) are suggested to have precipitated as high-Mg calcite then replaced syntaxially by dolomite. Based on petrographic and geochemical evidence, we suggest that marine dolomitization was the dominant synsedimentary diagenetic process in the unit, and for the most part, involved syntaxial and mimetic replacement. Further, a length-slow fibrous dolomite generation was precipitated during the later stages of marine diagenesis as a primary marine dolomite cement. This is indicated by the length-slow crystallographic structure of the cement and from its preserved geochemical and cathodoluminescence growth zonation. This new evidence for Tonian marine dolomite precipitation reinforces the idea of Precambrian marine environmental conditions, including the chemical composition of seawater, promoting dolomite formation at this time. The trace metal geochemical composition of well-preserved marine components, especially dolomite marine cements, reveals information about redox conditions in this Tonian shallow seawater. In terms of rare earth element geochemistry, the Beck Spring Dolomite has no significant Ce anomaly, and a ubiquitous positive Eu anomaly, consistent with widespread oceanic anoxia during deposition. Furthermore, the relatively low levels of iron and chalcophile elements Co, Cu, Pb and

The effect of mixed liming and NPK fertilizer to yield of some rice varieties on new openings of acid sulfate tidal swamp land

Science.gov (United States)

Akhmad, A.; Dewi, W. S.; Sagiman, S.; Suntoro

2018-03-01

The strategies to meet the staple food needs in Indonesia is to open new paddy fields in the sub-optimal land. The research aims to get adaptive rice varieties with the highest yield on new openings of the acid sulfate tidal swamp applying mixed liming and NPK fertilizer. The experiment was conducted in a greenhouse at the Faculty of Agriculture, Tanjungpura University, Pontianak. The trials used a factorial completely randomized block design consisting of two factors. The first factor is a mixture of dolomite with NPK fertilizer, consisting of 3 levels (1 ton/ha dolomite and 60 kg/ha NPK; 2 ton/ha dolomite and 90 kg/ha of NPK, and 3 ton/ha dolomite and 120 kg/ha NPK). The second factor is rice varieties, consisting of 6 levels (Ciherang, Situ Bagendit, Inpara, Mira, Si Randah and Ringkak Janggut). Each treatment replicated four times. The results showed that the application of a mixture of 3 ton/ha dolomite and 120 kg/ha of NPK fertilizer showed the best results to improve rice yield on new opening of the acid sulfate tidal swap. Local rice varieties, Ringkak Janggut, applied 3 ton/ha dolomite and 120 kg/ha NPK fertilizer showed the best result of 1000 seed weight, i.e., 28.19 g, and total grain amount per panicle is 110.75 grains, with the lowest number of empty grains. Local rice varieties Ringkak Janggut potential to be developed as superior varieties on new opening acid sulfate tidal swamps by applying liming and fertilizer.

Fabric Preserving and Fabric Destroying Dolomitization: A case of Seawater Dolomitization

Directory of Open Access Journals (Sweden)

Alham Jassim Al-Langawi

2006-06-01

Full Text Available This study is based on field, petrographic and geochemical investigations of Hajar Supergroup autochthonous rocks: Ruus Al Jibal Group- Musandam Peninsula, and Akhdar Group- Jebel Akhdar, Oman and U.A.E., and para-autochthonous Maqam Formation-Sumeini Group-Jebel Sumeini-U.A.E.  Petrographic evidence indicates that the rocks were deposited in a shallow marine shelf environment, particularly tidal flat, lagoon, reef, back-reef and shoal environments that were part of the Arabian Platform during Permian and Triassic times. However, they are almost entirely dolomitized and the rocks show different petrographic features ranging from perfect preservation of original texture by mimetic dolomitization to complete obliteration and destruction of the original limestones giving rise to inequicrystalline and equicrystalline fabrics.  Dolomites analyzed by geochemical methods were categorized on the basis of textural variations; crystal size, shape and impurity or inclusion distribution within crystals, and whether these crystals are found as rock forming (replacive or cements. The dolomites display variations in stoichiometry, ordering and trace element concentrations indicating differences in dolomitizing fluid chemistry and recrystallization stages that prevailed through time. It indicates also that although dolomitization is pervasive, dolomites are petrographically and chemically immature. All the petrographic and geochemical evidence strongly indicates seawater and/or mixing zone dolomitization which may have been initiated soon after deposition of the host sediments.  Rocks showing preservation of allochems as well as the marine cements by mimetic dolomite crystals, suggest that dolomitization was early (at shallow depths with very active marine-water circulation and occurred in a relatively short time.  Evidence from crystalline dolomites indicates several crystallization events at shallow burial depths, under marine waters modified by increased

Influence of ameliorating soil acidity with dolomite on the priming of soil C content and CO2 emission.

Science.gov (United States)

Shaaban, Muhammad; Wu, Lei; Peng, Qi-An; van Zwieten, Lukas; Chhajro, Muhammad Afzal; Wu, Yupeng; Lin, Shan; Ahmed, Muhammad Mahmood; Khalid, Muhammad Salman; Abid, Muhammad; Hu, Ronggui

2017-04-01

Lime or dolomite is commonly implemented to ameliorate soil acidity. However, the impact of dolomite on CO 2 emissions from acidic soils is largely unknown. A 53-day laboratory study was carried out to investigate CO 2 emissions by applying dolomite to an acidic Acrisol (rice-rapeseed rotation [RR soil]) and a Ferralsol (rice-fallow/flooded rotation [RF soil]). Dolomite was dosed at 0, 0.5, and 1.5 g 100 g -1 soil, herein referred to as CK, L, and H, respectively. The soil pH (H2O) increased from 5.25 to 7.03 and 7.62 in L and H treatments of the RR soil and from 5.52 to 7.27 and 7.77 in L and H treatments of the RF soil, respectively. Dolomite application significantly (p ≤ 0.001) increased CO 2 emissions in both RR and RF soils, with higher emissions in H as compared to L dose of dolomite. The cumulative CO 2 emissions with H dose of dolomite were greater 136% in the RR soil and 149% in the RF soil as compared to CK, respectively. Dissolved organic carbon (DOC) and microbial biomass carbon (MBC) increased and reached at 193 and 431 mg kg -1 in the RR soil and 244 and 481 mg kg -1 in the RF soil by H treatments. The NH 4 - -N and NO 3 - -N were also increased by dolomite application. The increase in C and N contents stimulated microbial activities and therefore higher respiration in dolomite-treated soil as compared to untreated. The results suggest that CO 2 release in dolomite-treated soils was due to the priming of soil C content rather than chemical reactions.

Steam slaking of lime - kinetics and technology. New energy effective lime slaking technology in kraft pulping; Aangslaeckning av kalk - kinetik och teknik. Ny energieffektiv teknik foer slaeckning av mesakalk i sulfatmassaindustrin

Energy Technology Data Exchange (ETDEWEB)

Lundqvist, Roland

2008-06-15

Lime stone is widely used in chemical recovery for regeneration of white liquor in kraft pulping. Slaked (hydrated) lime is used to convert (causticize) sodium carbonate into sodium hydroxide, whereby lime mud (calcium carbonate) precipitates from the solution. Lime mud is dried and reburned in a lime kiln, where burned lime (calcium oxide) is formed. The circle is closed when lime is slaked (hydrated) in green liquor in an exotherm reaction. Problems with traditional lime burning and slaking methods are that heat recovery is bad and heat is recovered at low temperatures. With the method described in this report there is potential to increase heat recovery in the causticizing plant, and to recover heat at higher temperatures. The forecasted method means that lime is slaked with water vapour, for example combined with an indirect heated lime mud drier and a lime kiln. This project is a follow-up to pilot tests performed in a specific machine equipment at year 2006. The target group is pulp and paper industry using the kraft process. The owner of this new project is Carnot AB and the project is performed inside the Vaermeforsk Program for Pulp and Paper Industry 2006-2008. Partners and advisers in project group have been KTH Energy Processes, CTH Energy and Environment, LTH Chemical Technology, SMA Mineral AB, and reference group from STORA Enso Skoghall, Sodra Cell, M-Real Husum and SCA Packaging Piteaa. The task in this stage has included market investigations and laboratory tests. Contacts have been made with suppliers, preliminary dimensioning of process equipment and budget offers are received. Economic calculations have been made out of the offers. The laboratory tests are done as an examination paper at KTH Energiprocesser on the reactivity of burned lime from kraft lime kiln when it is slaked with water vapour instead of green liquor. The vapour intended to be used is at atmospheric pressure or even down to 0,2 atm. Complementary addition to these laboratory

Terrestrial liming benefits birds in an acidified forest in the northeast.

Science.gov (United States)

Pabian, Sarah E; Brittingham, Margaret C

2007-12-01

Studies in Europe have reported negative effects of acid deposition on forest birds, and research in North America has identified links between forest bird abundance and rates of acid deposition. We examined the bird community in an acidified forest in central Pennsylvania (USA) and evaluated the effects of terrestrial lime application on birds. We used a before-after control-impact (BACI) study design, with one year of observation before (2003) and three years after lime application (2004, 2005, and 2006). Between the 2003 and 2004 field seasons, 4500 kg/ha of dolomitic lime were applied to two of four 100-ha watersheds. Each year, we monitored bird abundance and Ovenbird (Seiurus aurocapilla) eggshell thickness and territory size. Soil and snail abundance data were also collected. The bird community and territory size results indicated that the study area may be providing low-quality habitat for forest birds, perhaps as a result of acid deposition. We found lower forest bird abundances than have been found in less acidified areas of Pennsylvania, and larger Ovenbird territory sizes than have been found in other studies. We found a significant positive relationship between soil calcium and bird abundance, indicating that soil calcium may affect bird abundance. Liming increased soil calcium and pH and led to increased snail and bird abundances. After liming, bird abundance was positively related to snail abundance. No significant changes occurred in Ovenbird territory size or eggshell thickness. Our results suggest that acid deposition could be responsible for reduced bird abundance, and that liming is a potential mitigation technique.

Effect of Lime Addition Methods on Performance Related Properties of Asphalt Concrete Mixture

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Amjad Hamd Khalil Albayati

2016-09-01

Full Text Available In the recent years, some of the newly constructed asphalt concrete pavements in Baghdad as well as other cities across Iraq showed premature failures with consequential negative impact on both roadway safety and economy. Frequently, load associated mode of failure (rutting and fatigue as well as, occasionally, moisture damage in some poorly drained sections are the main failure types found in those newly constructed road. In this research, hydrated lime was introduced into asphalt concrete mixtures of wearing course in two methods. The first one was the addition of dry lime on dry aggregate and the second one was the addition of dry lime on saturated surface dry aggregate moisturized by 2.0 to 3.0 percent of water. For each type of addition, five different percentages of lime as a partial replacement of ordinary limestone mineral filler were used; these were; 1.0, 1.5, 2.0, 2.5, and 3 percent by weight of aggregate besides a control mixture that did not contain lime. Marshall Mix design method was used and the performance properties of moisture damage, resilient modulus, permanent deformation and fatigue characteristics were evaluated using indirect tensile strength, uniaxial repeated loading and repeated flexural beam tests. Also, VESYS5W software was implemented to evaluate the pavements performance in terms of rut depth and fatigue area for a typical pavement structure. The main conclusion withdrawn from this research revealed that the use of 2.5 percent hydrated lime in dry addition method and wet addition method showed an improved fatigue and permanent deformation characteristics, lower moisture susceptibility and high resilient modulus.

Optimization of lime addition in a dry air pollution control device; Optimerad rening av HCl och SO{sub 2} med minskade kalktillsatser vid torr roeasrening

Energy Technology Data Exchange (ETDEWEB)

Wikstroem-Blomqvist, Evalena; Samuelsson, Jessica; Ohlsson, Anna

2006-12-15

The focus of this project is to optimize the absorption of hydrochloric acid (HCl) and sulphuric acid (SO{sub 2}) in a dry air pollution control device system connected to a waste combustor. A significant amount of absorbent are generally added into the processes to achieve an efficient cleaning of the flue gas. Reduced absorbent consumption has double benefits on the operative expenses due to decreased purchase and landfilling costs. The objective was to study the affect of flue gas temperature and moisture, (relative humidity, RH), on the efficiency of HCl and SO{sub 2} absorption on hydrated lime. Additionally, the efficiency of a pre-treated hydrated lime with larger specific surface and pore volume was investigated. The measuring campaign was conducted on the 20 MW fluidized bed waste incinerator own by Boraas Energi och Miljoe AB in Sweden. Results from 26 experimental days with normal hydrated lime showed a positive correlation between the efficiency of the lime and RH in the flue gas. Four levels of RH between 3.28% to 4.84% were tested. The levels were adjusted by lowering the flue gas temperature and/or by adding water to the waste fuel. The smallest effect where achieved by solely adding water to the waste fuel. RH increased solely to 3.62% and the amount of lime consumption was reduced with only 5% compare to normal condition. By lowering the flue gas temperature 10 deg C to 143 deg C, RH increased to 4.06% and the amount of lime added was reduced with 13%. The largest impact was found when both the flue gas temperature and the moisture content were changed. At those process conditions RH reach 4.84 % and the usage of lime were reduced with 26%. Additional 12 experimental days were conducted to evaluate the efficiency of a pretreated hydrated lime with larger specific surface and pore volume. The results showed that the surface enlarged absorbent was almost twice as effective as the normal hydrated lime. Moreover, the results indicated an equal

Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

Directory of Open Access Journals (Sweden)

Sarah E Pabian

Full Text Available Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

Wood ash or dolomite treatment of catchment areas - effects of mercury in runoff water

Energy Technology Data Exchange (ETDEWEB)

Parkman, H; Munthe, J [Swedish Environmental Research Inst., Stockholm (Sweden)

1996-11-01

A future increased use of biomass as a source of energy, and the planned restoration of mineral nutrient balance in the forest soils by returning the wood ashes, has led to concern for new environmental disturbances. The objectives of the present study were to investigate if the outflow of total mercury (TotHg) and methyl mercury (MeHg) from catchment areas treated with granulated wood ash (1988, 2.2 tons/ha, `ashed area`) or dolomite (1985, 5 tons/ha, `limed area`) differed from the outflow from an untreated (reference) area, and if variations in Hg outflow were correlated with changes in the outflow of organic substances or pH. The study areas are situated in Vaermland, Sweden. Samples of run-off water were taken weekly or monthly (depending on water-flow) during on year (1993-94). The outflow of MeHg, TotHg as well as H+ and dissolved organic material (DOC) was lower from the limed area compared to the other two areas, which did not differ significantly. There was a strong covariation between concentrations of DOC and MeHg and a weaker relation between DOC and TotHg in the run-off waters. MeHg also covaried with temperature while TotHg covaried with pH and water-supply. No difference was found when comparing Hg-data from the limed area before, directly after and eight years after the liming event. 13 refs, 12 figs, 1 tab

Lactic Acid Fermentation, Urea and Lime Addition: Promising Faecal Sludge Sanitizing Methods for Emergency Sanitation.

Science.gov (United States)

Anderson, Catherine; Malambo, Dennis Hanjalika; Perez, Maria Eliette Gonzalez; Nobela, Happiness Ngwanamoseka; de Pooter, Lobke; Spit, Jan; Hooijmans, Christine Maria; de Vossenberg, Jack van; Greya, Wilson; Thole, Bernard; van Lier, Jules B; Brdjanovic, Damir

2015-10-29

In this research, three faecal sludge sanitizing methods-lactic acid fermentation, urea treatment and lime treatment-were studied for application in emergency situations. These methods were investigated by undertaking small scale field trials with pit latrine sludge in Blantyre, Malawi. Hydrated lime was able to reduce the E. coli count in the sludge to below the detectable limit within 1 h applying a pH > 11 (using a dosage from 7% to 17% w/w, depending faecal sludge alkalinity), urea treatment required about 4 days using 2.5% wet weight urea addition, and lactic acid fermentation needed approximately 1 week after being dosed with 10% wet weight molasses (2 g (glucose/fructose)/kg) and 10% wet weight pre-culture (99.8% pasteurised whole milk and 0.02% fermented milk drink containing Lactobacillus casei Shirota). Based on Malawian prices, the cost of sanitizing 1 m³ of faecal sludge was estimated to be €32 for lactic acid fermentation, €20 for urea treatment and €12 for hydrated lime treatment.

Characterization of Historica Lime Mortar from the Spanish Colonial Period in the Philippines

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Jan-Michael C. Cayme

2017-07-01

Full Text Available Detailed scientific research applied to the field of cultural heritage is rarely practiced in the Philippines. This study intends to present a systematic approach to the proper chemical characterization of an old lime mortar sample from a Spanish-era church ruin. The analytical techniques employed were: atomic absorption spectroscopy (AAS, infrared spectroscopy (IR, scanning electron microscopy and energy-dispersive x-ray spectroscopy (SEM-EDX, and thermogravimetric analysis (TGA. Results showed that the binder is mostly calcitic, non-dolomitic and air-hardening lime. A slight hydraulic character was observed due to possible clay impurities. Besides the typical sand mixture in mortars, crushed shell fragments were used as aggregates. Possible organic compounds were also identified. The data obtained from this study is very important in understanding traditional building techniques that can enhance heritage conservation work in the Philippines.

A study on engineering characteristics of asphalt concrete using filler with recycled waste lime.

Science.gov (United States)

Sung Do, Hwang; Hee Mun, Park; Suk keun, Rhee

2008-01-01

This study focuses on determining the engineering characteristics of asphalt concrete using mineral fillers with recycled waste lime, which is a by-product of the production of soda ash (Na(2)CO(3)). The materials tested in this study were made using a 25%, 50%, 75%, and 100% mixing ratio based on the conventional mineral filler ratio to analyze the possibility of using recycled waste lime. The asphalt concretes, made of recycled waste lime, hydrated lime, and conventional asphalt concrete, were evaluated through their fundamental engineering properties such as Marshall stability, indirect tensile strength, resilient modulus, permanent deformation characteristics, moisture susceptibility, and fatigue resistance. The results indicate that the application of recycled waste lime as mineral filler improves the permanent deformation characteristics, stiffness and fatigue endurance of asphalt concrete at the wide range of temperatures. It was also determined that the mixtures with recycled waste lime showed higher resistance against stripping than conventional asphalt concrete. It was concluded from various test results that a waste lime can be used as mineral filler and, especially, can greatly improve the resistance of asphalt concrete to permanent deformation at high temperatures.

Nutritional characteristics of two pigeon pea hybrids – Liming and phosphated fertilization

Directory of Open Access Journals (Sweden)

Marcia Atauri Cardelli de Lucena

2012-12-01

Full Text Available The use of legumes in animal production systems can be a sustainable alternative as a protein source in rotational grazing system and/or as a protein bank. Pigeon pea (Cajanus cajan (L. Millsp. figure as an example of success of this use on animal nutrition. The development of this species can be limited by the high acidity and low soil phosphorus content. There is a lack of scientific information on the effects of liming and phosphorus fertilization on some nutritional variables of two pigeon pea new hybrids. This study was conducted in pots containing 5 kg of soil in a greenhouse at the Instituto de Zootecnia, Nova Odessa, São Paulo State. There were studied two pigeon pea hybrids, H1 and H2, and the treatments involved agronomic practices: 1 No liming and without phosphorus (control, 2 Liming (L, 3 Phosphorus fertilization (P and 4 Liming plus phosphorus. Liming was proposed to increase soil base saturation to 50%, it was used dolomite lime PRNT = 90%, in an amount corresponding to 4.5 t/ha. Phosphorus fertilization (as superphosphate rate was 60 kg/ha of PO25. The experimental units were allocated according to a complete randomised block design, with five replications. We analyzed the levels of crude protein (CP, neutral detergent fiber (NDF, acid detergent fiber (ADF, in pigeon pea shoot at 45 days of age. Statistical analyzes were performed using the software SISVAR, averages were compared using test for multiple comparisons Student Newman-Keuls - SNK test (P < 0.05. The H1 hybrid had the highest content of CP, by applying P, lime plus P and the control treatment compared to H2 hybrid. The association lime plus P resulted in higher content of CP mainly due to the increased availability of P for plants. Smaller values were observed for NDF in H2 with P application. Lower values of ADF were observed in H1 in both control treatment and P application. The ADF values were lower for the hybrid H2 only for the treatment lime plus P. The two

Possibilities and limits of fertilization and melioration liming (as measures to fight 'novel' forest disease)

International Nuclear Information System (INIS)

Rehfuess, K.E.

1989-01-01

The revitalization potential of forest fertilization and liming is assessed by types of disease. Spruces on acid soils in the upper reaches of medium-range mountains have been known to exhibit specific Mg deficiency. In steep southern slopes of the Calcareous Alps a spruce disease is found where trees show nutrition disorders - acute K and Mn deficiency - with characteristic chloroses. In southern Germany, there is incidence of needle reddening as the most prominent type of disease in spruce (connection with K deficiency). Crown overthinning in spruce is likely to be caused by Mg deficiency. The paper discusses nutrition disorders in fir and beech disease. For acidic substrates, melioration liming (dolomite) is recommended. It adjusts the pH value and increases the available amounts of exchangeable Mg and Ca. (VT) [de

Experimental evaluation of sorbents for sulfur control in a coal-fueled gas turbine slagging combustor

International Nuclear Information System (INIS)

Cowell, L.H.; Wen, C.S.; LeCren, R.T.

1992-01-01

This paper reports on a slagging combustor that has been used to evaluate three calcium-based sorbents for sulfur capture efficiency in order to assess their applicability for use in a oil-fueled gas turbine. Testing is competed in a bench-scale combustor with one-tenth the heat input needed for the full-scale gas turbine. The bench-scale rig is a two-stage combustor featuring a fuel-rich primary zone an a fuel-lean secondary zone. The combustor is operated at 6.5 bars with inlet air preheated to 600 K. Gas temperatures of 1840 K are generated in the primary zone and 1280 K in the secondary zone. Sorbents are either fed into the secondary zone or mixed with the coal-water mixture and fed into the primary zone. Dry powered sorbents are fed into the secondary zone by an auger into one of six secondary air inlet ports. The three sorbents tested in the secondary zone include dolomite, pressure-hydrated dolomitic lime, and hydrated lime. Sorbents have been tested while burning coal-water mixtures with coal sulfur loadings of 0.56 to 3.13 weight percent sulfur. Sorbents are injected into the secondary zone at varying flow rates such that the calcium/sulfur ratio varies from 0.5 to 10.0

Lime application for the efficient production of nutraceutical glucooligosaccharides from Leuconostoc mesenteroides NRRL B-742 (ATCC13146).

Science.gov (United States)

Moon, Young Hwan; Madsen, Lee; Chung, Chang-Ho; Kim, Doman; Day, Donal F

2015-02-01

We have previously demonstrated the production of glucooligosaccharides via a fermentation of sucrose with Leuconostoc mesenteroides NRRL B-742 using sodium hydroxide (NaOH) to control the pH. Because NaOH is expensive, we sought to minimize the cost of our process by substituting hydrated lime and saccharate of lime (lime sucrate) in its place. The yield of glucooligosaccharides using either 5 % lime (41.4 ± 0.5 g/100 g) or 5 % lime sucrate (40.0 ± 1.4 g/100 g) were both similar to the NaOH control (42.4 ± 1.5 g/100 g). Based on this, it appears that the cost associated with pH control in our process can be reduced by a factor of approximately 2.4 using lime instead of NaOH. Because our chromatographic stage is based on a Ca(2+)-form resin to separate glucooligosaccharides, the use of lime not only negates the need for costly de-salting via ion-exchange (elimination of two ion-exchange sections) prior to separation, but also greatly reduces the resin regeneration cost.

A urolith of biogenic dolomite - another clue in the dolomite mystery

Science.gov (United States)

Mansfield, Charles F.

1980-06-01

A male Dalmatian, Canis familiaris, produced uroliths of almost pure dolomite, 3-8 mm across, in his urinary bladder in less than 8 months at 38°C and about 1 atm. The X-ray diffractogram identified the predominant mineral as dolomite, and the sharp (01.5) peak showed it is ordered dolomite, not the disordered form, protodolomite. Geochemically and biologically plausible causes include (1) renal, respiratory, or metabolic alkalosis, (2) infection by urease-producing (urea-splitting) fungi or bacteria and (3) infection by uric acid-fermenting bacteria. Hematological, bacteriological, urological and geochemical considerations most strongly implicate infection by either anaerobic, urease-producing bacteria or anaerobic, uric acid-fermenting bacteria. The physical and chemical conditions of this urinary system more closely approximate modern and inferred ancient carbonate depositional settings than most previous laboratory experiments, especially in terms of temperature, pressure, total salinity and, possibly, biota. The presence of urease-producing and/or uric acid-fermenting bacteria in urea- and/or acid-containing sediment, such as fecal pellets and algal mats, could promote formation of authigenic dolomite or other carbonates.

Reaction kinetics of dolomite rim growth

Science.gov (United States)

Helpa, V.; Rybacki, E.; Abart, R.; Morales, L. F. G.; Rhede, D.; Jeřábek, P.; Dresen, G.

2014-04-01

Reaction rims of dolomite (CaMg[CO3]2) were produced by solid-state reactions at the contacts of oriented calcite (CaCO3) and magnesite (MgCO3) single crystals at 400 MPa pressure, 750-850 °C temperature, and 3-146 h annealing time to determine the reaction kinetics. The dolomite reaction rims show two different microstructural domains. Elongated palisades of dolomite grew perpendicular into the MgCO3 interface with length ranging from about 6 to 41 µm. At the same time, a 5-71 µm wide rim of equiaxed granular dolomite grew at the contact with CaCO3. Platinum markers showed that the original interface is located at the boundary between the granular and palisade-forming dolomite. In addition to dolomite, a 12-80 µm thick magnesio-calcite layer formed between the dolomite reaction rims and the calcite single crystals. All reaction products show at least an axiotactic crystallographic relationship with respect to calcite reactant, while full topotaxy to calcite prevails within the granular dolomite and magnesio-calcite. Dolomite grains frequently exhibit growth twins characterized by a rotation of 180° around one of the equivalent axis. From mass balance considerations, it is inferred that the reaction rim of dolomite grew by counter diffusion of MgO and CaO. Assuming an Arrhenius-type temperature dependence, activation energies for diffusion of CaO and MgO are E a (CaO) = 192 ± 54 kJ/mol and E a (MgO) = 198 ± 44 kJ/mol, respectively.

The effect of high curing temperature on the reaction kinetics in MK/lime and MK-blended cement matrices at 60 deg. C

International Nuclear Information System (INIS)

Rojas, Moises Frias; Sanchez de Rojas, M.I.

2003-01-01

It is well known that the pozzolanic reaction between metakaolin (MK) and calcium hydroxide produces CSH, C 2 ASH 8 (stratlingite), C 4 AH 13 and C 3 ASH 6 (hydrogarnet). However, the presence or absence of these hydrated phases depends on different parameters, such as curing temperature, matrix used, etc. This paper shows the results of a study in order to know the effect of high curing temperature (60 deg. C) on the kinetics of the pozzolanic reaction in different matrices. MK/lime (calcium hydroxide) and MK-blended cement matrices were studied in samples stored and cured at 60 deg. C and up to 123 days of hydration. The nature, sequence and crystallinity of the hydrated phases were analysed using differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. Results showed that the sequence and formation of the hydrated phases was different in both matrices cured at 60 deg. C. In an MK/lime matrix, C 2 ASH 8 , C 4 AH 13 and C 3 ASH 6 were the main hydrated phases; while in an MK-blended cement, stratlingite was the sole hydrated phase issued from pozzolanic reaction. The DTA and XRD data also reveal an important fact: there is no evidence of the presence of hydrogarnet in blended cements

Dolomite decomposition under CO2

International Nuclear Information System (INIS)

Guerfa, F.; Bensouici, F.; Barama, S.E.; Harabi, A.; Achour, S.

2004-01-01

Full text.Dolomite (MgCa (CO 3 ) 2 is one of the most abundant mineral species on the surface of the planet, it occurs in sedimentary rocks. MgO, CaO and Doloma (Phase mixture of MgO and CaO, obtained from the mineral dolomite) based materials are attractive steel-making refractories because of their potential cost effectiveness and world wide abundance more recently, MgO is also used as protective layers in plasma screen manufacture ceel. The crystal structure of dolomite was determined as rhombohedral carbonates, they are layers of Mg +2 and layers of Ca +2 ions. It dissociates depending on the temperature variations according to the following reactions: MgCa (CO 3 ) 2 → MgO + CaO + 2CO 2 .....MgCa (CO 3 ) 2 → MgO + Ca + CaCO 3 + CO 2 .....This latter reaction may be considered as a first step for MgO production. Differential thermal analysis (DTA) are used to control dolomite decomposition and the X-Ray Diffraction (XRD) was used to elucidate thermal decomposition of dolomite according to the reaction. That required samples were heated to specific temperature and holding times. The average particle size of used dolomite powders is 0.3 mm, as where, the heating temperature was 700 degree celsius, using various holding times (90 and 120 minutes). Under CO 2 dolomite decomposed directly to CaCO 3 accompanied by the formation of MgO, no evidence was offered for the MgO formation of either CaO or MgCO 3 , under air, simultaneous formation of CaCO 3 , CaO and accompanied dolomite decomposition

Effects of lime and wood ash on soil-solution chemistry, soil chemistry and nutritional status of a pine stand in northern Germany

International Nuclear Information System (INIS)

Ludwig, Bernard; Rumpf, Sabine; Mindrup, Michael; Meiwes, Karl-Josef; Khanna, Partap K.

2002-01-01

Lime and wood ash may be useful to improve acidic forest soils. A field experiment was conducted in a pine stand on a sandy podzol at Fuhrberg, Germany, which involved an application of dolomitic lime (3 t/ha) with three replications or wood ash (4.8 t/ha) without replications on the forest floor. During the 2 yr study period, lime affected the soil solution composition only slightly. Ash had a marked effect on solution chemistry of the mineral soil at 10 cm and the pH values dropped temporarily from 3.7 to 3.1. Nineteen months after the treatments, exchangeable calcium in the organic layer and mineral soil increased by 222 (lime addition) or 411 kg/ha (ash addition) and exchangeable magnesium increased by 101 (lime addition) or 39 kg/ha (ash addition). After ash addition, no marked change in heavy metal content was found below 4 cm of the organic layer. In the ash treatment, the potassium concentration of the 1-yr-old pine needles increased from 5.6 to 5.9 g/kg. This study suggests that ash from untreated wood may be recommended for amelioration of forest soils

Problems experiences with the construction of cement and lime stabilized layers and working solutions for these problems

CSIR Research Space (South Africa)

Botha, PB

2005-10-01

Full Text Available Stabilized layers are used extensively in South-Africa in the construction of roads. The layers are usually stabilized with hydrated road lime, cement, slag, fly-ash, bitumen emulsion, foamed asphalt or a combination of several of these agents...

Effects of surface application of dolomitic limestone and calcium-magnesium silicate on soybean and maize in rotation with green manure in a tropical region

Directory of Open Access Journals (Sweden)

Gustavo Spadotti Amaral Castro

2015-01-01

Full Text Available Although lime is currently the material most frequently used to ameliorate soil acidity in Brazil, silicate could efficiently replace this source because of its greater solubility and its greater silicon content, which are beneficial for plant development. This study aimed to evaluate the effects of superficial lime and silicate application on soil chemical attributes as well as on soybean and maize nutrition and grain yields when these crops are grown in rotation with green manure. The experimental design was a complete randomized block with sixteen replicates. Plots were treated with one of two materials for acidity correction (dolomitic lime and calcium/magnesium silicate or with no soil correction, as a control. Silicate corrected soil acidity and increased exchangeable base levels in soil at greater depths faster than does liming. The application of both acidity-correcting materials increased N, Ca and Mg leaf concentrations, and all yield components and grain yield in soybean; but in maize, just silicate also increased N and Si when compared with lime, whereas both acidity-correcting increased just two yield components: grains per ear and mass of 100 grains, resulting in highest grain yield. The application of both acidity-correcting materials increased dry matter production of green manures, but for pigeon pea the silicate provided the best result in this dry-winter region.

Chemical composition and strength of dolomite geopolymer composites

Science.gov (United States)

Aizat, E. A.; Al Bakri, A. M. M.; Liew, Y. M.; Heah, C. Y.

2017-09-01

The chemical composition of dolomite and the compressive strength of dolomite geopolymer composites were studied. The both composites prepared with mechanical mixer manufactured by with rotor speed of 350 rpm and curing in the oven for 24 hours at 80˚C. XRF analysis showThe dolomite raw materials contain fewer amounts of Si and Al but high Ca in its composition. Dolomite geopolymer composites with 20M of NaOH shows greater and optimum compressive strength compared to dolomite geopolymer with other NaOH molarity. This indicated better interaction of dolomite raw material and alkaline activator need high molarity of NaOH in order to increase the reactivity of dolomite.

Characterization of a lime-pozzolan plaster containing phase change material

International Nuclear Information System (INIS)

Pavlíková, Milena; Pavlík, Zbyšek; Trník, Anton; Pokorný, Jaroslav; Černý, Robert

2015-01-01

A PCM (Phase Change Material) modified lime-pozzolan plaster for improvement of thermal energy storage of building envelopes is studied in the paper. The investigated plaster is composed of lime hydrate, pozzolan admixture based on metakaolin and mudstone, silica sand, water and paraffin wax encapsulated in polymer capsule. The reference plaster without PCM application is studied as well. The analyzed materials are characterized by bulk density, matrix density, total open porosity, compressive strength and pore size distribution. The temperature of phase change, heat of fusion and crystallization are studied using DSC (Difference Scanning Calorimetry) analysis performed in air atmosphere. In order to get information on materials hygrothermal performance, determination of thermal and hygric properties is done in laboratory conditions. Experimental data reveal a substantial improvement of heat storage capacity of PCM-modified plaster as compared to the reference material without PCM

Grenade Range Management Using Lime for Dual Role of Metals Immobilization and Explosives Transformation. Field Demonstration at Fort Jackson, SC

Science.gov (United States)

2008-09-01

and reported the results under the sample delivery groups ( SDG ) L128026 and L128720. The following analytical methods were requested on the chains -of... supplies . The application of hydrated lime to an HGR to provide a mechanism for both metals immobilization and explosives transformation was...Offsites 1 and 2 were supplied by RDX from the control bay, Bay 2. Offsite 3 was supplied by the RDX from lime- treated Bay 4. A period of 6 months had

Weathering of dolomite in industrial environments

International Nuclear Information System (INIS)

Gauri, K.L.; Tambe, S.S.; Caner-Saltik, E.N.

1992-01-01

To the exclusion of other major atmospheric pollutants, sulfur dioxide is mainly responsible for attack upon dolomite. This article characterizes Laurel Dolomite on the basis of composition, texture, and porosity; describes the mechanism of the SO 2 reaction with dolomite; and develops two equations for the prediction of the rate of decay of dolomite. Over a period of 120 yr nearly 3.57 mm surface reduction at protected areas and 0.915 mm surface reduction at unprotected surfaces of a building in Louisville was calculated. However, these values could not be verified because measurement of these quantities in the field cannot be made

Geomechanical properties of lime stabilized clayey sands

International Nuclear Information System (INIS)

Arabani, M.; Karami, M. Veis

2007-01-01

Clayey sands that have low plasticity, low compressibility and high strength under loads, are suitable as a base material for any engineering construction projects as well as for roads and building construction. Decrease of plasticity and compressibility as well as increase in strength of these materials can be obtained by many different methods. Of these methods, lime stabilization is a common, applicable, and easy to use approach that can improve geomechanical and geotechnical properties of clayey sand fills. In this study some important geomechanical properties and geotechnical properties of clayey sands including compressive strength, CBR and elastic plastic behavior are investigated. A range of gradations representative of those gradations found in situ in the north of Iran were selected for testing and samples were artificially rebuilt in the laboratory. The mixes were then stabilized with hydrated lime and cured. Different mechanical tests were performed on mature materials. The stress-strain behavior of lime-stabilized mixes was plotted and a parabolic function was used to estimate the trend of stress-strain behavior. The data show that there is a correlation among the results of uniaxial load test, tensile strength, and CBR of the tested specimens. Also, results of the unconfined compression test and the indirect tensile strength test show that an increase in clay content up to a certain percent, in the clay-sand fills, tends to increase the strength of the materials in compression as well as in tension. (author)

Wetting behavior of magnesite and dolomite surfaces

Science.gov (United States)

Gence, Nermin

2006-03-01

Magnesite and dolomite are salt-type minerals that show similar chemical composition and flotation behavior due to same crystal structure, and sparingly soluble nature. The surface properties of minerals play a major role in determining their separation from each other in processes such as flotation. During flotation process, selectivity problem arises between magnesite and associated gangue minerals such as dolomite. There is a close relationship between floatability of minerals and their contact angles. Therefore, surface hydrophobicity of magnesite and dolomite minerals was investigated by contact angle measurements in the absence and presence of flotation reagents. Magnesite and dolomite show hydrophilic properties and they have got a small contact angle (magnesite ˜10.4° and dolomite ˜6.6°) in distilled water in the absence of any surfactant. The contact angle values at the magnesite and dolomite surfaces remained at 9.7°-10.9° in the presence of petroleum sulphonates (R825 and R840) while sodium oleate affected hydrophobicity of magnesite, and the contact angle value increased up to 79°. The contact angle value of 39° at dolomite surface was obtained in the solution of sodium oleate, respectively.

Dolomitization and over-dolomitization in the Vajont limestone (Dolomiti Bellunesi, Italy) controlled by Mesozoic normal faults: a microstructural and diagenesis study

Science.gov (United States)

Cortinovis, Silvia; Swennen, Rudy; Bistacchi, Andrea

2015-04-01

The Vajont Gorge (Dolomiti Bellunesi, Italy) provides spectacular outcrops of Jurassic limestones (Vajont Limestone Formation) in which Mesozoic faults and fracture corridors are continuously exposed. Some of these faults acted as conduits for Mg-enriched hydrothermal fluids resulting in structurally-controlled dolomitization of the limestone. The dolomitization resulted in several dolomite bodies (100-200 m thick and several hundreds of meters along fault strike) that are particularly interesting as reservoir analogues for hydrocarbon, CO2, or water-bearing systems. The dolomitization process occurred after deposition and compaction of the oolitic limestone (dolomitization post-dates a dissolution event that affected the internal parts of the oolites), but before the Alpine contractional deformation. In fact, the meso-structural data collected in the Vajont Gorge allowed the reconstruction of a 3D model showing that the circulation of the dolomitizing fluids into the limestone host rock, but also the late stage of porosity reduction (strong pore filling due to over-dolomitization) were controlled by normal faults and fracture corridors interpreted as Pre-Alpine (Jurassic or Cretaceous). Later on, the influence of Alpine (Tertiary) deformation have been very limited in the studied volume. For instance dolomite veins are sometimes overprinted by bed-inclined stylolites consistent with Alpine shortening axes, but no large Alpine fault is present in the studied outcrops. Cathodoluminescence microscopy allowed recognizing different growth stages saddle dolomite crystals, which point to varying precipitation conditions during three main stages of dolomitization. Dolomite and calcite crystal twinning suggests deformation under increasing temperature conditions, consistent with intracrystalline plasticity deformation mechanisms. The presence of cataclasites composed of hydrothermal dolostone clasts, in turn cemented by dolomite, or of dolomite veins and compaction

Strontium isotopic stratigraphy utilizing authigenic dolomites in hemipelagic sediments

Energy Technology Data Exchange (ETDEWEB)

Baker, P.A. (Duke Univ., Durham, NC (USA)); Kastner, M. (Scripps Institute of Oceanography, La Jolla, CA (USA)); Elderfield, H. (Univ. of Cambridge (England))

1990-05-01

Authigenic dolomites commonly occur in organic-rich, continental margin marine sediments. These dolomites play a key role in the age dating of stratigraphic sections. The dolomites often are the only lithology amenable to paleomagnetic stratigraphy; they preserve siliceous microfossils against diagenetic; recrystallization, and provide useful strontium isotopic stratigraphic ages. Several potential sources of error frequently are unique to the use of authigenic dolomites in the strontium isotope methods. (1) The dolomites occur as cements of the host lithology, hence, they are not a pure phase. Potentially important contaminants during analysis include gypsum clay minerals, feldspars, and iron and manganese oxides. Strontium may occur as a structural substituent ion in these minerals or as a surface-adsorbed ion. Various leaching techniques have been tested to isolate dolomitic strontium. Purer dolomites and strontium-enriched dolomites often can be selected to ease these problems. (2) The dolomites form after the deposition of the host sediment, therefore, they record the diagenetic age not the depositional age. The stable isotopic composition of the dolomites can aid in selection of early formed samples. (3) The dolomites record pore-water strontium isotope compositions, not seawater isotopic compositions. This problem is also minimized by choosing dolomites formed near the sediment-water interface. (4) The dolomites formed near the sediment-water interface originated as rotodolomites and undergo subsequent burial diagenesis, creating a potential for later strontium isotope exchange. This problem is minimized by selecting fresh samples from the interior of nearly impermeable beds and nodules. Results from the Miocene Monterey Formation of California and from the Eocene through Pliocene Pisco basin of Peru show that authigenic dolomites can provide useful strontium isotopic age estimates.

Multiple episodes of dolomitization and dolomite recrystallization during shallow burial in Upper Jurassic shelf carbonates: eastern Swabian Alb, southern Germany

Science.gov (United States)

Reinhold, C.

1998-10-01

The Upper Jurassic of the eastern Swabian Alb is composed of oolitic platform sands with associated microbe-siliceous sponge mounds at the platform margins. They are surrounded by argillaceous or calcareous mudstones and marl-limestone alternations, deposited in adjacent marl basins. Partial to complete dolomitization is predominantly confined to the mound facies. Six types of dolomite, as well as one type of ankerite, document a complex diagenetic history during shallow burial with multiple episodes of dolomite formation and recrystallization. The earliest massive matrix dolomitization is Ca-rich, has slightly depleted oxygen isotope values relative to Late Jurassic seawater, and carbon isotopic values in equilibrium with Late Jurassic seawater. This initial massive matrix dolomitization occurred during latest Jurassic to earliest Cretaceous and is related to pressure dissolution during very shallow burial at temperatures of at least 50°C. Hydrologic conditions and mass-balance calculations indicate that burial compaction provided sufficient fluids for dolomitization. Mg is derived from negligibly modified seawater, that was expelled from the adjacent off-reef strata into the mound facies. Position of the mounds along the platform margins controlled the distribution of the shallow-burial dolomite. Covariant trends between textural modification, increasing stoichiometry, partial changes in trace element content (Mn, Fe, Sr) and depletion in stable isotopes as well as distinctive CL pattern illustrate two recrystallization phases of the precursor matrix dolomite during further burial at elevated temperatures. Strong Sr enrichment of the second phase of recrystallized dolomite is ascribed to Sr-rich meteoric waters descending from overlying aragonite-bearing reef limestones or evaporite-bearing peritidal carbonates. Late-stage coarsely crystalline dolomite cements occur as vug and fracture fillings and formed during burial. Ankerite, associated with sulphide and

Cyclic, Early Diagenetic Dolomite Formation in Alkaline Lake Van

Science.gov (United States)

McCormack, J.; Bontognali, T. R. R.; Immenhauser, A.; Kwiecien, O.

2017-12-01

Modern dolomite-forming environments are commonly constrained to evaporitic marine or marginal marine settings such as lagoons and sabkhas. Beside microbial mediation, high temperatures and Mg2+ concentrations in solution are factors considered important in aiding dolomite formation. Accordingly, previous studies associate the presence of dolomite within deep sediments of alkaline Lake Van (Turkey) with periods of enhanced evaporation, low lake levels and high Mg/Ca ratio. We systematically studied dolomite within the sedimentary record of Lake Van by means of XRD, SEM and stable isotope (δ18O and δ13C) mass spectrometry. First, we considered the origin of the dolomite; next, we focused on the wider implication of its presence. SEM imaging documents large dolomite crystals interwoven with clay minerals and individual crystals with different crystallographic orientations grown together, indicating space-limited growth within the sediment. According to recent climatic reconstructions for the same sequence (ICDP PALEOVAN project), the water depth of the coring site - today at 350 m - unlikely fell below 200 m. Consequently, dolomite formed below a thick water column at constantly low temperatures (supported by heavy δ18O signature). Within this environment, variations in Mg/Ca ratio, pH and alkalinity, which are constantly high, have no effect on the episodic nature of dolomite precipitation. These observations call for a re-evaluation of the palaeoenvironments often invoked to interpret intervals rich in dolomite within ancient sedimentary sequences (e.g., periods of enhanced aridity and evaporation). Further, and in contrast to previous interpretations, our dolomite concentration data backed up by ICDP PALEOVAN reconstructions suggest that intervals rich in dolomite coincide with periods of high lake level and increased humidity. High dolomite concentrations (20 - 85 % relative carbonate content) occur cyclically within the last glacial period and coincide with

First description of Phanerozoic radiaxial fibrous dolomite

Science.gov (United States)

Richter, D. K.; Heinrich, F.; Geske, A.; Neuser, R. D.; Gies, H.; Immenhauser, A.

2014-05-01

The petrographic analysis and crystallographic analysis of concretionary carbonate cements ("coal balls") from Carboniferous paralic swamp deposits reveal the presence of (length fast) radiaxial fibrous dolomite (RFD), a fabric not previously reported from the Phanerozoic. This finding is of significance as earlier reports of Phanerozoic radiaxial fibrous carbonates are exclusively of calcite mineralogy. Dolomite concretions described here formed beneath marine transgressive intervals within palustrine coal seams. This is of significance as seawater was arguably the main source of Mg2 + ions for dolomite formation. Here, data from optical microscopy, cathodoluminescence, electron backscattered diffraction, X-ray diffraction and geochemical analyses are presented to characterize three paragenetic dolomite phases and one calcite phase in these concretions. The main focus is on the earliest diagenetic, non-stoichiometric (degree of order: 0.41-0.46) phase I, characterized by botryoidal dolomite constructed of fibres up to 110 μm wide with a systematic undulatory extinction and converging crystal axes. Petrographic and crystallographic evidence clearly qualifies phase I dolomite as radiaxial fibrous. Conversely, fascicular optical fabrics were not found. Carbon-isotope ratios (δ13C) are depleted (between - 11.8 and - 22.1‰) as expected for carbonate precipitation from marine pore-fluids in organic-matter-rich, paralic sediment. Oxygen isotope (δ18O) ratios range between - 1.3 and - 6.0‰. The earliest diagenetic nature of these cements is documented by the presence of ubiquitous, non-compacted fossil plant remains encased in phase I dolomite as well as by the complex zoned luminescence patterns in the crystals and is supported by crystallographic and thermodynamic considerations. It is argued that organic matter, and specifically carboxyl groups, reduced thermodynamic barriers for dolomite formation and facilitated Mg/CaCO3 precipitation. The data shown here

LIME REQUIREMENT DETERMINATION AND LIMING IMPACT ON SOIL NUTRIENT STATUS

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Krunoslav Karalić

2010-06-01

Full Text Available The aim of conducted research was to determine the influence of liming, mineral and organic fertilization on soil chemical properties and nutrient availability in the soil, yield height and mineral composition of alfalfa. Results were used to create regression models for prediction of liming impact on soil chemical properties. Liming and fertilization experiment was sat up in 20 L volume plastic pots with two types of acid soils with different texture from two sites. Ten liming and fertilization treatments were applied in four repetitions. Lime treatments increased soil pH values and decreased hydrolytic acidity. Mineral and organic fertilization affected additional soil acidification. Application of lime intensified mineralization and humus decomposition, while organic fertilization raised humus content. The results showed significant increase of AL-P2O5 and K2O availability. The treatments increased soil Ca concentrations, but at the same time decreased exchangeable Mg concentrations. Soil pH increase resulted in lower Fe, Mn, Zn and Cu availability. Soil CEC was increased by applied treatments. Lime rates increased number and height of alfalfa plants, as well as yield of leaf, stalk increased concentrations of N, P, K and Ca in alfalfa leaf and stalk, but decreased leaf Mg and Fe, Mn, Zn and Cu concentrations. Regression computer models predicted with adequate accuracy P, Fe, Mn, Zn and Cu availability and final pH value as a result of liming and fertilization impact.

PCM-enhanced lime plasters for vernacular and contemporary architecture

Science.gov (United States)

Theodoridou, Magdalini; Kyriakou, Loucas; Ioannou, Ioannis

2016-04-01

In 1997, the European Union (EU) pledged to reduce the amount of greenhouse gas emissions by 20% below the levels of 1990 by the end of 2020. In recent years it has become evident that, in order to reach that goal, EU Member States must take measures to encourage sustainability in the building industry, which is a major energy consumer. Such measures should involve the use of innovative, environmentally friendly materials and methods in new constructions, as well as the renovation of existing properties by upgrading their current state of energy efficiency. Phase Change Materials (PCMs) have the ability to absorb and release thermal energy, in the form of latent heat, during the melting or solidifying processes respectively. Thus, they may be used as additives in the production of thermally efficient composite building materials. A PCM-enhanced plaster is a heat storage medium combining an appropriate PCM with a cementitious or non-cementitious matrix to produce a low-cost thermal storage material with structural and thermostatic properties. Although innovative technologies, such as PCMs, have certainly contributed to the boost in the evolution of the building materials industry in recent years, a significant proportion of these technologies and practices have not yet been fully exploited in materials based on traditional principles. This paper focuses on the design and production of novel cementless PCM-enhanced lime plasters, in line with the traditional production technology of lime composites. The new plasters are produced using either hydrated or natural hydraulic lime binder, crushed calcarenite sand (0-2 mm) and commercial microencapsulated PCM in powder form (5% w/w of solids). Results from comparative tests between reference mixtures and mixtures with the addition of PCM, carried out 28, 56 and 90 days after laboratory production, prove the potential of PCMs in enhancing the thermal performance of traditional lime-based composites. The modified composites

Wastewater Sludge Stabilization Using Lime A Case Study of West Ahwaz Wastewater Treatment Plant

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Mehdi Farzadkia

2009-01-01

Full Text Available Lime stabilization is a chemical method used for wastewater sludge stabilization. It is capable of decreasing large quantities of pathogens and of preventing microbial degradation of sludge organic materials. The main objective of the present experimental research was to investigate stabilization of the sludge from west Ahwaz wastewater treatment plant by lime addition and to control if the microbial quality of this sludge conforms to the USEPA standards for sludge reuse and safe disposal. The study was carried out on a pilot scale in 5 stages over a period of 12 months (July 2005 to June 2006 at west Ahwaz wastewater treatment plant laboratory using raw sludge. For the purposes of this study, a 30-liter reactor was commissioned and loaded with sludge and appropriate quantities of hydrated lime were added based on the solid waste percent. The parameters used to determine stabilization efficiency were pH, Total Coliform, Fecal Coliform, and parasite eggs. The results showed that lime addition at a ratio of 265g Ca(OH2/kg. ds was the optimum level for sludge stabilization in westAhwazwastewater treatment plant, which is acceptable from both economic and technical viewpoints. The method is capable of achieving class B but never satisfied class A of USEPA standards.

Phosphorus availability in oxidic soils treated with lime and silicate applications

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Aline da Silva Sandim

2014-08-01

Full Text Available Based on the assumption that silicate application can raise soil P availability for crops, the aim of this research was to compare the effect of silicate application on soil P desorption with that of liming, in evaluations based on two extractors and plant growth. The experiment was carried out in randomized blocks with four replications, in a 3 × 3 × 5 factorial design, in which three soil types, three P rates, and four soil acidity correctives were evaluated in 180 experimental plots. Trials were performed in a greenhouse using corn plants in 20-dm³ pots. Three P rates (0, 50 and 150 mg dm-3 were applied in the form of powder triple superphosphate and the soil was incubated for 90 days. After this period, soil samples were collected for routine chemical analysis and P content determination by the extraction methods resin, Mehlich-1 and remaining P. Based on the results, acidity correctives were applied at rates calculated for base saturation increased to 70 %, with subsequent incubation for 60 more days, when P content was determined again. The acidity correctives consisted of: dolomitic lime, steelmaking slag, ladle furnace slag, and wollastonite. Therefore, our results showed that slags raised the soil P content more than lime, suggesting a positive correlation between P and Si in soil. Silicon did not affect the extractor choice since both Mehlich-1 and resin had the same behavior regarding extracted P when silicon was applied to the soil. For all evaluated plant parameters, there was significant interaction between P rates and correctives; highest values were obtained with silicate.

Lime-water consolidation effects on poor lime mortars

Czech Academy of Sciences Publication Activity Database

Drdácký, Miloš; Slížková, Zuzana

2012-01-01

Roč. 43, č. 1 (2012), s. 31-36 ISSN 0044-9466 R&D Projects: GA ČR(CZ) GA103/09/2067 Institutional support: RVO:68378297 Keywords : lime mortar s * lime -water consolidation * conservation Subject RIV: JN - Civil Engineering

Lime

Science.gov (United States)

Miller, M.

2006-01-01

In 2005, US lime production was 20 Mt with a value of $1.5 billion. Production was unchanged compared with 2004. Captive production was 1.4 Mt. US consumption was 20.2 Mt. Most of the US lime trade was with Canada and Mexico. Despite some disruptions due to hurricanes Katrina and Rita, normal sales activities remained healthy.

Review of Dolomite as Precursor of Geopolymer Materials

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Azimi E.A.

2016-01-01

Full Text Available Geopolymer is an environmentally friendly cementitious binder that does not require the existence of ordinary Portland cement (OPC. Geopolymer has many excellent advantages, including high early strength, low shrinkage, good thermal resistance and good chemical resistance. Previous commonly used materials include fly ash, clay and slag. The used of dolomite as precursor material in geopolymer field is still new and at the early stage of study. Only a few researchers have done studies on dolomite in geopolymer. Dolomite (CaMg(CO32 is abundant and generally inexpensive natural minerals. The possible use of these bulk calcium carbonate materials in improving the mechanical properties of geopolymers will therefore be of great interest. This paper summarizes some research outcomes on dolomite in geopolymer along with the potential of dolomite as geopolymer composites.

Influence of chemical and physical characteristics of cement kiln dusts (CKDs) on their hydration behavior and potential suitability for soil stabilization

International Nuclear Information System (INIS)

Peethamparan, Sulapha; Olek, Jan; Lovell, Janet

2008-01-01

The interaction of CKDs with a given soil depends on the chemical and physical characteristics of the CKDs. Hence, the characterization of CKDs and their hydration products may lead to better understanding of their suitability as soil stabilizers. In the present article, four different CKD powders are characterized and their hydration products are evaluated. A detailed chemical (X-ray diffraction), thermogravimetric and morphological (scanning electron microscope) analyses of both the CKD powders and the hydrated CKD pastes are presented. In general, high free-lime content (∼ 14-29%) CKDs, when reacted with water produced significant amounts of calcium hydroxide, ettringite and syngenite. These CKDs also developed higher unconfined compressive strength and higher temperature of hydration compared to CKDs with lower amounts of free-lime. An attempt was made to qualitatively correlate the performance of CKD pastes with the chemical and physical characteristics of the original CKD powders and to determine their potential suitability as soil stabilizers. To that effect a limited unconfined compressive strength testing of CKD-treated kaolinite clays was performed. The results of this study suggest that both the compressive strength and the temperature of hydration of the CKD paste can give early indications of the suitability of particular CKD for soil stabilization

Effect of liming on nickel bioavailability and toxicity to oat and soybean grown in field soils containing aged emissions from a nickel refinery.

Science.gov (United States)

Cioccio, Stephen; Gopalapillai, Yamini; Dan, Tereza; Hale, Beverley

2017-04-01

Remediation of soils elevated in trace metals so that the soils may provide ecosystems services is typically achieved through pH adjustment or addition of sorbents. The present study aimed to generate higher-tier in situ toxicity data for elevated nickel (Ni) in soils with and without lime addition and to explore the effect of liming on soil chemistry and bioavailability of Ni to plants. A multiyear study of agronomic yield of field-grown oat and soybean occurred in 3 adjacent fields that had received air emissions from a Ni refinery for 66 yr. The soil Ni concentration in the plots ranged between 1300 mg/kg and 4900 mg/kg, and each field was amended with either 50 Mg/ha, 10 Mg/ha, or 0 Mg/ha (or tonnes/ha) of crushed dolomitic limestone. As expected, liming raised the pH of the soils and subsequently reduced the plant availability of Ni. Toxicity thresholds (effective concentrations causing 50% reduction in growth) for limed soils supported the hypothesis that liming reduces toxicity. Relationships were found between relative yield and soil cation exchange capacity and between relative yield and soil pH, corroborating findings of the European Union Risk Assessments and the Metals in Asia studies, respectively. Higher tier ecotoxicity data such as these are a valuable contribution to risk assessment for Ni in soils. Environ Toxicol Chem 2017;36:1110-1119. © 2016 SETAC. © 2016 SETAC.

Nanometer-scale features in dolomite from Pennsylvanian rocks, Paradox Basin, Utah

Science.gov (United States)

Gournay, Jonas P.; Kirkland, Brenda L.; Folk, Robert L.; Lynch, F. Leo

1999-07-01

Scanning electron microscopy reveals an association between early dolomite in the Pennsylvanian Desert Creek (Paradox Fm.) and small (approximately 0.1 μm) nanometer-scale textures, termed `nannobacteria'. Three diagenetically distinct dolomites are present: early dolomite, limpid dolomite, and baroque dolomite. In this study, only the early dolomite contained nanometer-scale features. These textures occur as discrete balls and rods, clumps of balls, and chains of balls. Precipitation experiments demonstrate that these textures may be the result of precipitation in an organic-rich micro-environment. The presence of these nanometer-scale textures in Pennsylvanian rocks suggests that these early dolomites precipitated in organic-rich, bacterial environments.

The antifungal efficiency of carbide lime slurry compared with the commercial lime efficiency

Science.gov (United States)

Strigac, J.; Mikusinec, J.; Strigacova, J.; Stevulova, N.

2017-10-01

The article deals with studying the antifungal efficiency of carbide lime slurry compared to industrially manufactured commercial lime. Antifungal efficiency expressed as mould proofness properties was tested on the fungi using the procedure given in standard CSN 72 4310. A mixture of fungi Aspergillus niger, Chaetomium globosum, Penicillium funiculosum, Paecilomyces variotii and Gliocladium virens was utilized for testing. The scale for evaluating mould proofness properties according to CSN 72 4310 is from 0 to 5 in degree of fungi growth, where 0 means that no fungi growth occurs and the building products and materials possess fungistatic properties. The study confirms the fungistatic propeties of carbide lime slurry as well as industrially manufactured commercial lime. However, carbide lime slurry and industrially manufactured commercial lime possess no fungicidal effect.

The magnesium isotope (δ26Mg) signature of dolomites

Science.gov (United States)

Geske, A.; Goldstein, R. H.; Mavromatis, V.; Richter, D. K.; Buhl, D.; Kluge, T.; John, C. M.; Immenhauser, A.

2015-01-01

Dolomite precipitation models and kinetics are debated and complicated due to the complex and temporally fluctuating fluid chemistry and different diagenetic environments. Using well-established isotope systems (δ18O, δ13C, 87Sr/86Sr), fluid inclusions and elemental data, as well as a detailed sedimentological and petrographic data set, we established the precipitation environment and subsequent diagenetic pathways of a series of Proterozoic to Pleistocene syn-depositional marine evaporative (sabkha) dolomites, syn-depositional non-marine evaporative (lacustrine and palustrine) dolomites, altered marine ("mixing zone") dolomites and late diagenetic hydrothermal dolomites. These data form the prerequisite for a systematic investigation of dolomite magnesium isotope ratios (δ26Mgdol). Dolomite δ26Mg ratios documented here range, from -2.49‰ to -0.45‰ (δ26Mgmean = -1.75 ± 1.08‰, n = 42). The isotopically most depleted end member is represented by earliest diagenetic marine evaporative sabkha dolomites (-2.11 ± 0.54‰ 2σ, n = 14). In comparing ancient compositions to modern ones, some of the variation is probably due to alteration. Altered marine (-1.41 ± 0.64‰ 2σ, n = 4), and earliest diagenetic lacustrine and palustrine dolomites (-1.25 ± 0.86‰ 2σ, n = 14) are less negative than sabkha dolomites but not distinct in composition. Various hydrothermal dolomites are characterized by a comparatively wide range of δ26Mg ratios, with values of -1.44 ± 1.33‰ (2σ, n = 10). By using fluid inclusion data and clumped isotope thermometry (Δ47) to represent temperature of precipitation for hydrothermal dolomites, there is no correlation between fluid temperature (∼100 to 180 °C) and dolomite Mg isotope signature (R2 = 0.14); nor is there a correlation between δ26Mgdol and δ18Odol. Magnesium-isotope values of different dolomite types are affected by a complex array of different Mg sources and sinks, dissolution/precipitation and non

[Review of lime carbon sink.

Science.gov (United States)

Liu, Li Li; Ling, Jiang Hua; Tie, Li; Wang, Jiao Yue; Bing, Long Fei; Xi, Feng Ming

2018-01-01

Under the background of "missing carbon sink" mystery and carbon capture and storage (CCS) technology development, this paper summarized the lime material flow process carbon sink from the lime carbonation principles, impact factors, and lime utilization categories in chemical industry, metallurgy industry, construction industry, and lime kiln ash treatment. The results showed that the lime carbonation rate coefficients were mainly impacted by materials and ambient conditions; the lime carbon sink was mainly in chemical, metallurgy, and construction industries; and current researches focused on the mechanisms and impact factors for carbonation, but their carbon sequestration calculation methods had not been proposed. Therefore, future research should focus on following aspects: to establish a complete system of lime carbon sequestration accounting method in view of material flow; to calculate lime carbon sequestration in both China and the world and explain their offset proportion of CO 2 emission from lime industrial process; to analyze the contribution of lime carbon sequestration to missing carbon sink for clarifying part of missing carbon sinks; to promote the development of carbon capture and storage technology and provide some scientific bases for China's international negotiations on climate change.

Ferroan Dolomitization by Seawater Interaction with Mafic Igneous Dikes and Carbonate Host Rock at the Latemar Platform, Dolomites, Italy: Numerical Modeling of Spatial, Temporal, and Temperature Data

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K. Blomme

2017-01-01

Full Text Available Numerous publications address the petrogenesis of the partially dolomitized Latemar carbonate platform, Italy. A common factor is interpretation of geochemical data in terms of heating via regional igneous activity that provided kinetically favorable conditions for replacement dolomitization. New field, petrographic, XRD, and geochemical data demonstrate a spatial, temporal, and geochemical link between replacement dolomite and local mafic igneous dikes that pervasively intrude the platform. Dikes are dominated by strongly altered plagioclase and clinopyroxene. Significantly, where ferroan dolomite is present, it borders dikes. We hypothesize that seawater interacted with mafic minerals, causing Fe enrichment in the fluid that subsequently participated in dolomitization. This hypothesis was tested numerically through thermodynamic (MELTS, Arxim-GEM and reactive flow (Arxim-LMA simulations. Results confirm that seawater becomes Fe-enriched during interaction with clinopyroxene (diopside-hedenbergite and plagioclase (anorthite-albite-orthoclase solid solutions. Reaction of modified seawater with limestone causes ferroan and nonferroan replacement dolomitization. Dolomite quantities are strongly influenced by temperature. At 40 to 80°C, ferroan dolomite proportions decrease with increasing temperature, indicating that Latemar dolomitization likely occurred at lower temperatures. This relationship between igneous dikes and dolomitization may have general significance due to the widespread association of carbonates with rifting-related igneous environments.

Thorough investigation of the oxygen heterocyclic fraction of lime (Citrus aurantifolia (Christm.) Swingle) juice.

Science.gov (United States)

Costa, Rosaria; Russo, Marina; De Grazia, Selenia; Grasso, Elisa; Dugo, Paola; Mondello, Luigi

2014-04-01

Reversed-phase-HPLC analysis by means of superficially porous silica particle columns (fused-core) was applied to the investigation of flavonoids, coumarins, and psoralens in lime juice samples. Hesperidin (367.0 ± 16.0 ppm) and eriocitrin (148.0 ± 7.9 ppm) were the most abundant flavonoids. Fifteen coumarins and furocoumarins were determined, including bergamottin (29.6 ± 1.1 ppm), 5-geranyloxy-7-methoxycoumarin (16.5 ± 0.6 ppm), and oxypeucedanin hydrate (9.9 ± 0.5 ppm) as predominant compounds. These molecules are today well known for their beneficial effects on human health. As a consequence, the present study, beyond investigating for the first time the chemical composition of lime juice, highlights also its health-promoting qualities, due to its content of flavonoids and coumarins. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Improved Clearing and Mounting Solution to Replace Chloral Hydrate in Microscopic Applications

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Thomas S. Villani

2013-05-01

Full Text Available Premise of the study: This study presents Visikol™, a new proprietary formulation that can be used as an efficient replacement for chloral hydrate as a clearing agent for microscopic examination. In the United States, chloral hydrate is regulated and therefore difficult to acquire. Methods and Results: Fresh and dry samples of the following plants: ginger (Zingiber officinale, maté (Ilex paraguariensis, lime basil (Ocimum americanum, oregano (Origanum vulgare, and mouse-ear cress (Arabidopsis thaliana, were cleared using Visikol or chloral hydrate solution and compared using a light microscope. Conclusions: This new method can be used successfully to clear specimens, allowing identification of diagnostic characteristics for the identification of plant materials. Visikol is as effective as chloral hydrate in providing clarity and resolution of all tissues examined. Tissues become transparent, allowing observation of deeper layers of cells and making it effective in research, botanical and quality control, and for educational applications.

Recovery of drinking water and valuable minerals from acid mine drainage using an integration of magnesite, lime, soda ash, CO(sub)2 and reverse osmosis treatment processes

CSIR Research Space (South Africa)

Masindi, Vhahangwele

2017-08-01

Full Text Available that drinking water, metals, gypsum, hydrated lime/limestone were recovered from the treatment process as valuable resources. This was confirmed by X-ray diffraction (XRD) and X-ray Fluorescence (XRF). Morphological properties of initial and recovered minerals...

Identification of Oxide Compound in Dolomite Mineral from Aceh Tamiang Region

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Nirmala Sari

2013-08-01

Full Text Available Indonesia has abundant mineral especially carbonate-based mineral, ike dolomite. Particularly in Aceh province's, the largest dolomite deposits is available in Aceh Tamiang district around 1.9 billion tons. Unfortunately, current use of dolomite in the industry and other applications is still limited. In this work we report the advanced preparation of dolomite using calcinations method. Whereas, with this method, the dolomite mineral can be processed into calcium and magnesium oxide which has a very wide field of application and higher values. To obtain optimal results, we also identify the effect of temperature on the formation of oxide compounds. Preliminary study using XRF founded that dolomite in village Selamat is known as the highest concentration of CaO (61.20% followed by MgO (25.28%. It is also showed that the main phase obtained by XRD is dolomite (CaMg(CO32. Furthermore, after the calcinations process at 700 °C, it was founded that the formation of dolomite were CaCO3 and MgO, whereas at temperatures of 900 °C mostly the CaCO3 has decomposed into CaO. SEM observations showed that dolomite has the composition of particles distributed homogeneously along the particle agglomerate when it calcinations.

Effect of the Fineness of Artificial Pozzolana (Sarooj on the Properties of Lime-Pozzolana Mixes

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Abdel Wahid Hago

2002-06-01

Full Text Available Strength development of lime-pozzolana mortars is affected by the fineness of the pozzolan. This paper examines the effect of the fineness of artificial pozzolana on the strength development of lime-pozzolana mixtures. An artificial pozzolana produced by calcining clays from Oman was used in this study. The artificial pozzolana is locally known as “Sarooj”, and is currently being used in a big project for the restoration of historical monuments undertaken by the Omani Ministry of National Heritage and Culture. The artificial pozzolana was ground to various degrees of fineness, blended with hydrated lime with a ratio of 3:1, and the resulting mortar was used to make hardened mortar cubes. Strength of mortar cubes was measured at ages of 7, 14, 28 and 90 days of casting. The experimental results show that good artificial pozzolanas show a linear correlation between the Blaine fineness of the artificial pozzolana and the compressive strength, but such relationship does not exists for weak type pozzolanas. The fineness of the artificial pozzolana has its most significant effect on delayed strength gain, with more pronounced effect for good type pozzolan.

The leaching of trifloxysulfuron-sodium and pyrithiobac-sodium in soil columns as a function of soil liming - doi: 10.4025/actasciagron.v35i2.16349

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Naiara Guerra

2012-12-01

Full Text Available Scarce research has been published concerning the effect of soil pH on the leaching potential of herbicides in tropical soils. Thus, we designed this study to evaluate the influence of soil liming on the leaching of trifloxysulfuron-sodium and pyrithiobac-sodium after simulated rainfall depths in soil columns. In the study, two trials were conducted simultaneously; the first experiment evaluated trifloxysulfuron-sodium (7.5 g ha-1, while the second experiment evaluated pyrithiobac-sodium (70 g ha-1. Both experiments were conducted in a randomized block design with a 2 x 4 x 5 factorial scheme and four replications. The design’s factors corresponded to 2 soil liming conditions (with or without liming, 4 simulated rainfall depths (0, 15, 30, and 45 mm and 5 depths in the soil column (0-5, 5-10, 10-15, 15-20, and 20-25 cm. The trials were repeated, and only the source for the soil neutralization was changed, i.e., dolomitic limestone in Experiment 1 and calcium oxide in Experiment 2. Compared to trifloxysulfuron-sodium, the herbicide pyrithiobac-sodium indicated a greater potential for leaching. With more acidic soils, the leaching potential in limed soils was greater for both herbicides. Only the liming that used calcium oxide provided a significant leaching of trifloxysulfuron-sodium for depths greater than 20 cm. Simulated rainfall ≥ 15 mm provided leaching of pyrithiobac-sodium to a depth of 25 cm at near-neutral soil pH values.

Aerobic microbial dolomite at the nanometer scale : Implications for the geologic record

NARCIS (Netherlands)

Sánchez-Román, Mónica; Vasconcelos, Crisógono; Schmid, Thomas; Dittrich, Maria; McKenzie, Judith A.; Zenobi, Renato; Rivadeneyra, Maria A.

2008-01-01

Microbial experiments are the only proven approach to produce experimental dolomite under Earth's surface conditions. Although microbial metabolisms are known to induce dolomite precipitation by favoring dolomite growth kinetics, the involvement of microbes in the dolomite nucleation process is

Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite

Science.gov (United States)

McCormack, J.; Bontognali, T. R. R.; Immenhauser, A.; Kwiecien, O.

2018-04-01

The origin of sedimentary dolomite and the factors that control its formation within the geological record remain speculative. In most models, dolomite formation is linked to evaporative conditions, high water temperature, increasing Mg/Ca ratio, increasing alkalinity, and high amounts of biomass. Here we challenge these archetypal views, by documenting a case example of Quaternary dolomite which formed in Lake Van at constantly low temperature (stress, resulting from reventilation of the water-sediment interface. Independently from the validity of this hypothesis, our results call for a reevaluation of the paleoenvironmental conditions often invoked for early diagenetic dolomite-rich intervals within sedimentary sequences and for caution when interpreting time series of subrecent lacustrine carbonates.

Influence of aluminum hydroxide and lime on the hydration of tricalcium silicate

NARCIS (Netherlands)

de Jong, J.G.M.; Stein, H.N.; Stevels, J.M.

1968-01-01

The influence of amorphorous Al(OH)3 on the hydration of 3CaO.SiO2 in portland cement was studied with an isothermal calorimeter. The reaction mechanism was investigated qual. by x-ray diffraction, D.T.A., ir, and electron microscope methods and the course of Ca(OH)2 concn. was followed quant.

High salinity facilitates dolomite precipitation mediated by Haloferax volcanii DS52

Science.gov (United States)

Qiu, Xuan; Wang, Hongmei; Yao, Yanchen; Duan, Yong

2017-08-01

Although most modern dolomites occur in hypersaline environments, the effects of elevated salinity on the microbial mediation of dolomite precipitation have not been fully evaluated. Here we report results of dolomite precipitation in association with a batch culture of Haloferax volcanii DS52, a halophilic archaeon, under various salinities (from 120‰ to 360‰) and the impact of salinity on microbe-mediated dolomite formation. The mineral phases, morphology and atomic arrangement of the precipitates were analyzed by XRD, SEM and TEM, respectively. The amount of amino acids on the archaeal cell surface was quantified by HPLC/MS. The XRD analysis indicated that disordered dolomite formed successfully with the facilitation of cells harvested from cultures with relatively high salinities (200‰ and 280‰) but was not observed in association with cells harvested from cultures with lower salinity (120‰) or the lysates of cells harvested from extremely high salinity (360‰). The TEM analysis demonstrated that the crystals from cultures with a salinity of 200‰ closely matched that of dolomite. Importantly, we found that more carboxyl groups were presented on the cell surface under high salinity conditions to resist the high osmotic pressure, which may result in the subsequent promotion of dolomite formation. Our finding suggests a link between variations in the hydro-chemical conditions and the formation of dolomite via microbial metabolic activity and enhances our understanding about the mechanism of microbially mediated dolomite formation under high salinity conditions.

Lime-based restoration paints: characterization and evaluation of formulations using a native species from the Amazon flora and PVA-based glue as additives

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Mayra Martins Silva

Full Text Available Abstract Based on historic documents, two lime-based paint formulations were produced in laboratory in order to evaluate their basic characteristics as restoration materials for historic buildings with lime-based components. The paints were made basically with hydrated lime, clay, water and linseed (Linum usitatissimum L. oil, and one formulation had PVA (polyvinyl acetate-based glue as fixative, and the other one, Couma guianensis' latex. Each paint component was characterized by XRD and FTIR, and color and specular gloss measurements were performed on both paints. A preliminary assessment of the paints was conducted using the Pipe Method, the salt crystallization test, visual analysis for dustiness, and analysis of microbiological growth. The results showed that the laboratory-produced paints are theoretically and technologically compatible with lime-based coatings, however, their superficial performance can be improved to achieve greater durability. This study also brings to light local materials from the Amazon region that have great potential to be used and recognized as raw materials for paints and which could also be investigated for other uses.

Diagenetic modification of Knox evaporative-dolomite geochemistry by middle Ordovician paleoaquifer/burial fluids

Energy Technology Data Exchange (ETDEWEB)

Montanez, I.P.; Read, J.F.

1986-05-01

Early Ordovician upper Knox cyclic carbonates (100,000-year periods) were deposited on a ramp in a semiarid setting. Inner ramp facies are completely dolomitized, whereas only cycle caps on the outer ramp are dolomite. Laminite caps on leading edges of prograding flats were dolomitized by evaporative, storm-recharged marine waters that precipitated CoCO/sub 3/ and minor amounts of CaSO/sub 4/. Subtidal facies beneath interiors of supratidal flats (up to 200 km wide)were dolomitized by shallow subsurface brines as the flats prograded. Inner ramp areas existed as supretidal flats for as long as 100,000 years, hence only there are sequences completely dolomitized. Tidal-flat dolomites consist of euhedral to subhedral fabric preservation mosaics (crystals 5-50 ..mu..m, and up to 300 ..mu..m in replaced pelletal layers). Dolomitized subtidal sediments are composed of 20-200 ..mu..m dolomite crystals. Most of the early dolomites are fabric retentive initially, becoming more fabric destructive with increasing exposure to dolomitizing fluids. Fe values are up to 2000 ppm, and Mn values are up to 500 ppm. delta/sup 18/O values show strong geographic control, with samples depleted (up to - 7 per thousand) relative to pristine evaporative dolomites derived from concentrated Ordovician seawater. Burial dolomites are enriched in Fe (up to 14,000 ppm) and depleted in delta/sup 18/O, suggesting precipitation from basinal brines at elevated temperatures. Geochemical data suggest that evaporative dolomites have undergone modification by isotopically lighter fluids. Alteration most likely occurred within a Middle Ordovician meteoric aquifer system or less likely by later Paleozoic basinal brines. Regional geologic data for Knox Group carbonates throughout the eastern US are vital in constraining dolomitization models.

Geochemistry and origin of regional dolomites

International Nuclear Information System (INIS)

Hanson, G.N.; Meyers, W.J.

1989-12-01

The major goal of the carbonate research program at Stony Brook is to better understand the conditions and processes leading to regional diagenesis of carbonate rocks. Our research focuses on studies of ancient, massive dolostones, but we are also studying limestone diagenesis for its own importance, and as it relates to dolomitization. Our approach has been to carry out a very detailed petrographic and geochemical case study to the Mississippian Burlington-Keokuk Fms. of Iowa, Illinois and Missouri, and to develop this as a testing ground for new geochemical and modelling techniques, and for testing various models for regional dolomitization in epicontinental carbonates. The ideas and techniques developed in our Burlington-Keokuk studies are being expanded and applied to carbonate sequences of other ages (Devonian to Neogene), and other tectono-sedimentary settings. The emphasis of this report will be on new developments and results on the Burlington-Keokuk studies and on our diagenetic studies of other strata. Recent research on Burlington-Keokuk rocks include development and application of boron isotopes and the U--Th--Pb system to dolomite studies, investigations of porosity and permeability in the dolostones. Projects on other strata include dolomitization and limestones diagenesis of Devonian carbonates of Alberta and Western Australia, Miocene reefal carbonates of Spain, Neogene carbonates of Curacao and Bonaire, Waulsortian limestones of Ireland, modelling of trace elements and stable isotopes, and experimental growth of calcites to investigate crystallographic controls of trace element incorporation. 118 refs., 46 figs

Hydrothermal dolomite reservoir facies in the Sinian Dengying Fm, central Sichuan Basin

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Yuqiang Jiang

2017-07-01

Full Text Available The Upper Sinian Dengying Fm is the focus of natural gas exploration in the central part of the Sichuan Basin (central Sichuan Basin in recent years. Especially, epigenic karstification and its resulted reservoir-seepage spaces have always been the focal points in researches. Based on the petrographic characteristics of drilling cuttings and core samples, and through experimental analysis by using trace elements, isotopes, and cathodoluminescence, the Dengying Fm dolomite was demonstrated to have matrix recrystallized dolomite (MRD, filled saddle dolomite (FSD (the mean homogenization temperature of inclusion: 178.5 °C, high concentrations of Fe & Mn, slightly positive 87Sr/86Sr value and hydrothermal minerals combination (including sphalerite, galena, pyrite, and quartz, etc.. Thus, it was proposed that hydrothermal dolomite reservoir facies (HDRF exist in the Dengying Fm dolomite, in other words, the dolomite reservoir is composed of hydrothermal dissolved pores, intercrystalline pores of hydrothermal origin, hydrothermal caverns and expanded fractures, and was formed due to the reworking of hydrothermal fluid on tight matrix dolomite. Identification marks are presented in terms of petrography and geochemistry so that hydrothermal dolomite reservoir facies can be effectively recognized and identified. It is concluded that the development of hydrothermal dolomite reservoir facies in this area are preliminary controlled by deep and large basement faults and the strength of hydrothermal fluids.

Influence of deformation on dolomite rim growth kinetics

Science.gov (United States)

Helpa, Vanessa; Rybacki, Erik; Grafulha Morales, Luiz Fernando; Dresen, Georg

2015-04-01

Using a gas-deformation apparatus stacks of oriented calcite (CaCO3) and magnesite (MgCO3) single crystals were deformed at T = 750° C and P = 400 MPa to examine the influence of stress and strain on magnesio-calcite and dolomite (CaMg[CO3]2) growth kinetics. Triaxial compression and torsion tests performed at constant stresses between 7 and 38 MPa and test durations between 4 and 171 hours resulted in bulk strains of 0.03-0.2 and maximum shear strains of 0.8-5.6, respectively. The reaction rims consist of fine-grained (2-7 μm) dolomite with palisade-shaped grains growing into magnesite reactants and equiaxed granular dolomite grains next to calcite. In between dolomite and pure calcite, magnesio-calcite grains evolved with an average grain size of 20-40 μm. Grain boundaries tend to be straighter at high bulk strains and equilibrium angles at grain triple junctions are common within the magnesio-calcite layer. Transmission electron microscopy shows almost dislocation free palisades and increasing dislocation density within granular dolomite towards the magnesio-calcite boundary. Within magnesio-calcite grains, dislocations are concentrated at grain boundaries. Variation of time at fixed stress (˜17 MPa) yields a parabolic time dependence of dolomite rim width, indicating diffusion-controlled growth, similar to isostatic rim growth behavior. In contrast, the magnesio-calcite layer growth is enhanced compared to isostatic conditions. Triaxial compression at given time shows no significant change of dolomite rim thickness (11±2 μm) and width of magnesio-calcite layers (33±5 μm) with increasing stress. In torsion experiments, reaction layer thickness and grain size decrease from the center (low stress/strain) to the edge (high strain/stress) of samples. Chemical analysis shows nearly stoichiometric composition of dolomite palisades, but enhanced Ca content within granular grains, indicating local disequilibrium with magnesio-calcite, in particular for twisted

Rootstocks for 'Tahiti' lime

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Stenzel Neusa Maria Colauto

2004-01-01

Full Text Available The 'Tahiti' lime (Citrus latifolia Tanaka is an important commercial citrus cultivar in Brazil. 'Rangpur' lime has being used as its main rootstock, but it is susceptible to root rot caused by Phytophthora, reducing tree longevity. An experiment was set up in a randomized block design, with three trees per plot of each rootstock and four replicates, and run for 12 years, aiming to compare the performance of 'IAC-5 Tahiti' lime, budded on 'Rangpur' lime (Citrus limonia Osb.; 'C-13' citrange (Citrus sinensis (L. Osb. × Poncirus trifoliata (L. Raf.; 'African' rough lemon (Citrus jambhiri Lush.; 'Volkamer' lemon (Citrus volkameriana Ten. & Pasq.; trifoliate orange (Poncirus trifoliata (L. Raf.; 'Sunki' mandarin (Citrus sunki Hort. ex Tan. and 'Cleopatra' mandarin (Citrus reshni Hort. ex Tan.. Eleven years after the establishment of the orchard, trees with the greatest canopy development were budded on 'C-13' citrange and 'African' rough lemon, and both differed significantly from trees budded on trifoliate orange, 'Sunki' and 'Cleopatra' mandarins, which presented the smallest canopy development. Trees budded on 'Rangpur' lime and 'C-13' citrange had the highest cumulative yields, and were different from trees budded on trifoliate orange, 'Cleopatra' and 'Sunki' mandarins. There was no rootstock effect on mean fruit weight and on the total soluble solid/acid ratio in the juice. The 'Rangpur' lime and the 'Cleopatra' mandarin rootstocks reduced longevity of plants.

Pore structure and carbonation in blended lime-cement pastes

Directory of Open Access Journals (Sweden)

Álvarez, J. I.

2006-06-01

Full Text Available The present study aims to gain a fuller understandingof the curing process in lime pastes (100, 90, 80, 70,60, 50 and 40% lime blended with cement by analyzingcarbonation in these materials. A hydrated, airslaked lime powder and CEM II A/L 32.5 Portlandcement were used for the blends. These materialswere singled out for research primarily because theymay be used in the restoration of heritage monuments.Variation in weight was used as an indicator for carbonation.A new parameter, A, was found to vary inverselywith the percentage of the cement because of theprevalence of Knudsen diffusion in the paste, in turndue to the characteristics of the pore structure, whichwas studied by mercury intrusion porosimetry (MIP.The hygroscopic study conducted on the different pastesprovided information on water content at a givenhumidity and its location, i.e., adsorbed on the surfaceof the pores or condensed inside them, obstructing thediffusion of CO2. The conclusion drawn from this studyof the curing process was that neither drying nor C3Shydration retarded lime carbonation.En este trabajo se estudia el proceso de carbonatacionen pastas mixtas de cal y cemento (100, 90, 80, 70, 60,50 y 40% de cal con el objeto de obtener un mejorconocimiento del proceso de curado en estos materiales.Para ello se ha empleado una cal aerea hidratada en polvoy un cemento Portland del tipo CEM II A/L 32,5. Enparticular, este estudio investiga estos materiales ya quepueden ser utilizados en la restauracion del PatrimonioCultural. Se ha utilizado la variacion de peso como indicadordel proceso de carbonatacion. Se ha establecidoun nuevo parametro, A, que varia inversamente con elporcentaje de cemento en la pasta, debido al predominiode la difusion de Knudsen como consecuencia de laestructura porosa, que ha sido estudiada por medio deporosimetria de intrusion de mercurio (PIM. El estudiohigroscopico realizado sobre las diversas pastas permiteconocer el contenido en agua a una

Nanotoxicity of dolomite mineral of commercial importance in India.

Science.gov (United States)

Patil, Govil; Khan, Mohd Imran; Akhtar, Mohd Javed; Ashquin, Mohd; Sultana, Sarwat; Ahmad, Iqbal

2011-02-01

The risk of occupational exposure to dolomite, an important mineral exists both in organized as well as unorganized sectors. Toxicological profiles of bulk dolomite are meagerly known in general and its nanotoxicity in particular. Effects of micro- and nano particles on cell viability, LDH leakage and markers of oxidative stress were observed. The study indicated that cytotoxicity of dolomite nanoparticles is significantly higher than the microparticles. The study thus suggests for the prescription of exposure limit for nanodolomite in the best interest of health of workers at risk of exposure under mining, milling and industrial environment.

Improved control of sucrose losses and clarified juice turbidity with lime saccharate in hot lime clarification of sugarcane juice and other comparisons with milk of lime

Science.gov (United States)

A comparative investigation of adding milk of lime (MOL) versus lime saccharate (SACCH) in hot lime clarification of juice at a U.S. sugarcane factory was undertaken to quantify performance across the 2009 processing season after a preliminary factory study in 2008. SACCH was prepared by adding hyd...

Can liming change root anatomy, biomass allocation and trace element distribution among plant parts of Salix × smithiana in trace element-polluted soils?

Science.gov (United States)

Vondráčková, Stanislava; Tlustoš, Pavel; Száková, Jiřina

2017-08-01

Willows (Salix spp.) are considered to be effective for the phytoremediation of trace elements from contaminated soils, but their efficiency is limited in heavily polluted soils because of poor growth. Liming can be a desirable measure to decrease the plant availability of elements, resulting in improved plant development. Notably, large root area and maximum soil penetration are basic parameters that improve the efficiency of phytoremediation. The impact of soil chemical properties on willow root anatomy and the distribution of trace elements below-ground have rarely been studied. The effect of liming on root parameters, biomass allocation and trace element distribution in non-harvestable (coarse roots, fine roots, stumps) and harvestable plant parts (twigs and leaves) of Salix × smithiana was assessed at the end of a 4-year pot experiment with two trace element-polluted soils that differed in terms of soil pH. Stump biomass predominated in weakly acidic soil. In neutral soil, the majority of biomass was located in fine roots and stumps; the difference from other plant parts was minor. Trace elements were the most concentrated in fine roots. Translocation to above-ground biomass increased as follows: Pb roots roots). Lime application decreased the concentrations of mobile Cd and Zn and related levels in plants, improved biomass production and root parameters and increased the removal of all trace elements in weakly acidic soil. None or minimum differences in the monitored parameters were recorded for dolomite treatments in both soils. The dose and source of liming had crucial effects on root anatomy. Growing willows in limed trace element-polluted soils is a suitable measure for combination of two remediation strategies, i.e. phytoextraction of Cd and Zn and assisted phytostabilization of As and Pb.

Can Mn–S redox cycling drive sedimentary dolomite formation? A hypothesis

Energy Technology Data Exchange (ETDEWEB)

Petrash, Daniel A.; Lalonde, Stefan V.; González-Arismendi, Gabriela; Gordon, Robert A.; Méndez, José A.; Gingras, Murray K.; Konhauser, Kurt O. (CLS); (UCV-Venezuela); (CNRS-UMR); (Alberta)

2016-06-10

The formation of dolomite in modern peritidal environments is linked to the degradation of buried microbial mats, with complexation of Ca and Mg by extracellular polymeric substances (EPSs) and alkalinity generation through organic carbon respiration facilitating the nucleation of dolomite precursors. In the past two decades, microbial sulfate reduction, methanogenesis, and methanotrophy have all been considered as potential drivers of the nucleation process, but it remains unclear why dolomite formation could not also occur in suboxic sediments where abundant alkalinity is produced by processes linked to Mn(IV) and/or Fe(III) reduction coupled with the diffusion and reoxidation of reduced sulfur species. Here we report the interstitial occurrence of spheroidal aggregates of nanometer-scale Ca-rich dolomite rhombohedra within suboxic sediments associated with remnant microbial mats that developed in the peritidal zone of the Archipelago Los Roques, Venezuela. Multiple analytical tools, including EPMA, ICP-MS, synchrotron-based XRF and XRD, and spatially resolved XANES microanalyses, show that the dolomite-cemented interval exhibits depleted bulk iron concentrations, but is interstitially enriched in Mn and elemental sulfur (S⁰). Manganese occurs in several oxidation states, indicating that the dolomite-cemented interval was the locus of complex biological redox transformations characterized by coupled Mn and S cycling. The tight correspondence between sedimentary Mn and MgCO₃ concentrations further hints at a direct role for Mn during dolomitization. While additional studies are required to confirm its relevance in natural settings, we propose a model by which coupled Mn–S redox cycling may promote alkalinity generation and thus dolomite formation in manner similar to, or even more efficiently, than bacterial sulfate reduction alone.

First discovery of dolomite and magnesite in living coralline algae and its geobiological implications

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M. C. Nash

2011-11-01

Full Text Available Dolomite is a magnesium-rich carbonate mineral abundant in fossil carbonate reef platforms but surprisingly rare in modern sedimentary environments, a conundrum known as the "Dolomite Problem". Marine sedimentary dolomite has been interpreted to form by an unconfirmed, post-depositional diagenetic process, despite minimal experimental success at replicating this. Here we show that dolomite, accompanied by magnesite, forms within living crustose coralline alga, Hydrolithon onkodes, a prolific global tropical reef species. Chemical micro-analysis of the coralline skeleton reveals that not only are the cell walls calcitised, but that cell spaces are typically filled with magnesite, rimmed by dolomite, or both. Mineralogy was confirmed by X-ray Diffraction. Thus there are at least three mineral phases present (magnesium calcite, dolomite and magnesite rather than one or two (magnesium calcite and brucite as previously thought. Our results are consistent with dolomite occurrences in coralline algae rich environments in fossil reefs of the last 60 million years. We reveal that the standard method of removing organic material prior to Xray Diffraction analysis can result in a decrease in the most obvious dolomite and magnesite diffraction patterns and this may explain why the abundant protodolomite and magnesite discovered in this study has not previously been recognized. This discovery of dolomite in living coralline algae extends the range of palaeo-environments for which biologically initiated dolomite can be considered a possible source of primary dolomite.

Arsenic removal by lime softening

DEFF Research Database (Denmark)

Kaosol, T.; Suksaroj, C.; Bregnhøj, Henrik

2002-01-01

This paper focuses on the study of arsenic removal for drinking water by lime softening. The initial arsenic (V) concentration was 500 and 1,000 ug/L in synthetic groundwater. The experiments were performed as batch tests with varying lime dosages and mixing time. For the synthetic groundwater......, arsenic (V) removal increased with increasing lime dosage and mixing time, as well as with the resulting pH. The residual arsenic (V) in all cases was lower than the WHO guideline of 10 ug/L at pH higher than 11.5. Kinetic of arsenic (V) removal can be described by a first-order equation as C1 = C0*e......^-k*t. The relation between the constant (k value) and increasing lime dosage was found to be linear, described by k = 0.0034 (Dlime). The results support a theory from the literature that the arsenic (V) was removed by precipitation af Ca3(AsO4)2. The results obtained in the present study suggest that lime...

The effects of acid irrigation and compensation liming on soil and trees in a mature Norway spruce stand (Hoeglwald project)

International Nuclear Information System (INIS)

Kreutzer, K.; Schierl, R.; Goettlein, A.; Proebstle, P.

1989-01-01

Since 1984 the soil of an around 80 years old spruce stand (Picea abies L. Karst.) was irrigated with acidified water (pH 2.7 - 2.8 by H 2 SO 4 resp. pH 5 - 5.5 by H 2 CO 3 ) in 15 to 18 events a 10 - 12 mm per year additionally to natural rain of 500 to 700 mm below canopy with pH mostly between 4.5 - 5.2. The main part of the added acidity was buffered in the mineral top soil by reactions releasing Al (H 2 O) 6 3+ . A small part was consumed in the surface humus layer by exchange of Ca, Mg, Mn and K. Up to now the trees do not show any signs of growth reductions, needle losses or discolourations. It seems that defensive mechanisms in the fine root system are responsible for that as active raise of pH on the rhizoplane of fine roots, possibly due to nitrate uptake. Liming, carried out once in April 1984 with 4 x 10 3 kg ground dolomite per ha, produced a strong increase of the pH only in the upper part of the humus layer, forming a steep pH gradient by depth. That gradient marking the deacidification front is moving downward very slowly with time (around 1 cm/year). Although nitrification was already very active before lime was brought out liming enhanced the nitrate production markedly. At a depth of 20 cm the nitrate concentrations reached 280 mg/l in the soil solution. Liming also enhanced the release of water soluble humic substances. Because of their ability to form stable metal organic complexes with Fe, Cu, Pb and Al, the contents of these metals increased in the soil solutions. (orig.)

Microbial dolomite crusts from the carbonate platform off western India

Digital Repository Service at National Institute of Oceanography (India)

Rao, V.P.; Kessarkar, P.M.; Krumbein, W.E.; Krajewski, K.P.; Schneider, R.J.

Association of Sedimentologists, Sedimentology, 50, 819-830 Microbial dolomite crusts off western India 821 dolomite crusts [2 x 2·5 em to 3 x 0'5 em) and pebbles occur within these sediments. METHODS Thin sections of the crusts were studied petro graphically....E. (19S7) Holocene dolomitization Df supr

Production of biodiesel from palm oil using modified Malaysian natural dolomites

International Nuclear Information System (INIS)

Shajaratun Nur, Z.A.; Taufiq-Yap, Y.H.; Rabiah Nizah, M.F.; Teo, Siow Hwa; Syazwani, O.N.; Islam, Aminul

2014-01-01

Highlights: • Transesterification was carried out using modified Malaysian natural dolomite catalyst. • Characterizations of the catalyst were performed by using XRD, TPD-CO 2 , BET and SEM. • Maximum biodiesel conversion of 100% was achieved from SnO 2 /dolomite catalyst. • The yield was affected by the surface are as well as the basicity of catalyst. • The transesterification reaction gave significant conversion with relatively lower amount of catalyst. - Abstract: Calcined dolomite (AD), produced by calcination of Malaysian dolomite (UD) promotes a potential natural catalyst for biodiesel production from palm oil with the conversion of 99.98%. The catalysts were characterized by using X-ray Diffractometer (XRD), Brunauer–Emmet–Teller (BET) surface area, Scanning Electron Microscopy (SEM) and Temperature Programmed Desorption (TPD) of CO 2 . All catalysts were then employed for transesterification reaction under different conditions (time, methanol to oil molar ratio and amount of catalyst). SnO 2 doped on activated dolomite (SD) shows an optimum conversion (99.98%) at conditions, i.e. 15:1 methanol to oil molar ratio in 4 h compared to ZnO doped on activated dolomite (ZD) and AD. The catalytic activities of these catalysts were found to be depending on the basicity as well as the surface area of the catalyst used

Research on the removal of radium from uranium effluent by air-aeration hydrated manganese hydroxide adsorption

International Nuclear Information System (INIS)

Zhang Jianguo; Chen Shaoqing; Qi Jing

2002-01-01

In the acidic leaching uranium process, pyrolusite or manganese oxide (MnO 2 ) powder is often used as an oxidizer. In the processed effluent, manganese ion present as a contaminant in addition to U, Ra, Th, As, Zn, Cu, F, SO 4 2- , etc. Manganese ion content is about 100∼200 mg/1 in effluent. In this case, a new process technique can be developed to treat the effluent using the Mn 2+ present in the effluent. The approach is as follows: The effluent is neutralized by lime milk to pH about 11. As a result, most contaminants are precipitated to meet the uranium effluent discharge standards (U, Th, Mn, SO 4 2- etc.), but radium is still present in the effluent. In this process, manganese ion forms manganese hydroxide Mn(OH) 2 . The manganese hydroxide is easily to oxide to form MnO(OH) 2 by air aeration. This hydrated manganese hydroxide complex can then be used to adsorb radium in effluent. The experiments show: (1) Effluent pH, manganese concentration in effluent, and aeration strength and time etc. influence the radium removal efficiency. Under the test conditions, when manganese in effluent is between 100∼300 mg/l, and pH is over 10.5, radium can be reduced to lower 1.11 Bq/1 in the processed effluent. Higher contents of impurity elements such as aluminum, silicon and magnesium in the effluent affect the removal efficiency; (2) Under the experimental conditions, the lime precipitation air-aeration formed hydrated manganese hydroxide complex sludge is stable. There is no obvious release of radium from the adsorbed hydrated manganese hydroxide complex sludge; (3) The current experiments show that hydrated manganese hydroxide complex sludge has a very good re-adsorption ability for removal of radium from uranium effluent. Some experimental parameters have been measured. (author)

Effects of ancient porosity and permeability on formation of sedimentary dolomites: Devonian Jefferson Formation (Frasnian), south-central Montana

Energy Technology Data Exchange (ETDEWEB)

Smith, T.M.; Dorobek, S.L.

1987-08-01

Petrographic and geochemical evidence indicates that multiple dolomitization and dolomite stabilization events affected the Devonian Jefferson Formation (Frasnian) in south-central Montana. Several types of dolomite occur, defined by cathodoluminescence: nonzoned, dully luminescent subhedral-anhedral mosaics (most common), euhedral nonzoned and zoned dolomites, zoned dolomite cements, and irregularly luminescent dolomites (dully luminescent with irregularly luminescent regions). The irregularly luminescent fabrics probably represent partial replacement of early dolomite phases with later dolomite phases. Nonzoned, Ca-enriched, euhedral dolomites occur in calcite-cemented, coarse-grained limestone layers. These permeable layers probably were conduits for early meteoric waters, that occluded porosity in the limestones and prevented later dolomite stabilization. Irregularly luminescent dolomites are interpreted as intermediate fabrics in the dolomite stabilization process. Later calcite cements which occlude intercrystalline porosity prevented further dolomite replacement. Total recrystallization of remaining dolomites and formation of final dully luminescent mosaics occurred prior to brecciation and stylolitization.

A Study on the quantification of hydration and the strength development mechanism of cementitious materials including amorphous phases by using XRD/Rietveld method

International Nuclear Information System (INIS)

Yamada, Kazuo; Hoshino, Seiichi; Hirao, Hiroshi; Yamashita, Hiroki

2008-01-01

X-ray diffraction (XRD)/Rietveld method was applied to measure the phase composition of cement. The quantative analysis concerning the progress of hydration was accomplished in an error of about the maximum 2-3% in spite of including amorphous materials such as blast furnace slag, fly ash, silica fume and C-S-H. The influence of the compressive strength on the lime stone fine powder mixture material was studied from the hydration analysis by Rietveld method. The two stages were observed in the strength development mechanism of cement; the hydration promotion of C 3 S in the early stage and the filling of cavities by carbonate hydrate for the longer term. It is useful to use various mixture materials for the formation of the resource recycling society and the durability improvement of concrete. (author)

Dolomite clumped isotope constraints on the oxygen isotope composition of the Phanerozoic Sea

Science.gov (United States)

Ryb, U.; Eiler, J. M.

2017-12-01

The δ18O value of the Phanerozoic Sea has been debated several decades, largely motivated by an 8‰ increase in δ18O of sedimentary carbonates between the Cambrian and the present. Some previous studies have interpreted this increase to be a primary depositional signal, resulting from an increase in the 18O content of ocean water over time, or from a decrease in ocean temperature increasing the oxygen isotope fractionation between seawater and carbonates. In contrast, other studies have interpreted lower δ18O compositions as the products of diagenetic alteration at elevated burial temperatures. Here, we show that the Phanerozoic dolomite δ18O record overlaps with that of well-preserved calcite fossils, and use carbonate clumped isotope measurements of Cambrian to Pleistocene dolomites to calculate their formation temperatures and the isotopic compositions of their parent-waters. The observed variation in dolomite δ18O is largely explained by dolomite formation at burial temperatures of up to 158°C. The δ18O values of dolomite parent-waters range -2 to +12‰ and are correlated with formation temperatures. Such correlation is consistent with the modification of seawater (0±2‰, VSMOW) toward isotopically heavier compositions through water-rock reactions at elevated burial temperatures. The similarity between the dolomite and calcite δ18O records, and published clumped isotope-based calculations of water compositions, suggests that like dolomite, temporal variations of the calcite δ18O record may also be largely driven by diagenetic alteration. Finally, the relationship we observe between temperature of dolomitization and d18O of dolomite suggests platform carbonates generally undergo dolomitization through reaction with modified marine waters, and that there is no evidence those waters were ever significantly lower in d18O than the modern ocean.

Earth mortars and earth-lime renders

Directory of Open Access Journals (Sweden)

Maria Fernandes

2008-01-01

Full Text Available Earth surface coatings play a decorative architectural role, apart from their function as wall protection. In Portuguese vernacular architecture, earth mortars were usually applied on stone masonry, while earth renders and plasters were used on indoors surface coatings. Limestone exists only in certain areas of the country and consequently lime was not easily available everywhere, especially on granite and schist regions where stone masonry was a current building technique. In the central west coast of Portugal, the lime slaking procedure entailed slaking the quicklime mixed with earth (sandy soil, in a pit; the resulting mixture would then be combined in a mortar or plaster. This was also the procedure for manufactured adobes stabilized with lime. Adobe buildings with earth-lime renderings and plasters were also traditional in the same region, using lime putty and lime wash for final coat and decoration. Classic decoration on earth architecture from the 18th-19th century was in many countries a consequence of the François Cointeraux (1740-1830 manuals - Les Cahiers d'Architecture Rurale" (1793 - a French guide for earth architecture and building construction. This manual arrived to Portugal in the beginning of XIX century, but was never translated to Portuguese. References about decoration for earth houses were explained on this manual, as well as procedures about earth-lime renders and ornamentation of earth walls; in fact, these procedures are exactly the same as the ones used in adobe buildings in this Portuguese region. The specific purpose of the present paper is to show some cases of earth mortars, renders and plasters on stone buildings in Portugal and to explain the methods of producing earth-lime renders, and also to show some examples of rendering and coating with earth-lime in Portuguese adobe vernacular architecture.

Structure and Stability of High-Pressure Dolomite with Implications for the Earth's Deep Carbon Cycle

Science.gov (United States)

Solomatova, N. V.; Asimow, P. D.

2014-12-01

Carbon is subducted into the mantle primarily in the form of metasomatically calcium-enriched basaltic rock, calcified serpentinites and carbonaceous ooze. The fate of these carbonates in subduction zones is not well understood. End-member CaMg(CO3)2 dolomite typically breaks down into two carbonates at 2-7 GPa, which may further decompose to oxides and CO2-bearing fluid. However, high-pressure X-ray diffraction experiments have recently shown that the presence of iron may be sufficient to stabilize dolomite I to high pressures, allowing the transformation to dolomite II at 17 GPa and subsequently to dolomite III at 35 GPa [1][2]. Such phases may be a principal host for deeply subducted carbon. The structure and equation of state of these high-pressure phases is debated and the effect of varying concentrations of iron is unknown, creating a need for theoretical calculations. Here we compare calculated dolomite structures to experimentally observed phases. Using the Vienna ab-initio simulation package (VASP) interfaced with a genetic algorithm that predicts crystal structures (USPEX), a monoclinic phase with space group 5 ("dolomite sg5") was found for pure end-member dolomite. Dolomite sg5 has a lower energy than reported dolomite structures and an equation of state that resembles that of dolomite III. It is possible that dolomite sg5 is not achieved experimentally due to a large energy barrier and a correspondingly large required volume drop, resulting in the transformation to metastable dolomite II. Due to the complex energy landscape for candidate high-pressure dolomite structures, it is likely that several competing polymorphs exist. Determining the behavior of high-pressure Ca-Mg-Fe(-Mn) dolomite phases in subduction environments is critical for our understanding of the Earth's deep carbon cycle and supercell calculations with Fe substitution are in progress. [1] Mao, Z., Armentrout, M., Rainey, E., Manning, C. E., Dera, P., Prakapenka, V. B., and Kavner, A

Ectomycorrhizal activity as affected by soil liming

Energy Technology Data Exchange (ETDEWEB)

Andersson, Solbritt

1996-05-01

Acidification of the forest soils in southern Sweden due to atmospheric deposition has become evident during recent decades. To counteract further acidification, liming of forests in the most affected areas has been proposed. Most forest trees in the temperate and boreal forest ecosystems live in symbiosis with ectomycorrhizal fungi, and their uptake of mineral nutrients from the soil is greatly influenced by the symbiosis. In this thesis effects of liming on ectomycorrhiza have been studied in relation to effects on root colonization, fungal growth and nitrogen uptake. In field experiments the effects of liming on ectomycorrhizal colonization of root tips were variable, possibly due to different soil types and climatic variations. However, a changed mycorrhizal community structure could be detected. Laboratory studies also showed that the substrate may influence the outcome of lime applications; the nutrient status of the substrate had a marked effect on how mycelial growth was affected by liming. Under the experimental conditions used in the studies presented in this thesis, liming reduced the uptake of nitrogen and phosphorus by both mycorrhizal and non-mycorrhizal plants. The amount of extractable nitrogen and phosphorus in the peat was also reduced by liming. The latter could be due to either microbial or chemical immobilization. The lime induced decrease in nitrogen uptake was stronger in non-mycorrhizal plants than in mycorrhizal plants. Thus, the mycorrhizal plants had a higher ability to deal with the negative effects of liming on nitrogen availability. This was not the case for phosphorus. The lime induced decrease in phosphorus uptake was stronger for mycorrhizal plants, and in the highest lime treatment there was no significant difference between the mycorrhizal and the non-mycorrhizal spruce plants. 76 refs, 2 figs, 1 tab

Dolomitization and sedimentary cyclicity of the Ordovician, Silurian, and Devonian rocks in South Estonia

Directory of Open Access Journals (Sweden)

Kallaste, Toivo

2006-03-01

Full Text Available The distribution and composition of dolomitized rocks and stoichiometry of dolomite in southern Estonia in the Ordovician, Silurian, and Devonian were studied on the background of the facies, sedimentary cyclicity (nine shallowing-up cycles, and evolution of the palaeobasins. The composition of rocks and lattice parameters of dolomite were investigated using the X-ray diffraction, X-ray fluorescence, titration and gravimetric analyses, and porosity measurements. The formation of dolostones is directly determined by the cyclic evolution of palaeobasins. Dolomitized rocks belong to the shallow-water inner shelf or tidal/lagoonal facies belt of regressive phases of sedimentary cycles. Sediments of the deep shelf/transitional environment and transgressive phases are not dolomitized. The most stoichiometric is secondary replacive dolomite of Silurian and upper Ordovician dolostones, formed during the early diagenesis of normal-marine (saline shallow-shelf calcitic sediments. The content of insoluble residue does not affect the stoichiometry. The changes in lattice parameters are induced by the Ca/Mg ratio in the dolomite lattice. The dolomite of the dolostones contacting limestone or containing calcite has an expanded lattice. The primary (syngenetic dolostone of the lagoonal or tidal flat belt has also an expanded lattice. No dolomitizing effect of the waters of the Devonian palaeobasin on the underlying rocks was revealed. The whole data set of the studied dolostones is consistent with the marine water environment in the palaeobasin at the corresponding time and shows no sign of the inflow of external fluids. It suggests that the microbial model of dolomite formation may characterize the Ordovician, Silurian, and Devonian in southern Estonia. The occurrence of dolostones between undolomitized rocks limits the time of dolomitization to the early diagenetic stage.

The Stabilization of Weathered Dolerite Aggregates with Cement, Lime, and Lime Fly Ash for Pavement Construction

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Felix N. Okonta

2014-01-01

Full Text Available An experimental program was performed on weathered dolerite specimens stabilized by adding varying percentages of cement (4, 8, 12, and 16 % and lime (6 and 12 % and a combination of lime and fly ash (6% lime + 12% Fly ash and 12% lime + 12% Fly ash % by dry weight of soil. The strength was examined under three different curing methods, namely, membrane curing (MBC, alternate moist-air curing (MAC, and water curing (WAC, by conducting unconfined compressive strength (UCS tests. Simple polynomial and linear functions (regression models were used to define the relationships between the variables investigated. Membrane curing (MBC gave results close enough to the water curing (WAC to indicate that it can be confidently used on the field during pavement construction. From the results obtained, for class B (interurban collector and major rural roads pavement construction, addition of 8% cement was recommended for road base construction with stabilized WDA. Also the addition of 12 + 12% Lime and Fly Ash was recommended for road subbase construction with stabilized WDA. Stabilized WDA against the prejudiced myths would perform satisfactorily for base and subbase construction in both heavily trafficked and low volume roads with economic quantities of cement, lime, and fly ash in South Africa.

Recycled sand in lime-based mortars.

Science.gov (United States)

Stefanidou, M; Anastasiou, E; Georgiadis Filikas, K

2014-12-01

The increasing awareness of the society about safe guarding heritage buildings and at the same time protecting the environment promotes strategies of combining principles of restoration with environmentally friendly materials and techniques. Along these lines, an experimental program was carried out in order to investigate the possibility of producing repair, lime-based mortars used in historic buildings incorporating secondary materials. The alternative material tested was recycled fine aggregates originating from mixed construction and demolition waste. Extensive tests on the raw materials have been performed and mortar mixtures were produced using different binding systems with natural, standard and recycled sand in order to compare their mechanical, physical and microstructure properties. The study reveals the improved behavior of lime mortars, even at early ages, due to the reaction of lime with the Al and Si constituents of the fine recycled sand. The role of the recycled sand was more beneficial in lime mortars rather than the lime-pozzolan or lime-pozzolan-cement mortars as a decrease in their performance was recorded in the latter cases due to the mortars' structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation and Characterization of Malaysian Dolomites as a Tar Cracking Catalyst in Biomass Gasification Process

Directory of Open Access Journals (Sweden)

M. A. A. Mohammed

2013-01-01

Full Text Available Three types of local Malaysian dolomites were characterized to investigate their suitability for use as tar-cracking catalysts in the biomass gasification process. The dolomites were calcined to examine the effect of the calcination process on dolomite’s catalytic activity and properties. The modifications undergone by dolomites consequent to thermal treatment were investigated using various analytical methods. Thermogravimetric and differential thermal analyses indicated that the dolomites underwent two stages of decomposition during the calcination process. The X-ray diffraction and Fourier-transform infrared spectra analyses showed that thermal treatment of dolomite played a significant role in the disappearance of the CaMg(CO32 phase, producing the MgO-CaO form of dolomite. The scanning electron microscopy microphotographs of dolomite indicated that the morphological properties were profoundly affected by the calcination process, which led to the formation of a highly porous surface with small spherical particles. In addition, the calcination of dolomite led to the elimination of carbon dioxide and increases in the values of the specific surface area and average pore diameter, as indicated by surface area analysis. The results showed that calcined Malaysian dolomites have great potential to be applied as tar-cracking catalysts in the biomass gasification process based on their favorable physical properties.

Ab Initio Study of the Structure and Stability of High-Pressure Iron-Bearing Dolomite

Science.gov (United States)

Solomatova, N. V.; Asimow, P. D.

2016-12-01

Carbon is subducted into the mantle primarily in the form of metasomatically calcium-enriched basaltic rock, calcified serpentinites and carbonaceous ooze, all of which often contain dolomite. End-member CaMg(CO3)2 dolomite typically breaks down upon compression into two carbonates at 5-6 GPa in the temperature range of 800-1200 K [1]. However, high-pressure X-ray diffraction experiments have recently shown that the presence of iron may be sufficient to stabilize high-pressure dolomite over single-cation carbonates above 35 GPa [2,3]. The structure and equation of state of high-pressure dolomite phases have been debated, creating a need for theoretical calculations. Using density functional theory interfaced with a genetic algorithm that predicts crystal structures (USPEX), we have found a monoclinic phase with space group C2/c. The C2/c structure has a lower energy than previously reported dolomite structures at relevant pressures. It is possible that this phase is not achieved experimentally due to a large energy barrier and a correspondingly large required volume drop, resulting in the transformation to metastable dolomite II. We calculate the equation of state of trigonal dolomite, dolomite III and monoclinic C2/c dolomite to 80 GPa with 0 and 50 mol% CaFe(CO3)2 and compare their enthalpies to single-carbonate assemblages. Although end-member C2/c CaMg(CO3)2 dolomite is not stable relative to single-cation carbonates, C2/c CaMg0.5Fe0.5(CO3)2 is preferred over single-cation carbonates at high pressures. Thus, iron-bearing C2/c dolomite may be an important host phase for carbon in slabs subducted into the lower mantle. [1] Shirasaka, M., et al. (2002) American Mineralogist, 87, 922-930. [2] Mao, Z. et al. (2011) Geophysical Research Letters, 38. [3] Merlini, M. et al. (2012) Proceedings of the National Academy of Sciences, 109, 13509-13514.

Durability of air lime mortar

DEFF Research Database (Denmark)

Nielsen, Anders

2016-01-01

This contribution deals with the physical and chemical reasons why pure air lime mortars used in masonry of burned bricks exposed to outdoor climate have shown to be durable from the Middle Ages to our days. This sounds strange in modern times where pure air lime mortars are regarded as weak...... materials, which are omitted from standards for new masonry buildings, where use of hydraulic binders is prescribed. The reasons for the durability seam to be two: 1. The old mortars have high lime contents. 2. The carbonation process creates a pore structure with a fine pored outer layer and coarser pores...

Trichloroethylene decomposition and in-situ dry sorption of Cl-products by calcium oxides prepared from hydrated limes.

Science.gov (United States)

Gotoh, Yoshimi; Iwata, Goichi; Choh, Kyaw; Kubota, Mitsuhiro; Matsuda, Hitoki

2011-10-01

A comparison of CaOs produced by calcining two types of hydrated lime and calcium carbonate was made for decomposition of trichloroethylene and in-situ dry sorption of the decomposed Cl-products using a lab-scale gas flow type tubular packed bed reactor. About 20 mg of CaO sample was mixed with about 2 g of Al2O3 particles and packed in the reactor and allowed to react with a flowing standard gas containing 500 ppm of C2HCl3 (N2 balance) at 673 and 873 K, under the condition that the reaction of CaO with C2HCl3 might be completed within a few hours. It was found that no thermal decomposition of C2HCl3 at or below 673 K was observed in a reactor packed only with Al2O3 particles. However, a considerable amount of decomposition of C2HCl3 was obtained in a reactor packed with CaO and Al2O3, even at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 673 K, decomposition of 0.42 mol of C2HCl3 and in-situ absorption product of 0.53 mol of CaCl2 were obtained. At 873 K, about 46% of C2HCl3 was thermally decomposed. The total amount of C2HCl3 decomposed in CaO-Al2O3 particle bed at 873 K became nearly twice larger than that at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 873 K, decomposition of 0.59 mol of C2HCl3 and in-situ absorption product of 0.67 mol of CaCl2 were obtained. Small amounts of C2Cl2, C2Cl4, CCl4, etc. were detected during decomposition of C2HCl3 at 673 and 873 K. It was recognized that the data on decomposition of C2HCl3 as well as in-situ dry sorption of Cl-products in CaO particle bed were correlated with specific surface area of the CaO employed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Modification of Lime Mortars with Synthesized Aluminosilicates

Science.gov (United States)

Loganina, Valentina I.; Sadovnikova, Marija E.; Jezierski, Walery; Małaszkiewicz, Dorota

2017-10-01

The increasing attention for restoration of buildings of historical and architectural importance has increased the interest for lime-based binders, which could be applied for manufacturing repair mortars and plasters compatible with historical heritage. Different additives, admixtures or fibers may be incorporated to improve mechanical and thermal features of such materials. In this study synthesized aluminosilicates (SA) were applied as an additive for lime mortar. The technology of synthesis consisted in the deposition of aluminosilicates from a sodium liquid glass by the aluminum sulphate Al2(SO4)3. The goal of this investigation was developing a new method of aluminosilicates synthesis from a sodium liquid glass and using this new material as a component for a lime mortar. Aluminosilicates were precipitated from the solution of aluminum sulphate Al2(SO)3 and sodium silicate. SA were then used as an additive to calcareous compositions and their influence was tested. Mortars were prepared with commercial air lime and siliceous river sand. Air lime binder was replaced by 5 and 10 wt.% of SA. Calcareous composition specimens were formed at water/lime ratio 1.0. The following analyses were made: grain size distribution of SA, X-ray diffraction analysis (XRD), sorption properties, plastic strength and compressive strength of lime mortars. XRD pattern of the SA shows the presence of thenardite, gibbsite and amorphous phase represented by aggregate of nano-size cristobalite-like crystallites. Application of SA leads to increase of compressive strength after 90 days of hardening by 28% and 53% at SA content 5 and 10% respectively comparing to specimens without this additive. Contents of chemically bound lime in the reference specimens after 28 days of hardening in air-dry conditions was 46.5%, while in specimens modified with SA contained 50.0-55.3% of bound lime depending on filtrate pH. This testifies to high activity of calcareous composition. The new blended lime

27 CFR 9.27 - Lime Kiln Valley.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Lime Kiln Valley. 9.27... OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.27 Lime Kiln Valley. (a) Name. The name of the viticultural area described in this section is “Lime Kiln Valley...

Tectonics of the crystalline Basement of the Dolomites in North Italy

NARCIS (Netherlands)

Agterberg, F.P.

1961-01-01

The present thesis deals with a number of crystalline regions around the Dolomites in North Italy. The geographic position is shown on sheet I, which is depicted in fig. 105. The Dolomites proper consist mainly of Permotriassic, overlying a transgression plane, which cuts off the

Extraction of magnesium from calcined dolomite ore using hydrochloric acid leaching

Science.gov (United States)

Royani, Ahmad; Sulistiyono, Eko; Prasetiyo, Agus Budi; Subagja, Rudi

2018-05-01

Magnesium is widely used in varieties industrial sector. Dolomite is one source of magnesium besides seawater. The extraction of magnesium from dolomite ores can be done by leaching process. In this work, the dolomite leaching to extract magnesium by hydrochloric acid was investigated. The leaching experiments were performed in a spherical glass batch reactor having a capacity of 1000 ml. The effects of the stirring speed, acid concentration, reaction temperature and liquid-solid ratio for each reaction time of 1; 2; and 3 h on the Mg leaching have been evaluated. 5 ml of solution sample were collected from the leached solutions, then it was filtered prior to analysis by ICP OES. The experimental results show that the magnesium extraction increases along with the increase of acid concentration, liquid-solid ratio and temperature. The optimum conditions for magnesium extraction were achieved at temperature 75 °C, extraction time 3 h, the HCl concentration of 2 M, the liquid-solid ratio 20 ml/g and stirring speed of 400 rpm. At this condition 98, 82 % of magnesium were extracted from dolomite. The conclusion obtained from this leaching process is that the magnesium can be extracted from dolomite by using hydrochloric acid solutions.

DOLOMITE THERMAL-DECOMPOSITION MACROKINETIC MODELS FOR EVALUATION OF THE GASGENERATORS SORBENT SYSTEMS

Directory of Open Access Journals (Sweden)

K. V. Dobrego

2015-01-01

Full Text Available Employing dolomite in the capacity of a sorbent for generator gas purification is of considerable interest nowadays, as it is the impurity of generator gas that causes the major problem for creating cheep and effective co-generator plants. Designing gas purification systems employs simple but physically adequate macrokinetic models of dolomite thermal decomposition.  The  paper  analyzes  peculiarities  of  several  contemporaneous  models  of  dolomite and calcite thermal decomposition and infers on reasonable practicality for creating compact engineering dolomite-decomposition macrokinetic models and universal techniques of these models parameter reconstruction for specific dolomite samples. Such technics can be founded on thermogravimetric data and standard approximation error minimizing algorithms.The author assumes that CO2  evacuation from the reaction zone within the particle may proceed by diffusion mechanism and/or by the Darcy filtration and indicates that functional dependence of the thermal-decomposition rate from the particle sizes and the temperature differs for the specified mechanisms. The paper formulates four macrokinetic models whose correspondence verification is grounded on the experimental data. The author concludes that further work in this direction should proceed with the dolomite samples investigation and selecting the best approximation model describing experimental data in wide range of temperatures, warming up rates and the particle sizes.

Tectonics of the crystalline Basement of the Dolomites in North Italy

NARCIS (Netherlands)

Agterberg, F.P.

1961-01-01

The present thesis deals with a number of crystalline regions around the Dolomites in North Italy. The geographic position is shown on sheet I, which is depicted in fig. 105. The Dolomites proper consist mainly of Permotriassic, overlying a transgression plane, which cuts off the studied crystalline

Dolomitized bryozoan bioherms from the Lower Silurian Manitoulin Formation, Bruce Peninsula, Ontario

Energy Technology Data Exchange (ETDEWEB)

Anastas, A S; Coniglo, M [Waterloo Univ., ON (Canada)

1992-06-01

Several small, previously undescribed bioherms are present in the shallow shelf dolostones of the Manitoulin Formation at the Cabot Head and Wingfield Basin localities in the northernmost portion of the Bruce Peninsula region of southern Ontario. The bioherms, commonly associated with carbonate tempestites, range from 0.3 to 1.0 m in height and 0.9 to 2.5 m in width and are composed of bafflestones-floatstones and minor bindstones. The chief components of the bioherms are dolomitized lime mud and branching bryozoans. Bioherm building by bryozoans, although common in the ancient record, represents a great divergence from the mostly accessory frame encrusting role of bryozoans in modern environments. Minor skeletal components of the bioherms include echinoderms, rugose and tabulate corals and brachiopods. Laminar encrusting bryozoans exist in the top 10 cm of one of the bioherms. Some of the bioherms show evidence of water agitation that may be the result of current action induced by storm or tidal processes. The occurrence of the bioherms stretches the already known Llandoverian reef complex on Manitoulin Island further to the south. The reason why these bioherms did not reach sizes comparable to large Llandoverian or Wenlockian reefs and did not make the shift to coral-stromaporoid community is probably related to a complex interaction of factors such as community development, bathymetry, clasticity and salinity. 41 refs., 4 figs.

Wetland vegetation responses to liming an Adirondack watershed

Energy Technology Data Exchange (ETDEWEB)

Mackun, I.R.

1993-01-01

Watershed liming as a long-term mitigation strategy to neutralize lake acidity, from increasing acid deposition, was initiated in North America at Woods Lake in the west central Adirondack region of New York. In October 1989, a dose of 10 MT lime (83.5% CaCO[sub 3]) ha[sup [minus]1] was aerially applied to 48% of the watershed. The wetlands adjacent to Woods Lake showed two distinct community types: one dominated by Chamaedaphne calyculata, and one dominated by graminoids and other herbaceous species. Within two years, liming did not alter the structure of either community type, and changed the cover or frequency of only 6 of 64 individual taxa. Most of these changes occurred in the herbaceous community type. The only strong positive response to liming was a nearly threefold increase in cover of the rhizomatous sedge Cladium mariscoides. The cover of Carex interior and Sphagnum spp. benefited from lime addition, while cover of Drosera intermedia and Muhlenbergia uniflora, and frequency of Hypericum canadense responded negatively to lime. Liming influenced the competitive release of only three taxa, all forbs with small growth forms. The tissue chemistry of foliage and twigs of Myrica gale, Chamaedaphne calyculata, and Carex stricta in the Chamaedaphne calyculata community type clearly illustrated species-specific patterns of nutrient accumulation and allocation both before and after liming. Concentrations of 17 of 20 elements responded to liming, although the responses varied among species and plant parts. Carex foliage was least responsive to liming, and Chamaedaphne twigs were most responsive. Elemental changes in plant tissues will be reflected in litter and many influence long-term nutrient dynamics in the wetland community.

Phytochemical fingerprints of lime honey collected in serbia.

Science.gov (United States)

Gašić, Uroš; Šikoparija, Branko; Tosti, Tomislav; Trifković, Jelena; Milojković-Opsenica, Dušanka; Natić, Maja; Tešić, Živoslav

2014-01-01

Composition of phenolic compounds and the sugar content were determined as the basis for characterization of lime honey from Serbia. Particular attention was given to differences in phytochemical profiles of ripe and unripe lime honey and lime tree nectar. Melissopalynological analysis confirmed domination of Tilia nectar in all analyzed samples. Phenolic acids, abscisic acid, flavonoids, and flavonoid glycosides were determined by means of ultra-HPLC coupled with a hybrid mass spectrometer (UHPLC-OrbiTrap). Sugar content was determined using high-performance anion-exchange chromatography with amperometric detection. Similar phenolic compounds characterized unripe and ripe honeys, while the lime tree nectar profile showed notable differences. Compared to lime tree nectar, a high amount of chrysin, pinocembrin, and galangin were detected in both ripe and unripe lime honey. Fructose and glucose were the major constituents of all investigated samples, and amounts were within the limits established by European Union legislation. Sucrose content in the nectar sample was up to two-fold higher when compared to all honey samples. Isomaltose and gentiobiose with turanose content were different in analyzed production stages of lime honey.

Study of the creep of lime-stabilised zirconia

International Nuclear Information System (INIS)

Saint-Jacques, Robert G.

1971-09-01

This research thesis reports the study of creep of stabilised zirconia containing between 13 and 20 per cent of lime, at temperatures between 1.200 and 1.400 C, and under compression stresses between 500 and 4.000 pounds by square inch. Specimens are polycrystalline with an average grain diameter between 7 and 29 microns. The author notably shows that the creep rate of lime-stabilised zirconia is directly proportional to the applied stress, and that the creep apparent activation energy is close to activation energy of volume self-diffusion of calcium and zirconium in lime-stabilised zirconia. Results of creep tests show that, in the studied conditions, the creep rate is directly proportional to the inverse of the grain average diameter, and this is in compliance with the Gifkins and Snowden theory of creep by sliding at grain boundaries. The author also shows that the creep rate of the lime stabilised zirconia varies with lime content, and reaches a maximum when zirconia contains about 15 per cent of lime. Lower creep rates obtained for higher and lower lime contents are explained [fr

Energy efficiency opportunity guide in the lime industry

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

The lime industry processes limestone, an abundant inorganic mineral, for metallurgical, industrial and chemical, environmental, and construction applications. The energy the industry uses results in greenhouse gas emissions and the Canadian Lime Institute, in collaboration with Natural Resources Canada, sponsored the development of this guidebook which is intended to provide ideas for saving energy in the lime industry. This document is a practical source of information and can be used to develop self-audit and evaluation techniques to monitor energy usage. The report first provides an overview of the lime industry, then presents its energy costs. General energy efficiency methodologies are highlighted and, in conclusion, advice on improving energy efficiency in general and specifically for lime industry operations is given. This guidebook provides useful information for lime industry operators who are trying to improve the energy efficiency of their operations.

The mechanism of vapor phase hydration of calcium oxide: implications for CO2 capture.

Science.gov (United States)

Kudłacz, Krzysztof; Rodriguez-Navarro, Carlos

2014-10-21

Lime-based sorbents are used for fuel- and flue-gas capture, thereby representing an economic and effective way to reduce CO2 emissions. Their use involves cyclic carbonation/calcination which results in a significant conversion reduction with increasing number of cycles. To reactivate spent CaO, vapor phase hydration is typically performed. However, little is known about the ultimate mechanism of such a hydration process. Here, we show that the vapor phase hydration of CaO formed after calcination of calcite (CaCO3) single crystals is a pseudomorphic, topotactic process, which progresses via an intermediate disordered phase prior to the final formation of oriented Ca(OH)2 nanocrystals. The strong structural control during this solid-state phase transition implies that the microstructural features of the CaO parent phase predetermine the final structural and physicochemical (reactivity and attrition) features of the product hydroxide. The higher molar volume of the product can create an impervious shell around unreacted CaO, thereby limiting the efficiency of the reactivation process. However, in the case of compact, sintered CaO structures, volume expansion cannot be accommodated in the reduced pore volume, and stress generation leads to pervasive cracking. This favors complete hydration but also detrimental attrition. Implications of these results in carbon capture and storage (CCS) are discussed.

Hydration of refractory cements, with spinel phase generated in-situ

International Nuclear Information System (INIS)

Lavat, A.E; Grasselli, M.C; Giuliodori Lovecchio, E

2008-01-01

High alumina refractory materials with additions of synthetic spinel (MgAl 2 O 4 ) have good thermo mechanical and attack from slag properties, which are useful in many technological applications. The spinel phase generated in-situ, MA, has proven to be a suitable and economic alternative to the use of sintered or electrocast spinels. Prior studies have established synthesis conditions for refractory cements with the spinel phase generated in-situ (CCAMA) starting with alumina mixtures and Buenos Aires dolomites. The binding properties of the aluminous cements depend on the hydrated calcium aluminates that form in the setting and hardening stages of the pastes. To avoid breaks, the refractory material must undergo programmed heating before reaching the serviceable temperature. It should also include the present phases and the transformations that occur at different temperatures. In this context knowledge about the green mineral composition and its response to an increase in temperature is especially important. This work presents studies to define the composition of CCAMA cement mortars at different hydration ages, and to estimate phase proportions and behavior during dehydration. DRX and FTIR techniques are applied in order to follow the structural changes that take place during the hydration process. The evolution of the dehydration is also studied, mostly using FTIR. The mortars were prepared with a water/cement ration of 0.5, recommended for this kind of work. The hydration was carried out at room temperature and samples were analyzed at the following ages: 15 min.; 1 h.; 1, 3, 7, 14, 28, 60 and 90 days. With the results the evolution of the phases as a function of the age of the hydration were studied. The main hydrate that was formed was CAH 10 , with a significantly increased proportion during the first 14 days of hydration. Its carbonation was also observed by the presence of calcium carboaluminates and the formation of gibbsite. The MA phase is also

Impact of diagenesis and low grade metamorphosis on Triassic sabkha dolomite δ26Mg

Science.gov (United States)

Immenhauser, A.; Geske, A.; Richter, D.; Buhl, D.; Niedermayr, A.

2012-12-01

Dolomite is a common rock forming mineral in the geological record but its value as archive of ancient seawater δ26Mg signatures and their variations in time are at present underexplored. Unknown factors include the sensitivity of δ26Mg ratio to processes in the diagenetic and low grade metamorphic domain. Here, we document and discusses the first detailed δ26Mg data set from early diagenetic and burial dolomites. Samples come from the Upper Triassic Hauptdolomit (Dolomia Principale; The Dolomites, Italy) and include coeval dolmicrites that underwent differential burial diagenesis in a temperature range between about 100 and more than 350°C. As indicated by dolmicrite 87/86Sr ratios, sabkha calcian D1 dolomites precipitated from evaporated seawater and stabilized at an early diagenetic stage to D2 dolomites analysed here. With increasing burial temperature, dolomite δ26Mg ratio scatter in the data set decreases with increasing Mg/Ca ratio and degree of order. Specifically, δ26Mg ratio variability is reduced from ~0.7‰ at burial temperatures beneath 100°C to about ~0.2‰ at temperatures in excess of 350°C, respectively, with mean δ26Mg values ranging constantly near -1.9‰. This suggests that, at least for the rock buffered system investigated here, dolmicrite δ26Mg proxy data are conservative and preserve near pristine values even at elevated burial temperatures. At present, the main element of uncertainty is the Mg-isotope fractionation factor between (evaporated) seawater and dolomite. A possible solution to this problem includes the compilation of a data from modern sabkha environments including pore water and calcian dolomite δ26Mg isotope signatures.

Corrosion effects on soda lime glass

NARCIS (Netherlands)

Veer, F.A.; Rodichev, Y.M.

2010-01-01

Although soda lime glass is the most common used transparent material in architecture, little is known about the corrosion effects on long term strength and the interaction between corrosion and defects. Extensive testing on soda lime bars under different environmental conditions and different

Engineering Properties of Bentonite Stabilized with Lime and Phosphogypsum

Directory of Open Access Journals (Sweden)

Kumar Sujeet

2014-12-01

Full Text Available Engineering properties such as compaction, unconfined compressive strength, consistency limits, percentage swell, free swell index, the California bearing ratio and the consolidation of bentonite stabilized with lime and phosphogypsum are presented in this paper. The content of the lime and phosphogypsum varied from 0 to 10 %. The results reveal that the dry unit weight and optimum moisture content of bentonite + 8 % lime increased with the addition of 8 % phosphogypsum. The percentage of swell increased and the free swell index decreased with the addition of 8 % phosphogypsum to the bentonite + 8 % lime mix. The unconfined compressive strength of the bentonite + 8 % lime increased with the addition of 8 % phosphogypsum as well as an increase in the curing period up to 14 days. The liquid limit and plastic limit of the bentonite + 8 % lime increased, whereas the plasticity index remained constant with the addition of 8 % phosphogypsum. The California bearing ratio, modulus of subgrade reaction, and secant modulus increased for the bentonite stabilized with lime and phosphogypsum. The coefficient of the consolidation of the bentonite increased with the addition of 8 % lime and no change with the addition of 8 % phosphogypsum.

Biolaminoid facies in a peritidal sabkha: Permian Platy Dolomite of northern Poland

Science.gov (United States)

Brehm, Ulrike; Gasiewicz, Andreij; Gerdes, Giesela; Krumbein, Wolfgang

The Platy Dolomite, a carbonate unit in the Zechstein Formation (Upper Permian) of the Leba Elevation, Poland, was deposited in a semi-closed or completely separated back-barrier sabkha environment. This arid, hypersaline zone is comparable to the recent Gavish Sabkha, Sinai. The processes which formed the modern Gavish Sabkha are similar to those responsible for the biolaminoid formation in the Platy Dolomite series. The deposition of this Platy Dolomite was mainly the result of microbial activity building extensive microbial mats. The Platy Dolomite is characterized by loosely packed microbial biolaminoids (a less significantly laminated build-up of biogenetic sediments) with horizontally or obliquely to vertically orientated filaments. Intermediary coated grains occur. Densely packed, flat laminated stromatolitic rocks, pure oolites, and bioclastic sedimentary strata are rarely intercalated with the biolaminoid beds. Laboratory and field investigations indicate that carbonate formation was induced by the chemoorganotrophic bacterial decay of cyanobacterial mats. Magnesium was bound and absorbed by organic matter and later liberated by anaerobic decay. Early diagenetic processes formed Mg2+- and Ca2+-enriched solutions in which carbonates precipitated biologically and chemically. A system of biogenic carbonate formation of the Platy Dolomite microbiolite series is proposed and supported by the results of microbiological laboratory studies.

Ferroan dolomites in Miocene sediments of the Xisha Islands and their genetic model

Science.gov (United States)

Xu, Hong; Zhang, Weiwei; Wei, Kai; He, Qingkun; Jiang, Yunshui; Xu, Tingting; Jiang, Xuejun; Yan, Guijing; Song, Hongying; Wang, Jianghai

2018-01-01

Carbonate rocks are important reservoirs for global petroleum exploration. The largest oilfield in the South China Sea, Liuhua 11-1, is distributed in the massive carbonate reef area of the Zhujiang (Pearl) River Mouth Basin. Previous studies showed that one 802.17-m-long core from well Xichen-1 in the South China Sea mainly consisted of white and light gray-white organic reefs. Recently, a Miocene whole core (161.9 m long) of well Xiyong-2, near well Xichen-1, was found to contain six layers of yellowish brown, light yellowish gray, iron black, or light yellowish gray-white organic reefs. Scanning electron microscope images of these layers reveal a typical ferroan dolomite rich in Fe (up to 29%), with the high concentrations of Mn, Cu, W, Zn, Cr, Ni, and Co. Systematic X-ray powder diffraction analysis yields a 1.9-6.1 match in phase ratio with ankerite, 5.4-26.9 with dolomite, and zero with calcite, which indicate that the samples can be classified as ferroan dolomite. The iron and heavy metals are inferred to be originated from multiple volcanic eruptions of Gaojianshi Island in the Dongdao Atoll during the middle-late Miocene. These elements were dissolved in seawater, likely as a sol, and carried to Yongxing Island in the Xuande Atoll by sea currents and tides enhanced by prevailing winds, and deposited as a part of the sedimentation process in the study area. The ferroan dolomite has Sr content of (125-285)×10-6, which is lower than the accepted Sr boundary value of dolomite. This finding suggests that dolomitization occurred during large-scale global glacial regression in the late Miocene. The isolated Xisha carbonate platform, exposed to air, underwent freshwater leaching and dolomitization induced by mixed water, and caused the extensive Fe-Mg exchange along the organic reef profile to form ankerite and ferroan dolomite. These results may help to understand paleoceanographic environmental changes in the South China Sea during the Miocene.

First evidence of lime burning in southern Scandinavia: lime kilns found at the royal residence on the west bank of Lake Tissø

DEFF Research Database (Denmark)

Henriksen, Peter Steen; Holst, Sandie

2015-01-01

In connection with investigations of the aristocratic residence at Tissø from the Viking Age, the earliest evidence so far of lime burning in Denmark has been excavated. The excavations unearthed traces of up to five lime kilns which were subsequently dated to the end of the ninth century....... This corresponds well with the dating of the erection of the hall in the third construction phase at Fugledegård. Finds of mud-and-wattle with whitewashing show that the lime was used to whitewash the halls at Tissø in both the Germanic Iron Age and the Viking Age. Analyses of lime from the lime kilns...... and the whitewashed mud-and-wattle demonstrate that the raw material for the lime burning was mainly travertine deposited in spring water, but that bryozoan limestone was also used. The lime kilns were just under 2 m in diameter with stone-built edges, and there are indications that the superstructure may have been...

Lime stabilization of expansive soil from Sergipe - Brazil

Directory of Open Access Journals (Sweden)

Leite Rafaella

2016-01-01

Full Text Available Expansive soils are characterized by volumetric changes caused by variations in moisture. They can cause several damages to civil constructions, especially to lightweight structures, including cracks and fissures. Chemical stabilization through addition of lime is one of the most effective techniques used to treat this type of soil. Due to cationic exchanges, lime can significantly reduce swell potential. This research studied a disturbed sample of expansive soil collected in Nossa Senhora do Socorro – Sergipe, Brazil, through the following laboratory tests: sieve and hydrometer tests, Atterberg Limits, compaction, free swell and swell pressure. All direct and indirect methods mentioned in this paper indicated that the natural soil presented high to very high degree of expansion, which reached approximately 20% of free swell and nearly 200 kPa of swell pressure. In order to evaluate the effect of lime, the same tests were conducted in soil-lime mixtures, using lime contents of 3%, 6% and 9%. The results confirmed the efficiency of lime stabilization. It was noted that, as lime content increased, there was reduction of clay fraction and increment of silt fraction; plasticity index decreased to nearly its half; compaction curve was displaced; and free swell and swell pressure reduced significantly.

Ring Formation in Lime Kilns; Ringbildning i Mesaugnar II

Energy Technology Data Exchange (ETDEWEB)

Dhak, Janice [AaF-Process AB, Stockholm (Sweden)

2003-07-15

The key to a cost efficient and high performance pulp production is low variations in the production level. Despite the fact that all pulp mills always work with improvements to eliminate problems with ring formations, AaF has at several mill seen that the operation of a lime kiln still often is disturbed by ring formation. In 1999 AAF made an extensive investigation of more than 10 lime kilns in Sweden, considering operational data, kiln data and lime chemical analyzes. The result pointed out the importance of how the lime kiln is operated and that dead load and contaminants in the lime was less important. The report suggested that it is the difference in the temperature between the flue gas and the lime that is of importance. There are no quantified process values available that guides for a 'best practice' way to run a lime kiln to avoid ring formation. The goal with this project has been to develop a strategy for operation of a kiln in a way that lowers the risk for ring formation. The results from simulations of a number of lime kilns in this project could not proof that a low difference in the temperature between the flue gas and the lime was the main cause of problems with ring formation and thus it was not possible to quantify the optimal difference to avoid rings. Probably the most important information from the simulations was that it is not the temperature difference in number of degrees that is of importance, rather the fact that the temperature difference in the kalcining zone varies, and time to time reach below the critical level were lime occasionally is cooled down. It can be the case if the temperature profile of the flue gas temporarily changes or if the lime mud temperature profile is changed. The reason for changes in the temperature profile is discussed in the report. The most important factors discussed are: Variations in the energy input e.g. oil and methanol/strong gases in cocombustion. One single fuel is easier to control

Agricultural residues based composites part II: Hydration characteristics of cement- cellulosic fibers composites

International Nuclear Information System (INIS)

Hekal, E.E.; Kishar, E.A.; Abd-El-Khader, A.H.; Ibrahim, A.A.; Mobarak, F.M.

2005-01-01

The aim of this study is the utilization of the local agricultural wastes, such as ice straw bagasse, cotton stalks and linen fibers, which cause a big environmental problem. Different cement-fiber composites were prepared using 1.5, 3, 4.5 and 6% fibers by weight of cement. The lengths of the fibers used were 0.5, 0.8, and 1.25 mm. Hydration of the different, composites was carried out at room temperature for various lime intervals namely, 1.3,7 .28 and 90 days. Combined water contents, compressive strength and phase composition of the different prepared composites were examined

Empirical Calibration for Dolomite Stoichiometry Calculation: Application on Triassic Muschelkalk- Lettenkohle Carbonates (French Jura Calibration empirique pour le calcul de la stoechiométrie de la dolomite : application aux carbonates triasiques du Muschelkalk-Lettenkohle (Jura français

Directory of Open Access Journals (Sweden)

Turpin M.

2012-02-01

Full Text Available This study concerns an approach for dolomite quantification and stoichiometry calculation by using X-ray diffractometry coupled with cell and Rietveld refinements and equipped with a newly substantial database of dolomite composition. A greater accuracy and precision are obtained for quantifying dolomite as well as other mineral phases and calculating dolomite stoichiometry compared to the classical “Lumsden line” and previous methods. The applicability of this approach is verified on dolomite reference material (Eugui and on Triassic (Upper Muschelkalk-Lettenkohle carbonates from the French Jura. The approach shown here is applicable to bulk dolostones as well as to specific dolomite cements and was combined with petrographical and isotopic analyses. Upper Muschelkalk dolomites were formed during burial dolomitization under fluids characterized by increased temperature and variable isotopic composition through burial. This is clear from their Ca content in dolomites which gradually approaches an ideal stoichiometry (from 53.16% to 51.19% through increasing dolomitization. Lettenkohle dolostones consist of near-ideal stoichiometric (51.06%Ca and well-ordered dolomites associated with anhydrite relicts. They originated through both sabkha and burial dolomitization. This contribution gives an improved method for the characterization of different dolomite types and their distinct traits in sedimentary rocks, which allows a better evaluation of their reservoir potential. Cette étude propose une approche pour la quantification de la dolomite et le calcul de sa stoechiométrie grâce à l’utilisation de la diffraction des rayons X couplée aux affinements de maille et de Rietveld et complétée par de nombreuses données issues de la littérature. Elle permet d’obtenir une meilleure justesse et précision pour la quantification de la dolomite (et des autres phases minérales ainsi que pour le calcul de sa stoechiométrie par rapport à l�

Freeze concentration of lime juice

Directory of Open Access Journals (Sweden)

Ampawan Tansakul

2008-11-01

Full Text Available The main objective of this research was to study the effects of processing conditions, i.e. cooling medium temperature (-6, -12 and -18C and scraper blade rotational speed (50, 100 and 150 rpm on the freeze concentration of lime juice. The initial soluble solid content of lime juice was 7.6 Brix. Results showed that soluble solid content of lime juice increased as cooling medium temperature decreased while scraper blade rotational speed increased. It was also found that the processing condition with -18˚C cooling medium temperature and 150 rpm rotational speed of the scraper blade was the best among all studied conditions, although the loss of the soluble solids with ice crystals during ice separation was relatively high at 35%.

Thermal decomposition of dolomite under CO2: insights from TGA and in situ XRD analysis.

Science.gov (United States)

Valverde, Jose Manuel; Perejon, Antonio; Medina, Santiago; Perez-Maqueda, Luis A

2015-11-28

Thermal decomposition of dolomite in the presence of CO2 in a calcination environment is investigated by means of in situ X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The in situ XRD results suggest that dolomite decomposes directly at a temperature around 700 °C into MgO and CaO. Immediate carbonation of nascent CaO crystals leads to the formation of calcite as an intermediate product of decomposition. Subsequently, decarbonation of this poorly crystalline calcite occurs when the reaction is thermodynamically favorable and sufficiently fast at a temperature depending on the CO2 partial pressure in the calcination atmosphere. Decarbonation of this dolomitic calcite occurs at a lower temperature than limestone decarbonation due to the relatively low crystallinity of the former. Full decomposition of dolomite leads also to a relatively low crystalline CaO, which exhibits a high reactivity as compared to limestone derived CaO. Under CO2 capture conditions in the Calcium-Looping (CaL) process, MgO grains remain inert yet favor the carbonation reactivity of dolomitic CaO especially in the solid-state diffusion controlled phase. The fundamental mechanism that drives the crystallographic transformation of dolomite in the presence of CO2 is thus responsible for its fast calcination kinetics and the high carbonation reactivity of dolomitic CaO, which makes natural dolomite a potentially advantageous alternative to limestone for CO2 capture in the CaL technology as well as SO2in situ removal in oxy-combustion fluidized bed reactors.

Use of demolition residues construction in soil-lime bricks

International Nuclear Information System (INIS)

Figueiredo, S.S.; Silva, C.G.; Silva, I.A.; Neves, G.A.

2011-01-01

Besides being responsible for several environmental damage caused by its residues, the construction industry is also considered the greatest natural resources consumer. When finely ground, such residues can exhibit cementing properties, which may replace part of the lime used in the manufacture of soil-lime bricks. This study aimed to verify the viability of using demolition residues (DR) in soil-lime bricks without structural function. For this, test specimens were prepared using mixes in a 1:10 ratio of lime:soil and embedding residue in partial replacement of lime in the proportions of 25%, 50% and 75%. The test specimens were submitted to curing periods of 28 and 52 days, then it was determined the compression strength. The results showed that when embedded on moderate percentages, demolition residues construction can be used in the production of soil-lime bricks. (author)

Optimasi Dosis Pupuk Dolomit pada Tanaman Kelapa Sawit (Elaeis Guineensis Jacq. Belum Menghasilkan Umur Satu Tahun

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- Sudradjat

2015-09-01

Full Text Available Kelapa sawit merupakan komoditi perkebunan utama karena sebagai sumber devisa negara dan menyediakan lapangan kerja. Indonesia adalah negara produsen terbesar kelapa sawit di dunia dengan luas areal mencapai 10.1 juta hektar. Peningkatan produktivitas dicapai dengan intensifikasi antara lain dengan melakukan rasionalisasi pemupkan. Penelitian ini bertujuan untuk menentukan dosis optimum pupuk dolomit pada tanaman kelapa sawit belum menghasilkan umur satu tahun. Penelitian ini dilaksanakan di Kebun Pendidikan dan Penelitian Kelapa Sawit IPB-Cargill, Jonggol, Bogor dari bulan Maret 2013 sampai Maret 2014. Rancangan yang digunakan adalah Faktorial Tunggal,  dosis pupuk dolomit,  yang disusun dalam lingkungan Acak Kelompok dengan tiga ulangan. Dosis pupuk dolomit yang diuji  terdiri atas 0, 200, 400, dan 600 g tanaman-1 tahun-1. Hasil penelitian menunjukkan bahwa pupuk dolomit meningkatkan secara nyata terhadap peubah tinggi tanaman, diameter batang, jumlah daun, dan kandungan khlorofil daun, namun tidak berpengaruh terhadap kandungan Mg dalam jaringan daun. Berdasarkan tanggap peubah tinggi tanaman, dosis optimum pupuk dolomit untuk tanaman kelapa sawit pada umur satu tahun adalah 306.4 g dolomit tanaman-1tahun -1. Kata kunci: dolomit, dosis optimum, kelapa sawit, respons fisiologi, respons morfologi.

Soil pH management without lime, a strategy to reduce greenhouse gas emissions from cultivated soils

Science.gov (United States)

Nadeem, Shahid; Bakken, Lars; Reent Köster, Jan; Tore Mørkved, Pål; Simon, Nina; Dörsch, Peter

2015-04-01

For decades, agricultural scientists have searched for methods to reduce the climate forcing of food production by increasing carbon sequestration in the soil and reducing the emissions of nitrous oxide (N2O). The outcome of this research is depressingly meagre and the two targets appear incompatible: efforts to increase carbon sequestration appear to enhance the emissions of N2O. Currently there is a need to find alternative management strategies which may effectively reduce both the CO2 and N2O footprints of food production. Soil pH is a master variable in soil productivity and plays an important role in controlling the chemical and biological activity in soil. Recent investigations of the physiology of denitrification have provided compelling evidence that the emission of N2O declines with increasing pH within the range 5-7. Thus, by managing the soil pH at a near neutral level appears to be a feasible way to reduce N2O emissions. Such pH management has been a target in conventional agriculture for a long time, since a near-neutral pH is optimal for a majority of cultivated plants. The traditional way to counteract acidification of agricultural soils is to apply lime, which inevitably leads to emission of CO2. An alternative way to increase the soil pH is the use of mafic rock powders, which have been shown to counteract soil acidification, albeit with a slower reaction than lime. Here we report a newly established field trail in Norway, in which we compare the effects of lime and different mafic mineral and rock powders (olivine, different types of plagioclase) on CO2 and N2O emissions under natural agricultural conditions. Soil pH is measured on a monthly basis from all treatment plots. Greenhouse gas (GHG) emission measurements are carried out on a weekly basis using static chambers and an autonomous robot using fast box technique. Field results from the first winter (fallow) show immediate effect of lime on soil pH, and slower effects of the mafic rocks. The

Simple Analysis of Historical Lime Mortars

Science.gov (United States)

Pires, Joa~o

2015-01-01

A laboratory experiment is described in which a simple characterization of a historical lime mortar is made by the determination of its approximate composition by a gravimetric method. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) are also used for the qualitative characterization of the lime mortar components. These…

The stability evaluation of lime mud as transesterification catalyst in resisting CO2 and H2O for biodiesel production

International Nuclear Information System (INIS)

Li, Hui; Niu, Sheng-li; Lu, Chun-mei; Cheng, Shi-qing

2015-01-01

Highlights: • Lime mud (LM) is pretreated with calcination, hydration and desiccation. • The alkali solubility is the amount of alkali compounds dissolved in methanol. • The soluble alkali amount in LM700-H is higher than that of CaO–H. • LM700 possesses a stronger capability than CaO in resisting H 2 O and CO 2 . - Abstract: The most outstanding property of the heterogeneous transesterification catalysts is recyclable, but their catalytic activity may be depressed for the absorption of moisture (H 2 O) and carbon dioxide (CO 2 ) in air, especially for the basic ones. Lime mud (LM) is effective in catalyzing transesterification, yet its property in resisting H 2 O and CO 2 is indistinct, which should be emphasized. In this study, the LM based transesterification catalyst is prepared through calcinations. Then, it is hydrated and desiccated to simulate the contamination by H 2 O and CO 2 . Further, the fresh and the contaminated catalysts are characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Hammette indicator, Brunauer–Emmett–Teller (BET) surface area and soluble alkali examination, to reveal the mechanism of LM in resisting H 2 O and CO 2 . Meanwhile, the analytical grade calcium oxide (CaO) is chosen for comparison. Finally, to comprehensively investigate the influences of H 2 O and CO 2 on LM in catalyzing transesterification, the factors of the catalyst addition percentage, molar ratio of methanol to oil and transesterification temperature are evaluated

Comparative study of engineering properties of two-lime waste tire particle soil and soil with lime/loess ratio of 3:7

Science.gov (United States)

Tiecheng, Yan; Xingyuan, Zhang; Hongping, Yang

2018-03-01

This study describes an analytical comparison of the engineering characteristics of two-lime waste tire particle soil and soil with lime/loess ratio of 3:7 using density measurements, results of indoor consolidation tests, and direct shear tests to examine the strength and deformation characteristics. It investigates the engineering performance of collapsible loess treated with waste tire particles and lime. The results indicate that (1) the shear strength of the two-lime waste tire particle soils increases continuously with soil age; and (2) the two-lime waste tire particle soils are light-weight, strong, and low-deformation soils, and can be applied primarily to improve the foundation soil conditions in areas with collapsible loess soils. This could address the problem of used tire disposal, while providing a new method to consider and manage collapsible loess soils.

Lime treatment of stabilized leachates

International Nuclear Information System (INIS)

Renou, S.; Poulain, S.; Givaudan, J. G.; Sahut, C.; Moulin, P.

2009-01-01

Reverse Osmosis is the most widely used method for treating municipal solid waste landfill leachates, since it produces a permeate in compliance with reject requirements. However, the efficiency of this process at the industrial scale is limited mainly because of membrane fouling and the high osmotic pressures involved. Although lime precipitation is traditionally used to eliminate the temporary hardness of water by de-carbonation, it has also been shown to be highly efficient in removing humic substances which are known to have strong fouling potential towards membranes. Our objective is to study the lime/leachate physico-chemistry, in order to determine the potential of the lime precipitation as pre-treatment for reverse osmosis. The results show that the lime treatment makes it possible (i) to act efficiently on the inorganic fraction of leachates through a de-carbonation mechanism which entails massive precipitation of the carbonates under the form of CaCO 3 , (ii) to eliminate by co-precipitation the high Molecular Weight (MW) organic macromolecules (≥ 50, 000 g.mol -1 ) such as humic acids, and (iii) to generate a stable residue that can be easily stored at a landfill. The reverse osmosis step will be facilitated through significant reduction of the osmotic pressures and prevention of membrane fouling. (authors)

Geology of dolomite-hosted uranium deposits at the Pitch Mine, Saguache County, Colorado

International Nuclear Information System (INIS)

Nash, J.T.

1981-01-01

Newly documented uranium ore in the Pitch mine occurs chiefly in brecciated Mississippian Leadville Dolomite along the Chester upthrust zone, and to a lesser extent in sandstone, siltstone, and carbonaceous shale of the Pennsylvanian Belden Formation and in Precambrian granitic rocks and schist. Uranium-mineralized zones are generally thicker, more consistent, and of higher grade in dolomite than in other hosts, and roughly 50 percent of the new reserves are in dolomite. Strong physical control by dolomite is evident, as this is the only rock type that is pervasively brecciated within the fault slices that make up the footwall of the reverse-fault zone. Other rocks tended to either remain unbroken or undergo ductile deformation. Chemical controls on uranium deposition are subtle and appear chiefly to involve coprecipitation of FeS 2 as pyrite and marcasite, suggesting that sulfide ion may be the reductant

Origins and Geochemistry of Oolitic Dolomite of the Feixianguan Formation from the Yudongzi Outcrop, Northwest Sichuan Basin, China

Directory of Open Access Journals (Sweden)

Liya Zhang

2017-07-01

Full Text Available The topic of dolomite formation has long presented a challenge to researchers. In this study, the origin of widely occurring oolitic dolomites from the Yudongzi outcrop in the lower Triassic Feixianguan formation in northwest Sichuan, China, was investigated through petrographic observations, and mineralogical and geochemical analysis. Analytical methods used include cathodoluminescence, X-ray diffraction, stable isotopes, and electronic microprobe characterization. The dolomites were categorized into three major genetic types according to their textural and structural characteristics, which reflect their various origins. The first genetic type of these dolomites, seepage reflux dolomitization, occurs in marly to microcrystalline dolomite during the penecontemporaneous stage, and displays negatively skewed δ18Ο (−2.83‰ Pee Dee Belemnite (PDB, positively skewed δ13C (2.71‰ PDB, a low degree of order (0.48, and 87Sr/86Sr ratios of 0.707509–0.707634, indicating involvement of a Mg-rich brine fluid in an open evaporative environment. The second type, shallow burial dolomitization, is the most significant genetic type of dolomite reservoir in this area. This process produced dominantly silty to fine crystalline dolomite in a platform-margin oolitic beach facies with negatively skewed δ18Ο (−3.26‰ PDB, positively skewed δ13C (1.88‰ PDB, a high degree of order (0.70, and 87Sr/86Sr ratios of 0.707318–0.707661, which are related to seawater-derived fluids in a shallow burial environment. The third type is moderate to deep burial dolomitization, and is the main process responsible for zoned dolomite and dolomite with cloudy cores and clear rims (CCCR dolomite, which have the most strongly negatively skewed δ18Ο (−7.32‰ PDB, positively skewed δ13C (3.02‰ PDB, and 87Sr/86Sr ratios of 0.707217–0.707855, representing diagenetic alteration and fluid flow in a closed environment. These findings indicate that dolomite was likely

Lime in gold and uranium mining

International Nuclear Information System (INIS)

Van Staden, C.M.

1979-01-01

In this article the author discusses the role of lime in gold and uranium extraction and looks more closely at the industry's efforts to improve the environment by vegetation of sand dumps and slimes dams. He then comes to the conclusion that lime has been and still is the most effective, practical and cheapest chemical that can be used in the South African gold and uranium mining industry to settle pulps, protect cyanide solutions, aid the vegetation of dumps and neutralise acidic waters and residues. The gold and uranium industry is very pollution concious, and in South Africa the importance of the role that lime plays in combating air and water pollution cannot be over emphasised

Ecological comparison between hydrated lime and sodium bicarbonate when used for dry flue gas purification; Oekologischer Vergleich von Kalkhydrat und Natriumbicarbonat beim Einsatz in der trockenen Rauchgasreinigung

Energy Technology Data Exchange (ETDEWEB)

Wecker, Andreas [Federal German Association of the Lime Industry, Koeln (Germany)

2009-07-01

Lime plays an important role in environmental protection. Not only due to its properties but also due to its natural occurrence, it is suitable and accepted for universal application in the environment sector. Lime and its refined products can be used in various processes to remove the acid gases, the gaseous metal compounds and organic trace constituents from the flue gas of waste incineration plants. The choice of the suitable process depends on the raw gas load, the separation efficiency to be achieved and the way of recovery of the reaction product obtained as a result of flue gas cleaning. The dry sorption processes have been established for many years and have been continuously further developed, in which lime is injected into the flue gas flow and the reaction product is retained via a filtering separator. As an alternative to lime products, it is also possible, under certain boundary conditions, to use sodium hydrogen-carbonate NaHCO{sub 3} (below called sodium bicarbonate) as a basic reaction component in the dry sorption process. As opposed to calcium hydroxide, there are differences, for example as regards the reaction temperature required and the necessary amount of sorbent to achieve the desired purification effect. (orig.)

Neutralising acid mine waters underground

Energy Technology Data Exchange (ETDEWEB)

Aminov, A S

1978-09-01

It is essential to treat acid mine drainage in order to avoid its corrosive effects on plant and equipment. Neutralisation aims at increasing the pH to 7 and is carried out using lime, limestone or dolomite, in conjunction with aeration. Use of residues from settling ponds to slake the lime increases economy in water and lime, improves sedimentation and provides a better and more even sediment.

The kinetics of dolomite reaction rim growth under isostatic and non-isostatic pressure conditions

Science.gov (United States)

Helpa, V.; Rybacki, E.; Morales, L. G.; Abart, R.; Dresen, G. H.

2013-12-01

During burial and exhumation, rocks are simultaneously exposed to metamorphic reactions and tectonic stresses. Therefore, the reaction rate of newly formed minerals may depend on chemical and mechanical driving forces. Here, we investigate the reaction kinetics of dolomite (CaMg[CO3]2) rim growth by solid-state reactions experiments on oriented calcite (CaCO3) and magnesite (MgCO3) single crystals under isostatic and non-isostatic pressure conditions. Cylindrical samples of 3-5 mm length and 7 mm diameter were drilled and polished perpendicular to the rhombohedral cleavage planes of natural clear crystals. The tests were performed using a Paterson-type deformation apparatus at P = 400 MPa confining pressure, temperatures, T, between 750 and 850°C, and reaction durations, t, of 2 - 146 h to calculate the kinetic parameters of dolomite rim growth under isostatic stress conditions. For non-isostatic reaction experiments we applied in addition differential stresses, σ, up to 40 MPa perpendicular to the contact interface at T = 750°C for 4 - 171 h duration, initiating minor inelastic deformation of calcite. The thickness of the resulting dolomite reaction rims increases linearly with the square root of time, indicating a diffusion-controlled reaction. The rims consist of two different textural domains. Granular dolomite grains (≈ 2 -5 μm grain size) form next to calcite and elongated palisade-shaped grains (1-6 μm diameter) grow perpendicular to the magnesite interface. Texture measurements with the electron backscatter diffraction technique indicate that the orientations of dolomite grains are mainly influenced by the orientation of the calcite educt crystal, in particular in the granular rim. To some extent, the texture of dolomite palisades is also influenced by the orientation of magnesite. The thickness of the two individual layers increases with temperature. At 400 MPa isostatic pressure, T = 750°C and t = 29 hours, a 5 μm thick granular dolomite layer

Effect of addition of Sikament-R superplasticizer on the hydration characteristics of portland cement pastes

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Safaa.M. El Gamal

2012-08-01

Full Text Available The effect of addition of Sikament-R superplasticizer (modified lignosulphonate base on the hydration characteristics of hardened Portland cement pastes were studied at different curing conditions. Four mixtures were prepared using 0, 0.2, 0.4 and 0.6 wt% addition of Sikament-R superplasticizer (SR of cement. These pastes were hydrated under two different conditions; (i normal curing at room temperature; 25 °C up to 90 days periods and (ii hydrothermal curing at a pressure of 8 atm. of saturated steam up to 24 h. The compressive strength, combined water content, free lime content, gel/space ratio and microstructure of hardened cement pastes were studied. The results revealed that addition of SR superplasticizer promote the dispersion of cement particles and interacts with Ca(OH2. The addition of SR superplasticizer exhibits Portland cement better workability during the preparation of pastes. In addition, amore compact structure were obtained leading to higher values of compressive strength for all the hardened hydrated pastes under both normal and hydrothermal curing. The results indicated that the addition of SR superplasticizer to Portland cement does not alter the types of hydration products formed during normal or hydrothermal conditions; only it caused a decrease in the degree of the porosity of the formed pastes.

Time evolution of pore system in lime - Pozzolana composites

Science.gov (United States)

Doleželová, Magdaléna; Čáchová, Monika; Scheinherrová, Lenka; Keppert, Martin

2017-11-01

The lime - pozzolana mortars and plasters are used in restoration works on building cultural heritage but these materials are also following the trend of energy - efficient solutions in civil engineering. Porosity and pore size distribution is one of crucial parameters influencing engineering properties of porous materials. The pore size distribution of lime based system is changing in time due to chemical processes occurring in the material. The present paper describes time evolution of pore system in lime - pozzolana composites; the obtained results are useful in prediction of performance of lime - pozzolana systems in building structures.

Balancing guava nutrition with liming and fertilization

Directory of Open Access Journals (Sweden)

Amanda Hernandes

2012-12-01

Full Text Available Guava response to liming and fertilization can be monitored by tissue testing. Tissue nutrient signature is often diagnosed against nutrient concentration standards. However, this approach has been criticized for not considering nutrient interactions and to generate numerical biases as a result of data redundancy, scale dependency and non-normal distribution. Techniques of compositional data analysis can control those biases by balancing groups of nutrients, such as those involved in liming and fertilization. The sequentially arranged and orthonormal isometric log ratios (ilr or balances avoid numerical bias inherent to compositional data. The objectives were to relate tissue nutrient balances with the production of "Paluma" guava orchards differentially limed and fertilized, and to adjust the current patterns of nutrient balance with the range of more productive guava trees. It was conducted one experiment of 7-yr of liming and three experiments of 3-yr with N, P and K trials in 'Paluma' orchards on an Oxisol. Plant N, P, K, Ca and Mg were monitored yearly. It was selected the [N, P, K | Ca, Mg], [N, P | K], [N | P] and [Ca | Mg] balances to set apart the effects of liming (Ca-Mg and fertilizers (N-K on macronutrient balances. Liming largely influenced nutrient balances of guava in the Oxisol while fertilization was less influential. The large range of guava yields and nutrient balances allowed defining balance ranges and comparing them with the critical ranges of nutrient concentration values currently used in Brazil and combined into ilr coordinates.

46 CFR 148.04-23 - Unslaked lime in bulk.

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Unslaked lime in bulk. 148.04-23 Section 148.04-23... HAZARDOUS MATERIALS IN BULK Special Additional Requirements for Certain Material § 148.04-23 Unslaked lime in bulk. (a) Unslaked lime in bulk must be transported in unmanned, all steel, double-hulled barges...

Effect of lime concentration on gelatinized maize starch dispersions properties.

Science.gov (United States)

Lobato-Calleros, C; Hernandez-Jaimes, C; Chavez-Esquivel, G; Meraz, M; Sosa, E; Lara, V H; Alvarez-Ramirez, J; Vernon-Carter, E J

2015-04-01

Maize starch was lime-cooked at 92 °C with 0.0-0.40% w/w Ca(OH)2. Optical micrographs showed that lime disrupted the integrity of insoluble remnants (ghosts) and increased the degree of syneresis of the gelatinized starch dispersions (GSD). The particle size distribution was monomodal, shifting to smaller sizes and narrower distributions with increasing lime concentration. X-ray patterns and FTIR spectra showed that crystallinity decreased to a minimum at lime concentration of 0.20% w/w. Lime-treated GSD exhibited thixotropic and viscoelastic behaviour. In the linear viscoelastic region the storage modulus was higher than the loss modulus, but a crossover between these moduli occurred in the non-linear viscoelastic region. The viscoelastic properties decreased with increased lime concentration. The electrochemical properties suggested that the amylopectin-rich remnants and the released amylose contained in the continuous matrix was firstly attacked by calcium ions at low lime levels (<0.20% w/w), disrupting the starch gel microstructure. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ecological indices of manufacture of Portland cement clinker and production of the dolomite clinker

Directory of Open Access Journals (Sweden)

Vinnichenko Varvara

2017-01-01

Full Text Available It is shown that the production of dolomite clinker in comparison with that of Portland cement is environmentally appropriate. When calcining dolomite for cementitious binder, the pollution of the atmosphere by carbon dioxide is reduced due to its isolation during decarbonization reactions of calcium carbonates. Reducing fuel consumption for clinker burning provides less carbon dioxide emissions from combustion products. Reducing the firing temperature creates obstacles to the formation of nitrogen oxides. The production of binders from dolomite in comparison with the production of Portland cement helps to protect the environment from contamination

[Study on Archaeological Lime Powders from Taosi and Yinxu Sites by FTIR].

Science.gov (United States)

Wei, Guo-feng; Zhang, Chen; Chen, Guo-liang; He, Yu-ling; Gao, Jiang-tao; Zhang, Bing-jian

2015-03-01

Archaeological lime powders samples from Taosi and Yinxu sites, natural limestone and experimentally prepared lime mortar were investigated by means of Fourier transform infrared spectrometry (FTIR) to identify the raw material of lime powders from Taosi and Yinxu sites. Results show that ν2/ν4 ratio of calcite resulted from carbonation reaction of man-made lime is around 6.31, which is higher than that of calcite in natural limestone and reflects the difference in the disorder of calcite crystal structure among the natural limestone and prepared lime mortar. With additional grinding, the values of v2 and ν4 in natural limestone and prepared lime mortar decrease. Meanwhile, the trend lines of ν2 versus ν4 for calcite in experimentally prepared lime mortar have a steeper slope when compared to calcite in natural limestone. These imply that ν2/ν4 ratio and the slope of the trend lines of ν2 versus ν4 can be used to determine the archaeological man-made lime. Based on the experiment results, it is possible that the archaeological lime powder from Taosi and Yinxu sites was prepared using man-made lime and the ancient Chinese have mastered the calcining technology of man-made lime in the late Neolithic period about 4 300 years ago.

Characterisation of Asphalt Concrete Using Nanoindentation.

Science.gov (United States)

Barbhuiya, Salim; Caracciolo, Benjamin

2017-07-18

In this study, nanoindentation was conducted to extract the load-displacement behaviour and the nanomechanical properties of asphalt concrete across the mastic, matrix, and aggregate phases. Further, the performance of hydrated lime as an additive was assessed across the three phases. The hydrated lime containing samples have greater resistance to deformation in the mastic and matrix phases, in particular, the mastic. There is strong evidence suggesting that hydrated lime has the most potent effect on the mastic phase, with significant increase in hardness and stiffness.

Effects of corn cob ash on lime stabilized lateritic soil

Science.gov (United States)

Nnochiri, Emeka Segun

2018-03-01

This study assesses the effects of Corn Cob Ash (CCA) on lime-stabilized lateritic soil. Preliminary tests were carried out on the natural soil sample for purpose of identification and classification. Lime being the main stabilizing material was thoroughly mixed with the soil sample to determine the optimum lime requirement of the sample as a basis for evaluating the effects of the CCA. The optimum lime requirement was 10%. The CCA was thereafter added to the lime stabilized soil in varying proportions of 2, 4, 6, 8 and 10%. Unsoaked CBR increased from 83% at 0% CCA to highest value of 94% at 4% CCA. Unconfined Compressive Strength (UCS) values increased from 1123kN/m2 at 0% CCA to highest value of 1180kN/m2 at 4% CCA. It was therefore concluded that CCA can serve as a good complement for lime stabilization in lateritic soil.

New insight into atmospheric alteration of alkali-lime silicate glasses

International Nuclear Information System (INIS)

Alloteau, Fanny; Lehuédé, Patrice; Majérus, Odile; Biron, Isabelle; Dervanian, Anaïs; Charpentier, Thibault; Caurant, Daniel

2017-01-01

Highlights: •Glass silicate network hydrolysis is by far the predominant reaction at 80 °C. •Atmospheric conditions yield different altered layer structure than in immersion. •The altered layer bears about 10 wt% of water mainly as H-bonded SiOH groups. •Alkali ions stay embedded into the altered layer closed to SiOH and H 2 O species. -- Abstract: A mixed alkali lime silicate glass altered in atmospheric conditions (80 °C/85%RH, Relative Humidity) for various lengths of time was characterized at all scales. The altered glass forms a hydrated solid phase bearing about 10 wt% of H 2 O in the form of Si-OH groups and molecular water. No alkali depletion was observed after ageing tests. Structural results from 1 H, 23 Na and 29 Si MAS NMR point out the close proximity of Si-OH, H 2 O and Na + species. This study gives new insight into the mechanisms of the atmospheric alteration, essential to conservation strategies in industry and cultural heritage.

Optimization of lime treatment processes

International Nuclear Information System (INIS)

Zinck, J. M.; Aube, B. C.

2000-01-01

Lime neutralization technology used in the treatment of acid mine drainage and other acidic effluents is discussed. Theoretical studies and laboratory experiments designed to optimize the technology of lime neutralization processes and to improve the cost efficiency of the treatment process are described. Effluent quality, slaking temperature, aeration, solid-liquid separation, sludge production and geochemical stability have been studied experimentally and on site. Results show that through minor modification of the treatment process, costs, sludge volume generated, and metal released to the environment can be significantly reduced. 17 refs., 4 figs

The influence of solution composition and grain boundaries on the replacement of calcite by dolomite

Science.gov (United States)

Moraila Martinez, Teresita de Jesus; Putnis, Christine V.; Putnis, Andrew

2016-04-01

Dolomite formation is a mineral replacement reaction that affects extensive rock volumes and comprises a large fraction of oil and gas reservoirs [1,2]. The most accepted hypothesis is the 'dolomitization' of limestone by Mg-rich fluids [3]. The objective of this research is to study the replacement mechanism of calcite by dolomite, the role of grain boundaries, highlighted by Etschmann et al. (2014), and the possible influence of solutions in dolomite formation under the presence of ions that are normally in crustal aqueous fluids. To accomplish this purpose, we performed hydrothermal experiments using Carrara marble cubes of ~1.5 mm size and 7-9 mg weight as starting material, reacted with 1M (Mg,Ca)Cl2 aqueous solutions, with Mg/Ca ratios of 3 and 5 at 200°C, for different reaction times. Additional experiments were performed adding 1mM of Na2SO4, NaCl or NaF to the previous solutions. After the reaction, the product phases were identified using Raman spectroscopy, X-Ray powder diffraction (XRD), electron microprobe analysis (EMPA), and the textural evolution was studied by scanning electron microscopy (SEM). Samples reacted with aqueous solutions resulted in the replacements of the calcite rock into magnesite and dolomite. The amount and type of reaction strongly depends on the Mg/Ca ratio. Samples reacted with a Mg/Ca ratio of 5 resulted in an almost complete replacement reaction and more favorable for magnesite formation than for dolomite. When the Mg/Ca ratio was 3 dolomite formed but the replacement was located in the core of the sample. We show that grain boundaries are very important for the infiltration of solution and the progress of a replacement reaction, acting as fluid pathways. Solution composition controls the nature of the replacement product. Acknowledgment: This work is funded within a Marie Curie EU Initial Training Network- CO2-React. 1. Etschmann B., Brugger J., Pearce M.A., Ta C., Brautigan D., Jung M., Pring A. (2014). Grain boundaries as

Characteristic Asphalt Concrete Wearing Course (ACWC) Using Variation Lime Filler

Science.gov (United States)

Permana, R. A.; Pramesti, F. P.; Setyawan, A.

2018-03-01

This research use of lime filler Sukaraja expected add durability layers of concrete pavement is asphalt damage caused by the weather and load traffic. This study attempts to know how much value characteristic Marshall on a mixture of concrete asphalt using lime filler. This research uses experimental methods that is with a pilot to get results, thus will look filler utilization lime on construction concrete asphalt variation in filler levels 2 %, 3 %, 4 %.The results showed that the use of lime filler will affect characteristic a mixture of concrete asphalt. The more filler chalk used to increase the value of stability. On the cretaceous filler 2 % value of stability is 1067,04 kg. When lime filler levels added to the levels of filler 4 %, the value of stability increased to 1213,92 kg. The flexibility increased the number of filler as levels lime 2 % to 4 % suggests that are conducted more stiff mix.

Liming as a method to remedy lakes contaminated by radiostrontium

International Nuclear Information System (INIS)

Haakanson, Lars

2003-01-01

This work has identified the characteristics regulating lake sensitivity to 90 Sr-contamination and why certain lakes are likely to respond positively to lake liming (Ca-treatment) and when this would not be a feasible or economic remedial measure to lower 90 Sr-levels in fish. The results demonstrate that liming would work best in (1) small, (2) low-productive, (3) oligohumic, (4) acid lakes with (5) low initial Ca-concentrations. It is important to start the liming as soon as possible after the fallout. The liming model discussed in this work can be used to calculate the changes in lake Ca-concentrations and the duration of the liming. The Sr-model can be used to calculate changes in Sr-levels in water, sediments and fish. At best, these simulations indicate that it is realistic to expect that lake liming can reduce peak levels of 90 Sr in fish by 25-40%

Short-term responses of wetland vegetation after liming of an Adirondack watershed

Energy Technology Data Exchange (ETDEWEB)

Mackun, I.R.; Leopold, D.J.; Raynal, D.J. (State Univ. of New York, Syracuse, NY (United States))

1994-08-01

Watershed liming has been suggested as a long-term mitigation strategy for lake acidity, particularly in areas subject to high levels of acidic deposition. However, virtually no information has been available on the impacts of liming on wetland vegetation. In 1989, 1100 Mg of limestone (83.5% CaCO[sub 3]) were aerially applied to 48% (100 ha) of the Woods Lake watershed in the west-central Adirondack region of New York as part of the first comprehensive watershed liming study in North America. We inventoried wetland vegetation in 1.0-m[sup 2] plots before liming and during the subsequent 2 yr. Within this period liming influenced the cover, frequency, or importance values of only 6 of 64 wetland taxa. The cover of Sphagnum spp. and of the cespitose sedge Carex interior decreased in control relative to limed plots, and cover of the rhizomatous sedge Cladium mariscoides increased nearly threefold in limed areas. These two sedges, which are relatively tall, are characteristic of more calcareous habitats. Cover of the grass Muhlenbergia uniflora, cover and importance were adversely affected or inhibited by lime. It is unclear whether liming directly inhibited the growth of these three small-statured species, or whether the adverse effects of lime were mediated through shifts in competitive interactions with other species. The limited responses that we observed to liming, along with changes that occurred in control plots over the study period, may indicate that in the short term watershed liming was no more of a perturbation than the environmental factors responsible for natural annual variation in wetland communities.

Liming impacts on soils, crops and biodiversity in the UK: A review.

Science.gov (United States)

Holland, J E; Bennett, A E; Newton, A C; White, P J; McKenzie, B M; George, T S; Pakeman, R J; Bailey, J S; Fornara, D A; Hayes, R C

2018-01-01

Fertile soil is fundamental to our ability to achieve food security, but problems with soil degradation (such as acidification) are exacerbated by poor management. Consequently, there is a need to better understand management approaches that deliver multiple ecosystem services from agricultural land. There is global interest in sustainable soil management including the re-evaluation of existing management practices. Liming is a long established practice to ameliorate acidic soils and many liming-induced changes are well understood. For instance, short-term liming impacts are detected on soil biota and in soil biological processes (such as in N cycling where liming can increase N availability for plant uptake). The impacts of liming on soil carbon storage are variable and strongly relate to soil type, land use, climate and multiple management factors. Liming influences all elements in soils and as such there are numerous simultaneous changes to soil processes which in turn affect the plant nutrient uptake; two examples of positive impact for crops are increased P availability and decreased uptake of toxic heavy metals. Soil physical conditions are at least maintained or improved by liming, but the time taken to detect change varies significantly. Arable crops differ in their sensitivity to soil pH and for most crops there is a positive yield response. Liming also introduces implications for the development of different crop diseases and liming management is adjusted according to crop type within a given rotation. Repeated lime applications tend to improve grassland biomass production, although grassland response is variable and indirect as it relates to changes in nutrient availability. Other indicators of liming response in grassland are detected in mineral content and herbage quality which have implications for livestock-based production systems. Ecological studies have shown positive impacts of liming on biodiversity; such as increased earthworm abundance that

Action time effect of lime on its depressive ability for pyrite

Institute of Scientific and Technical Information of China (English)

Tichang Sun

2004-01-01

Two sample groups of bulk concentrates consisting mainly of pyrite and chalcopyrite from Daye and Chenghchao Mines in Hubei Province of China were used to investigate the effect of the action time of lime on its depressive ability for pyrite. The experimental results conducted with different samples and collectors showed that the action time between lime and pyrite markedly influences the depressive ability of lime. The depressive ability of lime increased with the action time increasing. It was also proved that the depressive results obtained at a large lime dosage after a shorter action time are similar to those obtained at a small lime dosage after a longer action time. The increase of depressive ability of lime after a longer action time is because that there are different mechanisms in different action time. The composition on the surface of pyrite acted for different time with lime was studied by using ESCA (Electron Spectroscopic Chemical Analysis). The results showed that iron hydroxide and calcium sulphate formed on the pyrite surface at the presence of lime in the pulp but the amounts of iron hydroxide and calcium sulphate were different at different action time. At the beginning action time the compound formed on the pyrite surface was mainly calcium sulphate and almost no iron hydroxide formed; but with the action time increasing, iron hydroxide formed. The longer the action time, the more iron hydroxide and the less calcium sulphate formed. It was considered that the stronger depressive ability of lime after a longer action time is because more iron hydroxide forms on the pyrite surface.

Experimental investigation and constitutive model for lime mudstone.

Science.gov (United States)

Wang, Junbao; Liu, Xinrong; Zhao, Baoyun; Song, Zhanping; Lai, Jinxing

2016-01-01

In order to investigate the mechanical properties of lime mudstone, conventional triaxial compression tests under different confining pressures (0, 5, 15 and 20 MPa) are performed on lime mudstone samples. The test results show that, from the overall perspective of variation law, the axial peak stress, axial peak strain and elastic modulus of lime mudstone tend to gradually increase with increasing confining pressure. In the range of tested confining pressure, the variations in axial peak stress and elastic modulus with confining pressure can be described with linear functions; while the variation in axial peak strain with confining pressure can be reflected with a power function. To describe the axial stress-strain behavior in failure process of lime mudstone, a new constitutive model is proposed, with the model characteristics analyzed and the parameter determination method put forward. Compared with Wang' model, only one parameter n is added to the new model. The comparison of predicted curves from the model and test data indicates that the new model can preferably simulate the strain softening property of lime mudstone and the axial stress-strain response in rock failure process.

Model study of initial adsorption of SO2 on calcite and dolomite

International Nuclear Information System (INIS)

Malaga-Starzec, Katarina; Panas, Itai; Lindqvist, Oliver

2004-01-01

The rate of calcareous stone degradation is to a significant extent controlled by their surface chemistry with SO 2 . Initial surface sulphite is converted to a harmful gypsum upon, e.g. NO 2 catalysed oxidation. However, it has been observed by scanning electron microscopy that the lateral distributions of gypsum crystals differ between calcitic and dolomitic marbles. The first-principles density functional theory is employed to understand the origin of these fundamentally different morphologies. Here, the stability differences of surface sulphite at calcite CaCO 3 (s) and dolomite Ca x Mg 1-x CO 3 (s) are determined. A qualitative difference in surface sulphite stability, favouring the former, is reported. This is taken to imply that calcitic micro-crystals embedded in a dolomitic matrix act as sinks in the surface sulphation process, controlled by SO 2 diffusion. The subsequent formation of gypsum under such conditions will not require SO 4 2- (aq) ion transport. This explains the homogeneous distribution of gypsum observed on the calcitic micro-crystals in dolomite. In contrast, sulphation on purely calcitic marbles never reaches such high SO 2 coverage. Rather, upon oxidation, SO 4 2- (aq) transport to nucleation centres, such as grain boundaries, is required for the growth of gypsum crystals

Messinian Salinity Crisis' Primary Evaporites: the shallow gypsum vs. deep dolomite formation paradox solved

Science.gov (United States)

De Lange, G. J.; Krijgsman, W.

2015-12-01

The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, resulting in deposition of 1-3 km thick evaporites at the Mediterranean seafloor. A considerable, long-lasting controversy existed on the modes of their formation, including the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions at a precessional rhythm. Gypsum precipitation only occurred at marginal- and dolomite formation at deeper settings. A range of potential explanations was given, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are commonly neglected but may explain that different deposits formed in shallow vs deep environments without exceptional physical boundary conditions for each. A unifying mechanism is presented in which gypsum formation occurs at all shallow water depths but its preservation is limited to shallow sedimentary settings. In contrast, ongoing deep-basin anoxic organic matter (OM) degradation processes result in dolomite formation. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always oversaturated relative to dolomite but its formation is inhibited by the presence of dissolved sulphate. Thus conditions for formation of gypsum exclude those for formation of dolomite and vice versa. Another process linking the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, ongoing OM-degradation may result in reducing the sulphate and enhancing the dissolved carbonate content. Such low-sulphate / high carbonate conditions in MSC deepwater are. unfavorable for gypsum preservation and favorable for dolomite formation, and always coincide with anoxic, i.e. oxygen-free conditions. Including dynamic biogeochemical processes in the thusfar static

Peat Soil Stabilization using Lime and Cement

Directory of Open Access Journals (Sweden)

Mohd Zambri Nadhirah

2018-01-01

Full Text Available This paper presents a study of the comparison between two additive Lime and Cement for treating peat soil in term of stabilization. Peat and organic soils are commonly known for their high compressibility, extremely soft, and low strength. The aim of this paper is to determine the drained shear strength of treated peat soil from Perlis for comparison purposes. Direct Shear Box Test was conducted to obtain the shear strength for all the disturbed peat soil samples. The quick lime and cement was mixed with peat soil in proportions of 10% and 20% of the dry weight peat soil. The experiment results showed that the addition of additives had improved the strength characteristics of peat soil by 14% increment in shear strength. In addition, the mixture of lime with peat soil yield higher result in shear strength compared to cement by 14.07% and 13.5% respectively. These findings indicate that the lime and cement is a good stabilizer for peat soil, which often experienced high amount of moisture content.

Peat Soil Stabilization using Lime and Cement

Science.gov (United States)

Zambri, Nadhirah Mohd; Ghazaly, Zuhayr Md.

2018-03-01

This paper presents a study of the comparison between two additive Lime and Cement for treating peat soil in term of stabilization. Peat and organic soils are commonly known for their high compressibility, extremely soft, and low strength. The aim of this paper is to determine the drained shear strength of treated peat soil from Perlis for comparison purposes. Direct Shear Box Test was conducted to obtain the shear strength for all the disturbed peat soil samples. The quick lime and cement was mixed with peat soil in proportions of 10% and 20% of the dry weight peat soil. The experiment results showed that the addition of additives had improved the strength characteristics of peat soil by 14% increment in shear strength. In addition, the mixture of lime with peat soil yield higher result in shear strength compared to cement by 14.07% and 13.5% respectively. These findings indicate that the lime and cement is a good stabilizer for peat soil, which often experienced high amount of moisture content.

Aplicação superficial de diferentes fontes de corretivos no crescimento radicular e produtividade da aveia preta Surface application by different lime source in root growth and yield of black oat

Directory of Open Access Journals (Sweden)

Juliano Corulli Corrêa

2008-08-01

lime materials were surface-applied. The treatments consisted of surface applications of centrifuged sewage sludge, flue dust, aqueous lime, dolomitic lime and an unlimed control arranged in a randomized complete block design with four replications. Surface application of lime, flue dust, aqueous lime and sewage sludge increased soil pH, exchangeable Ca, resin P and reduced the exchangeable Al in soil. Black oat root growth, above-ground dry matter and grain yield increased with surface applications of the different lime sources in no-till system.

Plasticity, Swell-Shrink, and Microstructure of Phosphogypsum Admixed Lime Stabilized Expansive Soil

OpenAIRE

James, Jijo; Pandian, P. Kasinatha

2016-01-01

The study involved utilization of an industrial waste, Phosphogypsum (PG), as an additive to lime stabilization of an expansive soil. Three lime dosages, namely, initial consumption of lime (ICL), optimum lime content (OLC), and less than ICL (LICL), were identified for the soil under study for stabilizing the soil. Along with lime, varying doses of PG were added to the soil for stabilization. The effect of stabilization was studied by performing index tests, namely, liquid limit, plastic lim...

Towards the industrial solar production of lime

Energy Technology Data Exchange (ETDEWEB)

Meier, A.; Bonaldi, E. [QualiCal SA, Bergamo (Italy); Cella, G.M. [QualiCal SA, Bergamo (Italy); Lipinski, W.; Palumbo, R.; Steinfeld, A. [ETH Zuerich (Switzerland) and PSI; Wieckert, C.; Wuillemin, D.

2002-03-01

A new industrial concept that aims at the development of the chemical engineering technology for the solar production of lime is being examined. To establish the technical feasibility, a 10 kW solar reactor has been designed, constructed, and experimentally tested at a high-flux solar furnace. The quality of the produced solar lime meets industrial standards. (author)

Hydrogen Chloride Reaction with Lime and Limestone

DEFF Research Database (Denmark)

Erik Weinell, Claus; Jensen, Peter I.; Dam-Johansen, Kim

1992-01-01

The capacity of solid slaked lime and limestone for binding HCl from a gas phase has been investigated in the temperature range 60-1000 °C. The binding capacity is largest in the range 500-600 °C. However, for slaked lime in the presence of water, a large binding capacity is observed also below 150...

Dissolution Kinetics of Icel-Aydincik Dolomite in Hydrochloric Acid

African Journals Online (AJOL)

NJD

Department of Mining Engineering, Faculty of Engineering and Architecture, Cukurova University, Balcali, ... 65 °C. It was observed that heterogeneous chemical reactions ..... Dolomite, Ph.D. thesis, Cukurova University, Adana, Turkey, 2004.

Effects of Palm Kernel Shell Ash on Lime-Stabilized Lateritic Soil

Science.gov (United States)

Nnochiri, Emeka Segun; Ogundipe, Olumide M.; Oluwatuyi, Opeyemi E.

2017-09-01

The research investigated the effects of palm kernel shell ash (PKSA) on lime-stabilized lateritic soil. Preliminary tests were performed on three soil samples, i.e., L1, L2 and L3 for identification; the results showed that L1 was A-7-6, L2 was A-7-6, and L3 was A-7-6. The optimum amount of lime for each of the soil samples was achieved. The optimum amount for L1 was 10%, for L2, 8% and for L3, 10%; at these values they recorded the lowest plasticity indexes. The further addition of PKSA was performed by varying the amount of PKSA and lime added to each of the soil samples. The addition of 4% PKSA+ 6% lime, the addition of 4% PKSA + 4% lime, and the addition of 4% PKSA + 6% lime increased the California Bearing Ratio (CBR) to the highest values for L1, L2 and L3 from 8.20%. It was concluded that PKSA can be a suitable complement for lime stabilization in lateritic soil.

Origin of C. latifolia and C. aurantiifolia triploid limes: the preferential disomic inheritance of doubled-diploid 'Mexican' lime is consistent with an interploid hybridization hypothesis.

Science.gov (United States)

Rouiss, H; Bakry, F; Froelicher, Y; Navarro, L; Aleza, P; Ollitrault, P

2018-03-05

Two main types of triploid limes are produced worldwide. The 'Tahiti' lime type (Citrus latifolia) is predominant, while the 'Tanepao' type (C. aurantiifolia) is produced to a lesser extent. Both types result from natural interspecific hybridization involving a diploid gamete of C. aurantiifolia 'Mexican' lime type (itself a direct interspecific C. micrantha × C. medica hybrid). The meiotic behaviour of a doubled-diploid 'Mexican' lime, the interspecific micrantha/medica recombination and the resulting diploid gamete structures were analysed to investigate the possibility that 'Tahiti' and 'Tanepao' varieties are derived from natural interploid hybridization. A population of 85 tetraploid hybrids was established between a doubled-diploid clementine and a doubled-diploid 'Mexican' lime and used to infer the genotypes of 'Mexican' lime diploid gametes. Meiotic behaviour was studied through combined segregation analysis of 35 simple sequenbce repeat (SSR) and single nucleotide polymorphismn (SNP) markers covering the nine citrus chromosomes and cytogenetic studies. It was supplemented by pollen viability assessment. Pollen viability of the doubled-diploid Mexican lime (64 %) was much higher than that of the diploid. On average, 65 % of the chromosomes paired as bivalents and 31.4 % as tetravalents. Parental heterozygosity restitution ranged from 83 to 99 %. Disomic inheritance with high preferential pairing values was deduced for three chromosomes. Intermediate inheritances, with disomic trend, were found for five chromosomes, and an intermediate inheritance was observed for one chromosome. The average effective interspecific recombination rate was low (1.2 cM Mb-1). The doubled-diploid 'Mexican' lime had predominantly disomic segregation, producing interspecific diploid gamete structures with high C. medica/C. micrantha heterozygosity, compatible with the phylogenomic structures of triploid C. latifolia and C. aurantiifolia varieties. This disomic trend limits

Elemental analysis of Taiwanese areca nut and limes with INAA

International Nuclear Information System (INIS)

Wei, Y.Y.; Chung, C.

1997-01-01

The popular areca nuts were sampled and their stuffed white and red lime were collected simultaneously from four marketplaces in Taiwan in different growing seasons. Samples of areca nut were treated via homogenizer prior to freeze drying, about 100-150 mg each of the areca nut and lime were packed into PE bag. Samples were irradiated with neutron flux about 10 12 n x cm -2 x s -1 . A total of 17, 18, and 13 elements was analyzed with INAA for white lime, red lime, and areca nut, respectively. The results indicated that Ca have the highest concentration in both limes. Most elements in collected samples have wide range of concentrations among different seasons and marketplaces. It is suggested that the elemental concentration of areca nut and limes exists in divergence originated from various farms in Taiwan. In addition, four elements of Ca, Fe, Mg, and Sc are probably overtaken by persons having chewing habit of areca nut and their effects on oral cancer are discussed. (author)

Economic evaluation of the industrial solar production of lime

International Nuclear Information System (INIS)

Meier, Anton; Gremaud, Nicolas; Steinfeld, Aldo

2005-01-01

The use of concentrated solar energy in place of fossil fuels for driving the endothermic calcination reaction CaCO 3 → CaO + CO 2 at above 1300 K has the potential of reducing CO 2 emissions by 20% in a state-of-the-art lime plant and up to 40% in a conventional cement plant. An economic assessment for an industrial solar calcination plant with 25 MW th solar input indicates that the cost of solar produced lime ranges between 128 and 157 $/t, about twice the current selling price of conventional lime. The solar production of high purity lime for special sectors in the chemical and pharmaceutical industry might be competitive with conventional fossil fuel based calcination processes at current fuel prices

Formation of fine crystalline dolomites in lacustrine carbonates of the Eocene Sikou Depression, Bohai Bay Basin, East China

Directory of Open Access Journals (Sweden)

Yong-Qiang Yang

2016-11-01

Full Text Available Abstract The genesis of the fine crystalline dolomites that exhibit good to excellent reservoir properties in the upper fourth member of the Eocene Shahejie Formation (Es 4 s around the Sikou Sag, Bohai Bay Basin, is uncertain. This paper investigates the formation mechanisms of this fine crystalline dolomite using XRD, SEM, thin section analysis and geochemical data. The stratigraphy of the Sikou lacustrine carbonate is dominated by the repetition of metre-scale, high-frequency deposition cycles, and the amount of dolomite within a cycle increases upward from the cycle bottom. These dolomite crystals are 2–30 μm in length, subhedral to anhedral in shape and typically replace both grains and matrix. They also occur as rim cement and have thin lamellae within ooid cortices. Textural relations indicate that the dolomite predates equant sparry calcite cement and coarse calcite cement. The Sr concentrations of dolomites range from 900 to 1200 ppm. Dolomite δ18O values (−11.3 to −8.2 ‰ PDB are depleted relative to calcite mudstone (−8.3 to −5.4 ‰ PDB that precipitated from lake water, while δ13C values (0.06–1.74 ‰ PDB are within the normal range of calcite mudstone values (−2.13 to 1.99 ‰ PDB. High 87Sr/86Sr values (0.710210–0.710844 indicate that amounts of Ca2+ and Mg2+ have been derived from the chemical weathering of Palaeozoic carbonate bedrocks. The high strontium concentration indicates that hypersaline conditions were maintained during the formation of the dolomites and that the dolomites were formed by the replacement of precursor calcite or by direct precipitation.

Remagnetization and Cementation of Unconsolidated Sediments in the Mallik 5L-38 Well (Canadian Arctic) by Solute Exclusion During Gas Hydrate Formation

Science.gov (United States)

Hamilton, T. S.; Enkin, R. J.; Esteban, L.

2007-05-01

Bulk magnetic properties provide a sensitive measure of sedimentary diagenesis related to the stability and growth of gas hydrates. The deposit at Mallik (Mackenzie Delta, Canadian Arctic) occurs in unconsolidated Tertiary sands, but is absent in interstratified silt layers. A detailed sampling of the JAPEX/JNOC/GSC Mallik 5L-38 core tested the use of magnetic properties for detecting diagenetic changes related to the hydrate. Petrographic studies reveal that the sands are well sorted and clean, with quartz > chert >> muscovite and little fines content. Excepting a few rare bands of indurated dolomite in the midst of the gas hydrate zone, there is little or no cementation in the sands. Detrital magnetite is the dominant magnetic mineral, comprising up to a few percent of the sand grain population. In contrast, the muddier layers have a somewhat different detrital grain composition, richer in lithic (sedimentary and metamorphic) grains, feldspar, and clays. They are extensively diagenetically altered (to as much as 30- 40%) and cemented with carbonates, clays, chlorite and the iron sulphide greigite (the dominant magnetic mineral). The greigite is recognized by its isotropic creamy-white reflectance, cubic to prismatic habit, and characteristic tarnish to faintly bluish bireflectant mackinawite. Habits range from disseminated cubes and colliform masses to inflationary massive sulphide veins and clots. Rare detrital grains of magnetite were observed among the silt grains, but never in a reaction relationship or overgrown. Instead the greigite has nucleated separately, in tensional fractures and granular masses up to 4 mm across. In this particular sediment sequence, being so quartz and chert rich, there is insufficient local source for the introduced cements (calcite, dolomite, greigite, clays, jarosite), so ions must have been introduced by fluid flow. Magnetic studies reveal a bi-modal character related to the lithology (sands versus silts) and their magnetic

Reconsideration on Hydration of Sodium Ion: From Micro-Hydration to Bulk Hydration

Science.gov (United States)

Yongquan, Zhou; Chunhui, Fang; Yan, Fang; Fayan, Zhu; Haiwen, Ge; Hongyan, Liu

2017-12-01

Micro hydration structures of the sodium ion, [Na(H2O) n ]+, n = 1-12, were probed by density functional theory (DFT) at B3LYP/aug-cc-pVDZ level in both gaseous and aqueous phase. The predicted equilibrium sodium-oxygen distance of 0.240 nm at the present level of theory. The four-, five- and six-coordinated cluster can transform from each other at the ambient condition. The analysis of the successive water binding energy and natural charge population (NBO) on Na+ clearly shows that the influence of Na+ on the surrounding water molecules goes beyond the first hydration shell with the hydration number of 6. The Car-Parrinello molecular dynamic simulation shows that only the first hydration sphere can be found, and the hydration number of Na+ is 5.2 and the hydration distance ( r Na-O) is 0.235 nm. All our simulations mentioned in the present paper show an excellent agreement with the diffraction result from X-ray scattering study.

Managing ecosystems without prior knowledge: pathological outcomes of lake liming

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David G. Angeler

2017-12-01

Full Text Available Management actions often need to be taken in the absence of ecological information to mitigate the impact of pressing environmental problems. Managers counteracted the detrimental effects of cultural acidification on aquatic ecosystems during the industrial era using liming to salvage biodiversity and ecosystem services. However, historical contingencies, i.e., whether lakes were naturally acidic or degraded because of acidification, were largely unknown and therefore not accounted for in management. It is uncertain whether liming outcomes had a potentially detrimental effect on naturally acidic lakes. Evidence from paleolimnological reconstructions allowed us to analyze community structure in limed acidified and naturally acidic lakes, and acidified and circumneutral references. We analyzed community structure of phytoplankton, zooplankton, macroinvertebrates (littoral, sublittoral, profundal, and fish between 2000 and 2004. Naturally acidic limed lakes formed communities that were not representative of the other lake types. The occurrence of fish species relevant for ecosystem service provisioning (fisheries potential in naturally acidic limed lakes were confounded by biogeographical factors. In addition, sustained changes in water quality were conducive to harmful algal blooms. This highlights a pathological outcome of liming lakes when their naturally acidic conditions are not accounted for. Because liming is an important social-ecological system, sustained ecological change of lakes might incur undesired costs for societies in the long term.

Magnesium production from Asian Abe-Gram dolomite in pidgeon-type reactor

International Nuclear Information System (INIS)

Mehrabi, B.; Abdellatifi, M.; Masoudi, F.

2011-01-01

Ore mineral characterization and various experimental test work were carried out on Asian Abe-Garm dolomite, Qazvin province, Iran. The test work consisted of calcining, chemical characterization, LOI determination, and reduction tests on the calcined dolomite (doloma), using Semnan ferrosilicon. Calcining of dolomite sample was carried out at about 1400 d egree C in order to remove the contained CO 2 , moisture, and other easily volatilised impurities. The doloma was milled, thoroughly mixed with 21 p ercent S emnan ferrosilicon and briquetted in hand press applying 30 MPa pressure. The briquettes were heated at 1125-1150 d egree C and 500 Pa in a Pidgeon-type tube reactor for 10-12 hours to extract the magnesium. Ferrosilicon addition, relative to doloma, was determined based on the chemical analysis of the two reactants using Mintek's Pyrosim software package. Magnesium extraction calculated as 77.97 p ercent a nd Mg purity of 96.35 p ercent . The level of major impurities in the produced magnesium crown is similar to those in the crude metal production.

Effects of Metal Ions on the Flotation of Apatite, Dolomite and Quartz

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Yaoyang Ruan

2018-04-01

Full Text Available The effects of Ca2+, Mg2+, Al3+, and Fe3+ on the flotation behaviors of apatite, dolomite and quartz were investigated through a micro-flotation test, and the influence of calcium ions on the flotation of these minerals was further elucidated by solution chemistry study, zeta potential measurement, and X-ray photoelectron spectroscopy (XPS analyses. The results indicate that an appropriate amount of Ca2+ and Mg2+ can improve the floatability of apatite but had a negligible effect on the flotation performance of dolomite, whereas Al3+, Fe3+, and excessive amounts of Ca2+ decreased the recovery of apatite and dolomite. The studied metal cations can activate quartz at a particular pH. It can be inferred from solution chemistry and zeta potential measurement that the influence of metal ions on the flotation of different minerals should be attributed to the adsorption of various hydrolysis species on the mineral surfaces. XPS analyses reveal that calcium ions can enhance the adsorption of anionic collector on apatite and quartz surfaces, and there are no apparent changes to be observed on the surface of dolomite in the absence and presence of calcium ions at a concentration of 2.5 × 10−3 M, which was in good agreement with the micro-flotation results.

Using enteric pathogens to assess sources of fecal contamination in the Silurian Dolomite Aquifer: Preliminary results

Science.gov (United States)

Muldoon, Maureen A; Borchardt, Mark A.; Spencer, Susan K.; Hunt, Randall J.; Owens, David

2018-01-01

The fractured Silurian dolomite aquifer is an important, but vulnerable, source of drinking water in northeast Wisconsin (Sherrill in Geology and ground water in Door County, Wisconsin, with emphasis on contamination potential in the Silurian dolomite, 1978; Bradbury and Muldoon in Hydrogeology and groundwater monitoring of fractured dolomite in the Upper Door Priority Watershed, Door County, Wisconsin, 1992; Muldoon and Bradbury in Assessing seasonal variations in recharge and water quality in the Silurian aquifer in areas with thicker soil cover. p 45, 2010). Areas underlain by the Silurian dolomite aquifer are extremely vulnerable to groundwater contamination from various land-use activities, especially the disposal of human wastewater and dairy manure. Currently there is no consensus as to which source of wastewater generates the greater impact to the aquifer.

Water Utility Lime Sludge Reuse – An Environmental Sorbent ...

Science.gov (United States)

Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up included a simulated flue gas preparation unit, a lab-scale wet scrubber, and a mercury analyzer system. The influent mercury concentration was based on a range from 22 surveyed power plants. The reactivity of the lime sludge sample for acid neutralization was determined using a method similar to method ASTM C1318-95. Similar experiments were conducted using reagent calcium carbonate and calcium sulfate to obtain baseline data for comparing with the lime sludge test results. The project also evaluated the techno-economic feasibility and sustainable benefits of reusing lime softening sludge. If implemented on a large scale, this transformative approach for recycling waste materials from water treatment utilities at power generation utilities for environmental cleanup can save both water and power utilities millions of dollars. Huge amounts of lime sludge waste, generated from hundreds of water treatment utilities across the U.S., is currently disposed in landfills. This project evaluated a sustainable and economically-attractive approach to the use of lime sludge waste as a valuable resource for power generation utilities.

Effect of gamma radiation on chemical composition and storability of lime RTS

International Nuclear Information System (INIS)

Pandey, S.K.; Bisen, A.; Dwivedi, V.

2008-01-01

In the present investigation, the RTS was irradiated with different doses of gamma radiation to study their effect on chemical composition and storability of lime RTS and vitamin C content only was influenced significantly by 50 Gy gamma radiation during storage (16 days) without adversely affecting the quality of lime fruits, whereas, under control and higher doses of gamma radiation, the quality of lime RTS was deteriorated. The irradiation of lime with 50 Gy gamma radiation may be useful for extending storability of lime of RTS and stabilizing the market demand. (author)

Influence of lime juice on the severity of sickle cell anemia.

Science.gov (United States)

Adegoke, Samuel Ademola; Shehu, Umar Abdullahi; Mohammed, Lasisi Oluwafemi; Sanusi, Yunusa; Oyelami, Oyeku Akibu

2013-06-01

The pain in sickle cell anemia (SCA) is often triggered by dehydration, acidosis, and fever that are usually due to malaria. Intake of lime juice was recently demonstrated to facilitate clearance of the malaria parasite. It was therefore sought to determine whether regular intake of lime juice will ameliorate crisis, especially recurrent bone pain. In this preliminary, open-labeled, randomized study, the effects of lime juice on the clinical and some laboratory characteristics of children with SCA were tested. Among the 113 children with SCA studied in two hospitals, the 58 receiving lime treatment had lower rates of significant painful episodes than the 55 without lime (37 versus 83 crises in 6 months, and 0.64±0.11 versus 1.51±0.34 average rates per child, plime did not cause any significant side-effect. Regular intake of lime juice may be of great therapeutic and nutritional relevance in children with SCA.

Experimental study of silty clay stabilization with cement and lime in multan, pakistan

International Nuclear Information System (INIS)

Sultan, T.

2014-01-01

Stabilization is valuable substitute for advancing the soil characteristics. The engineering features gained after stabilization differs broadly owing to non-uniformity in constitutions of soil. This study describes an assessment of cement and lime additives for advancing soils ventures. The effectiveness of lime and cement stabilization on geotechnical characteristics of the in situ soil has also been described in the paper. The additives like cement and lime were added in different dosage rates to examine the change in properties of the in situ soil. Cement addition caused an increase in unconfined compression strength (UCS) throughout from 4% to 16% of cement. Moreover, it has been observed that by adding lime, the early strength of clay increases up to 6% of lime but for long term strength i.e. 28 days maximum strengths is achieved for 4% of lime. It also confirms that with more percentage of lime and longer duration of curing, it expands. In addition to the strength behavior of samples at various percentages of cement and lime, the deflection at failure point was also examined. In order to make a straight comparison, both cement and lime stabilized soils were also tested in laboratory. Generally, the performance of Portland cement-stabilized soils was advanced to lime in the experiments performed. (author)

Development of a three-dimensional CFD model for rotary lime kilns

Energy Technology Data Exchange (ETDEWEB)

Lixin Tao; Blom, Roger (FS Dynamics Sweden AB, Goeteborg (Sweden)); Nordgren, Daniel (Innventia, Stockholm (Sweden))

2010-11-15

In the calcium loop of the recovery cycle in a Kraft process of pulp and paper production, rotary lime kilns are used to convert the lime mud, mainly CaCO3, back to quick lime, CaO, for re-use in the causticizing process. The lime kilns are one of the major energy consumption devices for paper and pulp industry. Because of the rising oil price and new emission limits, the pulp mills have been forced to look for alternative fuels for their lime kilns. One interesting alternative to oil, often easily available at pulp mills, is biofuels such as sawdust and bark. However the practical kiln operation often encounters some difficulties because of the uncertainties around the biofuel impact on the lime kiln performance. A deeper understanding of the flame characteristics is required when shifting from oil to biofuels. Fortunately recent advances in modern Computational Fluid Dynamics, CFD, have provided the possibility to study and predict the detailed flame characteristics regarding the lime kiln performance. In this project a three-dimensional CFD model for rotary lime kilns has been developed. To simulate a rotary lime kiln the developed CFD model integrates the three essential sub-models, i.e. the freeboard hot flow model, the lime bed model and the rotating refractory wall model and it is developed based on the modern CFD package: FLUENT which is commercially available on the market. The numerical simulations using the developed CFD model have been performed for three selected kiln operations fired with three different fuel mixtures. The predicted results from the CFD modelling are presented and discussed in order to compare the impacts on the kiln performance due to the different firing conditions. During the development, the lime kiln at the Soedra Cell Moensteraas mill has been used as reference kiln. To validate the CFD model, in-plant measurements were carried out in the Moensteraas lime kiln during an experiment campaign. The results obtained from the

Intermediate-scale tests of sodium interactions with calcite and dolomite aggregate concretes

International Nuclear Information System (INIS)

Randich, E.; Acton, R.U.

1983-09-01

Two intermediate-scale tests were performed to compare the behavior of calcite and dolomite aggregate concretes when attacked by molten sodium. The tests were performed as part of an interlaboratory comparison between Sandia National Laboratories and Hanford Engineering Development Laboratories. Results of the tests at Sandia National Laboratories are reported here. The results show that both concretes exhibit similar exothermic reactions with molten sodium. The large difference in reaction vigor suggested by thermodynamic considerations of CO 2 release from calcite and dolomite was not realized. Penetration rates of 1.4 to 1.7 mm/min were observed for short periods of time with reaction zone temperatures in excess of 800 0 C during the energetic attack. The penetration was not uniform over the entire sodium-concrete contact area. Rapid attack may be localized due to inhomogeneities in the concrete. The chemical reaction zone is less then one cm thick for the calcite concrete but is about seven cm thick for the dolomite concrete

Soybean root growth and crop yield in reponse to liming at the beginning of a no-tillage system

Directory of Open Access Journals (Sweden)

Edson Campanhola Bortoluzzi

2014-02-01

Full Text Available Analyzing the soil near crop roots may reveal limitations to growth and yield even in a no-tillage system. The purpose of the present study was to relate the chemical and physical properties of soil under a no-tillage system to soybean root growth and plant yield after five years of use of different types of limestone and forms of application. A clayey Oxisol received application of dolomitic and calcitic limestones and their 1:1 combination in two forms: surface application, maintained on the soil surface; and incorporated, applied on the surface and incorporated mechanically. Soil physical properties (resistance to mechanical penetration, soil bulk density and soil aggregation, soil chemical properties (pH, exchangeable cations, H+Al, and cation exchange capacity and plant parameters (root growth system, soybean grain yield, and oat dry matter production were evaluated five years after setting up the experiment. Incorporation of lime neutralized exchangeable Al up to a depth of 20 cm without affecting the soil physical properties. The soybean root system reached depths of 40 cm or more with incorporated limestone, increasing grain yield an average of 31 % in relation to surface application, which limited the effect of lime up to a depth of 5 cm and root growth up to 20 cm. It was concluded that incorporation of limestone at the beginning of a no-tillage system ensures a favorable environment for root growth and soybean yield, while this intervention does not show long-term effects on soil physical properties under no-tillage. This suggests that there is resilience in the physical properties evaluated.

Effects of experimental acidification on mobilisation of metals from sediments of limed and non-limed lakes

International Nuclear Information System (INIS)

Waellstedt, Teresia; Borg, Hans

2003-01-01

In order to study the influence of pH on the mobilisation of metals from lake sediments, intact sediment cores with overlying water were sampled from one lime treated lake and one acidified lake. The overlying water of two cores from each lake was successively acidified to pH 4.2 over a period of 3 months. In the acid treated samples from the limed lake, the initial concentrations of Al, Cd, Mn, Pb and Zn in the overlying water were generally lower and the final concentrations were higher than in the acid treated samples from the acidified lake. The labile inorganic fraction of Al (Al i ) was increasingly dominating as pH decreased. Redox potential and pH in the sediment indicated that the upper two centimetres were involved in the exchange reactions. The experiment showed that mobilisation of metals from sediments can occur and the results indicated that mobilisation could contribute to increased concentrations of metals in lake water during reacidification of formerly lime treated lakes. - Reacidification leads to mobilisation of metals from lake sediments

Hydrate-CASM for modeling Methane Hydrate-Bearing Sediments

Science.gov (United States)

De La Fuente Ruiz, M.; Vaunat, J.; Marin Moreno, H.

2017-12-01

A clear understanding of the geomechanical behavior of methane hydrate-bearing sediments (MHBS) is crucial to assess the stability of the seafloor and submarine infrastructures to human and natural loading changes. Here we present the Hydrate-CASM, a new elastoplastic constitutive model to predict the geomechanical behavior of MHBS. Our model employs the critical state model CASM (Clay and Sand Model) because of its flexibility in describing the shape of the yield surface and its proven ability to predict the mechanical behavior of sands, the most commercially viable hydrate reservoirs. The model considers MHBS as a deformable elastoplastic continuum, and hydrate-related changes in the stress-strain behavior are predicted by a densification mechanism. The densification attributes the mechanical contribution of hydrate to; a reduction of the available void ratio; a decrease of the swelling line slope; and an increase of the volumetric yield stress. It is described by experimentally derived physical parameters except from the swelling slope coefficient that requires empirical calibration. The Hydrate-CASM is validated against published triaxial laboratory tests performed at different confinement stresses, hydrate saturations, and hydrate morphologies. During the validation, we focused on capturing the mechanical behavior of the host sediment and consider perturbations of the sediment's mechanical properties that could result from the sample preparation. Our model successfully captures the experimentally observed influence of hydrate saturation in the magnitude and trend of the stiffness, shear strength, and dilatancy of MHBS. Hence, we propose that hydrate-related densification changes might be a major factor controlling the geomechanical response of MHBS.

Plasticity, Swell-Shrink, and Microstructure of Phosphogypsum Admixed Lime Stabilized Expansive Soil

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Jijo James

2016-01-01

Full Text Available The study involved utilization of an industrial waste, Phosphogypsum (PG, as an additive to lime stabilization of an expansive soil. Three lime dosages, namely, initial consumption of lime (ICL, optimum lime content (OLC, and less than ICL (LICL, were identified for the soil under study for stabilizing the soil. Along with lime, varying doses of PG were added to the soil for stabilization. The effect of stabilization was studied by performing index tests, namely, liquid limit, plastic limit, shrinkage limit, and free swell test, on pulverized remains of failed unconfined compression test specimens. The samples were also subjected to a microstructural study by means of scanning electron microscope. Addition of PG to lime resulted in improvement in the plasticity and swell-shrink characteristics. The microstructural study revealed the formation of a dense compact mass of stabilized soil.

EPR, UV-Visible, and Near-Infrared Spectroscopic Characterization of Dolomite

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S. Lakshmi Reddy

2008-01-01

Full Text Available Dolomite mineral samples having white and light green colors of Indian origin have been characterized by EPR, optical, and NIR spectroscopy. The optical spectrum exhibits a number of electronic bands due to presence of Fe(III ions in the mineral. From EPR studies, the parameters of g for Fe(III and g,A, and D for Mn(II are evaluated and the data confirm that the ions are in distorted octahedron. Optical absorption studies reveal that Fe(III is in distorted octahedron. The bands in NIR spectra are due to the overtones and combinations of water molecules. Thus EPR and optical absorption spectral studies have proven useful for the study of the solid state chemistry of dolomite.

Kaffir lime leaves extract inhibits biofilm formation by Streptococcus mutans.

Science.gov (United States)

Kooltheat, Nateelak; Kamuthachad, Ludthawun; Anthapanya, Methinee; Samakchan, Natthapon; Sranujit, Rungnapa Pankla; Potup, Pachuen; Ferrante, Antonio; Usuwanthim, Kanchana

2016-04-01

Although kaffir lime has been reported to exhibit antioxidant and antileukemic activity, little is known about the antimicrobial effect of kaffir lime extract. Because Streptococcus mutans has been known to cause biofilm formation, it has been considered the most important causative pathogen of dental caries. Thus, the effective control of its effects on the oral biofilm is the key to the prevention of dental caries. The aims of the present study were to investigate the effect of kaffir lime leaves extract on biofilm formation and its antibacterial activity on S. mutans. We examined the effect of kaffir lime leaves extract on growth and biofilm formation of S. mutans. For the investigation we used a kaffir lime extract with high phenolic content. The minimum inhibitory concentration of the extract was determined by broth microdilution assay. The inhibitory effect of the test substances on biofilm formation was also investigated by biofilm formation assay and qRT-PCR of biofilm formation-associated genes. Kaffir lime leaves extract inhibits the growth of S. mutans, corresponding to the activity of an antibiotic, ampicillin. Formation of biofilm by S. mutans was also inhibited by the extract. These results were confirmed by the down-regulation of genes associated with the biofilm formation. The findings highlight the ability of kaffir lime leaves extract to inhibit S. mutans activity, which may be beneficial in the prevention of biofilm formation on dental surface, reducing dental plaque and decreasing the chance of dental carries. Copyright © 2016 Elsevier Inc. All rights reserved.

Liming the acid lake Hovvatn, Norway: a whole-ecosystem study

Energy Technology Data Exchange (ETDEWEB)

Raddum, G G; Brettum, P; Matzow, D; Nilssen, J P; Skov, A; Sveaelv, T; Wright, R F

1986-12-01

Hovvatn, a 1 sq. km. chronically-acidified lake in southernmost Norway, was treated with 200 tonne of powdered limestone in March 1981. An additional 40 tonne were added to a 0.046 sq km pond (Pollen) draining into Hovvatn. The lakes were stocked with brown trout in June 1981 and in each subsequent year. At ice-out pH rose from 4.4 to 6.3 (Hovvatn) and 7.5 (Pollen), Ca and alkalinity increased, and total Al decreased by 120 ..mu..g/l. None of the other major ions exhibited significant changes in concentration. Total organic C and P increased after liming. The phytoplankton community was dominated by chrysophytes and did not change significantly following liming. The zooplankton community was typical of acid lakes prior to liming. There was a clear succession in species dominance following treatment, although no new species immigrated to the lakes. Zoobenthos changed from a community characterized by low abundance and reduced number of species to increased abundance of oligochaetes, mayflies and chironomids. Hovvatn and Pollen were barren of fish prior to stocking. The stocked fish showed remarkably high growth rate during the first years. Liming apparently improved conditions for zoobenthos, enhancing the processing of fine detritus which in turn resulted in elevated levels of TOC and P in the lakewaters during the first year after liming. The oligotrophication process typical of acid lakes was temporarily reversed by liming. The interactions between groups of organisms in Hovvatn and Pollen indicates that many years are required before a new steady-state can be attained following liming. 61 references.

Insights into the dolomitization process and porosity modification in sucrosic dolostones, Avon Park Formation (Middle Eocene), East-Central Florida, U.S.A.

KAUST Repository

Maliva,, Robert G.

2011-03-01

The Avon Park Formation (middle Eocene) in central Florida, U.S.A., contains shallow-water carbonates that have been replaced by dolomite to varying degrees, ranging from partially replaced limestones, to highly porous sucrosic dolostones, to, less commonly, low-porosity dense dolostones. The relationships between dolomitization and porosity and permeability were studied focusing on three 305-m-long cores taken in the City of Daytona Beach. Stable-isotope data from pure dolostones (mean δ 18O = +3.91% V-PDB) indicate dolomite precipitation in Eocene penesaline pore waters, which would be expected to have been at or above saturation with respect to calcite. Nuclear magnetic log-derived porosity and permeability data indicate that dolomitization did not materially change total porosity values at the bed and formation scale, but did result in a general increase in pore size and an associated substantial increase in permeability compared to limestone precursors. Dolomitization differentially affects the porosity and permeability of carbonate strata on the scale of individual crystals, beds, and formations. At the crystal scale, dolomitization occurs in a volume-for-volume manner in which the space occupied by the former porous calcium carbonate is replaced by a solid dolomite crystal with an associated reduction in porosity. Dolomite crystal precipitation was principally responsible for calcite dissolution both at the actual site of dolomite crystal growth and in the adjoining rock mass. Carbonate is passively scavenged from the formation, which results in no significant porosity change at the formation scale. Moldic pores after allochems formed mainly in beds that experienced high degrees of dolomitization, which demonstrates the intimate association of the dolomitization process with carbonate dissolution. The model of force of crystallization-controlled replacement provides a plausible explanation for key observations concerning the dolomitization process in the

Insights into the dolomitization process and porosity modification in sucrosic dolostones, Avon Park Formation (Middle Eocene), East-Central Florida, U.S.A.

KAUST Repository

Maliva,, Robert G.; Budd, David A.; Clayton, Edward A.; Missimer, Thomas M.; Dickson, John Anthony D

2011-01-01

The Avon Park Formation (middle Eocene) in central Florida, U.S.A., contains shallow-water carbonates that have been replaced by dolomite to varying degrees, ranging from partially replaced limestones, to highly porous sucrosic dolostones, to, less commonly, low-porosity dense dolostones. The relationships between dolomitization and porosity and permeability were studied focusing on three 305-m-long cores taken in the City of Daytona Beach. Stable-isotope data from pure dolostones (mean δ 18O = +3.91% V-PDB) indicate dolomite precipitation in Eocene penesaline pore waters, which would be expected to have been at or above saturation with respect to calcite. Nuclear magnetic log-derived porosity and permeability data indicate that dolomitization did not materially change total porosity values at the bed and formation scale, but did result in a general increase in pore size and an associated substantial increase in permeability compared to limestone precursors. Dolomitization differentially affects the porosity and permeability of carbonate strata on the scale of individual crystals, beds, and formations. At the crystal scale, dolomitization occurs in a volume-for-volume manner in which the space occupied by the former porous calcium carbonate is replaced by a solid dolomite crystal with an associated reduction in porosity. Dolomite crystal precipitation was principally responsible for calcite dissolution both at the actual site of dolomite crystal growth and in the adjoining rock mass. Carbonate is passively scavenged from the formation, which results in no significant porosity change at the formation scale. Moldic pores after allochems formed mainly in beds that experienced high degrees of dolomitization, which demonstrates the intimate association of the dolomitization process with carbonate dissolution. The model of force of crystallization-controlled replacement provides a plausible explanation for key observations concerning the dolomitization process in the

Obtención de silicatos de calcio utilizando el método de precipitación controlada

OpenAIRE

Rodríguez-Páez, J. E.; Ahumada, L. M.; Bustamante, J. M.; Ruiz de Murgueitio, J.

2005-01-01

Calcium silicate hydrates are compounds of SiO2 – CaO – H2O system. These materials are used to make lime-sand bricks concretes, or “cellular concretes”, lime-flint brices and as fillers in rubber, paint and plastic products industries, among others. Undoubtedly, the tobermoritas is the most interesting group given its important role in concrete hydration: hydrated calcium silicate (C – S- H) is the main concrete hydration product and its primary bounding phase. The hydrothermal method is the...

Dolomitization in the diagenetic history of the Štramberg limestones

Czech Academy of Sciences Publication Activity Database

Lintnerová, O.; Knietl, M.; Reháková, D.; Skupien, P.; Vašíček, Zdeněk

2008-01-01

Roč. 34, 3/1 (2008), s. 191-192 ISSN 0138-0974 Institutional research plan: CEZ:AV0Z30860518 Keywords : Štramberk Limestone * dolomitization * dedolomitization Subject RIV: DB - Geology ; Mineralogy

Experimental observation and numerical simulation of permeability changes in dolomite at CO2 sequestration conditions

Science.gov (United States)

Tutolo, B. M.; Luhmann, A. J.; Kong, X.; Saar, M. O.; Seyfried, W. E.

2013-12-01

Injecting surface temperature CO2 into geothermally warm reservoirs for geologic storage or energy production may result in depressed temperature near the injection well and thermal gradients and mass transfer along flow paths leading away from the well. Thermal gradients are particularly important to consider in reservoirs containing carbonate minerals, which are more soluble at lower temperatures, as well as in CO2-based geothermal energy reservoirs where lowering heat exchanger rejection temperatures increases efficiency. Additionally, equilibrating a fluid with cation-donating silicates near a low-temperature injection well and transporting the fluid to higher temperature may enhance the kinetics of mineral precipitation in such a way as to overcome the activation energy required for mineral trapping of CO2. We have investigated this process by subjecting a dolomite core to a 650-hour temperature series experiment in which the fluid was saturated with CO2 at high pressure (110-126 bars) and 21°C. This fluid was recirculated through the dolomite core, increasing permeability from 10-16 to 10-15.2 m2. Subsequently, the core temperature was raised to 50° C, and permeability decreased to 10-16.2 m2 after 289 hours, due to thermally-driven CO2 exsolution. Increasing core temperature to 100°C for the final 145 hours of the experiment caused dolomite to precipitate, which, together with further CO2 exsolution, decreased permeability to 10-16.4 m2. Post-experiment x-ray computed tomography and scanning electron microscope imagery of the dolomite core reveals abundant matrix dissolution and enlargement of flow paths at low temperatures, and subsequent filling-in of the passages at elevated temperature by dolomite. To place this experiment within the broader context of geologic CO2 sequestration, we designed and utilized a reactive transport simulator that enables dynamic calculation of CO2 equilibrium constants and fugacity and activity coefficients by incorporating

Important geosites and parks in the UNESCO World Heritage Site of the Dolomites

International Nuclear Information System (INIS)

Nossing, L.; Forti, S.

2016-01-01

In the geological complexity of the south Tyrol, the Dolomites play a fundamental role, as they are now included in the UNESCO World Heritage (2009) because of their exceptional beauty and unique landscape, together with numerous scientific discoveries. The name of Dolomite comes from the famous mineral dolomite (double calcium magnesium carbonate) discovered by Déodat De Dolomieu in 1789. The dolomitic rocks constitute a large area of the Triassic mountains and many studies have contributed to the discovery of the fundamental stratotypes for the signature of the Permian/Triassic boundary. The steep walls of the Permian volcanic formations and the Sciliar Mountain have always been a great attraction for scientists from all over the world to study the open book of nature in the Dolomites. We will illustrate three sites: 1. The Bula Geotrail. A geological trail through one of the best-preserved sedimentary series in which we can observe one of the most important stratotypes to touch the Permian/Triassic boundary. 2. The Siusi-Alpe di Siusi Geological Trail. This trail starts just above the Permian/Triassic boundary and is characterized by some unique basaltic columnar formations and other significant outcrops of Lower and Medium Triassic. 3. The Bletterbach Geopark. In this sequence the stratotype, which represents the boundary, is a dark coloured continuous layer (organic matter) 5cm thick, and contains some paleobotanical evidence which is unique in the world. The preservation and added value of the natural and geological patrimony of a region through guided and documented trails are at the origin of a new kind of tourism: geotourism. The modern tourist is more and more interested and stimulated by getting to knowing nature in depth. The trails are the best instruments for scientific divulgation and education, allowing a better understanding of the landscape and stimulating new discoveries. (Author)

Important geosites and parks in the UNESCO World Heritage Site of the Dolomites

Energy Technology Data Exchange (ETDEWEB)

Nossing, L.; Forti, S.

2016-10-01

In the geological complexity of the south Tyrol, the Dolomites play a fundamental role, as they are now included in the UNESCO World Heritage (2009) because of their exceptional beauty and unique landscape, together with numerous scientific discoveries. The name of Dolomite comes from the famous mineral dolomite (double calcium magnesium carbonate) discovered by Déodat De Dolomieu in 1789. The dolomitic rocks constitute a large area of the Triassic mountains and many studies have contributed to the discovery of the fundamental stratotypes for the signature of the Permian/Triassic boundary. The steep walls of the Permian volcanic formations and the Sciliar Mountain have always been a great attraction for scientists from all over the world to study the open book of nature in the Dolomites. We will illustrate three sites: 1. The Bula Geotrail. A geological trail through one of the best-preserved sedimentary series in which we can observe one of the most important stratotypes to touch the Permian/Triassic boundary. 2. The Siusi-Alpe di Siusi Geological Trail. This trail starts just above the Permian/Triassic boundary and is characterized by some unique basaltic columnar formations and other significant outcrops of Lower and Medium Triassic. 3. The Bletterbach Geopark. In this sequence the stratotype, which represents the boundary, is a dark coloured continuous layer (organic matter) 5cm thick, and contains some paleobotanical evidence which is unique in the world. The preservation and added value of the natural and geological patrimony of a region through guided and documented trails are at the origin of a new kind of tourism: geotourism. The modern tourist is more and more interested and stimulated by getting to knowing nature in depth. The trails are the best instruments for scientific divulgation and education, allowing a better understanding of the landscape and stimulating new discoveries. (Author)

Paleoenvironmental and paleohydrochemical conditions of dolomite formation within a saline wetland in arid northwest Australia

Science.gov (United States)

Mather, Caroline C.; Skrzypek, Grzegorz; Dogramaci, Shawan; Grierson, Pauline F.

2018-04-01

Groundwater dolocrete occurring within the Fortescue Marsh, a large inland wetland in the Pilbara region of northwest Australia, has been investigated to provide paleoenvironmental and paleohydrological records and further the understanding of low temperature dolomite formation in terrestrial settings over the Quaternary Period. Two major phases of groundwater dolocrete formation are apparent from the presence of two distinct units of dolocrete, based on differences in depth, δ18O values and mineral composition. Group 1 (G1) occurs at depth 20-65 m b.g.l. (below ground level) and contains stoichiometric dolomite with δ18O values of -4.02-0.71‰. Group 2 (G2) is shallower (0-23 m b.g.l.), occurring close to the current groundwater level, and contains Ca-rich dolomite ± secondary calcite with a comparatively lower range of δ18O values (-7.74 and -6.03‰). Modelled δ18O values of paleogroundwater from which older G1 dolomite precipitated indicated highly saline source water, which had similar stable oxygen isotope compositions to relatively old brine groundwater within the Marsh, developed under a different hydroclimatic regime. The higher δ18O values suggest highly evaporitic conditions occurred at the Marsh, which may have been a playa lake to saline mud flat environment. In contrast, G2 dolomite precipitated from comparatively fresher water, and modelled δ18O values suggested formation from mixing between inflowing fresher groundwater with saline-brine groundwater within the Marsh. The δ18O values of the calcite indicates formation from brackish to saline groundwater, which suggests this process may be associated with coeval gypsum dissolution. In contrast to the modern hydrology of the Marsh, which is surface water dependent and driven by a flood and drought regime, past conditions conducive to dolomite precipitation suggest a groundwater dependent system, where shallow groundwaters were influenced by intensive evaporation.

Early diagenetic dolomitization and dedolomitization of Late Jurassic and earliest Cretaceous platform carbonates: A case study from the Jura Mountains (NW Switzerland, E France)

Science.gov (United States)

Rameil, Niels

2008-12-01

Early diagenetic dolomitization is a common feature in cyclic shallow-water carbonates throughout the geologic record. After their generation, dolomites may be subject to dedolomitization (re-calcification of dolomites), e.g. by contact with meteoric water during emersion. These patterns of dolomitization and subsequent dedolomitization frequently play a key role in unravelling the development and history of a carbonate platform. On the basis of excellent outcrops, detailed logging and sampling and integrating sedimentological work, high-resolution sequence stratigraphic interpretations, and isotope analyses (O, C), conceptual models on early diagenetic dolomitization and dedolomitization and their underlying mechanisms were developed for the Upper Jurassic / Lower Cretaceous Jura platform in north-western Switzerland and eastern France. Three different types of early diagenetic dolomites and two types of dedolomites were observed. Each is defined by a distinct petrographic/isotopic signature and a distinct spatial distribution pattern. Different types of dolomites are interpreted to have been formed by different mechanisms, such as shallow seepage reflux, evaporation on tidal flats, and microbially mediated selective dolomitization of burrows. Depending on the type of dolomite, sea water with normal marine to slightly enhanced salinities is proposed as dolomitizing fluid. Based on the data obtained, the main volume of dolomite was precipitated by a reflux mechanism that was switched on and off by high-frequency sea-level changes. It appears, however, that more than one dolomitization mechanism was active (pene)contemporaneously or several processes alternated in time. During early diagenesis, percolating meteoric waters obviously played an important role in the dedolomitization of carbonate rocks that underlie exposure surfaces. Cyclostratigraphic interpretation of the sedimentary succession allows for estimates on the timing of early diagenetic (de)dolomitization

Acid-base properties of a limed pyritic overburden during simulated weathering

Energy Technology Data Exchange (ETDEWEB)

Doolittle, J.J.; Hossner, L.R. [South Dakota State University, Brookings, SD (United States). Plant Science Dept.

1997-11-01

Surface-mine reclamation is often hindered by the formation of acid mine soil and acid mine drainage from FeS{sub 2} oxidation. Surface soils containing FeS{sub 2} are often treated with crushed limestone (predominately CaCO{sub 3}) to prevent aid minesoil formation. The main objective of this study was to evaluate the long-term effectiveness of liming pyritic minesoil to prevent the formation of acid minesoil and acid mine drainage. Pyritic minesoils that did not receive lime became acidic very rapidly and produced acidic leachate. Almost all of the FeS{sub 2} in this treatment oxidized during the first 200 d. The addition of lime at a rate of 25% of the theoretical acid-base account (ABA) significantly slowed FeS{sub 2} oxidation, but rapid oxidation ensued after the added lime was neutralized. Treatments receiving a liming rate of 50% ABA or greater remained neutral to alkaline throughout the study. Acid-base values and residual FeS{sub 2}-CO{sub 3} data, however, indicate that the lime was dissolving from the system faster than the FeS{sub 2} was oxidizing, and all the treatments would eventually become acidic. The results indicate that the liming of a pyritic overburden to an ABA of 125% is not a sustainable solution to preventing acid minesoil and acid mine drainage. 25 refs., 6 figs., 3 tabs.

Stabilization of expansive soil using bagasse ash & lime | Wubshet ...

African Journals Online (AJOL)

7-5 soil on the AASHTO classification was stabilized using 3% lime, 15% bagasse ash and 15% bagasse ash in combination with 3% lime by dry weight of the soil. The effect of the additives on the soil was investigated with respect to plastcity, ...

Model study of initial adsorption of SO{sub 2} on calcite and dolomite

Energy Technology Data Exchange (ETDEWEB)

Malaga-Starzec, Katarina; Panas, Itai; Lindqvist, Oliver

2004-01-30

The rate of calcareous stone degradation is to a significant extent controlled by their surface chemistry with SO{sub 2}. Initial surface sulphite is converted to a harmful gypsum upon, e.g. NO{sub 2} catalysed oxidation. However, it has been observed by scanning electron microscopy that the lateral distributions of gypsum crystals differ between calcitic and dolomitic marbles. The first-principles density functional theory is employed to understand the origin of these fundamentally different morphologies. Here, the stability differences of surface sulphite at calcite CaCO{sub 3} (s) and dolomite Ca{sub x}Mg{sub 1-x}CO{sub 3} (s) are determined. A qualitative difference in surface sulphite stability, favouring the former, is reported. This is taken to imply that calcitic micro-crystals embedded in a dolomitic matrix act as sinks in the surface sulphation process, controlled by SO{sub 2} diffusion. The subsequent formation of gypsum under such conditions will not require SO{sub 4}{sup 2-} (aq) ion transport. This explains the homogeneous distribution of gypsum observed on the calcitic micro-crystals in dolomite. In contrast, sulphation on purely calcitic marbles never reaches such high SO{sub 2} coverage. Rather, upon oxidation, SO{sub 4}{sup 2-} (aq) transport to nucleation centres, such as grain boundaries, is required for the growth of gypsum crystals.

Soil Stabilization with Lime for the Construction of Forest Roads

Directory of Open Access Journals (Sweden)

Reginaldo Sérgio Pereira

2018-02-01

Full Text Available ABSTRACT The mechanical performance of soil stabilization using lime to improve forest roads was assessed. This study was conducted with lateritic soil (LVAd30 using lime content of 2% in the municipality of Niquelândia, Goiás state, Brazil. Geotechnical tests of soil characterization, compaction, and mechanical strength were performed applying different compaction efforts and curing periods. The results showed that lime content significantly changed the mechanical performance of natural soil, increasing its mechanical strength and load-carrying capacity. Compaction effort and curing time provided different responses in the unconfined compressive strength (UCS and California Bearing Ratio (CBR tests. The best UCS value (786.59 kPa for the soil-lime mixture was achieved with modified compaction effort and curing time of 28 days. In the CBR test, soil-lime mixtures compacted at intermediate and modified efforts and cured for 28 days were considered for application as subbase material of flexible road pavements, being a promising alternative for use in layers of forest roads.

LIME EFFECTIVENESS OF SOME FERTILIZERS IN A TROPICAL ACID ALFISOL

Directory of Open Access Journals (Sweden)

Mercy Omogbohu Anetor

2007-11-01

Full Text Available Liming increases production costs and environmentally unfriendly. Effectiveness of crystalliser (CRYS, single super phosphate (SSP and organic fertilizer (OF for liming was evaluated by determining pH and phosphorus- (P- availability in an acid alfisol incubated with the amendments, Ca(OH2 being reference. Treatments were replicated thrice in completely randomised design. Un-amended soil remained acidic (pH 4.8 but liming raised pH (6.1-6.6, enhancing maximum (15.09-17.33 mg kg-1 P–release (un-amended having 4.24-7.09 mg P kg-1. Lime (L and L+P treatments resulted in maximum pH increases (7.0-7.2, decreasing with incubation. Fertilizer treatments also raised pH (5.0-5.5 for OF, CRYS or SSP; 5.6-5.8 for CRYS +SSP, CRYS+OF and OF+SSP relative to control (5.2. Acid soil infertility-ameliorating potential of CRYS and OF was revealed. They could be used multi-purposely as lime and P fertilizers by poor-resource farmers challenged by acid soil infertility factors.

Lime treatment of liquid waste containing heavy metals, radionuclides and organics

International Nuclear Information System (INIS)

DuPont, A.

1990-01-01

This paper reports on lime treatment of liquid waste containing heavy metals, radio nuclides and organics. Lime is wellknown for its use in softening drinking water the treatment of municipal wastewaters. It is becoming important in the treatment of industrial wastewater and liquid inorganic hazardous waste; however, there are many questions regarding the use of lime for the treatment of liquid hazardous waste

[Effects of Lime on Seedling Growth,Yield and Volatile Constituents of Atractylodes lancea].

Science.gov (United States)

Zhang, Yan; Miki, Sakurai; Chen, Mei-lan; Takeda, Xiuji; Zhao, Dong-yue; Kang, Li-ping; Guo, Lan-ping

2015-03-01

To investigate the effects of different amounts of lime on yield and quality of Atractylodes lancea, and to provide reference for the herb growing site soil improvement and self-poisoning ease. Add different gradients of lime, and then measure their growth targets, yield and four kinds of volatile constituents content(hinesol, atractylone, β-eudesmol and atractylodin). Volatile constituents yield per plant was calculated. Adding 160 g/m2 lime had a significant role in promoting the growth and yield of herb; Adding 80 g/m2 lime was conducive to the volatile constituents production, and adding lime decreased the atractylone and atractylodin content, while increased the hinesol and β-eudesmol content; Adding 160 g/m2 lime promoted the volatile constituents yield per plant. Adding lime plays a role of neutralize soil pH, antibacteria and prevention incognita, and has a certain degree of ease autotoxicity and obstacle,and then promotes the yield and volatile constituents production of Atractylodes lancea.

Lime helps establish crownvetch on coal-breaker refuse

Science.gov (United States)

Miroslaw M. Czapowskyj; Edward A. Sowa

1976-01-01

A study was begun in 1965 to determine the effect of lime fertilizer, and mulch on the establishment and growth of crownvetch crowns planted on anthracite coal-breaker refuse. After 7 years the lime application had by far the strongest effect. Both 2.5 and 5.0 tons per acre increased survival and ground cover manyfold, and both treatments were equally beneficial from...

Models for predicting the mass of lime fruits by some engineering properties.

Science.gov (United States)

Miraei Ashtiani, Seyed-Hassan; Baradaran Motie, Jalal; Emadi, Bagher; Aghkhani, Mohammad-Hosein

2014-11-01

Grading fruits based on mass is important in packaging and reduces the waste, also increases the marketing value of agricultural produce. The aim of this study was mass modeling of two major cultivars of Iranian limes based on engineering attributes. Models were classified into three: 1-Single and multiple variable regressions of lime mass and dimensional characteristics. 2-Single and multiple variable regressions of lime mass and projected areas. 3-Single regression of lime mass based on its actual volume and calculated volume assumed as ellipsoid and prolate spheroid shapes. All properties considered in the current study were found to be statistically significant (ρ lime based on minor diameter and first projected area are the most appropriate models in the first and the second classifications, respectively. In third classification, the best model was obtained on the basis of the prolate spheroid volume. It was finally concluded that the suitable grading system of lime mass is based on prolate spheroid volume.

Muddy and dolomitic rip-up clasts in Triassic fluvial sandstones: Origin and impact on potential reservoir properties (Argana Basin, Morocco)

Science.gov (United States)

Henares, Saturnina; Arribas, Jose; Cultrone, Giuseppe; Viseras, Cesar

2016-06-01

The significance of rip-up clasts as sandstone framework grains is frequently neglected in the literature being considered as accessory components in bulk sandstone composition. However, this study highlights the great value of muddy and dolomitic rip-up clast occurrence as: (a) information source about low preservation potential from floodplain deposits and (b) key element controlling host sandstone diagenetic evolution and thus ultimate reservoir quality. High-resolution petrographic analysis on Triassic fluvial sandstones from Argana Basin (T6 and T7/T8 units) highlights the significance of different types of rip-up clasts as intrabasinal framework components of continental sediments from arid climates. On the basis of their composition and ductility, three main types are distinguished: (a) muddy rip-up clasts, (b) dolomitic muddy rip-up clasts and (c) dolomite crystalline rip-up clasts. Spatial distribution of different types is strongly facies-related according to grain size. Origin of rip-up clasts is related to erosion of coeval phreatic dolocretes, in different development stages, and associated muddy floodplain sediments. Cloudy cores with abundant inclusions and clear outer rims of dolomite crystals suggest a first replacive and a subsequent displacive growth, respectively. Dolomite crystals are almost stoichiometric. This composition is very similar to that of early sandstone dolomite cement, supporting phreatic dolocretes as dolomite origin in both situations. Sandstone diagenesis is dominated by mechanical compaction and dolomite cementation. A direct correlation exists between: (1) muddy rip-up clast abundance and early reduction of primary porosity by compaction with irreversible loss of intergranular volume (IGV); and (2) occurrence of dolomitic rip-up clasts and dolomite cement nucleation in host sandstone, occluding adjacent pores but preserving IGV. Both processes affect reservoir quality by generation of vertical and 3D fluid flow baffles and

Characterization of historic lime mortars by neutron scattering and mercury porosimetry

International Nuclear Information System (INIS)

Zouridakis, N.; Stefanopoulos, K.L.; Treimer, W.

1999-01-01

Complete text of publication follows. Lime mortars were commonly used in building from ancient Greek times through to the beginning of the nineteenth century [1]. In the past few years, the increased interest in conservation and restoration of historic monuments requires a better knowledge of the structure and composition of lime mortars resulting from the various additives, as well as the preparation technique each time used. Lime mortars from ancient Greek monuments have been dated by using the radiocarbon method [2]. Furthermore, a wide selection of lime mortars from known historic periods and monuments in Greece has been examined by mercury porosimetry. It was found that their structure depends on the utilization of the monument which come from. In specific, lime mortars coming from residences have more or less the same structure, whereas the preparation technique differs for lime mortars coming from tombs and walls. The weathering effects on the porous system of the mortars are studied by neutron scattering. (author) [1] Brown, P.W., and Clifton, J.R., 'Air pollution and conservation', eds. J. Roswall and S. Aleby, 225 (1988), Elsevier, Amsterdam.; [2] N. Zouridakis, J.F. Sliege, A. Person et al., Archaeometry, 60 (1987) 29

Suitability of a lime source high in manganese as a feed ingredient ...

African Journals Online (AJOL)

plasma enzyme levels, mineral concentrations in plasma, faeces and kidneys, mineral content of livers, haematology, hislopathol- ogy of livers and kidneys and bone measurements.It is concluded that the Ouplaas lime, .... Table 1 Mineral composition of the pure lime sources (dry basis). Lime sources. Na. (vo). Mg. (vo). K.

Phylogenetic origin of limes and lemons revealed by cytoplasmic and nuclear markers.

Science.gov (United States)

Curk, Franck; Ollitrault, Frédérique; Garcia-Lor, Andres; Luro, François; Navarro, Luis; Ollitrault, Patrick

2016-04-01

The origin of limes and lemons has been a source of conflicting taxonomic opinions. Biochemical studies, numerical taxonomy and recent molecular studies suggested that cultivated Citrus species result from interspecific hybridization between four basic taxa (C. reticulata,C. maxima,C. medica and C. micrantha). However, the origin of most lemons and limes remains controversial or unknown. The aim of this study was to perform extended analyses of the diversity, genetic structure and origin of limes and lemons. The study was based on 133 Citrus accessions. It combined maternal phylogeny studies based on mitochondrial and chloroplastic markers, and nuclear structure analysis based on the evaluation of ploidy level and the use of 123 markers, including 73 basic taxa diagnostic single nucleotide polymorphism (SNP) and indel markers. The lime and lemon horticultural group appears to be highly polymorphic, with diploid, triploid and tetraploid varieties, and to result from many independent reticulation events which defined the sub-groups. Maternal phylogeny involves four cytoplasmic types out of the six encountered in the Citrus genus. All lime and lemon accessions were highly heterozygous, with interspecific admixture of two, three and even the four ancestral taxa genomes. Molecular polymorphism between varieties of the same sub-group was very low. Citrus medica contributed to all limes and lemons and was the direct male parent for the main sub-groups in combination with C. micrantha or close papeda species (for C. aurata, C. excelsa, C. macrophylla and C. aurantifolia--'Mexican' lime types of Tanaka's taxa), C. reticulata(for C. limonia, C. karna and C. jambhiri varieties of Tanaka's taxa, including popular citrus rootstocks such as 'Rangpur' lime, 'Volkamer' and 'Rough' lemons), C. aurantium (for C. limetta and C. limon--yellow lemon types--varieties of Tanaka's taxa) or the C. maxima × C. reticulate hybrid (for C. limettioides--'Palestine sweet' lime types--and C

Liming of acid tropical soils: practice, prospects and constraints ...

African Journals Online (AJOL)

But the incidental inclusion of liming materials in fertilizers has not been effective and sustainable due to the intensive land use activities, constant application of acid-forming chemical fertilizers, leaching losses of bases and crop removal. Liming materials themselves vary in their calcium and magnesium contents and ...

Incorporation of turmeric-lime mixture during the preparation of ...

African Journals Online (AJOL)

GREGO

2007-03-19

Mar 19, 2007 ... behaviour) of 2 min-blanched samples (both treated and control) were the maximum among other corresponding puree samples. Thus, 2 min blanching time may be preferred for the preparation of this new type of turmeric-lime treated tomato puree product. Key words: Turmeric-lime, Lycopersicon ...

Grainstones and cementstone mounds: The Trogkofel summit section (Lower Permian, Carnic Alps, Austria).

Science.gov (United States)

Schaffhauser, M.; Sanders, D.; Krainer, K.

2009-04-01

are overgrown by abundant, thick fringes and botryoids of fibrous cement that is interpreted as calcitized aragonite cement. In addition, brachiopods, crustose red algae, and a few solitary and colonial rugose corals are typical. By volume, the former aragonite cement comprises the majority of the mounds. Intrinsic pores within the cementstone fabrics typically are filled by micropeloidal grainstone and/or by lime mudstone. The Trogkofel Limestone is locally dolomitized. Replacement dolomites show a wide range of crystal shapes and textures, but overall comprise (a) finely-crystalline, limpid dolostone of xenotopic or hypidiotopic fabrics that broadly mimick the texture of replaced sediment and cements, (b) coarse-crystalline fabrics of hypidiotopic to idiotopic, limpid or optically zoned dolomite, and (c) replacement saddle dolomite. The Trogkofel Limestone is riddled by karstic dykes and caverns that are mainly filled by, both or either of, geopetally-laminated red lime mudstone, terrigenous red sandstones, or thick fringes of fibrous cement. In the karstic cavity fills, packages of convolute geopetal lamination and brecciated internal sediments (internal seismites) overlain by infills with non-convolute lamination, fracture of fibrous cements, and dykes filled by multi-phase fracture breccias record tectonism during or after deposition of the Trogkofel Limestone. The Trogkofel Limestone is capped by a truncation surface which, in turn, is overlain by an interval of extremely poorly sorted, thick-bedded breccias with a former matrix of lime mudstone ("Trogkofel Breccia"). Both the components and the matrix of the Trogkofel Breccia are dolomitized. We interpret the facies and facies architecture of the eastern cliff section of Trogkofel as succession from the seaward side of a "grainstone-dominated" platform margin with cementstone mounds. The lack of clear-cut vertical trends in prevalent facies suggests that the platform margin developed mainly by aggradation. The

40 CFR 180.1231 - Lime; exemption from the requirement of a tolerance.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Lime; exemption from the requirement... From Tolerances § 180.1231 Lime; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of lime. [70 FR 33363, June 8, 2005] ...

Lime-Stabilized Black Cotton Soil and Brick Powder Mixture as Subbase Material

Directory of Open Access Journals (Sweden)

S. Srikanth Reddy

2018-01-01

Full Text Available Various researchers, for the past few decades, had tried to stabilize black cotton soil using lime for improving its shrinkage and swelling characteristics. But these days, the cost of lime has increased resulting in increase in need for alternative and cost effective waste materials such as fly ash and rice husk ash. Brick powder, one among the alternative materials, is a fine powdered waste that contains higher proportions of silica and is found near brick kilns in rural areas. The objective of the study is to investigate the use of lime-stabilized black cotton soil and brick powder mixture as subbase material in flexible pavements. Black cotton soil procured from the local area, tested for suitability as subbase material, turned out to be unsuitable as it resulted in very less CBR value. Even lime stabilization of black cotton soil under study has not showed up the required CBR value specified for the subbase material of flexible pavement by MORTH. Hence the lime-stabilized black cotton soil is proportioned with brick powder to obtain optimum mixture that yields a better CBR value. The mixture of 20% brick powder and 80% lime-stabilized black cotton soil under study resulted in increase in the CBR value by about 135% in comparison with lime-stabilized black cotton soil. Thus it is promising to use the mixture of brick powder and lime-stabilized black cotton soil as subbase material in flexible pavements.

New waste based clinkers: Belite and lime formulations

International Nuclear Information System (INIS)

Raupp-Pereira, Fabiano; Ball, Richard James; Rocha, Joao; Labrincha, Joao A.; Allen, Geoffrey C.

2008-01-01

This work describes the formulation of new belite-based (CR2) and lime-based (CR3) cementitious materials derived from industrial wastes, such as sludges (generated in the Al-anodising and surface coating industrial processes, potable water filtration/cleaning operations and in marble sawing processes) and foundry sand. Powder mixtures were prepared and fired at different temperatures. For comparison, similar formulations were prepared with pre-treated and commercially available natural raw materials and processed in similar conditions. The thermal process was followed by differential scanning calorimetry (DSC) and high-temperature powder X-ray diffraction (HT-XRD) studies. The CR2 clinker was found to contain belite as the main cementitious phase, the main polymorph being identified by NMR. The CR3 clinker contained common cementitious phases, such as C 3 A and C 3 S, but free lime and calcium aluminium oxide sulphates were also identified by high temperature XRD and NMR. Then the corresponding cement was prepared and the evolution of the mechanical strength with time was evaluated. The lime-based cement obtained from wastes shows a stronger hardening character than the standard material, which tends to show dusting phenomena due to the presence of a reasonable amount of free lime (as the result of its expansive reaction with ambient moisture). Some fluxing impurities (e.g. alkalis) present in the waste materials improve the overall reactivity of the mixture and induces the combination of the lime in CR3. Raman, XPS and FIB techniques were used to fully characterise the aged cements

The influence of petrography, mineralogy and chemistry on burnability and reactivity of quicklime produced in Twin Shaft Regenerative (TSR) kilns from Neoarchean limestone (Transvaal Supergroup, South Africa)

Science.gov (United States)

Vola, Gabriele; Sarandrea, Luca; Della Porta, Giovanna; Cavallo, Alessandro; Jadoul, Flavio; Cruciani, Giuseppe

2017-12-01

This study evaluates the influence of chemical, mineralogical and petrographic features of the Neoarchean limestone from the Ouplaas Mine (Griqualand West, South Africa) on its burnability and quicklime reactivity, considering the main use as raw material for high-grade lime production in twin shaft regenerative (TSR) kilns. This limestone consists of laminated clotted peloidal micrite and fenestrate microbial boundstone with herringbone calcite and organic carbon (kerogen) within stylolites. Diagenetic modifications include hypidiotopic dolomite, micrite to microsparite recrystallization, stylolites, poikilotopic calcite, chert and saddle dolomite replacements. Burning and technical tests widely attest that the Neoarchean limestone is sensitive to high temperature, showing an unusual and drastically pronounced sintering or overburning tendency. The slaking reactivity, according to EN 459-2 is high for lime burnt at 1050 °C, but rapidly decreases for lime burnt at 1150 °C. The predominant micritic microbial textures, coupled with the organic carbon, are key-factors influencing the low burnability and the high sintering tendency. The presence of burial cementation, especially poikilotopic calcite, seems to promote higher burnability, either in terms of starting calcination temperature, or in terms of higher carbonate dissociation rate. In fact, the highest calcination velocity determined by thermal analysis is consistent with the highest slaking reactivity of the lower stratum of the quarry, enriched in poikilotopic calcite. Secondly, locally concentered dolomitic marly limestones, and sporadic back shales negatively affects the quicklime reactivity, as well. This study confirms that a multidisciplinary analytical approach is essential for selecting the best raw mix for achieving the highest lime reactivity in TSR kilns.

The Strength Behaviour of Lime Stabilized Organic Clay Soil Modified by Catalyst Additeives

Directory of Open Access Journals (Sweden)

Khitam Abdulhussein Saeed

2016-12-01

Full Text Available The organic clay soil can be found in many large size reclaimed lands. These soils present enormously high settlement potential and low strength that needs to be improved by means of effective ground improvement techniques. One of the low cost techniques is to modify the soil with lime in-situ to make it suitable for construction and allow it to increase in strength by pozzolanic reactions between lime and clay minerals. Lime is known to be an effective stabilization material for clayey soil. Nevertheless, its effectiveness may be less with organic clay due to low effective strength properties. Thus, this study concerns the addition of catalyst i.e. zeolite which may improve the performance of lime stabilization to accelerate lime-organic clay reactions. The unconfined compressive test (UCT is conducted on remoulded samples (38mm x 80mm for 0, 7, 14 , 28, and 90 days of curing period. The addition of synthetic zeolite in lime-organic stabilized soil has increased the soil strength by 185% at 90 days curing period at the design mix of organic clay + 10% lime +10% zeolite. The higher value of UCS indicates that zeolite is an effective catalyst to enhance lime stabilization.

40 CFR 63.7081 - Am I subject to this subpart?

Science.gov (United States)

2010-07-01

... calcium carbonate from water softening processes. (1) An LMP is an establishment engaged in the manufacture of lime product (calcium oxide, calcium oxide with magnesium oxide, or dead burned dolomite) by...

Analysis on soil compressibility changes of samples stabilized with lime

Directory of Open Access Journals (Sweden)

Elena-Andreea CALARASU

2016-12-01

Full Text Available In order to manage and control the stability of buildings located on difficult foundation soils, several techniques of soil stabilization were developed and applied worldwide. Taking into account the major significance of soil compressibility on construction durability and safety, the soil stabilization with a binder like lime is considered one of the most used and traditional methods. The present paper aims to assess the effect of lime content on soil geotechnical parameters, especially on compressibility ones, based on laboratory experimental tests, for several soil categories in admixture with different lime dosages. The results of this study indicate a significant improvement of stabilized soil parameters, such as compressibility and plasticity, in comparison with natural samples. The effect of lime stabilization is related to an increase of soil structure stability by increasing the bearing capacity.

Liming effect in the degradation of 14C-glyphosate in soils

International Nuclear Information System (INIS)

Arantes, Sayonara A.C.M.; Lavorenti, Arquimedes

2007-01-01

Liming is soil fertility management practice essential in tropical soils, in general extremely acidic. This practice, by influencing physical, chemical and biological features of soils may influence the behavior of organic molecules in soils. The glyphosate is one the most widely used pesticides in Brazil in several cultures to pest management control. Studies on its fate in soil are still incipient, mainly under the effect of liming practice The objective of the present study was to verify the effect of liming practice in the degradation of glyphosate in Red Latosol (LE) and Quartzarenic Neosol (RQ) soils and also in the microbial activity of the same soils. The experiment was conducted in a completely randomized design in a 2 x 2 factorial scheme, corresponding to two soils and two management conditions (with liming and without liming), with four replicates. The Radiometric technique was utilized to evaluate the evolution the 14 CO 2 at intervals of 7 days, during 70 days. The study of microbial activity was conducted parallel to the degradation experiment, using the methodology of radiolabelled glucose ( 14 C-glucose), which was measured at intervals of fourteen days, during 70 days. The results showed that in the studied soils, the liming increased the 14 C-glyphosate mineralization and the microbial activity. (author)

Effect of Lime Stabilization on Vertical Deformation of Laterite Halmahera Soil

Science.gov (United States)

Saing, Zubair; Djainal, Herry

2018-04-01

In this paper, the study was conducted to determine the lime effect on vertical deformation of road base physical model of laterite Halmahera soil. The samples of laterite soil were obtained from Halmahera Island, North Maluku Province, Indonesia. Soil characteristics were obtained from laboratory testing, according to American Standard for Testing and Materials (ASTM), consists of physical, mechanical, minerals, and chemical. The base layer of physical model testing with the dimension; 2m of length, 2m of width, and 1.5m of height. The addition of lime with variations of 3, 5, 7, an 10%, based on maximum dry density of standard Proctor test results and cured for 28 days. The model of lime treated laterite Halmahera soil with 0,1m thickness placed on subgrade layer with 1,5m thickness. Furthermore, the physical model was given static vertical loading. Some dial gauge is placed on the lime treated soil surface with distance interval 20cm, to read the vertical deformation that occurs during loading. The experimentals data was analyzed and validated with numerical analysis using finite element method. The results showed that the vertical deformation reduced significantly on 10% lime content (three times less than untreated soil), and qualify for maximum deflection (standard requirement L/240) on 7-10% lime content.

Efficacy and phytotoicity of lime sulphur in organic apple production

NARCIS (Netherlands)

Holb, I.J.; Jong, de P.F.; Heijne, B.

2003-01-01

Curative and preventive efficacy and phytotoxicity of lime sulphur spray schedules, based on a warning system, were evaluated in the Netherlands during two growing seasons under field conditions. In most cases, lime sulphur treatments applied either curatively or preventively resulted in

Carbonation of lime and cement stabilized layers in road construction

CSIR Research Space (South Africa)

Netterberg, F

1984-04-01

Full Text Available The problem of deterioration of lime, lime-slag and cement stabilized pavement layers during curing, before sealing and in service is partly ascribed to carbonation of the stabilizer during curing and subsequent exposure to the atmosphere before...

Lime application methods, water and bottom soil acidity in fresh water fish ponds

Directory of Open Access Journals (Sweden)

Queiroz Julio Ferraz de

2004-01-01

Full Text Available Although some methods for determining lime requirement of pond soils are available and commonly used, there is still no consensus on whether it is more effective to apply liming materials to the bottoms of empty ponds or to wait and apply them over the water surface after ponds are filled. There is also little information on how deep lime reacts in pond sediment over time, and whether the depth of reaction is different when liming materials are applied to the water or to the soil. Therefore, three techniques for treating fish ponds with agricultural limestone were evaluated in ponds with clayey soils at a commercial fish farm. Amounts of agricultural limestone equal to the lime requirement of bottom soils were applied to each of three ponds by: direct application over the pond water surface; spread uniformly over the bottom of the empty pond; spread uniformly over the bottom of the empty pond followed by tilling of the bottom. Effectiveness of agricultural limestone applications did not differ among treatment methods. Agricultural limestone also reacted quickly to increase total alkalinity and total hardness of pond water to acceptable concentrations within 2 weeks after application. The reaction of lime to increase soil pH was essentially complete after one to two months, and lime had no effect below a soil depth of 8 cm. Tilling of pond bottoms to incorporate liming materials is unnecessary, and tilling consumes time and is an expensive practice; filled ponds can be limed effectively.

Presence of sulfate does not inhibit low-temperature dolomite precipitation

NARCIS (Netherlands)

Sánchez-Román, Mónica; McKenzie, Judith A.; de Luca Rebello Wagener, Angela; Rivadeneyra, Maria A.; Vasconcelos, Crisógono

2009-01-01

The hypothesis that sulfate inhibits dolomite formation evolved from geochemical studies of porewaters from deep-sea sedimentary sequences and has been tested with hydrothermal experiments. We examined the sulfate inhibition factor using aerobic culture experiments with Virgibacillus marismortui and

Expansion reduction of clayey soils through Surcharge application and Lime Treatment

Directory of Open Access Journals (Sweden)

T. López-Lara

2017-12-01

Full Text Available Expansive clayey soils produce heaving and cracking of floor slabs and walls. Expansive soils owe their characteristics to the presence of swelling clay minerals. This soil expands and contracts due to changes in the moisture content of the soil. In this study the surcharge required to counteract soil expansion was measured in natural expansive soils (untreated soils and lime treated soils starting at 19.61 kPa (2 Ton/m2 and continuing with increments of 19.61 kPa. Additionaly in lime treated soils the amount of lime was determined under different surcharges in order to reduce the expansion. The test results indicated that the surcharges applied to untreated soils were not proportional to the decrease of expansion which is probably due to the increase of soil density. In fact, only the initial surcharge of 19.61 kPa significantly decreased the expansion. According to the results, the soil expansion was considerably reduced (1.54% with the surcharge of 78.45 kPa, therefore this surcharge can be considered as the Swelling pressure. On the other hand the soil tested (high compressibility clay was stabilized with 6% of lime (without surcharges which was determined with the lowest value of liquid limit and plastic index as well as expansion test. After the application of surcharges and lime treatment to expansive soil, the surcharges of 39.22 kPa and 58.84 kPa decreased expansion and increased their resistance. This was concluded by similar low values of expansion (without settlements under both surcharges of each treated soil tested (2, 4 and 6% of lime. It can be concluded that the surcharge contributed to the decrease of soil expansion due to the decrease of the amount of lime required (6% without surcharge. So, 4% of lime was enough for the surcharge of 19.61 kPa and 2% of lime required the surcharge minimum of 39.22 kPa. This shows that the surcharge of a house on expansive soil reduces soil expansion and therefore reduces costs of any

CHEMICAL SOIL ATTRIBUTES AS AFFECTED BY LIME AND GYPSUM SURFACE APPLICATION

Directory of Open Access Journals (Sweden)

A. Mantovani

2017-10-01

Full Text Available The gypsum is a soil condition end it has to function contribute to the elimination or reduction of aluminum in the soil in depth. Still, it can contribute to the distribution of nutrients in the soil profile more uniformly and thus increasing the productivity of crops. This study aimed to evaluate the influence of gypsum application, with and without lime, on soil chemical properties and soybean yield, in a no-till system. The experiment was carried in Campos Novos, Santa Catarina State, Brazil, with a randomized block design and split plot design with four replications, the main portion was distributed gypsum doses (1000, 2000, 4000 and 6000 kg ha-1 without incorporation, and the split plot (with and without lime and the liming was 2,000 kg ha-1. We evaluated the performance of components and productivity of soybeans. It was also analyzed the soil pH and Ca, Mg, S and Al at 0-20 and 20-40 cm. The application of gypsum at the rates tested surface with and without lime did not affect the yield components and soybean productivity. At 0-20 cm soil depth lime application increased soil pH by 0.3 units on the average rates of gypsum, but in the 20-40 cm layer was not found effect of lime and gypsum in pH ground due to the short time between application and evaluation. In areas with and without lime contents of Ca and S in the two layers evaluated increased with increasing rates of gypsum, since Mg has difference with the lime application on a 0-20 cm to dose 4000 kg ha-1 and the lime in the gypsum rates and Al decreased with increasing dose gypsum average in the 20-40 cm layer depth. The application of gypsum and limestone softened the negative effects of soil acidity and the increase mainly of calcium and sulfur at 0-20 cm, with less efficient effects in the 20-40 cm layer due to the soil is clayey and the period between the implementation and evaluation be 120 days.

Producer gas and its use for the manufacture of lime

Energy Technology Data Exchange (ETDEWEB)

Gupta, A K; Kumar, S

1976-04-01

An analysis of available data indicates that coal-based producer gas is superior to coal or wood as a fuel for lime kilns and much more readily available than oil or natural gas. With producer gas, chemical-grade lime is obtained, and the kiln capacity is increased, so that a smaller unit can be used or more lime obtained. With a mixture of coal and wood as the fuel, the lime produced is contaminated with ash. The added cost of the gas-producer unit can be paid out in one year owing to the greater demand for and the consequent higher prices obtainable for the chemical-grade product. In addition, the flue gases from the kiln can be used in place of steam to heat the gas producer, but experimental studies are needed to determine the magnitude of the savings in fuel consumption. 15 references.

Interpreting chemistry and technology of lime binders and implementing it in the conservation field

Directory of Open Access Journals (Sweden)

Georgia Zacharopoulou

2009-01-01

Full Text Available The objective of the paper is the compilation, review and dissemination of updated scientific knowledge on lime theory and technology in the field of heritage conservation. The strong evidence of the last decade's research on the positive effect of the - not demonstrable by a chemical equation – 'key' missing link of the maturation process is highlighted. It is demonstrated that the exceptional perfor -mance characteristics of durable lime based mortars predominately rely on the capacity for rapid, efficient and extensive carbonation of the air-hardening phase of limes, in particular when matured (nanoparticle wet slaked lime putties are used; and on the chemical and mechanical stability of the strength components (principally CSHs of the hydraulic phase of limes, which is higher in their more crystalline forms of historical lime-pozzolan mixtures than in their amorphous forms of modern cements. Hence, physicochemical adhesion and cohesion bonds both at the lime matrix and at the binder/aggregate interfaces are ensured imparting minimization of cracks and durability to lime based mortars and historic masonries. The comprehensive documentation of the former leads to optimal materials and procedures to preserve our cultural heritage.

Can hydrate dissolution experiments predict the fate of a natural hydrate system?

Energy Technology Data Exchange (ETDEWEB)

Hester, K.C.; Peltzer, E.T.; Dunk, R.M.; Walz, P.M.; Brewer, P.G. [Monterey Bay Aquarium Research Inst., Moss Landing, CA (United States); Dendy Sloan, E. [Colorado School of Mines, Golden, CO (United States). Center for Hydrate Research

2008-07-01

Gas hydrates are naturally occurring compounds found in permafrost regions and in oceans. In the natural environment, sufficient temperature and pressure conditions for hydrate formation exist over a significant portion of the ocean. However, in addition to pressure and temperature, the chemical potential of the gas in the hydrate must be equal to the surrounding waters. If the concentration of the gas in surrounding water is under-saturated with respect to the gas in the hydrate, the hydrate will dissolve to drive the system towards chemical equilibrium. This paper presented a dissolution study of exposed hydrate from outcrops at Barkley Canyon, located off Vancouver Island, British Columbia. A previous field experiment on synthetic methane hydrate samples had demonstrated that mass transfer controlled dissolution in under-saturated seawater. However, seafloor hydrate outcrops have been shown to have significant longevity compared to expected dissolution rates based upon convective boundary layer diffusion calculations. An in-situ dissolution experiment was performed on two distinct natural hydrate fabrics in order to help resolve this apparent disconnect between the dissolution rates of synthetic and natural hydrate. The paper presented a map of Barkley Canyon and discussed the field measurements and methods for the study. Exposed outcrops of gas hydrates were cored using a specially constructed stainless steel coring device and a hydraulic ram was located inside the corer. Hydrate samples were cored directly using the a manipulator arm and then injected into a sampling cell. The hydrate was then added to an open mesh exposure container, which allowed for exposure to ambient benthic currents with minimal disturbance. As well, in order to observe the slow dissolution of the hydrate in seawater at Barkley Canyon, time-lapse photography was employed. Last, the paper presented the results of the hydrate fabric porosities and hydrate dissolution rates. It was

Lime sulfur toxicity to broad mite, to its host plants and to natural enemies.

Science.gov (United States)

Venzon, Madelaine; Oliveira, Rafael M; Perez, André L; Rodríguez-Cruz, Fredy A; Martins Filho, Sebastião

2013-06-01

An acaricidal effect of lime sulfur has not been demonstrated for Polyphagotarsonemus latus. However, lime sulfur can cause toxicity to natural enemies and to host plants. In this study, the toxicity of different concentrations of lime sulfur to P. latus, to the predatory mite Amblyseius herbicolus and to the predatory insect Chrysoperla externa was evaluated. Additionally, the phytotoxicity of lime sulfur to two P. latus hosts, chili pepper and physic nut plants, was determined. Lime sulfur at a concentration of 9.5 mL L(-1) restrained P. latus population growth. However, this concentration was deleterious to natural enemies. The predatory mite A. herbicolus showed a negative value of instantaneous growth rate, and only 50% of the tested larvae of C. externa reached adulthood when exposed to 10 mL L(-1) . Physic nut had severe injury symptoms when sprayed with all tested lime sulfur concentrations. For chili pepper plants, no phytoxicity was observed at any tested concentration. Lime sulfur might be used for P. latus control on chili pepper but not on physic nut owing to phytotoxicity. Care should be taken when using lime sulfur in view of negative effects on natural enemies. Selective lime sulfur concentration integrated with other management tactics may provide an effective and sustainable P. latus control on chili pepper. © 2012 Society of Chemical Industry.

Is a combination of different natural substances suitable for slug (Arion spp.) control?

Energy Technology Data Exchange (ETDEWEB)

Laznik, Ž.; Trdan, S.

2016-11-01

In a laboratory study we investigated the contact and barrier efficacy of different natural substances (wood ash, sawdust, hydrated lime, and diatomaceous earth) against slugs of the genus Arion, an important agricultural pest. Natural substances were tested individually and in combination with each other. The experiment was carried out in plastic petri dishes and in glass insectaria. Moistened tampons and fresh leaves of lettuce were placed into both experimental arenas. The slugs were starved for 48 hours prior to the experiment. Six categories of behaviour were identified for slugs in the presence of the natural substances: (1) slug survived the experiment, (2) slug died during the experiment, (3) slug crossed the barrier, (4) slug did not cross the barrier, (5) slug fed on the lettuce, and (6) slug did not feed on the lettuce. The effect of different treatments (natural substances) was significant. The results of our study have shown that hydrated lime had the best contact efficacy on slugs (the mortality of slugs was 100%), both individually and in combination with other substances. The treatments with hydrated lime also proved to be the most efficient barrier preventing slugs from feeding on lettuce. Hydrated lime shows great potential in Arion control in our investigation; however, further research is needed to investigate the practical value (how to avoid the problem when the substance becomes wet), safety and economics of hydrated lime used in this way. (Author)

A novel eco-friendly technique for efficient control of lime water softening process.

Science.gov (United States)

Ostovar, Mohamad; Amiri, Mohamad

2013-12-01

Lime softening is an established type of water treatment used for water softening. The performance of this process is highly dependent on lime dosage. Currently, lime dosage is adjusted manually based on chemical tests, aimed at maintaining the phenolphthalein (P) and total (M) alkalinities within a certain range (2 P - M > or = 5). In this paper, a critical study of the softening process has been presented. It has been shown that the current method is frequently incorrect. Furthermore, electrical conductivity (EC) has been introduced as a novel indicator for effectively characterizing the lime softening process.This novel technique has several advantages over the current alkalinities method. Because no chemical reagents are needed for titration, which is a simple test, there is a considerable reduction in test costs. Additionally, there is a reduction in the treated water hardness and generated sludge during the lime softening process. Therefore, it is highly eco-friendly, and is a very cost effective alternative technique for efficient control of the lime softening process.

Efficacy of road bond and condor as soil stabilizers : final report.

Science.gov (United States)

2013-08-01

The Oklahoma Department of Transportation (ODOT) uses lime-based stabilizers including quick lime, hydrated lime, Class C fly ash (CFA) and cement kiln dust (CKD) to increase bearing capacity of fine-grained subgrade soils within the state of Oklahom...

Investigation of Copper Sorption by Sugar Beet Processing Lime Waste

Science.gov (United States)

In the western United States, sugar beet processing for sugar recovery generates a lime-based waste product (~250,000 Mg yr-1) that has little liming value in the region’s calcareous soils. This area has recently experienced an increase in dairy production, with dairi...

Some studies on the reaction between fly ash and lime

Indian Academy of Sciences (India)

Unknown

Blain's air permeability apparatus was used for ... Pulverized lime with high per- centage of CaO (> 80 ... kept in a low-pressure autoclave at an average steam pressure and ... ing the solubility of lime in a solvent containing 1 part by volume of ...

Liming effect in the degradation of 14C-glyphosate in soils

Energy Technology Data Exchange (ETDEWEB)

Arantes, Sayonara A.C.M.; Lavorenti, Arquimedes [Universidade de Sao Paulo (USP), Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz]. E-mails: samoreno@esalq.usp.br; alavoren@esalq.usp.br; Tornisielo, Valdemar L. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)]. E-mail: vltornis@cena.usp.br

2007-07-01

Liming is soil fertility management practice essential in tropical soils, in general extremely acidic. This practice, by influencing physical, chemical and biological features of soils may influence the behavior of organic molecules in soils. The glyphosate is one the most widely used pesticides in Brazil in several cultures to pest management control. Studies on its fate in soil are still incipient, mainly under the effect of liming practice The objective of the present study was to verify the effect of liming practice in the degradation of glyphosate in Red Latosol (LE) and Quartzarenic Neosol (RQ) soils and also in the microbial activity of the same soils. The experiment was conducted in a completely randomized design in a 2 x 2 factorial scheme, corresponding to two soils and two management conditions (with liming and without liming), with four replicates. The Radiometric technique was utilized to evaluate the evolution the {sup 14}CO{sub 2} at intervals of 7 days, during 70 days. The study of microbial activity was conducted parallel to the degradation experiment, using the methodology of radiolabelled glucose ({sup 14}C-glucose), which was measured at intervals of fourteen days, during 70 days. The results showed that in the studied soils, the liming increased the {sup 14}C-glyphosate mineralization and the microbial activity. (author)

Gas hydrate nucleation

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

The overall aim of the project was to gain more knowledge about the kinetics of gas hydrate formation especially the early growth phase. Knowledge of kinetics of gas hydrate formation is important and measurements of gas hydrate particle size and concentration can contribute to improve this knowledge. An experimental setup for carrying out experimental studies of the nucleation and growth of gas hydrates has been constructed and tested. Multi wavelength extinction (MWE) was the experimental technique selected for obtaining particle diameter and concentration. The principle behind MWE is described as well as turbidity spectrum analysis that in an initial stage of the project was considered as an alternative experimental technique. Details of the experimental setup and its operation are outlined. The measuring cell consists of a 1 litre horizontal tube sustaining pressures up to 200 bar. Laser light for particle size determination can be applied through sapphire windows. A description of the various auxiliary equipment and of another gas hydrate cell used in the study are given. A computer program for simulation and analysis of gas hydrate experiments is based on the gas hydrate kinetics model proposed by Skovborg and Rasmussen (1993). Initial measurements showed that knowledge of the refractive index of gas hydrates was important in order to use MWE. An experimental determination of the refractive index of methane and natural gas hydrate is described. The test experiments performed with MWE on collectives of gas hydrate particles and experiments with ethane, methane and natural gas hydrate are discussed. Gas hydrate particles initially seem to grow mainly in size and at latter stages in number. (EG) EFP-94; 41 refs.

Gas hydrate nucleation

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-31

The overall aim of the project was to gain more knowledge about the kinetics of gas hydrate formation especially the early growth phase. Knowledge of kinetics of gas hydrate formation is important and measurements of gas hydrate particle size and concentration can contribute to improve this knowledge. An experimental setup for carrying out experimental studies of the nucleation and growth of gas hydrates has been constructed and tested. Multi wavelength extinction (MWE) was the experimental technique selected for obtaining particle diameter and concentration. The principle behind MWE is described as well as turbidity spectrum analysis that in an initial stage of the project was considered as an alternative experimental technique. Details of the experimental setup and its operation are outlined. The measuring cell consists of a 1 litre horizontal tube sustaining pressures up to 200 bar. Laser light for particle size determination can be applied through sapphire windows. A description of the various auxiliary equipment and of another gas hydrate cell used in the study are given. A computer program for simulation and analysis of gas hydrate experiments is based on the gas hydrate kinetics model proposed by Skovborg and Rasmussen (1993). Initial measurements showed that knowledge of the refractive index of gas hydrates was important in order to use MWE. An experimental determination of the refractive index of methane and natural gas hydrate is described. The test experiments performed with MWE on collectives of gas hydrate particles and experiments with ethane, methane and natural gas hydrate are discussed. Gas hydrate particles initially seem to grow mainly in size and at latter stages in number. (EG) EFP-94; 41 refs.

Gas hydrates

Digital Repository Service at National Institute of Oceanography (India)

Ramprasad, T.

, not all of them are white like snow. Some hydrates from the deep Gulf of Mexico are richly colored in shades of yellow, orange, or even red. The ice-like masses are beautiful, and contrast with the dull gray of deep sea muds. Hydrates from the Blake... volcanoes and associated gas hydrates: Marine Geology, v. 167, p. 29-42. Milkov, A.V. and R. Sassen, 2001a, Estimate of gas hydrate resource, northwestern Gulf of Mexico continental slope: Marine Geology, v. 179, pp. 71-83. Milkov, A.V., Sassen, R...

Long-term field-scale experiment on using lime filters in an agricultural catchment.

Science.gov (United States)

Kirkkala, Teija; Ventelä, Anne-Mari; Tarvainen, Marjo

2012-01-01

The River Yläneenjoki catchment in southwest Finland is an area with a high agricultural nutrient load. We report here on the nutrient removal performance of three on-site lime-sand filters (F1, F2, and F3), established within or on the edge of the buffer zones. The filters contain burnt lime (CaO) or spent lime [CaO, Ca(OH), and CaCO]. Easily soluble lime results in a high pH level (>11) and leads to an efficient precipitation of soluble phosphorus (P) from the runoff. Water samples were taken from the inflow and outflow of each site in different hydrological situations. The length of the monitoring period was 4 yr for F1, 6 yr for F2, and 1.5 yr for F3. F1 and F2 significantly reduced the suspended solids (SS), total P (PTOT), and dissolved reactive P (DRP) in the treated water. The proportional reduction (%) varied but was usually clearly positive. Filter F3 was divided into two equal parts, one containing burnt lime and the other spent lime. Both filter parts removed PTOT and SS efficiently from the water; the burnt-lime part also removed DRP. The mixed-lime part removed DRP for a year, but then the efficiency decreased. The effect of filters on nitrogen compounds varied. We conclude that sand filters incorporating lime can be used together with buffer zones to reduce both P and SS load to watercourses. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Influence of Lime and Phosphorus Application Rates on Growth of Maize in an Acid Soil

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Peter Asbon Opala

2017-01-01

Full Text Available The interactive effects of lime and phosphorus on maize growth in an acid soil were investigated in a greenhouse experiment. A completely randomized design with 12 treatments consisting of four lime levels, 0, 2, 10, and 20 t ha−1, in a factorial combination with three phosphorus rates, 0, 30, and 100 kg ha−1, was used. Maize was grown in pots for six weeks and its heights and dry matter yield were determined and soils were analyzed for available P and exchangeable acidity. Liming significantly reduced the exchangeable acidity in the soils. The effect of lime on available P was not significant but available P increased with increasing P rates. There was a significant effect of lime, P, and P by lime interactions on plant heights and dry matter. Without lime application, dry matter increased with increasing P rates but, with lime, dry mattes increased from 0 to 30 kg P ha−1 but declined from 30 to 100 kg P ha−1. The highest dry matter yield (13.8 g pot−1 was obtained with a combined 2 t ha−1 of lime with 30 kg P ha−1 suggesting that lime application at low rates combined with moderate amounts of P would be appropriate in this soil.

Recycle of fired phosphogypsum waste product as a cement replacement and its role on the hydration and strength development of pastes

International Nuclear Information System (INIS)

Tantawi, S.H.

2005-01-01

The effect of Partially up to fully substituted of treated phosphogypsum x(PG) for natural gypsum on the physico- mechanical as well as kinetic of hydration of ordinary Portland cement has been discussed . The results show that by increasing PG % the water to cement ratio decreased while the initial and final setting times increased So PG acts as a retarder and water reducer . The retardation effect may be attributed to formation of ettringite layer which formed on the surface of C3A of cement pastes . The chemically combined water, free lime content and bulk density increased with curing time and with PG content for all cement pastes up to 90 days due to increasing of the rate of hydration. The compressive strength increased by increasing of PG % due to formation of anhydrite , changes in major oxides content and reduction of impurities . X-Ray Diffraction, SEM and DTA of some samples have been studied

Coolside waste management demonstration OCDO grant agreement No. CDO/D-902-9. Final report

Energy Technology Data Exchange (ETDEWEB)

Wu, M.; Winschel, R.A. [CONSOL Inc., Library, PA (United States). Research & Development

1997-10-01

The objectives of this project were to evaluate the potential utilization in road construction of wastes produced from the Coolside, LIMB (limestone injection multi-stage burner) and FBC (fluidized-bed combustion) processes, and to specify criteria for landfill disposal of waste from the Coolside process. These three processes are considered to be clean coal technologies. The Coolside process involves injecting an aqueous slurry of hydrated lime into the ductwork downstream of the air preheater in a coal-fired boiler. The hydrated lime captures sulfur dioxide from the flue gas producing anhydrous calcium sulfite and calcium sulfate, which are collected along with the unused hydrated lime and fly ash. The LIMB process involves injection of lime or hydrated lime directly into the furnace to capture sulfur dioxide. The waste consists principally of anhydrous calcium sulfate, lime, and fly ash. Both processes were demonstrated successfully at the Edgewater Station of Ohio Edison in Lorrain, OH, from 1989 to 1992. Circulating fluidized-bed combustion (FBC) is a commercial technology which combines steam generation with SO{sub 2} control by burning coal in a circulating bed of limestone. The waste, chemically similar to LIMB waste, is produced by bleed-off of the bed material and by collection of the flue dust. All three processes produce a dry solid waste, which must either be used or disposed of and managed to ensure environmental compliance and economic feasibility. The project was completed in June 1996.

Imperial Limes - Projections in Medieval Imperial Idea

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Z.Z. Zhekov

2015-08-01

Full Text Available Roman imperial limes from I - V BC was the first state border in world history, which in some sense corresponds to the modern concept of political boundary. It represents sustainable political, military and economic barrier between the Romans and the rest of the world. With minor modifications it retains their basic strategic concept during the period as expressed from the emperors Augustus and Tiberius. Limes become powerful barrier that separates cultural Roman Hellenistic world of the wild barbarian but at the same time limits the constructed infrastructure of roads, forts and towns became a natural cultural, commercial and political mediator between these two initially hostile worlds. In border towns developed a lively trade between Romans and barbarians. Roman traders penetrate inside the barbarian lands getting to know their culture and history. Studying foreign peoples and countries they convey information gathered imperial legate of the Roman population. The same process was developed and of course in the opposite direction. Exchange of information on the other promotes mutual understanding and open living on both sides of the Roman Limes.

The effect of reuse of unhairing-liming residual floats through ...

African Journals Online (AJOL)

STORAGESEVER

2008-09-03

Sep 3, 2008 ... Key words: Unhairing-liming process, reusing, leather industry, environment, bacterial and fungal numbers. INTRODUCTION .... 4.0 x101. -: No growth. Chemical analysis of samples. Chemical analyses of sodium sulphide and lime were done for the regeneration of ULP residual liquors. While preparing ...

Shifting Focus: From Hydration for Performance to Hydration for Health.

Science.gov (United States)

Perrier, Erica T

2017-01-01

Over the past 10 years, literature on hydration biomarkers has evolved considerably - from (de)hydration assessment towards a more global definition of biomarkers of hydration in daily life. This shift in thinking about hydration markers was largely driven by investigating the differences that existed between otherwise healthy individuals whose habitual, ad-libitum drinking habits differ, and by identifying physiological changes in low-volume drinkers who subsequently increase their water intake. Aside from obvious differences in urinary volume and concentration, a growing body of evidence is emerging that links differences in fluid intake with small, but biologically significant, differences in vasopressin (copeptin), glomerular filtration rate, and markers of metabolic dysfunction or disease. Taken together, these pieces of the puzzle begin to form a picture of how much water intake should be considered adequate for health, and represent a shifting focus from hydration for performance, toward hydration for health outcomes. This narrative review outlines the key areas of research in which the global hydration process - including water intake, urinary hydration markers, and vasopressin - has been associated with health outcomes, focusing on kidney and metabolic endpoints. It will also provide a commentary on how various hydration biomarkers may be used in hydration for health assessment. Finally, if adequate water intake can play a role in maintaining health, how might we tell if we are drinking enough? Urine output is easily measured, and can take into account differences in daily physical activity, climate, dietary solute load, and other factors that influence daily water needs. Today, targets have been proposed for urine osmolality, specific gravity, and color that may be used by researchers, clinicians, and individuals as simple indicators of optimal hydration. However, there remain a large number of incomplete or unanswered research questions regarding the

40 CFR 180.1232 - Lime-sulfur; exemption from the requirement of a tolerance.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Lime-sulfur; exemption from the... Exemptions From Tolerances § 180.1232 Lime-sulfur; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of lime-sulfur. [70 FR 33363, June...

Audiovisual Documentation of an International Seminar : Case: LIME

OpenAIRE

Tikkanen, Kirsti; Rönnberg, Mira

2013-01-01

The aim of this Bachelor’s thesis is to create a documentary video of an international seminar held in Kerava, Finland, in June 2013. The seminar was called Learning on Immigration and Multicultural Education (LIME) and it was conducted by Kerava Adult Education Center (later Keravan Opisto). LIME was a two-year intercultural project funded by the European Union. Different non-governmental organizations and adult education centers from eight European countries took part on the project. The ai...

DEVELOPMENT OF TECHNIQUES FOR QUANTITATIVE ANALYSIS OF LIME FLOWERS

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Demyanenko DV

2016-03-01

Full Text Available Introduction. The article is devoted to the development of techniques for quantitative analysis of lime flower in order to make amendments to existing pharmacopoeian monographs for this herbal drug. Lime inflorescences contain lipophilic biologically active substances (BAS causing notable antimicrobial and anti-inflammatory effects and also more polar phenolic compounds with antiulcer activity. Considering this, it’s necessary to regulate all these groups of BAS quantitatively. Materials and methods. For this study six batches of lime flowers harvested in 2008-2009 yrs. in Kharkiv, Rivno and Zhitomir regions were used as crude herbal drug. Loss on drying was determined by routine pharmacopoeian procedures. Total content of lipophilic substances was determined gravimetrically after Soxhlet extraction of samples 1, 5, 7 and 10 g in weight with methylene chloride, considering that by its extracting ability this solvent is close to liquefied difluorochloromethane (freon R22 used by us for obtaining of lipophilic complexes. The duration of complete analytical extraction was determined by infusion of six 10 g assays of lime flowers during 1, 2, 3, 4, 5, 6 hours, then quantity of lipophilic extractives was revealed gravimetrically. Quantity of essential oil in lime flowers was evaluated under the procedure of ЕР7, 2.8.12. Weight of the herbal drug sample was 200 g, distillation rate – 2,5- 3,5 ml/min, volume of distillation liquid (water – 500 ml, volume of xylene in the graduated tube – 0,50 ml. Total flavonoid content recalculated to quercetin was determined after hydrolysis with acidified acetone, withdrawing of flavonoid aglycones with ethylacetate and by further spectrophotometry of their complexes with aluminium chloride. All quantitative determinations were replicated five times for each assay. All chemicals and reagents were of analytical grade. Results and discussion. It was found that adequate accuracy of the analysis of lipophilic

Impacts of Hydrate Distribution on the Hydro-Thermo-Mechanical Properties of Hydrate-Bearing Sediments

Science.gov (United States)

Dai, S.; Seol, Y.

2015-12-01

In general, hydrate makes the sediments hydraulically less conductive, thermally more conductive, and mechanically stronger; yet the dependency of these physical properties on hydrate saturation varies with hydrate distribution and morphology. Hydrate distribution in sediments may cause the bulk physical properties of their host sediments varying several orders of magnitude even with the same amount of hydrate. In natural sediments, hydrate morphology is inherently governed by the burial depth and the grain size of the host sediments. Compare with patchy hydrate, uniformly distributed hydrate is more destructive to fluid flow, yet leads to higher gas and water permeability during hydrate dissociation due to the easiness of forming percolation paths. Water and hydrate have similar thermal conductivity values; the bulk thermal conductivity of hydrate-bearing sediments depends critically on gas-phase saturation. 60% of gas saturation may result in evident thermal conductivity drop and hinder further gas production. Sediments with patchy hydrate yield lower stiffness than that with cementing hydrate but higher stiffness than that with pore filling and loading bearing hydrate. Besides hydrate distribution, the stress state and loading history also play an important role in the mechanical behavior of hydrate-bearing sediments.

Evaluation of dolomitic resources of Uruguay (Minas - Pan de Azucar Region)

International Nuclear Information System (INIS)

Arrighetti, R; Pirelli, H.; Gianotti, V.; humberto.pirelli@dinamige.miem.gub.uy

2007-01-01

This investigation tries - through Phase I and Phase II stages - to get and estimation of the volume of dolomite resources by means of prospecting the region between the city of Minas and the Pan de Azucar hill, Uruguay; with the objective of achieve a reactivation of this area, increasing job offer, commerce, industrial production and construction activities. Phase I is intended to add valuable information about the precise location of calcareous bodies, their basic features, its geochemical characterization and definition of bodies to be studied with higher detail in Phase II. This second stage points to get an evaluation of the Inferred Resources using 1:10 000 maps and lithological sampling networks to obtain a geochemical characterization of the rocky bodies and the core samples extracted by drilling.Keywords: dolomite, exploration, evaluation, Uruguay. (author)

Enhanced inhibition of Aspergillus niger on sedge (Lepironia articulata) treated with heat-cured lime oil.

Science.gov (United States)

Matan, N; Matan, N; Ketsa, S

2013-08-01

This study aimed to examine heat curing effect (30-100°C) on antifungal activities of lime oil and its components (limonene, p-cymene, β-pinene and α-pinene) at concentrations ranging from 100 to 300 μl ml(-1) against Aspergillus niger in microbiological medium and to optimize heat curing of lime oil for efficient mould control on sedge (Lepironia articulata). Broth dilution method was employed to determine lime oil minimum inhibitory concentration, which was at 90 μl ml(-1) with heat curing at 70°C. Limonene, a main component of lime oil, was an agent responsible for temperature dependencies of lime oil activities observed. Response surface methodology was used to construct the mathematical model describing a time period of zero mould growth on sedge as functions of heat curing temperature and lime oil concentration. Heat curing of 90 μl ml(-1) lime oil at 70°C extended a period of zero mould growth on sedge to 18 weeks under moist conditions. Heat curing at 70°C best enhanced antifungal activity of lime oil against A. niger both in medium and on sedge. Heat curing of lime oil has potential to be used to enhance the antifungal safety of sedge products. © 2013 The Society for Applied Microbiology.

Liming Poultry Manures to Kill Pathogens and Decrease Soluble Phosphorus

International Nuclear Information System (INIS)

Maguire, R.; Hesterberg, D.; Gernat, A.; Anderson, K.; Wineland, M.; Grimes, J.

2006-01-01

Received for publication September 9, 2005. Stabilizing phosphorus (P) in poultry waste to reduce P losses from manured soils is important to protect surface waters, while pathogens in manures are an emerging issue. This study was conducted to evaluate CaO and Ca(OH) 2 for killing manure bacterial populations (pathogens) and stabilizing P in poultry wastes and to investigate the influence on soils following amendment with the treated wastes. Layer manure and broiler litter varying in moisture content were treated with CaO and Ca(OH) 2 at rates of 2.5, 5, 10, and 15% by weight. All treated wastes were analyzed for microbial plate counts, pH, and water-soluble phosphorus (WSP), while a few selected layer manures were analyzed by phosphorus X-ray absorption near edge structure (XANES). A loamy sand and a silt loam were amended with broiler litter and layer manure treated with CaO at rates of 0, 2.5, 5, 10, and 15% and soil WSP and pH were measured at times 1, 8, and 29 d. Liming reduced bacterial populations, with greater rates of lime leading to greater reductions; for example 10% CaO applied to 20% solids broiler litter reduced the plate counts from 793 000 to 6500 mL -1 . Liming also reduced the WSP in the manures by over 90% in all cases where at least 10% CaO was added. Liming the manures also reduced WSP in soils immediately following application and raised soil pH. The liming process used successfully reduced plate counts and concerns about P losses in runoff following land application of these limed products due to decreased WSP

Reconstruction of the pre-compactional thickness of the Zechstein Main Dolomite in northwest Poland

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Semyrka Grażyna

2015-12-01

Full Text Available Our reconstruction of the pre-compactional thickness of the Main Dolomite strata from the so-called Grotów Peninsula (northwest Poland was based on macroscopic observations of drill cores from three wells: Mokrzec-1, Sieraków-4 and Międzychód-5. These wells are located in various palaeogeographical zones of the Main Dolomite and cored rocks represent a range of microfacies. The amount of compactional reduction in thickness of the Main Dolomite was estimated by summing the total heights (Wst of all stylolites encountered in logs of these wells. For calculations, a generalised model of a drill core was developed, which embraced all types of stylolite seams present in the Main Dolomite succession studied. Also the method of stylolite dimensioning was demonstrated. The number of stylolites in the drill cores studied varied from 511 in the Sieraków-4 well to 1,534 in the Międzychód-5 well. In all cores studied low-amplitude macrostylolites predominated, but the reduction of thickness was controlled mostly by the low- and medium-amplitude macrostylolites. The largest number of stylolites was found in the grainstone/packstone microfacies. The turnout of stylolites depends of microfacies. The highest density of stylolites was documented in mudstones/wackestones (24 stylolites per metre of rock thickness and the lowest in boundstones (14 stylolites per metre of rock thickness. The low-amplitude stylolites appear most frequently in the mudstone/wackestone microfacies (15 stylolites per metre of rock thickness; in grainstones/packstones, rudstones/floatstones and boundstones middle-amplitude stylolites are rare (3 stylolites per metre of rock thickness. The degree of compaction of the Main Dolomite succession studied varied from 6 to 10%; hence, its calculated initial thickness also varied in the wells studied: from 41.3 m in the Sieraków-4 well to 56.9 m in the Mokrzec-1 well and to 97.1 m in the Międzychód-5 well. The volumes of reservoir

Classical Methods and Calculation Algorithms for Determining Lime Requirements

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André Guarçoni

Full Text Available ABSTRACT The methods developed for determination of lime requirements (LR are based on widely accepted principles. However, the formulas used for calculation have evolved little over recent decades, and in some cases there are indications of their inadequacy. The aim of this study was to compare the lime requirements calculated by three classic formulas and three algorithms, defining those most appropriate for supplying Ca and Mg to coffee plants and the smaller possibility of causing overliming. The database used contained 600 soil samples, which were collected in coffee plantings. The LR was estimated by the methods of base saturation, neutralization of Al3+, and elevation of Ca2+ and Mg2+ contents (two formulas and by the three calculation algorithms. Averages of the lime requirements were compared, determining the frequency distribution of the 600 lime requirements (LR estimated through each calculation method. In soils with low cation exchange capacity at pH 7, the base saturation method may fail to adequately supply the plants with Ca and Mg in many situations, while the method of Al3+ neutralization and elevation of Ca2+ and Mg2+ contents can result in the calculation of application rates that will increase the pH above the suitable range. Among the methods studied for calculating lime requirements, the algorithm that predicts reaching a defined base saturation, with adequate Ca and Mg supply and the maximum application rate limited to the H+Al value, proved to be the most efficient calculation method, and it can be recommended for use in numerous crops conditions.

Hydration of dicalcium silicate and diffusion through neo-formed calcium-silicate-hydrates at weathered surfaces control the long-term leaching behaviour of basic oxygen furnace (BOF) steelmaking slag.

Science.gov (United States)

Stewart, Douglas I; Bray, Andrew W; Udoma, Gideon; Hobson, Andrew J; Mayes, William M; Rogerson, Mike; Burke, Ian T

2018-04-01

Alkalinity generation and toxic trace metal (such as vanadium) leaching from basic oxygen furnace (BOF) steel slag particles must be properly understood and managed by pre-conditioning if beneficial reuse of slag is to be maximised. Water leaching under aerated conditions was investigated using fresh BOF slag at three different particle sizes (0.5-1.0, 2-5 and 10 × 10 × 20 mm blocks) and a 6-month pre-weathered block. There were several distinct leaching stages observed over time associated with different phases controlling the solution chemistry: (1) free-lime (CaO) dissolution (days 0-2); (2) dicalcium silicate (Ca 2 SiO 4 ) dissolution (days 2-14) and (3) Ca-Si-H and CaCO 3 formation and subsequent dissolution (days 14-73). Experiments with the smallest size fraction resulted in the highest Ca, Si and V concentrations, highlighting the role of surface area in controlling initial leaching. After ~2 weeks, the solution Ca/Si ratio (0.7-0.9) evolved to equal those found within a Ca-Si-H phase that replaced dicalcium silicate and free-lime phases in a 30- to 150-μm altered surface region. V release was a two-stage process; initially, V was released by dicalcium silicate dissolution, but V also isomorphically substituted for Si into the neo-formed Ca-Si-H in the alteration zone. Therefore, on longer timescales, the release of V to solution was primarily controlled by considerably slower Ca-Si-H dissolution rates, which decreased the rate of V release by an order of magnitude. Overall, the results indicate that the BOF slag leaching mechanism evolves from a situation initially dominated by rapid hydration and dissolution of primary dicalcium silicate/free-lime phases, to a slow diffusion limited process controlled by the solubility of secondary Ca-Si-H and CaCO 3 phases that replace and cover more reactive primary slag phases at particle surfaces.

Resetting of Mg isotopes between calcite and dolomite during burial metamorphism: Outlook of Mg isotopes as geothermometer and seawater proxy

Science.gov (United States)

Hu, Zhongya; Hu, Wenxuan; Wang, Xiaomin; Lu, Yizhou; Wang, Lichao; Liao, Zhiwei; Li, Weiqiang

2017-07-01

Magnesium isotopes are an emerging tool to study the geological processes recorded in carbonates. Calcite, due to its ubiquitous occurrence and the large Mg isotope fractionation associated with the mineral, has attracted great interests in applications of Mg isotope geochemistry. However, the fidelity of Mg isotopes in geological records of carbonate minerals (e.g., calcite and dolomite) against burial metamorphism remains poorly constrained. Here we report our investigation on the Mg isotope systematics of a dolomitized Middle Triassic Geshan carbonate section in eastern China. Magnesium isotope analysis was complemented by analyses of Sr-C-O isotopic compositions, major and trace element concentrations, and petrographic and mineralogical features. Multiple lines of evidence consistently indicated that post-depositional diagenesis of carbonate minerals occurred to the carbonate rocks. Magnesium isotope compositions of the carbonate rocks closely follow a mixing trend between a high δ26Mg dolomite end member and a low δ26Mg calcite end member, irrespective of sample positions in the section and calcite/dolomite ratio in the samples. By fitting the measured Mg isotope data using a two-end member mixing model, an inter-mineral Δ26Mgdolomite-calcite fractionation of 0.72‰ was obtained. Based on the experimentally derived Mg isotope fractionation factors for dolomite and calcite, a temperature of 150-190 °C was calculated to correspond to the 0.72‰ Δ26Mgdolomite-calcite fractionation. Such temperature range matches with the burial-thermal history of the local strata, making a successful case of Mg isotope geothermometry. Our results indicate that both calcite and dolomite had been re-equilibrated during burial metamorphism, and based on isotope mass balance of Mg, the system was buffered by dolomite in the section. Therefore, burial metamorphism may reset Mg isotope signature of calcite, and Mg isotope compositions in calcite should be dealt with caution in

76 FR 82295 - Central Power & Lime LLC; Notice of Filing

Science.gov (United States)

2011-12-30

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket Nos. EL12-18-000; QF82-207-007] Central Power & Lime LLC; Notice of Filing December 23, 2011. Take notice that on December 22, 2011, Central Power & Lime LLC, pursuant to sections 18 CFR 292.205(c) and 385.207 of the Federal Energy...

A nano approach to consolidation of degraded historic lime mortars

Czech Academy of Sciences Publication Activity Database

Drdácký, Miloš; Slížková, Zuzana; Ziegenbalg, G.

2009-01-01

Roč. 8, č. 2 (2009), s. 13-22 ISSN 1662-5250 R&D Projects: GA ČR(CZ) GA103/06/1609 Institutional research plan: CEZ:AV0Z20710524 Keywords : lime water * calcium hydroxide nanosuspension * lime mortar Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 0.571, year: 2009

Utilization of slaked lime for the regulation of pH value in the process of copper

Directory of Open Access Journals (Sweden)

Petković Aleksandar V.

2009-01-01

Full Text Available The investigations of used lime at plant from company Messer-Tehnogas, Belgrade, were in the aim to improvement technologically results from flotation concentration of copper minerals in flotation plant Veliki Krivelj. This paper shows usage of slaked lime, which is waste in the process of technical gas production, for regulation of pH value in the process of copper minerals flotation concentration. It is important to point out that slaked lime is a waste material that is not dangerous. Preparation and dosage includes preparation procedures, which enable introduction into flotation process with the aim of achieving better results. Lime from Limekiln Zagrađe is brought into four storage places in flotation. Volume of each storage place is 80 m3. Lime in pieces from storage place is added by airbladders on transportation line and by system of transportation lines lime gets to the ball mill. At the mill entrance water is added and then follows lime grinding. Milk glass of lime thus prepared goes to the pump basket from where is transported by pipeline to conditioner, and then by manual and (or automatic valves it is dosed to the flotation concentration of copper minerals process. Prospect of advancement and rationalization of the used lime in flotation plant Bor, Veliki Krivelj and Majdanpek as well as a way to link different branches of industry was demonstrated. Total cost of lime supplying, transporting, preparation and distribution related slaked lime is lower for 2.955 din/kg. Particularly, using lime from Messer in content of 2.1 g/l value of pH 11.82 is possible to obtain.

Subsurface example of a dolomitized middle Guadalupian (Permian) reef from west Texas

Energy Technology Data Exchange (ETDEWEB)

Longacre, S.A.

1983-01-01

A middle Guadalupian organic buildup was cored in the North McElroy Unit (NMU No. 3713 well) in Upton County, W. Texas. Fusulinid control indicates the buildup is equivalent to the Goat Seep reef that crops out in the Guadalupe Mt. The organic buildup at North McElroy consists of boundstones and associated flank grainstones. The reef biota is dominated by ramose and encrusting bryozoans, numerous types of calcareous sponges, the problematic encrusting organism Tubiphytes, encrusting algae, crinoids, brachiopods, and trilobites. Among the more significant aspects of diagenesis are mechanical degradation and biologic degradation, leaching, gypsum-anhydrite transformations, cementation, replacement of all calcite by dolomite, cementation and replacement by baroque dolomite, fracturing, and replacement of carbonate by anhydrite. 17 references.

Produtividade e qualidade fisiológica de sementes de aveia preta em função da calagem superficial em plantio direto = Black oat yield and seed physiologic quality under superficial lime application in no tillage system

Directory of Open Access Journals (Sweden)

Tiago Roque Benetoli da Silva

2006-04-01

Full Text Available Com o objetivo de avaliar a produtividade e a qualidade fisiológica de sementes de aveia preta em razão da aplicação superficial de calcário em plantio direto, foi realizado um experimento em Botucatu, Estado de São Paulo, sob condições de sequeiro. O delineamento experimental foi o de blocos casualizados, com quatro repetições, em que os tratamentos foram constituídos por aplicação superficial de doses de calcário dolomítico (D0 = zero – sem aplicação de calcário; D1 = 1,8 t ha-1 – quantidade de calcário para elevar a saturação por bases a 54%; D2 = 3,6 t ha-1 – quantidade de calcário para elevar a saturação por bases a 68% e D3 = 5,4 t ha-1 – quantidade de calcário para elevar a saturação por bases a 80%, realizada em outubro de 2002. A cultura da aveia preta, cultivar Comum, foi semeada em abril de 2004, no segundo ano após a rotação milheto (primavera, feijão (verão e aveia preta (outono e inverno. Com os resultados obtidos, observou-se ganho de produtividade com a aplicação superficial de calcário, porém sem influenciar a qualidade fisiológica das sementes de aveia preta.The experiment carried out in Botucatu, São Paulo State, Brazil, in dry conditions, aiming to evaluate the yield and physiologic quality of black oat seeds, under superficial liming in no tillage system. A randomized complete block design was used, with four replications. The treatments were superficial application of different dolomitic lime rates (R0 = zero – without lime; R1 = 1.8 t ha-1 – lime to increase the base saturation at 54%; R2 = 3.6 t ha-1 – lime to increase the base saturation at 68%, and R3 = 5.4 t ha-1 – lime to increase the base saturation at 80%, in October 2002. The blackoat Common cultivar was sowed in April 2004, in second year, after the crop rotation of millet (spring, common bean (summer, black oat (autumn/winter. The results showed that the black oat physiologic quality seed was not affected by

Admixture of lime in connection with deep rotary cultivation for short rotation energy forest

Energy Technology Data Exchange (ETDEWEB)

Danfors, B; Stambeck, A; Aasberg, G

1985-01-01

Spaghnum soils, which could be used for production of short rotation energy forests (Salix), require lime for the adjustment of the pH-level to obtain production at acceptable levels. It is necessary that the lime is distributed uniformly in the soil profile to a depth of at least 40-50 cm. The investigation has studied three methods of spreading and incorporating lime in the uppermost layer of soil. The first method concerned ploughing of peat soil with a conventional agricultural plough, the second method concerned rotovation with an agricutural rotovator to maximally 20 cm depth. In both cases the lime has been spread with a centrifugal broadcaster before the soil tillage. The third method implied simultaneous spreading of the lime and rotovation of the peat to a depth of maximally 50 cm, JTI has built and constructed a machine for this purpose. Ploughing as the only method of soil tillage of peat soils before planting of short rotation energy forests is rejected for two reasons. 1. Certain peat soils which have such mechanical properties that they immediately completely clog a plough. 2. The deficient distribution of lime in the ploughed layer. Rotovation with an agricultural rotovator has been done with good results. The delivery of lime in connection with the rotovation works well provided that the lime is dry. The peat is efficiently disintegrated and the lime gets a sufficiently uniform admixture. The cultivation depth, 40-50 cm, appears to be sufficient for the Salix plants to cope with the water supply during the summer. Limitations which should be discussed concern the cost of such an intensive and deep tillage of the peat.

Nutrient leaching potential following application of papermill lime-sludge to an acidic clay soil

Directory of Open Access Journals (Sweden)

S. C. Vettorazzo

2001-09-01

Full Text Available This experiment was carried out under greenhouse conditions with soil pots during 210 days, to evaluate the effect of calcitic papermill lime-sludge application (at the rates 0, 773, 1.547, and 2.320 mg kg-1 or respective equivalents to control, 2, 4, and 6 t ha-1, on chemical composition of soil leachate and its effects on eucalypt growth and yield. Highest soil leachate pH, SO4, and Na concentrations occurred in the 4 and 6 t ha-1 treatments. Soil leachate nitrate concentrations decreased with increasing lime-sludge rate. Soil leachate phosphate remained low (below the detection limit in all treatments until 120 days, while the concentration increased in the lime-sludge treatments at 210 days (last sampling in about 600 mg L-1. Lime-sludge decreased leachate Mg concentration, but had no significant effect among rates. Soil leachate Ca, K, B, Cu, Fe, and Zn did not change significantly for any lime-sludge application rates. The maximum NO3, Ca, Mg, K, and Na concentrations in the soil leachate occurred at 60 days after lime-sludge application (leaching equivalent to 1 pore volume, but for pH and SO4, the maximum occurred at 210 days (leaching equivalent to 4 pore volumes. Lime-sludge application decreased the concentration of exchangeable Al in the soil. Plant diameter growth and dry matter yield were increased with increasing lime-sludge rate. Beneficial effects on mineral nutrition (P, K, Ca, B, and Zn of eucalypts were also obtained by the application of 4 and 6 t ha-1 of lime-sludge.

Experimental Effects of Lime Application on Aquatic Macrophytes: 2. Growth Response Versus Treatment Time and Lime Concentration

National Research Council Canada - National Science Library

James, William F; Barko, John W

2006-01-01

This research investigated the effects of applying lime (as calcium hydroxide; Ca(OH)2) either early or later in the life cycle on the growth, survivorship, and reproductive success of Sago Pondweed...

Common Ion Effects In Zeoponic Substrates: Dissolution And Cation Exchange Variations Due to Additions of Calcite, Dolomite and Wollastonite

Science.gov (United States)

Beiersdorfer, R. E.; Ming, D. W.; Galindo, C., Jr.

2003-01-01

c1inoptilolite-rich tuff-hydroxyapatite mixture (zeoponic substrate) has the potential to serve as a synthetic soil-additive for plant growth. Essential plant macro-nutrients such as calcium, phosphorous, magnesium, ammonium and potassium are released into solution via dissolution of the hydroxyapatite and cation exchange on zeolite charged sites. Plant growth experiments resulting in low yield for wheat have been attributed to a Ca deficiency caused by a high degree of cation exchange by the zeolite. Batch-equilibration experiments were performed in order to determine if the Ca deficiency can be remedied by the addition of a second Ca-bearing, soluble, mineral such as calcite, dolomite or wollastonite. Variations in the amount of calcite, dolomite or wollastonite resulted in systematic changes in the concentrations of Ca and P. The addition of calcite, dolomite or wollastonite to the zeoponic substrate resulted in an exponential decrease in the phosphorous concentration in solution. The exponential rate of decay was greatest for calcite (5.60 wt. % -I), intermediate for wollastonite (2.85 wt.% -I) and least for dolomite (1.58 wt.% -I). Additions of the three minerals resulted in linear increases in the calcium concentration in solution. The rate of increase was greatest for calcite (3.64), intermediate for wollastonite (2.41) and least for dolomite (0.61). The observed changes in P and Ca concentration are consistent with the solubilities of calcite, dolomite and wollastonite and with changes expected from a common ion effect with Ca. Keywords: zeolite, zeoponics, common-ion effect, clinoptilolite, hydroxyapatite

Effect of Lime on characteristics of consolidation, strength, swelling and plasticity of fine grained soil

Science.gov (United States)

Estabragh, A. R.; Bordbar, A. T.; Parsaee, B.; Eskandari, Gh.

2009-04-01

Using Lime as an additive material to clayey soil is one of the best effective technique in building the soil structures to get some purposes such as soil stabilization, soil reinforcement and decreasing soil swelling. In this research the effect of Lime on geotechnical characteristics of a clayey soil was investigated. Soil specimen types used in this study were consisted of clayey soil as the control treatment and clay mixed with different weight fractions of lime, 4, 6, 8 & 10 percent. Some experiments such as CBR, atterburg limits, compaction, consolidation and swelling was conducted on specimens. Results revealed that adding lime to soil would change its physical and mechanical properties. Adding lime increase the compression strength and consolidation coefficient and decrease swelling potential and maximum dry density. According to the results, Atterburg experiments show that presence of lime in soil increase the liquid limit of low plasticity soil and decrease the liquid limit of high plasticity soil, but totally it decreases the plasticity index of soils. Key words: soil stabilization, lime, compression strength, swelling, atterburg limits, compaction

Arsenic immobilization by calcium-arsenic precipitates in lime treated soils

International Nuclear Information System (INIS)

Moon, Deok Hyun; Dermatas, Dimitris; Menounou, Nektaria

2004-01-01

Lime-based stabilization/solidification (S/S) can be an effective remediation alternative for the immobilization of arsenic (As) in contaminated soils and sludges. However, the exact immobilization mechanism has not been well established. Based on previous research, As immobilization could be attributed to sorption and/or inclusion in pozzolanic reaction products and/or the formation of calcium-arsenic (Ca-As) precipitates. In this study, suspensions of lime-As and lime-As-kaolinite were studied in an attempt to elucidate the controlling mechanism of As immobilization in lime treated soils. Aqueous lime-As suspensions (slurries) with varying Ca/As molar ratios (1:1, 1.5:1, 2:1, 2.5:1 and 4:1) were prepared and soluble As concentrations were determined. X-Ray diffraction (XRD) analyses were used to establish the resulting mineralogy of crystalline precipitate formation. Depending on the redox state of the As source, different As precipitates were identified. When As (III) was used, the main precipitate formation was Ca-As-O. With As(V) as the source, Ca 4 (OH) 2 (AsO 4 ) 2 ·4H 2 O formed at Ca/As molar ratios greater than 1:1. A significant increase in As (III) immobilization was observed at Ca/As molar ratios greater than 1:1. Similarly, a substantial increase in As (V) immobilization was noted at Ca/As molar ratios greater than or equal to 2.5:1. This observation was also confirmed by XRD. Lime-As-kaolinite slurries were also prepared at different Ca/As molar ratios. These slurries were used to specifically investigate the possibility of forming pozzolanic reaction products. Such products would immobilize As by sorption and/or inclusion along with the formations of different As precipitates. Toxicity Characteristic Leaching Procedure (TCLP) tests were used to evaluate As leachability in these slurries. XRD analyses revealed no pozzolanic reaction product formation. Instead, As immobilization was found to be precipitation controlled. The same Ca-As precipitate, Ca

Acidic deposition: State of science and technology. Report 15. Liming acidic surface waters. Final report

International Nuclear Information System (INIS)

Olem, H.; Thornelof, E.; Sandoy, S.; Schreiber, R.K.

1990-09-01

The document describes the science and technology of aquatic liming--a method for improving the water quality of acidic surface waters to restore or enhance fisheries. The report is a comprehensive compilation of years of research in North America and Europe by dozens of scientists. Several mitigation technologies--including those that have only been proposed--are critically evaluated along with the effects of liming on water chemistry and aquatic biota. Through these evaluations, the state of the science and technology of aquatic liming is identified for the reader. Whole-lake liming is now recognized as a valuable management tool for acidic surface waters and their fisheries. However, some liming technologies are considered experimental and will need further evaluation. Distinctions between technologies are included--as is the distinction between liming acidic surface waters and reducing acidifying emissions

Characterization of cutting soda-lime glass sludge for the formulation of red ceramic products

International Nuclear Information System (INIS)

Filogonio, P.H.C.; Reis, A.S.; Louzada, D.M.; Della, V.P.

2014-01-01

Considering previous works that have demonstrated the feasibility of soda-lime glass incorporation into red ceramics, this paper aims to determine the potential for incorporation of cutting soda-lime glass sludge in red ceramic manufacturing. Therefore, the waste was characterized by X-ray fluorescence, X-ray diffraction, particle size distribution and thermal behavior. The results confirm the chemical and mineralogical similarity between waste and soda-lime glass. Because of this similarity, it is concluded that the soda-lime glass waste has the capability to be used in the manufacturing of red ceramics. (author)

Study of lime vs. no lime in cold in-place recycled asphalt concrete pavements : final report.

Science.gov (United States)

1991-09-01

The resilient characteristics of cold in-place recycled asphalt concrete with and without lime were examined. Six core samples were obtained from a site two months after construction; six months later, six additional core samples were obtained from t...

Experimental observation of permeability changes in dolomite at CO2 sequestration conditions.

Science.gov (United States)

Tutolo, Benjamin M; Luhmann, Andrew J; Kong, Xiang-Zhao; Saar, Martin O; Seyfried, William E

2014-02-18

Injection of cool CO2 into geothermally warm carbonate reservoirs for storage or geothermal energy production may lower near-well temperature and lead to mass transfer along flow paths leading away from the well. To investigate this process, a dolomite core was subjected to a 650 h, high pressure, CO2 saturated, flow-through experiment. Permeability increased from 10(-15.9) to 10(-15.2) m(2) over the initial 216 h at 21 °C, decreased to 10(-16.2) m(2) over 289 h at 50 °C, largely due to thermally driven CO2 exsolution, and reached a final value of 10(-16.4) m(2) after 145 h at 100 °C due to continued exsolution and the onset of dolomite precipitation. Theoretical calculations show that CO2 exsolution results in a maximum pore space CO2 saturation of 0.5, and steady state relative permeabilities of CO2 and water on the order of 0.0065 and 0.1, respectively. Post-experiment imagery reveals matrix dissolution at low temperatures, and subsequent filling-in of flow passages at elevated temperature. Geochemical calculations indicate that reservoir fluids subjected to a thermal gradient may exsolve and precipitate up to 200 cm(3) CO2 and 1.5 cm(3) dolomite per kg of water, respectively, resulting in substantial porosity and permeability redistribution.

Self-healing of lime based mortars: Microscopy observations on case studies

NARCIS (Netherlands)

Lubelli, B.; Nijland, T.G.; Hees, R.P.J. van

2011-01-01

Lime mortars have, up to a certain extent, a self-healing capacity which may contribute to their durability. Self-healing in lime mortars consists of a process of dissolution, transport and re-precipitation of calcium compounds to heal cracks and fissures. The spontaneous occurrence of self-healing

Self-healing of lime based mortars : Microscopy observations on case studies

NARCIS (Netherlands)

Lubelli, B.; Nijland, T.G.; Van Hees, R.P.J.

2011-01-01

Lime mortars have, up to a certain extent, a self-healing capacity which may contribute to their durability. Self-healing in lime mortars consists of a process of dissolution, transport and re-precipitation of calcium compounds to heal cracks and fissures. The spontaneous occurrence of self-healing

Adubos fosfatados na absorção de fósforo pela soja em presença e ausência de calagem Effect of phosphate fertilizers and liming on phosphorus uptake by soybeans

Directory of Open Access Journals (Sweden)

Ondino Cleante Bataglia

1984-01-01

Full Text Available Num experimento conduzido em São Simão (SP durante três anos consecutivos, em um latossolo roxo de textura média, anteriormente sob vegetação de cerrado, estudou-se o efeito da aplicação de fosfato-de-araxá, hiperfosfato, termofosfato (Yoorin e superfosfato triplo em presença e ausência de calagem, sobre o crescimento, produtividade e absorção de nutrientes pela soja cultivar Santa-Rosa. Os dados evidenciaram a importância dos nutrientes acompanhantes de fósforo dos adubos fosfatados, especialmente do cálcio, sobre o crescimento, produção de grãos e absorção de fósforo pela parte aérea da soja. Na presença de calagem, não houve diferença marcante entre os adubos sobre a produtividade e absorção do fósforo. Na sua ausência, os adubos menos solúveis, aplicados em maiores quantidades e, portanto, levando grandes quantidades de cálcio, mostraram efeitos residuais melhores que os fosfatados mais solúveis. A produtividade com a aplicação dos fosfatos menos solúveis no terceiro ano de plantio sem calagem mostrou boa correlação com a absorção de cálcio, magnésio, fósforo e com a relação Ca/Mn das folhas.One experiment was conducted during three successive growing seasons in São Simão, State of São Paulo, Brazil, to test the effect of different phosphates and liming on the uptake of phosphorus by soybeans. The phosphates were: >- rock phosphate, hyperphosphate, termophosphate (Yoorin and triple superphosphate, at rates of 100, 200 and 400kg/ha of water or 2% citric acid soluble P2O5 and a common control without phosphorus. The phosphates were broadcasted over limed or non limed plots. Dolomitic lime was applied at rates of 2500kg/ha before the first and third planting. The cultivar used was 'Santa Rosa'. Field data demonstrated the importance of the nutrients, specially calcium, carried by the phosphate together with phosphorus, on growth, grain productivity and phosphorus uptake by soybeans. In the

Influence of natural pozzolana and lime additives on the temporal variation of soil compaction and shear strength

Science.gov (United States)

Harichane, Khelifa; Ghrici, Mohamed; Missoum, Hanifi

2011-06-01

Soil stabilization has been practiced for quite some time by adding mixtures, such as cement, lime and fly ash. The additives of lime (L), natural pozzolana (NP) or a combination of both were investigated here on the impact on the temporal variation of geotechnical characteristics of two cohesive soils. Lime and natural pozzolana were added at the content of 0-8% and 0-20%, respectively. The soil specimens were cured for 1, 7, 28 and 90 days and then tested for shear strength. Our data show that a combination of lime with natural pozzolana causes the increase in the maximum dry density but the decrease in the optimum moisture content in the gray soil, and vice verse in the red soil. The shear stress of both cohesive soils stabilized with lime or with the combination of lime and natural pozzolana was found to increase with time. The cohesion and the internal friction angle in lime-added samples were demonstrated to increase with time. The combination of lime with natural pozzolana exhibits a significant effect on the enhancement of the cohesion and the internal friction angle at later stages. The lime-natural pozzolana combination appears to produce higher shear parameters than lime or natural pozzolana used alone.

Simple, simultaneous gravimetric determination of calcite and dolomite in calcareous soils

Science.gov (United States)

Literature pertaining to determination of calcite and dolomite is not modern and describes slow methods that require expensive specialized apparatus. The objective of this paper was to describe a new method that requires no specialized equipment. Linear regressions and correlation coefficients for...

Nanosecond (ns) laser transfer of silver nanoparticles from silver-exchanged soda-lime glass to transparent soda-lime glass and shock waves formation

International Nuclear Information System (INIS)

Sow, Mohamed Chérif; Blondeau, Jean-Philippe; Sagot, Nadine; Ollier, Nadège; Tite, Teddy

2015-01-01

Highlights: • Silver nanoparticles growth by nanosecond laser irradiation of silver exchanged soda-lime glasses. • Silver nanoparticles transfer. • Nanosecond laser induced shock waves formation on glass. - Abstract: In this contribution, we showed for the first time in our knowledge a single-step process for silver clusters and nanoparticles growth and transfer from silver-exchanged soda-lime glass to un-exchanged soda-lime glass (transparent glass in visible and NIR domain) by nanosecond (ns) laser irradiation. The transferred silver nanoparticles in transparent glass are strongly linked to the glass surface. In addition, we point out the formation of shock waves, with selective silver clustering on the top wave. This technique provides an alternative and simple way to obtain metallic nanoparticles in different media which can be traversed by laser wavelength used. Moreover, this experiment is made at room temperature and air environment. It is worth noting that our technique requires a glass previously doped with the corresponding silver ions

Impact of lime treated soils performance on design of earthfill dikes

Directory of Open Access Journals (Sweden)

Nerincx Nicolas

2016-01-01

Full Text Available Nowadays soil treatment with lime in civil engineering is widespread in many countries on all continents, within several construction fields. The interest of the hydraulic works community regarding this technique is currently growing. It has been indeed shown during the last decade that appropriate treatment technologies provide lime treated soils with high level properties such as excellent homogeneity, low permeability, internal and external erosion resistance and mechanical stability. Those have been shown in laboratory and for some properties with full scale experiments. The so conferred soil properties can lead to innovative earthfill dams and dikes designs by addressing some of the typical designer’s problems, such as stability, watertightness, internal erosion, surface protection and flood control. However, lime treated soil external erosion resistance is still to be quantified in the field for proper designing and dimensioning of lime treated soil external erosion protection or spillways. With this purpose, an experimental earthfill dike has been built along the river Vidourle (France in July 2015, in the frame of the French R&D program “DigueELITE”. This 50 m long and 3,5 m high dike is made of lime treated silt and is provided with sensors (succion, water content and temperature and piezometer in order to be monitored. It will also be tested against surface erosion. The final objective of this R&D program is to provide guidelines for designing innovative overflow resistant earthfill dikes. This article describes the performance reached by lime treated soils and associated design requirements and application; the experimental dike construction and lessons learned; the monitoring program; the dike design perspectives opened by soil treatment.

Investigation of Hydraulic Binding Characteristics of Lime Based Mortars Used in Historical Masonry Structures

Science.gov (United States)

Binal, Adil

2017-10-01

In the historic masonry structures, hard and large rock fragments were used as the construction materials. The hydraulic binder material prepared to keep this used material in its entirety is a different material than the cement used today. Khorasan mortar made by using aggregate and lime exhibits a more flexible structure than the concrete. This feature allows the historic building to be more durable. There is also a significant industrial value because of the use of Khorasan mortar in the restoration of historic masonry structures. Therefore, the calculation of the ideal mixture of Khorasan mortar and the determination of its mechanical and physical properties are of great importance regarding preserving historic buildings. In this study, the mixtures of different lime and brick fractions were prepared. It was determined that Khorasan mortar shows the highest compressive strength in mixtures with water/lime ratio of 0.55 and lime/aggregate ratio of 0.66. By keeping the mixing ratio constant, it was observed that the strengths of the samples kept in the humidity chamber for different curing times increased day by day. The early strength values of samples with the high lime/aggregate ratio (l/a: 0.83) were higher than those with the low lime/aggregate ratio (l/a: 0.5). For the samples with low lime/aggregate ratio, there was an increase in the strength values depending on the curing period. As the cure duration increases, a chemical reaction takes place between the lime and the brick fracture, and as a result of this reaction, the strength values are increased.

Calcium hydroxide poisoning

Science.gov (United States)

Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

REMOVAL OF BERYLLIUM FROM DRINKING WATER BY CHEMICAL COAGULATION AND LIME SOFTENING

Science.gov (United States)

The effectiveness of conventional drinking water treatment and lime softening was evaluated for beryllium removal from two drinking water sources. ar test studies were conducted to determine how common coagulants (aluminum sulfate and ferric chloride and lime softening performed ...

Direct measurement of methane hydrate composition along the hydrate equilibrium boundary

Science.gov (United States)

Circone, S.; Kirby, S.H.; Stern, L.A.

2005-01-01

The composition of methane hydrate, namely nW for CH 4??nWH2O, was directly measured along the hydrate equilibrium boundary under conditions of excess methane gas. Pressure and temperature conditions ranged from 1.9 to 9.7 MPa and 263 to 285 K. Within experimental error, there is no change in hydrate composition with increasing pressure along the equilibrium boundary, but nW may show a slight systematic decrease away from this boundary. A hydrate stoichiometry of n W = 5.81-6.10 H2O describes the entire range of measured values, with an average composition of CH4??5.99(??0.07) H2O along the equilibrium boundary. These results, consistent with previously measured values, are discussed with respect to the widely ranging values obtained by thermodynamic analysis. The relatively constant composition of methane hydrate over the geologically relevant pressure and temperature range investigated suggests that in situ methane hydrate compositions may be estimated with some confidence. ?? 2005 American Chemical Society.

A Comparison between Lime and Alkaline Hydrogen Peroxide Pretreatments of Sugarcane Bagasse for Ethanol Production

Science.gov (United States)

Rabelo, Sarita C.; Filho, Rubens Maciel; Costa, Aline C.

Pretreatment procedures of sugarcane bagasse with lime (calcium hydroxide) or alkaline hydrogen peroxide were evaluated and compared. Analyses were performed using 2 × 2 × 2 factorial designs, with pretreatment time, temperature, and lime loading and hydrogen peroxide concentration as factors. The responses evaluated were the yield of total reducing sugars (TRS) and glucose released from pretreated bagasse after enzymatic hydrolysis. Experiments were performed using the bagasse as it comes from an alcohol/ sugar factory and bagasse in the size range of 0.248 to 1.397 mm (12-60 mesh). The results show that when hexoses and pentoses are of interest, lime should be the pretreatment agent chosen, as high TRS yields are obtained for nonscreened bagasse using 0.40 g lime/g dry biomass at 70 °C for 36 h. When the product of interest is glucose, the best results were obtained with lime pretreatment of screened bagasse. However, the results for alkaline peroxide and lime pretreatments of nonscreened bagasse are not very different.

An introduction to LIME 1.0 and its use in coupling codes for multiphysics simulations.

Energy Technology Data Exchange (ETDEWEB)

Belcourt, Noel; Pawlowski, Roger Patrick; Schmidt, Rodney Cannon; Hooper, Russell Warren

2011-11-01

LIME is a small software package for creating multiphysics simulation codes. The name was formed as an acronym denoting 'Lightweight Integrating Multiphysics Environment for coupling codes.' LIME is intended to be especially useful when separate computer codes (which may be written in any standard computer language) already exist to solve different parts of a multiphysics problem. LIME provides the key high-level software (written in C++), a well defined approach (with example templates), and interface requirements to enable the assembly of multiple physics codes into a single coupled-multiphysics simulation code. In this report we introduce important software design characteristics of LIME, describe key components of a typical multiphysics application that might be created using LIME, and provide basic examples of its use - including the customized software that must be written by a user. We also describe the types of modifications that may be needed to individual physics codes in order for them to be incorporated into a LIME-based multiphysics application.

Glass-Forming Ability of Soda Lime Borate Liquids

DEFF Research Database (Denmark)

Zheng, Qiuju; Mauro, J.C.; Smedskjær, Morten Mattrup

2012-01-01

We investigate the composition dependence of glass-forming ability (GFA) of a series of iron-containing soda lime borate liquids by substituting Na2O for B2O3. We have characterized GFA by measuring the glass stability against crystallization using a differential scanning calorimeter (DSC......). The results show that the GFA decreases when substituting Na2O for B2O3. Moreover, we find that there is no direct link between the kinetic fragility and GFA for the soda lime borate series studied herein. We have also discovered and clarified a striking thermal history dependence of the glass stability...

Utilization of red mud and Pb/Zn smelter waste for the synthesis of a red mud-based cementitious material.

Science.gov (United States)

Li, Yuan-Cheng; Min, Xiao-Bo; Ke, Yong; Chai, Li-Yuan; Shi, Mei-Qing; Tang, Chong-Jian; Wang, Qing-Wei; Liang, Yan-Jie; Lei, Jie; Liu, De-Gang

2018-02-15

A new method in which Pb/Zn smelter waste containing arsenic and heavy metals (arsenic sludge), red mud and lime are utilized to prepare red mud-based cementitious material (RCM) is proposed in this study. XRD, SEM, FTIR and unconfined compressive strength (UCS) tests were employed to assess the physicochemical properties of RCM. In addition, ettringite and iron oxide-containing ettringite were used to study the hydration mechanism of RCM. The results show that the UCS of the RCM (red mud+arsenic sludge+lime) was higher than that of the binder (red mud+arsenic sludge). When the mass ratio of m (binder): m (lime) was 94:6 and then maintained 28days at ambient temperature, the UCS reached 12.05MPa. The red mud has potential cementitious characteristics, and the major source of those characteristics was the aluminium oxide. In the red mud-arsenic sludge-lime system, aluminium oxide was effectively activated by lime and gypsum to form complex hydration products. Some of the aluminium in ettringite was replaced by iron to form calcium sulfoferrite hydrate. The BCR and leaching toxicity results show that the leaching concentration was strongly dependent on the chemical speciation of arsenic and the hydration products. Therefore, the investigated red mud and arsenic sludge can be successfully utilized in cement composites to create a red mud-based cementitious material. Copyright © 2017 Elsevier B.V. All rights reserved.

Gas hydrate in nature

Science.gov (United States)

Ruppel, Carolyn D.

2018-01-17

Gas hydrate is a naturally occurring, ice-like substance that forms when water and gas combine under high pressure and at moderate temperatures. Methane is the most common gas present in gas hydrate, although other gases may also be included in hydrate structures, particularly in areas close to conventional oil and gas reservoirs. Gas hydrate is widespread in ocean-bottom sediments at water depths greater than 300–500 meters (m; 984–1,640 feet [ft]) and is also present in areas with permanently frozen ground (permafrost). Several countries are evaluating gas hydrate as a possible energy resource in deepwater or permafrost settings. Gas hydrate is also under investigation to determine how environmental change may affect these deposits.

Lime Kiln Modeling. CFD and One-dimensional simulations

Energy Technology Data Exchange (ETDEWEB)

Svedin, Kristoffer; Ivarsson, Christofer; Lundborg, Rickard

2009-03-15

The incentives for burning alternative fuels in lime kilns are growing. An increasing demand on thorough investigations of alternative fuel impact on lime kiln performance have been recognized, and the purpose of this project has been to develop a lime kiln CFD model with the possibility to fire fuel oil and lignin. The second part of the project consists of three technical studies. Simulated data from a one-dimensional steady state program has been used to support theories on the impact of biofuels and lime mud dryness. The CFD simulations was carried out in the commercial code FLUENT. Due to difficulties with the convergence of the model the calcination reaction is not included. The model shows essential differences between the two fuels. Lignin gives a different flame shape and a longer flame length compared to fuel oil. Mainly this depends on how the fuel is fed into the combustion chamber and how much combustion air that is added as primary and secondary air. In the case of lignin combustion the required amount of air is more than in the fuel oil case. This generates more combustion gas and a different flow pattern is created. Based on the values from turbulent reaction rate for the different fuels an estimated flame length can be obtained. For fuel oil the combustion is very intense with a sharp peak in the beginning and a rapid decrease. For lignin the combustion starts not as intense as for the fuel oil case and has a smoother shape. The flame length appears to be approximately 2-3 meter longer for lignin than for fuel oil based on turbulent reaction rate in the computational simulations. The first technical study showed that there are many benefits of increasing dry solids content in the lime mud going into a kiln such as increased energy efficiency, reduced TRS, and reduced sodium in the kiln. However, data from operating kilns indicates that these benefits can be offset by increasing exit gas temperature that can limit kiln production capacity. Simulated

77 FR 45715 - Application of Key Lime Air Corporation for Commuter Authority

Science.gov (United States)

2012-08-01

... DEPARTMENT OF TRANSPORTATION Office of the Secretary [Docket DOT-OST-2009-0116] Application of Key Lime Air Corporation for Commuter Authority AGENCY: Department of Transportation. ACTION: Notice of... Lime Air Corporation fit, willing, and able, and awarding it a Commuter Air Carrier Authorization...

Belowground ectomycorrhizal fungal communities respond to liming in three southern Swedish coniferous forest stands

DEFF Research Database (Denmark)

Kjøller, Rasmus; Clemmensen, Karina

2009-01-01

In this study we report on changes in the belowground ectomycorrhizal fungal communities in southern Swedish coniferous forests as a consequence of liming with 3-7 ton limestone per hectare 16 years prior to the study. A total of 107 ectomycorrhizal fungi were identified from 969 independently...... sampled root tips by sequencing the internal transcribed spacer region of the ribosomal DNA. Forty, 59 and 51 species were identified in three pine and spruce forests. Within all sites only about 25% of the species overlapped between the limed and the reference areas. However, the most abundant species...... were often found in both limed and reference plots and 60-70% of the root tips at each site were colonised by species occurring in both limed and reference plots. Across all three sites, fungal species belonging to the genus Tylospora and the order Pezizales became significantly more frequent in limed...

California Bearing Ratio (CBR) test on stabilization of clay with lime addition

Science.gov (United States)

Hastuty, I. P.; Roesyanto; Limbong, M. N.; Oberlyn, S. J.

2018-02-01

Clay is a type of soil with particles of certain minerals giving plastic properties when mixed with water. Soil has an important role in a construction, besides as a building material in a wide variety of civil engineering works, soil is also used as supporting foundation of the building. Basic properties of clay are rock-solid in dry and plastic with medium water content. In high water content, clay becomes sticky like (cohesive) and soften. Therefore, clay stabilization is necessary to repair soil’s mechanical properties. In this research, lime is use as a stabilizer that contains the Ca+ element to bond bigger particles. Lime used is slaked lime Ca(OH)2. Clay used has liquid limitation (LL) value of 47.33%, plasticity index of 29.88% and CBR value 6.29. The results explain about 10% lime mixture variation gives the optimum stabilized clay with CBR value of 8.75%.

Origin of dolomites in a downslope biostrome, Jefferson Formation (Frasnian), central Idaho: evidence from REE patterns, stable isotopes, and petrography

Energy Technology Data Exchange (ETDEWEB)

Dorobek, S.L.

1987-08-01

A completely dolomitized coral-stromatoporoid biostrome occurs at the top of the Dark Dolomite member of the Jefferson Formation (Frasnian) at Grandview Canyon, Lost River Range, central Idaho. The biostrome overlies a thick sequence of dolostones that were deposited in slope to deep ramp settings. The biostrome, therefore, formed in an open marine setting after shallowing of deep water environments. Zoned dolospar cement fills dissolution vugs and tectonic fractures. Stable isotopes for zoned dolospar are -13.1 to -6.5 per thousand delta/sup 18/O (average - 11.5) and -1.5 to -0.1 per thousand delta/sup 13/C (average -0.4). REE patterns for zoned dolospar have positive Ce anomalies, but total REE abundance is similar to REE abundance for replacive dolomites. Stratigraphic occurrence in an open marine setting, stable isotopes, and REE patterns suggest replacive dolomite phases formed during shallow burial diagenesis with significant involvement of nonevaporated sea water. More negative Ce anomalies near the top of the biostrome suggest a diagenetic overprint by oxidizing meteoric waters. Zoned dolospar probably formed from warmer, reducing burial fluids. Carbon for zoned dolospar probably was recycled from preexisting dolomite. These data may be useful for interpreting the origin of other anomalous platform dolostones.

Effects of watershed and in-stream liming on macroinvertebrate communities in acidified tributaries to an Adirondack lake

Science.gov (United States)

George, Scott D.; Baldigo, Barry P.; Lawrence, Gregory B.; Fuller, Randall L.

2018-01-01

Liming techniques are being explored as a means to accelerate the recovery of aquatic biota from decades of acid deposition in many regions. The preservation or restoration of native sportfish populations has typically been the impetus for liming programs, and as such, less attention has been given to its effects on other biological assemblages such as macroinvertebrates. Furthermore, the differing effects of various lime application strategies such as in-stream and watershed applications are not well understood. In 2012, a program was initiated using in-stream and aerial (whole-watershed) liming to improve water quality and Brook Trout (Salvelinus fontinalis) recruitment in three acidified tributaries of a high-elevation Adirondack lake in New York State. Concurrently, macroinvertebrates were sampled annually between 2013 and 2016 at 3 treated sites and 3 untreated reference sites to assess the effects of each liming technique on this community. Despite improvements in water chemistry in all three limed streams, our results generally suggest that neither liming technique succeeded in improving the condition of macroinvertebrate communities. The watershed application caused an immediate and unsustained decrease in the density of macroinvertebrates and increase in the proportion of sensitive taxa. These changes were driven primarily by a one-year 71 percent reduction of the acid-tolerant Leuctra stoneflies and likely represent an initial chemistry shock from the lime application rather than a recovery response. The in-stream applications appeared to reduce the density of macroinvertebrates, particularly in one stream where undissolved lime covered the natural substrate. The close proximity of our study sites to the in-stream application points (50 and 1230 m) may partly explain these negative effects. Our results are consistent with prior studies of in-stream liming which indicate that this technique often fails to restore macroinvertebrate communities to a pre

The effects of dolomitization on petrophysical properties and fracture distribution within rift-related carbonates (Hammam Faraun Fault Block, Suez Rift, Egypt)

Science.gov (United States)

Korneva, I.; Bastesen, E.; Corlett, H.; Eker, A.; Hirani, J.; Hollis, C.; Gawthorpe, R. L.; Rotevatn, A.; Taylor, R.

2018-03-01

Petrographic and petrophysical data from different limestone lithofacies (skeletal packstones, matrix-supported conglomerates and foraminiferal grainstones) and their dolomitized equivalents within a slope carbonate succession (Eocene Thebes Formation) of Hammam Faraun Fault Block (Suez Rift, Egypt) have been analyzed in order to link fracture distribution with mechanical and textural properties of these rocks. Two phases of dolomitization resulted in facies-selective stratabound dolostones extending up to two and a half kilometers from the Hammam Faraun Fault, and massive dolostones in the vicinity of the fault (100 metres). Stratabound dolostones are characterized by up to 8 times lower porosity and 6 times higher frequency of fractures compared to the host limestones. Precursor lithofacies type has no significant effect on fracture frequency in the stratabound dolostones. At a distance of 100 metres from the fault, massive dolostones are present which have 0.5 times porosity of precursor limestones, and lithofacies type exerts a stronger control on fracture frequency than the presence of dolomitization (undolomitized vs. dolomitized). Massive dolomitization corresponds to increased fracture intensity in conglomerates and grainstones but decreased fracture intensity in packstones. This corresponds to a decrease of grain/crystal size in conglomerates and grainstones and its increase in packstones after massive dolomitization. Since fractures may contribute significantly to the flow properties of a carbonate rock, the work presented herein has significant applicability to hydrocarbon exploration and production from limestone and dolostone reservoirs, particularly where matrix porosities are low.

Radiation dose estimation from the radioactivity analysis of lime and cement used in Bangladesh

International Nuclear Information System (INIS)

Alam, M.N.; Miah, M.M.H.; Chowdhury, M.I.; Kamal, M.; Ghose, S.; Islam, M.N.; Mustafa, M.N.; Miah, M.S.R.

1999-01-01

The radioactivity concentrations of 232 Th, 226 Ra, 40 K and 137 Cs were measured using high-resolution γ-ray spectrometry in limestone, powdered lime, by-product lime and cement used in Bangladesh. The activity concentrations, Ra equivalent activities, representative level index values for all samples and the effective dose equivalents due to the intake of the above-mentioned radionuclides in limestone and powdered lime by the adult group were estimated. The mean activity concentrations of 232 Th, 226 Ra and 40 K were 60.8, 60.2 and 928 Bq kg -1 , respectively for limestone, 107, 68.0 and 1660 Bq kg -1 , respectively, for powdered lime and 83.0, 31.0 and 972 Bq kg -1 , respectively, for by-product lime. For cement, the mean activity concentrations of 232 Th, 226 Ra and 40 K were observed to be 54.3, 29.7 and 523 Bq kg -1 , respectively. The presence of 137 Cs was not detectable in any of the studied samples. The measured average activities of 232 Th, 226 Ra and 40 K for all samples were relatively higher than the world typical values except for 226 Ra in cement and by-product lime. The calculated mean Ra equivalent values for limestone, powdered lime, by-product lime and cement were 219, 349, 224 and 148 Bq kg -1 , respectively. The corresponding representative level index values were found to be 1.63, 2.63, 1.68 and 1.09, respectively. The mean effective dose equivalent values of 232 Th, 226 Ra and 40 K for limestone were 56.5x10 -7 , 41.6x10 -8 and 50.8x10 -10 Sv g -1 , respectively, and those for powdered lime were 99.5x10 -7 , 46.9x10 -8 and 91.3x10 -10 Sv g -1 , respectively. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

[Skin hydration and hydrating products].

Science.gov (United States)

Duplan, H; Nocera, T

2018-05-01

One of the skin's principal functions is to protect the body against its environment by maintaining an effective epidermal barrier, not only against external factors, but also to prevent water loss from the body. Indeed, water homeostasis is vital for the normal physiological functioning of skin. Hydration levels affect not only visible microscopic parameters such as the suppleness and softness of skin, but also molecular parameters, enzyme activities and cellular signalling within the epidermis. The body is continually losing some of its water, but this phenomenon is limited and the optimal hydration gradient in skin is ensured via a set of sophisticated regulatory processes that rely on the functional and dynamic properties of the uppermost level of the skin consisting of the stratum corneum. The present article brings together data recently acquired in the fields of skin hydration and the characterisation of dehydrated or dry skin, whether through study of the regulatory processes involved or as a result of changes in the techniques used for in situ measurement, and thus in optimisation of management. Copyright © 2018. Published by Elsevier Masson SAS.

Hydration Properties of Ground Granulated Blast-Furnace Slag (GGBS Under Different Hydration Environments

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Shuhua LIU

2017-02-01

Full Text Available The hydration properties of various cementitious materials containing Ground Granulated Blast-furnace Slag (GGBS, two alkali-activated slag cements (AAS-1 and AAS-2 in which sodium silicate and sodium hydroxide act as alkaline activators respectively, supersulfated cement (SSC and slag Portland cement(PSC, are compared with ordinary Portland cement (OPC to investigate the effect of activating environment on the hydration properties in this study by determining the compressive strength of the pastes, the hydration heat of binders within 96 hours, and the hydration products at age of 28 days. The results show that C-S-H gels are the main hydrated products for all cementitious systems containing GGBS. Ca(OH2 is the hydration products of OPC and PSC paste. However, ettringite and gypsum crystals instead of Ca(OH2 are detected in SSC paste. Additionally, tobermorite, a crystalline C-S-H, and calcite are hydrated products in AAS-1. Tobermorite, cowlesite and calcite are hydrated products of AAS-2 as well. Based on strength results, AAS-1 paste exhibits the highest compressive strength followed by POC, PSC, SSC in order at all testing ages and AAS-2 give the lowest compressive strength except for the early age at 3 days, which is higher than SSC but still lower than PSC. From hydration heat analysis, alkalinity in the reaction solution is a vital factor influencing the initial hydration rate and the initial hydration rate from higher to lower is AAS-2, AAS-1, OPC, PSC and SSC. Although AAS possesses a faster reaction rate in the initial hours, cumulative hydration heat of AAS is comparably lower than that of OPC, but higher than those of PSC and SSC in turn, which indicates that the hydration heat of clinkers is much higher than that of slag.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.14934

Effects of the dolomite from Irati formation as additive in a refractory clay used as raw material in Santa Gertrudes ceramic cluster (SP)

International Nuclear Information System (INIS)

Souza, M.H.O.; Gaspar Junior, L.A.; Moreno, M.M.T.

2011-01-01

The effects of addition of carbonates in clays used as floor tiles have been intensively studied, but the focus usually is the pure calcite or calcitic limestone, which has nobler uses in industry, especially for cement production. However, in the important area known as Santa Gertrudes Ceramic Cluster, in Sao Paulo State, occurs mainly the dolomitic limestone, which is little studied as a potential additive which could be used in order to improve the properties of the floor tiles. This work aimed to check out the potentiality of dolomitic limestone as additive in ceramic products, especially floor tiles. Using as ingredients dolomitic limestones and refractory clay collected inside the area of the referred cluster, ceramic bodies were obtained with different dolomitic limestones contents incorporated to the refractory clay, and these ceramic bodies were mineralogically, chemically and physically analyzed. The conclusions are the dolomitic limestone can be particularly useful when incorporated to refractory clays, due to its fluxing properties. (author)

Effect of liquid liming on sorghum growth in an Ultisol.

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Manuel E. Camacho

2015-06-01

Full Text Available   The aim of this study was to evaluate the effects of the application of liquid lime on sorghum growth in an Ultisol. This research was conducted between August and November, 2011 at the Agricultural Research Center, San José, Costa Rica. In an Ultisol planted with sorghum, in pots of 800 ml, the following treatments where applied: control without lime, calcium carbonate at doses of 10 and 20 l/ha, magnesium oxide at doses of 10 and 20 l/ha, calcium carbonate + magnesium oxide at doses of 5 + 5 and 10 + 10 l/ha, respectively. Six weeks after planting, sorghum was harvested, measuring leaf area, dry and fresh weight of the aerial and root biomass, nutrient absorption and the soil chemical characteristics. Treatments using calcium carbonate and calcium carbonate + magnesium oxide obtained the best values of leaf area and the higher weight of the aerial and root biomass of sorghum. Even though there were no significant differences between liquid lime treatments, there were regarding control without lime and weight biomass variables. Liquid calcium carbonate significantly increased Ca absorption, and the calcium carbonate + magnesium oxide treatment at doses of 10 l/h showed the highest Mg absorption. All amendment treatments caused an improvement of the soil fertility, the most notable being the application of 20 l/ha of magnesium oxide that dropped the exchangeable acidity from 9.02 to 0.36 cmol(+/l, acidity saturation dropped from 95 to 3.3%, and pH increased from 5 to 5.7. It was concluded that the liquid liming amendments had a positive effect over the crop and the soil fertility.

The relationships among lemons, limes and citron: a chromosomal comparison.

Science.gov (United States)

Carvalho, R; Soares Filho, W S; Brasileiro-Vidal, A C; Guerra, M

2005-01-01

Lemons, limes and citron constitute a group of closely related Citrus species, whose species delimitations and taxonomic relationships are unclear. In order to identify karyotypic similarities and species relationships within this group, the CMA+/DAPI- banding pattern and the distribution of the 5S and 45S rDNA sites of 10 accessions of lime, lemon, and citron were investigated. The four cultivars of C. limon analyzed showed the same pattern of CMA+ bands and rDNA sites, suggesting that they originated from a single germplasm, later differentiated by distinct somatic mutations. The lemons C. jambhiri, C. limonia and C. volkameriana displayed karyotypes very similar to each other, but they differed from C. limon by the absence of a single chromosome with one band in each telomere. The limes, C. aurantifolia and C. limettioides, seemed less related to each other and exhibited different heteromorphic chromosome pairs. In C. aurantifolia, the presence of a chromosome type unknown in all other Citrus species cytologically known so far supports the assumption that this accession may be derived from a hybrid with a species from the subgenus Papeda or from another genus. Citrus medica was the only homozygous accession of this group and all of its chromosome types were clearly represented in limes and lemons, some of them forming heteromorphic pairs. The analysis of the distribution of rDNA sites allowed a further refinement of the comparison among accessions. The lemons and limes were heterozygous for all rDNA sites, whereas C. medica was entirely homozygous. These data support the hypothesis that C. medica is a true species while the other nine accessions are hybrids. Copyright 2005 S. Karger AG, Basel.

Application and properties of pure lime façades - case study

Directory of Open Access Journals (Sweden)

Violeta Bokan Bosiljkov

2008-01-01

Full Text Available The paper presents experiences obtained during application and testing of different pure lime façades that could be successfully used in restoration of historical buildings in Slovenia. The lime façade consists of a rendering layer (rough mortar, a finishing layer (fine mortar and a protective layer of lime wash. For the design of the mortars different industrially and traditionally produced limes were chosen, based on the results of preliminary studies of the authors and experiences of a small enterprise (SE involved in the study. The façade layers were applied to the most problematic northern wall of the historic chapel made from rubble masonry. The chapel belongs to the castle Crnelo, built at the end of the 17th century in the village Turnše, not far from Ljubljana, the capital of Slovenia. The façade layers were made by skilled workers of SE, with about one year time difference between application of rendering and finishing layers, and with a protective layer of coloured lime wash applied to one to three day old finishing layers. On the rendering layers, visual inspection, water absorption tests and determination of carbonation depth were carried out before subsequent finishing layers were applied. The same on-site tests were carried out also on finished façade layers. So far, parallel to the on-site tests, compressive and water absorption tests on prisms prepared from rough mortars were carried out in laboratory.

Effect of liming on the behaviour of 90Sr and 137Cs in a lake ecosystem

International Nuclear Information System (INIS)

Outola, Iisa; Rask, Martti

2011-01-01

Liming of lakes is considered one possible remedial action to reduce the accumulation of radionuclides into fish in the case of a radiological accident. These responses were tested in field conditions in a small acidified lake that was divided into two parts: one limed with CaCO 3 and the other half left as an unlimed control. The transfer of 90 Sr from water into fish decreased on average by 50% during the first year after liming. However, at the same time the 90 Sr concentration in water increased, reaching a maximum within 6 months after liming. Approximately 50% more 90 Sr was detected in water in the limed part of the lake than on control side during the first year. 90 Sr was most probably released from the sediment as the Ca concentration and pH of the water increased. As a result of these two processes, which counterbalanced each other (increased release of 90 Sr into water from sediment and decreased transfer of 90 Sr from water into fish), the 90 Sr concentration in fish did not notably differ between the limed and control sides of the lake. Liming may only be suitable as a remedial action if carried out immediately after a radiological accident, before significant amounts of radionuclides have been deposited in lake sediments. In the case of 137 Cs, the effect of liming was less pronounced. 137 Cs activity concentration in water increased in the first year by 20% and uptake by fish decreased by 20%. - Highlights: → Acidified lake was divided into two parts: one limed with CaCO 3 and the other half left as an unlimed control. → The transfer of 90 Sr from water into fish decreased by 50% during the first year after liming. → At the same time liming increased the 90 Sr concentration in the water by 50%. → The increased amount of 90 Sr in water is assumed to have originated from the lake sediments. → The 90 Sr concentration in fish remained relatively unchanged.

Genetic variation assessment of acid lime accessions collected from south of Iran using SSR and ISSR molecular markers.

Science.gov (United States)

Sharafi, Ata Allah; Abkenar, Asad Asadi; Sharafi, Ali; Masaeli, Mohammad

2016-01-01

Iran has a long history of acid lime cultivation and propagation. In this study, genetic variation in 28 acid lime accessions from five regions of south of Iran, and their relatedness with other 19 citrus cultivars were analyzed using Simple Sequence Repeat (SSR) and Inter-Simple Sequence Repeat (ISSR) molecular markers. Nine primers for SSR and nine ISSR primers were used for allele scoring. In total, 49 SSR and 131 ISSR polymorphic alleles were detected. Cluster analysis of SSR and ISSR data showed that most of the acid lime accessions (19 genotypes) have hybrid origin and genetically distance with nucellar of Mexican lime (9 genotypes). As nucellar of Mexican lime are susceptible to phytoplasma, these acid lime genotypes can be used to evaluate their tolerance against biotic constricts like lime "witches' broom disease".

The Effect of Kaffir Lime Leaves Distillation Residue Oleoresin Concentration on Active Paper Packaging Characteristics

Science.gov (United States)

Kawiji; Utami, R.; Ulum, S.; Khasanah, L. U.; Manuhara, G. J.; Atmaka, W.

2018-03-01

Oleoresin of kaffir lime leaves distillation residue still contains some active compounds such as Citronellal, β-Citronellol, and Linalool which potential to incorporated on the active paper packaging. The purposes of this study were to determine the effect of kaffir lime leaves distillation residue oleoresin concentration on the physical characteristics, sensory characteristics, and antimicrobial activity of the active paper packaging incorporated with kaffir lime leaves distillation residue oleoresin and to determine the functional groups of active paper packaging. The concentration of kaffir lime leaves distillation residue oleoresin were varied at 0%, 2%, 4% and 6%. The result showed that the addition of kaffir lime leaves distillation residue oleoresin increased the thickness and moisture content of the paper and decreased the tensile strengths and folding endurances of active paper packaging. The microbial inhibition tends to increase along with the higher oleoresin concentration addition. Aromatic CH group were found at a wavelength of 897.90 cm-1 of on paper packaging with 2% oleoresin indicated as functional aromatic functional group allegedly obtained from the kaffir lime leaves oleoresin.

Hydration water and microstructure in calcium silicate and aluminate hydrates

International Nuclear Information System (INIS)

Fratini, Emiliano; Ridi, Francesca; Chen, Sow-Hsin; Baglioni, Piero

2006-01-01

Understanding the state of the hydration water and the microstructure development in a cement paste is likely to be the key for the improvement of its ultimate strength and durability. In order to distinguish and characterize the reacted and unreacted water, the single-particle dynamics of water molecules in hydrated calcium silicates (C 3 S, C 2 S) and aluminates (C 3 A, C 4 AF) were studied by quasi-elastic neutron scattering, QENS. The time evolution of the immobile fraction represents the hydration kinetics and the mobile fraction follows a non-Debye relaxation. Less sophisticated, but more accessible and cheaper techniques, like differential scanning calorimetry, DSC, and near-infrared spectroscopy, NIR, were validated through QENS results and they allow one to easily and quantitatively follow the cement hydration kinetics and can be widely applied on a laboratory scale to understand the effect of additives (i.e., superplasticizers, cellulosic derivatives, etc) on the thermodynamics of the hydration process. DSC provides information on the free water index and on the activation energy involved in the hydration process while the NIR band at 7000 cm -1 monitors, at a molecular level, the increase of the surface-interacting water. We report as an example the effect of two classes of additives widely used in the cement industry: superplasticizers, SPs, and cellulose derivatives. SPs interact at the solid surface, leading to a consistent increment of the activation energy for the processes of nucleation and growth of the hydrated phases. In contrast, the cellulosic additives do not affect the nucleation and growth activation energy, but cause a significant increment in the water availability: in other words the hydration process is more efficient without any modification of the solid/liquid interaction, as also evidenced by the 1 H-NMR. Additional information is obtained by scanning electron microscopy (SEM), ultra small angle neutron scattering (USANS) and wide

Novel understanding of calcium silicate hydrate from dilute hydration

KAUST Repository

Zhang, Lina; Yamauchi, Kazuo; Li, Zongjin; Zhang, Xixiang; Ma, Hongyan; Ge, Shenguang

2017-01-01

The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10

Historical methane hydrate project review

Science.gov (United States)

Collett, Timothy; Bahk, Jang-Jun; Frye, Matt; Goldberg, Dave; Husebo, Jarle; Koh, Carolyn; Malone, Mitch; Shipp, Craig; Torres, Marta

2013-01-01

In 1995, U.S. Geological Survey made the first systematic assessment of the volume of natural gas stored in the hydrate accumulations of the United States. That study, along with numerous other studies, has shown that the amount of gas stored as methane hydrates in the world greatly exceeds the volume of known conventional gas resources. However, gas hydrates represent both a scientific and technical challenge and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of gas hydrates in nature, (2) assessing the volume of natural gas stored within various gas hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural gas hydrates, and (5) analyzing the effects of methane hydrate on drilling safety.Methane hydrates are naturally occurring crystalline substances composed of water and gas, in which a solid water-­‐lattice holds gas molecules in a cage-­‐like structure. The gas and water becomes a solid under specific temperature and pressure conditions within the Earth, called the hydrate stability zone. Other factors that control the presence of methane hydrate in nature include the source of the gas included within the hydrates, the physical and chemical controls on the migration of gas with a sedimentary basin containing methane hydrates, the availability of the water also included in the hydrate structure, and the presence of a suitable host sediment or “reservoir”. The geologic controls on the occurrence of gas hydrates have become collectively known as the “methane hydrate petroleum system”, which has become the focus of numerous hydrate research programs.Recognizing the importance of methane hydrate research and the need for a coordinated

Expansive soil stabilization with coir waste and lime for flexible pavement subgrade

Science.gov (United States)

Narendra Goud, G.; Hyma, A.; Shiva Chandra, V.; Sandhya Rani, R.

2018-03-01

Expansive soil properties can be improved by various methods to make it suitable for construction of flexible pavement. The coir pith is the by-product (bio-waste) generated from coir industry during extraction of coir fiber from coconut husk. Openly disposed coir pith can make the surrounding areas unhygienic. This bio-waste can be one of the potential materials to stabilize the expansive soils. In the present study coir pith and lime are used as stabilizers. Different combinations of coir pith contents (1%, 2% and 3%) and lime contents (2%, 3% and 4%)are used to study the behavior of expansive soil. Unconfined compressive strength (UCS) of unstabilized and stabilized soils was determined. Optimum content of coir pith and lime are determined based on UCS of the soil. California bearing ratio of soil determined at optimum contents of coir pith and lime. Flexible pavement layer compositions for two levels of traffic using stabilized soil subgrade.

Lime kiln dust as a potential raw material in portland cement manufacturing

Science.gov (United States)

Miller, M. Michael; Callaghan, Robert M.

2004-01-01

In the United States, the manufacture of portland cement involves burning in a rotary kiln a finely ground proportional mix of raw materials. The raw material mix provides the required chemical combination of calcium, silicon, aluminum, iron, and small amounts of other ingredients. The majority of calcium is supplied in the form of calcium carbonate usually from limestone. Other sources including waste materials or byproducts from other industries can be used to supply calcium (or lime, CaO), provided they have sufficiently high CaO content, have low magnesia content (less than 5 percent), and are competitive with limestone in terms of cost and adequacy of supply. In the United States, the lime industry produces large amounts of lime kiln dust (LKD), which is collected by dust control systems. This LKD may be a supplemental source of calcium for cement plants, if the lime and cement plants are located near enough to each other to make the arrangement economical.

Nutritional value of organic acid lime juice (Citrus latifolia T., cv. Tahiti

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Carolina Netto Rangel

2011-12-01

Full Text Available Acid lime can be used as fresh fruit or as juice to increase the flavor of drinks. Therefore, it is necessary to analyze organic acid lime nutritional composition in order to evaluate if there are important differences among those conventionally produced. No significant differences in total titrable acidity, pH, ascorbic acid, sucrose, calcium, and zinc were found between the acid lime juice from organic biodynamic crops and conventional crops. However, the organic biodynamic fruits presented higher peel percentage than the conventional ones leading to lower juice yield. On the other hand, fructose, glucose, total soluble solids contents, potassium, manganese, iron, and copper were higher in the conventional samples. These results indicated few nutritional differences between organic and conventional acid lime juices in some constituents. Nevertheless, fruit juice from biodynamic crops could be a good choice since it is free from pesticides and other agents that cause problems to human health maintaining the levels similar to those of important nutritional compounds.

Dissolved organic carbon and nitrogen mineralization strongly affect co2 emissions following lime application to acidic soil

International Nuclear Information System (INIS)

Shaaban, M.; Peng, Q.; Lin, S.; Wu, Y.

2014-01-01

Emission of greenhouse gases from agricultural soils has main contribution to the climatic change and global warming. Dynamics of dissolved organic carbon (DOC) and nitrogen mineralization can affect CO/sub 2/ emission from soils. Influence of DOC and nitrogen mineralization on CO/sub 2/ emissions following lime application to acidic soil was investigated in current study. Laboratory experiment was conducted under aerobic conditions with 25% moisture contents (66% water-filled pore space) at 25 degree C in the dark conditions. Different treatments of lime were applied to acidic soil as follows: CK (control), L (low rate of lime: 0.2g lime / 100 g soil) and H (high rate of lime: 0.5g lime /100g soil). CO/sub 2/ emissions were measured by gas chromatography and dissolved organic carbon, NH4 +-N, NO/sub 3/ --N and soil pH were measured during incubation study. Addition of lime to acidic soil significantly increased the concentration of DOC and N mineralization rate. Higher concentrations of DOC and N mineralization, consequently, increased the CO/sub 2/ emissions from lime treated soils. Cumulative CO/sub 2/ emission was 75% and 71% higher from L and H treatments as compared to CK. The results of current study suggest that DOC and N mineralization are critical in controlling gaseous emissions of CO/sub 2/ from acidic soils following lime application. (author)

Removal of Phosphate from Synthetic Aqueous Solution by Adsorption with Dolomite from Padalarang

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Fadjari Lucia Nugroho

2014-12-01

Full Text Available The presence of phosphate in wastewaters can cause eutrophication of surface water bodies leading to algal-blooming in the aquatic environment and degradation of water quality. Phosphate removal from wastewaters by conventional biological treatment removes only 10-30% of the phosphate, whilst chemical treatment using precipitants such as calcium or iron salts, although effective, is expensive and produces water-rich sludge which must be further treated. Hence, phosphate removal by adsorption in the form of Ca -phosphate has been proposed as an alternative to the more traditional methods. This study investigated the feasibility of using dolomite–a common sedimentary rock–from Padalarang, West Java, Indonesia as the adsorbent for the removal of phosphate from synthetic aqueous solution. Chemical analysis revealed that the Padalarang dolomite contains 33.6-36.2% CaO. Batch experiments at room temperature indicated that optimum removal of phosphate was achieved at pH 9. At 25°C , where increasing concentrations of phosphate (10–100 mg/L increased phosphate adsorption (2.15-31.3 mg/g by the dolomite. The adsorption of phosphate could be described by the Langmuir isotherm model, with constants Qm= 476.19 mg/g, K L= 0,00106 L/mg and equilibrium parameter (R L: 0.904 – 0.989. Phosphate adsorption by dolomite not only permits its removal but also its potential recovery for reuse.

Cytotoxic and antibacterial activity of the mixture of olive oil and lime cream in vitro conditions.

Science.gov (United States)

Sumer, Zeynep; Yildirim, Gulay; Sumer, Haldun; Yildirim, Sahin

2013-01-01

The mixture of olive oil and lime cream has been traditionally used to treat external burns in the region of Hatay/Antakya and middle Anatolia. Olive oil and lime cream have been employed by many physicians to treat many ailments in the past. A limited number of studies have shown the antibacterial effect of olive oil and that it does not have any toxic effect on the skin. But we did not find any reported studies on the mixture of olive oil and lime cream. The aim of this paper is to investigate the cytotoxic and antibacterial activity of olive oil and lime cream individually or/and in combination in vitro conditions, by using disk-diffusion method and in cell culture. The main purpose in using this mixture is usually to clear burns without a trace. Agar overlay, MTT (Cytotoxicity assay) and antibacterial susceptibility tests were used to investigate the cytotoxic and antibacterial activity of olive oil and lime cream. We found that lime cream has an antibacterial activity but also cytotoxic on the fibroblasts. On the other hand olive oil has limited or no antibacterial effect and it has little or no cytotoxic on the fibroblasts. When we combined lime cream and olive oil, olive oil reduced its cytotoxic impact. These results suggest that mixture of olive oil and lime cream is not cytotoxic and has antimicrobial activity.

Hydraulic and Mechanical Effects from Gas Hydrate Conversion and Secondary Gas Hydrate Formation during Injection of CO2 into CH4-Hydrate-Bearing Sediments

Science.gov (United States)

Bigalke, N.; Deusner, C.; Kossel, E.; Schicks, J. M.; Spangenberg, E.; Priegnitz, M.; Heeschen, K. U.; Abendroth, S.; Thaler, J.; Haeckel, M.

2014-12-01

The injection of CO2 into CH4-hydrate-bearing sediments has the potential to drive natural gas production and simultaneously sequester CO2 by hydrate conversion. The process aims at maintaining the in situ hydrate saturation and structure and causing limited impact on soil hydraulic properties and geomechanical stability. However, to increase hydrate conversion yields and rates it must potentially be assisted by thermal stimulation or depressurization. Further, secondary formation of CO2-rich hydrates from pore water and injected CO2 enhances hydrate conversion and CH4 production yields [1]. Technical stimulation and secondary hydrate formation add significant complexity to the bulk conversion process resulting in spatial and temporal effects on hydraulic and geomechanical properties that cannot be predicted by current reservoir simulation codes. In a combined experimental and numerical approach, it is our objective to elucidate both hydraulic and mechanical effects of CO2 injection and CH4-CO2-hydrate conversion in CH4-hydrate bearing soils. For the experimental approach we used various high-pressure flow-through systems equipped with different online and in situ monitoring tools (e.g. Raman microscopy, MRI and ERT). One particular focus was the design of triaxial cell experimental systems, which enable us to study sample behavior even during large deformations and particle flow. We present results from various flow-through high-pressure experimental studies on different scales, which indicate that hydraulic and geomechanical properties of hydrate-bearing sediments are drastically altered during and after injection of CO2. We discuss the results in light of the competing processes of hydrate dissociation, hydrate conversion and secondary hydrate formation. Our results will also contribute to the understanding of effects of temperature and pressure changes leading to dissociation of gas hydrates in ocean and permafrost systems. [1] Deusner C, Bigalke N, Kossel E

Thermal and catalytic cracking of ethylene in presence of CaO, MgO, zeolite and calcined dolomite

Energy Technology Data Exchange (ETDEWEB)

Taralas, G; Sjoestroem, K; Jaeraas, S; Bjoernbom, E [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Technology

1994-12-31

The subject of the present work is to study the effect of catalysts such as calcined dolomite (CaO.MgO), CaO (quicklime), MgO and Zeolite (EKZ-4) on the cracking of ethylene in the presence and absence of steam. N-heptane, toluene, naphthalene, thiophene have been some suitable model compounds for studies of the thermal and catalytic decomposition of tar. Previous results showed that the reaction scheme of the thermal decomposition of n-heptane was consistent with the high yield of ethylene observed in thermal decomposition of n-heptane. The effect of the reactor wall and the ferric impurities in the dolomite are also subjects of the research in this study. The results may also throw some additional light on the nature of the gas-phase thermal and catalytic reactions occurring in the use of dolomite as tar cracking catalysts. 28 refs

Strength Estimation for Hydrate-Bearing Sediments From Direct Shear Tests of Hydrate-Bearing Sand and Silt

Science.gov (United States)

Liu, Zhichao; Dai, Sheng; Ning, Fulong; Peng, Li; Wei, Houzhen; Wei, Changfu

2018-01-01

Safe and economic methane gas production, as well as the replacement of methane while sequestering carbon in natural hydrate deposits, requires enhanced geomechanical understanding of the strength and volume responses of hydrate-bearing sediments during shear. This study employs a custom-made apparatus to investigate the mechanical and volumetric behaviors of carbon dioxide hydrate-bearing sediments subjected to direct shear. The results show that both peak and residual strengths increase with increased hydrate saturation and vertical stress. Hydrate contributes mainly the cohesion and dilatancy constraint to the peak strength of hydrate-bearing sediments. The postpeak strength reduction is more evident and brittle in specimens with higher hydrate saturation and under lower stress. Significant strength reduction after shear failure is expected in silty sediments with high hydrate saturation Sh ≥ 0.65. Hydrate contribution to the residual strength is mainly by increasing cohesion at low hydrate saturation and friction at high hydrate saturation. Stress state and hydrate saturation are dominating both the stiffness and the strength of hydrate-bearing sediments; thus, a wave velocity-based peak strength prediction model is proposed and validated, which allows for precise estimation of the shear strength of hydrate-bearing sediments through acoustic logging data. This method is advantageous to geomechanical simulators, particularly when the experimental strength data of natural samples are not available.

Gas hydrate concentration and characteristics within Hydrate Ridge inferred from multicomponent seismic reflection data

Science.gov (United States)

Kumar, Dhananjay; Sen, Mrinal K.; Bangs, Nathan L.

2007-12-01

A seismic experiment composed of streamer and ocean bottom seismometer (OBS) surveys was conducted in the summer of 2002 at southern Hydrate Ridge, offshore Oregon, to map the gas hydrate distribution within the hydrate stability zone. Gas hydrate concentrations within the reservoir can be estimated with P wave velocity (Vp); however, we can further constrain gas hydrate concentrations using S wave velocity (Vs), and use Vs through its relationship to Vp (Vp/Vs) to reveal additional details such as gas hydrate form within the matrix (i.e., hydrate cements the grains, becomes part of the matrix frame or floats in pore space). Both Vp and Vs can be derived simultaneously by inverting multicomponent seismic data. In this study, we use OBS data to estimate seismic velocities where both gas hydrate and free gas are present in the shallow sediments. Once Vp and Vs are estimated, they are simultaneously matched with modeled velocities to estimate the gas hydrate concentration. We model Vp using an equation based on a modification of Wood's equation that incorporates an appropriate rock physics model and Vs using an empirical relation. The gas hydrate concentration is estimated to be up to 7% of the rock volume, or 12% of the pore space. However, Vp and Vs do not always fit the model simultaneously. Vp can vary substantially more than Vs. Thus we conclude that a model, in which higher concentrations of hydrate do not affect shear stiffness, is more appropriate. Results suggest gas hydrates form within the pore space of the sediments and become part of the rock framework in our survey area.

Application of lime and urea and its effect on development of Phythophthora palmivora.

Directory of Open Access Journals (Sweden)

Sakti Widyanta Pratama

2015-03-01

Full Text Available Black pod rot disease (BPRD which is caused by Phytophthora palmivora is one of the main diseases of cocoa cultivations particularly in plantations with wet climate. Black pod rot can develop rapidly under high humidity environments, particularly during rainy seasons. This disease can cause loss of harvest of up to 46.63% in East Java. The various control efforts attempted so far have not resulted in significant improvements. Urea, in addition to functioning as fertilizer, can also produce the ammonia gas which is believed to be able to suppress black pod rot. This research aims to determine the effectiveness of black pod rot control using the combination of lime and urea. This research was conducted from June to September 2013. The materials used in test included sterile soil, black pod rot infected cocoa, urea, and agricultural lime. Observation results showed that ammonia could form from urea. Lime can increase the speed of the formation. The ammonia gas forming from 0.06% urea and 0.3% lime can control the P. palmivora fungus inside the soil. Key words: Pod rot, P. palmivora, urea, lime, ammonia

MANAGEMENT OF ROOT ROT IN AVOCADO TREES

Directory of Open Access Journals (Sweden)

SIMONE RODRIGUES DA SILVA

Full Text Available ABSTRACT Root rot (Phytophthora cinnamomi Rands is one of the most restrictive factors to avocado growing in main producing regions worldwide. In Brazil, scientific reports on the effectiveness of control methods are scarce. The objective of this study was to evaluate the efficiency of gypsum applications and dolomitic limestone to the soil and potassium phosphite sprays in controlling this disease in ‘Hass’ avocado, grown without irrigation. The application of dolomitic limestone or gypsum alone is not effective to recover plants affected by root rot. The application of potassium phosphite, combined or not with dolomitic lime or gypsum enables the partial recovery ‘Hass’ avocado plants affected by the disease.

Ferroan dolomite cement in Cambrian sandstones: burial history and hydrocarbon generation of the Baltic sedimentary basin

DEFF Research Database (Denmark)

Sliaupa, S.; Cyziene, J.; Molenaar, Nicolaas

2008-01-01

The conditions and timing of carbonate cementation in Cambrian sandstones of the Baltic sedimentary basin were determined by oxygen and carbon stable isotope and chemical data in combination with optical and cathodoluminescence petrographic studies. Studied samples represent a range in present...... burial depth from 340 to 2150 m. The carbonate cement is dominantly ferroan dolomite that occurs as dispersed patches of poikilotopic crystals. Temperatures of dolomite precipitation, based on delta O-18 values, range from 27 degrees C in the shallow buried to 95 degrees C in the deep buried sandstones...

A systematic review of the effectiveness of liming to mitigate impacts of river acidification on fish and macro-invertebrates

International Nuclear Information System (INIS)

Mant, Rebecca C.; Jones, David L.; Reynolds, Brian; Ormerod, Steve J.; Pullin, Andrew S.

2013-01-01

The addition of calcium carbonate to catchments or watercourses – liming – has been used widely to mitigate freshwater acidification but the abatement of acidifying emissions has led to questions about its effectiveness and necessity. We conducted a systematic review and meta-analysis of the impact of liming streams and rivers on two key groups of river organisms: fish and invertebrates. On average, liming increased the abundance and richness of acid-sensitive invertebrates and increased overall fish abundance, but benefits were variable and not guaranteed in all rivers. Where B-A-C-I designs (before-after-control-impact) were used to reduce bias, there was evidence that liming decreased overall invertebrate abundance. This systematic review indicates that liming has the potential to mitigate the symptoms of acidification in some instances, but effects are mixed. Future studies should use robust designs to isolate recovery due to liming from decreasing acid deposition, and assess factors affecting liming outcomes. -- Highlights: •In a systematic review and meta-analysis, we asked how river liming affected fish and invertebrates. •On average, liming increased fish abundance. •Liming also increased average abundance and richness of acid-sensitive invertebrates. •However, benefits were variable and not guaranteed in all acidified rivers. -- A systematic review showed lime application to acidified rivers increased average fish abundance, and abundance and richness in acid-sensitive invertebrates, but not always

Influence of lime on struvite formation and nitrogen conservation during food waste composting.

Science.gov (United States)

Wang, Xuan; Selvam, Ammaiyappan; Wong, Jonathan W C

2016-10-01

This study aimed at investigating the feasibility of supplementing lime with struvite salts to reduce ammonia emission and salinity consequently to accelerate the compost maturity. Composting was performed in 20-L bench-scale reactors for 35days using artificial food waste mixed with sawdust at 1.2:1 (w/w dry basis), and Mg and P salts (MgO and K2HPO4, respectively). Nitrogen loss was significantly reduced from 44.3% to 27.4% during composting through struvite formation even with the addition of lime. Lime addition significantly reduced the salinity to less than 4mS/cm with a positive effect on improving compost maturity. Thus addition of both lime and struvite salts synergistically provide advantages to buffer the pH, reduce ammonia emission and salinity, and accelerate food waste composting. Copyright © 2016 Elsevier Ltd. All rights reserved.

Establishing the Relationship between Fracture-Related Dolomite and Primary Rock Fabric on the Distribution of Reservoirs in the Michigan Basin

Energy Technology Data Exchange (ETDEWEB)

G. Michael Grammer

2006-09-30

This topical report covers the year 2 of the subject 3-year grant, evaluating the relationship between fracture-related dolomite and dolomite constrained by primary rock fabric in the 3 most prolific reservoir intervals in the Michigan Basin (Ordovician Trenton-Black River Formations; Silurian Niagara Group; and the Devonian Dundee Formation). The characterization of select dolomite reservoirs has been the major focus of our efforts in Phase II/Year 2. Fields have been prioritized based upon the availability of rock data for interpretation of depositional environments, fracture density and distribution as well as thin section, geochemical, and petrophysical analyses. Structural mapping and log analysis in the Dundee (Devonian) and Trenton/Black River (Ordovician) suggest a close spatial relationship among gross dolomite distribution and regional-scale, wrench fault related NW-SE and NE-SW structural trends. A high temperature origin for much of the dolomite in the 3 studied intervals (based upon initial fluid inclusion homogenization temperatures and stable isotopic analyses,) coupled with persistent association of this dolomite in reservoirs coincident with wrench fault-related features, is strong evidence for these reservoirs being influenced by hydrothermal dolomitization. For the Niagaran (Silurian), a comprehensive high resolution sequence stratigraphic framework has been developed for a pinnacle reef in the northern reef trend where we had 100% core coverage throughout the reef section. Major findings to date are that facies types, when analyzed at a detailed level, have direct links to reservoir porosity and permeability in these dolomites. This pattern is consistent with our original hypothesis of primary facies control on dolomitization and resulting reservoir quality at some level. The identification of distinct and predictable vertical stacking patterns within a hierarchical sequence and cycle framework provides a high degree of confidence at this point

Shear strength and compressibility behaviour of lime-treated organic clay

OpenAIRE

Yunus, NZM; Wanatowski, D; Hassan, NA; Marto, A

2016-01-01

Apart from strength characteristics, a review of studies on the compressibility of lime-treated soils is equally important that influenced the stability of soil structures. Due to the fact that no study has been carried out, an investigation on the effects of humic acid on strength and compressibility behaviour of lime-stabilised organic clay is presented in this paper. Unconfined Compressive Strength (UCS) and oedometer tests were carried out at different curing periods of 7, 28 and 90 days....

Effectiveness of lime and peat applications on cadmium availability in a paddy soil under various moisture regimes.

Science.gov (United States)

Chen, Yanhui; Xie, Tuanhui; Liang, Qiaofeng; Liu, Mengjiao; Zhao, Mingliu; Wang, Mingkuang; Wang, Guo

2016-04-01

In paddy soils, amendments and moisture play important role in the immobilization of cadmium (Cd). The effects of applying lime, peat, and a combination of both on soil Eh, pH, and Cd availability in contaminated soils were investigated under wetted (80 ± 5 % of water holding capacity) and flooded (completely submerged) conditions. In wetted soils, there was little change in Eh, compared to flooded soils where Eh reduced rapidly. Amendments of lime only or in a mixture with peat increased soil pH to different degrees, depending on the lime application rate. However, peat addition only slightly affected soil pH. The decreased Cd availability in flooded soils was related to submergence duration and was significantly lower than that in wetted soils after 14 days. Liming wetted and flooded soils decreased exchangeable Cd and increased carbonates or Fe-Mn oxides bound fractions, while peat addition transformed Cd from carbonates to organic matter bound fractions. The combined application of peat and lime generally showed better inhibitory effects on the availability of Cd than separately application of lime or peat. Higher application rates of lime, peat, or their mixture were more effective at reducing Cd contamination in flooded soil. This indicates that application of peat and lime mixture under flooded conditions was most effective for in situ remediation of Cd-contaminated soils. Further studies are required to assess the long-term effectiveness of the peat and lime mixture on Cd availability in paddy soils.

Application of empirical hydration distribution functions around polar atoms for assessing hydration structures of proteins

International Nuclear Information System (INIS)

Matsuoka, Daisuke; Nakasako, Masayoshi

2013-01-01

Highlights: ► Empirical distribution functions of water molecules in protein hydration are made. ► The functions measure how hydrogen-bond geometry in hydration deviate from ideal. ► The functions assess experimentally identified hydration structures of protein. - Abstract: To quantitatively characterize hydrogen-bond geometry in local hydration structures of proteins, we constructed a set of empirical hydration distribution functions (EHDFs) around polar protein atoms in the main and side chains of 11 types of hydrophilic amino acids (D. Matsuoka, M. Nakasako, Journal of Physical Chemistry B 113 (2009) 11274). The functions are the ensemble average of possible hydration patterns around the polar atoms, and describe the anisotropic deviations from ideal hydrogen bond geometry. In addition, we defined probability distribution function of hydration water molecules (PDFH) over the hydrophilic surface of a protein as the sum of EHDFs of solvent accessible polar protein atoms. The functions envelop most of hydration sites identified in crystal structures of proteins (D. Matsuoka, M. Nakasako, Journal of Physical Chemistry B 114 (2010) 4652). Here we propose the application of EHDFs and PDFHs for assessing crystallographically identified hydration structures of proteins. First, hydration water molecules are classified with respect to the geometry in hydrogen bonds in referring EHDFs. Difference Fourier electron density map weighted by PDFH of protein is proposed to identify easily density peaks as candidates of hydration water molecules. A computer program implementing those ideas was developed and used for assessing hydration structures of proteins

Thermophysical properties of enzyme clarified Lime (Citrus aurantifolia L) juice at different moisture contents.

Science.gov (United States)

Manjunatha, S S; Raju, P S; Bawa, A S

2014-11-01

Thermophysical properties of enzyme clarified lime (Citrus aurantifolia L.) juice were evaluated at different moisture contents ranging from 30.37 % to 89.30 % (wet basis) corresponding to a water activity range of 0.835 to 0.979. The thermophysical properties evaluated were density, Newtonian viscosity, thermal conductivity, specific heat and thermal diffusivity. The investigation showed that density and Newtonian viscosity of enzyme clarified lime juice decreased significantly (p lime juice with moisture content/water activity employing regression analysis by the method of least square approximation. Results indicated the existence of strong correlation between thermophysical properties and moisture content/water activity of enzyme clarified lime juice, a significant (p < 0.0001) negative correlation between physical and thermal properties was observed.

Influence of the mechanical properties of lime mortar on the strength of brick masonry

OpenAIRE

PAVIA, SARA

2013-01-01

PUBLISHED This paper aims at improving the quality of lime mortar masonry by understanding the mechanics of mortars and masonry and their interaction. It investigates how the mortar?s compressive and flexural strengths impact the compressive and bond strength of clay brick masonry bound with calcium lime (CL) and natural hydraulic lime (NHL) mortars. It concludes that the strength of the bond has a greater impact on the compressive strength of masonry than the mortar?s st...

A thermoluminescence study of vempalle dolomites and its depositional environments

International Nuclear Information System (INIS)

Bhattacharya, A.K.; Rao, C.N.; Kaul, I.K.

1976-01-01

An attempt has been made to interpret the depositional environment of Vempalle dolomites (India) by thermoluminescence method. It has been demonstrated that glow curve patterns reflect the environmental condition of deposition for carbonate sediments. The glow curves were obtained for natural samples as well as samples irradiated by Co 60 and compared. A majority of the samples were concluded to be diagenetic. (A.K.)

Estimation of atmospheric fluoride by limed filter papers

International Nuclear Information System (INIS)

Smith, D.R.

1988-09-01

The limed filter paper method of static sampling of atmospheric fluoride is reviewed in this report. Use of the technique, in conjunction with precise measurement of the absorbed fluoride and calibration with dynamic air sampling techniques, to estimate atmospheric fluoride levels, is considered to give only qualitative data (± 50%). The limed filter paper method is site specific due to variations in meteorological conditions. Its main value is to indicate seasonal and annual trends in fluoride exposure of vegetation. Subject to these considerations, the lower and upper limits of atmospheric fluoride exposure and the applicability to atmospheric fluoride estimation under routine or emergency fluoride release conditions are discussed, with special emphasis on the limiting factors

In Situ Raman Analyses of Natural Gas and Gas Hydrates at Hydrate Ridge, Oregon

Science.gov (United States)

Peltzer, E. T.; White, S. N.; Dunk, R. M.; Brewer, P. G.; Sherman, A. D.; Schmidt, K.; Hester, K. C.; Sloan, E. D.

2004-12-01

During a July 2004 cruise to Hydrate Ridge, Oregon, MBARI's sea-going laser Raman spectrometer was used to obtain in situ Raman spectra of natural gas hydrates and natural gas venting from the seafloor. This was the first in situ analysis of gas hydrates on the seafloor. The hydrate spectra were compared to laboratory analyses performed at the Center for Hydrate Research, Colorado School of Mines. The natural gas spectra were compared to MBARI gas chromatography (GC) analyses of gas samples collected at the same site. DORISS (Deep Ocean Raman In Situ Spectrometer) is a laboratory model laser Raman spectrometer from Kaiser Optical Systems, Inc modified at MBARI for deployment in the deep ocean. It has been successfully deployed to depths as great as 3600 m. Different sampling optics provide flexibility in adapting the instrument to a particular target of interest. An immersion optic was used to analyze natural gas venting from the seafloor at South Hydrate Ridge ( ˜780 m depth). An open-bottomed cube was placed over the vent to collect the gas. The immersion optic penetrated the side of the cube as did a small heater used to dissociate any hydrate formed during sample collection. To analyze solid hydrates at both South and North Hydrate Ridge ( ˜590 m depth), chunks of hydrate were excavated from the seafloor and collected in a glass cylinder with a mesh top. A stand-off optic was used to analyze the hydrate inside the cylinder. Due to the partial opacity of the hydrate and the small focal volume of the sampling optic, a precision underwater positioner (PUP) was used to focus the laser spot onto the hydrate. PUP is a stand-alone system with three degrees-of-freedom, capable of moving the DORISS probe head with a precision of 0.1 mm. In situ Raman analyses of the gas indicate that it is primarily methane. This is verified by GC analyses of samples collected from the same site. Other minor constituents (such as CO2 and higher hydrocarbons) are present but may be in

Effects of acid rain and liming on the enchytraeid fauna in forest soils

International Nuclear Information System (INIS)

Graefe, U.

1989-01-01

The development of the enchytraeid community has been observed in a Solling beech forest over a period of 11 years. Eight out of 18 formerly established species have disappeared in one decade. The connection to soil chemical changes due to atmospheric deposition is discussed. A comparison of adjoining beech and spruce stands revealed considerably lower species numbers under spruce. The community under beech is developing in the direction of the species community in the spruce stand. Liming affects changes in the dominance structure. Mesophilic species are favoured, acidophilic are repressed. In an oak-beech stand near Hamburg even the recolonization by previously absent species was observed. Liming experiments with 25, 50 and 100 dt CaCO 3 /ha showed decreasing total abundance of enchytraeids proportional to the amount of lime. Species number, diversity and evenness increased with lime treatments up to 50 dt/ha. (orig.)

Ductile flow of methane hydrate

Science.gov (United States)

Durham, W.B.; Stern, L.A.; Kirby, S.H.

2003-01-01

Compressional creep tests (i.e., constant applied stress) conducted on pure, polycrystalline methane hydrate over the temperature range 260-287 K and confining pressures of 50-100 MPa show this material to be extraordinarily strong compared to other icy compounds. The contrast with hexagonal water ice, sometimes used as a proxy for gas hydrate properties, is impressive: over the thermal range where both are solid, methane hydrate is as much as 40 times stronger than ice at a given strain rate. The specific mechanical response of naturally occurring methane hydrate in sediments to environmental changes is expected to be dependent on the distribution of the hydrate phase within the formation - whether arranged structurally between and (or) cementing sediments grains versus passively in pore space within a sediment framework. If hydrate is in the former mode, the very high strength of methane hydrate implies a significantly greater strain-energy release upon decomposition and subsequent failure of hydrate-cemented formations than previously expected.

Subgrade stabilization alternatives to lime and cement.

Science.gov (United States)

2010-04-15

This project involved four distinct research activities, (1) the influence of temperature on lime-stabilized soils, (2) the influence of temperature on cement-stabilized soils (3) temperature modeling of stabilized subgrade and (4) use of calcium chl...

Kinetics of the reaction of iron blast furnace slag/hydrated lime sorbents with SO{sub 2} at low temperatures: effects of the presence of CO{sub 2}, O{sub 2}, and NOx

Energy Technology Data Exchange (ETDEWEB)

Liu, C.F.; Shih, S.M. [Industrial Technological Research Institute, Hsinchu (Taiwan)

2009-09-15

The effects of the presence of CO{sub 2}, O{sub 2}, and NOx in the flue gas on the kinetics of the sulfation of blast furnace slag/hydrated lime sorbents at low temperatures were studied using a differential fixed-bed reactor. When O{sub 2} and NOx were not present simultaneously, the reaction kinetics was about the same as that under the gas mixtures containing SO{sub 2}, H{sub 2}O, and N{sub 2} only, being affected mainly by the relative humidity. The sulfation of sorbents can be described by the surface coverage model and the model equations derived for the latter case. When both O{sub 2} and NOx, were present, the sulfation of sorbents was greatly enhanced, forming a great amount of sulfate in addition to sulfite. The surface coverage model is still valid in this case, but the model equations obtained show a more marked effect of relative humidity and negligible effects of SO{sub 2} concentration and temperature on the reaction. The effect of sorbent composition on the reaction kinetics was entirely represented by the effects of the initial specific surface area (S{sub g0}) and the Ca molar content (M{sup -1}) of sorbent. The initial conversion rate of sorbent increased linearly with increasing S{sub g0}, and the ultimate conversion increased linearly with increasing S{sub g0}M{sup -1}. The model equations obtained in this work are applicable to describe the kinetics of the sulfation of the sorbents in the low-temperature dry and semidry fine gas desulfurization processes either with an upstream NOx, removal unit or without.111

Hydration rate of obsidian.

Science.gov (United States)

Friedman, I; Long, W

1976-01-30

The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95 degrees to 245 degrees C. An expression relating hydration rate to temperature was derived for each sample. The SiO(2) content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents. With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates. If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to +/- 10 percent of the true age over periods as short as several years and as long as millions of years.

Solidification of radioactive waste in a cement/lime mixture

International Nuclear Information System (INIS)

Zhou, H.; Colombo, P.

1984-01-01

The suitability of a cement/lime mixture for use as a solidification agent for different types of wastes was investigated. This work includes studies directed towards determining the wasted/binder compositional field over which successful solidification occurs with various wastes and the measurement of some of the waste from properties relevant to evaluating the potential for the release of radionuclides to the environment. In this study, four types of low-level radioactive wastes were simulated for incorporation into a cement/lime mixture. These were boric acid waste, sodium sulfate wastes, aion exchange resins and incinerator ash. 7 references, 3 figures, 2 tables

Studies of ancient concrete as analogs of cementitious sealing materials for a repository in tuff

Energy Technology Data Exchange (ETDEWEB)

Roy, D.M.; Langton, C.A.

1989-03-01

The durability of ancient cementitious materials has been investigated to provide data applicable to determining the resistance to weathering of concrete materials for sealing a repository for storage of high-level radioactive waste. Because tuff and volcanic ash are used in the concretes in the vicinity of Rome, the results are especially applicable to a waste repository in tuff. Ancient mortars, plasters, and concretes collected from Rome, Ostia, and Cosa dating to the third century BC show remarkable durability. The aggregates used in the mortars, plasters, and concretes included basic volcanic and pyroclastic rocks (including tuff), terra-cotta, carbonates, sands, and volcanic ash. The matrices of ancient cementitious materials have been characterized and classified into four categories: (1) hydraulic hydrated lime and hydrated lime cements, (2) hydraulic aluminous and ferruginous hydrated lime cements ({plus_minus} siliceous components), (3) pozzolana/hydrated lime cements, and (4) gypsum cements. Most of the materials investigated are in category (3). The materials were characterized to elucidate aspects of the technology that produced them and their response to the environmental exposure throughout their centuries of existence. Their remarkable properties are the result of a combination of chemical, mineralogical, and microstructural factors. Their durability was found to be affected by the matrix mineralogy, particle size, and porosity; aggregate type, grading and proportioning; and the methodology of placement. 30 refs.

Evaluation of lime and hydrothermal pretreatments for efficient enzymatic hydrolysis of raw sugarcane bagasse.

Science.gov (United States)

Grimaldi, Maira Prearo; Marques, Marina Paganini; Laluce, Cecília; Cilli, Eduardo Maffud; Sponchiado, Sandra Regina Pombeiro

2015-01-01

Ethanol production from sugarcane bagasse requires a pretreatment step to disrupt the cellulose-hemicellulose-lignin complex and to increase biomass digestibility, thus allowing the obtaining of high yields of fermentable sugars for the subsequent fermentation. Hydrothermal and lime pretreatments have emerged as effective methods in preparing the lignocellulosic biomass for bioconversion. These pretreatments are advantageous because they can be performed under mild temperature and pressure conditions, resulting in less sugar degradation compared with other pretreatments, and also are cost-effective and environmentally sustainable. In this study, we evaluated the effect of these pretreatments on the efficiency of enzymatic hydrolysis of raw sugarcane bagasse obtained directly from mill without prior screening. In addition, we evaluated the structure and composition modifications of this bagasse after lime and hydrothermal pretreatments. The highest cellulose hydrolysis rate (70 % digestion) was obtained for raw sugarcane bagasse pretreated with lime [0.1 g Ca(OH)2/g raw] for 60 min at 120 °C compared with hydrothermally pretreated bagasse (21 % digestion) under the same time and temperature conditions. Chemical composition analyses showed that the lime pretreatment of bagasse promoted high solubilization of lignin (30 %) and hemicellulose (5 %) accompanied by a cellulose accumulation (11 %). Analysis of pretreated bagasse structure revealed that lime pretreatment caused considerable damage to the bagasse fibers, including rupture of the cell wall, exposing the cellulose-rich areas to enzymatic action. We showed that lime pretreatment is effective in improving enzymatic digestibility of raw sugarcane bagasse, even at low lime loading and over a short pretreatment period. It was also demonstrated that this pretreatment caused alterations in the structure and composition of raw bagasse, which had a pronounced effect on the enzymes accessibility to the

Liming effect on P availability from Maardu phosphate rock

International Nuclear Information System (INIS)

Sidlauskas, G.; Masauskas, S.; Ezerinskas, V.

2002-01-01

Thirty years ago phosphate rock from the Maardu deposit was intensively used for soil fertilization in Lithuania. However, the application of finely ground product caused an undesirable dusty operation. Afterwards, a super-phosphate production plant was built in Kedainiai and the use of phosphate rock was completely abandoned. Field experiments with fodder beets and barley were carried out to evaluate the P availability of granulated superphosphate and Maardu phosphate rock. The comparison was made at three acidity levels: a) unlimed acid soil with a high content of Al (pH kcl 4.3-4.4, hydrolytic acidity was 41-44 meq/kg soil), b) soil limed with 0.5n rate CaCO 3 powder limestone based on hydrolytic acidity, and c) soil limed with 1.0n rate CaCO 3 . Two field experiments were carried out with fodder beets. In 1997 the yield increased significantly due to liming. However, no significant yield increases were found due to the application of phosphorus fertilizers. Differences between the effect of superphosphate and phosphate rock were also not observed. This might have been caused by a severe drought during the vegetative growth of plants. In the following year, 1998, a soil with similar acidity was chosen, however it contained even lower amounts of available phosphorus in the arable soil (about 50 mg/kg soil A-L method). In the unlimed soil the yield was low, the effect of superphosphate was better than that of phosphate rock. A good fodder beet yield of 32 to 35 t/ha was obtained and the effect of phosphate rock was better than that of superphosphate at 0.5n CaCO 3 rate. When liming with at the high rate (1.0n CaCO 3 rate according to hydrolytic acidity) the action of phosphate rock declined, and a better yield was obtained with superphosphate. Barley was grown after fodder beets in the 1997 experimental field and the residual effect of superphosphate and phosphate rock was investigated. Weather conditions were favorable for barley growth. Therefore a normal yield

Common bean cultivars response to lime surface application under no tillage systemResposta de cultivares de feijoeiro comum à calagem superficial em semeadura direta

Directory of Open Access Journals (Sweden)

Carlos Alexandre Costa Crusciol

2012-08-01

Full Text Available Soil acidity in no tillage system, if not in high situations, can be neutralized by lime surface application, improving mineral nutrition and crop yield. Aiming to evaluate the agronomic performance of common bean cultivars, to surface lime application, in no tillage system, an experiment was conducted in Oxisol, Botucatu Municipal District, São Paulo State, Brazil. The experimental design was a complete randomized block in split plot with four replications, where the plots were formed by common bean cultivars (Carioca, IAC Carioca Eté, Pérola, IAPAR 81 e Campeão 2 and subplots consisted of surface application of dolomitic limestone (zero, 1.8 t ha-1, 3.6 t ha-1 and 5.4 t ha-1. The surface lime application on the soil occurred in October 2002 and subsequently the sequence millet (spring – beans (summer – oat (autumn-winter were planted under rainfed conditions. Bean cultivars sowing were done on December 17, 2003. It can be concluded that there is influence of cultivars and limestone surface application under no tillage, where IAPAR 81 showed better grain yield with the increase of lime rates, obtaining values of 2,025 kg ha-1 without the lime application to 2,655 kg ha-1 with 5.4 t ha-1 lime rate, obtaining 31% yield increase. A acidez do solo no sistema de semeadura direta, caso não se encontre em situações elevadas, pode ser resolvida com aplicação superficial de calcário, melhorando a nutrição mineral e a produtividade das culturas. Com o objetivo de avaliar o desempenho agronômico de cultivares de feijoeiro, em razão da aplicação superficial de calcário, em semeadura direta, foi realizado um experimento num Latossolo Vermelho distrófico, em Botucatu (SP. O delineamento experimental foi o de blocos casualizados, em esquema de parcelas subdivididas com quatro repetições, onde as parcelas foram formadas por cultivares de feijão comum (Carioca, IAC Carioca Eté, Pérola, IAPAR 81 e Campeão 2 e as subparcelas constitu

Industrial Wastes as Auxiliary Additives to Cement/Lime Stabilization of Soils

OpenAIRE

James, Jijo; Pandian, P. Kasinatha

2016-01-01

Chemical stabilization involves the use of chemical agents for initiating reactions within the soil for modification of its geotechnical properties. Cement and lime stabilization have been the most common stabilization methods adopted for soil treatment. Cement stabilization results in good compressive strengths and is preferred for cohesionless to moderately cohesive soil but loses effectiveness when the soil is highly plastic. Lime stabilization is the most preferred method for plastic clay...

Overview: Nucleation of clathrate hydrates.

Science.gov (United States)

Warrier, Pramod; Khan, M Naveed; Srivastava, Vishal; Maupin, C Mark; Koh, Carolyn A

2016-12-07

Molecular level knowledge of nucleation and growth of clathrate hydrates is of importance for advancing fundamental understanding on the nature of water and hydrophobic hydrate formers, and their interactions that result in the formation of ice-like solids at temperatures higher than the ice-point. The stochastic nature and the inability to probe the small length and time scales associated with the nucleation process make it very difficult to experimentally determine the molecular level changes that lead to the nucleation event. Conversely, for this reason, there have been increasing efforts to obtain this information using molecular simulations. Accurate knowledge of how and when hydrate structures nucleate will be tremendously beneficial for the development of sustainable hydrate management strategies in oil and gas flowlines, as well as for their application in energy storage and recovery, gas separation, carbon sequestration, seawater desalination, and refrigeration. This article reviews various aspects of hydrate nucleation. First, properties of supercooled water and ice nucleation are reviewed briefly due to their apparent similarity to hydrates. Hydrate nucleation is then reviewed starting from macroscopic observations as obtained from experiments in laboratories and operations in industries, followed by various hydrate nucleation hypotheses and hydrate nucleation driving force calculations based on the classical nucleation theory. Finally, molecular simulations on hydrate nucleation are discussed in detail followed by potential future research directions.

Overview: Nucleation of clathrate hydrates

Science.gov (United States)

Warrier, Pramod; Khan, M. Naveed; Srivastava, Vishal; Maupin, C. Mark; Koh, Carolyn A.

2016-12-01

Molecular level knowledge of nucleation and growth of clathrate hydrates is of importance for advancing fundamental understanding on the nature of water and hydrophobic hydrate formers, and their interactions that result in the formation of ice-like solids at temperatures higher than the ice-point. The stochastic nature and the inability to probe the small length and time scales associated with the nucleation process make it very difficult to experimentally determine the molecular level changes that lead to the nucleation event. Conversely, for this reason, there have been increasing efforts to obtain this information using molecular simulations. Accurate knowledge of how and when hydrate structures nucleate will be tremendously beneficial for the development of sustainable hydrate management strategies in oil and gas flowlines, as well as for their application in energy storage and recovery, gas separation, carbon sequestration, seawater desalination, and refrigeration. This article reviews various aspects of hydrate nucleation. First, properties of supercooled water and ice nucleation are reviewed briefly due to their apparent similarity to hydrates. Hydrate nucleation is then reviewed starting from macroscopic observations as obtained from experiments in laboratories and operations in industries, followed by various hydrate nucleation hypotheses and hydrate nucleation driving force calculations based on the classical nucleation theory. Finally, molecular simulations on hydrate nucleation are discussed in detail followed by potential future research directions.

Exogenous origin of hydration on asteroid (16) Psyche: the role of hydrated asteroid families

Science.gov (United States)

Avdellidou, C.; Delbo', M.; Fienga, A.

2018-04-01

Asteroid (16) Psyche, which for a long time was the largest M-type with no detection of hydration features in its spectrum, was recently discovered to have a weak 3-μm band and thus it was eventually added to the group of hydrated asteroids. Its relatively high density, in combination with the high radar albedo, led researchers to classify the asteroid as a metallic object. It is believed that it is possibly a core of a differentiated body, a remnant of `hit-and-run' collisions. The detection of hydration is, in principle, inconsistent with a pure metallic origin for this body. Here, we consider the scenario in which the hydration on its surface is exogenous and was delivered by hydrated impactors. We show that impacting asteroids that belong to families whose members have the 3-μm band can deliver hydrated material to Psyche. We developed a collisional model with which we test all dark carbonaceous asteroid families, which contain hydrated members. We find that the major source of hydrated impactors is the family of Themis, with a total implanted mass on Psyche of the order of ˜1014 kg. However, the hydrated fraction could be only a few per cent of the implanted mass, as the water content in carbonaceous chondrite meteorites, the best analogue for the Themis asteroid family, is typically a few per cent of their mass.

Methane Hydrates: Chapter 8

Science.gov (United States)

Boswell, Ray; Yamamoto, Koji; Lee, Sung-Rock; Collett, Timothy S.; Kumar, Pushpendra; Dallimore, Scott

2008-01-01

Gas hydrate is a solid, naturally occurring substance consisting predominantly of methane gas and water. Recent scientific drilling programs in Japan, Canada, the United States, Korea and India have demonstrated that gas hydrate occurs broadly and in a variety of forms in shallow sediments of the outer continental shelves and in Arctic regions. Field, laboratory and numerical modelling studies conducted to date indicate that gas can be extracted from gas hydrates with existing production technologies, particularly for those deposits in which the gas hydrate exists as pore-filling grains at high saturation in sand-rich reservoirs. A series of regional resource assessments indicate that substantial volumes of gas hydrate likely exist in sand-rich deposits. Recent field programs in Japan, Canada and in the United States have demonstrated the technical viability of methane extraction from gas-hydrate-bearing sand reservoirs and have investigated a range of potential production scenarios. At present, basic reservoir depressurisation shows the greatest promise and can be conducted using primarily standard industry equipment and procedures. Depressurisation is expected to be the foundation of future production systems; additional processes, such as thermal stimulation, mechanical stimulation and chemical injection, will likely also be integrated as dictated by local geological and other conditions. An innovative carbon dioxide and methane swapping technology is also being studied as a method to produce gas from select gas hydrate deposits. In addition, substantial additional volumes of gas hydrate have been found in dense arrays of grain-displacing veins and nodules in fine-grained, clay-dominated sediments; however, to date, no field tests, and very limited numerical modelling, have been conducted with regard to the production potential of such accumulations. Work remains to further refine: (1) the marine resource volumes within potential accumulations that can be

Geotechnical and Physico-Chemical Characterization of Low Lime Fly Ashes

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Arif Ali Baig Moghal

2013-01-01

Full Text Available In order to explore the possibility of using low-lime fly ashes, the physical and chemical properties which have a direct bearing on their geotechnical and geoenvironmental behaviors have been investigated. In this paper, two types of low-lime fly ashes, originating from India, have been used. A brief account of various methods adopted in characterizing their physical, chemical, and geotechnical properties is presented. The relative importance of each of these properties in enhancing the bulk applicability of fly ashes has been brought out.

In-situ gas hydrate hydrate saturation estimated from various well logs at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

Science.gov (United States)

Lee, M.W.; Collett, T.S.

2011-01-01

In 2006, the U.S. Geological Survey (USGS) completed detailed analysis and interpretation of available 2-D and 3-D seismic data and proposed a viable method for identifying sub-permafrost gas hydrate prospects within the gas hydrate stability zone in the Milne Point area of northern Alaska. To validate the predictions of the USGS and to acquire critical reservoir data needed to develop a long-term production testing program, a well was drilled at the Mount Elbert prospect in February, 2007. Numerous well log data and cores were acquired to estimate in-situ gas hydrate saturations and reservoir properties.Gas hydrate saturations were estimated from various well logs such as nuclear magnetic resonance (NMR), P- and S-wave velocity, and electrical resistivity logs along with pore-water salinity. Gas hydrate saturations from the NMR log agree well with those estimated from P- and S-wave velocity data. Because of the low salinity of the connate water and the low formation temperature, the resistivity of connate water is comparable to that of shale. Therefore, the effect of clay should be accounted for to accurately estimate gas hydrate saturations from the resistivity data. Two highly gas hydrate-saturated intervals are identified - an upper ???43 ft zone with an average gas hydrate saturation of 54% and a lower ???53 ft zone with an average gas hydrate saturation of 50%; both zones reach a maximum of about 75% saturation. ?? 2009.

Surface morphology study in high speed milling of soda lime glass

Science.gov (United States)

Konneh, Mohamed; Bagum, Mst. Nasima; Ali, Mohammad Yeakub; Amin, A. K. M. Nurul

2018-05-01

Soda lime glass has a wide range of applications in optical, bio-medical and semi-conductor industries. It is undeniably a challenging task to produce micro finish surface on an amorphous brittle solid like soda lime glass due to its low fracture toughness. In order to obtain such a finish surface, ductile machining has been exploited, as this usually cause's plastic flow which control crack propagation. At sub-micro scale cutting parameters, researchers achieved nano finish surface in micro milling operation using coated tool. However it is possible to enhance the rate of material removal (RMR) of soda lime glass at flexible cutting condition. High speed cutting at micro meter level, extend of thermal softening might be prominent than the strain gradient strengthening. The purpose of this study was to explore the effects of high cutting speed end milling parameters on the surface texture of soda lime glass using uncoated carbide tool. The spindle speed, depth of cut and feed rate were varied from 20,000 to 40,000 rpm, 10 to 30 mm/min and 30 to 50 µm respectively. Mathematical model of roughness has been developed using Response Surface Methodology (RSM). Experimental verification confirmed that surface roughness (Ra) 0.38 µm is possible to achieve at increased RMR, 4.71 mm3/min.

Effects of Lime and Concrete Waste on Vadose Zone Carbon Cycling

DEFF Research Database (Denmark)

Thaysen, Eike Marie; Jessen, Søren; Postma, D.

2014-01-01

In this work we investigate how lime and crushed concrete waste (CCW) affect carbon cycling in the vadose zone and explore whether these amendments could be employed to mitigate climate change by increasing the transport of CO2 from the atmosphere to the groundwater. We use a combination of exper......In this work we investigate how lime and crushed concrete waste (CCW) affect carbon cycling in the vadose zone and explore whether these amendments could be employed to mitigate climate change by increasing the transport of CO2 from the atmosphere to the groundwater. We use a combination...... of experimental and modeling tools to determine ongoing biogeochemical processes. Our results demonstrate that lime and CCW amendments to acid soil contribute to the climate forcing by largely increasing the soil CO2 efflux to the atmosphere. In a series of mesocosm experiments, with barley (Hordeum vulgare L.......) grown on podzolic soil material, we have investigated inorganic carbon cycling through the gaseous and liquid phases and how it is affected by different soil amendments. The mesocosm amendments comprised the addition of 0, 9.6, or 21.2 kg m−2 of crushed concrete waste (CCW) or 1 kg lime m−2. The CCW...

Environment-Friendly Control of Pear Scab and Rust Using Lime Sulfur

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Ju Hoon Cha

2018-03-01

Full Text Available Pear scab and rust are the major diseases causing severe epidemics in organic cultivation of pear trees. Incidences of pear scab and rust were compared in organically managed plots and conventionally managed plots to obtain optimum application schedule of environment-friendly control agents in organically managed plots. Organically cultural practice with 10 time-applications of lime sulfur and Bordeaux mixture showed higher than 40% of control efficacies of pear scab and rust compared to conventionally cultural practice. Organically cultural practice with 8 time-applications of lime sulfur considering weather condition showed higher than 30% of control efficacies of pear scab compared to conventionally cultural practice. The results suggest that proper application of environment-friendly control agents such as lime sulfur considering weather condition will enable effective control of the major diseases for organic cultivation of pear.

Novel understanding of calcium silicate hydrate from dilute hydration

KAUST Repository

Zhang, Lina

2017-05-13

The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10 was conducted for tricalcium silicate (C3S) to interpret long-term hydration process and investigate the formation, structure and properties of C-S-H. Based on results from XRD, IR, SEM, NMR and so forth, loose and dense clusters of C-S-H with analogous C/S ratio were obtained along with the corresponding chemical formulae proposed as Ca5Si4O13∙6.2H2O. Crystalline structure inside C-S-H was observed by TEM, which was allocated at the foil-like proportion as well as the edge of wrinkles of the product. The long-term hydration process of C3S in dilute suspension could be sketchily described as migration of calcium hydroxide and in-situ growth of C-S-H with equilibrium silicon in aqueous solution relatively constant and calcium varied.

Journal of Agriculture, Science and Technology - Vol 10, No 2 (2008)

African Journals Online (AJOL)

The effect of liming an acid nitisol with with either calcite of dolomite on two common bean ( Phaseolus vulgaris L.) varieties differing in aluminium tolerance · EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. EN Mugai, SG Agong, H Matsumoto ...

Formation of submarine gas hydrates

Energy Technology Data Exchange (ETDEWEB)

Soloviev, V.; Ginsburg, G.D. (Reserch Institute of Geology and Mineral Resources of the Ocean ' ' VNII Okeangeologia' ' , St. Petersburg (Russian Federation))

1994-03-01

Submarine gas hydrates have been discoverd in the course of deep-sea drilling (DSDP and ODP) and bottom sampling in many offshore regions. This paper reports on expeditions carried out in the Black, Caspian and Okhotsk Seas. Gas hydrate accumulations were discovered and investigated in all these areas. The data and an analysis of the results of the deep-sea drilling programme suggest that the infiltration of gas-bearing fluids is a necessary condition for gas hydrate accumulation. This is confirmed by geological observations at three scale levels. Firstly, hydrates in cores are usually associated with comparatively coarse-grained, permeable sediments as well as voids and fractures. Secondly, hydrate accumulations are controlled by permeable geological structures, i.e. faults, diapirs, mud volcanos as well as layered sequences. Thirdly, in the worldwide scale, hydrate accumulations are characteristic of continental slopes and rises and intra-continental seas where submarine seepages also are widespread. Both biogenic and catagenic gas may occur, and the gas sources may be located at various distances from the accumulation. Gas hydrates presumably originate from water-dissolved gas. The possibility of a transition from dissolved gas into hydrate is confirmed by experimental data. Shallow gas hydrate accumulations associated with gas-bearing fluid plumes are the most convenient features for the study of submarine hydrate formation in general. These accumulations are known from the Black, Caspian and Okhotsk Seas, the Gulf of Mexico and off northern California. (au) (24 refs.)

Effect of quick lime on physicochemical properties of clay soil

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Bessaim Mohammed Mustapha

2018-01-01

Full Text Available Clay soils are known for their water sensitivity, which causes irreparable damage to any structure built on this type of soil. In order to avoid such problem, it is necessary to use various improvement and stabilization methods such as treatment with lime. This process has been used successfully in the field for decades. The addition of lime generates various physicochemical reactions within the soil such as cation exchange and pozzolanic reactions which are largely responsible for the improvement of the soil in question. This paper presents a study concerning the variation of physicochemical properties of clayey soil with the addition of quicklime at different percentages. Experiments were performed on two clayey soils (CL type in order to investigate the influence of quicklime on Atterberg limits and pH. These tests were carried out in an attempt to study and follow the development and progression of various reactions occurred within the soil with various lime percentages. The results show that the addition of quicklime causes a significant improvement in soil properties by reducing plasticity and thereby improves the soil workability. It can also be found that the addition of lime increase pH of soil, which allow activating pozzolanic reactions who tend to stabilize the soil in question by formation of cementitious compounds. Finally, the pH can be considered as a relevant parameter who allows a better understanding of the reactions that occur in the soil matrix.

The Role of Chromohalobacter on Transport of Lanthanides and Cesium in the Dolomite Mineral System

Energy Technology Data Exchange (ETDEWEB)

Zengotita, Frances [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Emerson, Hilary Palmer [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Wayne State Univ., Detroit, MI (United States); Swanson, Juliet S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reed, Donald T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-12-01

The chemical behavior of actinide series elements and fission products is a concern for the Waste Isolation Pilot Plant repository due to their uncertain mobility in the subsurface salt formation. In this work, we are observing the behavior of the halophilic bacterium, Chromohalobacter, and its effect on the mobility of lanthanides and cesium in the presence of dolomite. Batch and minicolumn experiments were conducted with Cs⁺ and lanthanides (Nd³⁺, Eu³⁺) to quantify potential transport with bacteria. Preliminary results show that Cs does not interact strongly with dolomite or Chromohalobacter, while the lanthanides can interact strongly with both minerals and bacteria depending on which the Ln contacts first.

The growth of Scots pine and the availability of nutrients in old Finnish liming experiments on drained peatlands

International Nuclear Information System (INIS)

Nieminen, M.; Paetilae, A.

1994-01-01

Liming (with applications of 1000 to 8000 kg/ha) had no long- term (1929-1985) effect on the growth of Scots pine on drained oligotrophic peatlands. Liming plus NPK fertilization had a variable effect on the growth of stands. The same treatment could result in a very different response in different experimental areas. Both liming alone and liming plus NPK fertilization increased the calcium, magnesium and nitrogen contents of peat and decreased the C/Nratio and acidity. Liming plus fertilization decreased needle boron and manganese and increased calcium and nitrogen concentrations. The results of peat and needle analysis indicated that the changes in nitrogen availability to trees caused by liming have not been sufficient enough to affect tree growth. It was also concluded that boron deficiency was the main reason for the lowered yield. (26 refs., 6 tabs., 8 figs.) (author)

Lime Stabilization of Fine-Grained Greenlandic Sediments in Relation to Construction Projects

DEFF Research Database (Denmark)

Jørgensen, Anders Stuhr; Ingeman-Nielsen, Thomas; Nielsen, Hans Rasmus

2010-01-01

to the cold climate, and it is therefore of great interest to study possible methods to improve the stability of the fine-grained sediments. This presentation will include results of laboratory studies of lime stabilization on a clay soil from Kangerlussuaq, western Greenland. The result includes tests...... of the optimum lime mixture in relation to both reaction time and temperature influence....

Determination of optimal burning temperature ranges for production of natural hydraulic limes

Czech Academy of Sciences Publication Activity Database

Válek, Jan; van Halem, Eveline; Viani, Alberto; Pérez-Estébanez, Marta; Ševčík, Radek; Šašek, Petr

2014-01-01

Roč. 66, September (2014), s. 771-780 ISSN 0950-0618 R&D Projects: GA MK(CZ) DF11P01OVV010 Keywords : natural hydraulic lime * mechanical properties * calcination * CaO * X-ray diffraction * lime reactivity Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.296, year: 2014 http://www.sciencedirect.com/science/article/pii/S095006181400628X

Reaction Sintering of Mexican Dolomite – Zircon Mixtures

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Rodríguez-Galicia, J. L.

2005-08-01

Full Text Available The present work has been conducted aiming to develop additional phase [Ca3SiO5, Ca2SiO4 and/or Ca3Mg(SiO42]-bonded magnesia refractory materials via reaction sintering of dolomite-zircon mixtures, employing a Mexican dolomite containing an excess of 3 wt% of CaCO3. The study was based on phase equilibrium data extracted from the quaternary system CaO – MgO – SiO2 – ZrO2, to put it more precisely, base on the projection from the MgO-apex of the liquidus surface of the primary crystallization volume of MgO onto the opposite face of the above mentioned quaternary system. The refractory materials designed within this system were obtained by attrition milling, followed by cold isostatic pressing and high temperature reaction sintering. All initial and produced materials were characterized by ICP-AES, XRF, XRD, SEM-EDX, DTA and TG analyses. The results obtained indicated that reaction sintering of dolomite-zircon mixtures is an interesting route to produce MgO-CaZrO3-additional phase refractory materials.

El propósito de este trabajo ha sido obtener materiales refractarios de magnesia, aglomerados con una fase adicional [Ca3SiO5, Ca2SiO4 y/o Ca3Mg(SiO42], mediante la sinterización reactiva de mezclas de dolomita-circón, empleando para ello una dolomita mexicana que contiene un exceso de 3% en peso de CaCO3. El estudio se basa en la información relativa al equilibrio de fases del sistema CaO – MgO – SiO2 – ZrO2. En concreto se usa la proyección, desde el vértice del MgO, de la superficie de liquidus del volumen de cristalización primaria de este, hacia la cara opuesta de sistema cuaternario. Los materiales refractarios diseñados se han obtenido por molienda de atrición, seguida de un prensado isostático en frío y sinterización reactiva a alta temperatura. Todos los materiales, iniciales y finales, han sido caracterizados mediante ICPAES, FRX, DRX, MEB-EDX, ATD y TG. Los resultados obtenidos indican que la sinterizaci

Ocorrência de fungos em sementes de soja produzidas sob calagem e adubação potássica residuais The residual effect of liming and potassium fertilization on the occurrence of fungi in soybean seeds

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H.A.A. Mascarenhas

1995-12-01

Full Text Available Estudou-se o efeito residual da adubação potássica e da calagem sobre a ocorrência de fungos em sementes de soja. O experimento foi instalado com a cultivar IAC-17, no ano agrícola de 1991/92, aplicando doses a lanço de O, 3,5 e 7 t/ha de calcário dolomítico e de 0, 150, 300, 450 e 600 kg/ha de K2O. As sementes colhidas no terceiro ano de cultivo, (1993/94 foram submetidas ao teste de sanidade, pelo método do papel de filtro. Observou-se que a calagem reduziu significativamente a incidência de Phomopsis sp., favorecendo, no entanto, a presença de Aspergillus sp. e de Fusarium sp.. Embora não tenham sido detectadas diferenças significativas, nos tratamentos com calagem, verificou-se redução da incidência de Cercospora kikuchii, Colltotrichum dematium var. truncata e Peronospora manshurica. Apenas a incidência de Phomopsis sp. diminuiu significativamente devido à adubação potássica, sendo menor quando se utilizou a dose de 450 kg/ha de K2O.To study the residual effect of liming and potassium fertilizer on the occurrence of fungi in soybean seeds, an experiment was installed during the 1991/92 growing season, using 0, 3.5 and 7.0 t/ha of dolomitic lime and 0, 150, 300, 450 and 600 kg/ha of K2O in the form of potassium cloride. In 1993/94 (the third year, the harvested seeds were submitted to a seed health test (blotter method. The results showed that liming reduced significantly the incidence of Phomopsis sp. and increased the presence of Aspergillus sp. and Fusarium sp.. Although no significant differences were observed with liming, there was a reduction in the incidence of Cercospora kikuchii, Colletotrichum dematium var. truncala and Peronospora manshurica. Among the fungi found in the seeds, only Phomopsis sp. was significantly reduced by potassium fertilization, the least incidence being observed at the rate of 450 kg/ha.

Ocean acidification does not affect magnesium composition or dolomite formation in living crustose coralline algae, Porolithon onkodes in an experimental system

Science.gov (United States)

Nash, M. C.; Uthicke, S.; Negri, A. P.; Cantin, N. E.

2015-09-01

There are concerns that Mg-calcite crustose coralline algae (CCA), which are key reef builders on coral reefs, will be most susceptible to increased rates of dissolution under higher pCO2 and ocean acidification. Due to the higher solubility of Mg-calcite, it has been hypothesised that magnesium concentrations in CCA Mg-calcite will decrease as the ocean acidifies, and that this decrease will make their skeletons more chemically stable. In addition to Mg-calcite, CCA Porolithon onkodes, the predominant encrusting species on tropical reefs, can have dolomite (Ca0.5Mg0.5CO3) infilling cell spaces which increases their stability. However, nothing is known about how bio-mineralised dolomite formation responds to higher pCO2. Using P. onkodes grown for 3 and 6 months in tank experiments, we aimed to determine (1) if mol % MgCO3 in new crust and new settlement was affected by increasing CO2 levels (365, 444, 676 and 904 μatm), (2) whether bio-mineralised dolomite formed within these time frames, and (3) if so, whether this was effected by CO2. Our results show that there was no significant effect of CO2 on mol % MgCO3 in any sample set, indicating an absence of a plastic response under a wide range of experimental conditions. Dolomite within the CCA cells formed within 3 months and dolomite abundance did not vary significantly with CO2 treatment. While evidence mounts that climate change will impact many sensitive coral and CCA species, the results from this study indicate that reef-building P. onkodes will continue to form stabilising dolomite infill under near-future acidification conditions, thereby retaining its higher resistance to dissolution.

Soil acidification and liming in grassland production and grassland soil fertility in Slovenia

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Jure ČOP

2015-12-01

Full Text Available This paper reviews the evidences on grassland soil acidity and liming in relation to soil processes and herbage production. There is also an outline of the present state of soil acidity and acidity-related traits – contents of organic matter (OM, phosphorus (P and potassium (K in Slovene grassland. In grassland, soil acidification is an ongoing process under humid climate conditions. It is mainly driven by leaching of nutrients, net loss of cations due to retention in livestock products, use of physiologically acid fertilizers, acid rain and N2 fixation. This process is reduced by strong pH buffering capacity of the soil and by physiologically basic fertilizers. Acid grassland soils in Slovenia are widely distributed in spite of the fact that 44% of the total land has developed from a carbonate parent material. Of the 1713 grassland soil samples analysed during 2005-2007 45% were regarded as acid ones (pH < 5.5; in KCl, 57% as soils with very low P status (˂ 6 mg P2O5/100 g soil and 22% as soils with very low K status (˂ 10 mg K2O/100 soil. Increased content of soil organic matter was identified for alpine pastures (˃ 10 % OM in 44% of samples, mainly as a result of low decomposition rate. Liming of acid grassland soils did not always reflect in a higher herbage yield. The cause for this inefficiency is plant composition of grassland. Thus, many grassland plants with relatively high production potential have adapted to acid soil conditions. To illustrate the inconsistent liming effect three researches are reviewed. In the first two researches liming along with fertilizer application did not increase the yield comparing to the fertilized control while in the third research the increase amounted 26 %. Liming improves considerably botanical composition of the acid grassland (e.g. sward where Common Bent – Agrostis tenuis Sibth. – prevails and thus indirectly affects palatability and nutritive value of herbage. Grassland liming has a weak

Characterization of un-hydrated and hydrated BioAggregate™ and MTA Angelus™.

Science.gov (United States)

Camilleri, J; Sorrentino, F; Damidot, D

2015-04-01

BioAggregate™ is a novel material introduced for use as a root-end filling material. It is tricalcium silicate-based, free of aluminium and uses tantalum oxide as radiopacifier. BioAggregate contains additives to enhance the material performance. The purpose of this research was to characterize the un-hydrated and hydrated forms of BioAggregate using a combination of techniques, verify whether the additives if present affect the properties of the set material and compare these properties to those of MTA Angelus™. Un-hydrated and hydrated BioAggregate and MTA Angelus were assessed. Un-hydrated cement was tested for chemical composition, specific surface area, mineralogy and kinetics of hydration. The set material was investigated for mineralogy, microstructure and bioactivity. Scanning electron microscopy, X-ray energy dispersive spectroscopic analysis, X-ray fluorescence spectroscopy, X-ray diffraction and isothermal calorimetry were employed. The specific surface area was investigated using a gas adsorption method with nitrogen as the probe. BioAggregate was composed of tricalcium silicate, tantalum oxide, calcium phosphate and silicon dioxide and was free of aluminium. On hydration, the tricalcium silicate produced calcium silicate hydrate and calcium hydroxide. The former was deposited around the cement grains, while the latter reacted with the silicon dioxide to form additional calcium silicate hydrate. This resulted in reduction of calcium hydroxide in the aged cement. MTA Angelus reacted in a similar fashion; however, since it contained no additives, the calcium hydroxide was still present in the aged cement. Bioactivity was demonstrated by deposition of hydroxyapatite. BioAggregate exhibited a high specific surface area. Nevertheless, the reactivity determined by isothermal calorimetry appeared to be slow compared to MTA Angelus. The tantalum oxide as opposed to bismuth oxide was inert, and tantalum was not leached in solution. BioAggregate exhibited

The effect of dolomite type and Al2O3 content on the phase composition in aluminous cements containing spinel

Directory of Open Access Journals (Sweden)

R. Naghizadeh

2011-06-01

Full Text Available In this paper, the effect of dolomite type and Al2O3 content on the phase composition in aluminous cements containing MA spinel is investigated. For this reason, the raw and calcined dolomites are used as raw materials along with calcined alumina in the preparation of the cement. Then, different compositions are prepared at 1350°C using the sintering method and their mineralogical compositions are investigated using the diffractometric technique. Also, their microstructures arre evaluated. The results indicate that raw materials used have great effect on the type and amount of formed phases in cement composition. Independently of the dolomite type used, a mixed phase product consisting of spinel accompanied by CA and CA2 is obtained. The content of CA phase in the cement composition is decreased with increasing of Al2O3 in the raw materials composition. On the other hand, the content of CA2 phase is increased with the addition of Al2O3. In addition, the results show that the formation of C12A7 is favored by use of calcined dolomite.

Methods to determine hydration states of minerals and cement hydrates

Energy Technology Data Exchange (ETDEWEB)

Baquerizo, Luis G., E-mail: luis.baquerizoibarra@holcim.com [Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland); Matschei, Thomas [Innovation, Holcim Technology Ltd., CH-5113 Holderbank (Switzerland); Scrivener, Karen L. [Laboratory of Construction Materials, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Saeidpour, Mahsa; Thorell, Alva; Wadsö, Lars [Building Materials, Lund University, Box 124, 221 000 Lund (Sweden)

2014-11-15

This paper describes a novel approach to the quantitative investigation of the impact of varying relative humidity (RH) and temperature on the structure and thermodynamic properties of salts and crystalline cement hydrates in different hydration states (i.e. varying molar water contents). The multi-method approach developed here is capable of deriving physico-chemical boundary conditions and the thermodynamic properties of hydrated phases, many of which are currently missing from or insufficiently reported in the literature. As an example the approach was applied to monosulfoaluminate, a phase typically found in hydrated cement pastes. New data on the dehydration and rehydration of monosulfoaluminate are presented. Some of the methods used were validated with the system Na{sub 2}SO{sub 4}–H{sub 2}O and new data related to the absorption of water by anhydrous sodium sulfate are presented. The methodology and data reported here should permit better modeling of the volume stability of cementitious systems exposed to various different climatic conditions.

Methods to determine hydration states of minerals and cement hydrates

International Nuclear Information System (INIS)

Baquerizo, Luis G.; Matschei, Thomas; Scrivener, Karen L.; Saeidpour, Mahsa; Thorell, Alva; Wadsö, Lars

2014-01-01

This paper describes a novel approach to the quantitative investigation of the impact of varying relative humidity (RH) and temperature on the structure and thermodynamic properties of salts and crystalline cement hydrates in different hydration states (i.e. varying molar water contents). The multi-method approach developed here is capable of deriving physico-chemical boundary conditions and the thermodynamic properties of hydrated phases, many of which are currently missing from or insufficiently reported in the literature. As an example the approach was applied to monosulfoaluminate, a phase typically found in hydrated cement pastes. New data on the dehydration and rehydration of monosulfoaluminate are presented. Some of the methods used were validated with the system Na 2 SO 4 –H 2 O and new data related to the absorption of water by anhydrous sodium sulfate are presented. The methodology and data reported here should permit better modeling of the volume stability of cementitious systems exposed to various different climatic conditions

The effect of lime pre-treatments of date palm leaves on delignification and in vitro rumen degradability

NARCIS (Netherlands)

Ghorbani, M.; Ahmadi, F.; Rajaee Rad, A.; Zamiri, M.J.; Cone, J.W.; Polikarpov, I.

2017-01-01

Experiments were conducted to determine the effect of lime pre-treatment on the chemical composition and in vitro rumen degradability of date palm leaves (DPL). Lime pre-treatments, with or without oxygen supply, were applied for 1, 2 and 3 weeks at 25 and 40 °C. Lime was neutralized by the

Archaeomagnetic studies in central Mexico—dating of Mesoamerican lime-plasters

Science.gov (United States)

Hueda-Tanabe, Y.; Soler-Arechalde, A. M.; Urrutia-Fucugauchi, J.; Barba, L.; Manzanilla, L.; Rebolledo-Vieyra, M.; Goguitchaichvili, A.

2004-11-01

For the first time results of an archaeomagnetic study of unburned lime-plasters from Teotihuacan and Tenochtitlan in central Mesoamerica are presented. Plasters made of lime, lithic clasts and water, appear during the Formative Period and were used for a variety of purposes in floors, sculptures, ceramics and supporting media for mural paintings in the Oaxaca and Maya area. In Central Mexico, grinded volcanic scoria rich in iron minerals is incorporated into the lime-plasters mixture. Samples were selected from two archaeological excavation projects in the Teopancazco residential compound of Teotihuacan and the large multi-stage structure of Templo Mayor in Tenochtitlan, where chronological information is available. The intensity of remanent magnetization (natural remanent magnetization (NRM)) and low-field susceptibility are weak reflecting low relative content of magnetic minerals. NRM directions are well grouped and alternating field demagnetization shows single or two-component magnetizations. Rockmagnetic experiments point to fine-grained titanomagnetites with pseudo-single domain behavior. Anisotropy of magnetic susceptibility (AMS) measurements document a depositional fabric, with normal to free-surface minimum AMS axes. Characteristic mean site directions were correlated to the paleosecular variation curve for Mesoamerica. Data from Templo Mayor reflect recent tilting of the structures. Teopancazco mean site declinations show good correspondence with the reference curve, in agreement with the radiocarbon dating. Dates for four stages of Teotihuacan occupancy based on the study of lime-plasters range from AD 350 to 550. A date for a possible Mazapa occupation around AD 850 or 950 is also suggested based on the archaeomagnetic correlation. The archaeomagnetic record of a plaster floor in Teopancazco differed from the other nearby sites pointing to a thermoremanent magnetization; comparison with the reference curve suggests dates around AD 1375 or 1415. The

Study of sticky rice-lime mortar technology for the restoration of historical masonry construction.

Science.gov (United States)

Yang, Fuwei; Zhang, Bingjian; Ma, Qinglin

2010-06-15

Replacing or repairing masonry mortar is usually necessary in the restoration of historical constructions, but the selection of a proper mortar is often problematic. An inappropriate choice can lead to failure of the restoration work, and perhaps even further damage. Thus, a thorough understanding of the original mortar technology and the fabrication of appropriate replacement materials are important research goals. Many kinds of materials have been used over the years in masonry mortars, and the technology has gradually evolved from the single-component mortar of ancient times to hybrid versions containing several ingredients. Beginning in 2450 BCE, lime was used as masonry mortar in Europe. In the Roman era, ground volcanic ash, brick powder, and ceramic chip were added to lime mortar, greatly improving performance. Because of its superior properties, the use of this hydraulic (that is, capable of setting underwater) mortar spread, and it was adopted throughout Europe and western Asia. Perhaps because of the absence of natural materials such as volcanic ash, hydraulic mortar technology was not developed in ancient China. However, a special inorganic-organic composite building material, sticky rice-lime mortar, was developed. This technology was extensively used in important buildings, such as tombs, in urban constructions, and even in water conservancy facilities. It may be the first widespread inorganic-organic composite mortar technology in China, or even in the world. In this Account, we discuss the origins, analysis, performance, and utility in historic preservation of sticky rice-lime mortar. Mortar samples from ancient constructions were analyzed by both chemical methods (including the iodine starch test and the acid attack experiment) and instrumental methods (including thermogravimetric differential scanning calorimetry, X-ray diffraction, Fourier transform infrared, and scanning electron microscopy). These analytical results show that the ancient masonry

Enthalpy of dissociation and hydration number of methane hydrate from the Clapeyron equation

International Nuclear Information System (INIS)

Anderson, Graydon K.

2004-01-01

The enthalpies of the reactions in which methane hydrate is dissociated to methane vapor and either (1) water, or (2) ice are determined by a new analysis using the Clapeyron equation. The difference in enthalpies of the two reactions is used to infer the hydration number at the quadruple point where hydrate, ice, liquid water, and methane vapor coexist. By appropriate corrections, the hydration number at points removed from the quadruple point is also determined. The most important feature of the new analysis is the direct use of the Clapeyron equation. The method avoids the use of certain simplifying assumptions that have compromised the accuracy of previous analyses in which the Clausius-Clapeyron equation was used. The analysis takes into account the finite volumes of all phases, the non-ideality of the vapor phase, and the solubility of methane in water. The results show that the enthalpy of dissociation and hydration number are constant within experimental error over the entire (hydrate, liquid, vapor) coexistence region. The results are more accurate than but entirely consistent with almost all previous studies

Lower Cretaceous Puez key-section in the Dolomites - towards the mid-Cretaceous super-greenhouse

Science.gov (United States)

Lukeneder, A.; Halásová, E.; Rehákova, D.; Józsa, Š.; Soták, J.; Kroh, A.; Jovane, L.; Florindo, F.; Sprovieri, M.; Giorgioni, M.; Lukeneder, S.

2012-04-01

Investigations on different fossil groups in addition to isotopic, paleomagnetic and geochemical analysis are combined to extract the Early Cretaceous history of environmental changes, as displayed by the sea level and climate changes. Results on biostratigraphy are integrated with other dating methods as magnetostraigraphy, correlation and cyclostratigraphy. The main investigation topics of the submitted project within the above-described framework are the biostratigraphic (Lukeneder and Aspmair, 2006, 2012), palaeoecological (Lukeneder, 2008, 2012), palaeobiogeographic, lithostratigraphic (Lukeneder, 2010, 2011), cyclostratigraphic and magnetostratigraphic development of the Early Cretaceous in the Puez area. The main sections occur in expanded outcrops located on the southern margin of the Puez Plateau, within the area of the Puez-Geisler Natural Park, in the northern part of the Dolomites (South Tyrol, North Italy). The cephalopod, microfossil and nannofossil faunas and floras from the marly limestones to marls here indicates Hauterivian to Albian/Cenomanian age. Oxygen isotope values from the Lower Cretaceous Puez Formation show a decreasing trend throughout the log, from -1.5‰ in the Hauterivian to -4.5‰ in the Albian/Cenomanian. The decreasing values mirror an increasing trend in palaeotemperatures from ~ 15-18°C in the Hauterivian up to ~25-30 °C in the Albian/Cenomanian. The trend probably indicates the positive shift in temperature induced by the well known Mid Cretaceous Ocean warming (e.g., Super-Greenhouse). The cooperative project (FWF project P20018-N10; 22 international scientists): An integrative high resolution project. Macro- and microfossils, isotopes, litho-, cyclo-, magneto-and biostratigraphy as tools for investigating the Lower Cretaceous within the Dolomites (Southern Alps, Northern Italy) -The Puez area as a new key region of the Tethyan Realm), is on the way since 2008 by the Natural History Museum in Vienna and the 'Naturmuseum S�

Fire extinction utilizing carbon dioxide hydrate

Energy Technology Data Exchange (ETDEWEB)

Hatakeyama, T.; Aida, E.; Yokomori, T.; Ohmura, R.; Ueda, T. [Keio Univ., Hiyoshi, Kohoku-ku, Yokohama (Japan)

2008-07-01

Clathrate hydrates formed with nonflammable gases may be suitable for use as fire extinguishing agents because dissociation of the hydrates results in the temperature decrease in the combustion field and the nonflammable gases released from the dissociated hydrates prevent the supply of the oxygen to the combustion field. This paper discussed experiments in which ordinary ice and dry ice were used to evaluate the performance of CO{sub 2} hydrate as a fire extinguishing agent. The paper described the apparatus and procedure for the preparation of CO{sub 2} hydrate crystals. A schematic of the reactor to form CO{sub 2} hydrate and a photograph of CO{sub 2} hydrate crystal formed in the study were also presented. Other illustrations, photographs, and tables that were presented included a schematic diagram of the experimental apparatus used for the flame extinction experiments; a photograph of CO{sub 2} hydrate powder; sequential video graphs of the flame extinction by the supply of CO{sub 2} hydrate crystals to the methanol pool flame and the relevant illustration; and heat of CO{sub 2} hydrate dissociation, water vaporization and sublimation of dry ice. It was concluded that the critical mass of the CO{sub 2} hydrate required to extinguish a flame was much less than that of ordinary ice, indicating the superiority of CO{sub 2} hydrate to the ice. In addition, the experiments also revealed that the size of the CO{sub 2} hydrate particles had a significant effect on the performance of flame extinction. 5 refs., 2 tabs., 7 figs.

Hydrates on tap: scientists say natural gas hydrates may be tough nut to crack

Energy Technology Data Exchange (ETDEWEB)

Mahoney, J.

2001-12-01

Gas hydrates are methane molecules trapped in cages of water molecules, yielding a substance with a slushy, sherbet-like consistency. Drilling for hydrates is similar to conventional oil and gas drilling, however, the secret to economic production still remains hidden. Hydrates exist in abundance in such places as deep ocean floor and below ground in some polar regions. The real challenge lies in producing gas from this resource, inasmuch as there is no existing technology for production of gas specifically from methane hydrates. This paper describes an international research program, involving a five-country partnership to spud the first of three wells into the permafrost of the Mackenzie River Delta in the Northwest Territories. The project, worth about $15 million, has brought together public funding and expertise from Japan, Germany, India as well as the Canadian and US Geological Surveys and the US Dept. of Energy in an effort to gain information on the production response of gas hydrates. The operator of the project is Japan Petroleum Exploration Company of Canada, a subsidiary of Japan National Oil Corporation. Since Japan is poor in domestic hydrocarbon resources, but is surrounded by deep water that contains potential for gas hydrates, Japan has a great deal riding on the success of this project. Germany and the United States are also very much interested. Current thinking is that gas is in contact with the hydrates and that it should be possible to develop a free gas reservoir as if it were a conventional deposit. As the free gas is drawn off, the pressure is reduced on the hydrates in contact with it , the hydrates dissociate from the gas and replenish the conventional reservoir. So far this is still only a theory, but it appears to be a sensible approach to hydrate production. 1 photo.

THE ANISIAN MACROFLORA FROM THE NORTHERN DOLOMITES (KÜHWIESENKOPF/ MONTE PRÀ DELLA VACCA, BRAIES: A FIRST REPORT

Directory of Open Access Journals (Sweden)

CARMEN BROGLIO LORIGA

2002-11-01

Full Text Available The knowledge of Triassic macroflora from the Dolomites mostly concerns the Ladinian, while literature data on Anisian plants are scarce. This gap is filled by the discovery, reported here, of a rich plant deposit from Kühwiesenkopf / Monte Prà della Vacca (Prags/Braies Dolomites. The fossils occur in a horizon, about 1 m thick, from the lower part of the Dont Formation, a basinal unit mostly constituted by hemipelagic, terrigenous-carbonatic sediments of Pelsonian - Illyrian age. The stratigrafic interval with the plant horizon is Pelsonian in age. A preliminary systematic analysis of the numerous and well preserved specimens has allowed the identification of at least 17 genera. The taxa belong primarily to the Pteridophyta (Anomopteris, Neuropteridium, Cladophlebis, Crematopteris, ?Marattiopsis, subordinately to the Cycadophyta (Bjuvia, Taeniopteris, Dioonitocarpidium, Pterophyllum / Nilssonia. Coniferophyta are represented by Voltzia, ?Voltzia and Albertia; the latter genus is recorded herein for the first time in the Middle Triassic of the Dolomites. Besides, two Lycophyta genera (?Isoetites, Lycophyta new taxon, three Pteridospermae genera (?Sagenopteris, Scytophyllum and Peltaspermum, and one Sphenophyta genus (Equisetites have also been recognized.   

Effect of liming on the molybdenum content in the root and leaf of ...

African Journals Online (AJOL)

Three liming treatments were employed (1, 3 and 4 t/ha CaCO3). The liming operation used on pseudogley induced a statistically significant increase in molybdenum ion absorption into the root system of tomato. Independently from the aforementioned, the values for the root and leaf molybdenum content of tomato in each ...

Waters of Hydration of Cupric Hydrates: A Comparison between Heating and Absorbance Methods

Science.gov (United States)

Barlag, Rebecca; Nyasulu, Frazier

2011-01-01

The empirical formulas of four cupric hydrates are determined by measuring the absorbance in aqueous solution. The Beer-Lambert Law is verified by constructing a calibration curve of absorbance versus known Cu[superscript 2+](aq) concentration. A solution of the unknown hydrate is prepared by using 0.2-0.3 g of hydrate, and water is added such…

LANDSCAPE ARCHAEOLOGY ALONG LIMES TRANSALUTANUS

Directory of Open Access Journals (Sweden)

Eugen S. Teodor

2014-09-01

Full Text Available The project addresses the historical monuments comprised in the longest Roman ‘linear defence’ structure present on the Romanian territory.Despite it being the longest, this historic structure is the least protected and the least known in its technical details. Was indeed Limes Transalutanus an incomplete limes (lacking civilian settlements, for example, an odd construction (a vallum without fossa, an early-alarm line rather than a proper defensive line? Taking on these historical and archaeological challenges, the team attempts to develop an investigation technology applicable to large scale archaeological landscapes - a full evaluation chain, involving aerial survey, surface survey, geophysical investigation, multispectral images analysis, statistic evaluation and archaeological diggings. This technological chain will be systematically applied on the whole length of the objective, that is, on a 155 km distance. The attempt to find answers to issues related to the earth works’ functionality, layout, structure, chronology and relation with adjacent sites will be grounded on exploring the relations of the monument with the surrounding environment, by focussing on finding methods to reconstruct the features of the ancient landscapes, like systematic drilling, palynological tests and toponymical studies.

Methane hydrate dissociation using inverted five-spot water flooding method in cubic hydrate simulator

International Nuclear Information System (INIS)

Li, Gang; Li, Xiao-Sen; Li, Bo; Wang, Yi

2014-01-01

The combination forms of the hydrate dissociation methods in different well systems are divided into 6 main patterns. Dissociation processes of methane hydrate in porous media using the inverted five-spot water flooding method (Pattern 4) are investigated by the experimental observation and numerical simulation. In situ methane hydrate is synthesized in the Cubic Hydrate Simulator (CHS), a 5.832-L cubic reactor. A center vertical well is used as the hot water injection well, while the four vertical wells at the corner are the gas and water production wells. The gas production begins simultaneously with the hot water injection, while after approximately 20 min of compression, the water begins to be produced. One of the common characteristics of the inverted five-spot water flooding method is that both the gas and water production rates decrease with the reduction of the hydrate dissociation rate. The evaluation of the energy efficiency ratio might indicate the inverted five-spot water flooding as a promising gas producing method from the hydrate reservoir. - Highlights: • A three-dimensional 5.8-L cubic pressure vessel is developed. • Gas production of hydrate using inverted five-spot flooding method is studied. • Water/gas production rate and energy efficiency ratio are evaluated. • Temperature distributions of numerical simulation and experiment agree well. • Hydrate dissociation process is a moving boundary problem in this study

Separation of hemicellulose-derived saccharides from wood hydrolysate by lime and ion exchange resin.

Science.gov (United States)

Wang, Xiaojun; Zhuang, Jingshun; Fu, Yingjuan; Tian, Guoyu; Wang, Zhaojiang; Qin, Menghua

2016-04-01

A combined process of lime treatment and mixed bed ion exchange was proposed to separate hemicellulose-derived saccharides (HDS) from prehydrolysis liquor (PHL) of lignocellulose as value added products. The optimization of lime treatment achieved up to 44.2% removal of non-saccharide organic compounds (NSOC), mainly colloidal substances, with negligible HDS degradation at 0.5% lime level and subsequent neutralization by phosphoric acid. The residual NSOC and calcium ions in lime-treated PHL were eliminated by mixed bed ion exchange. The breakthrough curves of HDS and NSOC showed selective retention toward NSOC, leading to 75% HDS recovery with 95% purity at 17 bed volumes of exchange capacity. In addition, macroporous resin showed higher exchange capacity than gel resin as indicated by the triple processing volume. The remarkable selectivity of the combined process suggested the feasibility for HDS separation from PHL. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microbial communities associated with the anthropogenic, highly alkaline environment of a saline soda lime, Poland

OpenAIRE

Kalwasi?ska, Agnieszka; Felf?ldi, Tam?s; Szab?, Attila; Deja-Sikora, Edyta; Kosobucki, Przemys?aw; Walczak, Maciej

2017-01-01

Soda lime is a by-product of the Solvay soda process for the production of sodium carbonate from limestone and sodium chloride. Due to a high salt concentration and alkaline pH, the lime is considered as a potential habitat of haloalkaliphilic and haloalkalitolerant microbial communities. This artificial and unique environment is nutrient-poor and devoid of vegetation, due in part to semi-arid, saline and alkaline conditions. Samples taken from the surface layer of the lime and from the depth...

Thermophysical properties of hydrophobised lime plasters - The influence of ageing