Field trial of a pulsed limestone diversion well

Science.gov (United States)

Sibrell, Philip L.; Denholm, C.; Dunn, Margaret

2013-01-01

The use of limestone diversion wells to treat acid mine drainage (AMD) is well-known, but in many cases, acid neutralization is not as complete as would be desired. Reasons for this include channeling of the water through the limestone bed, and the slow reaction rate of the limestone gravel. A new approach to improve the performance of the diversion well was tested in the field at the Jennings Environmental Education Center, near Slippery Rock, PA. In this approach, a finer size distribution of limestone was used so as to allow fluidization of the limestone bed, thus eliminating channeling and increasing particle surface area for faster reaction rates. Also, water flow was regulated through the use of a dosing siphon, so that consistent fluidization of the limestone sand could be achieved. Testing began late in the summer of 2010, and continued through November of 2011. Initial system performance during the 2010 field season was good, with the production of net alkaline water, but hydraulic problems involving air release and limestone sand retention were observed. In the summer of 2011, a finer size of limestone sand was procured for use in the system. This material fluidized more readily, but acid neutralization tapered off after several days. Subsequent observations indicated that the hydraulics of the system was compromised by the formation of iron oxides in the pipe leading to the limestone bed, which affected water distribution and flow through the bed. Although results from the field trial were mixed, it is believed that without the formation of iron oxides and plugging of the pipe, better acid neutralization and treatment would have occurred. Further tests are being considered using a different hydraulic configuration for the limestone sand fluidized bed.

Epilithic and endolithic bacterial communities in limestone from a Maya archaeological site.

Science.gov (United States)

McNamara, Christopher J; Perry, Thomas D; Bearce, Kristen A; Hernandez-Duque, Guillermo; Mitchell, Ralph

2006-01-01

Biodeterioration of archaeological sites and historic buildings is a major concern for conservators, archaeologists, and scientists involved in preservation of the world's cultural heritage. The Maya archaeological sites in southern Mexico, some of the most important cultural artifacts in the Western Hemisphere, are constructed of limestone. High temperature and humidity have resulted in substantial microbial growth on stone surfaces at many of the sites. Despite the porous nature of limestone and the common occurrence of endolithic microorganisms in many habitats, little is known about the microbial flora living inside the stone. We found a large endolithic bacterial community in limestone from the interior of the Maya archaeological site Ek' Balam. Analysis of 16S rDNA clones demonstrated disparate communities (endolithic: >80% Actinobacteria, Acidobacteria, and Low GC Firmicutes; epilithic: >50% Proteobacteria). The presence of differing epilithic and endolithic bacterial communities may be a significant factor for conservation of stone cultural heritage materials and quantitative prediction of carbonate weathering.

Factors involved in the selection of limestone reagents for use in wet FGD systems

International Nuclear Information System (INIS)

Jarvis, J.B.; Roothaan, E.S.; Meserole, F.B.; Owens, D.R.

1992-01-01

With recent activity in the design and construction of retrofit flue gas desulfurization (FGD) systems, many utilities are faced with the task of selecting limestones which will allow FGD systems to function as designed, and at the same time, provide cost-effective operation. The Electric Power Research Institute (EPRI) has sponsored research to identify factors which should be considered in the reagent selection process. A set of capabilities has been developed which is currently being employed to assist six utilities in selecting cost-effective reagent sources. The major elements in the selection package consist of an analytical characterization of candidate limestones; grindability, reactivity, and magnesium availability testing; and performance modeling utilizing EPRI's FGD PRocess Integration and Simulation Model (FGDPRISM). The results from these measurements are used to perform a site-specific economic analysis which can be used to rank the candidate limestones and quantify the impact of various limestone properties on plant operating costs. This paper includes a description of each element in the selection package along with a review of current research activities aimed at improving predictions of limestone reactivity and magnesium availability. An example is presented which illustrates how reactivity and magnesium availability affect both the performance of an FGD system and plant operating costs

Differences between silica and limestone concretes that may affect their interaction with corium

International Nuclear Information System (INIS)

Journeau, C.; Haquet, J. F.; Piluso, P.; Bonnet, J. M.

2008-01-01

Recent Molten Core Concrete Interaction tests performed at Argonne National Laboratory and at CEA Cadarache have shown that, whereas the ablation of limestone-rich concretes is almost isotropic, the ablation of silica-rich concretes is much faster towards the sides than towards the bottom of the cavity. The following differences exists between limestone-rich and silica-rich concretes: limestone concretes liberate about twice as much gas, at a given ablation rate than siliceous concretes (more than 50% more at constant heat flux) and this can affect pool hydraulics and crust stability: limestone concrete has a higher liquidus temperature than siliceous concrete and molten limestone concrete has a larger diffusion coefficient and can more easily dissolve a corium crust than siliceous melt; limestone aggregates are destroyed by de-carbonation at around 1000 K while silica aggregates melt only above 2000 K, so that floating silica aggregates can form cold spots increasing corium solidification near the interface; de-carbonation of limestone leads to a significant shrinkage of concrete melt volume compared to the cold solid that hampers the mechanical stability of overlying crusts; the chemical composition of molten mortar (sand + cement) and concrete (sand + gravel + cement) is close for limestone-rich concretes while it is different for siliceous concretes, so that the melt composition may vary significantly in case of non-simultaneous melting of the siliceous concrete constituents; molten silicates have a large viscosity, so that transport properties are different for the two types of concretes. The small range of plant concrete compositions that have been considered for MCCI experiments has not yet been found sufficient to determine which of the above-mentioned differences is paramount to explain the observed difference in ablation patterns. Separate Effect Tests using specially-designed 'artificial concretes' and prototypic corium would provide the necessary

Characterization of limestone reacted with acid-mine drainage in a pulsed limestone bed treatment system at the Friendship Hill National Historical Site, Pennsylvania, USA

Science.gov (United States)

Hammarstrom, J.M.; Sibrell, P.L.; Belkin, H.E.

2003-01-01

Armoring of limestone is a common cause of failure in limestone-based acid-mine drainage (AMD) treatment systems. Limestone is the least expensive material available for acid neutralization, but is not typically recommended for highly acidic, Fe-rich waters due to armoring with Fe(III) oxyhydroxide coatings. A new AMD treatment technology that uses CO2 in a pulsed limestone bed reactor minimizes armor formation and enhances limestone reaction with AMD. Limestone was characterized before and after treatment with constant flow and with the new pulsed limestone bed process using AMD from an inactive coal mine in Pennsylvania (pH = 2.9, Fe = 150 mg/l, acidity = 1000 mg/l CaCO3). In constant flow experiments, limestone is completely armored with reddish-colored ochre within 48 h of contact in a fluidized bed reactor. Effluent pH initially increased from the inflow pH of 2.9 to over 7, but then decreased to 6 during operation. Limestone removed from a pulsed bed pilot plant is a mixture of unarmored, rounded and etched limestone grains and partially armored limestone and refractory mineral grains (dolomite, pyrite). The ???30% of the residual grains in the pulsed flow reactor that are armored have thicker (50- to 100-??m), more aluminous coatings and lack the gypsum rind that develops in the constant flow experiment. Aluminium-rich zones developed in the interior parts of armor rims in both the constant flow and pulsed limestone bed experiments in response to pH changes at the solid/solution interface. ?? 2003 Elsevier Ltd. All rights reserved.

Biotin- and Glycoprotein-Coated Microspheres as Surrogates for Studying Filtration Removal of Cryptosporidium parvum in a Granular Limestone Aquifer Medium.

Science.gov (United States)

Stevenson, M E; Blaschke, A P; Toze, S; Sidhu, J P S; Ahmed, W; van Driezum, I H; Sommer, R; Kirschner, A K T; Cervero-Aragó, S; Farnleitner, A H; Pang, L

2015-07-01

Members of the genus Cryptosporidium are waterborne protozoa of great health concern. Many studies have attempted to find appropriate surrogates for assessing Cryptosporidium filtration removal in porous media. In this study, we evaluated the filtration of Cryptosporidium parvum in granular limestone medium by the use of biotin- and glycoprotein-coated carboxylated polystyrene microspheres (CPMs) as surrogates. Column experiments were carried out with core material taken from a managed aquifer recharge site in Adelaide, Australia. For the experiments with injection of a single type of particle, we observed the total removal of the oocysts and glycoprotein-coated CPMs, a 4.6- to 6.3-log10 reduction of biotin-coated CPMs, and a 2.6-log10 reduction of unmodified CPMs. When two different types of particles were simultaneously injected, glycoprotein-coated CPMs showed a 5.3-log10 reduction, while the uncoated CPMs displayed a 3.7-log10 reduction, probably due to particle-particle interactions. Our results confirm that glycoprotein-coated CPMs are the most accurate surrogates for C. parvum; biotin-coated CPMs are slightly more conservative, while unmodified CPMs are markedly overly conservative for predicting C. parvum removal in granular limestone medium. The total removal of C. parvum observed in our study suggests that granular limestone medium is very effective for the filtration removal of C. parvum and could potentially be used for the pretreatment of drinking water and aquifer storage recovery of recycled water. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

NNLOPS accurate predictions for $W^+W^-$ production arXiv

CERN Document Server

Re, Emanuele; Zanderighi, Giulia

We present novel predictions for the production of $W^+W^-$ pairs in hadron collisions that are next-to-next-to-leading order accurate and consistently matched to a parton shower (NNLOPS). All diagrams that lead to the process $pp\\to e^- \\bar \

ASTRAL, DRAGON and SEDAN scores predict stroke outcome more accurately than physicians.

Science.gov (United States)

Ntaios, G; Gioulekas, F; Papavasileiou, V; Strbian, D; Michel, P

2016-11-01

ASTRAL, SEDAN and DRAGON scores are three well-validated scores for stroke outcome prediction. Whether these scores predict stroke outcome more accurately compared with physicians interested in stroke was investigated. Physicians interested in stroke were invited to an online anonymous survey to provide outcome estimates in randomly allocated structured scenarios of recent real-life stroke patients. Their estimates were compared to scores' predictions in the same scenarios. An estimate was considered accurate if it was within 95% confidence intervals of actual outcome. In all, 244 participants from 32 different countries responded assessing 720 real scenarios and 2636 outcomes. The majority of physicians' estimates were inaccurate (1422/2636, 53.9%). 400 (56.8%) of physicians' estimates about the percentage probability of 3-month modified Rankin score (mRS) > 2 were accurate compared with 609 (86.5%) of ASTRAL score estimates (P DRAGON score estimates (P DRAGON score estimates (P DRAGON and SEDAN scores predict outcome of acute ischaemic stroke patients with higher accuracy compared to physicians interested in stroke. © 2016 EAN.

Effect of limestone particle size and calcium to non-phytate phosphorus ratio on true ileal calcium digestibility of limestone for broiler chickens.

Science.gov (United States)

Anwar, M N; Ravindran, V; Morel, P C H; Ravindran, G; Cowieson, A J

2016-10-01

The purpose of this study was to determine the effect of limestone particle size and calcium (Ca) to non-phytate phosphorus (P) ratio on the true ileal Ca digestibility of limestone for broiler chickens. A limestone sample was passed through a set of sieves and separated into fine (digestibility of Ca was calculated using the indicator method and corrected for basal endogenous losses to determine the true Ca digestibility. The basal ileal endogenous Ca losses were determined to be 127 mg/kg of dry matter intake. Increasing Ca:non-phytate P ratios reduced the true Ca digestibility of limestone. The true Ca digestibility coefficients of limestone with Ca:non-phytate P ratios of 1.5, 2.0 and 2.5 were 0.65, 0.57 and 0.49, respectively. Particle size of limestone had a marked effect on the Ca digestibility, with the digestibility being higher in coarse particles (0.71 vs. 0.43).

Neutron activation analysis of limestone objects

International Nuclear Information System (INIS)

Meyers, P.; Van Zelst, L.

1977-01-01

The elemental composition of samples from limestone objects were determined by neutron activation analysis to investigate whether this technique can be used to distinguish between objects made of limestone from different sources. Samples weighing between 0.2-2 grams were obtained by drilling from a series of ancient Egyptian and medieval Spanish objects. Analysis was performed on aliquots varying in weight from 40-100 milligrams. The following elements were determined quantitatively: Na, K, Rb, Cs, Ba, Sc, La, Ce, Sm, Eu, Hf, Th, Ta, Cr, Mn, Fe, Co and Zn. The data on Egyptian limestones indicate that, because of the inhomogeneous nature of the stone, 0.2-2 gram samples may not be representative of an entire object. Nevertheless, multivariate statistical methods produced a clear distinction between objects originating from the Luxor area (ancient Thebes) and objects found north of Luxor. The Spanish limestone studied appeared to be more homogeneous. Samples from stylistically related objects have similar elemental compositions while relative large differences were observed between objects having no relationship other than the common provenance of medieval Spain. (orig.) [de

Performance of portland limestone cements: Cements designed to be more sustainable that include up to 15% limestone addition

Science.gov (United States)

Barrett, Timothy J.

In 2009, ASTM and AASHTO permitted the use of up to 5% interground limestone in ordinary portland cement (OPC) as a part of a change to ASTM C150/AASHTO M85. When this work was initiated a new proposal was being discussed that would enable up to 15% interground limestone cement to be considered in ASTM C595/AASHTO M234. This work served to provide rapid feedback to the state department of transportation and concrete industry for use in discussions regarding these specifications. Since the time this work was initiated, ASTM C595/AASHTO M234 was passed (2012c) and PLCs are now able to be specified, however they are still not widely used. The proposal for increasing the volume of limestone that would be permitted to be interground in cement is designed to enable more sustainable construction, which may significantly reduce the CO2 that is embodied in the built infrastructure while also extending the life of cement quarries. Research regarding the performance of cements with interground limestone has been conducted by the cement industry since these cements became widely used in Europe over three decades ago, however this work focuses on North American Portland Limestone Cements (PLCs) which are specifically designed to achieve similar performance as the OPCs they replace.This thesis presents a two-phase study in which the potential for application of cements containing limestone was assessed. The first phase of this study utilized a fundamental approach to determine whether cement with up to 15% of interground or blended limestone can be used as a direct substitute to ordinary portland cement. The second phase of the study assessed the concern of early age shrinkage and cracking potential when using PLCs, as these cements are typically ground finer than their OPC counterparts. For the first phase of the study, three commercially produced PLCs were obtained and compared to three commercially produced OPCs made from the same clinker. An additional cement was tested

Improvement of operational properties of shell limestone building materials by polysulfide solution impregnation

Directory of Open Access Journals (Sweden)

MASSALIMOV Ismail Alexandrovich

2017-06-01

Full Text Available The data of studies on the effectiveness of impregnation with polysulfide solutions of shell limestone used as facing and wall material, as well as for the manufacture of road products are presented. Modification of the limestone with the impregnating composition «Akvastat» created by the authors which is sulfur-containing water-based solution of calcium polysulfide containing alcohols and surfactants, can significantly reduce water absorption and increase durability of limestone. Impregnating composition on the basis of calcium polysulfide possesses density of 1.22–1.24 g/cm3, the infiltrant penetrates into the pore structure of limestone to a depth of 4 cm or more, depending on the density and structure of the sample. While the material is drying, sulfur nanoparticles are crystallized from the polysulfide solution in its pores. They partially fill pore space and form protective durable insoluble hydrophobic coating that impedes the penetration of water into the pores of the limestone, but preserves its vapor permeability, which is important for wall and decoration materials. The evaluation of protective coatings was performed with laser particle size analyzer, scanning probe microscope and a diffractometer. It showed that the average size of the particles forming the protective coating is in the range of 20–25 nm, the particles shape is spherical, the particles are elemental sulfur with orthorhombic structure of the crystal lattice. The processing of shell limestone with calcium polysulphide solution provides formation of coating based on nanosized sulfur on the surface of stone pores. The coating partially fills the pore space and, as it is hydrophobic, reduces the water absorption of the samples by a factor of 5–8, increases their average density by 22–27%, strength in 1,2–1,3 times, the softening factor by 6–19%, that makes possible to predict the increase of the durability of building materials based on shell limestone to 1

Effects of limestone petrography and calcite microstructure on OPC clinker raw meals burnability

Science.gov (United States)

Galimberti, Matteo; Marinoni, Nicoletta; Della Porta, Giovanna; Marchi, Maurizio; Dapiaggi, Monica

2017-10-01

Limestone represents the main raw material for ordinary Portland cement clinker production. In this study eight natural limestones from different geological environments were chosen to prepare raw meals for clinker manufacturing, aiming to define a parameter controlling the burnability. First, limestones were characterized by X-Ray Fluorescence, X-Ray Powder Diffraction and Optical Microscopy to assess their suitability for clinker production and their petrographic features. The average domains size and the microstrain of calcite were also determined by X-Ray Powder Diffraction line profile analysis. Then, each limestone was admixed with clay minerals to achieve the adequate chemical composition for clinker production. Raw meals were thermally threated at seven different temperatures, from 1000 to 1450 °C, to evaluate their behaviour on heating by ex situ X-Ray Powder Diffraction and to observe the final clinker morphology by Scanning Electron Microscopy. Results indicate the calcite microstrain is a reliable parameter to predict the burnability of the raw meals, in terms of calcium silicates growth and lime consumption. In particular, mixtures prepared starting from high-strained calcite exhibit a better burnability. Later, when the melt appears this correlation vanishes; however differences in the early burnability still reflect on the final clinker composition and texture.

Modeling the influence of limestone addition on cement hydration

Directory of Open Access Journals (Sweden)

Ashraf Ragab Mohamed

2015-03-01

Full Text Available This paper addresses the influence of using Portland limestone cement “PLC” on cement hydration by characterization of its microstructure development. The European Standard EN 197-1:2011 and Egyptian specification ESS 4756-1/2009 permit the cement to contain up to 20% ground limestone. The computational tools assist in better understanding the influence of limestone additions on cement hydration and microstructure development to facilitate the acceptance of these more economical and ecological materials. μic model has been developed to enable the modeling of microstructural evolution of cementitious materials. In this research μic model is used to simulate both the influence of limestone as fine filler, providing additional surfaces for the nucleation and growth of hydration products. Limestone powder also reacts relatively slow with hydrating cement to form monocarboaluminate (AFmc phase, similar to the mono-sulfoaluminate (AFm phase formed in ordinary Portland cement. The model results reveal that limestone cement has accelerated cement hydration rate, previous experimental results and computer model “cemhyd3d” are used to validate this model.

Mechanical Analysis Of Limestone In Jaya, Lhong, And Lhoknga

Directory of Open Access Journals (Sweden)

Raihan .

2012-09-01

Full Text Available Research about mechanical analysis of limestone in District Jaya, Lhong, and Lhoknga has been done from Dec. 2011 to Mei 2012. This study aim is to classify the limestones based on physical and mechanical tests as well as identify opportunities limestone utilization in accordance with the SII 0378-80 as a condition of quality natural stone for building. Research have been done by testing compressive strength, modulus Young, wear, specific gravity, porosity, and absorption. The result shows that the limestones are qualified natural stone for building the foundation, curbstone, stone and ornamental stone or paste.

The Influence of Combustion-derived pollutants on limestone deterioration

DEFF Research Database (Denmark)

Johnson, J.B.; Montgomery, Melanie; Thompson, G.E.

1996-01-01

The wet deposition of combustion-derived atmospheric pollutant species, on to freshly cut or diesel-smoked Portland and Monks Park limestone and marble samples, was carried out in a laboratory 'wetting and drying' salt spray chamber for 84 days. Along with the effect of CO2-equilibrated de...... limestones, respectively. Thus the water and hydrogen ion loading effects are significant, as well as the limestone type, but the nature of the anion is not, under the given wetting and drying regime. Further work showed that the increased resistance of marble over that of limestone, to calcium loss...

A Metagenomic Survey of Limestone Hill in Taiwan

Science.gov (United States)

Hsu, Y. W.; Li, K. Y.; Chen, Y. W.; Huang, T. Y.; Chen, W. J.; Shih, Y. J.; Chen, J. S.; Fan, C. W.; Hsu, B. M.

2016-12-01

The limestone of Narro-Sky in Tainliao, Taiwan is of Pleistocene reef limestones interbedded in clastic layers that covered the Takangshan anticlines. Understanding how microbial relative abundance was changed in response to changes of environmental factors may contribute to better comprehension of roles that microorganisms play in altering the landscape structures. In this study, microorganisms growing on the wall of limestone, in the water dripping from the limestone wall and of soil underneath the wall were collected from different locations where the environmental factors such as daytime illumination, humidity, or pH are different. Next generation sequencing (NGS) was carried out to examine the compositions and richness of microbial community. The metagenomics were clustered into operational taxonomic units (OTUs) to analyze relative abundance, diversities and principal coordinates analysis (PCoA). Our results showed the soil sample has the highest alpha diversity while water sample has the lowest. Four major phyla, which are Proteobacteria, Acidobacteria, Actinobacteria, and Cyanobacteria, account for 80 % of total microbial biomass in all groups. Cyanobacteria were found most abundantly in limestone wall instead of water or soil of weathering limestone. The PCoA dimensional patterns of each phylum showed a trace of microbial community dynamic changes, which might be affected by environmental factors. This study provides the insights to understand how environmental factors worked together with microbial community to shape landscape structures.

Performance of japanese quails fed feeds containing different corn and limestone particle sizes

Directory of Open Access Journals (Sweden)

DA Berto

2007-09-01

Full Text Available This study aimed at evaluating performance and egg quality of Japanese quails fed feeds containing different corn and limestone particle sizes. A total number of 648 birds in the peak of production was distributed in a random complete block experimental design, using a 2x3 factorial arrangement (2 corn particle sizes and 3 limestone particle sizes. Birds were designated to one of two blocks, with six replicates of 18 birds each. Mean geometric diameter (MGD values used were 0.617mm and 0.723mm (corn fine and coarse particle sizes, respectively, and 0.361mm, 0.721mm, and 0.947mm (limestone fine, intermediate and coarse particle sizes, respectively. The following treatments were applied: T1: fine corn feed, with 100% fine limestone; T2: fine corn feed, with 50% fine limestone and 50% intermediate limestone; T3: fine corn feed, with 50% fine limestone and 50% coarse limestone; T4: coarse corn feed, with 100% fine limestone; T5: coarse corn feed, with 50% fine limestone and 50% intermediate limestone; T6: coarse corn feed, with 50% fine limestone and 50% coarse limestone. The experiment lasted 112 days, consisting of 4 cycles of 28 days. No significant interaction was observed among corn and limestone particle sizes for any of the analyzed parameters. There were no significant effects (p>0.05 of the tested corn particle sizes on quail performance or egg quality. There were significant (p<0.05 isolated effects of limestone particle size only on the percentage of cracked eggs, which was reduced when birds fed 50% coarse limestone (0.947mm and 50% fine limestone (0.361mm as compared to those fed 100% fine limestone. Therefore, the inclusion of 50% coarse limestone (0.947mm is recommended for quail egg production.

Report of investigation on underground limestone mines in the Ohio region

International Nuclear Information System (INIS)

Byerly, D.W.

1976-06-01

The following is a report of investigation on the geologic setting of several underground limestone mines in Ohio other than the PPG mine at Barberton, Ohio. Due to the element of available time, the writer is only able to deliver a brief synopsis of the geology of three sites visited. These three sites and the Barberton, Ohio site are the only underground limestone mines in Ohio to the best of the writer's knowledge. The sites visited include: (1) the Jonathan Mine located near Zanesville, Ohio, and currently operated by the Columbia Cement Corporation; (2) the abandoned Alpha Portland Cement Mine located near Ironton, Ohio; and (3) the Lewisburg Mine located at Lewisburg, Ohio, and currently being utilized as an underground storage facility. Other remaining possibilities where limestone is being mined underground are located in middle Ordovician strata near Carntown and Maysville, Kentucky. These are drift mines into a thick sequence of carbonates. The writer predicts, however, that these mines would have some problems with water due to the preponderance of carbonate rocks and the proximity of the mines to the Ohio River. None of the sites visited nor the sites in Kentucky have conditions comparable to the deep mine at Barberton, Ohio

Towards cycle-accurate performance predictions for real-time embedded systems

NARCIS (Netherlands)

Triantafyllidis, K.; Bondarev, E.; With, de P.H.N.; Arabnia, H.R.; Deligiannidis, L.; Jandieri, G.

2013-01-01

In this paper we present a model-based performance analysis method for component-based real-time systems, featuring cycle-accurate predictions of latencies and enhanced system robustness. The method incorporates the following phases: (a) instruction-level profiling of SW components, (b) modeling the

Accurate Prediction of Motor Failures by Application of Multi CBM Tools: A Case Study

Science.gov (United States)

Dutta, Rana; Singh, Veerendra Pratap; Dwivedi, Jai Prakash

2018-02-01

Motor failures are very difficult to predict accurately with a single condition-monitoring tool as both electrical and the mechanical systems are closely related. Electrical problem, like phase unbalance, stator winding insulation failures can, at times, lead to vibration problem and at the same time mechanical failures like bearing failure, leads to rotor eccentricity. In this case study of a 550 kW blower motor it has been shown that a rotor bar crack was detected by current signature analysis and vibration monitoring confirmed the same. In later months in a similar motor vibration monitoring predicted bearing failure and current signature analysis confirmed the same. In both the cases, after dismantling the motor, the predictions were found to be accurate. In this paper we will be discussing the accurate predictions of motor failures through use of multi condition monitoring tools with two case studies.

Direct sulfation of limestone based on oxy-fuel combustion technology

Energy Technology Data Exchange (ETDEWEB)

Chen, C.M.; Zhao, C.S.; Liu, S.T.; Wang, C.B. [North China Electric Power University, Baoding (China)

2009-10-15

With limestone as the sorbent, the sulfation reaction can proceed via two different routes depending on whether calcination of the limestone takes place under the given reaction conditions. The direct sulfation reaction is defined as the sulfation reaction between sulfur dioxide (SO{sub 2}) and limestone in an uncalcined state. This reaction, based on oxyfuel combustion technology, was studied by thermogravimetric analysis. Surface morphologies of the limestone particles after sulfation were examined by a scanning electron microscope. Results show that there are more pores or gaps in the product layer formed by direct sulfation of limestone than by indirect sulfation, which can be attributed to the generation of carbon dioxide (CO{sub 2}) at a reaction interface. Compared with indirect sulfation, direct sulfation of limestone can yield much higher conversion and has a much higher reaction rate. For direct sulfation, the greater porosity in the product layer greatly reduces the solid-state ion diffusion distance, resulting in a higher reaction rate and higher conversion.

The chemometric study of limestone physico-chemical properties and thermal behavior for application in construction composites

Directory of Open Access Journals (Sweden)

Radulović Dragan

2017-01-01

Full Text Available The limestone, as an economically sustainable and easily available basic raw material, is frequently utilized in the building industry for resolving of the environmental protection issues. The limestone is incorporated in a cementitious system either by grinding with cement clinker, or by blending with the binder during concrete production. The employing of powdery limestone as partial cement replacement gives the construction composites with properties comparable to that of conventional concrete. The study of limestone thermal behavior and its chemistry is crucial for the prognosis of the designed composites properties. In this work, the instrumental techniques (atomic emission spectroscopy, differential thermal and thermo-gravimetric analysis, Fourier transform infrared spectroscopy and the Principal component analysis were employed to discriminate and classify 22 limestone types. The PCA statistical method, as a means of spectra and experimental data fingerprinting, grouped the samples in a multi-dimensional factor space producing four graphical prognosis - one for each instrumental method. DTA/TG peak values varied the most in a short range between 830-870°C, while FTIR spectra showed the highest diversity in the 867-887 cm-1 and 1237-1647 cm-1 ranges. This research was governed by an idea to reveal whether it is possible to differentiate various limestone types and to predict the possibility of their employment in construction composites on the basis of the results of instrumental and mathematical analyses. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON 172057, III 45008, TR 31055, TR 34006, and TR 34013

The behavior limestone under explosive load

Science.gov (United States)

Orlov, M. Yu; Orlova, Yu N.; Bogomolov, G. N.

2016-11-01

Limestone behavior under explosive loading was investigated. The behavior of the limestone by the action of the three types of explosives, including granular, ammonite and emulsion explosives was studied in detail. The shape and diameter of the explosion craters were obtained. The observed fragments after the blast have been classified as large, medium and small fragments. Three full-scale experiments were carried out. The research results can be used as a qualitative test for the approbation of numerical methods.

Converting SDAP into gypsum in a wet limestone scrubber

Energy Technology Data Exchange (ETDEWEB)

Fogh, F [Faelleskemikerne, Elsamprojekt A/S, Fredericia (Denmark)

1996-12-01

The ELSAM power pool has an installed electrical capacity of approx. 5 GW{sub e}, mainly firing import coal. The major base load units are equipped with desulphurization units and three different desulphurization technologies are used: the wet limestone gypsum process, the spray dry absorption process and a sulphuric acid process. Gypsum and sulphuric acid are commercialized, whereas it has been difficult to utilize the spray dry absorption product (SDAP). The main constituents of SDAP are calcium sulphide, calcium chloride, hydrated lime and impurities mainly originating from fly ash. Sulphide can be oxidized into sulphate in acidic solution - the reaction is utilized in the wet limestone gypsum process - and the possibility of using any spare capacity in the wet limestone gypsum units to oxidize the sulphide content of SDAP into sulphate and produce usable gypsum has been investigated in the laboratory and in a 400 MW{sub e} equivalent wet limestone unit. The limestone inhibition effect of the addition of SDAP is currently being studied in the laboratory in order to determine the effect of different SDAP types (plant/coal sources) on limestone reactivity before further long-term full-scale tests are performed and permanent use of the process planned. (EG)

Characterization of chlorinated solvent contamination in limestone using innovative FLUTe® technologies in combination with other methods in a line of evidence approach

DEFF Research Database (Denmark)

Broholm, Mette Martina; Janniche, Gry Sander; Mosthaf, Klaus

2016-01-01

Characterization of dense non-aqueous phase liquid (DNAPL) source zones in limestone aquifers/bedrock is essential to develop accurate site-specific conceptual models and perform risk assessment. Here innovative field methods were combined to improve determination of source zone architecture......, hydrogeology and contaminant distribution. The FACT™ is a new technology and it was applied and tested at a contaminated site with a limestone aquifer, together with a number of existing methods including wire-line coring with core subsampling, FLUTe® transmissivity profiling and multilevel water sampling...... groundwater sampling (under two flow conditions) and FACT™ sampling and analysis combined with FLUTe® transmissivity profiling and modeling were used to provide a line of evidence for the presence of DNAPL, dissolved and sorbed phase contamination in the limestone fractures and matrix. The combined methods...

Effect of limestone particle size on bone quality characteristics of ...

African Journals Online (AJOL)

A study was conducted to determine the effect of different limestone particle sizes in layer diets on bone quality characteristics at end-of-lay hens. Calcitic limestone (360 g Ca/kg DM) that is extensively used in commercial poultry diets was obtained from a specific South African source. Limestone particles were graded as ...

Model of fragmentation of limestone particles during thermal shock and calcination in fluidised beds

Energy Technology Data Exchange (ETDEWEB)

Saastamoinen, J.; Pikkarainen, T.; Tourunen, A.; Rasanen, M.; Jantti, T. [VTT Technical Research Center, Jyvaskyla (Finland)

2008-11-15

Fragmentation of limestone due to thermal shock and calcination in a fluidised bed was studied through experiments and modelling. The time for heating was estimated by model calculations and the time for calcination by measurements. Fragmentation due to thermal shock was carried out by experiments in a CO{sub 2} atmosphere in order to prevent the effect of calcination. It was found to be much less than fragmentation due to calcination. Average particle sizes before and after fragmentation are presented for several types of limestone. The effects of particle size and gas composition on the primary fragmentation were studied through experiments. Increasing the fluidisation velocity increased the tendency to fragment. The evolution of the particle size distribution (PSD) of limestone particles due to thermal shock and during calcination (or simultaneous calcination and sulphation) were calculated using a population balance model. Fragmentation due to thermal shock is treated as an instantaneous process. The fragmentation frequency during calcination is presented as exponentially decaying over time. In addition to the final PSD, this model also predicts the PSD during the calcination process. The fragmentation was practically found to end after 10 min. Furthermore. a population balance method to calculate the particle size distribution and amount of limestone in fluidised beds in dynamic and steady state, when feeding history is known, is presented.

Rock mass characterization for tunnels in the Copenhagen limestone

DEFF Research Database (Denmark)

Foged, Niels Nielsen; Jakobsen, Lisa; Jackson, Peter

2007-01-01

Tunnels in Copenhagen are drilled through highly anisotropic limestone comprising alternating strongly lithified and less lithified parts. The mass quality of the limestone is usually defined from fracture spacing registered in core samples. The deposit is, however, affected destructively by dril...... by drilling activity yielding a low Rock Quality Designation RQD. In-situ observations of the limestone in excavations or televiewer logs reveal only few natural discontinuities compared to core logging, indicating a very good suitability for tunneling....

Upper Triassic limestones from the northern part of Japan: new insights on the Panthalassa Ocean and Hokkaido Island

Science.gov (United States)

Peyrotty, Giovan; Peybernes, Camille; Ueda, Hayato; Martini, Rossana

2017-04-01

In comparison with the well-known Tethyan domain, Upper Triassic limestones from the Panthalassa Ocean are still poorly known. However, these carbonates represent a unique opportunity to have a more accurate view of the Panthalassa Ocean during the Triassic. Their study will allow comparison and correlation of biotic assemblages, biostratigraphy, diagenesis, and depositional settings of different Triassic localities from Tethyan and Panthalassic domains. Moreover, investigation of these carbonates will provide data for taxonomic revisions and helps to better constrain palaeobiogeographic models. One of the best targets for the study of these carbonates is Hokkaido Island (north of Japan). Indeed, this island is a part of the South-North continuity of Jurassic to Paleogene accretionary complexes, going from the Philippines to Sakhalin Island (Far East Russia). Jurassic and Cretaceous accretionary complexes of Japan and Philippines contain Triassic mid-oceanic seamount carbonates from the western Panthalassa Ocean (Onoue & Sano, 2007; Kiessling & Flügel, 2000). They have been accreted either as isolated limestone slabs or as clasts and boulders, and are associated with mudstones, cherts, breccias and basaltic rocks. Two major tectonic units forming Hokkaido Island and containing Triassic limestones have been accurately explored and extensively sampled: the Oshima Belt (west Hokkaido) a Jurassic accretionary complex, and the Cretaceous Sorachi-Yezo Belt (central Hokkaido). The Sorachi-Yezo Belt is composed of Cretaceous accretionary complexes in the east and of Cretaceous clastic basin sediments deposited on a Jurassic basement in the west (Ueda, 2016), both containing Triassic limestones. The origin of this belt is still matter of debate especially because of its western part which is not in continuity with any other accretionary complex known in the other islands of Japan and also due to the lack of data in this region. One of the main goals of this study is to

Kinetic Hydration Heat Modeling for High-Performance Concrete Containing Limestone Powder

Directory of Open Access Journals (Sweden)

Xiao-Yong Wang

2017-01-01

Full Text Available Limestone powder is increasingly used in producing high-performance concrete in the modern concrete industry. Limestone powder blended concrete has many advantages, such as increasing the early-age strength, reducing the setting time, improving the workability, and reducing the heat of hydration. This study presents a kinetic model for modeling the hydration heat of limestone blended concrete. First, an improved hydration model is proposed which considers the dilution effect and nucleation effect due to limestone powder addition. A degree of hydration is calculated using this improved hydration model. Second, hydration heat is calculated using the degree of hydration. The effects of water to binder ratio and limestone replacement ratio on hydration heat are clarified. Third, the temperature history and temperature distribution of hardening limestone blended concrete are calculated by combining hydration model with finite element method. The analysis results generally agree with experimental results of high-performance concrete with various mixing proportions.

SLAM: a sodium-limestone concrete ablation model

International Nuclear Information System (INIS)

Suo-Anttila, A.J.

1983-12-01

SLAM is a three-region model, containing a pool (sodium and reaction debris) region, a dry (boundary layer and dehydrated concrete) region, and a wet (hydrated concrete) region. The model includes a solution to the mass, momentum, and energy equations in each region. A chemical kinetics model is included to provide heat sources due to chemical reactions between the sodium and the concrete. Both isolated model as well as integrated whole code evaluations have been made with good results. The chemical kinetics and water migration models were evaluated separately, with good results. Several small and large-scale sodium limestone concrete experiments were simulated with reasonable agreement between SLAM and the experimental results. The SLAM code was applied to investigate the effects of mixing, pool temperature, pool depth and fluidization. All these phenomena were found to be of significance in the predicted response of the sodium concrete interaction. Pool fluidization is predicted to be the most important variable in large scale interactions

Attrition of limestone by impact loading in fluidized beds

Energy Technology Data Exchange (ETDEWEB)

Fabrizio Scala; Fabio Montagnaro; Piero Salatino [Consiglio Nazionale delle Ricerche, Napoli (Italy). Istituto di Ricerche sulla Combustione

2007-09-15

The present study addresses limestone attrition and fragmentation associated with impact loading, a process which may occur extensively in various regions of fluidized bed (FB) combustors/gasifiers, primarily the jetting region of the bottom bed, the exit region of the riser, and the cyclone. An experimental protocol for the characterization of the propensity of limestone to undergo attrition/fragmentation by impact loading is reported. The application of the protocol is demonstrated with reference to an Italian limestone whose primary fragmentation and attrition by surface wear have already been characterized in previous studies. The experimental procedure is based on the characterization of the amount and particle size distribution of the debris generated upon the impact of samples of sorbent particles against a target. Experiments were carried out at a range of particle impact velocities between 10 and 45 m/s, consistent with jet velocities corresponding to typical pressure drops across FB gas distributors. The protocol has been applied to either raw or preprocessed limestone samples. In particular, the effect of calcination, sulfation, and calcination/recarbonation cycles on the impact damage suffered by sorbent particles has been assessed. The measurement of particle voidage and pore size distribution by mercury intrusion was also accomplished to correlate fragmentation with the structural properties of the sorbent samples. Fragmentation by impact loading of the limestone is significant. Lime displays the largest propensity to undergo impact damage, followed by the sorbent sulfated to exhaustion, the recarbonated sorbent, and the raw limestone. Fragmentation of the raw limestone and of the sulfated lime follows a pattern typical of the failure of brittle materials. The fragmentation behavior of lime and recarbonated lime better conforms to a disintegration failure mode, with an extensive generation of very fine fragments. 27 refs., 9 figs. 1 tab.

CALCIUM OXIDE CHARACTERISTICS PREPARED FROM AMBUNTEN’S CALCINED LIMESTONE

Directory of Open Access Journals (Sweden)

Fatimatul Munawaroh

2018-05-01

Full Text Available Calcium oxide (CaO and calcium carbonate (CaCO3 are widely used in industry. CaO and CaCO3 can be synthesized or derived from limestone. The purpose of this study to determine the characteristics of CaO calcined limestone from Ambunten Sumenep. Lime in calcined at 850 ° C for 6 hours. Characterization of X-ray fluorescence (XRF was conducted to determine the chemical composition of limestone, X-ray diffraction test (XRD to find the lime crystalline phase and FTIR test to determine the absorption of wave number. XRF test results showed that the limestone chemical composition consisted of Ca of 95.37% as the dominant element, Mg of 4.1%, Fe 0.17% and Y by 0.39%. The XRD test results showed that the limestone crystal phase is ankerite (Ca [Fe, Mg] [CO3] 2 and after the calcined phase calcination is vaterite (Ca [OH] 2, calcite (CaO and calcite (CaCO3. While the FTIR test results show that the CaO spectra are seen at 3741.24, 1417.12 and 874.14 cm-1.

Accurate approximation method for prediction of class I MHC affinities for peptides of length 8, 10 and 11 using prediction tools trained on 9mers

DEFF Research Database (Denmark)

Lundegaard, Claus; Lund, Ole; Nielsen, Morten

2008-01-01

Several accurate prediction systems have been developed for prediction of class I major histocompatibility complex (MHC):peptide binding. Most of these are trained on binding affinity data of primarily 9mer peptides. Here, we show how prediction methods trained on 9mer data can be used for accurate...

Heart rate during basketball game play and volleyball drills accurately predicts oxygen uptake and energy expenditure.

Science.gov (United States)

Scribbans, T D; Berg, K; Narazaki, K; Janssen, I; Gurd, B J

2015-09-01

There is currently little information regarding the ability of metabolic prediction equations to accurately predict oxygen uptake and exercise intensity from heart rate (HR) during intermittent sport. The purpose of the present study was to develop and, cross-validate equations appropriate for accurately predicting oxygen cost (VO2) and energy expenditure from HR during intermittent sport participation. Eleven healthy adult males (19.9±1.1yrs) were recruited to establish the relationship between %VO2peak and %HRmax during low-intensity steady state endurance (END), moderate-intensity interval (MOD) and high intensity-interval exercise (HI), as performed on a cycle ergometer. Three equations (END, MOD, and HI) for predicting %VO2peak based on %HRmax were developed. HR and VO2 were directly measured during basketball games (6 male, 20.8±1.0 yrs; 6 female, 20.0±1.3yrs) and volleyball drills (12 female; 20.8±1.0yrs). Comparisons were made between measured and predicted VO2 and energy expenditure using the 3 equations developed and 2 previously published equations. The END and MOD equations accurately predicted VO2 and energy expenditure, while the HI equation underestimated, and the previously published equations systematically overestimated VO2 and energy expenditure. Intermittent sport VO2 and energy expenditure can be accurately predicted from heart rate data using either the END (%VO2peak=%HRmax x 1.008-17.17) or MOD (%VO2peak=%HRmax x 1.2-32) equations. These 2 simple equations provide an accessible and cost-effective method for accurate estimation of exercise intensity and energy expenditure during intermittent sport.

Identifying parameter windows for sulfur removal by direct limestone injection in the rich zone of staged heat engine combustors

International Nuclear Information System (INIS)

Colaluca, M.A.

1990-01-01

Recent experimental evidence suggests the possibility of sulfur cleanup by direct injection at gas temperatures that do not thermodynamically favor the absorption of sulfur by the limestone. The purpose of this paper is to analytically investigate possible mechanistic explanations of this observed sulfur capture with the goal of evaluating the potential for limestone injection sulfur capture in direct coal fired gas turbine and diesel engine (heat engines) combustion applications. The method was to use current available data on the physical properties of limestone, and the rates of the pertinent reactions, and to develop mathematical models of the processes experienced by the sorbent particles. The models were then used to predict extent of capture at the high-pressure, high-temperature, short residence time conditions of interest. The goal was to first investigate capture in a single-pulse reactor (combustion bomb) and then to extrapolate these results to advanced coal-fired heat engine combustion environments. Model predictions were in good agreement with observed sulfur capture in cold wall combustion bomb studies and suggest that efficient sulfur capture (in excess of 80 percent calcium utilization) may b e possible when limestone sorbents are injected into high-temperature combustion products, even when the gas temperatures exceed the thermodynamically favored temperature window by several hundred kelvins. This behavior is possible because particle temperatures are moderated and held at levels that favor sulfur capture due to the strongly endothermic calcination reaction

Limestone doses affecting mineral contents in tropical grass forage

International Nuclear Information System (INIS)

Armelin, M.J.A.; Saiki, M.

2005-01-01

Field trial was performed at the experimental farm of Southeast Embrapa Cattle, Sao Carlos - SP, Brazil, on a 16 year old Brachiaria decumbens pasture, grown on a distrophic Hapludox (Oxisol), recovered by the use of limestone and fertilizer. The experiments were carried out in random blocks, with 6 replications and 5 treatments. The 100 m 2 blocks were established in the pasture. Each block received a sequence of limestone doses of 0, 1, 2, 4 and 8 t/ha. The forage samples were taken one year after limestone application on soil surface. Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was the analytical method used to determine mineral contents. The statistical analysis showed a negative linear correlation of Br, Co, Cr, Mn and Zn contents in forage with the limestone doses, while the uptake of Mg was affected in a positive way. (author)

PredictSNP: robust and accurate consensus classifier for prediction of disease-related mutations.

Directory of Open Access Journals (Sweden)

Jaroslav Bendl

2014-01-01

Full Text Available Single nucleotide variants represent a prevalent form of genetic variation. Mutations in the coding regions are frequently associated with the development of various genetic diseases. Computational tools for the prediction of the effects of mutations on protein function are very important for analysis of single nucleotide variants and their prioritization for experimental characterization. Many computational tools are already widely employed for this purpose. Unfortunately, their comparison and further improvement is hindered by large overlaps between the training datasets and benchmark datasets, which lead to biased and overly optimistic reported performances. In this study, we have constructed three independent datasets by removing all duplicities, inconsistencies and mutations previously used in the training of evaluated tools. The benchmark dataset containing over 43,000 mutations was employed for the unbiased evaluation of eight established prediction tools: MAPP, nsSNPAnalyzer, PANTHER, PhD-SNP, PolyPhen-1, PolyPhen-2, SIFT and SNAP. The six best performing tools were combined into a consensus classifier PredictSNP, resulting into significantly improved prediction performance, and at the same time returned results for all mutations, confirming that consensus prediction represents an accurate and robust alternative to the predictions delivered by individual tools. A user-friendly web interface enables easy access to all eight prediction tools, the consensus classifier PredictSNP and annotations from the Protein Mutant Database and the UniProt database. The web server and the datasets are freely available to the academic community at http://loschmidt.chemi.muni.cz/predictsnp.

LUTETIAN LIMESTONES IN THE PARIS REGION: PETROGRAPHIC AND COMPOSITIONAL EXAMINATION

International Nuclear Information System (INIS)

BLANC, A.; HOLMES, L.L.; HARBOTTLE, G.

1998-01-01

Stone for building and decorating monuments in the Paris Basin from antiquity to the present came from numerous quarries in the Lutetian limestone formations of the region. To identify specific-stone sources used for masonry and sculptures in these monuments, a team of geologists and archaeologists has investigated 300 quarries and collected 2,300 limestone samples for study in a collaborative effort by geologists and chemists. Petrographic and paleontologic examinations of thin sections enable geologists to distinguish the Tertiary Lutetian limestones from similar stone in Jurassic and Cretaceous strata. The methods of the geologist have been supplemented by those of the chemist whose compositional studies by neutron activation analysis can differentiate among the fine-grained upper Lutetian limestones extracted from specific ancient quarries

Characterization of Limestone as Raw Material to Hydrated Lime

Science.gov (United States)

Salem Hwidi, Rajeb; Nuraiti Tengku Izhar, Tengku; Saad, Farah Naemah Mohd

2018-03-01

In Malaysia, limestone is essentially important for the economic growth as raw materials in the industry sector. Nevertheless, a little attention was paid to the physical, chemical, mineralogical, and morphological properties of the limestone using X-ray fluorescence (X-RF), X-ray diffraction (X-RD), Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy / energy dispersive x-ray spectroscopy (SEM-EDS) respectively. Raw materials (limestone rocks) were collected from Bukit Keteri area, Chuping, Kangar, Perlis, Malaysia. Lab crusher and lab sieved were utilized to prepare five different size of ground limestone at (75 µm, 150 µm, 225 µm, 300, and 425 µm) respectively. It is found that the main chemical composition of bulk limestone was Calcium oxide (CaO) at 97.58 wt.% and trace amount of MnO, Al2O3, and Fe2O3 at 0.02%, 0.35%, and 0.396% respectively. XRD diffractograms showed characteristic peaks of calcite and quartz. Furthermore, main FTIR absorption bands at 1,419, 874.08 and 712.20 cm-1 indicated the presence of calcite. The micrographs showed clearly the difference of samples particle size. Furthermore, EDS peaks of Ca, O, and C elements confirmed the presence of CaCO3 in the samples.

Oxic limestone drains for treatment of dilute, acidic mine drainage

Science.gov (United States)

Cravotta, Charles A.

1998-01-01

Limestone treatment systems can be effective for remediation of acidic mine drainage (AMD) that contains moderate concentrations of dissolved O2 , Fe3+ , or A13+ (1‐5 mg‐L‐1 ). Samples of water and limestone were collected periodically for 1 year at inflow, outflow, and intermediate points within underground, oxic limestone drains (OLDs) in Pennsylvania to evaluate the transport of dissolved metals and the effect of pH and Fe‐ and Al‐hydrolysis products on the rate of limestone dissolution. The influent was acidic and relatively dilute (pH 1 mg‐L‐1 ) but was near neutral (pH = 6.2‐7.0); Fe and Al decreased to less than 5% of influent concentrations. As pH increased near the inflow, hydrous Fe and Al oxides precipitated in the OLDs. The hydrous oxides, nominally Fe(OH)3 and AI(OH)3, were visible as loosely bound, orange‐yellow coatings on limestone near the inflow. As time elapsed, Fe(OH)3 and AI(OH)3 particles were transported downflow. During the first 6 months of the experiment, Mn 2+ was transported conservatively through the OLDs; however, during the second 6 months, concentrations of Mn in effluent decreased by about 50% relative to influent. The accumulation of hydrous oxides and elevated pH (>5) in the downflow part of the OLDs promoted sorption and coprecipitation of Mn as indicated by its enrichment relative to Fe in hydrous‐oxide particles and coatings on limestone. Despite thick (~1 mm) hydrous‐oxide coatings on limestone near the inflow, CaCO3 dissolution was more rapid near the inflow than at downflow points within the OLD where the limestone was not coated. The rate of limestone dissolution decreased with increased residence time, pH, and concentrations of Ca2+ and HCO3‐ and decreased PCO2. The following overall reaction shows alkalinity as an ultimate product of the iron hydrolysis reaction in an OLD:Fe2+ + 0.25 O2 +CaCO3 + 2.5 H2O --> Fe(OH)3 + 2 Ca2+ + 2 HCO3-where 2 moles of CaCO3 dissolve for each mole of Fe(OH)3 produced

Catalytic and Gas-Solid Reactions Involving HCN over Limestone

DEFF Research Database (Denmark)

Jensen, Anker; Johnsson, Jan Erik; Dam-Johansen, Kim

1997-01-01

In coal-fired combustion systems solid calcium species may be present as ash components or limestone added to the combustion chamber. In this study heterogeneous reactions involving HCN over seven different limestones were investigated in a laboratory fixed-bed quartz reactor at 873-1,173 K...

A new, accurate predictive model for incident hypertension.

Science.gov (United States)

Völzke, Henry; Fung, Glenn; Ittermann, Till; Yu, Shipeng; Baumeister, Sebastian E; Dörr, Marcus; Lieb, Wolfgang; Völker, Uwe; Linneberg, Allan; Jørgensen, Torben; Felix, Stephan B; Rettig, Rainer; Rao, Bharat; Kroemer, Heyo K

2013-11-01

Data mining represents an alternative approach to identify new predictors of multifactorial diseases. This work aimed at building an accurate predictive model for incident hypertension using data mining procedures. The primary study population consisted of 1605 normotensive individuals aged 20-79 years with 5-year follow-up from the population-based study, that is the Study of Health in Pomerania (SHIP). The initial set was randomly split into a training and a testing set. We used a probabilistic graphical model applying a Bayesian network to create a predictive model for incident hypertension and compared the predictive performance with the established Framingham risk score for hypertension. Finally, the model was validated in 2887 participants from INTER99, a Danish community-based intervention study. In the training set of SHIP data, the Bayesian network used a small subset of relevant baseline features including age, mean arterial pressure, rs16998073, serum glucose and urinary albumin concentrations. Furthermore, we detected relevant interactions between age and serum glucose as well as between rs16998073 and urinary albumin concentrations [area under the receiver operating characteristic (AUC 0.76)]. The model was confirmed in the SHIP validation set (AUC 0.78) and externally replicated in INTER99 (AUC 0.77). Compared to the established Framingham risk score for hypertension, the predictive performance of the new model was similar in the SHIP validation set and moderately better in INTER99. Data mining procedures identified a predictive model for incident hypertension, which included innovative and easy-to-measure variables. The findings promise great applicability in screening settings and clinical practice.

Limestone quarrying and quarry reclamation in Britain

Science.gov (United States)

Gunn, J.; Bailey, D.

1993-06-01

Limestones have been worked for many thousands of years — initially for building stone and agricultural lime and more recently for a wide range of construction and industrial uses. In most industrialized countries limestone quarries represent the most visually obvious and, in both process and landform terms, the most dramatic anthropogenic impact on karst terrain. However, quarrying has, to date, received surprisingly little attention from karst scientists. Research in the English Peak District suggested that the postexcavation evolution of quarried limestone rock faces was in part a result of the methods used in their excavation, and this led to the development of a technique designed to reduce the visual and environmental impacts of modern quarries by “Landform replication. ” This involves the use of controlled “restoration blasting” techniques on quarried rock slopes to construct a landform sequence similar to that in the surrounding natural landscape. The constructed landforms are then partially revegetated using appropriate wildflower, grass, and/or tree species.

Simultaneous removal of several heavy metals from aqueous solution by natural limestones

Directory of Open Access Journals (Sweden)

Sdiri A.

2014-07-01

Full Text Available Four natural limestone samples, collected from the Campanian-Maastrichtian limestones, Tunisia, were used as adsorbents for the removal of toxic metals in aqueous systems. The results indicated that high removal efficiency could be achieved by the present natural limestones. Among the metal ions studied, Pb2+ was the most preferably removed cation because of its high affinity to calcite surface. In binary system, the presence of Cu2+ effectively depressed the sorption of Cd2+ and Zn2+. Similarly Cu2+ strongly competed with Pb2+ to limestone surface. In ternary system, the removal further decreased, but considerable amount of Pb2+ and Cu2+ still occurred regardless of the limestone sample. The same behavior was observed in quadruple system, where the selectivity sequence was Pb2+ > Cu2+ > Cd2+ > Zn2+. From these results, it was concluded that the studied limestones have the required technical specifications to be used for the removal of toxic metals from wastewaters.

The use of Limestone Powder as an Alternative Cement Replacement

African Journals Online (AJOL)

user

focused on the effects of limestone on the cement ... construction materials in Ethiopia is increasing .... Findings of research works on the strength reveals ... This CEN standard sand is delivered ... control mix made without limestone fines.

Drenov Grič black limestone as a heritage stone from Slovenia

Science.gov (United States)

Kramar, Sabina; Rožič, Boštjan; Žbona, Nina; Bedjanič, Mojca; Mladenović, Ana

2016-04-01

The limestone known as Drenov Grič black limestone is considered one of the most beautiful Slovenian natural stones due to its homogenous black colour interwoven with white veins. Over the centuries it has been exploited from three major quarries west of Ljubljana, with the main quarry at Drenov Grič playing the primary role in supplying building material for the central parts of Slovenia. All the quarries are currently not active. In the area of Drenov grič, one locality of black limestone is protected - Kuclerjev kamnolom quarry. It has the status of 'valuable natural feature of national importance' and is protected as a natural monument. This well-stratified micritic limestone of Triassic (Carnian) age occurs in 10-80 cm thick beds, with thin marl interlayers. The stone contains abundant fossil bivalves and ostracods. Apart from calcite as the main component, dolomite, quartz, illite/muscovite and pyrite are also present. The limestone is relatively rich in carbonaceous and bituminous organic matter, which is responsible for the black colour of the stone. This component does not have any adverse effect on mechanical and physical characteristics. As the lime¬stone is dense, thus facilitating a good polish, it has been commercially considered as marble. The stone has been widely used in Slovenian monuments, not only in Ljubljana but also in other regions of Slovenia. Many inner and outdoor architectural elements were made of this limestone, particularly in the baroque period, which was known for the extensive use of black limestones also in other European countries. The most significant use of this limestone has been recorded in sculptured portals and altars. Some of the important buildings decorated utilising this stone, are the Ljubljana Cathedral, the St. James's Parish Church, and the Franciscan Church of the Annunciation, all of which are located in Ljubljana, some of them having been declared as cultural monuments of local or national importance. When

Steam Cured Self-Consolidating Concrete and the Effects of Limestone Filler

Science.gov (United States)

Aqel, Mohammad A.

The purpose of this thesis is to determine the effect and the mechanisms associated with replacing 15% of the cement by limestone filler on the mechanical properties and durability performance of self-consolidating concrete designed and cured for precast/prestressed applications. This study investigates the role of limestone filler on the hydration kinetics, mechanical properties (12 hours to 300 days), microstructural and durability performance (rapid chloride permeability, linear shrinkage, sulfate resistance, freeze-thaw resistance and salt scaling resistance) of various self-consolidating concrete mix designs containing 5% silica fume and steam cured at a maximum holding temperature of 55°C. This research also examines the resistance to delayed ettringite formation when the concrete is steam cured at 70°C and 82°C and its secondary consequences on the freeze-thaw resistance. The effect of several experimental variables related to the concrete mix design and also the curing conditions are examined, namely: limestone filler fineness, limestone filler content, cement type, steam curing duration and steam curing temperature. In general, the results reveal that self-consolidating concrete containing 15% limestone filler, steam cured at 55°C, 70°C and 82°C, exhibited similar or superior mechanical and transport properties as well as long term durability performance compared to similar concrete without limestone filler. When the concrete is steam cured at 55°C, the chemical reactivity of limestone filler has an important role in enhancing the mechanical properties at 16 hours (compared to the concrete without limestone filler) and compensating for the dilution effect at 28 days. Although, at 300 days, the expansion of all concrete mixes are below 0.05%, the corresponding freeze-thaw durability factors vary widely and are controlled by the steam curing temperature and the chemical composition of the cement. Overall, the material properties indicate that the use

Additional Gigantoproductus species from the upper Visean-Namurian limestone of Kotaki, central Japan

OpenAIRE

Ibaraki, Yousuke; Tazawa, Jun-ichi; Nakamura, Yukio

2010-01-01

A large productid brachiopod species, Gigantoproductus aurita (Bolkhovitinova, 1938), is described from the Tsuchikurazawa Limestone (upper Visean-Namurian), a large limestone block within a Permian accretionary complex of Kotaki, Itoigawa City, Niigata Prefecture, central Japan. This is the fourth described Gigantoproductus species from the Tsuchikurazawa Limestone. The range of G. aurita may extend to late Visean on the basis of the previous fossil records of the limestone.

Hydration mechanisms of ternary Portland cements containing limestone powder and fly ash

International Nuclear Information System (INIS)

De Weerdt, K.; Haha, M. Ben; Le Saout, G.; Kjellsen, K.O.; Justnes, H.; Lothenbach, B.

2011-01-01

The effect of minor additions of limestone powder on the properties of fly ash blended cements was investigated in this study using isothermal calorimetry, thermogravimetry (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) techniques, and pore solution analysis. The presence of limestone powder led to the formation of hemi- and monocarbonate and to a stabilisation of ettringite compared to the limestone-free cements, where a part of the ettringite converted to monosulphate. Thus, the presence of 5% of limestone led to an increase of the volume of the hydrates, as visible in the increase in chemical shrinkage, and an increase in compressive strength. This effect was amplified for the fly ash/limestone blended cements due to the additional alumina provided by the fly ash reaction.

Geochemistry, environmental and provenance study of the Middle Miocene Leitha limestones (Central Paratethys

Directory of Open Access Journals (Sweden)

Ali Ahmed

2017-06-01

Full Text Available Mineralogical, major, minor, REE and trace element analyses of rock samples were performed on Middle Miocene limestones (Leitha limestones, Badenian collected from four localities from Austria (Mannersdorf, Wöllersdorf, Kummer and Rosenberg quarries and the Fertőrákos quarry in Hungary. Impure to pure limestones (i.e. limited by Al2O3 contents above or below 0.43 wt. % were tested to evaluate the applicability of various geochemical proxies and indices in regard to provenance and palaeoenvironmental interpretations. Pure and impure limestones from Mannersdorf and Wöllersdorf (southern Vienna Basin show signs of detrital input (REEs = 27.6 ± 9.8 ppm, Ce anomaly = 0.95 ± 0.1 and the presence of quartz, muscovite and clay minerals in impure limestones and diagenetic influence (low contents of, e.g., Sr = 221 ± 49 ppm, Na is not detected, Ba = 15.6 ± 8.8 ppm in pure limestones. Thus, in both limestones the reconstruction of original sedimentary palaeoenvironments by geochemistry is hampered. The Kummer and Fertőrákos (Eisenstadt–Sopron Basin comprise pure limestones (e.g., averages Sr = 571 ± 139 ppm, Na = 213 ± 56 ppm, Ba = 21 ± 4 ppm, REEs = 16 ± 3 ppm and Ce anomaly = 0.62 ± 0.05 and composed predominantly of calcite exhibiting negligible diagenesis. Deposition under a shallow-water, well oxygenated to intermittent dysoxic marine environment can be reconstructed. Pure to impure limestones at Rosenberg–Retznei (Styrian Basin are affected to some extent by detrital input and volcano-siliciclastic admixture. The Leitha limestones at Rosenberg have the least diagenetic influence among the studied localities (i.e. averages Sr = 1271 ± 261 ppm, Na = 315 ± 195 ppm, Ba = 32 ± 15 ppm, REEs = 9.8 ± 4.2 ppm and Ce anomaly = 0.77 ± 0.1 and consist of calcite, minor dolomite and quartz. The siliciclastic sources are characterized by immobile elemental ratios (i.e. La/Sc and Th/Co which apply not only for the siliciclastics, but also

Geochemistry, environmental and provenance study of the Middle Miocene Leitha limestones (Central Paratethys)

Science.gov (United States)

Ali, Ahmed; Wagreich, Michael

2017-06-01

Mineralogical, major, minor, REE and trace element analyses of rock samples were performed on Middle Miocene limestones (Leitha limestones, Badenian) collected from four localities from Austria (Mannersdorf, Wöllersdorf, Kummer and Rosenberg quarries) and the Fertőrákos quarry in Hungary. Impure to pure limestones (i.e. limited by Al2O3 contents above or below 0.43 wt. %) were tested to evaluate the applicability of various geochemical proxies and indices in regard to provenance and palaeoenvironmental interpretations. Pure and impure limestones from Mannersdorf and Wöllersdorf (southern Vienna Basin) show signs of detrital input (REEs = 27.6 ± 9.8 ppm, Ce anomaly = 0.95 ± 0.1 and the presence of quartz, muscovite and clay minerals in impure limestones) and diagenetic influence (low contents of, e.g., Sr = 221 ± 49 ppm, Na is not detected, Ba = 15.6 ± 8.8 ppm in pure limestones). Thus, in both limestones the reconstruction of original sedimentary palaeoenvironments by geochemistry is hampered. The Kummer and Fertőrákos (Eisenstadt-Sopron Basin) comprise pure limestones (e.g., averages Sr = 571 ± 139 ppm, Na = 213 ± 56 ppm, Ba = 21 ± 4 ppm, REEs = 16 ± 3 ppm and Ce anomaly = 0.62 ± 0.05 and composed predominantly of calcite) exhibiting negligible diagenesis. Deposition under a shallow-water, well oxygenated to intermittent dysoxic marine environment can be reconstructed. Pure to impure limestones at Rosenberg-Retznei (Styrian Basin) are affected to some extent by detrital input and volcano-siliciclastic admixture. The Leitha limestones at Rosenberg have the least diagenetic influence among the studied localities (i.e. averages Sr = 1271 ± 261 ppm, Na = 315 ± 195 ppm, Ba = 32 ± 15 ppm, REEs = 9.8 ± 4.2 ppm and Ce anomaly = 0.77 ± 0.1 and consist of calcite, minor dolomite and quartz). The siliciclastic sources are characterized by immobile elemental ratios (i.e. La/Sc and Th/Co) which apply not only for the siliciclastics, but also for marls and

Kinetic Study of Calcination of Jakura Limestone Using Power Rate ...

African Journals Online (AJOL)

National Research Institute for Chemical Technology, P.M. B 1052, Zaria, ... calcination of Jakura limestone was also found to be first order reaction with respect to CaCO3 ... Keywords: Jakura, limestone, calcination, kinetics, power law model.

Studies on the preparation of value-added products for limestone

Energy Technology Data Exchange (ETDEWEB)

Chae, Young Bae; Jeong, Soo Bok; Ko, Won Sik; Park, Je Shin; Oh, Jung Whan [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

1997-12-01

Most of limestone in our country was consumed by the cement and iron/steel making industries and the amount of that was up to 72 million ton in 1996. Recently, importation of high grade limestone that have properties of high whiteness and grade are increased with diversification of chemical products and powder as various qualified filler, because high grade limestone are limited and of few deposit in our country. Therefore, the purpose of this study has investigated to raise to high grade by economical processes with low grade of domestic limestone. In this year, first of all, we investigated the status of application utilize and related industries with the domestic limestone, and then being consideration with condition selected the adequate sample from Andong, Jungsun and Kumsan area. Magnetic materials were involved in impurities of sample, so magnetic separation method was applied in elimination of the ferro-magnetic materials and para-magnetic materials, such as chlorite, muscovite, quartz, dolomite, magnetite, feldspar and so on. The limestone sample has many kinds of impurity. Investigation of flotation was undertaken to eliminate impurities from limestone crude ore and the tests were performed to get a optimum condition adding oleic acid as a promoter, sodium silicate and sodium carbonate as a conditioning agents and MIBC as a frother, while to float the sulfide minerals added amyl xanthate as a promoter, and sulfuric acid as a pH regulator. And most of the impurities involving in flotation sink contained such as quartz, chlorite, muscovite, feldspar, dolomite and so on. Selective crushing and classification methods were performed to eliminate impurities depends on the mineral properties and should be the selective crushing methods are very useful at the manufacturing factory of heavy calcium carbonate with the dry milling system. (author). 36 refs., 46 tabs., 33 figs.

Modifying the properties of finely ground limestone by tumbling granulation

Science.gov (United States)

Macho, Oliver; Eckert, Maroš; Tomášová, Barbora; Peciar, Peter; Ščasný, Martin; Fekete, Roman; Peciar, Marián

2016-06-01

Calcium carbonate in the form of finely ground limestone is a material that has found its application in a wide range of industries, in the chemical, rubber, agricultural, and paper industries, is used for desulfurization of boilers and other. In civil engineering, ground limestone is used for the production of building materials, plaster and mortar mixtures, as a filler in concrete mixtures, in road construction, and as an essential component of mastic asphalt. This paper deals with examining the modification of the properties of finely ground limestone by the tumbling agglomeration method. It has been shown that the components of concrete with a round grain have a positive effect on the pumping of concrete in comparison with an elongated grain or the rough surface of crushed stone. The experiments will be carried out on a granulation plate using a variety of granulation liquid. The agglomerates and their properties were compared with untreated finely ground limestone, with a focus on detecting changes in compressibility, density and particle size. The output of this paper is a description and graphical representation of the changes in the properties of ground limestone before and after the agglomeration process.

Modifying the properties of finely ground limestone by tumbling granulation

Directory of Open Access Journals (Sweden)

Macho Oliver

2016-06-01

Full Text Available Calcium carbonate in the form of finely ground limestone is a material that has found its application in a wide range of industries, in the chemical, rubber, agricultural, and paper industries, is used for desulfurization of boilers and other. In civil engineering, ground limestone is used for the production of building materials, plaster and mortar mixtures, as a filler in concrete mixtures, in road construction, and as an essential component of mastic asphalt. This paper deals with examining the modification of the properties of finely ground limestone by the tumbling agglomeration method. It has been shown that the components of concrete with a round grain have a positive effect on the pumping of concrete in comparison with an elongated grain or the rough surface of crushed stone. The experiments will be carried out on a granulation plate using a variety of granulation liquid. The agglomerates and their properties were compared with untreated finely ground limestone, with a focus on detecting changes in compressibility, density and particle size. The output of this paper is a description and graphical representation of the changes in the properties of ground limestone before and after the agglomeration process.

An Overview of Practical Applications of Protein Disorder Prediction and Drive for Faster, More Accurate Predictions.

Science.gov (United States)

Deng, Xin; Gumm, Jordan; Karki, Suman; Eickholt, Jesse; Cheng, Jianlin

2015-07-07

Protein disordered regions are segments of a protein chain that do not adopt a stable structure. Thus far, a variety of protein disorder prediction methods have been developed and have been widely used, not only in traditional bioinformatics domains, including protein structure prediction, protein structure determination and function annotation, but also in many other biomedical fields. The relationship between intrinsically-disordered proteins and some human diseases has played a significant role in disorder prediction in disease identification and epidemiological investigations. Disordered proteins can also serve as potential targets for drug discovery with an emphasis on the disordered-to-ordered transition in the disordered binding regions, and this has led to substantial research in drug discovery or design based on protein disordered region prediction. Furthermore, protein disorder prediction has also been applied to healthcare by predicting the disease risk of mutations in patients and studying the mechanistic basis of diseases. As the applications of disorder prediction increase, so too does the need to make quick and accurate predictions. To fill this need, we also present a new approach to predict protein residue disorder using wide sequence windows that is applicable on the genomic scale.

An Overview of Practical Applications of Protein Disorder Prediction and Drive for Faster, More Accurate Predictions

Directory of Open Access Journals (Sweden)

Xin Deng

2015-07-01

Full Text Available Protein disordered regions are segments of a protein chain that do not adopt a stable structure. Thus far, a variety of protein disorder prediction methods have been developed and have been widely used, not only in traditional bioinformatics domains, including protein structure prediction, protein structure determination and function annotation, but also in many other biomedical fields. The relationship between intrinsically-disordered proteins and some human diseases has played a significant role in disorder prediction in disease identification and epidemiological investigations. Disordered proteins can also serve as potential targets for drug discovery with an emphasis on the disordered-to-ordered transition in the disordered binding regions, and this has led to substantial research in drug discovery or design based on protein disordered region prediction. Furthermore, protein disorder prediction has also been applied to healthcare by predicting the disease risk of mutations in patients and studying the mechanistic basis of diseases. As the applications of disorder prediction increase, so too does the need to make quick and accurate predictions. To fill this need, we also present a new approach to predict protein residue disorder using wide sequence windows that is applicable on the genomic scale.

STEAM INJECTION INTO FRACTURED LIMESTONE AT LORING AIR FORCE BASE

Science.gov (United States)

A research project on steam injection for the remediation of spent chlorinated solvents from fractured limestone was recently undertaken at the former Loring AFB in Limestone, ME. Participants in the project include the Maine Department of Environmental Protection, EPA Region I,...

Multi-fidelity machine learning models for accurate bandgap predictions of solids

International Nuclear Information System (INIS)

Pilania, Ghanshyam; Gubernatis, James E.; Lookman, Turab

2016-01-01

Here, we present a multi-fidelity co-kriging statistical learning framework that combines variable-fidelity quantum mechanical calculations of bandgaps to generate a machine-learned model that enables low-cost accurate predictions of the bandgaps at the highest fidelity level. Additionally, the adopted Gaussian process regression formulation allows us to predict the underlying uncertainties as a measure of our confidence in the predictions. In using a set of 600 elpasolite compounds as an example dataset and using semi-local and hybrid exchange correlation functionals within density functional theory as two levels of fidelities, we demonstrate the excellent learning performance of the method against actual high fidelity quantum mechanical calculations of the bandgaps. The presented statistical learning method is not restricted to bandgaps or electronic structure methods and extends the utility of high throughput property predictions in a significant way.

Rapid and accurate prediction and scoring of water molecules in protein binding sites.

Directory of Open Access Journals (Sweden)

Gregory A Ross

Full Text Available Water plays a critical role in ligand-protein interactions. However, it is still challenging to predict accurately not only where water molecules prefer to bind, but also which of those water molecules might be displaceable. The latter is often seen as a route to optimizing affinity of potential drug candidates. Using a protocol we call WaterDock, we show that the freely available AutoDock Vina tool can be used to predict accurately the binding sites of water molecules. WaterDock was validated using data from X-ray crystallography, neutron diffraction and molecular dynamics simulations and correctly predicted 97% of the water molecules in the test set. In addition, we combined data-mining, heuristic and machine learning techniques to develop probabilistic water molecule classifiers. When applied to WaterDock predictions in the Astex Diverse Set of protein ligand complexes, we could identify whether a water molecule was conserved or displaced to an accuracy of 75%. A second model predicted whether water molecules were displaced by polar groups or by non-polar groups to an accuracy of 80%. These results should prove useful for anyone wishing to undertake rational design of new compounds where the displacement of water molecules is being considered as a route to improved affinity.

Resedimented Limestones in Middle and Upper Jurassic Succession of the Slovenian Basin

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Boštjan Rožič

2006-12-01

Full Text Available The Middle and Upper Jurassic succession of the Slovenian Basin is characterized by pelagic sedimentation of siliceous limestones and radiolarian cherts. In the southern and central part of the basin two packages of resedimented limestones are interbedded within pelagic sediments. The Lower resedimented limestones are lower-middle Bajocian to lower Callovian in age. In the southern part of the basin they form laterally discontinuous sequences composed of limestone breccias, calcarenites and micritic limestone and in the central part of the basin calcarenite intercalations within pelagic beds. They were transported by turbidity currents from highly productive ooidal shoals of the Dinaric Carbonate Platform. The Lower resedimented carbonates correlate with the lower three members of the Travnik Formation in the Bovec Trough and similarly developed but much thicker Vajont Formation in the Belluno Basin. The difference in thickness is interpreted as a consequence of shallow-water and longshore currents on the Dinaric Carbonate Platform that transported platform material towards southwest in the direction of the Belluno Basin. The Upper resedimented limestones are upper Kimmeridgian to lower Tithonian and occur within radiolarian cherts in the upper part of the succession as calcarenite beds that originated by turbidity currents. Onset of resedimentation coincides with the emersion-related demise of barrier reef and following deposition of micritic and rare oolitic limestones on the Dinaric Carbonate Platform. Approximatelly coeval resedimented limestones occur in the fourth member of the Travnik Formation in the Bovec Trough, but are not reported from the Ammonitico Rosso Superiore Formation in the Belluno Basin.

Coated limestone as a filler for the production of PVC-products

Directory of Open Access Journals (Sweden)

Mihajlović Slavica

2005-01-01

Full Text Available The results of laboratory investigations of the possibility to obtain coated limestone for the production of PVC-products are presented in this paper. Limestone from the "Venčac" deposit (Aranđelovac, Serbia and Montenegro was used as the raw material. The investigations were carried out in two phases: obtaining the coated limestone and determination of the degree of coating. The results of the investigations showed that successful coating of the surface of the limestone particles with Ca-stearate (Ca-stearate content 3% was achieved in a vibro mill with rings and the obtained degree of coating was higher than 95%. The coating degree was determined in transmitted light by a polarization microscope applying the immersion method (water immersion.

Differential contribution of visual and auditory information to accurately predict the direction and rotational motion of a visual stimulus.

Science.gov (United States)

Park, Seoung Hoon; Kim, Seonjin; Kwon, MinHyuk; Christou, Evangelos A

2016-03-01

Vision and auditory information are critical for perception and to enhance the ability of an individual to respond accurately to a stimulus. However, it is unknown whether visual and auditory information contribute differentially to identify the direction and rotational motion of the stimulus. The purpose of this study was to determine the ability of an individual to accurately predict the direction and rotational motion of the stimulus based on visual and auditory information. In this study, we recruited 9 expert table-tennis players and used table-tennis service as our experimental model. Participants watched recorded services with different levels of visual and auditory information. The goal was to anticipate the direction of the service (left or right) and the rotational motion of service (topspin, sidespin, or cut). We recorded their responses and quantified the following outcomes: (i) directional accuracy and (ii) rotational motion accuracy. The response accuracy was the accurate predictions relative to the total number of trials. The ability of the participants to predict the direction of the service accurately increased with additional visual information but not with auditory information. In contrast, the ability of the participants to predict the rotational motion of the service accurately increased with the addition of auditory information to visual information but not with additional visual information alone. In conclusion, this finding demonstrates that visual information enhances the ability of an individual to accurately predict the direction of the stimulus, whereas additional auditory information enhances the ability of an individual to accurately predict the rotational motion of stimulus.

Rare earth element and strontium isotopic study of seamount-type limestones in Mesozoic accretionary complex of Southern Chichibu Terrane, central Japan. Implication for incorporation process of seawater REE into limestones

International Nuclear Information System (INIS)

Tanaka, Kazuya; Miura, Noriko; Asahara, Yoshihiro; Kawabe, Iwao

2003-01-01

Ishimaki and Tahara limestones occur as exotic blocks juxtaposed in the Mesozoic (Jurassic) accretionary complex of Southern Chichibu Terrane in eastern Aichi Prefecture, central Japan. They are supposed to be of the seamount-type limestone, since they have no terrigenous materials and are intimately associated with greenstones. REE (rare earth elements) and Sr isotopic studies for the limestones have been made in order to know their geochemical characteristics, ages and origins. Their 87 Sr/ 86 Sr ratios, when referred to the seawater 87 Sr/ 86 Sr curve and relevant geological data, suggest that Ishimaki and Tahara limestones are the late Permian and the Carboniferous to the Early Permian, respectively. Two greenstone fragments found inside the Ishimaki limestone block and one greenstone sample associated with Tahara limestone block, resemble the Hawaiian alkali basalt in the their REE and Y patterns. This is supporting the idea that the limestone blocks may be parts of reef limestones on ancient volcanic seamounts. All the limestone samples, except three unusual Tahara ones, show seawater REE and Y signatures in their chondrite-normalized patterns. Their REE/Ca ratios, however, are 10 2 -10 4 times as high as those ratios of modern biogenic carbonates like corals and the seawater. Accordingly, seawater REE and Y were incorporated into the limestones, when originally biogenic carbonates transformed into inorganic calcite and its secondary growths occurred in diagenesis in contact with sufficient seawater. This view is favored by the reported REE partition experiment between calcite overgrowths and seawater solution. The seawater Ce anomaly as a function of water depth in the modern ocean is a key to infer the water depth of the REE and Y incorporation. The Ce anomalies given by log (Ce/Ce*) for about a half of Ishimaki samples and most of Tahara ones are between -0.5 and -0.2, which are compatible with the shallow water origin. Another half of Ishimaki samples

Initial kinetics of the direct sulfation of limestone

DEFF Research Database (Denmark)

Hu, Guilin; Shang, Lei; Dam-Johansen, Kim

2008-01-01

The initial kinetics of direct sulfation of Faxe Bryozo, a porous bryozoan limestone was studied in the temperature interval from 873 to 973 K in a pilot entrained flow reactor with very short reaction times (between 0.1 and 0.6 s). The initial conversion rate of the limestone - for conversions...... less than 0.3% - was observed to be significantly promoted by higher SO2 concentrations and lower CO2 concentrations, whereas 02 showed negligible influence. A mathematical model for the sulfation of limestone involving chemical reaction at calcite grain surfaces and solid-state diffusion of carbonate...... ions in calcite grains is established. The validity of the model is limited to the initial sulfation period, in which nucleation of the solid product calcium sulphate is not started. This theoretical reaction-diffusion model gives a good simulation of the initial kinetics of the direct sulfation...

Modeling of Hydration, Compressive Strength, and Carbonation of Portland-Limestone Cement (PLC Concrete

Directory of Open Access Journals (Sweden)

Xiao-Yong Wang

2017-01-01

Full Text Available Limestone is widely used in the construction industry to produce Portland limestone cement (PLC concrete. Systematic evaluations of hydration kinetics, compressive strength development, and carbonation resistance are crucial for the rational use of limestone. This study presents a hydration-based model for evaluating the influences of limestone on the strength and carbonation of concrete. First, the hydration model analyzes the dilution effect and the nucleation effect of limestone during the hydration of cement. The degree of cement hydration is calculated by considering concrete mixing proportions, binder properties, and curing conditions. Second, by using the gel–space ratio, the compressive strength of PLC concrete is evaluated. The interactions among water-to-binder ratio, limestone replacement ratio, and strength development are highlighted. Third, the carbonate material contents and porosity are calculated from the hydration model and are used as input parameters for the carbonation model. By considering concrete microstructures and environmental conditions, the carbon dioxide diffusivity and carbonation depth of PLC concrete are evaluated. The proposed model has been determined to be valid for concrete with various water-to-binder ratios, limestone contents, and curing periods.

Toxicity of acid mine pit lake water remediated with limestone and phosphorus

Energy Technology Data Exchange (ETDEWEB)

Neil, L.L.; McCullough, C.D.; Lund, M.A.; Evans, L.H.; Tsvetnenko, Y. [Edith Cowan University, Joondalup, WA (Australia)

2009-11-15

Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH similar to 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14% (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.

Toxicity of acid mine pit lake water remediated with limestone and phosphorus.

Science.gov (United States)

Neil, Luke L; McCullough, Clint D; Lund, Mark A; Evans, Louis H; Tsvetnenko, Yuri

2009-11-01

Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH approximately 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and (c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14% (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.

Petrophysical and transport parameters evolution during acid percolation through structurally different limestones

Science.gov (United States)

Martinez Perez, Laura; Luquot, Linda

2017-04-01

Processes affecting geological media often show complex and unpredictable behavior due to the presence of heterogeneities. This remains problematic when facing contaminant transport problems, in the CO2 storage industry or dealing with the mechanisms underneath natural processes where chemical reactions can be observed during the percolation of rock non-equilibrated fluid (e.g. karst formation, seawater intrusion). To understand the mechanisms taking place in a porous medium as a result of this water-rock interaction, we need to know the flow parameters that control them, and how they evolve with time as a result of that concurrence. This is fundamental to ensure realistic predictions of the behavior of natural systems in response of reactive transport processes. We investigate the coupled influence of structural and hydrodynamic heterogeneities in limestone rock samples tracking its variations during chemical reactions. To do so we use laboratory petrophysical techniques such as helium porosimetry, gas permeability, centrifugue, electrical resistivity and sonic waves measurements to obtain the parameters that characterize flow within rock matrix (porosity, permeability, retention curve and pore size distribution, electrical conductivity, formation factor, cementation index and tortuosity) before and after percolation experiments. We built an experimental setup that allows injection of acid brine into core samples under well controlled conditions, monitor changes in hydrodynamic properties and obtain the chemical composition of the injected solution at different stages. 3D rock images were also acquired before and after the experiments using a micro-CT to locate the alteration processes and perform an acurate analysis of the structural changes. Two limestones with distinct textural classification and thus contrasting transport properties have been used in the laboratory experiments: a crinoid limestone and an oolithic limestone. Core samples dimensions were 1 inch

Searching for an Accurate Marker-Based Prediction of an Individual Quantitative Trait in Molecular Plant Breeding.

Science.gov (United States)

Fu, Yong-Bi; Yang, Mo-Hua; Zeng, Fangqin; Biligetu, Bill

2017-01-01

Molecular plant breeding with the aid of molecular markers has played an important role in modern plant breeding over the last two decades. Many marker-based predictions for quantitative traits have been made to enhance parental selection, but the trait prediction accuracy remains generally low, even with the aid of dense, genome-wide SNP markers. To search for more accurate trait-specific prediction with informative SNP markers, we conducted a literature review on the prediction issues in molecular plant breeding and on the applicability of an RNA-Seq technique for developing function-associated specific trait (FAST) SNP markers. To understand whether and how FAST SNP markers could enhance trait prediction, we also performed a theoretical reasoning on the effectiveness of these markers in a trait-specific prediction, and verified the reasoning through computer simulation. To the end, the search yielded an alternative to regular genomic selection with FAST SNP markers that could be explored to achieve more accurate trait-specific prediction. Continuous search for better alternatives is encouraged to enhance marker-based predictions for an individual quantitative trait in molecular plant breeding.

A Novel Fibrosis Index Comprising a Non-Cholesterol Sterol Accurately Predicts HCV-Related Liver Cirrhosis

DEFF Research Database (Denmark)

Ydreborg, Magdalena; Lisovskaja, Vera; Lagging, Martin

2014-01-01

of the present study was to create a model for accurate prediction of liver cirrhosis based on patient characteristics and biomarkers of liver fibrosis, including a panel of non-cholesterol sterols reflecting cholesterol synthesis and absorption and secretion. We evaluated variables with potential predictive...

Holocene limestones of part of the western continental shelf of India

Digital Repository Service at National Institute of Oceanography (India)

Nair, R.R.; Hashimi, N.H.; Guptha, M.V.S.

, while those on te upper continental slope (130-180 m) are algal bryozoan limestones. The limestones have a radiocarbon age ranging between 9,000 and 11,000 years. Depositional environmental on the continental shelf during the Holocene appears...

Effect of limestone particle size on egg production and eggshell ...

African Journals Online (AJOL)

Different limestone particle sizes had no effect on any of the tested egg production and eggshell quality parameters. These results suggested that larger particles limestone are not necessarily essential to provide sufficient Ca2+ to laying hens for egg production and eggshell quality at end-of-lay, provided that the dietary Ca ...

LocARNA-P: Accurate boundary prediction and improved detection of structural RNAs

DEFF Research Database (Denmark)

Will, Sebastian; Joshi, Tejal; Hofacker, Ivo L.

2012-01-01

Current genomic screens for noncoding RNAs (ncRNAs) predict a large number of genomic regions containing potential structural ncRNAs. The analysis of these data requires highly accurate prediction of ncRNA boundaries and discrimination of promising candidate ncRNAs from weak predictions. Existing...... methods struggle with these goals because they rely on sequence-based multiple sequence alignments, which regularly misalign RNA structure and therefore do not support identification of structural similarities. To overcome this limitation, we compute columnwise and global reliabilities of alignments based...... on sequence and structure similarity; we refer to these structure-based alignment reliabilities as STARs. The columnwise STARs of alignments, or STAR profiles, provide a versatile tool for the manual and automatic analysis of ncRNAs. In particular, we improve the boundary prediction of the widely used nc...

Do Dual-Route Models Accurately Predict Reading and Spelling Performance in Individuals with Acquired Alexia and Agraphia?

OpenAIRE

Rapcsak, Steven Z.; Henry, Maya L.; Teague, Sommer L.; Carnahan, Susan D.; Beeson, Pélagie M.

2007-01-01

Coltheart and colleagues (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001; Castles, Bates, & Coltheart, 2006) have demonstrated that an equation derived from dual-route theory accurately predicts reading performance in young normal readers and in children with reading impairment due to developmental dyslexia or stroke. In this paper we present evidence that the dual-route equation and a related multiple regression model also accurately predict both reading and spelling performance in adult...

Towards accurate performance prediction of a vertical axis wind turbine operating at different tip speed ratios

NARCIS (Netherlands)

Rezaeiha, A.; Kalkman, I.; Blocken, B.J.E.

2017-01-01

Accurate prediction of the performance of a vertical-axis wind turbine (VAWT) using CFD simulation requires the employment of a sufficiently fine azimuthal increment (dθ) combined with a mesh size at which essential flow characteristics can be accurately resolved. Furthermore, the domain size needs

Integrated Characterization of DNAPL Source Zone Architecture in Clay Till and Limestone Bedrock

DEFF Research Database (Denmark)

Broholm, Mette Martina; Janniche, Gry Sander; Fjordbøge, Annika Sidelmann

2014-01-01

Background/Objectives. Characterization of dense non-aqueous phase liquid (DNAPL) source zone architecture is essential to develop accurate site specific conceptual models, delineate and quantify contaminant mass, perform risk assessment, and select and design remediation alternatives. The activi......Background/Objectives. Characterization of dense non-aqueous phase liquid (DNAPL) source zone architecture is essential to develop accurate site specific conceptual models, delineate and quantify contaminant mass, perform risk assessment, and select and design remediation alternatives...... innovative investigation methods and characterize the source zone hydrogeology and contamination to obtain an improved conceptual understanding of DNAPL source zone architecture in clay till and bryozoan limestone bedrock. Approach/Activities. A wide range of innovative and current site investigative tools...... for direct and indirect documentation and/or evaluation of DNAPL presence were combined in a multiple lines of evidence approach. Results/Lessons Learned. Though no single technique was sufficient for characterization of DNAPL source zone architecture, the combined use of membrane interphase probing (MIP...

High Resolution ground penetrating radar (GPR) measurements at the laboratory scale to model porosity and permeability in the Miami Limestone in South Florida.

Science.gov (United States)

Mount, G. J.; Comas, X.

2015-12-01

Subsurface water flow within the Biscayne aquifer is controlled by the heterogeneous distribution of porosity and permeability in the karst Miami Limestone and the presence of numerous dissolution and mega-porous features. The dissolution features and other high porosity areas can create preferential flow paths and direct recharge to the aquifer, which may not be accurately conceptualized in groundwater flow models. As hydrologic conditions are undergoing restoration in the Everglades, understanding the distribution of these high porosity areas within the subsurface would create a better understanding of subsurface flow. This research utilizes ground penetrating radar to estimate the spatial variability of porosity and dielectric permittivity of the Miami Limestone at centimeter scale resolution at the laboratory scale. High frequency GPR antennas were used to measure changes in electromagnetic wave velocity through limestone samples under varying volumetric water contents. The Complex Refractive Index Model (CRIM) was then applied in order to estimate porosity and dielectric permittivity of the solid phase of the limestone. Porosity estimates ranged from 45.2-66.0% from the CRIM model and correspond well with estimates of porosity from analytical and digital image techniques. Dielectric permittivity values of the limestone solid phase ranged from 7.0 and 13.0, which are similar to values in the literature. This research demonstrates the ability of GPR to identify the cm scale spatial variability of aquifer properties that influence subsurface water flow which could have implications for groundwater flow models in the Biscayne and potentially other shallow karst aquifers.

Bayesian calibration of power plant models for accurate performance prediction

International Nuclear Information System (INIS)

Boksteen, Sowande Z.; Buijtenen, Jos P. van; Pecnik, Rene; Vecht, Dick van der

2014-01-01

Highlights: • Bayesian calibration is applied to power plant performance prediction. • Measurements from a plant in operation are used for model calibration. • A gas turbine performance model and steam cycle model are calibrated. • An integrated plant model is derived. • Part load efficiency is accurately predicted as a function of ambient conditions. - Abstract: Gas turbine combined cycles are expected to play an increasingly important role in the balancing of supply and demand in future energy markets. Thermodynamic modeling of these energy systems is frequently applied to assist in decision making processes related to the management of plant operation and maintenance. In most cases, model inputs, parameters and outputs are treated as deterministic quantities and plant operators make decisions with limited or no regard of uncertainties. As the steady integration of wind and solar energy into the energy market induces extra uncertainties, part load operation and reliability are becoming increasingly important. In the current study, methods are proposed to not only quantify various types of uncertainties in measurements and plant model parameters using measured data, but to also assess their effect on various aspects of performance prediction. The authors aim to account for model parameter and measurement uncertainty, and for systematic discrepancy of models with respect to reality. For this purpose, the Bayesian calibration framework of Kennedy and O’Hagan is used, which is especially suitable for high-dimensional industrial problems. The article derives a calibrated model of the plant efficiency as a function of ambient conditions and operational parameters, which is also accurate in part load. The article shows that complete statistical modeling of power plants not only enhances process models, but can also increases confidence in operational decisions

Coralgal facies of the Upper Eocene-Lower Oligocene limestones in Letca-Rastoci area

Directory of Open Access Journals (Sweden)

Ioana Prica

2001-09-01

Full Text Available In this paper are described the coralgal facies identified in the Upper Eocene-Lower Oligocene limestone succession (Cozla Formation outcropping in two quarries at Letca and Rastoci (Sălaj district, Romania. In the studied profiles the coral and algae limestones are interlayered with bioclastic limestones with foraminifera. On the top of relatively deep water deposits, coral and algae crusts and dendritic corals coated by algae were deposited. The environment registered a gradual deepening, the deposits being completely immersed, while bioclastic limestones with foraminifera were recurrently formed. This cycle is repeated, the whole succession being caracterized by several such “parasequences”.

Techniques for Source Zone and Plume Characterization of Tetrachloroethene in Fractured Limestone Aquifers

DEFF Research Database (Denmark)

Fjordbøge, Annika Sidelmann; Mosthaf, Klaus; Janniche, Gry S.

Characterization of chlorinated solvents in fractured limestone aquifers is essential for proper development of site specific conceptual models and subsequent risk assessment and remediation. High resolution characterization is challenged by the difficulties involved in collection of intact core...... an improved conceptual understanding of contaminant transport. At both sites limestone cores were collected with significant core losses. The discrete quantification of chlorinated solvents in the retrieved limestone cores was compared to different FLUTe technologies at the DNAPL site and passive and active...... distribution compared to the data obtained by quantification of chlorinated solvents in the limestone cores....

Electrokinetically Enhanced Delivery for ERD Remediation of Chlorinated Ethenes in a Fractured Limestone Aquifer

DEFF Research Database (Denmark)

Broholm, Mette Martina; Hyldegaard, Bente Højlund; With Nedergaard, Lærke

causing very long remediation timeframes. Electrokinetics (EK) offers some unique transport processes, which can potentially overcome the diffusion limitations in the matrix. A novel technology combines ERD and EK for enhanced delivery. The combined technology (EK-BIO) has shown promising results in clay....... Experimental work on EK-BIO in limestone was conducted in a laboratory setup with limestone cores. EK was demonstrated to be promising in establishing enhanced contact between the donor lactate, bacteria, and cis-DCE within the limestone matrix. Complete dechlorination is expected to take place in the matrix......, since back diffusion limitations in the limestone matrix are overcome. This is essential for the overall time perspective of a remediation in limestone aquifers....

Oriented nucleation and growth of anhydrite during direct sulfation of limestone

DEFF Research Database (Denmark)

Hu, Guilin; Dam-Johansen, Kim; Wedel, Stig

2008-01-01

The direct sulfation of limestone (Iceland Spar) was studied at 973 K in a fixed-bed reactor. Scanning electron microscopy examinations of the sulfated limestone particles show that the sulfation process involves oriented nucleation and growth of the solid product, anhydrite. The reason...

Accurate Holdup Calculations with Predictive Modeling & Data Integration

Energy Technology Data Exchange (ETDEWEB)

Azmy, Yousry [North Carolina State Univ., Raleigh, NC (United States). Dept. of Nuclear Engineering; Cacuci, Dan [Univ. of South Carolina, Columbia, SC (United States). Dept. of Mechanical Engineering

2017-04-03

In facilities that process special nuclear material (SNM) it is important to account accurately for the fissile material that enters and leaves the plant. Although there are many stages and processes through which materials must be traced and measured, the focus of this project is material that is “held-up” in equipment, pipes, and ducts during normal operation and that can accumulate over time into significant quantities. Accurately estimating the holdup is essential for proper SNM accounting (vis-à-vis nuclear non-proliferation), criticality and radiation safety, waste management, and efficient plant operation. Usually it is not possible to directly measure the holdup quantity and location, so these must be inferred from measured radiation fields, primarily gamma and less frequently neutrons. Current methods to quantify holdup, i.e. Generalized Geometry Holdup (GGH), primarily rely on simple source configurations and crude radiation transport models aided by ad hoc correction factors. This project seeks an alternate method of performing measurement-based holdup calculations using a predictive model that employs state-of-the-art radiation transport codes capable of accurately simulating such situations. Inverse and data assimilation methods use the forward transport model to search for a source configuration that best matches the measured data and simultaneously provide an estimate of the level of confidence in the correctness of such configuration. In this work the holdup problem is re-interpreted as an inverse problem that is under-determined, hence may permit multiple solutions. A probabilistic approach is applied to solving the resulting inverse problem. This approach rates possible solutions according to their plausibility given the measurements and initial information. This is accomplished through the use of Bayes’ Theorem that resolves the issue of multiple solutions by giving an estimate of the probability of observing each possible solution. To use

Limestone attrition under simulated oxyfiring Fluidized-Bed combustion conditions

Energy Technology Data Exchange (ETDEWEB)

Scala, F. [Istituto di Ricerche sulla Combustione - CNR, Napoli (Italy); Salatino, P. [Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Napoli (Italy)

2009-03-15

Limestone attrition by surface wear was studied during the flue gas desulfurization under simulated fluidized-bed (FB) oxyfiring conditions and hindered calcination. Bench-scale experimental tests were carried out using well-established techniques previously developed for the characterization of sulfation and attrition of sorbents in air-blown atmospheric FB combustors. The experimental limestone conversion and attrition results were compared with those previously obtained with the same limestone under simulated air-blown combustion conditions. The differences in the conversion and attrition extents and patterns associated with oxyfiring as compared to air-blown atmospheric combustion were highlighted and related to the different particle morphologies and thicknesses of the sulfate layer. It was noted that attrition could play an important role in practical circulating FB combustor operation, by effectively enhancing particle sulfation under both oxyfiring and air-blown combustion conditions. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Fast and Accurate Prediction of Stratified Steel Temperature During Holding Period of Ladle

Science.gov (United States)

Deodhar, Anirudh; Singh, Umesh; Shukla, Rishabh; Gautham, B. P.; Singh, Amarendra K.

2017-04-01

Thermal stratification of liquid steel in a ladle during the holding period and the teeming operation has a direct bearing on the superheat available at the caster and hence on the caster set points such as casting speed and cooling rates. The changes in the caster set points are typically carried out based on temperature measurements at the end of tundish outlet. Thermal prediction models provide advance knowledge of the influence of process and design parameters on the steel temperature at various stages. Therefore, they can be used in making accurate decisions about the caster set points in real time. However, this requires both fast and accurate thermal prediction models. In this work, we develop a surrogate model for the prediction of thermal stratification using data extracted from a set of computational fluid dynamics (CFD) simulations, pre-determined using design of experiments technique. Regression method is used for training the predictor. The model predicts the stratified temperature profile instantaneously, for a given set of process parameters such as initial steel temperature, refractory heat content, slag thickness, and holding time. More than 96 pct of the predicted values are within an error range of ±5 K (±5 °C), when compared against corresponding CFD results. Considering its accuracy and computational efficiency, the model can be extended for thermal control of casting operations. This work also sets a benchmark for developing similar thermal models for downstream processes such as tundish and caster.

Accurate prediction of the enthalpies of formation for xanthophylls.

Science.gov (United States)

Lii, Jenn-Huei; Liao, Fu-Xing; Hu, Ching-Han

2011-11-30

This study investigates the applications of computational approaches in the prediction of enthalpies of formation (ΔH(f)) for C-, H-, and O-containing compounds. Molecular mechanics (MM4) molecular mechanics method, density functional theory (DFT) combined with the atomic equivalent (AE) and group equivalent (GE) schemes, and DFT-based correlation corrected atomization (CCAZ) were used. We emphasized on the application to xanthophylls, C-, H-, and O-containing carotenoids which consist of ∼ 100 atoms and extended π-delocaization systems. Within the training set, MM4 predictions are more accurate than those obtained using AE and GE; however a systematic underestimation was observed in the extended systems. ΔH(f) for the training set molecules predicted by CCAZ combined with DFT are in very good agreement with the G3 results. The average absolute deviations (AADs) of CCAZ combined with B3LYP and MPWB1K are 0.38 and 0.53 kcal/mol compared with the G3 data, and are 0.74 and 0.69 kcal/mol compared with the available experimental data, respectively. Consistency of the CCAZ approach for the selected xanthophylls is revealed by the AAD of 2.68 kcal/mol between B3LYP-CCAZ and MPWB1K-CCAZ. Copyright © 2011 Wiley Periodicals, Inc.

Searching for an Accurate Marker-Based Prediction of an Individual Quantitative Trait in Molecular Plant Breeding

Directory of Open Access Journals (Sweden)

Yong-Bi Fu

2017-07-01

Full Text Available Molecular plant breeding with the aid of molecular markers has played an important role in modern plant breeding over the last two decades. Many marker-based predictions for quantitative traits have been made to enhance parental selection, but the trait prediction accuracy remains generally low, even with the aid of dense, genome-wide SNP markers. To search for more accurate trait-specific prediction with informative SNP markers, we conducted a literature review on the prediction issues in molecular plant breeding and on the applicability of an RNA-Seq technique for developing function-associated specific trait (FAST SNP markers. To understand whether and how FAST SNP markers could enhance trait prediction, we also performed a theoretical reasoning on the effectiveness of these markers in a trait-specific prediction, and verified the reasoning through computer simulation. To the end, the search yielded an alternative to regular genomic selection with FAST SNP markers that could be explored to achieve more accurate trait-specific prediction. Continuous search for better alternatives is encouraged to enhance marker-based predictions for an individual quantitative trait in molecular plant breeding.

Searching for an Accurate Marker-Based Prediction of an Individual Quantitative Trait in Molecular Plant Breeding

Science.gov (United States)

Fu, Yong-Bi; Yang, Mo-Hua; Zeng, Fangqin; Biligetu, Bill

2017-01-01

Molecular plant breeding with the aid of molecular markers has played an important role in modern plant breeding over the last two decades. Many marker-based predictions for quantitative traits have been made to enhance parental selection, but the trait prediction accuracy remains generally low, even with the aid of dense, genome-wide SNP markers. To search for more accurate trait-specific prediction with informative SNP markers, we conducted a literature review on the prediction issues in molecular plant breeding and on the applicability of an RNA-Seq technique for developing function-associated specific trait (FAST) SNP markers. To understand whether and how FAST SNP markers could enhance trait prediction, we also performed a theoretical reasoning on the effectiveness of these markers in a trait-specific prediction, and verified the reasoning through computer simulation. To the end, the search yielded an alternative to regular genomic selection with FAST SNP markers that could be explored to achieve more accurate trait-specific prediction. Continuous search for better alternatives is encouraged to enhance marker-based predictions for an individual quantitative trait in molecular plant breeding. PMID:28729875

Deterioration of limestone aggregate mortars by liquid sodium in fast breeder reactor environment

Energy Technology Data Exchange (ETDEWEB)

Mohammed Haneefa, K., E-mail: mhkolakkadan@gmail.com [Department of Civil Engineering, IIT Madras, Chennai (India); Santhanam, Manu [Department of Civil Engineering, IIT Madras, Chennai (India); Parida, F.C. [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

2014-08-15

Highlights: • Limestone mortars were exposed to liquid sodium exposure at 550 °C. • Micro-analytical techniques were used to characterize the exposed specimens. • The performance of limestone mortar was greatly influenced by w/c. • The fundamental degradation mechanisms of limestone mortars were identified. - Abstract: Hot liquid sodium at 550 °C can interact with concrete in the scenario of an accidental spillage of sodium in liquid metal cooled fast breeder reactors. To protect the structural concrete from thermo-chemical degradation, a sacrificial layer of limestone aggregate concrete is provided over it. This study investigates the fundamental mechanisms of thermo-chemical interaction between the hot liquid sodium and limestone mortars at 550 °C for a duration of 30 min in open air. The investigation involves four different types of cement with variation of water-to-cement ratios (w/c) from 0.4 to 0.6. Comprehensive analysis of experimental results reveals that the degree of damage experienced by limestone mortars displayed an upward trend with increase in w/c ratios for a given type of cement. Performance of fly ash based Portland pozzolana cement was superior to other types of cements for a w/c of 0.55. The fundamental degradation mechanisms of limestone mortars during hot liquid sodium interactions include alterations in cement paste phase, formation of sodium compounds from the interaction between solid phases of cement paste and aggregate, modifications of interfacial transition zone (ITZ), decomposition of CaCO{sub 3}, widening and etching of rhombohedral cleavages, and subsequent breaking through the weakest rhombohedral cleavage planes of calcite, staining, ferric oxidation in grain boundaries and disintegration of impurity minerals in limestone.

Deterioration of limestone aggregate mortars by liquid sodium in fast breeder reactor environment

International Nuclear Information System (INIS)

Mohammed Haneefa, K.; Santhanam, Manu; Parida, F.C.

2014-01-01

Highlights: • Limestone mortars were exposed to liquid sodium exposure at 550 °C. • Micro-analytical techniques were used to characterize the exposed specimens. • The performance of limestone mortar was greatly influenced by w/c. • The fundamental degradation mechanisms of limestone mortars were identified. - Abstract: Hot liquid sodium at 550 °C can interact with concrete in the scenario of an accidental spillage of sodium in liquid metal cooled fast breeder reactors. To protect the structural concrete from thermo-chemical degradation, a sacrificial layer of limestone aggregate concrete is provided over it. This study investigates the fundamental mechanisms of thermo-chemical interaction between the hot liquid sodium and limestone mortars at 550 °C for a duration of 30 min in open air. The investigation involves four different types of cement with variation of water-to-cement ratios (w/c) from 0.4 to 0.6. Comprehensive analysis of experimental results reveals that the degree of damage experienced by limestone mortars displayed an upward trend with increase in w/c ratios for a given type of cement. Performance of fly ash based Portland pozzolana cement was superior to other types of cements for a w/c of 0.55. The fundamental degradation mechanisms of limestone mortars during hot liquid sodium interactions include alterations in cement paste phase, formation of sodium compounds from the interaction between solid phases of cement paste and aggregate, modifications of interfacial transition zone (ITZ), decomposition of CaCO 3 , widening and etching of rhombohedral cleavages, and subsequent breaking through the weakest rhombohedral cleavage planes of calcite, staining, ferric oxidation in grain boundaries and disintegration of impurity minerals in limestone

XenoSite: accurately predicting CYP-mediated sites of metabolism with neural networks.

Science.gov (United States)

Zaretzki, Jed; Matlock, Matthew; Swamidass, S Joshua

2013-12-23

Understanding how xenobiotic molecules are metabolized is important because it influences the safety, efficacy, and dose of medicines and how they can be modified to improve these properties. The cytochrome P450s (CYPs) are proteins responsible for metabolizing 90% of drugs on the market, and many computational methods can predict which atomic sites of a molecule--sites of metabolism (SOMs)--are modified during CYP-mediated metabolism. This study improves on prior methods of predicting CYP-mediated SOMs by using new descriptors and machine learning based on neural networks. The new method, XenoSite, is faster to train and more accurate by as much as 4% or 5% for some isozymes. Furthermore, some "incorrect" predictions made by XenoSite were subsequently validated as correct predictions by revaluation of the source literature. Moreover, XenoSite output is interpretable as a probability, which reflects both the confidence of the model that a particular atom is metabolized and the statistical likelihood that its prediction for that atom is correct.

0-6686 : improving DMS 9210 requirements for limestone rock asphalt : [project summary].

Science.gov (United States)

2013-08-01

Limestone rock asphalt (LRA) mixtures have : been produced and placed for several decades : using specification requirements currently listed : under DMS 9210, Limestone Rock Asphalt (LRA). : Several Texas Department of Transportation : (TxDOT) distr...

Face logging in Copenhagen Limestone, Denmark

DEFF Research Database (Denmark)

Jakobsen, Lisa; Foged, Niels Nielsen; Erichsen, Lars

2015-01-01

tunnel in Copenhagen more than 2.5 km face logs were made in 467 locations at underground stations, shafts, caverns and along bored tunnels. Over 160 geotechnical boreholes, many with geophysical logging were executed prior to construction works. The bedrock consists of Paleogene "Copenhagen limestone......The requirement for excavation support can be assessed from face logging. Face logs can also improve our knowledge of lithological and structural conditions within bedrock and supplement information from boreholes and geophysical logs. During the construction of 8 km metro tunnel and 4 km heating....... The induration degrees recorded in face logs and boreholes are compared and correlated. Distinct geophysical log markers are used to divide the limestone into three units. These marker horizons are correlated between face logs and geotechnical boreholes. A 3D model of the strength variations recorded within...

Development of gypsum alteration on marble and limestone

Science.gov (United States)

McGee, E.S.

1996-01-01

Blackened alteration crusts of gypsum plus particulates that form on sheltered areas on marble and limestone buildings pose a challenge for rehabilitation and cleaning. Fresh marble and limestone samples exposed at monitored exposure sites present conditions of simple geometry and well-documented exposures but have short exposure histories (one to five years). The gypsum alteration crusts that develop on these samples provide insight into the early stages and rate of alteration crust formation. Alteration crusts from buildings give a longer, but less well known exposure history and present much more complex surfaces for gypsum accumulation. Integrated observations and measurements of alteration crusts from exposure samples and from buildings identify four factors that are important in the formation and development of alteration crusts on marble and limestone: (1) pollution levels, (2) exposure to rain or washing, (3) geometry of exposure of the stone surface, and (4) permeability of the stone. The combination of these factors contributes to both the distribution and the physical characteristics of the gypsum crusts which may affect cleaning decisions.

Optimisation of a wet FGD pilot plant using fine limestone and organic acids

DEFF Research Database (Denmark)

Frandsen, Jan; Kiil, Søren; Johnsson, Jan Erik

2001-01-01

, but the residual limestone content in the gypsum increased to somewhere between 19 and 30 wt%, making this pH range unsuitable for use in a full-scale plant. The investigations have shown that both the addition of organic acids and the use of a limestone with a fine PSD can be used to optimise wet FGD plants. (C......The effects of adding an organic acid or using a limestone with a fine particle size distribution (PSD) have been examined in a wet flue gas desulphurisation (FGD) pilot plant. Optimisation of the plant with respect to the degree of desulphurisation and the residual limestone content of the gypsum...... has been the aim of the work. In contrast to earlier investigations with organic acids, all essential process parameters (i.e. gas phase concentration profiles of SO(2), slurry pH profiles. and residual limestone in the gypsum) were considered. Slurry concentrations of adipic acid in the range of 0...

Assessment of Environmental Impacts of Limestone Quarrying Operations in Thailand

Science.gov (United States)

Kittipongvises, Suthirat

2017-11-01

Environmental impacts of the mineral extraction have been a public concern. Presently, there is widespread global interest in the area of mining and its sustainability that focused on the need to shift mining industry to a more sustainable framework. The aim of this study was to systematically assess all possible environmental and climate change related impacts of the limestone quarrying operation in Thailand. By considering the life cycle assessment method, the production processes were divided into three phases: raw material extraction, transportation, and comminution. Both IMPACT 2002+ and the Greenhouse Gas Protocol methods were used. Results of IMPACT 2002+ analysis showed that per 1 ton crushed limestone rock production, the total depletion of resource and GHGs emissions were 79.6 MJ and 2.76 kg CO2 eq., respectively. Regarding to the four damage categories, `resources' and `climate change' categories were the two greatest environmental impacts of the limestone rock production. Diesel fuel and electricity consumption in the mining processes were the main causes of those impacts. For climate change, the unit of CO2 eq. was expressed to quantify the total GHGs emissions. Estimated result was about 3.13 kg CO2 eq. per ton limestone rock product. The results obtained by the Greenhouse Gas Protocol were also similar to IMPACT 2002+ method. Electrical energy consumption was considered as the main driver of GHGs, accounting for approximately 46.8 % of total fossil fuel CO2 emissions. A final point should be noted that data uncertainties in environmental assessment over the complete life cycle of limestone quarrying operation have to be carefully considered.

Studies on limestone concrete as a low-activation structural material for nuclear power plants

International Nuclear Information System (INIS)

Uematsu, Mikio; Nagano, Hiroshi; Naito, Yasuhiro

2000-01-01

Because of low content of Li, Co and Eu, the target nuclides of activation reaction, limestone concrete is considered to be effective in reducing the decommissioning cost of nuclear plants. Induced activity calculation and structural strength test were performed for limestone concrete and the results were compared with the data obtained for sandstone concrete, which is generally used in nuclear plants. Minor elements, which are important from the viewpoint of activation, were measured with elementary analysis for limestone samples from three different quarries in Japan. Induced activity in biological shield walls (BSW) of Boiling Water Reactor (BWR) plants was calculated with the isotope generation code ORIGEN-79 using neutron flux data obtained with the one-dimensional Sn transport code ANISN and MGCL 137-group activation cross section library based on JENDL-3. Estimated total radioactivity accumulated in limestone concrete BSW was 5 times lower than that in the sandstone concrete BSW. Structural strength were compared between limestone concrete and sandstone concrete, and limestone concrete was found to have enough compressive strength and tensile strength. (author)

Microbiome Data Accurately Predicts the Postmortem Interval Using Random Forest Regression Models

Directory of Open Access Journals (Sweden)

Aeriel Belk

2018-02-01

Full Text Available Death investigations often include an effort to establish the postmortem interval (PMI in cases in which the time of death is uncertain. The postmortem interval can lead to the identification of the deceased and the validation of witness statements and suspect alibis. Recent research has demonstrated that microbes provide an accurate clock that starts at death and relies on ecological change in the microbial communities that normally inhabit a body and its surrounding environment. Here, we explore how to build the most robust Random Forest regression models for prediction of PMI by testing models built on different sample types (gravesoil, skin of the torso, skin of the head, gene markers (16S ribosomal RNA (rRNA, 18S rRNA, internal transcribed spacer regions (ITS, and taxonomic levels (sequence variants, species, genus, etc.. We also tested whether particular suites of indicator microbes were informative across different datasets. Generally, results indicate that the most accurate models for predicting PMI were built using gravesoil and skin data using the 16S rRNA genetic marker at the taxonomic level of phyla. Additionally, several phyla consistently contributed highly to model accuracy and may be candidate indicators of PMI.

High-temperature CO2 capture cycles of hydrated limestone prepared with aluminum (hydr)oxides derived from kaolin

International Nuclear Information System (INIS)

Wang, Ke; Zhao, Pengfei; Guo, Xin; Han, Dongtai; Chao, Yang

2014-01-01

Highlights: • Hydrated limestone exhibited a higher reactivity and stability. • Microstructure of hydrated limestone was significantly improved. • Hydrated limestone still suffered less loss-incapacity. • Hydrated limestone sorbents with kaolin-based binders were prepared and characterized. • Sorbents prepared from hydrated limestone and Al(OH) 3 binder are a promising sorbent. - Abstract: A simple and convenient process was used to improve the utilization of natural limestone and kaolin for calcium looping technology and environmental applications. The calcined natural limestone modified with the distilled water (denoted as Limestone-W), was systematically studied and compared with the other CaO sorbents (calcium acetate, calcium D-gluconate and calcined natural limestone). These CaO-based sorbents were tested for their CO 2 capture behavior through 20 carbonation/calcination cycles in a thermo-gravimetric analyzer (TGA). Their morphology, pore structure and phase composition before and after carbonation/calcination cycles were determined by scanning electron microscopy, nitrogen adsorption, and X-ray diffraction. The first-cycle and multicycle sorption results revealed that the Limestone-W sorbent exhibited a relatively faster reaction rate and higher cyclic CO 2 capture. The characterization data indicated that the Limestone-W was composed of a special calcium oxide structure with lower crystalline and higher porosity nanoparticles, which appeared to be the main reasons for its higher CO 2 capture capability. However, the Limestone-W still suffered loss of reactivity, even though it was less pronounced than the other CaO sorbent. To avoid this unfavorable effect, a thermally stable inert material (aluminum hydroxide derived from kaolin) was incorporated into the Limestone-W structure. This new sorbent revealed higher stability because the formation of a stable framework of Ca 12 Al 14 O 33 particles hindered densification and sintering of the CaO phase

Improvement of the Early-Age Compressive Strength, Water Permeability, and Sulfuric Acid Resistance of Scoria-Based Mortars/Concrete Using Limestone Filler

Directory of Open Access Journals (Sweden)

Aref Al-Swaidani

2017-01-01

Full Text Available Natural pozzolan is being widely used as cement replacement. Despite the economic, ecological, and technical benefits of its adding, it is often associated with shortcomings such as the need of moist-curing for longer time and a lower early strength. This study is an attempt to investigate the effect of adding limestone filler on the compressive strength and durability of mortars/concrete containing scoria. Sixteen types of binders with different replacement levels of scoria (0, 10, 20, and 30% and limestone (0, 5, 10, and 15% were prepared. The development of the compressive strength of mortar/concrete specimens was investigated after 2, 7, 28, and 90 days’ curing. In addition, the acid resistance of the 28 days’ cured mortars was evaluated after 90 days’ exposure to 5% H2SO4. Concrete permeability was also evaluated after 2, 7, 28, and 90 days’ curing. Test results revealed that there was an increase in the early-age compressive strength and a decrease in water penetration depths with adding limestone filler. Contrary to expectation, the best acid resistance to 5% H2SO4 solution was noted in the mortars containing 15% limestone. Based on the results obtained, an empirical equation was derived to predict the compressive strength of mortars.

Effects of phosphate limestone on structure and quality under sugarcane vertisoles

Directory of Open Access Journals (Sweden)

Pedro Cairo Cairo

2017-10-01

Full Text Available The work was developed in sugarcane areas of cuban vertisols of the north coast of the province of Villa Clara municipality of Sagua la Grande, with the aim of evaluating the effectiveness of phosphate limestone and their combinations with fertilizers and organic manure on the structure and quality of vertisols under sugarcane cultivation. An experiment with phosphate limestone levels and combinations with organic manure (compost, filter cake and fertilizers (NPK was carried out on a wasstrip-block design. A soil analysis was performedat the depth of 0-20 and 20 -40 cm 36 months after the application of treatments. Organic matter, stable aggregates, factor structure, permeability, T value, exchangeable cations, index soil quality and productivity of sugarcane were evaluated. Phosphate limestone and there combinations with organic manures manifested significant effects on soil structure both in the surface layer and subsurface with residual impact over time to 36 months. The results show the close relationship between phosphate limestone and there combinations with organic manures on soil quality index additive, yield of sugarcane and economic impact.

Accelerated weathering of limestone for CO2 mitigation opportunities for the stone and cement industries

Science.gov (United States)

Langer, W.H.; Juan, C.A.S.; Rau, G.H.; Caldeira, K.

2009-01-01

Large amounts of limestone fines coproduced during the processing of crushed limestone may be useful in the sequestration of carbon dioxide (CO 2). Accelerated weathering of limestone (AWL) is proposed as a low-tech method to capture and sequester CO2 from fossil fuel-fired power plants and other point-sources such as cement manufacturing. AWL reactants are readily available, inexpensive, and environmentally benign. Waste CO 2 is hydrated with water to produce carbonic acid, which then reacts with and is neutralized by limestone fines, thus converting CO2 gas to dissolved calcium bicarbonate. AWL waste products can be disposed of in the ocean. Feasibility requires access to an inexpensive source of limestone and to seawater, thus limiting AWL facilities within about 10 km of the coastline. The majority of U.S. coastal power generating facilities are within economical transport distance of limestone resources. AWL presents opportunities for collaborative efforts among the crushed stone industry, electrical utilities, cement manufactures, and research scientists.

Towards Accurate Prediction of Unbalance Response, Oil Whirl and Oil Whip of Flexible Rotors Supported by Hydrodynamic Bearings

Directory of Open Access Journals (Sweden)

Rob Eling

2016-09-01

Full Text Available Journal bearings are used to support rotors in a wide range of applications. In order to ensure reliable operation, accurate analyses of these rotor-bearing systems are crucial. Coupled analysis of the rotor and the journal bearing is essential in the case that the rotor is flexible. The accuracy of prediction of the model at hand depends on its comprehensiveness. In this study, we construct three bearing models of increasing modeling comprehensiveness and use these to predict the response of two different rotor-bearing systems. The main goal is to evaluate the correlation with measurement data as a function of modeling comprehensiveness: 1D versus 2D pressure prediction, distributed versus lumped thermal model, Newtonian versus non-Newtonian fluid description and non-mass-conservative versus mass-conservative cavitation description. We conclude that all three models predict the existence of critical speeds and whirl for both rotor-bearing systems. However, the two more comprehensive models in general show better correlation with measurement data in terms of frequency and amplitude. Furthermore, we conclude that a thermal network model comprising temperature predictions of the bearing surroundings is essential to obtain accurate predictions. The results of this study aid in developing accurate and computationally-efficient models of flexible rotors supported by plain journal bearings.

CARBONIFEROUS CORALS AND CHAETETIDS FROM EXOTIC LIMESTONE BLOCK OF THE CRIMEA

Directory of Open Access Journals (Sweden)

VICTOR OGAR

2015-11-01

Full Text Available A chaetetid sponge and coral fauna from a Carboniferous exotic limestone block in the Lower Jurassic Esciorda olistostrome on the Bodrak River (Crimean Mountains are described for the first time. The Bodrak exotic block is composed of massive limestone. It contains the chaetetid Chaetetes (Boswellia sp., the tabulate coral Multithecopora sp., and poorly preserved rugose corals, including Dibunophyllum? sp., Cordibia? sp. and gen. et sp. indet. Only the fasciculate colonies of the rugose coral Lytvophyllum askynensis (Kossovaya, 2009 are confidently identified. The studied association of fossils is similar to that of the Donets Basin and the Urals and confirms the Lower Bashkirian age of the Bodrak limestone block. 

Assessment of Environmental Impacts of Limestone Quarrying Operations in Thailand

Directory of Open Access Journals (Sweden)

Kittipongvises Suthirat

2017-11-01

Full Text Available Environmental impacts of the mineral extraction have been a public concern. Presently, there is widespread global interest in the area of mining and its sustainability that focused on the need to shift mining industry to a more sustainable framework. The aim of this study was to systematically assess all possible environmental and climate change related impacts of the limestone quarrying operation in Thailand. By considering the life cycle assessment method, the production processes were divided into three phases: raw material extraction, transportation, and comminution. Both IMPACT 2002+ and the Greenhouse Gas Protocol methods were used. Results of IMPACT 2002+ analysis showed that per 1 ton crushed limestone rock production, the total depletion of resource and GHGs emissions were 79.6 MJ and 2.76 kg CO2 eq., respectively. Regarding to the four damage categories, ‘resources’ and ‘climate change’ categories were the two greatest environmental impacts of the limestone rock production. Diesel fuel and electricity consumption in the mining processes were the main causes of those impacts. For climate change, the unit of CO2 eq. was expressed to quantify the total GHGs emissions. Estimated result was about 3.13 kg CO2 eq. per ton limestone rock product. The results obtained by the Greenhouse Gas Protocol were also similar to IMPACT 2002+ method. Electrical energy consumption was considered as the main driver of GHGs, accounting for approximately 46.8 % of total fossil fuel CO2 emissions. A final point should be noted that data uncertainties in environmental assessment over the complete life cycle of limestone quarrying operation have to be carefully considered.

The Solnhofen Limestone: A stony heritage of many uses

Science.gov (United States)

Kölbl-Ebert, Martina; Kramar, Sabina; Cooper, Barry J.

2016-04-01

High above the valley of the River Altmühl (Bavaria, Germany), between Solnhofen to the west and Kelheim to the east, numerous quarries give access to thinly plated limestone from the Upper Jurassic, some 150 million years before the present. The main quarry areas lie around the town of Eichstätt and between the villages of Solnhofen, Langenaltheim and Mörnsheim. Here limestone slabs have been quarried for several hundred years, some even in Roman times. Solnhofen Limestone is famous worldwide; not only because it is a beautiful building stone of high quality, but also because of the exceptionally well-preserved fossils it contains -among them the early bird Archaeopteryx. The quarry industry between Solnhofen and Eichstätt has shaped a cultural landscape, with old and new quarries sunk into the plain and numerous spoil heaps rising above it, for the rock is not all economically useful. But many of the spoil heaps and the old quarries are environmentally protected as they provide a habitat for some rare plants and animals. It is not necessary to cut the Solnhofen Limestone with a saw: it is split by hand into thin and even slabs or sheets which are used for flagstones and wall covers, which since centuries are sold world-wide. Locally it also serves as roof tiles for traditional houses. Thick slabs of especially fine quality may be found near Solnhofen and Mörnsheim and are used for lithography printing.

Accurate wavelength prediction of photonic crystal resonant reflection and applications in refractive index measurement

DEFF Research Database (Denmark)

Hermannsson, Pétur Gordon; Vannahme, Christoph; Smith, Cameron L. C.

2014-01-01

and superstrate materials. The importance of accounting for material dispersion in order to obtain accurate simulation results is highlighted, and a method for doing so using an iterative approach is demonstrated. Furthermore, an application for the model is demonstrated, in which the material dispersion......In the past decade, photonic crystal resonant reflectors have been increasingly used as the basis for label-free biochemical assays in lab-on-a-chip applications. In both designing and interpreting experimental results, an accurate model describing the optical behavior of such structures...... is essential. Here, an analytical method for precisely predicting the absolute positions of resonantly reflected wavelengths is presented. The model is experimentally verified to be highly accurate using nanoreplicated, polymer-based photonic crystal grating reflectors with varying grating periods...

Quantitative measurements of fly ash, slag, and cement in limestone-based blends by Fourier transform infrared-attenuated total reflectance method

International Nuclear Information System (INIS)

Rebagay, T.V.; Dodd, D.A.; Claghorn, R.D.; Voogd, J.A.

1991-02-01

The disposal of the low-level radioactive liquids involves mixing the liquid waste with pozzolanic blend to form grout. Since the long-term performance of the grout depends on the composition of the blend, a rapid and reliable quantitative method to monitor blend compositions is needed. Earlier studies by Westinghouse Hanford Company demonstrated the utility of a Fourier transform infrared-attenuated total reflectance method for the analysis of cement blends. A sequential spectral subtraction technique was used to analyze the blend; however, its reproducibility depends on the operator's skill to perform spectral subtractions. A partial-least-squares (PLS) algorithm has replaced spectral subtraction. The PLS method is a statistical quantitative method suitable for analysis of multicomponent systems. Calibration blends are prepared by mixing the blend components in various proportions following a carefully designed calibration model. For the model, limestone content ranges from 30-50 wt%; blast furnace slag from 18-38 wt%; fly ash from 18-38 wt%; and cement from 0-16 wt%. Use of the large concentration range will enhance the chance that the calibration will be useful when target concentration change. The ability of the PLS method to predict limestone, slag, fly ash, and cement values in test blends was assessed. The prediction step of the PLS algorithm required only a few seconds to analyze the test spectra. The best and worst results for each component of the blends calculated by this method are shown in tables. The standard error of prediction of the true value is <2 wt% for limestone, <4 wt% for both fly ash and blast furnace slag, and <10 wt% for cement. 2 refs., 8 figs., 7 tabs

Evaluation of the Efficiency of Limestone Powder in Concrete and the Effects on the Environment

Directory of Open Access Journals (Sweden)

Yoo-Jae Kim

2018-02-01

Full Text Available The major environmental impact of concrete comes from the CO2 emissions, produced during the cement manufacturing process. The main goal of this research project is to evaluate the efficiency of limestone powder as a partial cement replacement, in order to reduce energy consumption and CO2 emissions. This study utilizes limestone powders, with different particle sizes, to replace a portion of Portland cement using various ratios. Due to the dilution effect when partially replacing cement, there is a reduction in the concrete’s physical properties. To assess the dilution effect, a modification to Féret’s equation is used to calculate an efficiency factor for the limestone powder when compared to cement. To measure the environmental impact, a life cycle assessment is conducted on concrete made with limestone powder combined with cement. This allows for an evaluation of the various cement/limestone powder ratios that will maximize the environmental benefit, with minimal reduction in concrete strength. Additional microstructural analysis using petrographic examination was completed to provide a visual understanding of the distribution of the limestone particles within the cement paste. The results indicate that the efficiency of limestone powder in partially replacing cement can be achieved by particle packing and particle distribution in the concrete and the benefits of emission reductions exceed the loss in compressive strength when higher levels of limestone powder is used to replace cement.

Meta-analytic approach to the accurate prediction of secreted virulence effectors in gram-negative bacteria

Directory of Open Access Journals (Sweden)

Sato Yoshiharu

2011-11-01

Full Text Available Abstract Background Many pathogens use a type III secretion system to translocate virulence proteins (called effectors in order to adapt to the host environment. To date, many prediction tools for effector identification have been developed. However, these tools are insufficiently accurate for producing a list of putative effectors that can be applied directly for labor-intensive experimental verification. This also suggests that important features of effectors have yet to be fully characterized. Results In this study, we have constructed an accurate approach to predicting secreted virulence effectors from Gram-negative bacteria. This consists of a support vector machine-based discriminant analysis followed by a simple criteria-based filtering. The accuracy was assessed by estimating the average number of true positives in the top-20 ranking in the genome-wide screening. In the validation, 10 sets of 20 training and 20 testing examples were randomly selected from 40 known effectors of Salmonella enterica serovar Typhimurium LT2. On average, the SVM portion of our system predicted 9.7 true positives from 20 testing examples in the top-20 of the prediction. Removal of the N-terminal instability, codon adaptation index and ProtParam indices decreased the score to 7.6, 8.9 and 7.9, respectively. These discrimination features suggested that the following characteristics of effectors had been uncovered: unstable N-terminus, non-optimal codon usage, hydrophilic, and less aliphathic. The secondary filtering process represented by coexpression analysis and domain distribution analysis further refined the average true positive counts to 12.3. We further confirmed that our system can correctly predict known effectors of P. syringae DC3000, strongly indicating its feasibility. Conclusions We have successfully developed an accurate prediction system for screening effectors on a genome-wide scale. We confirmed the accuracy of our system by external validation

Adsorption and desorption of phosphate on limestone in experiments simulating seawater intrusion

Science.gov (United States)

The absorption and desorption of phosphorus on a large block of limestone was investigated using deionized water (DIW) and seawater. The limestone had a high affinity to adsorb phosphorus in DIW. Phosphate adsorption was significantly less in seawater, and more phosphorus was desorbed in the seawate...

Radiological significance of Egyptian limestone and alabaster used for construction of dwellings

International Nuclear Information System (INIS)

El-Taher, A.; Makhluf, V.

2011-01-01

The natural radionuclides in limestone and alabaster found in Assuit Governorate in Upper Egypt have been investigated by passive gamma-ray spectrometry. From the measured γ-ray spectra, specific activities were determined. The measured activity concentrations for these natural radionuclides were compared with the reported data from other countries. The radiation hazard parameters related to the exposure of limestone and alabaster have also been calculated. The obtained results of radium equivalent Raeq, level index Iγr, the external hazard index H ex and absorbed dose rate in limestone (90.44, 0.63, 0.17, 39.94) and (70.86, 0.50, 0.13, 31.55) are lower than the acceptable level 370 Bqkg -1 for radium equivalent Ra eq , 1 for level index Iγr, the external hazard index H e≤ I and 59 (nGy.h -1 ) for absorbed dose rate. So limestone and alabaster can be used as building construction without exceeding the proposed radioactivity criterion level. (author)

Development of engineered cementitious composites with limestone powder and blast furnace slag

NARCIS (Netherlands)

Zhou, J.; Qian, S.; Sierra Beltran, M.G.; Ye, G.; Van Breugel, K.; Li, V.C.

2009-01-01

Nowadays limestone powder and blast furnace slag (BFS) are widely used in concrete as blended materials in cement. The replacement of Portland cement by limestone powder and BFS can lower the cost and enhance the greenness of concrete, since the production of these two materials needs less energy

Characterization of limestone of region South and Southeast of Para

International Nuclear Information System (INIS)

Marinho, A.R.O.; Vieira, J.H.A.; Antunes Junior, L.V.; Medeiros, A.C.; Souza, G.P.

2014-01-01

Limestone is used in daily activities, and it is common the use of products containing calcium carbonate in various applications, from construction to food production, air purification to sewage treatment, the sugar refining materials for the toothpaste, the manufacture of glass and steel in the manufacture of paper, plastics, paints, ceramics and many others. The Limestone present in the region of south and southeast of Para is presented in deposits that have not been explored on a large scale, being justified a deepening in characteristics thereof. For the characterization of the material, gross samples were comminuted by crushing and ball mill, sieved and then separated into aliquots. In the end were used fluorescence analysis of X-ray, diffraction X-rays, determination of the moisture and loss on ignition of the material at 950 °C for one hour, obtaining results of a dolomitic limestone. (author)

Are the Vinjamur rocks carbonatites or meta-limestones?

Energy Technology Data Exchange (ETDEWEB)

Subbarao, K V; Bhaskar Rao, B [Indian Institute of Technology, Bombay (India). Dept. of Earth Sciences; Le Bas, M J [Univ. of Leicester, Leicester (United Kingdom). Dept. of Geology

1995-08-01

New whole-rock rare earth element (REE) data for the metacarbonate rocks inter bedded with schists at Vinjamur in the Nellore schist belt of Andhra Pradesh, show low total REE contents ({sigma}9-128 ppm) that are inconsistent with an igneous carbonatitic origin but which correspond more closely with a sedimentary limestone origin. The REE data of these rocks however, do not give absolute discrimination between marbles of meta-limestone and metacarbonatite origin. Micro-probe analytical data give better discrimination, and the chemical compositions of the calcite, micas, amphibole, plagioclase, apatite, monazite and staurolite in the Vinjamur marbles give strong and consistent evidence of a metamorphosed sedimentary rather than an igneous origin. (author). 35 refs., 7 figs., 9 tabs.

Are the Vinjamur rocks carbonatites or meta-limestones?

International Nuclear Information System (INIS)

Subbarao, K.V.; Bhaskar Rao, B.; Le Bas, M.J.

1995-01-01

New whole-rock rare earth element (REE) data for the metacarbonate rocks inter bedded with schists at Vinjamur in the Nellore schist belt of Andhra Pradesh, show low total REE contents (σ9-128 ppm) that are inconsistent with an igneous carbonatitic origin but which correspond more closely with a sedimentary limestone origin. The REE data of these rocks however, do not give absolute discrimination between marbles of meta-limestone and metacarbonatite origin. Micro-probe analytical data give better discrimination, and the chemical compositions of the calcite, micas, amphibole, plagioclase, apatite, monazite and staurolite in the Vinjamur marbles give strong and consistent evidence of a metamorphosed sedimentary rather than an igneous origin. (author). 35 refs., 7 figs., 9 tabs

Enhancement of direct sulfation of limestone by Na{sub 2}CO{sub 3} addition

Energy Technology Data Exchange (ETDEWEB)

Chen, Chuanmin [School of Environmental Science and Engineering, North China Electric Power University, Baoding 071003, Hebei Province (China); Zhuang, Ye [Energy and Environmental Research Center, University of North Dakota, 15 North 23rd Street, Grand Forks, ND 58203 (United States); Wang, Chunbo [Department of Power engineering, North China Electric Power University, Baoding 071003, Hebei Province (China)

2009-07-15

For an oxy-fuel circulating fluidized bed combustion system, the limestone calcination is normally prevented due to excessive CO{sub 2} partial pressures and the limestone is subject to a direct sulfation reaction. The enhancement of the direct sulfation of limestone by Na{sub 2}CO{sub 3} was investigated under high CO{sub 2} partial pressure in a thermogravimetric apparatus (TGA) and scanning electron microscope (SEM) analysis method. A commercial limestone with a mean size of 18.8 {mu}m was used. Experimental results indicate that the incorporation of Na{sup +} ions in solid product CaSO{sub 4} lattice structures results in formation of more extrinsic point defects in the crystal lattices of CaSO{sub 4} and a significantly increased solid-state diffusivity/mobility in the solid product. So the direct sulfation of Na{sub 2}CO{sub 3}-doped limestone shows higher rate and higher degree of conversion in the later stage of sulfation, in comparison with the direct sulfation of original limestone. The reaction changes from diffusional control to chemical reaction control in the presence of Na{sub 2}CO{sub 3} because of the effect of foreign ions on accelerating the solid-state diffusion. (author)

Enhancement of direct sulfation of limestone by Na{sub 2}CO{sub 3} addition

Energy Technology Data Exchange (ETDEWEB)

Chuanmin Chen; Ye Zhuang; Chunbo Wang [North China Electric Power University, Baoding (China). School of Environmental Science & Engineering

2009-07-15

For an oxy-fuel circulating fluidized bed combustion system, the limestone calcination is normally prevented due to excessive CO{sub 2} partial pressures and the limestone is subject to a direct sulfation reaction. The enhancement of the direct sulfation of limestone by Na{sub 2}CO{sub 3} was investigated under high CO{sub 2} partial pressure in a thermogravimetric apparatus (TGA) and scanning electron microscope (SEM) analysis method. A commercial limestone with a mean size of 18.8 {mu}m was used. Experimental results indicate that the incorporation of Na{sup +} ions in solid product CaSO{sub 4} lattice structures results in formation of more extrinsic point defects in the crystal lattices of CaSO{sub 4} and a significantly increased solid-state diffusivity/mobility in the solid product. So the direct sulfation of Na{sub 2}CO{sub 3}-doped limestone shows higher rate and higher degree of conversion in the later stage of sulfation, in comparison with the direct sulfation of original limestone. The reaction changes from diffusional control to chemical reaction control in the presence of Na{sub 2}CO{sub 3} because of the effect of foreign ions on accelerating the solid-state diffusion. 33 refs., 7 figs., 2 tabs.

Experimental study and mechanism analysis of modified limestone by red mud for improving desulfurization

Energy Technology Data Exchange (ETDEWEB)

Liu, Hongtao; Han, Kuihua; Niu, Shengli; Lu, Chunmei; Liu, Mengqi; Li, Hui [Shandong Univ., Jinan (China). School of Energy and Power Engineering

2013-07-01

Red mud is a type of solid waste generated during alumina production from bauxite, and how to dispose and utilize red mud in a large scale is yet a question with no satisfied answer. This paper attempts to use red mud as a kind of additive to modify the limestone. The enhancement of the sulfation reaction of limestone by red mud (two kinds of Bayer process red mud and one kind of sintering process red mud) are studied by a tube furnace reactor. The calcination and sulfation process and kinetics are investigated in a thermogravimetric (TG) analyzer. The results show that red mud can effectively improve the desulfurization performance of limestone in the whole temperature range (1,073-1,373K). Sulfur capacity of limestone (means quality of SO{sub 2} which can be retained by 100mg of limestone) can be increased by 25.73, 7.17 and 15.31% while the utilization of calcium can be increased from 39.68 to 64.13%, 60.61 and 61.16% after modified by three kinds of red mud under calcium/metallic element (metallic element described here means all metallic elements which can play a catalytic effect on the sulfation process, including the Na, K, Fe, Ti) ratio being 15, at the temperature of 1,173K. The structure of limestone modified by red mud is interlaced and tridimensional which is conducive to the sulfation reaction. The phase composition analysis measured by XRD of modified limestone sulfated at high temperature shows that there are correspondingly more sulphates for silicate and aluminate complexes of calcium existing in the products. Temperature, calcium/metallic element ratio and particle diameter are important factors as for the sulfation reaction. The optimum results can be obtained as calcium/metallic element ratio being 15. Calcination characteristic of limestone modified by red mud shows a migration to lower temperature direction. The enhancement of sulfation by doping red mud is more pronounced once the product layer has been formed and consequently the promoting

Accelerated weathering of limestone for CO2 mitigation: Opportunities for the stone and cement industries

Science.gov (United States)

Langer, William H.; San, Juan A.; Rau, Greg H.; Caldeira, Ken

2009-01-01

Large amounts of limestone fines co-produced during the processing of crushed limestone may be useful in the sequestration of carbon dioxide (CO2). Accelerated weathering of limestone (AWL) is proposed as a low-tech method to capture and sequester CO2 from fossil fuel-fired power plants and other point sources such as cement manufacturing. AWL reactants are readily available, inexpensive and environmentally benign. Waste CO2 is hydrated with water to produce carbonic acid. This reacts with and is neutralized by limestone fines, thus converting CO2 gas to dissolved calcium bicarbonate.

Diversity and biogeography of land snails (Mollusca, Gastropoda) in the limestone hills of Perak, Peninsular Malaysia

Science.gov (United States)

Foon, Junn Kitt; Clements, Gopalasamy Reuben; Liew, Thor-Seng

2017-01-01

Abstract Limestone hills are now gaining global conservation attention as hotspots for short-range endemic species. Levels of land snail endemism can be high at limestone hills, especially at hill clusters that are geographically isolated. In the State of Perak, Peninsular Malaysia, limestone hills have been opportunistically surveyed for land snails in the past, but the majority have yet to be surveyed. To address this knowledge gap, we systematically surveyed the terrestrial malacofauna of 12 limestone hills that, based on our opinion, are a representation of the limestone land snail assemblages within the State. Our inventory yielded high sampling completeness (>85%). We found 122 species of land snails, of which 34 species were unique to one of the surveyed hills. We identified 30 species that are potentially new to science. The number of land snail species recorded at each hill ranged between 39 and 63 species. Four of the sampled limestone hills namely, Prk 01 G. Tempurung, Prk 55 G. Pondok, Prk 47 Kanthan, and Prk 64 Bt Kepala Gajah, have high levels of species richness and unique species, representing 91% of the total species recorded in this study. We identified two clusters of limestone hills in central Perak with distinct differences in land snail species composition – a northern hill cluster on elevated granite bedrock and southern hill cluster in a low-lying valley surrounded by alluvial soils. As limestone hills continue to be quarried to meet the cement demand, the four identified limestone hills, along with other hills from the two clusters, warrant urgent conservation attention in order to maintain high species diversity within Perak’s terrestrial malacofauna. PMID:28769723

ChIP-seq Accurately Predicts Tissue-Specific Activity of Enhancers

Energy Technology Data Exchange (ETDEWEB)

Visel, Axel; Blow, Matthew J.; Li, Zirong; Zhang, Tao; Akiyama, Jennifer A.; Holt, Amy; Plajzer-Frick, Ingrid; Shoukry, Malak; Wright, Crystal; Chen, Feng; Afzal, Veena; Ren, Bing; Rubin, Edward M.; Pennacchio, Len A.

2009-02-01

A major yet unresolved quest in decoding the human genome is the identification of the regulatory sequences that control the spatial and temporal expression of genes. Distant-acting transcriptional enhancers are particularly challenging to uncover since they are scattered amongst the vast non-coding portion of the genome. Evolutionary sequence constraint can facilitate the discovery of enhancers, but fails to predict when and where they are active in vivo. Here, we performed chromatin immunoprecipitation with the enhancer-associated protein p300, followed by massively-parallel sequencing, to map several thousand in vivo binding sites of p300 in mouse embryonic forebrain, midbrain, and limb tissue. We tested 86 of these sequences in a transgenic mouse assay, which in nearly all cases revealed reproducible enhancer activity in those tissues predicted by p300 binding. Our results indicate that in vivo mapping of p300 binding is a highly accurate means for identifying enhancers and their associated activities and suggest that such datasets will be useful to study the role of tissue-specific enhancers in human biology and disease on a genome-wide scale.

Piedramuelle Limestone in the building heritage of Oviedo, Spain, and adjacent towns.

Science.gov (United States)

Cardenes Van den Eynde, Victor; Mateos, Felix Javier; Valdeon, Luis; Rojo, Araceli

2017-04-01

The Piedramuelle limestone has a very important representation in the building heritage of Oviedo, historical capital of Asturias (Spain) and surrounding towns. This argillaceous limestone has been quarried since the High Middle Ages until the beginning of the XX century. The main mineralogical components are carbonates (mainly calcite and sometimes ankerite, 70-90%), quartz (5-15%), terrigenous minerals (6-15%) and iron oxides (blocks and ashlars of the buildings. Some of the buildings constructed with Piedramuelle limestone are the Cathedral, the Old University and the Palaces from the XVII and XVIII centuries. The ambiance and historical architecture of Oviedo and adjacent towns is closely linked with the textures and colors of this stone. Nowadays, the Piedramuelle limestone is not exploited anymore, being the quarries exhausted. This represents an issue from a conservation point of view, since there is not a suitable stone for replacement. In order to preserve and maintain the building heritage of these towns, it is very important to prospect and protect the remaining outcrops still able to supply this characteristic stone.

Porosity development in the Copper Ridge Dolomite and Maynardville Limestone, Bear Creek Valley and Chestnut Ridge, Tennessee

International Nuclear Information System (INIS)

Goldstrand, P.M.; Menefee, L.S.; Dreier, R.B.

1995-12-01

Matrix porosity data from deep core obtained in Bear Creek Valley indicate that porosities in the Maynardville Limestone are lithology and depth dependent. Matrix porosities are greater in the Cooper Ridge Dolomite than in the Maynardville Limestone, yet there is no apparent correlation with depth. Two interrelated diagenetic processes are the major controlling factors on porosity development in the Copper Ridge Dolomite and Maynardville Limestone; dissolution of evaporate minerals and dedolomitization. Both of these diagenetic processes produce matrix porosities between 2.1 and 1.3% in the Copper Ridge Dolomite and upper part of the Maynardville Limestone (Zone 6) to depths of approximately 600 ft bgs. Mean matrix porosities in Zones 5 through 2 of the Maynardville Limestone range from 0.8 to 0.5%. A large number of cavities have been intersected during drilling activities in nearly all zones of the Maynardville Limestone in Bear Creek Valley. Therefore, any maynardville Limestone zone within approximately 200 ft of the ground surface is likely to contain cavities that allow significant and rapid flow of groundwater. Zone 6 could be an important stratigraphic unit in the Maynardville Limestone for groundwater flow and contaminant transport because of the abundance of vuggy and moldic porosities. There are large variations in the thickness and lithology in the lower part of the Maynardville (Zones 2, 3, and 4 in the Burial Grounds region). The direction and velocity of strike-parallel groundwater flow may be altered in this area within the lower Maynardville Limestone

Model for the sulfidation of calcined limestone and its use in reactor models.

NARCIS (Netherlands)

Heesink, Albertus B.M.; Brilman, Derk Willem Frederik; van Swaaij, Willibrordus Petrus Maria

1998-01-01

A mathematical model describing the sulfidation of a single calcined limestone particle was developed and experimentally verified. This model, which includes no fitting parameters, assumes a calcined limestone particle to consist of spherical grains of various sizes that react with H2S according to

LATEST TOURNAISIAN (EARLY CARBONIFEROUS CONODONTS FROM THE TABAI LIMESTONE, TIRAH, NORTHWESTERN PAKISTAN

Directory of Open Access Journals (Sweden)

FAZL-I-RABBI KHAN

2004-11-01

Full Text Available A new stratigraphic unit, the Tabai Limestone of the poorly known Tirah area of northwest Pakistan, is one of several Early Carboniferous carbonate units distributed along the North Gondwana margin, some connected with transgressive interludes. The Tabai Limestone has produced latest Tournaisian (Early Carboniferous conodonts indicative of the middle of the anchoralis-latus Zone.

Accurate cut-offs for predicting endoscopic activity and mucosal healing in Crohn's disease with fecal calprotectin

Directory of Open Access Journals (Sweden)

Juan María Vázquez-Morón

Full Text Available Background: Fecal biomarkers, especially fecal calprotectin, are useful for predicting endoscopic activity in Crohn's disease; however, the cut-off point remains unclear. The aim of this paper was to analyze whether faecal calprotectin and M2 pyruvate kinase are good tools for generating highly accurate scores for the prediction of the state of endoscopic activity and mucosal healing. Methods: The simple endoscopic score for Crohn's disease and the Crohn's disease activity index was calculated for 71 patients diagnosed with Crohn's. Fecal calprotectin and M2-PK were measured by the enzyme-linked immunosorbent assay test. Results: A fecal calprotectin cut-off concentration of ≥ 170 µg/g (sensitivity 77.6%, specificity 95.5% and likelihood ratio +17.06 predicts a high probability of endoscopic activity, and a fecal calprotectin cut-off of ≤ 71 µg/g (sensitivity 95.9%, specificity 52.3% and likelihood ratio -0.08 predicts a high probability of mucosal healing. Three clinical groups were identified according to the data obtained: endoscopic activity (calprotectin ≥ 170, mucosal healing (calprotectin ≤ 71 and uncertainty (71 > calprotectin < 170, with significant differences in endoscopic values (F = 26.407, p < 0.01. Clinical activity or remission modified the probabilities of presenting endoscopic activity (100% vs 89% or mucosal healing (75% vs 87% in the diagnostic scores generated. M2-PK was insufficiently accurate to determine scores. Conclusions: The highly accurate scores for fecal calprotectin provide a useful tool for interpreting the probabilities of presenting endoscopic activity or mucosal healing, and are valuable in the specific clinical context.

Thermochemical degradation of limestone aggregate concrete on exposure to sodium fire

International Nuclear Information System (INIS)

Premila, M.; Sivasubramanian, K.; Amarendra, G.; Sundar, C.S.

2008-01-01

Limestone aggregate concrete blocks were subjected to sodium fire conforming to a realistic scenario in order to qualify them as protective sacrificial layers over structural concrete flooring in liquid metal-cooled fast breeder reactors. Mid infrared absorption measurements were carried out on these sodium fire-exposed samples as a function of depth from the affected surface. Definite signatures of thermochemical degradation indicating dehydration and structural modification of the limestone concrete have been obtained. Control runs were carried out to delineate the thermal effects of sodium fires from that of the chemical interaction effects. Measurements on limestone aggregate samples treated with fused NaOH provided direct evidence of the exact mechanism of the sodium attack on concrete. The observed degradation effects were correlated to the mechanical strength of the concrete blocks and to the intensity of the sodium fire experienced

CARBONIFEROUS CORALS AND CHAETETIDS FROM EXOTIC LIMESTONE BLOCK OF THE CRIMEA

OpenAIRE

OGAR, VICTOR; KLEVTSOVSKYI, ANDREY

2015-01-01

A chaetetid sponge and coral fauna from a Carboniferous exotic limestone block in the Lower Jurassic Esciorda olistostrome on the Bodrak River (Crimean Mountains) are described for the first time. The Bodrak exotic block is composed of massive limestone. It contains the chaetetid Chaetetes (Boswellia) sp., the tabulate coral Multithecopora sp., and poorly preserved rugose corals, including Dibunophyllum? sp., Cordibia? sp. and gen. et sp. indet. Only the fasciculate colonies of the rugose cor...

Capture of SO2 by limestone in a 71 MWe pressurized fluidized bed boiler

Directory of Open Access Journals (Sweden)

Shimizu Tadaaki

2003-01-01

Full Text Available A 71 MWe pressurized fluidized bed coal combustor was operated. A wide variety of coals were burnt under fly ash recycle conditions. Limestone was fed to the combustor as bed material as well as sorbent. The emission of SO^ and limestone attrition rate were measured. A simple mathematical model of SO? capture by limestone with intermittent solid attrition was applied to the analysis of the present experimental results. Except for high sulfur fuel, the results of the present model agreed with the experimental results.

Impacts of Limestone Multi-particle Size on Production Performance, Egg Shell Quality, and Egg Quality in Laying Hens

Directory of Open Access Journals (Sweden)

X. Y. Guo

2012-06-01

Full Text Available This experiment was conducted to evaluate the effects of single or multi-particle size limestone on the egg shell quality, egg production, egg quality and feed intake in laying hens. A total of 280 laying hens (ISA brown were used in this 10-wk trial. Laying hens were randomly assigned to 4 treatments with 14 replications per treatment and 5 adjacent cages as a replication (hens were caged individually. The experimental treatments were: i L, basal diet+10% large particle limestone; ii LS1, basal diet+8% large particle limestone+2% small particle limestone; iii LS2, basal diet+6% large particle limestone+4% small particle limestone; iv S, basal diet+10% small particle limestone. The egg production was unaffected by dietary treatments. The egg weight in S treatment was lighter than other treatments (p<0.05. The egg specific gravity in S treatment was lower than other treatments (p<0.05. The eggshell strength and eggshell thickness in S treatment were decreased when compared with other dietary treatments (p<0.05. The laying hens in LS1 and LS2 treatment had a higher average feed intake than the other two treatments (p<0.05. Collectively, the dietary multi-particle size limestone supplementation could be as efficient as large particle size limestone.

Machine learning predictions of molecular properties: Accurate many-body potentials and nonlocality in chemical space

International Nuclear Information System (INIS)

Hansen, Katja; Biegler, Franziska; Ramakrishnan, Raghunathan; Pronobis, Wiktor; Lilienfeld, O. Anatole von; Müller, Klaus-Robert; Tkatchenko, Alexandre

2015-01-01

Simultaneously accurate and efficient prediction of molecular properties throughout chemical compound space is a critical ingredient toward rational compound design in chemical and pharmaceutical industries. Aiming toward this goal, we develop and apply a systematic hierarchy of efficient empirical methods to estimate atomization and total energies of molecules. These methods range from a simple sum over atoms, to addition of bond energies, to pairwise interatomic force fields, reaching to the more sophisticated machine learning approaches that are capable of describing collective interactions between many atoms or bonds. In the case of equilibrium molecular geometries, even simple pairwise force fields demonstrate prediction accuracy comparable to benchmark energies calculated using density functional theory with hybrid exchange-correlation functionals; however, accounting for the collective many-body interactions proves to be essential for approaching the 'holy grail' of chemical accuracy of 1 kcal/mol for both equilibrium and out-of-equilibrium geometries. This remarkable accuracy is achieved by a vectorized representation of molecules (so-called Bag of Bonds model) that exhibits strong nonlocality in chemical space. The same representation allows us to predict accurate electronic properties of molecules, such as their polarizability and molecular frontier orbital energies

Nomination of the Globigerina Limestone of the Maltese Islands as a "Global Heritage Stone Resource"

Science.gov (United States)

Cassar, JoAnn

2016-04-01

The Maltese Islands consist of two main islands, Malta and Gozo, as well as a small number of islets, and lie in the central Mediterranean Sea approximately 90 km south of Sicily. Although only 316 square kilometres in size, the Islands contain a rich concentration of archaeological sites and historic buildings, as well as vernacular architecture and modern buildings, for the most part built of the local Globigerina Limestone, which is one of the few natural resources of the Islands. This stone can be described as a typical "soft limestone", very easy to carve and shape. It forms part of the large family of Oligo-Miocene "soft limestones" widely diffused in the Mediterranean Basin. The Maltese Globigerina Limestone Formation is one of five main Formations, and varies in thickness from 20 to over 200 m. The material used for building is located stratigraphically in the lower part of the Globigerina Limestone Formation, called the Lower Globigerina Limestone. This Formation is stratified into thick beds at outcrop. Sections where bioturbation is concentrated often also occur. This limestone is fine-grained, yellow to pale grey in colour, almost wholly composed of the tests of globigerinid planktonic foraminifera. Petrographically, Globigerina Limestone can be described as a bioclastic packstone, with bioclastic wackestones also occurring. This limestone has always been used as the predominant building material in the Islands. The Maltese prehistoric Temples, which were constructed approximately 6000 years ago, bear testimony to this. Between 1530 and 1798 the Order of the Knights of St John built kilometres of fortifications in this same material to protect the Island from the expanding Ottoman Empire. Fortifications, impressive churches, auberges and palaces were built of this stone during this period. The capital city of Valletta, a rich and dense manifestation of Baroque architecture in Globigerina Limestone, is included on the UNESCO World Heritage List, as are

Environmentally acceptable effect of hydrogen peroxide on cave 'lamp-flora', calcite speleothems and limestones

International Nuclear Information System (INIS)

Faimon, Jiri; Stelcl, Jindrich; Kubesova, Svatava; Zimak, Jiri

2003-01-01

Hydrogen peroxide plus limestone fragments allows removal of organisms without corrosion of limestone and speleothem. - Mosses, algae, and cyanobacteria (lamp-flora) colonize illuminated areas in show caves. This biota is commonly removed by a sodium hypochlorite solution. Because chlorine and other deleterious compounds are released into a cave environment during lamp-flora cleansing, hydrogen peroxide was tested as an alternative agent. In a multidisciplinary study conducted in the Katerinska Cave (Moravian Karst, Czech Republic), 12 algae- and cyanobacteria taxons and 19 moss taxons were detected. The threshold hydrogen peroxide concentration for the destruction of this lamp-flora was found to be 15 vol.%. Based on laboratory experiments in stirred batch reactors, the dissolution rates of limestones and calcite speleothems in water were determined as 3.77x10 -3 and 1.81x10 -3 mol m -2 h -1 , respectively. In the 15% peroxide solution, the limestone and speleothem dissolution rates were one order of magnitude higher, 2.00x10 -2 and 2.21x10 -2 mol m -2 h -1 , respectively. So, the peroxide solution was recognised to attack carbonates somewhat more aggressively than karst water. In order to prevent the potential corrosion of limestone and speleothems, the reaching of preliminary peroxide saturation with respect to calcite is recommended, for example, by adding of few limestone fragments into the solution at least 10 h prior to its application

Actinobacterial diversity in limestone deposit sites in Hundung, Manipur (India and their antimicrobial activities

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Salam eNimaichand

2015-05-01

Full Text Available Studies on actinobacterial diversity in limestone habitats are scarce. This paper reports profiling of actinobacteria isolated from Hundung limestone samples in Manipur, India using ARDRA as the molecular tool for preliminary classification. A total of 137 actinobacteria were clustered into 31 phylotypic groups based on the ARDRA pattern generated and representative of each group was subjected to 16S rRNA gene sequencing. Generic diversity of the limestone isolates consisted of Streptomyces (15 phylotypic groups, Micromonospora (4, Amycolatopsis (3, Arthrobacter (3, Kitasatospora (2, Janibacter (1, Nocardia (1, Pseudonocardia (1 and Rhodococcus (1. Considering the antimicrobial potential of these actinobacteria, 19 showed antimicrobial activities against at least one of the bacterial and candidal test pathogens, while 45 exhibit biocontrol activities against at least one of the rice fungal pathogens. Out of the 137 actinobacterial isolates, 118 were found to have at least one of the three biosynthetic gene clusters (PKS-I, PKS-II, NRPS. The results indicate that 86% of the strains isolated from Hundung limestone deposit sites possessed biosynthetic gene clusters of which 40% exhibited antimicrobial activities. It can, therefore, be concluded that limestone habitat is a promising source for search of novel secondary metabolites.

Cretaceous planktic foraminiferal biostratigraphy of the Calera Limestone, Northern California, USA

Science.gov (United States)

Sliter, W.V.

1999-01-01

The Calera Limestone is the largest, most stratigraphically extensive limestone unit of oceanic character included in the Franciscan Complex of northern California. The aim of this paper is to place the Calera Limestone at its type locality (Rockaway Beach, Pacifica) in a high-resolution biostratigraphy utilizing planktic foraminifers studied in thin section. A section, about 110 m-thick, was measured from the middle thrust slice exposed by quarrying on the southwest side of Calera Hill at Pacifica Quarry. Lithologically, the section is divided in two units; a lower unit with 73 m of black to dark-grey limestone, black chert and tuff, and an upper unit with 36.8 m of light-grey limestone and medium-grey chert. Two prominent black-shale layers rich in organic carbon occur 11 m below the top of the lower black unit and at the boundary with overlying light-grey unit, yielding a total organic content (TOC) of 4.7% and 1.8% t.w., respectively. The fossiliferous Calera Limestone section measured at Pacifica Quarry, from the lower black shale, contains eleven zones and three subzones that span approximately 26 m.y. from the early Aptian to the late Cenomanian. The zones indentified range from the Globigerinelloides blowi Zone to the Dicarinella algeriana Subzone of the Rotalipora cushmani Zone. Within this biostratigraphic interval, the Ticinella bejaouaensis and Hedbergella planispira Zones at the Aptian/Albian boundary are missing as are the Rotalipora subticinensis Subzone of the Biticinella breggiensis Zone and the overlying Rotalipora ticinensis Zone in the late Albian owing both to low-angle thrust faulting and to unconformities. The abundance and preservation of planktic foraminifers are poor in the lower part and improve only within the upper G. algerianus Zone. The faunal relationship indicate that the lower black shale occurs in the upper part of the G. blowi Zone and correlates with the Selli Event recognized at global scale in the early Aptian. The upper black

Reaction between Hydrogen Sulfide and Limestone Calcines

Czech Academy of Sciences Publication Activity Database

Hartman, Miloslav; Svoboda, Karel; Trnka, Otakar; Čermák, Jiří

2002-01-01

Roč. 41, č. 10 (2002), s. 2392-2398 ISSN 0888-5885 R&D Projects: GA AV ČR IAA4072711; GA AV ČR IAA4072801 Keywords : hydrogen sulfide * limestone calcines * desulfurization Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.247, year: 2002

Pliocene Te Aute limestones, New Zealand : expanding concepts for cool-water shelf carbonates

International Nuclear Information System (INIS)

Nelson, C.S.; Winefield, P.R.; Hood, S.D.; Caron, V.; Pallentin, A.; Kamp, P.J.J.

2003-01-01

Acceptance of a spectrum of warm- through cold-water shallow-marine carbonate facies has become of fundamental importance for correctly interpreting the origin and significance of all ancient platform limestones. Among other attributes, properties that have become a hallmark for characterising many Cenozoic non-tropical occurrences include: (1) the presence of common bryozoan and epifaunal bivalve skeletons; (2) a calcite-dominated mineralogy; (3) relatively thin deposits exhibiting low rates of sediment accumulation; (4) an overall destructive early diagenetic regime; and (5) that major porosity destruction and lithification occur mainly in response to chemical compaction of calcitic skeletons during moderate to deep burial. The Pliocene Te Aute limestones are non-tropical skeletal carbonates formed at paleolatitudes near 40-42 degrees S under the influence of commonly strong tidal flows along the margins of an actively deforming and differentially uplifting forearc basin seaway, immediately inboard of the convergent Pacific-Australian plate boundary off eastern North Island, New Zealand. This dynamic depositional and tectonic setting strongly influenced both the style and subsequent diagenetic evolution of the limestones. Some of the Te Aute limestones exhibit the above kinds of 'normal' non-tropical characteristics, but others do not. For example, many are barnacle and/or bivalve dominated, and several include attributes that at least superficially resemble properties of certain tropical carbonates. In this regard, a number of the limestones are infaunal bivalve rich and dominated by an aragonite over a calcite primary mineralogy, with consequently relatively high diagenetic potential. Individual limestone units are also often rather thick (e.g., up to 50-300 m), with accumulation rates from 0.2 to 0.5 m/ka, and locally as high as 1 m/ka. Moreover, there can be a remarkable array of diagenetic features in the limestones, involving grain alteration and

Modeling contaminant plumes in fractured limestone aquifers

DEFF Research Database (Denmark)

Mosthaf, Klaus; Brauns, Bentje; Fjordbøge, Annika Sidelmann

Determining the fate and transport of contaminant plumes from contaminated sites in limestone aquifers is important because they are a major drinking water resource. This is challenging because they are often heavily fractured and contain chert layers and nodules, resulting in a complex transport...... model. The paper concludes with recommendations on how to identify and employ suitable models to advance the conceptual understanding and as decision support tools for risk assessment and the planning of remedial actions....... behavior. Improved conceptual models are needed for this type of site. Here conceptual models are developed by combining numerical models with field data. Several types of fracture flow and transport models are available for the modeling of contaminant transport in fractured media. These include...... the established approaches of the equivalent porous medium, discrete fracture and dual continuum models. However, these modeling concepts are not well tested for contaminant plume migration in limestone geologies. Our goal was to develop and evaluate approaches for modeling the transport of dissolved contaminant...

Semiplanus (Productida, Brachiopoda) from the Carboniferous limestone of Kotaki, Niigata Prefecture, central Japan

OpenAIRE

Ibaraki, Yousuke; Sato, Kiichi

2013-01-01

An Early Carboniferous large–sized productid brachiopod species, Semiplanus semiplanus (Schwetzow, 1922), is described from the Tsuchikurazawa Limestone (upper Visean–Serpukhovian), a limestone block within a Permian accretionary complex, distributed in the Kotaki area, Itoigawa City, Niigata Prefecture, central Japan. This is the first record of Semipanus species from Japan.

Plant Guide: Limestone hawksbeard: Crepis intermedia

Science.gov (United States)

L. St. John; D. Tilley

2012-01-01

Sunflower family (Asteraceae). Limestone hawksbeard is a native perennial forb with one or two stems arising from a taproot. Plants are 30-70cm tall and basal leaves are 10-40 cm long, pinnatifid, with a fairly broad, undivided midstrip and entire or dentate segments. Plants are densely or sparsely gray-tomentulose. There are 10-60 heads per plant that are 7-12...

Degradation behavior of limestone concrete under limited time sodium exposure

International Nuclear Information System (INIS)

Das, S.K.; Sharma, A.K.; Ramesh, S.S.; Parida, F.C.; Kasinathan, N.; Chellapandi, P.

2009-01-01

Adequate safety measures are taken during design, fabrication, construction and operation of liquid sodium cooled fast breeder reactor (FBR). However, possibility of sodium leak from secondary heat transport circuits of FBR has not been completely ruled out. In the areas housing sodium pipelines such as Steam Generator Building (SGB), spilled liquid sodium not only reacts with air causing fire but also interacts with structural concrete resulting in its degradation. The structural concrete can be protected from sodium attack using sodium resistant sacrificial concrete layer or steel/refractory liners. Moreover, design and construction of sloping floor with sodium collection pit helps in minimizing the mass of sodium accumulated on the floor and exposure period. Sacrificial concrete layer on the structural concrete should meet key factors like economy, castability, easy removal of affected concrete in the event of a sodium fire and disposability of debris apart from its good resistance against hot burning sodium. Present study is directed towards testing of limestone concrete blocks (made out of 13% ordinary portland cement, 8% water, 48% coarse limestone and 31 % fine limestone aggregates)

Gamma radiation influence on Cladonia substellata (lichen) and its effects on limestone rocks

International Nuclear Information System (INIS)

Silva, Helena P. de B.; Colaco, Waldeciro; Pereira, Eugenia C.; Silva, Nicacio H. da

2009-01-01

The lichens play an important role in decomposition of the rocky substrate, through the chemical weathering of their substances. This work aimed to determine the influence of gamma Ray on usnic acid production of Cladonia substellata and the influence of chelates formation in limestone rocks. Samples with 2.5 g of C. substellata were packed on paper envelopes for irradiation submission to gamma on a Co-60 source. They received 10 different doses: 5, 7, 10, 15, 20, 30, 40, 50, 60 and 80 Gy. Lichen irradiation was conducted on the gamma irradiator (Co-60), and packed over powdered limestone. Lichen samples were analyzed by High Performance Liquid Chromatography (HPLC) and rocky samples by X-Ray Diffractometry. The X-ray diffractogram obtained from the analysis of limestone not subjected to the action of lichen - control sample was compared with limestone subjected to C. substellata irradiated at doses 10, 30 and 80Gy. Increased production of the usnic acid and changes on the rocky samples were noted. We realized that C. substellata increments the usnic acid biosynthesis as the gamma radiation dose is increased, but there is a limit to it. The chelating effect of the usnic acid on limestone was proportional to the produced amount of the substance, which could be extrapolated to natural conditions, where excessive radiation may influence pedogenesis and ecological succession. (author)

Hydration study of limestone blended cement in the presence of hazardous wastes containing Cr(VI)

International Nuclear Information System (INIS)

Trezza, M.A.; Ferraiuelo, M.F.

2003-01-01

Considering the increasing use of limestone cement manufacture, the present paper tends to characterize limestone behavior in the presence of Cr(VI). The research reported herein provides information regarding the effect of Cr(VI) from industrial wastes in the limestone cement hydration. The cementitious materials were ordinary Portland cement, as reference, and limestone blended cement. The hydration and physicomechanical properties of cementitious materials and the influence of chromium at an early age were studied with X-ray diffraction (XRD), infrared spectroscopy (FTIR), conductimetric and mechanical tests. Portland cement pastes with the addition of Cr(VI) were examined and leaching behavior with respect to water and acid solution were investigated. This study indicates that Cr(VI) modifies the rate and the components obtained during the cement hydration

DisoMCS: Accurately Predicting Protein Intrinsically Disordered Regions Using a Multi-Class Conservative Score Approach.

Directory of Open Access Journals (Sweden)

Zhiheng Wang

Full Text Available The precise prediction of protein intrinsically disordered regions, which play a crucial role in biological procedures, is a necessary prerequisite to further the understanding of the principles and mechanisms of protein function. Here, we propose a novel predictor, DisoMCS, which is a more accurate predictor of protein intrinsically disordered regions. The DisoMCS bases on an original multi-class conservative score (MCS obtained by sequence-order/disorder alignment. Initially, near-disorder regions are defined on fragments located at both the terminus of an ordered region connecting a disordered region. Then the multi-class conservative score is generated by sequence alignment against a known structure database and represented as order, near-disorder and disorder conservative scores. The MCS of each amino acid has three elements: order, near-disorder and disorder profiles. Finally, the MCS is exploited as features to identify disordered regions in sequences. DisoMCS utilizes a non-redundant data set as the training set, MCS and predicted secondary structure as features, and a conditional random field as the classification algorithm. In predicted near-disorder regions a residue is determined as an order or a disorder according to the optimized decision threshold. DisoMCS was evaluated by cross-validation, large-scale prediction, independent tests and CASP (Critical Assessment of Techniques for Protein Structure Prediction tests. All results confirmed that DisoMCS was very competitive in terms of accuracy of prediction when compared with well-established publicly available disordered region predictors. It also indicated our approach was more accurate when a query has higher homologous with the knowledge database.The DisoMCS is available at http://cal.tongji.edu.cn/disorder/.

Effect of Limestone Powder on Acid Attack Characteristics of Cement Pastes

Directory of Open Access Journals (Sweden)

Shuhua LIU

2014-12-01

Full Text Available The acid resistance of cement pastes containing limestone powder with two different water-binder (w/b ratios exposed to acetic (pH = 4 and sulfuric acid (pH = 2 solutions respectively were investigated in this paper. Limestone powder, fly ash and silica fume were also added to the cement paste mixture at different proportions. Static and flowing aqueous environments were set in this experiment. Strength and microstructure of the pastes after acid attack were investigated by using strength test, X-ray diffractometer (XRD and scanning electron microscopy (SEM. The experimental results show that the erosion degree depends not only on pH value of the solution and w/b ratio of the pastes, but also on the content of limestone powder. Acetic acid reacts with calcium hydroxide and carbonate thus dissolving the pastes, while sulfuric acid consumed calcium hydroxide, and generated gypsum and ettringite. The consumption of calcium hydroxide in the flowing solution group is higher than that in the static solution because the flowing sulfuric acid solution has negative effect upon the gypsum crystallization. Fly ash and silica fume are beneficial to limestone cement paste because of the less calcium hydroxide formation, which is among the hydrates vulnerable to acid erosion. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6231

Simple Mathematical Models Do Not Accurately Predict Early SIV Dynamics

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Cecilia Noecker

2015-03-01

Full Text Available Upon infection of a new host, human immunodeficiency virus (HIV replicates in the mucosal tissues and is generally undetectable in circulation for 1–2 weeks post-infection. Several interventions against HIV including vaccines and antiretroviral prophylaxis target virus replication at this earliest stage of infection. Mathematical models have been used to understand how HIV spreads from mucosal tissues systemically and what impact vaccination and/or antiretroviral prophylaxis has on viral eradication. Because predictions of such models have been rarely compared to experimental data, it remains unclear which processes included in these models are critical for predicting early HIV dynamics. Here we modified the “standard” mathematical model of HIV infection to include two populations of infected cells: cells that are actively producing the virus and cells that are transitioning into virus production mode. We evaluated the effects of several poorly known parameters on infection outcomes in this model and compared model predictions to experimental data on infection of non-human primates with variable doses of simian immunodifficiency virus (SIV. First, we found that the mode of virus production by infected cells (budding vs. bursting has a minimal impact on the early virus dynamics for a wide range of model parameters, as long as the parameters are constrained to provide the observed rate of SIV load increase in the blood of infected animals. Interestingly and in contrast with previous results, we found that the bursting mode of virus production generally results in a higher probability of viral extinction than the budding mode of virus production. Second, this mathematical model was not able to accurately describe the change in experimentally determined probability of host infection with increasing viral doses. Third and finally, the model was also unable to accurately explain the decline in the time to virus detection with increasing viral

Moss cushions facilitate water and nutrient supply for plant species on bare limestone pavements

DEFF Research Database (Denmark)

Jensen, Kaj Sand; Hammer, Kathrine

2012-01-01

declined by the -0.36 power of cushion diameter, and were not significantly different from -0.50 for the square root function previously predicted for the increasing thickness of the boundary layer, with greater linear dimensions for smooth flat objects at low wind velocities. Size dependence vanished...... richness, and evaluated duration of plant activity during desiccation as a function of ground area, for a large collection of moss cushions. We found that lower evaporation and higher water storage contributed equally to extending the desiccation period with increasing cushion size. Evaporation rates......Dense moss cushions of different size are distributed across the bare limestone pavements on Øland, SE Sweden. Increasing cushion size is predicted to physically protect and improve performance and colonization by vascular plants. Therefore, we tested water balance, phosphorus supply, and species...

Improving medical decisions for incapacitated persons: does focusing on "accurate predictions" lead to an inaccurate picture?

Science.gov (United States)

Kim, Scott Y H

2014-04-01

The Patient Preference Predictor (PPP) proposal places a high priority on the accuracy of predicting patients' preferences and finds the performance of surrogates inadequate. However, the quest to develop a highly accurate, individualized statistical model has significant obstacles. First, it will be impossible to validate the PPP beyond the limit imposed by 60%-80% reliability of people's preferences for future medical decisions--a figure no better than the known average accuracy of surrogates. Second, evidence supports the view that a sizable minority of persons may not even have preferences to predict. Third, many, perhaps most, people express their autonomy just as much by entrusting their loved ones to exercise their judgment than by desiring to specifically control future decisions. Surrogate decision making faces none of these issues and, in fact, it may be more efficient, accurate, and authoritative than is commonly assumed.

Properies of binder systems containing cement, fly ash, and limestone powder

Directory of Open Access Journals (Sweden)

Krittiya Kaewmanee

2014-10-01

Full Text Available Fly ash and limestone powder are two major widely available cement replacing materials in Thailand. However, the current utilization of these materials is still not optimized due to limited information on properties of multi-binder systems. This paper reports on the mechanical and durability properties of mixtures containing cement, fly ash, and limestone powder as single, binary, and ternary binder systems. The results showed that a single binder system consisting of only cement gave the best carbonation resistance. A binary binder system with fly ash exhibited superior performances in long-term compressive strength and many durability properties except carbonation and magnesium sulfate resistances, while early compressive strength of a binary binder system with limestone powder was excellent. The ternary binder system, taking the most benefit of selective cement replacing materials, yielded, though not the best, satisfactory performances in almost all properties. Thus, the optimization of binders can be achieved through a multi-binder system.

Fault architecture and growth in clay-limestone alternations: insights from field observations in the SE Basin, France

International Nuclear Information System (INIS)

Rocher, M.; Roche, V.; Homberg, C.

2012-01-01

Document available in extended abstract form only. The Callovo-Oxfordian (COX) clayey formation is currently studied by Andra in 'Meuse/Haute- Marne' (MHM), eastern Paris basin (France), for hosting a disposal of high level and intermediate, long-lived radioactive waste. As an independent organisation performing safety reviews for the Nuclear Safety Authority, IRSN conducts studies in support of the review of this disposal project. This nearly 130 m-thick clayey formation is surrounded by two 250 m-thick limestone formations. In such limestone/clay alternations, tectonic fracturing is often observed within limestones and propagates in some cases to clay layers. Such a propagation through the COX within or close to the disposal area could diminish its containment ability by creating preferential pathways of radioactive solute towards limestones. Nevertheless, minor to moderate fracturing is difficult to investigate in hectometre scale multilayer systems such as COX: seismic reflexion surveys only provide data on major faults, drilling data are too localised and clays have a 'bad-land' aspect at surface. The aim of this study is to provide a model of fracturing across clay-limestone alternations so as to strengthen the assessment of their possible development. We thus investigated fracturing within decametre-sized clay-limestone alternations, located in the South-Eastern Basin (France), to determine the evolution of fault architecture during its growth. After analysis of the possible scale effects using data from other analogous fields, an application to the COX in MHM is presented. We studied minor normal faults that reflect various stages of development, from simple fault planes restricted to limestones to complex fault zones propagated across several clay-limestone layers. The analysis of the fault characteristics, the construction of displacement profiles and the results obtained using numerical models enlighten fault growth processes, i.e. nucleation

The MIDAS touch for Accurately Predicting the Stress-Strain Behavior of Tantalum

Energy Technology Data Exchange (ETDEWEB)

Jorgensen, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-03-02

Testing the behavior of metals in extreme environments is not always feasible, so material scientists use models to try and predict the behavior. To achieve accurate results it is necessary to use the appropriate model and material-specific parameters. This research evaluated the performance of six material models available in the MIDAS database [1] to determine at which temperatures and strain-rates they perform best, and to determine to which experimental data their parameters were optimized. Additionally, parameters were optimized for the Johnson-Cook model using experimental data from Lassila et al [2].

Reclamation of acidic colliery spoil. III. Problems associated with the use of high rates of limestone

Energy Technology Data Exchange (ETDEWEB)

Costigan, P A [Univ. of Liverpool, England; Bradshaw, A D; Gemmell, R P

1982-04-01

Growth of Trifolium repens in acidic colliery spoil was suppressed by more than 90% when agricultural ground calcitic limestone was applied at above 5 t ha/sup -1/ whereas Lolium perenne was unaffected at rates up to 100 t ha/sup -1/. The inhibitory effect of ground limestone on T. repens was reduced by high phosphorus fertilization and disappeared within 34 weeks of treatment.There was some evidence that high liming caused an imbalance of the Ca/Mg ratio in freshly limed spoil, contribution to growth inhibition. Growth of L. perene was improved and the inhibitory effect on T. repens was alleviated by substituting magnesian limestone (dolomite) for calcitic limestone. Phosphate adsorption of spoil was similar after low and very high limestone applications but increased by 100% after liming at 25 t ha/sup -1/ to pH 5.1.It is suggested that phosphate adsorption at pH 5.1 is caused by freshly precipitated amorphous aluminium hydroxide. The practical implications of the results are discussed.

The Öland limestone - A Swedish stone used for more than one thousand years

Science.gov (United States)

Schouenborg, Björn; Wickström, Linda; Mikaelsson, Jan

2016-04-01

The second largest island in Sweden is the home of the "Öland limestone", a condensed and bedded limestone whose origin dates back to Lower Ordovician, i.e. about 480 M years ago. Öland is a part of the palaeocontinent Baltica that, at the time, was situated at low latitudes with deposition of the calcareous sediments in a cool water environment. The limestone on Öland represents a proximal ramp tectonic setting, with the oldest sediments deposited in the west and younger sediments deposited towards east and southeast. Fluctuating sea-levels have created erosional hard grounds such as the Flowery sheet. These hardgrounds are recognised by their vivid colours and trace fossils, and can be traced all over Baltica, but is maybe best represented on Öland. Ordovician limestones are present in many places in Sweden, but it is the occurrence on Öland that is the most renowned in a building stone perspective. One reason for this is the favourable trading location, an island off the Swedish East coast in middle of the trading routes between the Baltic countries and the continent. Other reasons are the pleasant aesthetical values with numerous orthoceratites and other fossils. The limestones on Öland differ in colour. From the red varieties (with oxidized iron) to brownish and grey. The bedding is mostly in the cm-scale which easily enables very exploitable thickness of slabs. Every mm limestone represents about 1000 years of deposition. The limestone has most likely been used in a very crude way for many thousand years, but archaeological evidence of a more industrialized usage is just a little more than 1000 years. It is known from the literature that the first official Swedish king, Gustav Vasa (16th century), desired this stone. At the time it was called "Öland marble", and the king "imported" specialists to process it further at the Royal Stone workshop on northern Öland. Remnants of tools and working sites still remain in an outdoor museum. Export of the �

A highly accurate predictive-adaptive method for lithium-ion battery remaining discharge energy prediction in electric vehicle applications

International Nuclear Information System (INIS)

Liu, Guangming; Ouyang, Minggao; Lu, Languang; Li, Jianqiu; Hua, Jianfeng

2015-01-01

Highlights: • An energy prediction (EP) method is introduced for battery E RDE determination. • EP determines E RDE through coupled prediction of future states, parameters, and output. • The PAEP combines parameter adaptation and prediction to update model parameters. • The PAEP provides improved E RDE accuracy compared with DC and other EP methods. - Abstract: In order to estimate the remaining driving range (RDR) in electric vehicles, the remaining discharge energy (E RDE ) of the applied battery system needs to be precisely predicted. Strongly affected by the load profiles, the available E RDE varies largely in real-world applications and requires specific determination. However, the commonly-used direct calculation (DC) method might result in certain energy prediction errors by relating the E RDE directly to the current state of charge (SOC). To enhance the E RDE accuracy, this paper presents a battery energy prediction (EP) method based on the predictive control theory, in which a coupled prediction of future battery state variation, battery model parameter change, and voltage response, is implemented on the E RDE prediction horizon, and the E RDE is subsequently accumulated and real-timely optimized. Three EP approaches with different model parameter updating routes are introduced, and the predictive-adaptive energy prediction (PAEP) method combining the real-time parameter identification and the future parameter prediction offers the best potential. Based on a large-format lithium-ion battery, the performance of different E RDE calculation methods is compared under various dynamic profiles. Results imply that the EP methods provide much better accuracy than the traditional DC method, and the PAEP could reduce the E RDE error by more than 90% and guarantee the relative energy prediction error under 2%, proving as a proper choice in online E RDE prediction. The correlation of SOC estimation and E RDE calculation is then discussed to illustrate the

Effect of SO2 Dry Deposition on Porous Dolomitic Limestones

Directory of Open Access Journals (Sweden)

Florica Doroftei

2010-01-01

Full Text Available The present study is concerned with the assessment of the relative resistance of a monumental dolomitic limestone (Laspra – Spain used as building material in stone monuments and submitted to artificial ageing by SO2 dry deposition in the presence of humidity. To investigate the protection efficiency of different polymeric coatings, three commercially available siloxane-based oligomers (Lotexan-N, Silres BS 290 and Tegosivin HL 100 and a newly synthesized hybrid nanocomposite with silsesquioxane units (TMSPMA were used. A comparative assessment of the data obtained in this study underlines that a better limestone protection was obtained when treated with the hybrid nanocomposite with silsesquioxane units.

Induration and Biot’s Coefficient of Palaeogene Limestone

DEFF Research Database (Denmark)

Andreassen, Katrine Alling

2017-01-01

In engineering geology and classification of rock masses for civil engineering purposes, the degree of induration for a rock serves as a useful classification parameter. Induration is a measure of how well the grains of a sedimentary rock are cemented together - from loosely cemented/soft rock...... to very competent/slightly metamorphic rock. The Biot coefficient links to the degree of cementation in the capacity of how it relates the elastic deformations with the change in pore pressure. A hypothesis is that the degree of induration could be correlated to the magnitude of the Biot coefficient....... This is tested on 11 Copenhagen Limestone specimens of varying porosity and densities obtained from one borehole with a limestone interval of 30 m. Their induration varies from H2 to H5. Elastic wave propagation measurements are used to establish the Biot coefficient and determination of the mineralogy for H5...

Paleomagnetism of Cretaceous limestones from western Tarim basin suggests negligible latitudinal offset yet significant clockwise rotation

Science.gov (United States)

Tan, X.; Gilder, S.; Chen, Y.; Cogné, J. P.; Courtillot, V. E.; Cai, J.

2017-12-01

Large northward translation of central Asian crustal blocks has been reported from paleomagnetism of Cretaceous and Tertiary terrestrial sediments. This motion was initially taken as evidence of deformation occurred in the Asian interior as a result of indentation of the Indian Plate. However, because the amount of motion is far greater than geological observations, accuracy of the paleomagnetic record has become a controversial issue. To solve the problem, it has been shown that the latitudinal offset can be entirely attributed to inclination shallowing during deposition and compaction processes (Tan et al., 2003; Tauxe and Kent, 2004). On the other hand, coeval volcanic rocks from central Asia did record steeper paleomagnetic inclinations than terrestrial rocks (Gilder et al., 2003). To extend the effort of solving the controversy, we report paleomagnetic results of Cretaceous limestones from western Tarim basin. Our results show that the majority of our collections have been overprinted. Fortunately, a special type of limestones preserved stable characteristic remanence. Fold tests suggest a primary origin of the magnetization. Comparison of the paleomagnetic direction with the coeval expected direction from reference poles indicates a negligible amount of northward movement consistent with previous result of inclination correction based on magnetic fabrics, and a pattern of clockwise rotation symmetric with the style observed in the western flank of the Pamir ranges. Rock magnetic data will also be presented to support the accurate paleomagnetic record.

Reduction of SO sub 2 emission from a fluidized-bed under staged combustion by coarse limestone

International Nuclear Information System (INIS)

Khan, W.Z.; Gibbbs, B.M.

1998-01-01

A study was performed to investigate the effect of course limestone on the reduction of SO sub 2 emission from a fluidized-bed under staged combustion. The limestone of 1.2-2.5 mm size was premixed with fine coal of 1-3 mm size and fed under bed. The staging levels, bed height, and Ca/S ratio was fixed at 70:30, 30 cm and 3:1, respectively. A maximum of around 50% reduction in SO sub 2 emissions was achieved at both excess air of 20 and 40% and at 830 deg. C. bed temperature. The SO sub 2 emissions were very sensitive to bed temperature. The course limestone was found better in desulfurization efficiency at lower temperature than fine limestone. (author)

Do dual-route models accurately predict reading and spelling performance in individuals with acquired alexia and agraphia?

Science.gov (United States)

Rapcsak, Steven Z; Henry, Maya L; Teague, Sommer L; Carnahan, Susan D; Beeson, Pélagie M

2007-06-18

Coltheart and co-workers [Castles, A., Bates, T. C., & Coltheart, M. (2006). John Marshall and the developmental dyslexias. Aphasiology, 20, 871-892; Coltheart, M., Rastle, K., Perry, C., Langdon, R., & Ziegler, J. (2001). DRC: A dual route cascaded model of visual word recognition and reading aloud. Psychological Review, 108, 204-256] have demonstrated that an equation derived from dual-route theory accurately predicts reading performance in young normal readers and in children with reading impairment due to developmental dyslexia or stroke. In this paper, we present evidence that the dual-route equation and a related multiple regression model also accurately predict both reading and spelling performance in adult neurological patients with acquired alexia and agraphia. These findings provide empirical support for dual-route theories of written language processing.

Volume change of limestone and its effects on drying shrinkage of concrete

OpenAIRE

YAGI, Shogo; AQUINO, Carlos; INOUE, Masumi; OKAMOTO, Takahisa

2010-01-01

Recently, the cracks of concrete by drying shrinkage become one of the problems in the construction industry in Japan. The drying shrinkage decreases when the concrete is produced with limestone aggregate. However, it is not clear why the drying shrinkage is decreased. The purpose of this study is to clarify the relation between the drying shrinkage of concrete and the limestone aggregate. In this study, the experiments about the strength, elasticity and drying shrinkage of concrete and the p...

Hydration of Blended Portland Cements Containing Calcium-Aluminosilicate Glass Powder and Limestone

DEFF Research Database (Denmark)

Moesgaard, M; Poulsen, Søren Lundsted; Herfort, D

2012-01-01

M. MOESGAARD, S.L. POULSEN, D. HERFORT, M. STEENBERG, L.F. KIRKEGAARD, J. SKIBSTED, Y. YUE, Hydration of Blended Portland Cements Containing Calcium-Aluminosilicate Glass Powder and Limestone, Journal of the American Ceramic Society 95, 403 – 409 (2012).......M. MOESGAARD, S.L. POULSEN, D. HERFORT, M. STEENBERG, L.F. KIRKEGAARD, J. SKIBSTED, Y. YUE, Hydration of Blended Portland Cements Containing Calcium-Aluminosilicate Glass Powder and Limestone, Journal of the American Ceramic Society 95, 403 – 409 (2012)....

Effects of dietary calcium levels and limestone particicle size on the performance, tibia and blood of laying hens

Directory of Open Access Journals (Sweden)

K Pelicia

2011-03-01

Full Text Available A total of 405 23-week-old ISA® Brown layers were distributed in a completely randomized experimental design in a factorial arrangement with nine treatments consisting of three dietary calcium levels (3.5, 3.75, and 4.5% and three limestone particle sizes (100% fine limestone (FL, 70% FL + 30% coarse limestone (CL and 50% (FL + 50% (CL, with nine replicates of five birds per cage. The following parameters were evaluated: percentage of lay, defective eggs, egg weight, egg mass, feed intake, feed conversion ratio (per kg eggs and per dozen eggs, and mortality. Dietary Ca levels significantly affected lay, with birds fed diets containing 4.5% calcium producing less eggs as compared to those fed 3.0 and 3.75% Ca. Egg production linearly decreased as dietary Ca levels increased, but blood Ca levels (mg/L increased in 28-week-old birds. The interaction of dietary Ca levels and limestone particle sizes resulted in a reduction in tibial ash Ca content as dietary Ca levels increased and as fine limestone was replaced by coarse limestone. It is concluded that a dietary Ca level of 3.75% and 100% fine particle limestone are required to maintain adequate egg production and available Ca blood level.

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...

Carbonate Minerals with Magnesium in Triassic Terebratula Limestone in the Term of Limestone with Magnesium Application as a Sorbent in Desulfurization of Flue Gases

Science.gov (United States)

Stanienda-Pilecki, Katarzyna

2017-09-01

This article presents the results of studies of Triassic (Muschelkalk) carbonate rock samples of the Terebratula Beds taken from the area of the Polish part of the Germanic Basin. It is the area of Opole Silesia. The rocks were studied in the term of possibility of limestone with magnesium application in desulfurization of flue gases executed in power plants. Characteristic features of especially carbonate phases including magnesium-low-Mg calcite, high-Mg calcite, dolomite and huntite were presented in the article. They were studied to show that the presence of carbonate phases with magnesium, especially high-Mg calcite makes the desulfurization process more effective. Selected rock samples were examined using a microscope with polarized, transmitted light, X-ray diffraction, microprobe measurements and FTIR spectroscopy. The results of studies show a domination of low magnesium calcite in the limestones of the Terebratula Beds. In some samples dolomite and lower amounts of high-Mg calcite occurred. Moreover, huntite was identified. The studies were very important, because carbonate phases like high-Mg calcite and huntite which occurred in rocks of the Triassic Terebratula Beds were not investigated in details by other scientists but they presence in limestone sorbent could influence the effectiveness of desulfurization process.

Dynamic responses of photosystem II in the Namib Desert shrub, Zygophyllum prismatocarpum, during and after foliar deposition of limestone dust

International Nuclear Information System (INIS)

Heerden, P.D.R. van; Krueger, G.H.J.; Kilbourn Louw, M.

2007-01-01

The effects of limestone dust deposition on vegetation in desert ecosystems have not yet been reported. We investigated these effects in a succulent shrub from the Namib Desert at a limestone quarry near Skorpion Zinc mine (Namibia). Effects of limestone dust were determined in Zygophyllum prismatocarpum (dollar bush) plants with heavy, moderate and no visible foliar dust cover by means of chlorophyll a fluorescence measurements. Limestone dust deposition decreased overall plant performance through loss of chlorophyll content, inhibition of CO 2 assimilation, uncoupling of the oxygen-evolving complex and decreased electron transport. Importantly, dynamic recovery occurred after termination of limestone extraction at the quarry. Recovery was accelerated by rainfall, mainly because of dust removal from leaves and stimulation of new growth. These results indicate that limestone dust has severe effects on photosynthesis in desert shrubs, but that recovery is possible and that, in arid environments, this process is modulated by rainfall. - Limestone dust deposition reduced photosynthetic capacity in the Namib Desert shrub, Zygophyllum prismatocarpum

Sedimentary and environmental history of the Late Permian Bonikowo Reef (Zechstein Limestone, Wuchiapingian, western Poland

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Paweł Raczyński

2017-07-01

Full Text Available The Bonikowo Reef occurs in the central part of the Zechstein Limestone Basin in western Poland and was growing on the topmost edges of tilted blocks and/or on the top of uplifted horsts of the Brandenburg–Wolsztyn–Pogorzela High. Its size is ca. 1.6 km2. The Bonikowo Reef shows the thickest reef section (90.5 m recorded in the High. The Zechstein Limestone unit is represented mostly by limestones, often thoroughly recrystallized, although the macrotextures and biota of the boundstone are identifiable in most cases. The drillcore section is a mixture of boundstones (microbial and bryozoan, wackestones, packstones and grainstones, which often co-occur. The δ13C and δ18O values for both calcite (avg. 3.8 ± 0.8‰ and −3.4 ± 1.7‰, respectively and dolomite (avg. 3.5 ± 0.7‰ and −5.2 ± 1.3‰, respectively are transitional between the values previously reported for condensed sequences of the basinal facies and larger reef complexes. The biofacies of the Bonikowo Reef are very similar to those recognized in other reefs of the Brandenburg–Wolsztyn–Pogorzela High, which owe their origin to the destruction of bryozoan boundstones. The biota composition is typical and characteristic of other Zechstein Limestone reefs. However, the Bonikowo Reef demonstrates the importance of microbialites, laminar and nodose encrustations, in the growth and cohesion of the Zechstein Limestone reefs. Such encrustations abound within the Zechstein Limestone although, in many cases, the real nature of the encrustations is difficult to ascertain. These laminated encrustations show great similarity to Archaeolithoporella that is one of the most important Permian reef-building organisms. The encrustations considered to represent Archaeolithoporella were also previously recorded in the Zechstein Limestone of western Poland and in its stratigraphic equivalent, the Middle Magnesian Limestone of Northeast England. The lower part of the sequence shows

Nitrogen utilization and digestibility of amino acids by lambs fed a high-concentrate diet with limestone or magnesium oxide.

Science.gov (United States)

Christiansen, M L; Webb, K E

1990-07-01

Effects were evaluated of high dietary levels of magnesium oxide (MgO) or limestone on DM, OM and CP digestibility, N balance and intestinal absorption of amino acids by lambs fed a high concentrate diet. Twelve wether lambs equipped with abomasal and ileal cannulas were blocked by weight and breeding and allotted to treatments in a randomized block design in two consecutive trials. Diets were control (800 g), control plus 1.5% MgO (812 g), control plus 1.5% limestone (812 g) and control plus 3.0% limestone (824 g) fed in two equal portions at 12-h intervals. Ruminal fluid pH differences were small. The pH of ileal digesta was greater (P less than .05) with MgO than with limestone (8.23 vs 7.73). Fecal pH was higher (P less than .01) for lambs fed all mineral treatments (avg 8.75) than for lambs fed the control (7.61) and was higher (P less than .01) when MgO (9.53) rather than limestone (8.36) was fed. Ruminal NH3N was lower (P less than .01) when lambs were fed MgO (11.9 mg/dl) compared with limestone (avg 31.2 mg/dl). Preintestinal DM digestibility was greatest (P less than .10) with limestone (avg 49.5%) feeding compared with feeding MgO (31.2%) or the control (35.4%). About 41.5% more essential (P less than .05) and 48% more nonessential (P less than .03) amino acids reached the small intestine when MgO was fed than when limestone was fed. Partial digestibility of amino acids in the small intestine was reduced (P less than .03) an average of 5 percentage units when MgO or limestone was fed. Feeding high levels of MgO or limestone to lambs did not improve the overall digestibility of DM, OM or CP. In fact, feeding high levels of MgO or limestone appeared to be detrimental, reducing intestinal absorption of amino acids.

Interpretation of well hydrographs in the karstic Maynardville Limestone at the Oak Ridge Y-12 Plant

International Nuclear Information System (INIS)

Shevenell, L.A.; McMaster, B.W.

1996-06-01

The Maynardville Limestone in Oak Ridge, Tennessee underlies the southern portion of Bear Creek Valley (BCV), and is considered to be the primary pathway for groundwater leaving the Y-12 Plant boundaries. Sixty-seven percent of all wells drilled into the Maynardville Limestone have intersected at least one cavity, suggesting karst features may be encountered throughout the shallow (< 200 ft) portions of the Limestone. Because waste facilities at the Y-12 Plant are located adjacent to the Maynardville Limestone, contaminants could enter the karst aquifer and be transported in the conduit system. As part of an overall hydrologic characterization effort of this karst aquifer, 41 wells in the Maynardville Limestone were instrumented with pressure transducers to monitor water level changes (hydrographs) associated with rain events. Wells at depths between approximately 20 and 750 ft were monitored over the course of at least two storms in order that variations with depth could be identified. The wells selected were not exclusively completed in cavities but were selected to include the broad range of hydrologic conditions present in the Maynardville Limestone. Cavities, fractures and diffuse flow zones were measured at a variety of depths. The water level data from the storms are used to identify areas of quickflow versus slower flowing water zones. The data are also used to estimate specific yields and continuum transmissitives in different portions of the aquifer

Influence of limestone waste as partial replacement material for sand and marble powder in concrete properties

Directory of Open Access Journals (Sweden)

Omar M. Omar

2012-12-01

Full Text Available Green concrete are generally composed of recycling materials as hundred or partial percent substitutes for aggregate, cement, and admixture in concrete. Limestone waste is obtained as a by-product during the production of aggregates through the crushing process of rocks in rubble crusher units. Using quarry waste as a substitute of sand in construction materials would resolve the environmental problems caused by the large-scale depletion of the natural sources of river and mining sands. This paper reports the experimental study undertaken to investigate the influence of partial replacement of sand with limestone waste (LSW, with marble powder (M.P as an additive on the concrete properties. The replacement proportion of sand with limestone waste, 25%, 50%, and 75% were practiced in the concrete mixes except in the concrete mix. Besides, proportions of 5%, 10% and 15% marble powder were practiced in the concrete mixes. The effects of limestone waste as fine aggregate on several fresh and hardened properties of the concretes were investigated. The investigation included testing of compressive strength, indirect tensile strength, flexural strength, modulus of elasticity, and permeability. It was found that limestone waste as fine aggregate enhanced the slump test of the fresh concretes. But the unit weight concretes were not affected. However, the good performance was observed when limestone waste as fine aggregate was used in presence of marble powder.

ILT based defect simulation of inspection images accurately predicts mask defect printability on wafer

Science.gov (United States)

Deep, Prakash; Paninjath, Sankaranarayanan; Pereira, Mark; Buck, Peter

2016-05-01

At advanced technology nodes mask complexity has been increased because of large-scale use of resolution enhancement technologies (RET) which includes Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO). The number of defects detected during inspection of such mask increased drastically and differentiation of critical and non-critical defects are more challenging, complex and time consuming. Because of significant defectivity of EUVL masks and non-availability of actinic inspection, it is important and also challenging to predict the criticality of defects for printability on wafer. This is one of the significant barriers for the adoption of EUVL for semiconductor manufacturing. Techniques to decide criticality of defects from images captured using non actinic inspection images is desired till actinic inspection is not available. High resolution inspection of photomask images detects many defects which are used for process and mask qualification. Repairing all defects is not practical and probably not required, however it's imperative to know which defects are severe enough to impact wafer before repair. Additionally, wafer printability check is always desired after repairing a defect. AIMSTM review is the industry standard for this, however doing AIMSTM review for all defects is expensive and very time consuming. Fast, accurate and an economical mechanism is desired which can predict defect printability on wafer accurately and quickly from images captured using high resolution inspection machine. Predicting defect printability from such images is challenging due to the fact that the high resolution images do not correlate with actual mask contours. The challenge is increased due to use of different optical condition during inspection other than actual scanner condition, and defects found in such images do not have correlation with actual impact on wafer. Our automated defect simulation tool predicts

Groundwater monitoring of an open-pit limestone quarry: groundwater characteristics, evolution and their connections to rock slopes.

Science.gov (United States)

Eang, Khy Eam; Igarashi, Toshifumi; Fujinaga, Ryota; Kondo, Megumi; Tabelin, Carlito Baltazar

2018-03-06

Groundwater flow and its geochemical evolution in mines are important not only in the study of contaminant migration but also in the effective planning of excavation. The effects of groundwater on the stability of rock slopes and other mine constructions especially in limestone quarries are crucial because calcite, the major mineral component of limestone, is moderately soluble in water. In this study, evolution of groundwater in a limestone quarry located in Chichibu city was monitored to understand the geochemical processes occurring within the rock strata of the quarry and changes in the chemistry of groundwater, which suggests zones of deformations that may affect the stability of rock slopes. There are three distinct geological formations in the quarry: limestone layer, interbedded layer of limestone and slaty greenstone, and slaty greenstone layer as basement rock. Although the hydrochemical facies of all groundwater samples were Ca-HCO 3 type water, changes in the geochemical properties of groundwater from the three geological formations were observed. In particular, significant changes in the chemical properties of several groundwater samples along the interbedded layer were observed, which could be attributed to the mixing of groundwater from the limestone and slaty greenstone layers. On the rainy day, the concentrations of Ca 2+ and HCO 3 - in the groundwater fluctuated notably, and the groundwater flowing along the interbedded layer was dominated by groundwater from the limestone layer. These suggest that groundwater along the interbedded layer may affect the stability of rock slopes.

Prognostic breast cancer signature identified from 3D culture model accurately predicts clinical outcome across independent datasets

Energy Technology Data Exchange (ETDEWEB)

Martin, Katherine J.; Patrick, Denis R.; Bissell, Mina J.; Fournier, Marcia V.

2008-10-20

One of the major tenets in breast cancer research is that early detection is vital for patient survival by increasing treatment options. To that end, we have previously used a novel unsupervised approach to identify a set of genes whose expression predicts prognosis of breast cancer patients. The predictive genes were selected in a well-defined three dimensional (3D) cell culture model of non-malignant human mammary epithelial cell morphogenesis as down-regulated during breast epithelial cell acinar formation and cell cycle arrest. Here we examine the ability of this gene signature (3D-signature) to predict prognosis in three independent breast cancer microarray datasets having 295, 286, and 118 samples, respectively. Our results show that the 3D-signature accurately predicts prognosis in three unrelated patient datasets. At 10 years, the probability of positive outcome was 52, 51, and 47 percent in the group with a poor-prognosis signature and 91, 75, and 71 percent in the group with a good-prognosis signature for the three datasets, respectively (Kaplan-Meier survival analysis, p<0.05). Hazard ratios for poor outcome were 5.5 (95% CI 3.0 to 12.2, p<0.0001), 2.4 (95% CI 1.6 to 3.6, p<0.0001) and 1.9 (95% CI 1.1 to 3.2, p = 0.016) and remained significant for the two larger datasets when corrected for estrogen receptor (ER) status. Hence the 3D-signature accurately predicts breast cancer outcome in both ER-positive and ER-negative tumors, though individual genes differed in their prognostic ability in the two subtypes. Genes that were prognostic in ER+ patients are AURKA, CEP55, RRM2, EPHA2, FGFBP1, and VRK1, while genes prognostic in ER patients include ACTB, FOXM1 and SERPINE2 (Kaplan-Meier p<0.05). Multivariable Cox regression analysis in the largest dataset showed that the 3D-signature was a strong independent factor in predicting breast cancer outcome. The 3D-signature accurately predicts breast cancer outcome across multiple datasets and holds prognostic

Optimization of nanolime solvent for the consolidation of coarse porous limestone

Science.gov (United States)

Borsoi, Giovanni; Lubelli, Barbara; van Hees, Rob; Veiga, Rosário; Silva, António Santos

2016-09-01

The potentialities of nanomaterials for application in the field of conservation have been widely investigated in the last two decades. Among nanomaterials, nanolimes, i.e., dispersions of lime nanoparticles in alcohols are promising consolidating products for calcareous materials. Nanolimes are effective in recovering the very superficial loss of cohesion of decayed materials, but they do not always provide sufficient mass consolidation. This limitation is mainly related to the deposition of the nanoparticles nearby the surface of the material. Experimental research has been set up with the aim of improving the in-depth deposition of lime nanoparticles. Previous research by the authors has shown that nanolime deposition within a substrate can be controlled by adapting the nanolimes properties (kinetic stability and evaporation rate) to the moisture transport behavior of the substrate. Nanolime properties can be modified by the use of different solvents. In this research, nanolime dispersions have been further optimized for application on Maastricht limestone, a coarse porous limestone. Firstly, nanolimes were synthesized and dispersed in ethanol and/or water, both pure and mixed in different percentages. Subsequently, based on the kinetic stability of the nanolime dispersions, the most promising solvent mixtures were selected and applied on the limestone. The deposition of lime nanoparticles within the limestone was studied by phenolphthalein test, optical microscopy and scanning electron microscopy. The results confirm that nanolime dispersed in a mixture of ethanol (95 %) and water (5 %) can guarantee a better nanoparticles in-depth deposition within coarse porous substrates, when compared to dispersions in pure ethanol.

Ruminal degradation of dry matter and neutral detergent fiber of banana peel treated with limestone

Directory of Open Access Journals (Sweden)

Flávio Pinto Monção

2016-02-01

Full Text Available This study aimed to evaluate the kinetics of dry matter degradation and neutral detergent fiber of banana peel treated with limestone. The banana peel has been acquired from a candy manufacturer that after washing with chlorinated water to 1% and pulp removal was discarded. The banana peel in nature was treated with 1, 2, 3 and 4% of limestone in the natural matter, homogenized and pre-dried in the sun for 120 hours. The experiment was conducted in a completely randomized experimental design, with five treatments (0 (control, 1, 2, 3 and 4% inclusion of limestone with 3 repetitions. The dry matter potential degradability, showed no difference (P>0.05 in the levels compared to the control with an average of 67.58%. The insoluble degradation fraction rate of dry matter and the fiber fraction did not differ (P> 0.05 between levels and control. In relation to effective degradability of neutral detergent fiber, there was an increase of 3.47% for each percentage unit increased limestone. In relation to the ruminal degradation parameters of dry matter and neutral detergent fiber is not recommended the utilization of limestone as an additive in the treatment of banana peel.

High Resolution Hydraulic Profiling and Groundwater Sampling using FLUTe™ System in a Fractured Limestone Setting

DEFF Research Database (Denmark)

Janniche, Gry Sander; Christensen, Anders G.; Grosen, Bernt

challeng-ing in deposit types as fractured limestone. The activities of a bulk distribution facility for perchloroe-thene (PCE) and trichloroethene (TCE) at the Naverland site near Copenhagen, Denmark, has resulted in PCE and TCE DNAPL impacts to a fractured clay till and an underlying fractured limestone...

STEAM ENHANCED REMEDIATION RESEARCH FOR DNAPL IN FRACTURED ROCK, LORING AIR FORCE BASE, LIMESTONE, MAINE

Science.gov (United States)

This report details a research project on Steam Enhanced Remediation (SER) for the recovery of volatile organic compounds from fractured limestone that was carried out at the Quarry at the former Loring Air Force Base in Limestone, Maine. This project was carried out by USEPA, Ma...

Ecological Study in Two Quarried Limestone Karst Hills in Bogor West Java: Vegetation Structure and Floristic Composition

OpenAIRE

SATYANTI, ANNISA; CANDRA KUSUMA, YAYAN WAHYU

2010-01-01

Many species extinctions have probably gone unnoticed on limestone that was destroyed before they could be sampled. Unless biodiversity surveys are intensified, the true magnitude of extinctions will never be ascertained. The objectives of this study were to determine tree species composition of limestone hills in Nyungcung and Ciampea; to determine quantitatively the dominant and less dominant species and to quantify floristic structure of the two limestone hills. Value of richness (Menhinic...

The Biot coefficient for a low permeability heterogeneous limestone

Science.gov (United States)

Selvadurai, A. P. S.

2018-04-01

This paper presents the experimental and theoretical developments used to estimate the Biot coefficient for the heterogeneous Cobourg Limestone, which is characterized by its very low permeability. The coefficient forms an important component of the Biot poroelastic model that is used to examine coupled hydro-mechanical and thermo-hydro-mechanical processes in the fluid-saturated Cobourg Limestone. The constraints imposed by both the heterogeneous fabric and its extremely low intact permeability [K \\in (10^{-23},10^{-20}) m2 ] require the development of alternative approaches to estimate the Biot coefficient. Large specimen bench-scale triaxial tests (150 mm diameter and 300 mm long) that account for the scale of the heterogeneous fabric are complemented by results for the volume fraction-based mineralogical composition derived from XRD measurements. The compressibility of the solid phase is based on theoretical developments proposed in the mechanics of multi-phasic elastic materials. An appeal to the theory of multi-phasic elastic solids is the only feasible approach for examining the compressibility of the solid phase. The presence of a number of mineral species necessitates the use of the theories of Voigt, Reuss and Hill along with the theories proposed by Hashin and Shtrikman for developing bounds for the compressibility of the multi-phasic geologic material composing the skeletal fabric. The analytical estimates for the Biot coefficient for the Cobourg Limestone are compared with results for similar low permeability rocks reported in the literature.

Submarine terrace limestones from the continental slope off Saurashtra-Bombay: Evidence of Late Quaternary neotectonic activity

Digital Repository Service at National Institute of Oceanography (India)

Rao, V.P.; Veerayya, M.

cements occur as isopachous crusts. Dissolution and clotting of aragonite needles and drusy calcite in the interstices indicate cementation of the limestones at inter-tidal conditions. The age of the limestones is 11,900 years BP. These imply that the 130...

Limestone particle attrition and size distribution in a small circulating fluidized bed

Energy Technology Data Exchange (ETDEWEB)

Zhongxiang Chen; John R. Grace; C. Jim Lim [University of British Columbia, Vancouver, BC (Canada). Department of Chemical and Biological Engineering

2008-06-15

Limestone particle attrition was investigated in a small circulating fluidized bed reactor at temperatures from 25 to 850{sup o}C, 1 atm pressure and superficial gas velocities from 4.8 to 6.2 m/s. The effects of operating time, superficial gas velocity and temperature were studied with fresh limestone. No calcination or sulfation occurred at temperatures {le} 580{sup o}C, whereas calcination and sulfation affected attrition at 850{sup o}C. Increasing the temperature (while maintaining the same superficial gas velocity) reduced attrition if there was negligible calcination. Attrition was high initially, but after about 24 h, the rate of mass change became constant. The ratio of initial mean particle diameter to that at later times increased linearly with time and with (U{sub g} - U{sub mf}){sup 2}, while decreasing exponentially with temperature, with an activation energy for fresh limestone of -4.3 kJ/mol. The attrition followed Rittinger's surface theory. The change of surface area of limestone particles was proportional to the total excess kinetic energy consumed and to the total attrition time, whereas the change of surface area decreased exponentially with increasing temperature. At 850{sup o}C, the attrition rate of calcined lime was highest, whereas the attrition rate was lowest for sulfated particles. When online impact attrition was introduced, the attrition rate was about an order of magnitude higher than without impacts. 25 refs., 14 figs., 4 tabs.

Accurate diffraction data integration by the EVAL15 profile prediction method : Application in chemical and biological crystallography

NARCIS (Netherlands)

Xian, X.

2009-01-01

Accurate integration of reflection intensities plays an essential role in structure determination of the crystallized compound. A new diffraction data integration method, EVAL15, is presented in this thesis. This method uses the principle of general impacts to predict ab inito three-dimensional

Limestone: some observations on luminescence in the region of 360 nm

International Nuclear Information System (INIS)

Galloway, R.B.

2003-01-01

An empirical study of luminescence around 360 nm from limestone is presented. Thermoluminescence glow curves from natural limestone show broad peaks at 440 deg. C, 350 deg. C, 530 deg. C and 286 deg. C in order of decreasing amplitude in contrast to the usual observation, for luminescence around 535 nm, of a sharp peak at 286 deg. C with a broader less intense peak at 350 deg. C. Recuperation occurs around 350 deg. C and 525 deg. C, which has a time dependence consistent with quantum tunnelling. Dependent on the history of heating and light exposure of the sample, sharp peaks at about 325 deg. C and 425 deg. C can be observed. Laboratory irradiated limestone shows a peak at 140 deg. C. The stimulation of luminescence by light of 470 nm with preheating at 145 deg. C for 300 s, shows an increasing signal for successive cycles of measurement associated with the heating, light exposure having little influence. Beta irradiation of a sample, with the same measurement conditions, gives a signal which increases in proportion to radiation dose but which does not survive storage for 17 h. Time resolved luminescence spectra, with no preheating, show a luminescence lifetime between stimulation and emission of less than a few μs for natural limestone, and an exponential increase in signal with increase in temperature (over the rang 20-167 deg. C) during stimulation. A signal proportional to laboratory applied beta dose is measurable at room temperature, with lifetime between stimulation and emission of this signal of 35 μs, but it does not survive heating to 100 deg. C

Combining structural modeling with ensemble machine learning to accurately predict protein fold stability and binding affinity effects upon mutation.

Directory of Open Access Journals (Sweden)

Niklas Berliner

Full Text Available Advances in sequencing have led to a rapid accumulation of mutations, some of which are associated with diseases. However, to draw mechanistic conclusions, a biochemical understanding of these mutations is necessary. For coding mutations, accurate prediction of significant changes in either the stability of proteins or their affinity to their binding partners is required. Traditional methods have used semi-empirical force fields, while newer methods employ machine learning of sequence and structural features. Here, we show how combining both of these approaches leads to a marked boost in accuracy. We introduce ELASPIC, a novel ensemble machine learning approach that is able to predict stability effects upon mutation in both, domain cores and domain-domain interfaces. We combine semi-empirical energy terms, sequence conservation, and a wide variety of molecular details with a Stochastic Gradient Boosting of Decision Trees (SGB-DT algorithm. The accuracy of our predictions surpasses existing methods by a considerable margin, achieving correlation coefficients of 0.77 for stability, and 0.75 for affinity predictions. Notably, we integrated homology modeling to enable proteome-wide prediction and show that accurate prediction on modeled structures is possible. Lastly, ELASPIC showed significant differences between various types of disease-associated mutations, as well as between disease and common neutral mutations. Unlike pure sequence-based prediction methods that try to predict phenotypic effects of mutations, our predictions unravel the molecular details governing the protein instability, and help us better understand the molecular causes of diseases.

Attrition of limestones by impact loading in fluidized beds: The influence of reaction conditions

Energy Technology Data Exchange (ETDEWEB)

Scala, Fabrizio [Istituto di Ricerche sulla Combustione, Consiglio Nazionale delle Ricerche, Napoli (Italy); Salatino, Piero [Istituto di Ricerche sulla Combustione, Consiglio Nazionale delle Ricerche, Napoli (Italy); Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, Napoli (Italy)

2010-09-15

The extent of attrition associated with impact loading was studied for five different limestones pre-processed in fluidized bed under different reaction conditions. The experimental procedure was based on the measurement of the amount and the particle size distribution of the debris generated upon impact of sorbent samples against a target at velocities between 10 and 45 m/s. The effect of calcination, sulfation and calcination/re-carbonation on impact damage was assessed. Fragmentation by impact loading of the limestones was significant and increased with the impact velocity. Lime samples displayed the largest propensity to undergo impact damage, followed by sulfated, re-carbonated and raw limestones. Fragmentation of the sulfated samples followed a pattern typical of the failure of brittle materials. On the other hand, the behaviour of lime samples better conformed to a disintegration failure mode, with extensive generation of very fine fragments. Raw limestone and re-carbonated lime samples followed either of the two patterns depending on the sorbent nature. The extent of particle fragmentation increased after multiple impacts, but the incremental amount of fragments generated upon one impact decreased with the number of successive impacts. (author)

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

Geologic framework and hydrogeologic characteristics of the Glen Rose limestone, Camp Stanley Storage Activity, Bexar County, Texas

Science.gov (United States)

Clark, Allan K.

2004-01-01

The Trinity aquifer is a regional water source in the Hill Country of south-central Texas that supplies water for agriculture, commercial, domestic, and stock purposes. Rocks of the Glen Rose Limestone, which compose the upper zone and upper part of the middle zone of the Trinity aquifer, crop out at the Camp Stanley Storage Activity (CSSA), a U.S. Army weapons and munitions supply, maintenance, and storage facility in northern Bexar County (San Antonio area) (fig. 1). On its northeastern, eastern, and southern boundaries, the CSSA abuts the Camp Bullis Training Site, a U.S. Army field training site for military and Federal government agencies. During 2003, the U.S. Geological Survey (USGS), in cooperation with the U.S. Army, studied the outcropping Glen Rose Limestone at the CSSA and immediately adjacent area (Camp Stanley study area, fig. 1) to identify and map the hydrogeologic subdivisions and faults of the Glen Rose Limestone at the facility. The results of the study are intended to help resource managers improve their understanding of the distribution of porosity and permeability of the outcropping rocks, and thus the conditions for recharge and the potential for contaminants to enter the Glen Rose Limestone. This study followed a similar study done by the USGS at Camp Bullis (Clark, 2003). The purpose of this report is to present the geologic framework and hydrogeologic characteristics of the Glen Rose Limestone in the study area. The hydrogeologic nomenclature follows that introduced by Clark (2003) for the outcropping Glen Rose Limestone at Camp Bullis in which the upper member of the Glen Rose Limestone (hereinafter, upper Glen Rose Limestone), which is coincident with the upper zone of the Trinity aquifer, is divided into five intervals on the basis of observed lithologic and hydrogeologic properties. An outcrop map, two generalized sections, related illustrations, and a table summarize the description of the framework and distribution of characteristics.

Dynamic failure of dry and fully saturated limestone samples based on incubation time concept

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Yuri V. Petrov

2017-02-01

Full Text Available This paper outlines the results of experimental study of the dynamic rock failure based on the comparison of dry and saturated limestone samples obtained during the dynamic compression and split tests. The tests were performed using the Kolsky method and its modifications for dynamic splitting. The mechanical data (e.g. strength, time and energy characteristics of this material at high strain rates are obtained. It is shown that these characteristics are sensitive to the strain rate. A unified interpretation of these rate effects, based on the structural–temporal approach, is hereby presented. It is demonstrated that the temporal dependence of the dynamic compressive and split tensile strengths of dry and saturated limestone samples can be predicted by the incubation time criterion. Previously discovered possibilities to optimize (minimize the energy input for the failure process is discussed in connection with industrial rock failure processes. It is shown that the optimal energy input value associated with critical load, which is required to initialize failure in the rock media, strongly depends on the incubation time and the impact duration. The optimal load shapes, which minimize the momentum for a single failure impact, are demonstrated. Through this investigation, a possible approach to reduce the specific energy required for rock cutting by means of high-frequency vibrations is also discussed.

Diagenetic evolution and stable isotopes of Lower Permian platform marginal carbonates (Trogkofel Limestone, Carnic Alps, Austria)

Science.gov (United States)

Schaffhauser, Maria; Krainer, Karl; Sanders, Diethard Gerald; Spötl, Christoph

2010-05-01

The Trogkofel massif in the Carnic Alps, Austria/Italy, consists of a succession up to 400 m thick of limestones deposited along a platform margin (Trogkofel Limestone; Artinskian). The top of the Trogkofel Limestone is erosively overlain by the Tarvis Breccia. Up-section, the Trogkofel Limestone consists of well-bedded shallow-water bioclastic limestones with intercalated mud mounds, overlain by thick-bedded to unbedded limestones (bioclastic grainstones, packstones, rudstones) and cementstone mounds rich in phylloid algae, Tubiphytes, bryozoans and Archaeolithoporella. In the cementstone mounds, bioclasts are coated by thick fringes and botryoids of fibrous calcite, and of calcite spar that probably represents calcitized aragonite. Primary and intrinsic pores are filled by microbialite, and/or by mudstone to bioclastic wackestone. Shallow-water bioclastic grainstones are cemented by isopachous fringes of fibrous calcite, or by sparry calcite. Throughout the succession, evidence for meteoric-vadose dissolution is present. The Trogkofel Limestone is riddled by palaeokarstic dykes and caverns filled by (a) isopachous cement fringes up to a few decimetres thick, and/or (b) by red, geopetally-laminated lime mudstone to bio-lithoclastic wackestone; geopetal laminasets locally display convolute bedding. Small dissolution cavities are filled by grey internal sediment, or by crystal silt. Brecciated internal sediments overlain by unbrecciated, geopetally-laminated infillings record deformation during or after deposition of the Trogkofel Limestone. Polyphase fractures cemented by calcite may cross-cut both internal sediments and host rock. In the Trogkofel Limestone, local dolomitization is common. Replacement dolomites show a wide range of shapes and fabrics, including: (a) fine-crystalline anhedral xenotopic fabric, (b) coarse-crystalline subhedral to euhedral, hypidiotopic to idiotopic fabric of turbid or optically zoned crystals, and (c) saddle dolomite as replacement

Innovative Field Investigations in Limestone using a FACT-FLUTe

DEFF Research Database (Denmark)

Mosthaf, Klaus; Barrett Sørensen, Mie; Broholm, Mette Martina

2015-01-01

and the prevailing aqueous pore water concentrations for a range of hydraulic parameters and conditions typical for limestone aquifers. Results and outlook The sorption experiments showed very strong sorption with reasonably linear sorption isotherms over a very large concentration range for individual chlorinated...

Colmenar limestone as a resource for built heritage

Science.gov (United States)

Fort, Rafael; Álvarez de Buergo, Mónica; Varas-Muriel, MªJosé; Mercedes Pérez-Monserrat, Elena

2013-04-01

The Colmenar stone (or Colmenar limestone) has been used in the construction of significant builidings of the Central area of Spain, such as the Royal Palace of Aranjuez (16th -18th centuries) or the Royal Palace of Madrid (18th century). Nowadays this building stone is still widely used, both for new construction and restoration works, as well as for the indoor ornamentation of emblematic buildings such as the Royal Theater of Madrid (20th century). There are many quarries from where this stone was exploited, being the most prestigious ones those located in Colmenar de Oreja, at 50 km Southeast the city of Madrid. The high quality of the stone in these quarries, its whiteness and pureness, made this locality the most relevant in these stonés extractive activities, concentrating the most relevant exploitations and providing the stone the denomination of the municipality (Colmenar). It was an underground mining extraction until the 20th century in order to reach the highest quality level of the mine, the so called "Banco Gordo" (Thick Bank). Generically known as moorland limestone, this rock belongs to the fluvial-lacustrine carbonates of the Upper Miocene Unit of the Tertiary Madrid's Basin. Its tonality mainly ranges from white to cream and even light grey. Under a petrographic point of view, this limestone is constituted by 40% of bioclasts (characea, ostracods and gasteropods), 20-30% of micritic matrix and 30-40% of sparitic cement. Therefore, it can be classified as a biomicrite/biosparite limestone or as a bioclastic packstone. Some particularities of these limestones regarding their appearance are related to some karstic processes they underwent linked to some dissolution phenomena during the Pliocene. All of this resulted on an abundance of cavities with terra rossa fillings, a non-soluble clayey residue, iron enriched, which is the responsible for the reddish and pinkish color that the Colmenar stone sometimes shows. These petrographic characteristics

Adsorption of anionic surfactants in limestone medium during oil recovery

Energy Technology Data Exchange (ETDEWEB)

Canbolat, Serhat; Bagci, Suat [Middle East Technical Univ., Dept. of Petroleum and Natural Gas Engineering, Ankara (Turkey)

2004-07-15

Foam-forming surfactant performance was evaluated by several experimental methods (interfacial tension, foam stability, corefloods) using commercial surfactants. There is considerable interest in the use of foam-forming surfactants for mobility control in water flood. To provide effective mobility control, the injected surfactant must propagate from the injection well toward the production well. One of the important parameters affecting propagation of foam-forming surfactant through the reservoir is the retention of surfactant due to its adsorption on reservoir rock. The determination of the adsorption of foam-forming surfactants in limestone reservoirs is important for the residual oil recovery efficiency. Adsorption measurements, recovery efficiencies, and surfactant and alkaline flooding experiments carried out with the representative of the selected surfactants alkaline solutions, linear alkyl benzene sulphonic acid (LABSA), sodium lauryl ether sulfate (SLES), and NaOH in a limestone medium. These surfactants were selected with respect to their foaming ability. Calibration curves formed by pH measurements were used to determine the correct adsorption amount of the used surfactants and recovery efficiency of these surfactants compared with base waterflooding. The results showed that LABSA adsorbed more than SLES in limestone reservoirs. The recovery efficiency of SLES was higher than the recovery efficiency of LABSA, and they decreased the recovery efficiency with respect to only the water injection case. (Author)

Decomposition and reduction of N2O over Limestone under FBC Conditions

DEFF Research Database (Denmark)

Johnsson, Jan Erik; Jensen, Anker; Vaaben, Rikke

1997-01-01

The addition of limestone for sulfur retention in FBC has in many cases been observed to influence the emission of N2O. The catalytic activity of N2O over calcined Stevns Chalk for decomposition of N2O in a laboratory fixed bed quartz reactor was measured. It was found that calcined Stevns Chalk...... is a very active catalyst for N2O decomposition in an inert atmosphere, and the presence of 3 vol% CO increased the rate of N2O destruction by a factor of 5 due to the catalytic reduction of N2O by CO. The activity decreased with increasing CO2 concentration, and uncalcined or recarbonated limestone had...... negligible activity. Sulfation of the calcined limestone under oxidizing conditions lowered the activity, however sulfidation under reducing conditions showed that CaS is an active catalyst for the reduction of N2O by CO. Without CO present a gas solid reaction between N2O and CaS takes place and SO2...

Laser removal of water repellent treatments on limestone

Energy Technology Data Exchange (ETDEWEB)

Gomez-Heras, Miguel; Alvarez de Buergo, Monica; Rebollar, Esther; Oujja, Mohamed; Castillejo, Marta; Fort, Rafael

2003-12-15

Protective and water repellent treatments are applied on stone materials used on buildings or sculptures of artistic value to reduce water intrusion without limiting the natural permeability to water vapour of the material. The effect of the wavelength associated with the laser removal of two water repellent treatments applied on limestone, Paraloid B-72, a copolymer of methyl acrylate and ethyl methacrylate, and Tegosivin HL-100, a modified polysiloxane resin, was investigated by using the four harmonics of a Q-switched Nd:YAG laser (1064, 532, 355 and 266 nm). The modifications induced on the surface of limestone samples by laser irradiation were studied using colorimetry, roughness measurements and scanning electron microscopy (SEM). The removal of the treatments was found to be dependent on the laser irradiation conditions and on the characteristics of the coatings. The fundamental laser radiation was effective in removing both treatments, but thermal alteration processes were induced on the constituent calcite crystals. The best results were obtained by irradiation in the near UV at 355 nm.

Lithofacies palaeogeography and biostratigraphy of the lowermost horizons of the Middle Triassic Hallstatt Limestones (Argolis Peninsula, Greece

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Fotini A. Pomoni

2013-07-01

Taking into consideration the present location of the Hallstatt Formation, in the context of the Hellenides, an area suitable for the deposition of the Hallstatt Limestones, should be located between the sub-Pelagonian (western part of the Pelagonian zone and Pindos geotectonic zones, which during the Triassic corresponded to a platform slope and a deep ocean, respectively. The widespread Middle Triassic Han Bulog Limestones (ammonoid-bearing pelagic limestones from Triassic successions of the Eastern Alps (Dinarides, Hellenides may have formed partly in similar slope environments.

Investigation of oil production conditions and production operation by solution gas drive in low permeable heterogeneous limestones

Energy Technology Data Exchange (ETDEWEB)

Lillie, W

1966-04-01

It was the purpose of this study to investigate the production of oil and gas from a low permeable heterogeneous limestone-reservoir by solution gas drive. The rock-samples were subjected to extensive petrolphysical analyses in order to characterize the pore structure of of the limestone material. Laboratory model flow tests were undertaken to outline in detail the production history during the pressure depletion process under reservoir conditions and by using original reservoir fluids. The experiments were carried out at different rates of pressure decline. It can be stated that the rate of pressure decline is the most important factor affecting the oil recovery and the development of the gas-oil-ratio in a model flow test. The present investigation leads to the following conclusion: It is posible to get reliable results which could be the base for a reservoir performance prediction only when the gas and oil phase are maintained at equilibrium conditions within the rock sample during the pressure decline. An additional calculation of the solution gas drive reservoir production history by the Tarner method shows a good agreement of the experimental and the calculated data. (40 refs.)

Use of limestone obtained from waste of the mussel cannery industry for the production of mortars

International Nuclear Information System (INIS)

Ballester, Paloma; Marmol, Isabel; Morales, Julian; Sanchez, Luis

2007-01-01

Various types of cement-SiO 2 -CaCO 3 mortar were prepared by replacing quarry limestone aggregate with limestone obtained as a by-product from waste of the mussel cannery industry. The CaCO 3 aggregate consists mainly of elongated prismatic particles less than 4 μm long rather than of the rounded particles of smaller size (2-6 μm) obtained with quarry limestone. The mechanical and structural properties of the mortars were found to be influenced by aggregate morphology. Setting of the different types of mortar after variable curing times was evaluated by scanning electron microscopy (SEM), thermogravimetric analysis (TG) and mercury intrusion porosimetry (MIP) techniques. Mortars with a high content in mussel shell limestone exhibited a more packed microstructure, which facilitates setting of cement and results in improved mortar strength. The enhanced mechanical properties of the new mortars allow the cement content in the final mortar composition to be decreased and production costs to be reduced as a result

Quasi-closed phase forward-backward linear prediction analysis of speech for accurate formant detection and estimation.

Science.gov (United States)

Gowda, Dhananjaya; Airaksinen, Manu; Alku, Paavo

2017-09-01

Recently, a quasi-closed phase (QCP) analysis of speech signals for accurate glottal inverse filtering was proposed. However, the QCP analysis which belongs to the family of temporally weighted linear prediction (WLP) methods uses the conventional forward type of sample prediction. This may not be the best choice especially in computing WLP models with a hard-limiting weighting function. A sample selective minimization of the prediction error in WLP reduces the effective number of samples available within a given window frame. To counter this problem, a modified quasi-closed phase forward-backward (QCP-FB) analysis is proposed, wherein each sample is predicted based on its past as well as future samples thereby utilizing the available number of samples more effectively. Formant detection and estimation experiments on synthetic vowels generated using a physical modeling approach as well as natural speech utterances show that the proposed QCP-FB method yields statistically significant improvements over the conventional linear prediction and QCP methods.

The Diversity and Productivity of Indigenous Forage in Former Limestone Mining Quarry in Karst Mountain of Southern Gombong, Central Java Indonesia

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Doso Sarwanto

2015-05-01

Full Text Available Indonesia is a country that has a lot of limestone mountains, covering 15.4 million hectares. Limestone mountains have strategic functions as limestone is used as building materials and as raw material in cement industry. Therefore, limestone mining quarry in various areas of limestone mountains in Indonesia is increasingly widespread. The biggest negative impact of limestone mining is the formed open land which is abandoned and unutilized. Changes in the ecosystem will lead to the reduced levels of diversity and productivity of indigenous forage which will ultimately reduce the performance and development of ruminants livestock kept by farmers in the mountainous region of limestone. This study aims to determine the diversity and productivity of indigenous forage on former limestone mining quarry in limestone mountains of southern Gombong. The research was conducted through survey by identifying and measuring the forage production of sample plots assigned purposively. Location of the study was divided into three categories, mild, moderate and heavy mining. Results showed that soil fertility levels in open fields of former limestone mining in southern Gombong mountains are low with total N content of 0.049 - 0.141%, total P2O5 of 0.067 - 0.133% and total K2O of 0.086 - 0.100%. The diversity of indigenous forage on mild mining was more diverse than that of moderate and heavy mining, i.e. 13 species comprising 7 grass species, 2 legumes species, and 4 species of shrubs. The most dominant species in all mining categories are Cynodon dactylon, Imperata cylindrica, Ageratum conyzoides and Mikania micrantha. The results also showed that in the open land of mild mining had the highest production of fresh and dry matter compared to that of moderate and severe mining

An accurate model for numerical prediction of piezoelectric energy harvesting from fluid structure interaction problems

International Nuclear Information System (INIS)

Amini, Y; Emdad, H; Farid, M

2014-01-01

Piezoelectric energy harvesting (PEH) from ambient energy sources, particularly vibrations, has attracted considerable interest throughout the last decade. Since fluid flow has a high energy density, it is one of the best candidates for PEH. Indeed, a piezoelectric energy harvesting process from the fluid flow takes the form of natural three-way coupling of the turbulent fluid flow, the electromechanical effect of the piezoelectric material and the electrical circuit. There are some experimental and numerical studies about piezoelectric energy harvesting from fluid flow in literatures. Nevertheless, accurate modeling for predicting characteristics of this three-way coupling has not yet been developed. In the present study, accurate modeling for this triple coupling is developed and validated by experimental results. A new code based on this modeling in an openFOAM platform is developed. (paper)

Downflow limestone beds for treatment of net-acidic, oxic, iron-laden drainage from a flooded anthracite mine, Pennsylvania, USA: 2. Laboratory evaluation

Science.gov (United States)

Cravotta, C.A.; Ward, S.J.; Hammarstrom, J.M.

2008-01-01

Acidic mine drainage (AMD) containing elevated concentrations of dissolved iron and other metals can be neutralized to varying degrees by reactions with limestone in passive treatment systems. We evaluated the chemical and mineralogical characteristics and the effectiveness of calcitic and dolomitic limestone for the neutralization of net-acidic, oxic, iron-laden AMD from a flooded anthracite mine. The calcitic limestone, with CaCO3 and MgCO3 contents of 99.8 and treatment system in 2003 at the Bell Mine, a large source of AMD and baseflow to the Schuylkill River in the Southern Anthracite Coalfield, in east-central Pennsylvania. In the winter of 2002-2003, laboratory neutralization-rate experiments evaluated the evolution of effluent quality during 2 weeks of continuous contact between AMD from the Bell Mine and the crushed calcitic or dolomitic limestone in closed, collapsible containers (cubitainers). The cubitainer tests showed that: (1) net-alkaline effluent could be achieved with detention times greater than 3 h, (2) effluent alkalinities and associated dissolution rates were equivalent for uncoated and Fe(OH)3-coated calcitic limestone, and (3) effluent alkalinities and associated dissolution rates for dolomitic limestone were about half those for calcitic limestone. The dissolution rate data for the cubitainer tests were used with data on the volume of effuent and surface area of limestone in the treatment system at the Bell Mine to evaluate the water-quality data for the first 1.5 years of operation of the treatment system. These rate models supported the interpretation of field results and indicated that treatment benefits were derived mainly from the dissolution of calcitic limestone, despite a greater quantity of dolomitic limestone within the treatment system. The dissolution-rate models were extrapolated on a decadal scale to indicate the expected decreases in the mass of limestone and associated alkalinities resulting from the long-term reaction of

Improving DMS 9210 requirements for limestone rock asphalt - final report.

Science.gov (United States)

2015-03-01

Limestone Rock Asphalt (LRA) mixtures have been produced and placed for several decades using : specification requirements currently listed under DMS 9210. Several districts have had placement issues : and premature failures at the beginning of 2010....

Lightweight concrete with Algerian limestone dust. Part II: study on 50% and 100% replacement to normal aggregate at timely age

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S. Kitouni

2015-12-01

Full Text Available Abstract A control lightweight concrete (LWC mixture made with 50% and 100% of limestone as a replacement of coarse aggregates in weight was prepared. Limestone is used for economical and environmental concern. The concrete samples were cured at 65% relative humidity at 20 ºC. The compressive and flexural tensile strengths, elastic modulus and Poisson's ratio of hardened concrete were measured. Laboratory compressive and tensile strength tests results showed that LWC can be produced by the use of limestone. The aim of this study is twofold: one is to design a lightweight concrete with the use of limestone that will provide an advantage of reduction in dead weight of a structure; and second is to obtain a more economical LWC mixture with the use of limestone.

Hydrate Phase Assemblages in Calcium Sulfoaluminate - Metakaolin - Limestone Blends

DEFF Research Database (Denmark)

Pedersen, Malene Thostrup; Lothenbach, Barbara; Winnefeld, Frank

2017-01-01

The combination of a commercial calcium sulfoaluminate (CSA) cement with metakaolin (MK) and limestone (LS) as supplementary cementitious materials (SCMs) is investigated for a CSA replacement level of 20 wt%. In addition to a pure CSA cement, paste samples have been prepared for three blends wit...

Performance of japanese quails fed feeds containing different corn and limestone particle sizes

OpenAIRE

Berto,DA; Garcia,EA; Móri,C; Faitarone,ABG; Pelícia,K; Molino,AB

2007-01-01

This study aimed at evaluating performance and egg quality of Japanese quails fed feeds containing different corn and limestone particle sizes. A total number of 648 birds in the peak of production was distributed in a random complete block experimental design, using a 2x3 factorial arrangement (2 corn particle sizes and 3 limestone particle sizes). Birds were designated to one of two blocks, with six replicates of 18 birds each. Mean geometric diameter (MGD) values used were 0.617mm and 0.72...

The influence of combustion derived pollutants on limestone deterioration

DEFF Research Database (Denmark)

Johnson, JB; Montgomery, Melanie; Thompson, GE

1996-01-01

This study concerns quantification of the relative chemical degradation effects of dry deposition of combustion-derived atmospheric pollutants, HCl, SO2 and NO2, on Portland and Monks Park limestones, employing laboratory exposure chambers for periods of 30 days. Using presentation rates up to 40 x...... 10(-4) mu g cm(-2) s(-1), the pollutants were assessed individually and in various combinations, along with ozone as oxidant, at 84% RH with dry or water-wetted surfaces. The degradation was followed by analysis of exposed stone, for Cl-, SO42- and NO3-, and of run-off solution for Ca2+, in addition...... to the anions. From these data, the total calcium released from limestone to reaction ions and products and the percentages of each pollutant reacted (and so the deposition velocity (V-D)) in each exposure regime were calculated. HCl acted independently of the presence of other pollutants, showed 40 and 100...

Rheology, strain localization and stress history in the limestones of Bure (Meuse, France)

International Nuclear Information System (INIS)

Rolland, A.

2013-01-01

In order to demonstrate the feasibility of a radioactive waste repository (HLW) in clay-stone formation, the french national radioactive waste management agency (Andra) started in 2000 to build an underground research laboratory (URL) at Bure in the south of the Meuse district. The target horizon for the laboratory is a 135 m thick layer of argillaceous rock (Callovo-Oxfordian clay-stone) that lies between about 420 and 555 meters below the surface at the URL site. The argillite layer (COX) is surrounded by limestones from the Dogger and the Oxfordian ages (respectively 164,7 to 175,6 Ma and 161,2 to 164,7 Ma). Numerous stylolites were found in these limestones. The aim of this work is to study the rheology of these stylolites-rich horizons and the stylolites as stress gauges in the Dogger and Oxfordian formations. In this work, a wide range of samples with and without stylolites were sampled in the Dogger and Oxfordian formations. Petrophysical measurements and microstructural studies showed that all these limestones have a microporous structure. We showed that the stylolites induced significant variations in some physical properties and in the rock strength. Based on an analytical model, presented here in details, linking a characteristic length associated to the stylolites morphology and the stress associated to the development of that stylolites, a method for the morphology analysis of stylolites is developed, using a Fourier power spectrum technique, by taking into account all the difficulties linked to the use of cores from deep boreholes. We apply this method on stylolites at various depths, starting from the Oxfordian formation at a depth of 158 meters to the Dogger formation at a depth of 800 meters. No stylolites are found in the intermediate Callovo-Oxfordian clay-stone formation. We analyze 1D profiles taken on the outer part of the cores. In agreement with theoretical predictions, we always observe two regimes for small and large scales separated by a

Thermal effects induced by laser ablation in non-homogeneous limestone covered by an impurity layer

Science.gov (United States)

Cocean, Alexandru; Pelin, Vasile; Cazacu, Marius Mihai; Cocean, Iuliana; Sandu, Ion; Gurlui, Silviu; Iacomi, Felicia

2017-12-01

This paper reports preliminary results concerning thermal effects induced by urban/industrial air pollutants deposited on a limestone rock when heated by pulsed laser in the cleaning process. The process of laser cleaning treatment of the crust is simulated using COMSOL Multiphysics 4.4, finite element analysis software. Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy and Laser Induced Breakdown Spectroscopy techniques have been used to analyze the chemical composition of the samples. Two elements found as being present into the dust and in the crust, such as iron and magnesium particles are used for simulation in COMSOL. Therefore, the profiles heat evolutions on the crust surface and inside limestone are obtained as thermal interactions between the three components (iron, magnesium and limestone), simulating the non-homogeneous materials. It has been observed that iron impurities caused by the dust deposition may damage the limestone through a process of overheating, as a consequence of a high thermal conduction phenomenon, recorded for the region with iron impurities and sizes of micrometric order are localized. The thermal contact between the three components results in plots that reflect their thermal interactions.

An experimental study on the primary fragmentation and attrition of limestones in a fluidized bed

International Nuclear Information System (INIS)

Yao, Xuan; Zhang, Hai; Yang, Hairui; Liu, Qing; Wang, Jinwei; Yue, Guangxi

2010-01-01

In this paper, an experimental study on the primary fragmentation and attrition of 5 limestones in a fluidized bed was conducted. The intensity of fragmentation and attrition were measured in the same apparatus but at different fluidizing velocities. It was found that the averaged size of the particles decreased by about 10-20% during the fragmentation process. The important factors for particle comminution include limestone types, heating rate, calcination condition and ambient CO 2 concentration. Fragmentation mainly occurred in the first a few minutes in the fluidized bed and it was more intense than that in the muffle furnace at the same temperature. The original size effect was ambiguous, depending on the limestone type. The comminution caused by attrition mainly occurred during calcination process rather than sulphation process. The sulphation process was fragmentation and attrition resisted. The attrition rate of sulphate was similar to that of lime in trend, decaying exponentially with time, but was one-magnitude-order smaller than that of lime. Present experimental results indicate that fragmentation mechanism of the limestone is dominated by CO 2 release instead of thermal stress. (author)

Biogenic magnetite as a primary remanence carrier in limestone deposits

Science.gov (United States)

Chang, Shih-Bin R.; Kirschvink, Joseph L.; Stolz, John F.

1987-06-01

Studies on the microbial communities and magnetic phases of samples collected from carbonate oozes at Sugarloaf Key, FL, U.S.A. and calcareous laminated sediments from Laguna Figueroa, Baja California, Mexico have revealed the existence of magnetotactic bacteria and ultrafine-grained single domain magnetite in both environments. Magnetotactic bacteria were identified by light and electron microscopy. The single domain magnetite was detected by coercivity spectra analysis with a SQUID magnetometer and examined under the transmission electron microscope. The similarity, in terms of size and shape, between the single domain magnetite found in these sediments and the magnetite observed in the bacterial magnetosome from enriched cultures indicates the ultrafine-grained magnetite in these two marine environments was biologically formed. These results, combined with the common occurrences of ultrafine-grained magnetite in limestone deposits detected rock magnetically, suggest biogenic magnetite may be present and contribute to the magnetic remanence in these rocks. Several Cambrian limestone samples, separately collected from Siberia, China, and Kazakhstan, were examined for the presence of bacterial magnetite. Samples from the Lower Cambrian Sinskian Formation at Siberia Platform were found to contain both a large amount of apparently bacterial magnetite particles and a very stable primary magnetic component. Post-Cambrian diagenesis does not seem to affect the microgranulometry of these apparently bacterial magnetite crystals or the magnetic remanence carried by them. Assessing the potential role of biogenic magnetite as a primary remanence carrier in other Phanerozoic limestone deposits ought to be further pursued.

Mechanical and chemical compaction in fine-grained shallow-water limestones.

Science.gov (United States)

Shinn, E.A.; Robbin, D.M.

1983-01-01

Significant mechanical compaction resulted from pressures simulating less than 305 m of burial. Increasing loads to an equivalent of more than 3400 m did not significantly increase compaction or reduce sediment core length. Chemical compaction (pressure dissolution) was detected only in sediment cores compacted to pressures greater than 3400 m of burial. These short-term experiments suggest that chemical compaction would begin at much shallower depths given geologic time. Compaction experiments that caused chemical compaction lend support to the well-established hypothesis; that cement required to produce a low-porosity/low-permeability fine-grained limestone is derived internally. Dissolution, ion diffusion, and reprecipitation are considered the most likely processes for creating significant thicknesses of dense limestone in the geologic record. Continuation of chemical compaction after significant porosity reduction necessitates expulsion of connate fluids, possibly including hydrocarbons. -from Authors

Microfacies and Diagenetic Fabric of the Lockhart Limestone, Kotal Pass Section, Northeast of Kohat, Pakistan

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Muhammad Waseem Khan

2016-06-01

Full Text Available The present study is intended to describe the carbonate microfacies of the Paleocene Lockhart Limestone in area northeast of the Kohat City. The analyzed limestone in the area is 65m thick and predominantly medium to thick bedded, nodular to brecciated and richly fossiliferous. Thin interbeds of marl are observed in the main lithological unit. The lower contact of the Lockhart Limestone is faulted with the Samana Suk Formation of the Jurassic age while conformably overlain by the Patala Formation of Paleocene to Eocene age. The major lithological unit is comprised of predominant assemblage of larger benthic and smaller planktonic foraminifers with accretion of ostracods, dasycladacean algae, echinoderms, gastropods and corals. On the basis of field and laboratory observations, two distinct types of microfacies have been identified as i Dasyclad-Miliolid Foram Wacke-Packstone microfacies of the inner shelf, sub tidal lagoon, ii Larger Foram Packstone microfacies of the middle shelf. The Limestone represents a carbonate cyclic sequence marked by three, transgressive, deepening up cycles representing a gradual sea level rise compensated by vertical accumulation of microfacies. The commencement of each cycle is clearly marked by the input of land-derived siliciclastic sediments and near shore restricted marine faunal/floral assemblage in the inner shelf microfacies gradually thinning up section where the microfacies become deeper offshore. The diagenetic modifications are observed in the shape of compactional framework, dolomitization, aragonite to calcite alteration and spar filled fractures in the main lithological unit of the Lockhart Limestone.

Lithofacies and petrophysical properties of Portland Base Bed and Portland Whit Bed limestone as related to durability

NARCIS (Netherlands)

Dubelaar, C.W.; Engering, S.; Hees, R.P.J. van; Koch, R.; Lorenz, H.G.

2003-01-01

This study focuses on the differences in lithofacies and petrophysical properties of Base Bed and Whit Bed Portland limestone and the presumed relationships between these characteristics and the durability of this building stone. As Portland limestone probably will be used as a stone for several

Lithofacies and Petrophysical Properties of Portland Base Bed and Portland Whit Bed Limestone as Related to Durability

NARCIS (Netherlands)

Dubelaar, C.W.; Engering, S.; Van Hees, R.P.J.; Koch, R.; Lorenz, H.G.

2003-01-01

This study focuses on the differences in lithofacies and petrophysical properties of Base Bed and Whit Bed Portland limestone and the presumed relationships between these characteristics and the durability of this building stone. As Portland limestone probably will be used as a stone for several

Holothurian sclerites and conodonts in the Upper Carnian (Tuvalian and Norian Limestones in the Central Kanmik Alps

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Anton Ramovš

1992-12-01

Full Text Available Near Bivouac under the Skuta Mountain (locality 1 in the central Kamnik Alps Upper Carnian Limestones were determined with conodont Epigondolella nodosa Hayashi, holothurian sclerites Calclamnella consona Mostler and C. regularis Stefanov, ammonites and other fossils similar to deeper marine Hallstatt facies of Northern Limestone Alps.Conodonts Epigondolella abneptis (Huckriede and very rich holothurian fauna proved the Norian age for bedded limestones with very frequent large chert nodules on the south slope of the Skuta and on Sleme (loc. 2 and 3. They representdeeper marine facies and a distinct development of the Lower Norian

Limestone and Zeolite as Alternative Media in Horizontal Subsurface Flow Constructed Wetlands: Laboratory-Scale Studies

Science.gov (United States)

Lizama, K.; Jaque, I.; Ayala, J.

2016-12-01

Arsenic is well known for its chronic toxicity. Millions of people around the world are currently at risk, drinking water with As concentrations above 10 ppb, the WHO drinking water guideline. Although different treatment options exist, they are often limited by elevated costs and maintenance requirements. Constructed wetlands are a natural water treatment system, capable to remove metals and metalloids -including As- via different physical, chemical and biological processes. The use of alternative supporting media to enhance As removal in subsurface flow wetlands has been recommended, but not sufficiently studied. Limestone and zeolite have been identified as effective supporting media in subsurface flow wetlands aiming As removal. However, there are still key aspects to be addressed, such as the implications of using these media, the speciation in the solid phase, the role of vegetation, etc. This study investigated the performance of limestone and zeolite in three types of experiments: batch, column and as main supporting media in a bench scale horizontal subsurface flow wetland system. Synthetic water resembling a contaminated river in Chile (As concentration=3 mg/L, Fe concentration= 100 mg/L, pH=2) was used in all experiments. In the batch experiments, the As concentration, the mass of media and the contact time were varied. The column system consisted of three limestone columns and three zeolite columns, operated under a hydraulic loading of 20 mm/d. The wetland system consisted of twelve PVC cells: six filled with zeolite and six with limestone. Phragmites australis were planted in three cells of each media type, as control cells. From the batch experiments, maximum As sorption capacities as indicated by Langmuir model were 1.3 mg/g for limestone and 0.17 mg/g for zeolite, at 18 h contact time and 6.3 g/L medium concentration. EDS and XPS analyses revealed that As and Fe were retained in zeolite at the end of the batch experiments. Zeolite and limestone

Highly accurate prediction of food challenge outcome using routinely available clinical data.

Science.gov (United States)

DunnGalvin, Audrey; Daly, Deirdre; Cullinane, Claire; Stenke, Emily; Keeton, Diane; Erlewyn-Lajeunesse, Mich; Roberts, Graham C; Lucas, Jane; Hourihane, Jonathan O'B

2011-03-01

Serum specific IgE or skin prick tests are less useful at levels below accepted decision points. We sought to develop and validate a model to predict food challenge outcome by using routinely collected data in a diverse sample of children considered suitable for food challenge. The proto-algorithm was generated by using a limited data set from 1 service (phase 1). We retrospectively applied, evaluated, and modified the initial model by using an extended data set in another center (phase 2). Finally, we prospectively validated the model in a blind study in a further group of children undergoing food challenge for peanut, milk, or egg in the second center (phase 3). Allergen-specific models were developed for peanut, egg, and milk. Phase 1 (N = 429) identified 5 clinical factors associated with diagnosis of food allergy by food challenge. In phase 2 (N = 289), we examined the predictive ability of 6 clinical factors: skin prick test, serum specific IgE, total IgE minus serum specific IgE, symptoms, sex, and age. In phase 3 (N = 70), 97% of cases were accurately predicted as positive and 94% as negative. Our model showed an advantage in clinical prediction compared with serum specific IgE only, skin prick test only, and serum specific IgE and skin prick test (92% accuracy vs 57%, and 81%, respectively). Our findings have implications for the improved delivery of food allergy-related health care, enhanced food allergy-related quality of life, and economized use of health service resources by decreasing the number of food challenges performed. Copyright © 2011 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Replacement of Eocene white sandy limestone in historical buildings : over 100 years of practice in the Netherlands

NARCIS (Netherlands)

Quist, W.J.; Nijland, T.G.; Hees, R.P.J. van

2013-01-01

This paper discusses the replacement of white sandy limestone (Gobertange and Lede or Balegem) in the Netherlands in (successive) restorations from the mid-19th century onwards. White sandy limestone, transported from the southern part of the Low Countries (now Belgium), was extensively used in the

The Suitability of Limestone from Pilaspi Formation (Middle-Late Eocene for Building Stone in Koya Area, NE Iraq

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Hemn M. Omar

2015-09-01

Full Text Available Suitability of limestone rocks has a crucial importance when stones are used for constructing modern structure. The purpose of this study is to clarify the links between physical, mechanical properties of limestone rocks, also their quality to use as building materials. A total of six limestone rock samples were collected from three different outcrops locations within Pilaspi Formation in Koya area. Engineering geological and geotechnical properties of the limestone rocks in the study area were determined based on the field studies and laboratory tests. The field studies included observations/ measurements of rock mass characteristics such as color, grain size, orientation, bedding thickness and weathering state of the rock materials also spacing, persistence, roughness and infilling material of the discontinuities. Laboratory tests were carried out for determining water content, water absorption, density, uniaxial compressive strength, slake durability and porosity of the rock materials. The study results go well with the national and international standards (Iraqi Standards, 1989; American Society for Testing and Materials, 2004; International Society for Rock Mechanics, 1981 and have shown that the limestone rocks are acceptable for building stone.

Experimental design for assessment of electrokinetically enhanced delivery of lactate and bacteria in 1,2-cis-dichloroethylene contaminated limestone

DEFF Research Database (Denmark)

Hyldegaard, Bente Højlund; Nedergaard, L. W.; Ottosen, Lisbeth

2015-01-01

Bacterial dechlorination of chlorinated solvents often causes accumulation of the intermediate cis-DCE. Back diffusion of e.g. cis-DCE, due to the dual porosity of limestone, often limits the remediation efficiency. A remediation scheme capable of establishing contact between contaminant, degrading...... bacteria and electron donor within the low permeable limestone matrix is required. The technology EK-BIO, which combines enhanced reductive dechlorination and electrokinetics (EK), was assessed. This novel technology has not previously been tested in limestone. An experimental set-up was designed to meet...... that fermentative bacteria were distributed by electrophoresis. This study suggests that EK application can establish the essential contact and overcome back diffusion. Thereby, EK-BIO may be superior to advection-based technologies for bioremediation of chlorinated solvent contaminated limestone matrices....

Effects of Water and Low-Medium Temperature on Limestone from Mt Etna basement

Science.gov (United States)

Castagna, Angela; Ougier-Simonin, Audrey; Benson, Philip; Browning, John; Fazio, Marco; Walker, Richard; Vinciguerra, Sergio

2017-04-01

Mount Etna volcano, Sicily, sits atop a structurally complex sedimentary basement continuously subjected to tectonic deformation. The flyschoid formations belonging to the Appenninic-Maghrebian Chain (AMC) and making up the accretionary wedge of a regional fold-and-thrust belt lie above carbonate Hyblean Plateau (HP) sequences, belonging to the African plate. Carbonate rocks represent a major component of the sedimentary basement: they are spread throughout the AMC as continuous strata and discontinuous lenses, and are the main constituent (e.g., Comiso Limestone) of the HP foreland. Etna is an active volcanic environment, characterized by complex stress field distributions, magmatic and non-magmatic fluid circulation, and elevated temperature gradients; the edifice has been constructed at various rates and with variable distribution of effusive products. These intrinsic and extrinsic parameters are known to impact the rheological behaviour of rocks. Previous triaxial deformation studies on carbonates (Tavel Limestone, Solnhofen Limestone and Comiso Limestone) have shown the importance of temperature, and the presence of water as pore fluid, on the mechanical strength and failure mode of the rocks. However, to our knowledge, no previous studies have considered the distal heating effect of intrusions on the carbonate mechanical strength from the basement. Here we investigate the behaviour under varying P-T conditions at constant strain rate (10-5 s-1) on both dry and water saturated samples of Comiso Limestone, a low-porosity (10.2% average) carbonate rock belonging to the HP. We ran separate conventional triaxial experiments at various confining effective pressure from 0 up to 50 MPa at room temperature (20°C), in both dry and drained water-saturated conditions, using natural samples, and thermally-treated samples (150°C, 300°C, and 450°C). Acoustic Emissions and P-wave velocities were recorded during the experiments. Sample failure covers the brittle and

Rapid method to determine actinides and 89/90Sr in limestone and marble samples

International Nuclear Information System (INIS)

Maxwell, S.L.; Culligan, Brian; Hutchison, J.B.; Utsey, R.C.; Sudowe, Ralf; McAlister, D.R.

2016-01-01

A new method for the determination of actinides and radiostrontium in limestone and marble samples has been developed that utilizes a rapid sodium hydroxide fusion to digest the sample. Following rapid pre-concentration steps to remove sample matrix interferences, the actinides and 89 / 90 Sr are separated using extraction chromatographic resins and measured radiometrically. The advantages of sodium hydroxide fusion versus other fusion techniques will be discussed. This approach has a sample preparation time for limestone and marble samples of <4 h. (author)

Sodium sesquicarbonate (Akang) and limestone as catalysts for the ...

African Journals Online (AJOL)

Production of monoglycerides from palm and palm kernel oils were carried out using sodium sesquicarbonate (akang) and lime stone as catalysts.The results showed that the maximum monoglyceride formed is in the range of 49–57% of the fatty product for the limestone catalyst and 78 – 92% for the sodium ...

Limestone and oyster shell for brown layers in their second egg production cycle

Directory of Open Access Journals (Sweden)

CC Pizzolante

2011-06-01

Full Text Available This study aimed at evaluating the effect of dietary calcium levels and the replacement of calcium sources with different particle size compositions on the performance and egg quality of brown layers in their second egg production cycle. A randomized block experimental design was applied with 12 treatments in a 3x4 factorial arrangement: three calcium levels (2.6, 3.2, 3.8 % and four combinations of calcium sources (1- 100% fine limestone (FL, 2- 50% FL + 50% coarse limestone (CL, 3- 50% FL and 50% oyster shell (OS, 4- 50% FL and 25% CL+ 25 %OS, with six replicates of eight birds each. Calcium sources were analyzed for geometric mean diameter (GMD and in-vitro solubility. The following performance and egg quality parameters were evaluated: egg weight (EW, g, egg production (% Eggs, egg mass (EM %, feed intake (FI g, feed conversion ratio (FCR kg/dz and FCR kg/kg, mortality (% Mort., specific egg gravity (SG, percentages of yolk (Y%, albumen (Alb% and eggshell (ES%, eggshell thickness (EST, eggshell breaking strength (BS, eggshell weight per surface area (EWSA, Haugh unit (HU, yolk index (YI and yolk color. Performance and internal egg quality were not affected by the treatments (p>0.05. Blocks had a significant effect on (p<0.05 FI and FCR (kg/dz and kg/kg. Treatments significantly influenced external egg quality, which improved as dietary calcium levels increases and when up to 50% fine limestone was replaced by combinations of coarse limestone with oyster shell.

A NEW DAONELLA FROM THE LADINIAN PLATFORM OF THE ESINO LIMESTONE (SOUTHERN ALPS, ITALY

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CRISTIANO LARGHI

2006-03-01

Full Text Available The bivalve Daonella Mojsisovics, 1874 is very common in the Middle Triassic pelagic facies, whereas the record of this genus from shallow water limestones is rare. In the present paper a new species of Daonella, named D. pseudograbensis, is described from the Esino Limestone, a Ladinian (Middle Triassic carbonate platform in the central Southern Alps. The species is described from Brembana Valley, where the Esino Limestone is rather rich in bioclastic lenses yielding faunas with bivalves, cephalopods, gastropods, brachiopods, corals and calcareous algae. Daonella pseudograbensis n. sp. is based on very well preserved specimens, which are often articulated and closed, all coming from the same locality. The new species shows a narrow range of intraspecific and ontogenetic morphologic variations. It is easy distinguishable from the other species of the genus for the outline and ornamentation; it therefore differs from D. grabensis Kittl, 1912, the most similar species, for the longer anterior dorsal margin.Pdf

3D mapping of water in oolithic limestone at atmospheric and vacuum saturation using X-ray micro-CT differential imaging

Energy Technology Data Exchange (ETDEWEB)

Boone, M.A., E-mail: marijn.boone@ugent.be [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, 9000 Ghent (Belgium); Unit Sustainable Materials Management, VITO, Boerentang 200, 2400 Mol (Belgium); De Kock, T.; Bultreys, T. [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, 9000 Ghent (Belgium); De Schutter, G. [Magnel Laboratory for Concrete Research, Department of Structural Engineering, Ghent University, Technologiepark-Zwijnaarde 904, 9052 Ghent (Belgium); Vontobel, P. [Spallation Neutron Source Division, Paul Scherrer Institute (PSI), 5232 Villigen (Switzerland); Van Hoorebeke, L. [Department of Physics and Astronomy—UGCT, Ghent University, Proeftuinstraat 86, 9000 Ghent (Belgium); Cnudde, V. [Department of Geology and Soil Science—UGCT, Ghent University, Krijgslaan 281 S8, 9000 Ghent (Belgium)

2014-11-15

Determining the distribution of fluids in porous sedimentary rocks is of great importance in many geological fields. However, this is not straightforward, especially in the case of complex sedimentary rocks like limestone, where a multidisciplinary approach is often needed to capture its broad, multimodal pore size distribution and complex pore geometries. This paper focuses on the porosity and fluid distribution in two varieties of Massangis limestone, a widely used natural building stone from the southeast part of the Paris basin (France). The Massangis limestone shows locally varying post-depositional alterations, resulting in different types of pore networks and very different water distributions within the limestone. Traditional techniques for characterizing the porosity and pore size distribution are compared with state-of-the-art neutron radiography and X-ray computed microtomography to visualize the distribution of water inside the limestone at different imbibition conditions. X-ray computed microtomography images have the great advantage to non-destructively visualize and analyze the pore space inside of a rock, but are often limited to the larger macropores in the rock due to resolution limitations. In this paper, differential imaging is successfully applied to the X-ray computed microtomography images to obtain sub-resolution information about fluid occupancy and to map the fluid distribution in three dimensions inside the scanned limestone samples. The detailed study of the pore space with differential imaging allows understanding the difference in the water uptake behavior of the limestone, a primary factor that affects the weathering of the rock. - Highlights: • The water distribution in a limestone was visualized in 3D with micro-CT. • Differential imaging allowed to map both macro and microporous zones in the rock. • The 3D study of the pore space clarified the difference in water uptake behavior. • Trapped air is visualized in the moldic

[Effects of variable temperature on organic carbon mineralization in typical limestone soils].

Science.gov (United States)

Wang, Lian-Ge; Gao, Yan-Hong; Ding, Chang-Huan; Ci, En; Xie, De-Ti

2014-11-01

Soil sampling in the field and incubation experiment in the laboratory were conducted to investigate the responses of soil organic carbon (SOC) mineralization to variable temperature regimes in the topsoil of limestone soils from forest land and dry land. Two incubated limestone soils were sampled from the 0-10 cm layers of typical forest land and dry land respectively, which were distributed in Tianlong Mountain area of Puding county, Guizhou province. The soils were incubated for 56 d under two different temperature regimes including variable temperature (range: 15-25 degrees C, interval: 12 h) and constant temperature (20 degrees C), and the cumulative temperature was the same in the two temperature treatments. In the entire incubation period (56 d), the SOC cumulative mineralization (63.32 mg x kg(-1)) in the limestone soil from dry land (SH) under the variable temperature was lower than that (63.96 mg x kg(-1)) at constant 20 degrees C, and there was no significant difference in the SOC cumulative mineralization between the variable and constant temperature treatments (P variable temperature was significantly lower than that (209.52 mg x kg(-1)) at constant 20 degrees C. The results indicated that the responses of SOC mineralization to the variable temperature were obviously different between SL and SH soils. The SOC content and composition were significantly different between SL and SH soils affected by vegetation and land use type, which suggested that SOC content and composition were important factors causing the different responses of SOC mineralization to variable temperature between SL and SH soils. In addition, the dissolved organic carbon (DOC) content of two limestone soils were highly (P variable temperature mainly influenced SOC mineralization by changing microbial community activity rather than by changing microbial quantity.

Properties, sustainability and elevated temperature behavior of concrete containing Portland limestone cement

Science.gov (United States)

El-Hawary, Moetaz; Ahmed, Mahmoud

2017-09-01

The utilization of some type of cheap filler as partial cement replacement is an effective way of improving concrete sustainability. With the recent trends to reduce water to cement ratio and improve compaction, there is no enough space or water for complete hydration of cement. This means that actually, a portion of mixed cement acts as expensive filler. Replacing this portion with cheaper filler that requires less energy to produce is, therefore, beneficial. Crushed limestone is the most promising filler. This work is to investigate the effect of the amount of limestone fillers on the sustainability and the fresh and mechanical properties of the resulting concrete. A rich mix is designed with a low water/cement ratio of 0.4. Lime is introduced as a replacement percentage of cement. Ratios of 0, 10, 20 and 30% were used. Slump, compressive strength, specific gravity and water absorption are evaluated for every mix. In addition, the effect of the amount of lime on the residual strength of concrete subjected to elevated temperatures is also investigated. Samples are subjected to six different temperature stations of 20, 100, 200, 300, 500 and 700°C for six hours before being cooled and subsequently tested for compressive strength and specific gravity. Sustainability of the tested mixes is evaluated through reductions in the emitted carbon dioxide, energy and reduction in cost. Based on the annual use of concrete in Kuwait, the sustainability benefits resulting from the use of limestone filler in Kuwait are evaluated and assessed. The paper is concluded with the recommendation of the use of 15% limestone filler as partial cement replacement where the properties and the behavior under high temperature of the resulting concrete are almost the same as those of conventional concrete with considerable cost and sustainability benefits.

A correlation of Sr isotope stratigraphy and foraminiferal biostratigraphy in tertiary limestones of Papua New Guinea

International Nuclear Information System (INIS)

Allan, T.L.; Trotter, J.A.; Whitford, D.J.; Korsch, M.J.

2000-01-01

Strontium isotopic and stratigraphic data collected from the Darai Limestone of Papua New Guinea clearly demonstrate a systematic relationship between bulk 87 Sr/ 86 Sr ratio and index foraminiferal composition that closely reflects the relative stratigraphical range of the foraminifera in this region. A graphic correlation of stratigraphic, strontium isotopic and age ranges of the major index taxa permits direct evaluation of limestone age and isotopic composition in the Darai Limestone. The age of the Tf 1 /Tf 2 boundary (∼12.2 Ma) is significantly younger than the accepted estimate of ∼15.0 Ma (plankton Zone N9) and the Te/Tf boundary (∼20.3 Ma) is older than the generally accepted age of ∼l 8.5 Ma (plankton Zone N6)

Identification and characterization of near surface cavities in Tuwaiq Mountain Limestone, Riyadh, KSA, “detection and treatment”

Directory of Open Access Journals (Sweden)

Ahmed Abd El Aal

2017-03-01

Full Text Available This study evaluates the capability of surface electrical resistivity technique for identifying the weak zones or subsurface cavities in karst area with limestone rocks. Weak zones or cavities near surface can be potentially dangerous and several problems are associated with collapse of roads or buildings accompanied by subsidence phenomena. Karst environments are characterized by distinctive landforms, which are related to dissolution and dominant subsurface drainage. The interaction of limestone with water is able to create karst features such as cavity, pinnacle, boulder and sinkhole through the dissolution process. The existence of subsurface karst features are always a matter of concern to engineers before any development starts because these features could cause disaster in the future. The study was conducted at Tuwaiq Mountain Limestone, Riyadh region, KSA with the objective to detect and treat karst features at limestone rocks. The karst features such as fill cavity, boulder, pinnacle, discontinuity and overhang were detected in the survey lines. The 2-D ER results showed a good correlation with all the borehole records in determining the subsurface of limestone formation. The 2-D ER method is capable in mapping karst features and bedrock depth. The ability of the electrical technique to produce high resolution images of the subsurface, which are useful for subsidence assessment is illustrated.

Compositional characterization of French limestone: a new tool for art historians

International Nuclear Information System (INIS)

Holmes, L.L.; Harbottle, G.; Blanc, A.

1994-01-01

Limestone from quarries known to medieval craftsmen and from the monuments they built and embellished, as well as from carvings now in museum collections, has been characterized by neutron activation analysis. Specimens form 38 quarries in the Lutetian and Jurassic limestone formations of France and from sculptures in American and French museums have been tested, and the results have been compiled in a data base to which art historians may refer when attempting to determine provenance for sculptures. Multivariate statistical analysis of concentration data shows stone form a particular quarry in the Paris basin to be compositionally homogeneous and distinguishable from other quarries in the same formation. The same approach to data related to quarries near the Burgundian abbey of Cluny finds general agreement between classifications based on compositional and on petrographic data. (Author)

Intermediate-scale sodium-concrete reaction tests with basalt and limestone concrete

International Nuclear Information System (INIS)

Hassberger, J.A.; Muhlestein, L.D.

1981-01-01

Ten tests were performed to investigate the chemical reactions and rate and extent of attack between sodium and basalt and limestone concretes. Test temperatures ranged from 510 to 870 0 C (950 to 1600 0 F) and test times from 2 to 24 hours. Sodium hydroxide was added to some of the tests to assess the impact of a sodium hydroxide-aided reaction on the overall penetration characteristics. Data suggest that the sodium penetration of concrete surfaces is limited. Penetration of basalt concrete in the presence of sodium hydroxide is shown to be less severe than attack by the metallic sodium alone. Presence of sodium hydroxide changes the characteristics of sodium penetration of limestone concrete, but no major differences in bulk penetration were observed as compared to penetration by metallic sodium

An Interpretable Machine Learning Model for Accurate Prediction of Sepsis in the ICU.

Science.gov (United States)

Nemati, Shamim; Holder, Andre; Razmi, Fereshteh; Stanley, Matthew D; Clifford, Gari D; Buchman, Timothy G

2018-04-01

Sepsis is among the leading causes of morbidity, mortality, and cost overruns in critically ill patients. Early intervention with antibiotics improves survival in septic patients. However, no clinically validated system exists for real-time prediction of sepsis onset. We aimed to develop and validate an Artificial Intelligence Sepsis Expert algorithm for early prediction of sepsis. Observational cohort study. Academic medical center from January 2013 to December 2015. Over 31,000 admissions to the ICUs at two Emory University hospitals (development cohort), in addition to over 52,000 ICU patients from the publicly available Medical Information Mart for Intensive Care-III ICU database (validation cohort). Patients who met the Third International Consensus Definitions for Sepsis (Sepsis-3) prior to or within 4 hours of their ICU admission were excluded, resulting in roughly 27,000 and 42,000 patients within our development and validation cohorts, respectively. None. High-resolution vital signs time series and electronic medical record data were extracted. A set of 65 features (variables) were calculated on hourly basis and passed to the Artificial Intelligence Sepsis Expert algorithm to predict onset of sepsis in the proceeding T hours (where T = 12, 8, 6, or 4). Artificial Intelligence Sepsis Expert was used to predict onset of sepsis in the proceeding T hours and to produce a list of the most significant contributing factors. For the 12-, 8-, 6-, and 4-hour ahead prediction of sepsis, Artificial Intelligence Sepsis Expert achieved area under the receiver operating characteristic in the range of 0.83-0.85. Performance of the Artificial Intelligence Sepsis Expert on the development and validation cohorts was indistinguishable. Using data available in the ICU in real-time, Artificial Intelligence Sepsis Expert can accurately predict the onset of sepsis in an ICU patient 4-12 hours prior to clinical recognition. A prospective study is necessary to determine the

Effect of Limestone Powder on Microstructure of Ternary Cementitious System

NARCIS (Netherlands)

Zhang, Y.; Ye, G.

2012-01-01

The pressure to reach sustainability favours the development of ternary composite cement. The synergistic effect on mechanical behaviour at 28 days between limestone powder (LP) and pozzolanic additives, i.e. fly ash (FA) and blast furnace slag (BFS), has been documented. In order to better

Paleokarst processes in the Eocene limestones of the Pyramids Plateau, Giza, Egypt

Science.gov (United States)

El Aref, M. M.; Refai, E.

The Eocene limestones of the Pyramids plateau are characterized by landforms of stepped terraced escarpment and karst ridges with isolated hills. The carbonate country rocks are also dominated by minor surface, surface to subsurface and subsurface solution features associated with karst products. The systematic field observations eludicate the denudation trend of the minor solution features and suggest the origin of the regional landscapes. The lithologic and structural characters of the limestone country rocks comprise the main factors controlling the surface and subsurface karst evolution. The development of the karst features and the associated sediments in the study area provides information on the paleohydrolic, chemical and climatic environments involved in the origin of the karstification.

Development and Validation of a Multidisciplinary Tool for Accurate and Efficient Rotorcraft Noise Prediction (MUTE)

Science.gov (United States)

Liu, Yi; Anusonti-Inthra, Phuriwat; Diskin, Boris

2011-01-01

A physics-based, systematically coupled, multidisciplinary prediction tool (MUTE) for rotorcraft noise was developed and validated with a wide range of flight configurations and conditions. MUTE is an aggregation of multidisciplinary computational tools that accurately and efficiently model the physics of the source of rotorcraft noise, and predict the noise at far-field observer locations. It uses systematic coupling approaches among multiple disciplines including Computational Fluid Dynamics (CFD), Computational Structural Dynamics (CSD), and high fidelity acoustics. Within MUTE, advanced high-order CFD tools are used around the rotor blade to predict the transonic flow (shock wave) effects, which generate the high-speed impulsive noise. Predictions of the blade-vortex interaction noise in low speed flight are also improved by using the Particle Vortex Transport Method (PVTM), which preserves the wake flow details required for blade/wake and fuselage/wake interactions. The accuracy of the source noise prediction is further improved by utilizing a coupling approach between CFD and CSD, so that the effects of key structural dynamics, elastic blade deformations, and trim solutions are correctly represented in the analysis. The blade loading information and/or the flow field parameters around the rotor blade predicted by the CFD/CSD coupling approach are used to predict the acoustic signatures at far-field observer locations with a high-fidelity noise propagation code (WOPWOP3). The predicted results from the MUTE tool for rotor blade aerodynamic loading and far-field acoustic signatures are compared and validated with a variation of experimental data sets, such as UH60-A data, DNW test data and HART II test data.

Liquid carbon dioxide/pulverized limestone globulsion delivery system for deep ocean storage

Energy Technology Data Exchange (ETDEWEB)

Swett, P.; Golomb, D.; Barry, E.; Ryan, D.; Lawton, C. [Massachusetts Univ., Lowell, MA (United States)

2005-07-01

Ocean storage of carbon dioxide (CO{sub 2}) raises serious environmental, technical and economic problems because a massive point injection of pure liquid CO{sub 2} at depth would create a plume of carbonic acid with a pH lower than 7. Acidified seawater is considered to be harmful to aquatic organisms. Laboratory studies have shown that injecting a globulsion consisting of CO{sub 2}, water (H{sub 2}O) and calcium carbonate (CaCO{sub 3}) instead of pure liquid CO{sub 2} results in an alkaline reaction rather than an acidic reaction. Because calcium carbonate and bicarbonate are natural ingredients of seawater, there is no expected harm due to the additive limestone. This paper presented a practical delivery system for the underwater creation of globulsion. When liquid or supercritical CO{sub 2} is mixed with a slurry of finely pulverized limestone (CaCO{sub 3}) in pure or seawater, a macro-emulsion is formed consisting of CO{sub 2} droplets coated with CaCO{sub 3} particles dispersed in water. In this study, liquid CO{sub 2} was piped to approximately 500 m depth, which is below the flash point of liquid CO{sub 2} into vapor. A slurry of pulverized limestone in seawater was also separately piped to this depth. A static mixer was mounted at the end of the pipes. Liquid CO{sub 2}, along with a slurry of pulverized limestone and ambient seawater were pumped into the mixer by a turbine. The globulsion exited from the other end of the mixer and sank like a dense plume to greater depths while entraining ambient seawater. The CaCO{sub 3}-coated globules precipitated from the neutrally buoyant plume toward the ocean bottom following equilibration. As such, the ocean was not be acidified with this method of CO{sub 2} discharging. It was concluded that even inland seas, such as the Mediterranean and Black Seas, could be considered for sequestration of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} globulsion. Although adding pulverized limestone to liquid CO{sub 2} and the mixing

Effects of Diatomite–Limestone Powder Ratio on Mechanical and Anti-Deformation Properties of Sustainable Sand Asphalt Composite

Directory of Open Access Journals (Sweden)

Yongchun Cheng

2018-03-01

Full Text Available Diatomite has gained more and more interest as a new resource, since it has potential as a favorable alternative to mineral filler in the construction of asphalt pavement compared with ordinary limestone powder. In this paper, the mechanical and anti-deformation properties of sand asphalt composites with various proportions of diatomite were investigated by a uniaxial compression failure test, a uniaxial compression repeated creep test, and a low-temperature splitting test in order to determine the optimal replacement content of ordinary limestone powder. Five groups of sand asphalts with various volume ratios of diatomite to limestone (0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25, and 1:0 were determined by the simplex-lattice mixture design (SLD method. The results reveal that the compression strength, anti-deformation properties, and low-temperature crack resistance of sand asphalts are improved through the use of diatomite. Furthermore, the optimal ratio (0.327:0.673 of limestone to diatomite is determined by the SLD method, according to secant modulus and creep strain results.

Accurate First-Principles Spectra Predictions for Planetological and Astrophysical Applications at Various T-Conditions

Science.gov (United States)

Rey, M.; Nikitin, A. V.; Tyuterev, V.

2014-06-01

Knowledge of near infrared intensities of rovibrational transitions of polyatomic molecules is essential for the modeling of various planetary atmospheres, brown dwarfs and for other astrophysical applications 1,2,3. For example, to analyze exoplanets, atmospheric models have been developed, thus making the need to provide accurate spectroscopic data. Consequently, the spectral characterization of such planetary objects relies on the necessity of having adequate and reliable molecular data in extreme conditions (temperature, optical path length, pressure). On the other hand, in the modeling of astrophysical opacities, millions of lines are generally involved and the line-by-line extraction is clearly not feasible in laboratory measurements. It is thus suggested that this large amount of data could be interpreted only by reliable theoretical predictions. There exists essentially two theoretical approaches for the computation and prediction of spectra. The first one is based on empirically-fitted effective spectroscopic models. Another way for computing energies, line positions and intensities is based on global variational calculations using ab initio surfaces. They do not yet reach the spectroscopic accuracy stricto sensu but implicitly account for all intramolecular interactions including resonance couplings in a wide spectral range. The final aim of this work is to provide reliable predictions which could be quantitatively accurate with respect to the precision of available observations and as complete as possible. All this thus requires extensive first-principles quantum mechanical calculations essentially based on three necessary ingredients which are (i) accurate intramolecular potential energy surface and dipole moment surface components well-defined in a large range of vibrational displacements and (ii) efficient computational methods combined with suitable choices of coordinates to account for molecular symmetry properties and to achieve a good numerical

Discontinuity surfaces and event stratigraphy of Okha Shell Limestone Member: Implications for Holocene sea level changes, western India

Science.gov (United States)

Bhonde, Uday; Desai, Bhawanisingh G.

2011-08-01

The Okha Shell Limestone Member of Chaya Formation is the coarse grained, shell rich deposit commonly recognized as the beach rocks. It has been age bracketed between Late Pleistocene and Holocene. Late Quaternary sea level changes have been studied with beach rocks along the Saurashtra coastal region. The present study has been carried out in the Okhamandal area of the Saurashtra peninsula especially on the Okha Shell Limestone Member as exposed at various locations along the coast from north to south. Temporal and spatial correlations of the observations have revealed three events in the Okha Shell Limestone Member of Chaya Formation that are correlated laterally. The events show depositional breaks represented by discontinuity surfaces, the taphofacies varieties and ichnological variations. The present study in the context of available geochrnological data of the region suggests a prominent depositional break representing low sea level stand (regression) during an Early Holocene during the deposition of Okha Shell Limestone Member.

Comparison of Limestone and Ground Fish for Treatment of Nutritional Rickets in Children in Nigeria.

Science.gov (United States)

Thacher, Tom D; Bommersbach, Tanner J; Pettifor, John M; Isichei, Christian O; Fischer, Philip R

2015-07-01

To determine whether children with calcium-deficiency rickets respond better to treatment with calcium as limestone or as ground fish. Nigerian children with active rickets (n = 96) were randomized to receive calcium as powdered limestone (920 mg of elemental calcium) or ground fish (952 mg of elemental calcium) daily for 24 weeks. Radiographic healing was defined as achieving a score of 1.5 or less on a 10-point scale. The median (range) age of enrolled children was 35 (6-151) months. Of the 88 children who completed the study, 29 (66%) in the ground fish group and 24 (55%) in the limestone group achieved the primary outcome of a radiographic score of 1.5 or less within 6 months (P = .39). The mean radiographic score improved from 6.2 ± 2.4 to 1.8 ± 2.2 in the ground fish group and from 6.3 ± 2.2 to 2.1 ± 2.4 in the limestone group (P = .68 for group comparison). In an intention to treat analysis adjusted for baseline radiographic score, age, milk calcium intake, and serum 25-hydroxyvitamin D concentration, the response to treatment did not differ between the 2 groups (P = .39). Younger age was associated with more complete radiographic healing in the adjusted model (aOR 0.74 [95% CI 0.57-0.92]). After 24 weeks of treatment, serum alkaline phosphatase had decreased, calcium and 25-hydroxyvitamin D increased, and bone mineral density increased in both groups, without significant differences between treatment groups. In children with calcium-deficiency rickets, treatment with calcium as either ground fish or limestone for 6 months healed rickets in the majority of children. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Evaluation of Different Modeling Approaches to Simulate Contaminant Transport in a Fractured Limestone Aquifer

Science.gov (United States)

Mosthaf, K.; Rosenberg, L.; Balbarini, N.; Broholm, M. M.; Bjerg, P. L.; Binning, P. J.

2014-12-01

It is important to understand the fate and transport of contaminants in limestone aquifers because they are a major drinking water resource. This is challenging because they are highly heterogeneous; with micro-porous grains, flint inclusions, and being heavily fractured. Several modeling approaches have been developed to describe contaminant transport in fractured media, such as the discrete fracture (with various fracture geometries), equivalent porous media (with and without anisotropy), and dual porosity models. However, these modeling concepts are not well tested for limestone geologies. Given available field data and model purpose, this paper therefore aims to develop, examine and compare modeling approaches for transport of contaminants in fractured limestone aquifers. The model comparison was conducted for a contaminated site in Denmark, where a plume of a dissolved contaminant (PCE) has migrated through a fractured limestone aquifer. Multilevel monitoring wells have been installed at the site and available data includes information on spill history, extent of contamination, geology and hydrogeology. To describe the geology and fracture network, data from borehole logs was combined with an analysis of heterogeneities and fractures from a nearby excavation (analog site). Methods for translating the geological information and fracture mapping into each of the model concepts were examined. Each model was compared with available field data, considering both model fit and measures of model suitability. An analysis of model parameter identifiability and sensitivity is presented. Results show that there is considerable difference between modeling approaches, and that it is important to identify the right one for the actual scale and model purpose. A challenge in the use of field data is the determination of relevant hydraulic properties and interpretation of aqueous and solid phase contaminant concentration sampling data. Traditional water sampling has a bias

A New Approach for Accurate Prediction of Liquid Loading of Directional Gas Wells in Transition Flow or Turbulent Flow

Directory of Open Access Journals (Sweden)

Ruiqing Ming

2017-01-01

Full Text Available Current common models for calculating continuous liquid-carrying critical gas velocity are established based on vertical wells and laminar flow without considering the influence of deviation angle and Reynolds number on liquid-carrying. With the increase of the directional well in transition flow or turbulent flow, the current common models cannot accurately predict the critical gas velocity of these wells. So we built a new model to predict continuous liquid-carrying critical gas velocity for directional well in transition flow or turbulent flow. It is shown from sensitivity analysis that the correction coefficient is mainly influenced by Reynolds number and deviation angle. With the increase of Reynolds number, the critical liquid-carrying gas velocity increases first and then decreases. And with the increase of deviation angle, the critical liquid-carrying gas velocity gradually decreases. It is indicated from the case calculation analysis that the calculation error of this new model is less than 10%, where accuracy is much higher than those of current common models. It is demonstrated that the continuous liquid-carrying critical gas velocity of directional well in transition flow or turbulent flow can be predicted accurately by using this new model.

Accurate and dynamic predictive model for better prediction in medicine and healthcare.

Science.gov (United States)

Alanazi, H O; Abdullah, A H; Qureshi, K N; Ismail, A S

2018-05-01

Information and communication technologies (ICTs) have changed the trend into new integrated operations and methods in all fields of life. The health sector has also adopted new technologies to improve the systems and provide better services to customers. Predictive models in health care are also influenced from new technologies to predict the different disease outcomes. However, still, existing predictive models have suffered from some limitations in terms of predictive outcomes performance. In order to improve predictive model performance, this paper proposed a predictive model by classifying the disease predictions into different categories. To achieve this model performance, this paper uses traumatic brain injury (TBI) datasets. TBI is one of the serious diseases worldwide and needs more attention due to its seriousness and serious impacts on human life. The proposed predictive model improves the predictive performance of TBI. The TBI data set is developed and approved by neurologists to set its features. The experiment results show that the proposed model has achieved significant results including accuracy, sensitivity, and specificity.

Laboratory study of SO2 dry deposition on limestone and marble: Effects of humidity and surface variables

Science.gov (United States)

Spiker, E. C.; Hosker, R.P.; Weintraub, V.C.; Sherwood, S.I.

1995-01-01

The dry deposition of gaseous air pollutants on stone and other materials is influenced by atmospheric processes and the chemical characteristics of the deposited gas species and of the specific receptor material. Previous studies have shown that relative humidity, surface moisture, and acid buffering capability of the receptor surface are very important factors. To better quantify this behavior, a special recirculating wind tunnel/environmental chamber was constructed, in which wind speed, turbulence, air temperature, relative humidity, and concentrations of several pollutants (SO2, O3, nitrogen oxides) can be held constant. An airfoil sample holder holds up to eight stone samples (3.8 cm in diameter and 1 cm thick) in nearly identical exposure conditions. SO2 deposition on limestone was found to increase exponentially with increasing relative humidity (RH). Marble behaves similarly, but with a much lower deposition rate. Trends indicate there is little deposition below 20% RH on clean limestone and below 60% RH on clean marble. This large difference is due to the limestone's greater porosity, surface roughness, and effective surface area. These results indicate surface variables generally limit SO2 deposition below about 70% RH on limestone and below at least 95% RH on marble. Aerodynamic variables generally limit deposition at higher relative humidity or when the surface is wet.The dry deposition of gaseous air pollutants on stone and other materials is influenced by atmospheric processes and the chemical characteristics of the deposited gas species and of the specific receptor material. Previous studies have shown that relative humidity, surface moisture, and acid buffering capability of the receptor surface are very important factors. To better quantify this behavior, a special recirculating wind tunnel/environmental chamber was constructed, in which wind speed, turbulence, air temperature, relative humidity, and concentrations of several pollutants (SO2, O3

Accurate prediction of severe allergic reactions by a small set of environmental parameters (NDVI, temperature).

Science.gov (United States)

Notas, George; Bariotakis, Michail; Kalogrias, Vaios; Andrianaki, Maria; Azariadis, Kalliopi; Kampouri, Errika; Theodoropoulou, Katerina; Lavrentaki, Katerina; Kastrinakis, Stelios; Kampa, Marilena; Agouridakis, Panagiotis; Pirintsos, Stergios; Castanas, Elias

2015-01-01

Severe allergic reactions of unknown etiology,necessitating a hospital visit, have an important impact in the life of affected individuals and impose a major economic burden to societies. The prediction of clinically severe allergic reactions would be of great importance, but current attempts have been limited by the lack of a well-founded applicable methodology and the wide spatiotemporal distribution of allergic reactions. The valid prediction of severe allergies (and especially those needing hospital treatment) in a region, could alert health authorities and implicated individuals to take appropriate preemptive measures. In the present report we have collecterd visits for serious allergic reactions of unknown etiology from two major hospitals in the island of Crete, for two distinct time periods (validation and test sets). We have used the Normalized Difference Vegetation Index (NDVI), a satellite-based, freely available measurement, which is an indicator of live green vegetation at a given geographic area, and a set of meteorological data to develop a model capable of describing and predicting severe allergic reaction frequency. Our analysis has retained NDVI and temperature as accurate identifiers and predictors of increased hospital severe allergic reactions visits. Our approach may contribute towards the development of satellite-based modules, for the prediction of severe allergic reactions in specific, well-defined geographical areas. It could also probably be used for the prediction of other environment related diseases and conditions.

A Machine Learned Classifier That Uses Gene Expression Data to Accurately Predict Estrogen Receptor Status

Science.gov (United States)

Bastani, Meysam; Vos, Larissa; Asgarian, Nasimeh; Deschenes, Jean; Graham, Kathryn; Mackey, John; Greiner, Russell

2013-01-01

Background Selecting the appropriate treatment for breast cancer requires accurately determining the estrogen receptor (ER) status of the tumor. However, the standard for determining this status, immunohistochemical analysis of formalin-fixed paraffin embedded samples, suffers from numerous technical and reproducibility issues. Assessment of ER-status based on RNA expression can provide more objective, quantitative and reproducible test results. Methods To learn a parsimonious RNA-based classifier of hormone receptor status, we applied a machine learning tool to a training dataset of gene expression microarray data obtained from 176 frozen breast tumors, whose ER-status was determined by applying ASCO-CAP guidelines to standardized immunohistochemical testing of formalin fixed tumor. Results This produced a three-gene classifier that can predict the ER-status of a novel tumor, with a cross-validation accuracy of 93.17±2.44%. When applied to an independent validation set and to four other public databases, some on different platforms, this classifier obtained over 90% accuracy in each. In addition, we found that this prediction rule separated the patients' recurrence-free survival curves with a hazard ratio lower than the one based on the IHC analysis of ER-status. Conclusions Our efficient and parsimonious classifier lends itself to high throughput, highly accurate and low-cost RNA-based assessments of ER-status, suitable for routine high-throughput clinical use. This analytic method provides a proof-of-principle that may be applicable to developing effective RNA-based tests for other biomarkers and conditions. PMID:24312637

Hydrobiogeochemical interactions in 'anoxic' limestone drains for neutralization of acidic mine drainage

Science.gov (United States)

Robbins, E.I.; Cravotta, C.A.; Savela, C.E.; Nord, G.L.

1999-01-01

Processes affecting neutralization of acidic coal mine drainage were evaluated within 'anoxic' limestone drains (ALDs). Influents had pH???3.5 and dissolved oxygen Al3+ and Fe3+ compounds. Cleavage mounts of calcite and gypsum that were suspended within the ALDs and later examined microscopically showed dissolution features despite coatings by numerous bacteria, biofilms, and Fe-Al-Si precipitates. In the drain exhibiting the greatest flow reduction, Al-hydroxysulfates had accumulated on limestone surfaces and calcite etch points, thus causing the decline in transmissivity and dissolution. Therefore, where Al loadings are high and flow rates are low, a pre-treatment step is indicated to promote Al removal before diverting acidic mine water into alkalinity-producing materials. ?? 1998 Elsevier Science Ltd.

Incorporating full-scale experience into advanced limestone wet FGD designs

International Nuclear Information System (INIS)

Rader, P.C.; Bakke, E.

1992-01-01

Utilities choosing flue gas desulfurization as a strategy for compliance with Phase I of the 1990 Clean Air Act Amendments will largely turn to limestone wet scrubbing as the most cost-effective, least-risk option. State-of-the-art single absorber wet scrubbing systems can be designed to achieve: SO 2 removal efficiencies in excess of 95 %, system availabilities in excess of 98%, and byproducts which can be marketed or land filled. As a result of varying fuel characteristics, site considerations, and owner preferences, FGD plants for large central power stations are typically custom-designed. To avoid the risks associated with new, first-of-a-kind technologies, utilities have preferred to purchase FGD systems from suppliers with proven utility experience and reference plants as close as possible to the design envisioned. As the market for FGD systems is regulatory driven, the demand has shifted geographically in response to national environmental policies. Although limestone wet scrubbing has emerged as the overwhelming choice for SO 2 emission control in coal-fired power stations, the technology has evolved and been adapted to suit local and regional technical and economic situations. Global suppliers are able to benefit from experience and technological advances in the world market. With market units in the U.S., Denmark, Italy, Sweden, and Germany active in the design and supply of wet FGD plants, ABB has a unique ability to incorporate knowledge and experience gained throughout the industrialized world to acid rain retrofit projects in the U.S. This paper describes the design of advanced limestone wet scrubbing systems for application to acid rain retrofits. Specifically, the evolution of advanced design concepts from a global experience base is discussed

Accurate bearing remaining useful life prediction based on Weibull distribution and artificial neural network

Science.gov (United States)

Ben Ali, Jaouher; Chebel-Morello, Brigitte; Saidi, Lotfi; Malinowski, Simon; Fnaiech, Farhat

2015-05-01

Accurate remaining useful life (RUL) prediction of critical assets is an important challenge in condition based maintenance to improve reliability and decrease machine's breakdown and maintenance's cost. Bearing is one of the most important components in industries which need to be monitored and the user should predict its RUL. The challenge of this study is to propose an original feature able to evaluate the health state of bearings and to estimate their RUL by Prognostics and Health Management (PHM) techniques. In this paper, the proposed method is based on the data-driven prognostic approach. The combination of Simplified Fuzzy Adaptive Resonance Theory Map (SFAM) neural network and Weibull distribution (WD) is explored. WD is used just in the training phase to fit measurement and to avoid areas of fluctuation in the time domain. SFAM training process is based on fitted measurements at present and previous inspection time points as input. However, the SFAM testing process is based on real measurements at present and previous inspections. Thanks to the fuzzy learning process, SFAM has an important ability and a good performance to learn nonlinear time series. As output, seven classes are defined; healthy bearing and six states for bearing degradation. In order to find the optimal RUL prediction, a smoothing phase is proposed in this paper. Experimental results show that the proposed method can reliably predict the RUL of rolling element bearings (REBs) based on vibration signals. The proposed prediction approach can be applied to prognostic other various mechanical assets.

Studies on the effects of air pollution on limestone degradation in Great Britain

Science.gov (United States)

Webb, A. H.; Bawden, R. J.; Busby, A. K.; Hopkins, J. N.

solubility of limestone in water was the dominant term in describing the stone loss, and neutralization of the rainfall acidity the least significant. The volume of the intercepted rainfall and the variation in the pH of the run-off water with rainfall intensity have been identified as the two most significant terms which require more precise quantification. The data from the inland fumigation site used in the model predict a stone loss due to sulphur dioxide in the air of less than 1 μm yr -1 surface recession per ppb SO 2.

The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

Energy Technology Data Exchange (ETDEWEB)

Montagnaro, Fabio [Dipartimento di Chimica - Universita degli Studi di Napoli Federico II, Complesso Universitario del Monte di Sant' Angelo, 80126 Napoli (Italy); Salatino, Piero [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Scala, Fabrizio [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy)

2010-04-15

The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination. This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)

Assessment of brittleness and empirical correlations between physical and mechanical parameters of the Asmari limestone in Khersan 2 dam site, in southwest of Iran

Science.gov (United States)

Lashkaripour, Gholam Reza; Rastegarnia, Ahmad; Ghafoori, Mohammad

2018-02-01

The determination of brittleness and geomechanical parameters, especially uniaxial compressive strength (UCS) and Young's modulus (ES) of rocks are needed for the design of different rock engineering applications. Evaluation of these parameters are time-consuming processes, tedious, expensive and require well-prepared rock cores. Therefore, compressional wave velocity (Vp) and index parameters such as point load index and porosity are often used to predict the properties of rocks. In this paper, brittleness and other properties, physical and mechanical in type, of 56 Asmari limestones in dry and saturated conditions were analyzed. The rock samples were collected from Khersan 2 dam site. This dam with the height of 240 m is being constructed and located in the Zagros Mountain, in the southwest of Iran. The bedrock and abutments of the dam site consist of Asemari and Gachsaran Formations. In this paper, a practical relation for predicting brittleness and some relations between mechanical and index parameters of the Asmari limestone were established. The presented equation for predicting brittleness based on UCS, Brazilian tensile strength and Vp had high accuracy. Moreover, results showed that the brittleness estimation based on B3 concept (the ratio of multiply compressive strength in tensile strength divided 2) had more accuracy as compared to the B2 (the ratio of compressive strength minus tensile strength to compressive strength plus tensile strength) and B1 (the ratio of compressive strength to tensile strength) concepts.

Measuring solar reflectance - Part I: Defining a metric that accurately predicts solar heat gain

Energy Technology Data Exchange (ETDEWEB)

Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul [Heat Island Group, Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

2010-09-15

Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective ''cool colored'' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland US latitudes, this metric R{sub E891BN} can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {<=} 5:12 [23 ]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool roof net energy savings by as much as 23%. We define clear sky air mass one global horizontal (''AM1GH'') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer. (author)

Measuring solar reflectance Part I: Defining a metric that accurately predicts solar heat gain

Energy Technology Data Exchange (ETDEWEB)

Levinson, Ronnen; Akbari, Hashem; Berdahl, Paul

2010-05-14

Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective 'cool colored' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland U.S. latitudes, this metric RE891BN can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {le} 5:12 [23{sup o}]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool-roof net energy savings by as much as 23%. We define clear-sky air mass one global horizontal ('AM1GH') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} is well suited to rating the solar reflectances of roofs, pavements and walls. We show in Part II that R{sub g,0} can be easily and accurately measured with a pyranometer, a solar spectrophotometer or version 6 of the Solar Spectrum Reflectometer.

Experienced materials in wet limestone-gypsum FGD system

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, S. [Mitsubishi Heavy Industry, Hiroshima (Japan). Hiroshima Research and Development Center; Iwashita, K.; Ochi, E.; Higuchi, T. [Mitsubishi heavy Industry, Yokohama (Japan)

1998-12-31

This study was made on the corrosion resistivity evaluation method used for material selection in the Wet Limestone-Gypsum FGD system with examples of various process configuration, their corrosion environment, and the materials used in them. The wet limestone-gypsum process FGD plant is broadly divided into two types-ash-separated (dual-loop) process, and ash-mixed (single-loop) process-depending on whether the flue gas is separated from ash before being led into the absorber or led as it is into the absorber mixed with ash. Presently, the single-loop process has become the mainstream process however. The dual -loop process comprises a dedusting tower (quencher) and an absorption tower (absorber). In the quencher ash is removed with sprayed water where most of the HCl, HF etc., and a part of SO{sub x} and NO{sub x} contained in the flue gas are also removed with absorption. On the contrary, in the single-loop process which is configured of only the absorber, the flue gas is introduced into it as it is contained with ash, SO{sub x}, NO{sub x}, HCl, HF etc. The corrosion environment in these plants largely differs depending on the process type and condition. The absorber recirculated liquid has various ion inclusions among which Cl{sup {minus}} promotes pitting corrosion and crevice corrosion while SO{sub 4}{sup 2{minus}} inhibits these corrosions. Both Cl{sup {minus}} and SO{sub 4}{sup 2{minus}} cover an extremely large range between 25 to 100,000 ppm and 564 to 73,600 ppm respectively, and their influence on the corrosion is related to their activity which is decided by Ca{sup 2+}, Mg{sup 2+}, Na{sup +}, NH{sub 4}{sup +}, H{sup +} and liquid temperature. The balance of these ions is decided by the gas composition, limestone composition, make-up water and wastewater mass balance etc., of individual plants. Accordingly, materials of FGD plant are selected on the basis of evaluated results of corrosion resistivity test made under such simulated process conditions of

Size matters. The width and location of a ureteral stone accurately predict the chance of spontaneous passage

Energy Technology Data Exchange (ETDEWEB)

Jendeberg, Johan; Geijer, Haakan; Alshamari, Muhammed; Liden, Mats [Oerebro University Hospital, Department of Radiology, Faculty of Medicine and Health, Oerebro (Sweden); Cierzniak, Bartosz [Oerebro University, Department of Surgery, Faculty of Medicine and Health, Oerebro (Sweden)

2017-11-15

To determine how to most accurately predict the chance of spontaneous passage of a ureteral stone using information in the diagnostic non-enhanced computed tomography (NECT) and to create predictive models with smaller stone size intervals than previously possible. Retrospectively 392 consecutive patients with ureteric stone on NECT were included. Three radiologists independently measured the stone size. Stone location, side, hydronephrosis, CRP, medical expulsion therapy (MET) and all follow-up radiology until stone expulsion or 26 weeks were recorded. Logistic regressions were performed with spontaneous stone passage in 4 weeks and 20 weeks as the dependent variable. The spontaneous passage rate in 20 weeks was 312 out of 392 stones, 98% in 0-2 mm, 98% in 3 mm, 81% in 4 mm, 65% in 5 mm, 33% in 6 mm and 9% in ≥6.5 mm wide stones. The stone size and location predicted spontaneous ureteric stone passage. The side and the grade of hydronephrosis only predicted stone passage in specific subgroups. Spontaneous passage of a ureteral stone can be predicted with high accuracy with the information available in the NECT. We present a prediction method based on stone size and location. (orig.)

Modelling of catalytic oxidation of NH3 and reduction of NO on limestone during sulphur capture

DEFF Research Database (Denmark)

Kiil, Søren; Bhatia, Suresh K.; Dam-Johansen, Kim

1996-01-01

activity with respect to each species involved. An existing particle model, the Grain-Micrograin Model, which simulates sulphur capture on limestone under oxidizing conditions is considered in the modelling. Simulation results in good qualitative agreement with experimental data are obtained here......A theoretical study of the complex transient system of simultaneous sulphur capture and catalytic reactions of N-containing compounds taking place on a single limestone particle is conducted. The numerical technique developed previously by the authors (Kiil et al. 1994) based on collocation...... for the catalytic chemistry of NH3 during simultaneous sulphur capture on a Stevns Chalk particle. The reduction of NO by NH3 over CaSO4 (which is the product of the reaction between SO2, O2 and limestone) was found to be important because this reaction could explain the change in selectivity with increased solid...

The effect of water on the sulphation of limestone

Energy Technology Data Exchange (ETDEWEB)

Chunbo Wang; Lufei Jia; Yewen Tan; E.J. Anthony [North China Electric Power University, Baoding City (China). School of Energy and Power Engineering

2010-09-15

A series of tests was conducted in a thermogravimetric analyzer (TGA) to study the sulphation behaviour of limestone in the presence of water over the temperature range of 800-850{sup o}C. Four different Canadian limestones, all with a particle size range of 75-425 {mu}m, were sulphated using a synthetic flue gas with a composition of 15% CO{sub 2}, 3% O{sub 2}, 0% or 10% H{sub 2}O, 1750 ppm SO{sub 2} and the balance N{sub 2}. Water was shown to have a significant promotional effect on sulphation, especially in the diffusion-controlled stage. However, the effect of water during the kinetic-controlled stage appeared to be much less pronounced. Based on these results, it is proposed that the presence of water leads to the transient formation of Ca(OH){sub 2} as an intermediate, which in turn reacts with SO{sub 2} at a faster rate than CaO does. Alternatively stated, it appears that H{sub 2}O acts as catalyst for the sulphation reaction of CaO. 30 refs., 8 figs., 3 tabs.

Fault-related dolomitization in the Vajont Limestone (Southern Alps, Italy): photogrammetric 3D outcrop reconstruction, visualization with textured surfaces, and structural analysis

OpenAIRE

Bistacchi, Andrea; Balsamo, Fabrizio; Storti, Fabrizio; Mozafari, Mahtab; Swennen, Rudy; Solum, John; Taberner, Conxita

2013-01-01

The Vajont Gorge (Dolomiti Bellunesi, Italy) provides spectacular outcrops of Jurassic limestones (Vajont Limestone Formation) in which Mesozoic and Alpine faults and fracture corridors are continuously exposed. Some of these faults acted as conduits for fluids, resulting in structurally-controlled dolomitization of the Vajont Limestone, associated with significant porosity increase. We carried out a 3D surface characterization of the outcrops, combining high resolution topography and imaging...

Detecting change in water quality from implementation of limestone treatment systems in a coal-minded watershed

Science.gov (United States)

Cravotta,, Charles A.; Weitzel, Jeffrey B.

2000-01-01

During 1996-97, a variety of limestone-based treatment systems were implemented to neutralize acidic mine drainage and reduce the transport of dissolved metals in the northern part of the Swatara Creek watershed, which drains a 43-mi2 (112-km2) area in the Southern Anthracite Field upstream from Ravine, Pa. Since 1996, the current project has monitored water quality upstream and downstream of each treatment and at integrator sites on lower reaches of Swatara Creek. Continuous measurements of pH and specific conductance and periodic sampling for alkalinity, acidity, sulfate, and metals upstream and downstream of each treatment system show that (1) open limestone channels and limestone-sand dosing generally had negligible effects on water quality and (2) limestone diversion wells and limestone drains generally were effective at producing near-neutral pH and attenuating dissolved metals during baseflow but were less effective during stormflow conditions. Storm runoff in this area commonly is acidic, and, as streamflow volume increases during stormflow conditions, a smaller fraction of total flow is treated and (or) residence time in the treatment system is reduced. Monitoring on the mainstem of Swatara Creek indicates watershed-scale effects owing primarily to changes in mining practices and secondarily to watershed-wide implementation of treatment systems. Most underground mines in the Swatara Creek Basin were abandoned before 1960 and are presently flooded. Drainage from these mines contributes substantially to baseflow in Swatara Creek. For Swatara Creek at Ravine, Pa., which is immediately downstream of the mined area, long-term data collected since 1959 indicate sulfate concentration declined from about 150 mg/L in 1959 to 75 mg/L in 1999; pH increased sharply from 3.5-4.4 (median ~4) to 4.6-7.0 (median ~6) after 1975. These trends resulted from a decline in pyrite oxidation and the onset of carbonate buffering. Because these long-term attenuation processes have

Kinetic Study of Calcination of Jakura Limestone Using Power Rate ...

African Journals Online (AJOL)

The calcination of Jakura limestone was also found to be first order reaction with respect to CaCO3 concentration having average regression coefficient of 0.99. The temperature dependent terms were found using Arrhenius law and it was observed that the reaction temperature has a direct effect on the rate of reaction.

Moisture distribution in the stone portal of a church: how it influences the salt accumulation in porous limestone

Science.gov (United States)

Török, Ákos; Galambos, Éva

2017-04-01

Mathias Church of Budapest (Hungary) is an emblematic stone monument that represents various phases of constructions from Medieval period to the early 20th century. The church is found at the elevated Castle Hill and forms a landmark at the UNESCO World Heritage Site of Budapest. Its main construction material is porous Miocene limestone. Besides porous limestone travertine was also extensively used. The current study focuses on the Medieval Gate of the church which encompasses richly decorated porous limestone ornaments. The gate is now sheltered and form an interior portal of the church. It shows various forms of stone decay. The most striking one is efflorescence of salts. This feature has become more intense in the past years leading to flaking and granular disintegration of the limestone, causing damage to the monument. This study focuses on the detection of moisture content within the stone structure and its role in the salt accumulation. To obtain this goal in situ moisture measurements were made along vertical profiles by a portable moisture detector (Gann-Hydromette). It allowed outlining the moisture distribution within the studied structure. The moisture measurement was combined with sampling of salt efflorescence and porous limestone of the gate, itself. The samples were tested by optical microscopy. Conductivity, salt content and main elements were also detected from solutions. Mineralogical composition was recorded by XRD and Thermogravimetric analyses. Magnesium-sulphates were found to be the main salts responsible for damages. Besides sulphates chlorides were also detected. Gypsum was also found in the weathering crusts of the previously exposed limestone surfaces. It accumulated in black crusts but was also detected in white efflorescence and below the stone surface. The salt distribution clearly correlates with the moisture content. The financial support of NKFI Fund (ref. no. K 116532) is appreciated.

Morphological Changes of Limestone Sorbent Particles during Carbonation/Calcination Looping Cycles in a Thermogravimetric Analyzer (TGA) and Reactivation with Steam

KAUST Repository

Wu, Y.

2010-04-15

Carbonation and calcination looping cycles were carried out on four limestones in a thermogravimetric analyzer (TGA). The CO2 carrying capacity of a limestone particle decays very quickly in the first 10 cycles, reducing to about 20% of its original uptake capacity after 10 cycles for the four limestones studied in this work, and it decreases further to 6-12% after 50 cycles. A new steam reactivation method was applied on the spent sorbent to recover the loss of reactivity. The steam reactivation of multi-cycled samples was conducted at atmospheric pressure. Steam reactivation for 5 min at 130 °C of particles that had undergone 10 cycles resulted in an immediate increase (by 45-60% points) in carrying capacity. The morphological changes of limestone particles during the cycling and steam reactivation were studied using both an optical microscope and scanning electron microscopy (SEM). The diameters of limestone particles shrank by about 2-7% after 10 carbonation/calcination cycles, and the particle diameters swelled significantly (12-22% increase) after steam reactivation. These size changes are important for studies of attrition and mathematical modeling of carbonation. © 2010 American Chemical Society.

An Extrapolation of a Radical Equation More Accurately Predicts Shelf Life of Frozen Biological Matrices.

Science.gov (United States)

De Vore, Karl W; Fatahi, Nadia M; Sass, John E

2016-08-01

Arrhenius modeling of analyte recovery at increased temperatures to predict long-term colder storage stability of biological raw materials, reagents, calibrators, and controls is standard practice in the diagnostics industry. Predicting subzero temperature stability using the same practice is frequently criticized but nevertheless heavily relied upon. We compared the ability to predict analyte recovery during frozen storage using 3 separate strategies: traditional accelerated studies with Arrhenius modeling, and extrapolation of recovery at 20% of shelf life using either ordinary least squares or a radical equation y = B1x(0.5) + B0. Computer simulations were performed to establish equivalence of statistical power to discern the expected changes during frozen storage or accelerated stress. This was followed by actual predictive and follow-up confirmatory testing of 12 chemistry and immunoassay analytes. Linear extrapolations tended to be the most conservative in the predicted percent recovery, reducing customer and patient risk. However, the majority of analytes followed a rate of change that slowed over time, which was fit best to a radical equation of the form y = B1x(0.5) + B0. Other evidence strongly suggested that the slowing of the rate was not due to higher-order kinetics, but to changes in the matrix during storage. Predicting shelf life of frozen products through extrapolation of early initial real-time storage analyte recovery should be considered the most accurate method. Although in this study the time required for a prediction was longer than a typical accelerated testing protocol, there are less potential sources of error, reduced costs, and a lower expenditure of resources. © 2016 American Association for Clinical Chemistry.

Soil-gas diffusivity fingerprints of the dual porosity system in fractured limestone

DEFF Research Database (Denmark)

Claes, Niels; Chamindu, D.T.K.K.; Jensen, Jacob Birk

2010-01-01

processes are mostly limited to hydrogeological (water and solute) transport studies with very poor attention to the gaseous phase transport studies (Kristensen et al. 2010). This study characterizes fractured limestone soils for gas diffusion based on three different gas diffusivity fingerprints. The first...... fingerprint is a two-parameter exponential model, which mainly describes the gas diffusivity in the limestone matrix while taking both fracture connectivity and matrix pore connectivity into account. With the second fingerprint, we make a close observation of the tortuous matrix pore network by means...... of a modified Buckingham (1904) pore connectivity factor (X*). The third fingerprint of the fracture network involves the average angle of diffusion α (Moldrup et al. 2010), a parameter which characterizes the average angle at which the fractures are penetrating the sample....

Does the emergency surgery score accurately predict outcomes in emergent laparotomies?

Science.gov (United States)

Peponis, Thomas; Bohnen, Jordan D; Sangji, Naveen F; Nandan, Anirudh R; Han, Kelsey; Lee, Jarone; Yeh, D Dante; de Moya, Marc A; Velmahos, George C; Chang, David C; Kaafarani, Haytham M A

2017-08-01

The emergency surgery score is a mortality-risk calculator for emergency general operation patients. We sought to examine whether the emergency surgery score predicts 30-day morbidity and mortality in a high-risk group of patients undergoing emergent laparotomy. Using the 2011-2012 American College of Surgeons National Surgical Quality Improvement Program database, we identified all patients who underwent emergent laparotomy using (1) the American College of Surgeons National Surgical Quality Improvement Program definition of "emergent," and (2) all Current Procedural Terminology codes denoting a laparotomy, excluding aortic aneurysm rupture. Multivariable logistic regression analyses were performed to measure the correlation (c-statistic) between the emergency surgery score and (1) 30-day mortality, and (2) 30-day morbidity after emergent laparotomy. As sensitivity analyses, the correlation between the emergency surgery score and 30-day mortality was also evaluated in prespecified subgroups based on Current Procedural Terminology codes. A total of 26,410 emergent laparotomy patients were included. Thirty-day mortality and morbidity were 10.2% and 43.8%, respectively. The emergency surgery score correlated well with mortality (c-statistic = 0.84); scores of 1, 11, and 22 correlated with mortalities of 0.4%, 39%, and 100%, respectively. Similarly, the emergency surgery score correlated well with morbidity (c-statistic = 0.74); scores of 0, 7, and 11 correlated with complication rates of 13%, 58%, and 79%, respectively. The morbidity rates plateaued for scores higher than 11. Sensitivity analyses demonstrated that the emergency surgery score effectively predicts mortality in patients undergoing emergent (1) splenic, (2) gastroduodenal, (3) intestinal, (4) hepatobiliary, or (5) incarcerated ventral hernia operation. The emergency surgery score accurately predicts outcomes in all types of emergent laparotomy patients and may prove valuable as a bedside decision

Industrial application of limestone deposits of kohat, NWFP: a research towards the sustainability of the deposits

International Nuclear Information System (INIS)

Bilqees, R.; Shah, T.

2007-01-01

Chemical analyses, petrographic studies and physical tests of limestone deposits in the vicinity of kohat along Bannu Road, Hangu Road and Rawalpindi Road were carried out to categorize these reserves, locality-wise, for their specified industrial uses. Limestone of kohat area was found to be generally good for construction purposes. The deposits on the Hangu Road were of good quality with more then 97% CaCO/sub 3/ and suitable for use in chemical, iron and steel industries, for glass making, soda ash manufacture etc. The deposit of Bannu Road with 96.5% CaCO/sub 3/ can be used for sugar refining, paint industry, flue gas desulphurization, animal feed etc. The limestone deposit of Rawalpindi Road is inferior in quality having 95.2% CaCO/sub 3/. It can be utilized in rubber industry, as ceramic whiting, building materials, rock wool etc. (author)

Morphological Changes of Limestone Sorbent Particles during Carbonation/Calcination Looping Cycles in a Thermogravimetric Analyzer (TGA) and Reactivation with Steam

KAUST Repository

Wu, Y.; Blamey, J.; Anthony, E. J.; Fennell, P. S.

2010-01-01

Carbonation and calcination looping cycles were carried out on four limestones in a thermogravimetric analyzer (TGA). The CO2 carrying capacity of a limestone particle decays very quickly in the first 10 cycles, reducing to about 20% of its original

A machine learned classifier that uses gene expression data to accurately predict estrogen receptor status.

Directory of Open Access Journals (Sweden)

Meysam Bastani

Full Text Available BACKGROUND: Selecting the appropriate treatment for breast cancer requires accurately determining the estrogen receptor (ER status of the tumor. However, the standard for determining this status, immunohistochemical analysis of formalin-fixed paraffin embedded samples, suffers from numerous technical and reproducibility issues. Assessment of ER-status based on RNA expression can provide more objective, quantitative and reproducible test results. METHODS: To learn a parsimonious RNA-based classifier of hormone receptor status, we applied a machine learning tool to a training dataset of gene expression microarray data obtained from 176 frozen breast tumors, whose ER-status was determined by applying ASCO-CAP guidelines to standardized immunohistochemical testing of formalin fixed tumor. RESULTS: This produced a three-gene classifier that can predict the ER-status of a novel tumor, with a cross-validation accuracy of 93.17±2.44%. When applied to an independent validation set and to four other public databases, some on different platforms, this classifier obtained over 90% accuracy in each. In addition, we found that this prediction rule separated the patients' recurrence-free survival curves with a hazard ratio lower than the one based on the IHC analysis of ER-status. CONCLUSIONS: Our efficient and parsimonious classifier lends itself to high throughput, highly accurate and low-cost RNA-based assessments of ER-status, suitable for routine high-throughput clinical use. This analytic method provides a proof-of-principle that may be applicable to developing effective RNA-based tests for other biomarkers and conditions.

In vitro transcription accurately predicts lac repressor phenotype in vivo in Escherichia coli

Directory of Open Access Journals (Sweden)

Matthew Almond Sochor

2014-07-01

Full Text Available A multitude of studies have looked at the in vivo and in vitro behavior of the lac repressor binding to DNA and effector molecules in order to study transcriptional repression, however these studies are not always reconcilable. Here we use in vitro transcription to directly mimic the in vivo system in order to build a self consistent set of experiments to directly compare in vivo and in vitro genetic repression. A thermodynamic model of the lac repressor binding to operator DNA and effector is used to link DNA occupancy to either normalized in vitro mRNA product or normalized in vivo fluorescence of a regulated gene, YFP. An accurate measurement of repressor, DNA and effector concentrations were made both in vivo and in vitro allowing for direct modeling of the entire thermodynamic equilibrium. In vivo repression profiles are accurately predicted from the given in vitro parameters when molecular crowding is considered. Interestingly, our measured repressor–operator DNA affinity differs significantly from previous in vitro measurements. The literature values are unable to replicate in vivo binding data. We therefore conclude that the repressor-DNA affinity is much weaker than previously thought. This finding would suggest that in vitro techniques that are specifically designed to mimic the in vivo process may be necessary to replicate the native system.

Improving DMS 9210 requirements for limestone rock asphalt : year one interim report.

Science.gov (United States)

2013-05-01

Limestone Rock Asphalt (LRA) mixtures have been produced and placed for several decades using specification requirements currently listed under DMS 9210. Several Districts have had placement issues and premature failures at the beginning of 2010. The...

A Weibull statistics-based lignocellulose saccharification model and a built-in parameter accurately predict lignocellulose hydrolysis performance.

Science.gov (United States)

Wang, Mingyu; Han, Lijuan; Liu, Shasha; Zhao, Xuebing; Yang, Jinghua; Loh, Soh Kheang; Sun, Xiaomin; Zhang, Chenxi; Fang, Xu

2015-09-01

Renewable energy from lignocellulosic biomass has been deemed an alternative to depleting fossil fuels. In order to improve this technology, we aim to develop robust mathematical models for the enzymatic lignocellulose degradation process. By analyzing 96 groups of previously published and newly obtained lignocellulose saccharification results and fitting them to Weibull distribution, we discovered Weibull statistics can accurately predict lignocellulose saccharification data, regardless of the type of substrates, enzymes and saccharification conditions. A mathematical model for enzymatic lignocellulose degradation was subsequently constructed based on Weibull statistics. Further analysis of the mathematical structure of the model and experimental saccharification data showed the significance of the two parameters in this model. In particular, the λ value, defined the characteristic time, represents the overall performance of the saccharification system. This suggestion was further supported by statistical analysis of experimental saccharification data and analysis of the glucose production levels when λ and n values change. In conclusion, the constructed Weibull statistics-based model can accurately predict lignocellulose hydrolysis behavior and we can use the λ parameter to assess the overall performance of enzymatic lignocellulose degradation. Advantages and potential applications of the model and the λ value in saccharification performance assessment were discussed. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Downflow limestone beds for treatment of net-acidic, oxic, iron-laden drainage from a flooded Anthracite Mine, Pennsylvania, USA: 1. Field evaluation

Science.gov (United States)

Cravotta, C.A.; Ward, S.J.

2008-01-01

Passive-treatment systems that route acidic mine drainage (AMD) through crushed limestone and/or organic-rich substrates have been used to remove the acidity and metals from various AMD sources, with a wide range of effects. This study evaluates treatment of net-acidic, oxic, iron-laden AMD with limestone alone, and with organic-rich compost layered with the limestone. In the fall of 2003, a treatment system consisting of two parallel, 500-m2 downflow cells followed by a 400-m2 aerobic settling pond and wetland was installed to neutralize the AMD from the Bell Mine, a large source of AMD and baseflow to the Schuylkill River in the Southern Anthracite Coalfield, in east-central Pennsylvania. Each downflow cell consisted of a lower substrate layer of 1,090 metric tons (t) of dolomitic limestone (60 wt% CaCO3) and an upper layer of 300 t of calcitic limestone (95 wt% CaCO3); one of the downflow cells also included a 0.3 m thick layer of mushroom compost over the limestone. AMD with pH of 3.5-4.3, dissolved oxygen of 6.6-9.9 mg/L, iron of 1.9-5.4 mg/L, and aluminum of 0.8-1.9 mg/L flooded each cell to a depth 0.65 m above the treatment substrates, percolated through the substrates to underlying, perforated outflow pipes, and then flowed through the aerobic pond and wetland before discharging to the Schuylkill River. Data on the flow rates and chemistry of the effluent for the treatment system indicated substantial neutralization by the calcitic limestone but only marginal effects from the dolomitic limestone or compost. Because of its higher transmissivity, the treatment cell containing only limestone neutralized greater quantities of acidity than the cell containing compost and limestone. On average, the treatment system removed 62% of the influent acidity, 47% of the dissolved iron, 34% of the dissolved aluminum, and 8% of the dissolved manganese. Prior to treatment of the Bell Discharge, the Schuylkill River immediately below its confluence with the discharge had p

Treatment of iron(II)-rich acid mine water with limestone and oxygen.

Science.gov (United States)

Mohajane, G B; Maree, J P; Panichev, N

2014-01-01

The main components of acid mine water are free acid, sulphate, and Fe²⁺. Limestone is the most cost-effective alkali that can be used for neutralization. The purpose of this investigation was to identify conditions where Fe²⁺ is removed with limestone and simultaneously oxidized with oxygen to Fe³⁺, in a polyvinyl chloride pipe under pressure. Gypsum scaling is prevented by passing rubber balls through the pipe of the so-called Oxygen-Pipe-Neutralization (OPeN) process pilot plant. Two synthetic waters were treated: (A) acid mine water containing 123 mg L⁻¹ Fe²⁺ representing gold mine water, and (B) acid mine water containing 6,032 mg L⁻¹ Fe²⁺ representing coal mine water. Batch studies were carried out in a pipe reactor and showed that the rate of Fe²⁺ oxidation depended on the Fe²⁺ concentration, oxygen pressure, amount of recycled sludge, limestone dosage and the mixing rate. Continuous studies in an OPeN process pilot plant resulted in 100% removal of total acidity from synthetic coal mine water and a 98% removal from synthetic gold mine water. Fe²⁺ was removed completely as precipitated Fe(OH)₃ from both synthetic coal and gold mine water at around pH 7 at 200 and 100 kPa oxygen pressure, respectively.

Effects of different limestone particle sizes in the diet of broiler breeders post molting on their performance, egg quality, incubation results, and pre-starter performance of their progeny.

Science.gov (United States)

Bueno, I J M; Surek, D; Rocha, C; Schramm, V G; Muramatsu, K; Dahlke, F; Maiorka, A

2016-04-01

An experiment was conducted to test the hypothesis that a coarse limestone diet improves productivity, reproductive performance and the calcium utilization of molted broiler breeders. In total, 640 broiler breeder females, 73-week-old and sixty-four 27-week-old cockerels, Cobb 500, were evaluated during 10 weeks, according to a randomized block design composed of 4 treatments with 8 replicates each. Treatments consisted of diets with the inclusion of 100% fine limestone-fine PS (0.2 mm GMD-geometric mean diameter); PS1: 30% fine limestone+70% limestone with 1.0 mm GMD; PS2: 30% fine limestone+70% limestone with 2.0 mm GMD; and PS3: 30% fine limestone+70% limestone with 3.0 mm GMD. Calcium retention in the gizzard of the breeders, bone characteristics, and breeder performance, egg characteristics, eggshell quality, incubation performance, chick quality and yield, chick pre-starter live performance, and chick bone characteristics were determined. There was no significant difference (P>0.05) in the rate of lay, percentage of non-settable eggs, egg weight, egg shape index, egg specific gravity, eggshell weight, thickness, and percentage hatchability and egg weight loss of broiler breeders fed with diets with different limestone particle sizes. The chick quality and yield, chick pre-starter live performance, and chick bone characteristics were not affected (P>0.05) by any of the limestone particle sizes. It was concluded that live and reproductive performance parameters of broiler breeders post molting is not affected by limestone particle size in the feed. © 2016 Poultry Science Association Inc.

Physico-chemical investigations of limestones from different localities in the Republic of Macedonia

International Nuclear Information System (INIS)

Arabadzhiev, Dimitrios M.; Stefov, Viktor; Boev, Blazho

2001-01-01

Physico-chemical investigations were carried out for limestone samples at different localities in the Republic of Macedonia: mine for nonmetals O graiden , Strumica (sample-granulation below: 4, 10, 20, 32, 40, 63 and 90 gm), A.D. M ikrogranulat , Gostivar, mine 'Banjani' - Skopje, mine 'Toplica' near Demir Hisar and from the separation of GP Mavrovo, Skopje, located near Pletvar. Investigation of samples from the previously mentioned localities were carried out using different methods: volumetry, gravimetry, UV-VIS and infrared spectroscopy, as well as atomic absorption and X-ray fluorescence spectrometry, X-ray diffraction and flame photometry. The obtained results lead to the conclusion that all granulometric classes of the limestone samples from 'Ograzhden', Strumica, are of the best quality. (Original)

Successful experience with limestone and other sorbents for combustion of biomass in fluid bed power boilers

Energy Technology Data Exchange (ETDEWEB)

Coe, D.R. [LG& E Power Systems, Inc., Irvine, CA (United States)

1993-12-31

This paper presents the theoretical and practical advantages of utilizing limestone and other sorbents during the combustion of various biomass fuels for the reduction of corrosion and erosion of boiler fireside tubing and refractory. Successful experiences using a small amount of limestone, dolomite, kaolin, or custom blends of aluminum and magnesium compounds in fluid bed boilers fired with biomass fuels will be discussed. Electric power boiler firing experience includes bubbling bed boilers as well as circulating fluid bed boilers in commercial service on biomass fuels. Forest sources of biomass fuels fired include wood chips, brush chips, sawmill waste wood, bark, and hog fuel. Agricultural sources of biomass fuels fired include grape vine prunings, bean straw, almond tree chips, walnut tree chips, and a variety of other agricultural waste fuels. Additionally, some urban sources of wood fuels have been commercially burned with the addition of limestone. Data presented includes qualitative and quantitative analyses of fuel, sorbent, and ash.

TL glow curve analysis of UV, beta and gamma induced limestone collected from Amarnath holy cave

Directory of Open Access Journals (Sweden)

Vikas Dubey

2015-01-01

Full Text Available The paper reports themoluminescence glow curve analysis of UV (ultraviolet, β (beta and γ (gamma induced limestone collected from Amarnath holy cave. The collected natural sample was characterized by X-ray diffraction (XRD technique and crystallite size calculated by Scherer's formula. Surface morphology and particle size was calculated by transmission electron microscopy (TEM study. Effect of annealing temperature on collected lime stone examined by TL glow curve study. The limestone was irradiated by UV radiation (254 nm source and the TL glow curve recorded for different UV exposure time. For beta irradiation Sr90 source was used and is shows intense peak at 256 °C with a shoulder peak at higher temperature range. For gamma radiation Co60 source and TL glow curve recorded for different doses of gamma. The kinetic parameters calculation was performed for different glow curve by computerized glow curve deconvolution (CGCD technique. The chemical composition of natural limestone was analyzed by energy dispersive X-ray spectroscopy (EDXS.

Comparison of water absorption methods: testing the water absorption of recently quarried and weathered porous limestone on site and under laboratory conditions

Science.gov (United States)

Rozgonyi-Boissinot, Nikoletta; Agárdi, Tamás; Karolina Cebula, Ágnes; Török, Ákos

2017-04-01

The water absorption of weathering sensitive stones is a critical parameter that influences durability. The current paper compares different methods of water absorption tests by using on site and laboratory tests. The aims of the tests were to assess the water absorption of un-weathered quarry stones and various weathering forms occurring on porous limestone monuments. For the tests a Miocene porous limestone was used that occurs in Central and Western Hungary and especially near and in Budapest. Besides the Hungarian occurrences the same or very similar porous limestones are found in Austria, Slovakia and in the Czech Republic. Several quarries were operating in these countries. Due to the high workability the stone have been intensively used as construction material from the Roman period onward. The most prominent monuments made of this stone were built in Vienna and in Budapest during the 18th -19th century and in the early 20th century. The high porosity and the micro-fabric of the stone make it prone to frost- and salt weathering. Three different limestone types were tested representing coarse-, medium- and fine grained lithologies. The test methods included Rilem tube (Karsten tube) tests and capillary water absorption tests. The latter methodology has been described in detail in EN 1925:2000. The test results of on-site tests of weathered porous limestone clearly show that the water absorption of dissolved limestone surfaces and crumbling or micro-cracked limestone is similar. The water absorption curves have similar inclinations marking high amount of absorbed water. To the contrary, the white weathering crusts covered stone blocks and black crusts have significantly lower water absorptions and many of these crusts are considered as very tight almost impermeable surfaces. Capillary water absorption tests in the laboratory allowed the determination of maximum water absorption of quarried porous limestone. Specimens were placed in 3 mm of water column and the

Wet separation processes as method to separate limestone and oil shale

Science.gov (United States)

Nurme, Martin; Karu, Veiko

2015-04-01

Biggest oil shale industry is located in Estonia. Oil shale usage is mainly for electricity generation, shale oil generation and cement production. All these processes need certain quality oil shale. Oil shale seam have interlayer limestone layers. To use oil shale in production, it is needed to separate oil shale and limestone. A key challenge is find separation process when we can get the best quality for all product types. In oil shale separation typically has been used heavy media separation process. There are tested also different types of separation processes before: wet separation, pneumatic separation. Now oil shale industry moves more to oil production and this needs innovation methods for separation to ensure fuel quality and the changes in quality. The pilot unit test with Allmineral ALLJIG have pointed out that the suitable new innovation way for oil shale separation can be wet separation with gravity, where material by pulsating water forming layers of grains according to their density and subsequently separates the heavy material (limestone) from the stratified material (oil shale)bed. Main aim of this research is to find the suitable separation process for oil shale, that the products have highest quality. The expected results can be used also for developing separation processes for phosphorite rock or all others, where traditional separation processes doesn't work property. This research is part of the study Sustainable and environmentally acceptable Oil shale mining No. 3.2.0501.11-0025 http://mi.ttu.ee/etp and the project B36 Extraction and processing of rock with selective methods - http://mi.ttu.ee/separation; http://mi.ttu.ee/miningwaste/

Liquification and soft-sediment deformation in a limestone megabreccia: The Ayabacas giant collapse, Cretaceous, southern Peru

Science.gov (United States)

Callot, Pierre; Odonne, Francis; Sempere, Thierry

2008-12-01

In the back-arc basin of southern Peru, the bulk of the mid-Cretaceous carbonate platform collapsed near the Turonian-Coniacian boundary (~ 90-89 Ma), due to slope creation and resulting oversteepening. The resulting mass-wasting deposits, namely the Ayabacas Formation, consist of a megabreccia which is organised from NE to SW in relation with two major fault systems. Facies of sediment reworking (such as brecciation, liquification, sedimentary dykes and soft-sediment deformation) are described and four types of resedimentation facies are define. In the northeastern part of the study area, deposits mainly consist of a mixture of very heterometric clasts and blocks (millimetric to kilometric in size), mainly carbonate but also sandy-marly in nature, floating in sandy-marly matrix that exhibits features of liquification (sedimentary dykes and flows) and plastic deformation. Here, resedimentation facies are characterized by deformations and a brecciated facies at each observation scale (from aerial photographs to thin sections) and are therefore defined as fractal or multi-scale breccias. Some clasts and large amounts of the matrix were derived from the underlying clay-rich sandstones of the Murco Formation. These materials were prone to liquification and plastic deformation, allowing them to act as a sliding sole that facilitated the slides and the downslope movement of large limestone rafts. In the southwestern part of the study area, only limestone breccias are observed, in alternation with well-stratified levels. The sliding sole of plastically deformable siliciclastic sediments that previously acted as a lubricating layer was not present here, as materials were more deeply buried. Variations in the degree of sediment lithification from northeast to southwest are inferred to have existed before the collapse and also within the sedimentary succession in the northeastern part. In particular, limestones were well-cemented at the base of the carbonate succession and

Lateral capacity of rock sockets in limestone under cyclic and repeated loading.

Science.gov (United States)

2010-08-01

This report contains the results from full scale lateral load testing of two short rock socketed shafts in : limestone, and the development of recommendations for p-y analysis using those results. Two short shafts 42 : inches in diameter were constru...

Accurate prediction of the dew points of acidic combustion gases by using an artificial neural network model

International Nuclear Information System (INIS)

ZareNezhad, Bahman; Aminian, Ali

2011-01-01

This paper presents a new approach based on using an artificial neural network (ANN) model for predicting the acid dew points of the combustion gases in process and power plants. The most important acidic combustion gases namely, SO 3 , SO 2 , NO 2 , HCl and HBr are considered in this investigation. Proposed Network is trained using the Levenberg-Marquardt back propagation algorithm and the hyperbolic tangent sigmoid activation function is applied to calculate the output values of the neurons of the hidden layer. According to the network's training, validation and testing results, a three layer neural network with nine neurons in the hidden layer is selected as the best architecture for accurate prediction of the acidic combustion gases dew points over wide ranges of acid and moisture concentrations. The proposed neural network model can have significant application in predicting the condensation temperatures of different acid gases to mitigate the corrosion problems in stacks, pollution control devices and energy recovery systems.

Flora of Chihuahuan desertscrub on limestone in northeastern Sonora, Mexico

Science.gov (United States)

Thomas R. Van Devender; Ana Lilia Reina-Guerrero; J. Jesus. Sanchez-Escalante

2013-01-01

Transects were done in desertscrub on limestone to characterize the flora of the westernmost Chihuahuan Desert. Most of the sites (15) were in the Municipios of Agua Prieta and Naco in northeastern Sonora, with single sites near Ascensión, northwestern Chihuahua and east of Douglas in southeastern Arizona. A total of 236 taxa were recorded on transects. Dicot perennial...

Geochemical and mineralogical characteristics of percolates and its evaporates from Technosols before and after limestone filler stabilisation.

Science.gov (United States)

Pérez-Sirvent, Carmen; Martinez-Sanchez, Maria Jose; Garcia-Lorenzo, Maria Luz; Hernandez-Cordoba, Manuel

2017-04-01

The chemistry of waters is recognized as a relevant monitoring tool when assessing the adverse effects of acid mine drainage. The weathering of sulphide minerals produces a great variety of efflorescences of soluble sulphate salts. These minerals play an important role for environmental pollution, since they can be either a sink or a source for acidity and trace elements. This communication deals with the leachability of potentially toxic elements (PTE) eluting from technosols formed from soils affected by mining activities and limestone filler. A total of three contaminated soils affected by opencast mining were selected and mixed with limestone filler at three percentages: 10 %, 20 % and 30 %, providing nine stabilised samples. These samples were stored in containers and moistened simulating rainfall. The percolates obtained were collected, and the PTEs content (As, Cd, Cu, Fe, Pb and Zn) was determined. Evaporation-precipitation experiments were carried out in these waters, and the mineralogical composition of efflorescences was evaluated. The study area is heavily polluted as a result of historical mining and processing activities, producing large amount of wastes, characterised by high trace elements content and acidic pH. The results obtained for the percolates after the rain episode showed that, before the stabilization approach, waters had an acidic pH, high electrical conductivity and high PTEs content. When these soils were mixed with 10, 20 and 30 % of limestone filler, the pH was neutral and the soluble trace element content strongly decreased, being under the detection limit when limestone percentage was 20 % and 30 %. The mineralogical composition of efflorescences before the stabilisation approach showed that predominant minerals were copiapite, followed by gypsum and bilinite. Other soluble sulphates were determined in lower percentage, such as hexahydrite, halotriquite or pickeringite. After the mixing with 10 % of limestone filler, the evaporates

Effect of limestone addition on chlorine compound emissions in grate and fluidized-bed combustion of recovered fuels

International Nuclear Information System (INIS)

Vesterinen, R.; Ruuskanen, J.

2000-01-01

The aim was to verify the positive results of laboratory experiments concerning the reducing effect of limestone addition on emissions of organic chlorine compounds and acidifying compounds (HCl, HF, SO 2 ) in grate and fluidized-bed combustion of recovered fuels in commercial boilers. The final aim is to develop a cheap and practical way of reducing emissions of organic chlorine compounds in co-combustion of recovered fuels. Pellets produced from the mixture of recovered fuel and limestone is a product ready for use in plants without any need of additional employees or equipment for limestone feed. Pellets produced by Ewapower Oy are used as recovered fuel and Gotland limestone of Partek Nordkalk Oyj Abp as limestone. Ewapower Oy produces pellets by feeding a certain proportion of limestone among recovered fuel at the production stage. Experiments are carried out in one grate-combustion plant and in one or two fluidized-bed plants. The first experiments were carried out in a 3 MWth BioGrate boiler at the new heating station of Pielavesi municipality in autumn 1999. The flue gases are cleaned with a cyclone (FinCleaner). The main fuel was a mixture of bark and sawdust (3:1) from a sawmill. Ewapower pellets with an addition of Gotland limestone were used as recovered fuel. The experiments were carried out at about 2 MW boiler output. Temperatures of the furnace and flue gas, pressure and fuel gas composition were measured continuously. For determining the composition of gas, O 2 , CO, CO 2 , hydrocarbons and N 2 O(FTIR), NO x and SO 2 were measured continuously. HCl, heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDF), polyaromatic hydrocarbons (PAH), chlorobenzenes, chlorophenols and PCB were measured as one-shot determinations. Fuel and ash samples were also collected during the experiments. The organic compounds were analyzed by the Department of Environmental Science of the University of Kuopio, which is

Predicting Falls in People with Multiple Sclerosis: Fall History Is as Accurate as More Complex Measures

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Michelle H. Cameron

2013-01-01

Full Text Available Background. Many people with MS fall, but the best method for identifying those at increased fall risk is not known. Objective. To compare how accurately fall history, questionnaires, and physical tests predict future falls and injurious falls in people with MS. Methods. 52 people with MS were asked if they had fallen in the past 2 months and the past year. Subjects were also assessed with the Activities-specific Balance Confidence, Falls Efficacy Scale-International, and Multiple Sclerosis Walking Scale-12 questionnaires, the Expanded Disability Status Scale, Timed 25-Foot Walk, and computerized dynamic posturography and recorded their falls daily for the following 6 months with calendars. The ability of baseline assessments to predict future falls was compared using receiver operator curves and logistic regression. Results. All tests individually provided similar fall prediction (area under the curve (AUC 0.60–0.75. A fall in the past year was the best predictor of falls (AUC 0.75, sensitivity 0.89, specificity 0.56 or injurious falls (AUC 0.69, sensitivity 0.96, specificity 0.41 in the following 6 months. Conclusion. Simply asking people with MS if they have fallen in the past year predicts future falls and injurious falls as well as more complex, expensive, or time-consuming approaches.

Geologic framework and hydrogeologic features of the Glen Rose Limestone, Camp Bullis Training Site, Bexar County, Texas

Science.gov (United States)

Clark, Allan K.

2003-01-01

The Glen Rose Limestone crops out over most of the Camp Bullis Training Site in northern Bexar County, Texas, where it consists of upper and lower members and composes the upper zone and the upper part of the middle zone of the Trinity aquifer. Uncharacteristically permeable in northern Bexar County, the Glen Rose Limestone can provide avenues for recharge to and potential contamination of the downgradient Edwards aquifer, which occupies the southeastern corner of Camp Bullis.The upper member of the Glen Rose Limestone characteristically is thin-bedded and composed mostly of soft limestone and marl, and the lower Glen Rose typically is composed mostly of relatively massive, fossiliferous limestone. The upper member, about 410 to 450 feet thick at Camp Bullis, was divided in this study into five hydrogeologic subdivisions, A through E (youngest to oldest).The approximately 120-foot-thick Interval A has an abundance of caves, which is indicative of its generally well developed fracture, channel, and cavern porosity that in places provides appreciable permeability. The 120- to 150-foot-thick Interval B is similar to Interval A but with less cave development and considerably less permeability. The 10- to 20-foot-thick Interval C, a layer of partly to mostly dissolved soluble carbonate minerals, is characterized by breccia porosity, boxwork permeability, and collapse structures that typically divert ground water laterally to discharge at land surface. The 135- to 180-foot-thick Interval D generally has low porosity and little permeability with some local exceptions, most notably the caprinid biostrome just below the top of the interval, which appears to be permeable by virtue of excellent moldic, vug, fracture, and cavern porosity. The 10- to 20-foot-thick Interval E, a layer of partly to mostly dissolved evaporites similar to Interval C, has similar hydrogeologic properties and a tendency to divert ground water laterally.

Treatment Of Metal-Mine Effluents By Limestone Neutralization And Calcite Co-Precipitation

Science.gov (United States)

The U.S. Geological Survey - Leetown Science Center and the Colorado School of Mines have developed a remediation process for the treatment of metals in circumneutral mining influenced waters. The process involves treatment with a pulsed limestone bed (PLB) system, followed by c...

Arbuscular mycorrhizal fungi in a semi-arid, limestone mining-impacted area of Brazil

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Thaís Teixeira-Rios

2013-12-01

Full Text Available The main goal of this study was to determine the diversity and activity of arbuscular mycorrhizal fungi (AMF in an area degraded by limestone mining within the semi-arid region of Brazil known as the caatinga (shrublands. Near a limestone quarry, we selected two areas of caatinga (preserved and degraded for study. The number of glomerospores did not differ significantly between the two areas. There was a trend toward the most probable number of infective propagules being higher in the degraded area. Twenty AMF taxa were identified in the two sampled areas, species richness, diversity and evenness being higher in the preserved area. Two species of Racocetra represent new records for the semi-arid region of Brazil. Glomerospore production and AMF species richness were unaffected by mining activity in the study area.

Investigations of a Cretaceous limestone with spectral induced polarization and scanning electron microscopy

DEFF Research Database (Denmark)

Johansson, Sara; Sparrembom, Charlotte; Fiandaca, Gianluca

2017-01-01

limestone was carried out in the Kristianstad basin, Sweden. The time domain IP data was processed with a recently developed method in order to suppress noise from the challenging urban setting in the survey area. The processing also enabled extraction of early decay times resulting in broader spectra...... in early time ranges for bedrock characterization. The inverted sections showed variations within the limestone that could be caused by variations in texture and composition. Samples from a deep drilling in the Kristianstad basin were investigated with scanning electron microscopy and energy dispersive X......Characterization of varying bedrock properties is a common need in various contexts, ranging from large infrastructure pre-investigations to environmental protection. A direct current resistivity and time domain induced polarization (IP) survey aiming to characterize properties of a Cretaceous...

Experimental study of the effect of limestone grading on some mechanical properties of concrete

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Ammari Madiha Z. J.

2017-01-01

Full Text Available This study reports the experimental work undertaken to investigate the optimum grading of limestone to be used in concrete mixes. 36 concrete cubes were prepared for testing. Four different Fineness Moduli and grading were tested 2.4, 2.6, 2.92 and 3. For all tests, the cubes were left in curing until testing at the age of 3, 7 and 28 days respectively. Samples were loaded to failure and the average compressive strength was used for comparison purposes. Flow table test has been performed on the fresh concrete directly after mixing to measure workability and the average of the maximum concrete spread parallel to the two edges of the table was recorded. Results revealed that the optimum Fineness Modulus for the limestone to be used as fine aggregate in the concrete mix to get maximum compressive strength is 2.78. The flow table tests revealed an increment in the workability of fresh concrete with higher Fineness Modulus of limestone used in the concrete mix as fine aggregate. The workability of the optimum Fineness Modulus, 2.78, was found to be 412 mm which is a mix with considerable workability. An ideal grading has been recommended in this research study and checked to match the ASTM grading requirements for fine aggregate.

Compressive strength evolution of thermally-stressed Saint Maximin limestone.

Science.gov (United States)

Farquharson, J.; Griffiths, L.; Baud, P.; Wadsworth, F. B.; Heap, M. J.

2017-12-01

The Saint Maximin quarry (Oise, France) opened in the early 1600s, and its limestone has been used extensively as masonry stone, particularly during the classical era of Parisian architecture from the 17th century onwards. Its widespread use has been due to a combination of its regional availability, its high workability, and its aesthetic appeal. Notable buildings completed using this material include sections of the Place de la Concorde and the Louvre in Paris. More recently, however, it has seen increasing use in the construction of large private residences throughout the United States as well as extensions to private institutions such as Stanford University. For any large building, fire hazard can be a substantial concern, especially in tectonically active areas where catastrophic fires may arise following large-magnitude earthquakes. Typically, house fires burn at temperatures of around 600 °C ( 1000 F). Given the ubiquity of this geomaterial as a building stone, it is important to ascertain the influence of heating on the strength of Saint Maximin limestone (SML), and in turn the structural stability of the buildings it is used in. We performed a series of compressive tests and permeability measurements on samples of SML to determine its strength evolution in response to heating to incrementally higher temperatures. We observe that the uniaxial compressive strength of SML decreases from >12 MPa at room temperature to 400 °C). We anticipate that this substantial weakening is in part a result of thermal microcracking, whereby changes in temperature induce thermal stresses due to a mismatch in thermal expansion between the constituent grains. This mechanism is compounded by the volumetric increase of quartz through its alpha - beta transition at 573 °C, and by the thermal decomposition of calcite. To track the formation of thermal microcracks, we monitor acoustic emissions, a common proxy for microcracking, during the heating of an SML sample. The

OPTIMALIZATION OF BLASTING IN »LAKOVIĆI« LIMESTONE QUARRY

OpenAIRE

Branko Božić; Karlo Braun

1992-01-01

The optimalization of exploitation in »Lakovići« limestone quarry is described. Based on determined discontinuities in the rock mass and their densities, the best possible working site have been located in order to obtain the best possible sizes of blasted rocks and work slope stability. Optimal lowest resistance line size for the quarry has been counted and proved experimentally. New blasting parameters have resulted in considerable saving of drilling and explosive (the paper is published in...

The nature of Ordovician limestone-marl alternations in the Oslo-Asker District (Norway): witnesses of primary glacio-eustasy or diagenetic rhythms?

Science.gov (United States)

Amberg, Chloé E. A.; Collart, Tim; Salenbien, Wout; Egger, Lisa M.; Munnecke, Axel; Nielsen, Arne T.; Monnet, Claude; Hammer, Øyvind; Vandenbroucke, Thijs R. A.

2016-01-01

Ordovician limestone-marl alternations in the Oslo-Asker District have been interpreted as signaling glacio-eustatic lowstands, which would support a prolonged “Early Palaeozoic Icehouse”. However, these rhythmites could alternatively reflect differential diagenesis, without sedimentary trigger. Here, we test both hypotheses through one Darriwilian and three Katian sections. Our methodology consists of a bed-by-bed analysis of palynological (chitinozoan) and geochemical (XRF) data, to evaluate whether the limestone/marl couplets reflect an original cyclic signal. The results reveal similar palynomorph assemblages in limestones and marls. Exceptions, which could be interpreted as reflecting palaeoclimatological fluctuations, exist at the species level: Ancyrochitina bornholmensis seems to be more abundant in the marl samples from the lower Frognerkilen Formation on Nakkholmen Island. However, these rare cases where chitinozoans differ between limestone/marl facies are deemed insufficient for the identification of original cyclicity. The geochemical data show a near-perfect correlation between insoluble elements in the limestone and the marls, which indicates a similar composition of the potential precursor sediment, also in the Frognerkilen Formation. This is consistent with the palynological data. Although an original cyclic pattern could still be recorded by other, uninvestigated parameters, our palaeontological and geochemical data combined do not support the presence of such a signal.

Hydrobiogeochemical interactions in 'anoxic' limestone drains for neutralization of acidic mine drainage

Science.gov (United States)

Robbins, E.I.; Cravotta, C.A.; Savela, C.E.; Nord, G.L.

1999-01-01

Processes affecting neutralization of acidic coal mine drainage were evaluated within 'anoxic' limestone drains (ALDs). Influents had pH???3.5 and dissolved oxygen treatment step is indicated to promote Al removal before diverting acidic mine water into alkalinity-producing materials. ?? 1998 Elsevier Science Ltd.

Estimating porosity and solid dielectric permittivity in the Miami Limestone using high-frequency ground penetrating radar (GPR) measurements at the laboratory scale

Science.gov (United States)

Mount, Gregory J.; Comas, Xavier

2014-10-01

Subsurface water flow in South Florida is largely controlled by the heterogeneous nature of the karst limestone in the Biscayne aquifer and its upper formation, the Miami Limestone. These heterogeneities are amplified by dissolution structures that induce changes in the aquifer's material and physical properties (i.e., porosity and dielectric permittivity) and create preferential flow paths. Understanding such patterns are critical for the development of realistic groundwater flow models, particularly in the Everglades, where restoration of hydrological conditions is intended. In this work, we used noninvasive ground penetrating radar (GPR) to estimate the spatial variability in porosity and the dielectric permittivity of the solid phase of the limestone at centimeter-scale resolution to evaluate the potential for field-based GPR studies. A laboratory setup that included high-frequency GPR measurements under completely unsaturated and saturated conditions was used to estimate changes in electromagnetic wave velocity through Miami Limestone samples. The Complex Refractive Index Model was used to derive estimates of porosity and dielectric permittivity of the solid phase of the limestone. Porosity estimates of the samples ranged between 45.2 and 66.0% and showed good correspondence with estimates of porosity using analytical and digital image techniques. Solid dielectric permittivity values ranged between 7.0 and 13.0. This study shows the ability of GPR to image the spatial variability of porosity and dielectric permittivity in the Miami Limestone and shows potential for expanding these results to larger scales and other karst aquifers.

Limestone amendments and the establishment of legumes on pyritic colliery spoil

Energy Technology Data Exchange (ETDEWEB)

Jefferies, R A

1981-11-01

This paper examines the effect of high liming, using two commercially available limestone grades of different particle size distributions, on the establishment of six contrasting legume species, in order to determine whether other legume species are more tolerant of the conditions imposed by high liming, and whether the effect can be avoided. 13 refs.

Elemental and mineralogical imaging of a weathered limestone rock by double-pulse micro-Laser-Induced Breakdown Spectroscopy

Science.gov (United States)

Senesi, Giorgio S.; Campanella, Beatrice; Grifoni, Emanuela; Legnaioli, Stefano; Lorenzetti, Giulia; Pagnotta, Stefano; Poggialini, Francesco; Palleschi, Vincenzo; De Pascale, Olga

2018-05-01

The present work aims to evaluate the alteration conditions of historical limestone rocks exposed to urban environment using the Laser-Induced Breakdown Spectroscopy (LIBS) technique. The approach proposed is based on the microscale three dimensional (3D) compositional imaging of the sample through double-pulse micro-Laser-Induced Breakdown Spectroscopy (DP-μLIBS) in conjunction with optical microscopy. DP-μLIBS allows to perform a quick and detailed in-depth analysis of the composition of the weathered artifact by creating a 'virtual thin section' (VTS) of the sample which can estimate the extent of the alteration processes occurred at the limestone surface. The DP-μLIBS analysis of these thin sections showed a reduction with depth of the elements (mainly Fe, Si and Na) originating from atmospheric dust, particulate deposition and the surrounding environment (due to the proximity of the sea), whereas, the LIBS signal of Ca increased in intensity from the black crust to the limestone underneath.

Systematic ichnology of microborings from the Cenozoic White Limestone Group, Jamaica, West Indies

NARCIS (Netherlands)

Blissett, D.J.; Pickerill, R.K.

2007-01-01

The Middle Eocene to Middle Miocene White Limestone Group of Jamaica contains a common and diverse, poorly to well-preserved microboring ichnofauna, namely Centrichnus eccentricus Bromley & Martinell, Curvichnus pediformis isp. nov., Dendrorete balani Tavernier, Campbell & Golubic, Dipatulichnus

Influence of limestone fillers on combustion characteristics of asphalt mortar for pavements

DEFF Research Database (Denmark)

Ke, Wu; Kai, Zhu; Wu, Hao

2014-01-01

Asphalt materials will be ignited and release significant toxic fumes within tunnel fires. Thus, combustion characteristics of asphalt materials used in road tunnel should be studied in order to limit such an adverse effect. In the present work we study the influence of limestone fillers on combu...

Assessing the chemical involvement of limestone powder in sodium carbonate activated slag

NARCIS (Netherlands)

Yuan, B.; Yu, Q.; Brouwers, H.J.H.

2017-01-01

This study aims to investigate the effect of limestone powder (LP) on the reaction of sodium carbonate activated slag. The results show that the incorporated LP up to 30% improves the strength development, especially at advanced curing ages. A slightly accelerated reaction is observed for samples

Stable isotope stratigraphy and larger benthic foraminiferal extinctions in the Melinau Limestone, Sarawak

Science.gov (United States)

Cotton, Laura J.; Pearson, Paul N.; Renema, Willem

2014-01-01

Important long-ranging groups of larger benthic foraminifera (LBF) are known to have become extinct during a period of global cooling and climate disruption at the Eocene-Oligocene transition (EOT) but the precise timing and mechanisms are uncertain. Recent study showed unexpectedly that the LBF extinction in Tanzania occurs very close to the Eocene/Oligocene boundary, as recognised by the extinction of the planktonic foraminiferal Family Hantkeninidae, rather than at the later period of maximum global ice growth and sea-level fall, as previously thought. Here we investigate the same phase of extinction in the Melinau Limestone of Sarawak, on the island of Borneo, Malaysia one of the most complete carbonate successions spanning the Eocene to Lower Miocene. Assemblages of LBF from the Melinau Limestone were studied extensively by Geoffrey Adams during the 1960s-80s, confirming a major extinction during the EOT, but the section lacked independent means of correlation. By analysing rock samples originally studied by Adams and now in the Natural History Museum, London, we provide new bulk stable isotope (δ13C and δ18O) records. This enables us to identify, albeit tentatively, the level of maximum stable isotope excursion and show that the LBF extinction event in the Melinau Limestone occurs below this isotope excursion, supporting the results from Tanzania and indicating that the extinction of LBF close to the Eocene/Oligocene boundary may be a global phenomenon.

Evaluation of modeling approaches to simulate contaminant transport in a fractured limestone aquifer

DEFF Research Database (Denmark)

Mosthaf, Klaus; Fjordbøge, Annika Sidelmann; Broholm, Mette Martina

in fractured limestone aquifers. The model comparison is conducted for a contaminated site in Denmark, where a plume of dissolved PCE has migrated through a fractured limestone aquifer. Field data includes information on spill history, distribution of the contaminant (multilevel sampling), geology...... and hydrogeology. To describe the geology and fracture system, data from borehole logs and cores was combined with an analysis of heterogeneities and fractures from a nearby excavation and pump test data. We present how field data is integrated into the different model concepts. A challenge in the use of field...... and remediation strategies. Each model is compared with field data, considering both model fit and model suitability. Results show a considerable difference between the approaches, and that it is important to select the right one for the actual modeling purpose. The comparison with data showed how much...

OPTIMALIZATION OF BLASTING IN »LAKOVIĆI« LIMESTONE QUARRY

Directory of Open Access Journals (Sweden)

Branko Božić

1992-12-01

Full Text Available The optimalization of exploitation in »Lakovići« limestone quarry is described. Based on determined discontinuities in the rock mass and their densities, the best possible working site have been located in order to obtain the best possible sizes of blasted rocks and work slope stability. Optimal lowest resistance line size for the quarry has been counted and proved experimentally. New blasting parameters have resulted in considerable saving of drilling and explosive (the paper is published in Croatian.

Morphodynamics of Travertine Dam/Waterfall Growth due to the Interaction of Biological Activity, Water Flow and Limestone Emplacement

Science.gov (United States)

Izumi, N.; Parker, G.

2012-12-01

Plitvice Lakes in Croatia are characterized by a step-like train of lakes and waterfalls. The waterfalls are located at the crests of naturally-emplaced dams. The top of each dam grows upward at the rate of a few millimeters per year. It is thought that the upward growth of these dams is caused by the interaction of water flow and biological activity, resulting in the precipitation of dissolved limestone. Dam evolution is initiated by the growth of mosses that favor swift, shallow water. Bacteria that inhabit the roots of the moss excrete solid limestone (travertine) from the water. The limestone fossilizes the moss, and then more moss grows on top of the travertine deposit. In this way, the natural dam can grow over to 10 m high, impounding the water behind it to form a lake. We propose a simple model to explain the formation of natural limestone dams by the interaction between water flow and biologically-mediated travertine deposition. We assume for simplicity that light is the only factor determining the growth of moss, which is then colonized by travertine-emplacing bacteria. We also assume that the water is saturated with dissolved limestone, so that the process is not limited by limestone availability. Photosynthesis, and thus the growth rate of moss are crudely approximated as decreasing linearly with depth. We employ the shallow water equations to describe water flow over the dam. In order to obtain a profile of permanent form for a dam migrating upward and downstream at constant speed, we solve the problem in a moving coordinate system. When water flows over the dam, it is accelerated in the streamwise direction, and the water surface forms a backwater curve. The flow regime changes from Froude-subcritical to Froude-supercritical at a point slightly downstream of the crest of the dam. Farther downstream, the flow attains a threshold velocity beyond which moss is detached. This threshold point defines the downstream end of the active part of the dam. The

Predicting suitable optoelectronic properties of monoclinic VON semiconductor crystals for photovoltaics using accurate first-principles computations

KAUST Repository

Harb, Moussab

2015-01-01

Using accurate first-principles quantum calculations based on DFT (including the perturbation theory DFPT) with the range-separated hybrid HSE06 exchange-correlation functional, we predict essential fundamental properties (such as bandgap, optical absorption coefficient, dielectric constant, charge carrier effective masses and exciton binding energy) of two stable monoclinic vanadium oxynitride (VON) semiconductor crystals for solar energy conversion applications. In addition to the predicted band gaps in the optimal range for making single-junction solar cells, both polymorphs exhibit relatively high absorption efficiencies in the visible range, high dielectric constants, high charge carrier mobilities and much lower exciton binding energies than the thermal energy at room temperature. Moreover, their optical absorption, dielectric and exciton dissociation properties are found to be better than those obtained for semiconductors frequently utilized in photovoltaic devices like Si, CdTe and GaAs. These novel results offer a great opportunity for this stoichiometric VON material to be properly synthesized and considered as a new good candidate for photovoltaic applications.

Predicting suitable optoelectronic properties of monoclinic VON semiconductor crystals for photovoltaics using accurate first-principles computations

KAUST Repository

Harb, Moussab

2015-08-26

Using accurate first-principles quantum calculations based on DFT (including the perturbation theory DFPT) with the range-separated hybrid HSE06 exchange-correlation functional, we predict essential fundamental properties (such as bandgap, optical absorption coefficient, dielectric constant, charge carrier effective masses and exciton binding energy) of two stable monoclinic vanadium oxynitride (VON) semiconductor crystals for solar energy conversion applications. In addition to the predicted band gaps in the optimal range for making single-junction solar cells, both polymorphs exhibit relatively high absorption efficiencies in the visible range, high dielectric constants, high charge carrier mobilities and much lower exciton binding energies than the thermal energy at room temperature. Moreover, their optical absorption, dielectric and exciton dissociation properties are found to be better than those obtained for semiconductors frequently utilized in photovoltaic devices like Si, CdTe and GaAs. These novel results offer a great opportunity for this stoichiometric VON material to be properly synthesized and considered as a new good candidate for photovoltaic applications.

A novel fibrosis index comprising a non-cholesterol sterol accurately predicts HCV-related liver cirrhosis.

Directory of Open Access Journals (Sweden)

Magdalena Ydreborg

Full Text Available Diagnosis of liver cirrhosis is essential in the management of chronic hepatitis C virus (HCV infection. Liver biopsy is invasive and thus entails a risk of complications as well as a potential risk of sampling error. Therefore, non-invasive diagnostic tools are preferential. The aim of the present study was to create a model for accurate prediction of liver cirrhosis based on patient characteristics and biomarkers of liver fibrosis, including a panel of non-cholesterol sterols reflecting cholesterol synthesis and absorption and secretion. We evaluated variables with potential predictive significance for liver fibrosis in 278 patients originally included in a multicenter phase III treatment trial for chronic HCV infection. A stepwise multivariate logistic model selection was performed with liver cirrhosis, defined as Ishak fibrosis stage 5-6, as the outcome variable. A new index, referred to as Nordic Liver Index (NoLI in the paper, was based on the model: Log-odds (predicting cirrhosis = -12.17+ (age × 0.11 + (BMI (kg/m(2 × 0.23 + (D7-lathosterol (μg/100 mg cholesterol×(-0.013 + (Platelet count (x10(9/L × (-0.018 + (Prothrombin-INR × 3.69. The area under the ROC curve (AUROC for prediction of cirrhosis was 0.91 (95% CI 0.86-0.96. The index was validated in a separate cohort of 83 patients and the AUROC for this cohort was similar (0.90; 95% CI: 0.82-0.98. In conclusion, the new index may complement other methods in diagnosing cirrhosis in patients with chronic HCV infection.

T4-related bacteriophage LIMEstone isolates for the control of soft rot on potato caused by 'Dickeya solani'.

Directory of Open Access Journals (Sweden)

Evelien M Adriaenssens

Full Text Available The bacterium 'Dickeya solani', an aggressive biovar 3 variant of Dickeya dianthicola, causes rotting and blackleg in potato. To control this pathogen using bacteriophage therapy, we isolated and characterized two closely related and specific bacteriophages, vB_DsoM_LIMEstone1 and vB_DsoM_LIMEstone2. The LIMEstone phages have a T4-related genome organization and share DNA similarity with Salmonella phage ViI. Microbiological and molecular characterization of the phages deemed them suitable and promising for use in phage therapy. The phages reduced disease incidence and severity on potato tubers in laboratory assays. In addition, in a field trial of potato tubers, when infected with 'Dickeya solani', the experimental phage treatment resulted in a higher yield. These results form the basis for the development of a bacteriophage-based biocontrol of potato plants and tubers as an alternative for the use of antibiotics.

Origin of allochthonous limestone bodies of the miocene Megami formation, Kakegawa district, Shizuoka prefecture. Shizuokaken Kakegawa chiiki no chushinto megamiso ni fukumareru ichisei sekkaigan gantai no kigen

Energy Technology Data Exchange (ETDEWEB)

Nakamori, T; Iryu, Y; Mori, K [Tohoku Univ., Sendai (Japan). Faculty of Science; Sasazawa, K [The Yomiuri Shimbun, Sendai (Japan). Tohoku General Bureau

1991-12-15

The Tertiary limestone bodies represented by Megami Hill and Ogami Hill are distributed in the Kakegawa district in the central portion of Shizuoka Prefecture, these limestone bodies are those originated from coral reefs and are contained in the Megami formation composed of sandstone, mudstone and tuff. However, concerning the limestone bodies of the Megami formation, there are, inter alia, the opinion that they are coral reef sediments on the spot and the opinion that they are foreign rocks, but neither has any firm concrete supporting evidence. In this paper, the sedimentation ages and the sedimentary locations of limestone and sandstone {center dot} mudstone composing the Megami formation were classified and the process, through which limestone was transformed up to its state now observed, was studied. The above study was done by a detailed survey of local rock facies, comparison of age of each rock facies through detection of reference fossils and other measures. A part of the conclusion is shown below: The limestone bodies of the Megami formation is discontinuous with the surrounding sandstone {center dot} mudstone and their strike dip is not harmonious. These limestone bodies are allochthonous rock blocks which collapsed after their sedimentation and mixed with the deep sea sediments (sandstone and mudstone). 37 refs., 4 figs., 4 tabs.

Reliable and accurate point-based prediction of cumulative infiltration using soil readily available characteristics: A comparison between GMDH, ANN, and MLR

Science.gov (United States)

Rahmati, Mehdi

2017-08-01

Developing accurate and reliable pedo-transfer functions (PTFs) to predict soil non-readily available characteristics is one of the most concerned topic in soil science and selecting more appropriate predictors is a crucial factor in PTFs' development. Group method of data handling (GMDH), which finds an approximate relationship between a set of input and output variables, not only provide an explicit procedure to select the most essential PTF input variables, but also results in more accurate and reliable estimates than other mostly applied methodologies. Therefore, the current research was aimed to apply GMDH in comparison with multivariate linear regression (MLR) and artificial neural network (ANN) to develop several PTFs to predict soil cumulative infiltration point-basely at specific time intervals (0.5-45 min) using soil readily available characteristics (RACs). In this regard, soil infiltration curves as well as several soil RACs including soil primary particles (clay (CC), silt (Si), and sand (Sa)), saturated hydraulic conductivity (Ks), bulk (Db) and particle (Dp) densities, organic carbon (OC), wet-aggregate stability (WAS), electrical conductivity (EC), and soil antecedent (θi) and field saturated (θfs) water contents were measured at 134 different points in Lighvan watershed, northwest of Iran. Then, applying GMDH, MLR, and ANN methodologies, several PTFs have been developed to predict cumulative infiltrations using two sets of selected soil RACs including and excluding Ks. According to the test data, results showed that developed PTFs by GMDH and MLR procedures using all soil RACs including Ks resulted in more accurate (with E values of 0.673-0.963) and reliable (with CV values lower than 11 percent) predictions of cumulative infiltrations at different specific time steps. In contrast, ANN procedure had lower accuracy (with E values of 0.356-0.890) and reliability (with CV values up to 50 percent) compared to GMDH and MLR. The results also revealed

Perceived Physician-informed Weight Status Predicts Accurate Weight Self-Perception and Weight Self-Regulation in Low-income, African American Women.

Science.gov (United States)

Harris, Charlie L; Strayhorn, Gregory; Moore, Sandra; Goldman, Brian; Martin, Michelle Y

2016-01-01

Obese African American women under-appraise their body mass index (BMI) classification and report fewer weight loss attempts than women who accurately appraise their weight status. This cross-sectional study examined whether physician-informed weight status could predict weight self-perception and weight self-regulation strategies in obese women. A convenience sample of 118 low-income women completed a survey assessing demographic characteristics, comorbidities, weight self-perception, and weight self-regulation strategies. BMI was calculated during nurse triage. Binary logistic regression models were performed to test hypotheses. The odds of obese accurate appraisers having been informed about their weight status were six times greater than those of under-appraisers. The odds of those using an "approach" self-regulation strategy having been physician-informed were four times greater compared with those using an "avoidance" strategy. Physicians are uniquely positioned to influence accurate weight self-perception and adaptive weight self-regulation strategies in underserved women, reducing their risk for obesity-related morbidity.

Characterization of the spatial distribution of porosity in the eogenetic karst Miami Limestone using ground penetrating radar

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Mount, G. J.; Comas, X.; Wright, W. J.; McClellan, M. D.

2014-12-01

Hydrogeologic characterization of karst limestone aquifers is difficult due to the variability in the spatial distribution of porosity and dissolution features. Typical methods for aquifer investigation, such as drilling and pump testing, are limited by the scale or spatial extent of the measurement. Hydrogeophysical techniques such as ground penetrating radar (GPR) can provide indirect measurements of aquifer properties and be expanded spatially beyond typical point measures. This investigation used a multiscale approach to identify and quantify porosity distribution in the Miami Limestone, the lithostratigraphic unit that composes the uppermost portions of the Biscayne Aquifer in Miami Dade County, Florida. At the meter scale, laboratory measures of porosity and dielectric permittivity were made on blocks of Miami Limestone using zero offset GPR, laboratory and digital image techniques. Results show good correspondence between GPR and analytical porosity estimates and show variability between 22 and 66 %. GPR measurements at the field scale 10-1000 m investigated the bulk porosity of the limestone based on the assumption that a directly measured water table would remain at a consistent depth in the GPR reflection record. Porosity variability determined from the changes in the depth to water table resulted in porosity values that ranged from 33 to 61 %, with the greatest porosity variability being attributed to the presence of dissolution features. At the larger field scales, 100 - 1000 m, fitting of hyperbolic diffractions in GPR common offsets determined the vertical and horizontal variability of porosity in the saturated subsurface. Results indicate that porosity can vary between 23 and 41 %, and delineate potential areas of enhanced recharge or groundwater / surface water interactions. This study shows porosity variability in the Miami Limestone can range from 22 to 66 % within 1.5 m distances, with areas of high macroporosity or karst dissolution features

Vertical small scale variations of sorption and mineralization of three herbicides in subsurface limestone and sandy aquifer

Science.gov (United States)

Janniche, G. S.; Mouvet, C.; Albrechtsen, H.-J.

2011-04-01

Vertical variation in sorption and mineralization potential of mecoprop (MCPP), isoproturon and acetochlor were investigated at low concentrations (μg-range) at the cm-scale in unsaturated sub-surface limestone samples and saturated sandy aquifer samples from an agricultural catchment in Brévilles, France. From two intact core drills, four heterogenic limestone sections were collected from 4.50 to 26.40 m below surface (mbs) and divided into 12 sub-samples of 8-25 cm length, and one sandy aquifer section from 19.20 to 19.53 m depth divided into 7 sub-samples of 4-5 cm length. In the sandy aquifer section acetochlor and isoproturon sorption increased substantially with depth; in average 78% (acetochlor) and 61% (isoproturon) per 5 cm. Also the number of acetochlor and isoproturon degraders (most-probable-number) was higher in the bottom half of the aquifer section (93-> 16 000/g) than in the upper half (4-71/g). One 50 cm long limestone section with a distinct shift in color showed a clear shift in mineralization, number of degraders and sorption: In the two brown, uppermost samples, up to 31% mecoprop and up to 9% isoproturon was mineralized during 231 days, the numbers of mecoprop and isoproturon degraders were 1300 to > 16 000/g, and the sorption of both isoproturon and acetochlor was more than three times higher, compared to the two deeper, grayish samples just below where mineralization (≤ 4%) and numbers of degraders (1-520/g) were low for all three herbicides. In both unsaturated limestone and sandy aquifer, variations and even distinct shifts in both mineralization, number of specific degraders and sorption were seen within just 4-15 cm of vertical distance. A simple conceptual model of herbicides leaching to groundwater through a 10 m unsaturated limestone was established, and calculations showed that a 30 cm active layer with the measured sorption and mineralization values hardly impacted the fate of the investigated herbicides, whereas a total

Hydraulic retention time on vinasse stabilisation with limestone in the acidogenic phase of anaerobic digestion

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Ismael Plácido Tomielis

Full Text Available ABSTRACT: The main problem in anaerobic digestion of low-protein residues is the instability caused acidity. The use of limestone at the same time as a neutralizing agent and support material is innovative because stones wear allows the slow release of the calcium carbonate thereby eliminating dispersers. Free calcium content in the system was measured in two plug flow reactors filled with vinasse at initial pH of 4.50. The proportion of 1.8 tonnes of limestone per m³ of vinasse was evaluated at the Hydraulic Retention Times (HRT of 24, 48, 72, 96 and 120 hours, allowing stabilisation at 96 hours. The ratio of Volatile Acids/Total Alkalinity (VA/TA ranged from 0.2 to 0.4 and the pH reached 7.0, at the HRT of 120 hours. Increasing the HRT also increased the volatile total solids (VTS and fixed total solids (TFS in a similar profile to the measured free calcium content, but calcium remained at the appropriate level of 100 to 250mg l-1. The proportion of limestone/vinasse was adequate to ensure stabilisation, but it is not recommended to reduce the HRT below 96 hours due to the risk of compromising the stability of the anaerobic system.

Treatment Of Metal-Mine Effluents By Limestone Neutralization And Calcite Co-Precipitation (Presentation)

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The U.S. Geological Survey - Leetown Science Center and the Colorado School of Mines have developed a remediation process for the treatment of metals in circumneutral mining influenced waters. The process involves treatment with a pulsed limestone bed (PLB) system, followed by c...

Comparison of different modeling approaches to simulate contaminant transport in a fractured limestone aquifer

DEFF Research Database (Denmark)

Mosthaf, Klaus; Rosenberg, L.; Balbarini, Nicola

. Given available field data and model purpose, this paper therefore aims to develop, examine and compare modeling approaches for transport of contaminants in fractured limestone aquifers. The model comparison was conducted for a contaminated site in Denmark, where a plume of a dissolved contaminant (PCE...... was combined with an analysis of heterogeneities and fractures from a nearby excavation (analog site). Methods for translating the geological information and fracture mapping into each of the model concepts were examined. Each model was compared with available field data, considering both model fit...... of field data is the determination of relevant hydraulic properties and interpretation of aqueous and solid phase contaminant concentration sampling data. Traditional water sampling has a bias towards fracture sampling, however concentrations in the limestone matrix are needed for assessing contaminant...

Predicted osteotomy planes are accurate when using patient-specific instrumentation for total knee arthroplasty in cadavers: a descriptive analysis.

Science.gov (United States)

Kievit, A J; Dobbe, J G G; Streekstra, G J; Blankevoort, L; Schafroth, M U

2018-06-01

Malalignment of implants is a major source of failure during total knee arthroplasty. To achieve more accurate 3D planning and execution of the osteotomy cuts during surgery, the Signature (Biomet, Warsaw) patient-specific instrumentation (PSI) was used to produce pin guides for the positioning of the osteotomy blocks by means of computer-aided manufacture based on CT scan images. The research question of this study is: what is the transfer accuracy of osteotomy planes predicted by the Signature PSI system for preoperative 3D planning and intraoperative block-guided pin placement to perform total knee arthroplasty procedures? The transfer accuracy achieved by using the Signature PSI system was evaluated by comparing the osteotomy planes predicted preoperatively with the osteotomy planes seen intraoperatively in human cadaveric legs. Outcomes were measured in terms of translational and rotational errors (varus, valgus, flexion, extension and axial rotation) for both tibia and femur osteotomies. Average translational errors between the osteotomy planes predicted using the Signature system and the actual osteotomy planes achieved was 0.8 mm (± 0.5 mm) for the tibia and 0.7 mm (± 4.0 mm) for the femur. Average rotational errors in relation to predicted and achieved osteotomy planes were 0.1° (± 1.2°) of varus and 0.4° (± 1.7°) of anterior slope (extension) for the tibia, and 2.8° (± 2.0°) of varus and 0.9° (± 2.7°) of flexion and 1.4° (± 2.2°) of external rotation for the femur. The similarity between osteotomy planes predicted using the Signature system and osteotomy planes actually achieved was excellent for the tibia although some discrepancies were seen for the femur. The use of 3D system techniques in TKA surgery can provide accurate intraoperative guidance, especially for patients with deformed bone, tailored to individual patients and ensure better placement of the implant.

Mini-Mental Status Examination: a short form of MMSE was as accurate as the original MMSE in predicting dementia

DEFF Research Database (Denmark)

Schultz-Larsen, Kirsten; Lomholt, Rikke Kirstine; Kreiner, Svend

2006-01-01

.4%), and positive predictive value (71.0%) but equal area under the receiver operating characteristic curve. Cross-validation on follow-up data confirmed the results. CONCLUSION: A short, valid MMSE, which is as sensitive and specific as the original MMSE for the screening of cognitive impairments and dementia......OBJECTIVES: This study assesses the properties of the Mini-Mental State Examination (MMSE) with the purpose of improving the efficiencies of the methods of screening for cognitive impairment and dementia. A specific purpose was to determine whether an abbreviated version would be as accurate...... is attractive for research and clinical practice, particularly if predictive power can be enhanced by combining the short MMSE with neuropsychological tests or informant reports....

Minimising Backbreak at the Dewan Cement Limestone Quarry Using an Artificial Neural Network

Science.gov (United States)

Muhammad, Khan; Shah, Akram

2017-12-01

Backbreak, defined as excessive breakage behind the last row of blastholes in blasting operations at a quarry, causes destabilisation of rock slopes, improper fragmentation, minimises drilling efficiency. In this paper an artificial neural network (ANN) is applied to predict backbreak, using 12 input parameters representing various controllable factors, such as the characteristics of explosives and geometrical blast design, at the Dewan Cement limestone quarry in Hattar, Pakistan. This ANN was trained with several model architectures. The 12-2-1 ANN model was selected as the simplest model yielding the best result, with a reported correlation coefficient of 0.98 and 0.97 in the training and validation phases, respectively. Sensitivity analysis of the model suggested that backbreak can be reduced most effectively by reducing powder factor, blasthole inclination, and burden. Field tests were subsequently carried out in which these sensitive parameters were varied accordingly; as a result, backbreak was controlled and reduced from 8 m to less than a metre. The resulting reduction in powder factor (kg of explosives used per m3 of blasted material) also reduced blasting costs.

Faults architecture and growth in clay-limestone alternation. Examples in the S-E Basin alternations (France) and numerical modeling

International Nuclear Information System (INIS)

Roche, Vincent

2011-01-01

The following work has been carried out in the framework of the studies conducted by IRSN in support of its safety evaluation of the geological disposal programme of high and intermediate level, long-lived radioactive waste. Such a disposal is planned to be hosted by the Callovian-Oxfordian indurate clay formation between two limestone formations in eastern Paris basin, France. Hypothetical faults may cross-cut this layered section, decreasing the clay containment ability by creating preferential pathways for radioactive solute towards limestones. This study aims at characterising the fault architecture and the normal fault growth in clay/limestone layered sections. Structural analysis and displacement profiles have been carried out in normal faults crossing several decimetres to metre thick sedimentary alternations in the South-Eastern Basin (France) and petrophysical properties have been determined for each layer. The studied faults are simple fault planes or complex fault zones showing are significantly controlled by the layering. The analysis of the fault characteristics and the results obtained on numerical models enlighten several processes such as fault nucleation, fault restriction, and fault growth through layered section. Some studied faults nucleated in the limestone layers, without using pre-existing fractures such as joints, and according to our numerical analysis, a strong stiffness, a low strength contrast between the limestone and the clay layer, and/or s a greater thickness of the clay layer are conditions which favour nucleation of faults in limestone. The range of mechanical properties leading to the fault nucleation in one layer type or another was investigated using a 3D modelling approach. After its nucleation, the fault propagates within a homogeneous medium with a constant displacement gradient until its vertical propagation is stopped by a restrictor. The evidenced restrictors are limestone-clay interfaces or faults in clays, sub

Deformation, Failure, and Fatigue Life of SiC/Ti-15-3 Laminates Accurately Predicted by MAC/GMC

Science.gov (United States)

Bednarcyk, Brett A.; Arnold, Steven M.

2002-01-01

NASA Glenn Research Center's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) (ref.1) has been extended to enable fully coupled macro-micro deformation, failure, and fatigue life predictions for advanced metal matrix, ceramic matrix, and polymer matrix composites. Because of the multiaxial nature of the code's underlying micromechanics model, GMC--which allows the incorporation of complex local inelastic constitutive models--MAC/GMC finds its most important application in metal matrix composites, like the SiC/Ti-15-3 composite examined here. Furthermore, since GMC predicts the microscale fields within each constituent of the composite material, submodels for local effects such as fiber breakage, interfacial debonding, and matrix fatigue damage can and have been built into MAC/GMC. The present application of MAC/GMC highlights the combination of these features, which has enabled the accurate modeling of the deformation, failure, and life of titanium matrix composites.

Limited Sampling Strategy for Accurate Prediction of Pharmacokinetics of Saroglitazar: A 3-point Linear Regression Model Development and Successful Prediction of Human Exposure.

Science.gov (United States)

Joshi, Shuchi N; Srinivas, Nuggehally R; Parmar, Deven V

2018-03-01

Our aim was to develop and validate the extrapolative performance of a regression model using a limited sampling strategy for accurate estimation of the area under the plasma concentration versus time curve for saroglitazar. Healthy subject pharmacokinetic data from a well-powered food-effect study (fasted vs fed treatments; n = 50) was used in this work. The first 25 subjects' serial plasma concentration data up to 72 hours and corresponding AUC 0-t (ie, 72 hours) from the fasting group comprised a training dataset to develop the limited sampling model. The internal datasets for prediction included the remaining 25 subjects from the fasting group and all 50 subjects from the fed condition of the same study. The external datasets included pharmacokinetic data for saroglitazar from previous single-dose clinical studies. Limited sampling models were composed of 1-, 2-, and 3-concentration-time points' correlation with AUC 0-t of saroglitazar. Only models with regression coefficients (R 2 ) >0.90 were screened for further evaluation. The best R 2 model was validated for its utility based on mean prediction error, mean absolute prediction error, and root mean square error. Both correlations between predicted and observed AUC 0-t of saroglitazar and verification of precision and bias using Bland-Altman plot were carried out. None of the evaluated 1- and 2-concentration-time points models achieved R 2 > 0.90. Among the various 3-concentration-time points models, only 4 equations passed the predefined criterion of R 2 > 0.90. Limited sampling models with time points 0.5, 2, and 8 hours (R 2 = 0.9323) and 0.75, 2, and 8 hours (R 2 = 0.9375) were validated. Mean prediction error, mean absolute prediction error, and root mean square error were prediction of saroglitazar. The same models, when applied to the AUC 0-t prediction of saroglitazar sulfoxide, showed mean prediction error, mean absolute prediction error, and root mean square error model predicts the exposure of

Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean

Energy Technology Data Exchange (ETDEWEB)

Dan Golomb; Eugene Barry; David Ryan; Carl Lawton; Stephen Pennell; Peter Swett; Huishan Duan; Michael Woods

2005-11-01

This semi-annual progress reports includes further findings on CO{sub 2}-in-Water (C/W) emulsions stabilized by fine particles. In previous semi-annual reports we described the formation of stable C/W emulsions using pulverized limestone (CaCO{sub 3}), flyash, beach sand, shale and lizardite, a rock rich in magnesium silicate. For the creation of these emulsions we used a High-Pressure Batch Reactor (HPBR) equipped with view windows for illumination and video camera recording. For deep ocean sequestration, a C/W emulsion using pulverized limestone may be the most suitable. (a) Limestone (mainly CaCO{sub 3}) is cheap and plentiful; (b) limestone is innocuous for marine organisms (in fact, it is the natural ingredient of shells and corals); (c) it buffers the carbonic acid that forms when CO{sub 2} dissolves in water. For large-scale sequestration of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion a device is needed that mixes the ingredients, liquid carbon dioxide, seawater, and a slurry of pulverized limestone in seawater continuously, rather than incrementally as in a batch reactor. A practical mixing device is a Kenics-type static mixer. The static mixer has no moving parts, and the shear force for mixing is provided by the hydrostatic pressure of liquid CO{sub 2} and CaCO{sub 3} slurry in the delivery pipes from the shore to the disposal depth. This semi-annual progress report is dedicated to the description of the static mixer and the results that have been obtained using a bench-scale static mixer for the continuous formation of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion. The static mixer has an ID of 0.63 cm, length 23.5 cm, number of baffles 27. Under pressure, a slurry of CaCO{sub 3} in artificial seawater (3.5% by weight NaCl) and liquid CO{sub 2} are co-injected into the mixer. From the mixer, the resulting emulsion flows into a Jerguson cell with two oblong windows on opposite sides, then it is vented. A fully ported ball valve inserted after the Jerguson

Limestones in Treinta y Tres district : Aerial photo of Jose P. Varela - Isla Patrulla

International Nuclear Information System (INIS)

Coronel, N.; Heinzen, W.

1981-01-01

This work brings information of fields and laboratory samples about the outcrop in Treinta y Tres district in the framework of limestones programme carried out jointly with I.G.U and BGR through the geological German mission

Evaluating macroinvertebrate community shifts in the confluence of freestone and limestone streams

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Jennifer K. Hellmann

2014-07-01

Full Text Available Aquatic macroinvertebrates are critical to ecosystem functioning through their regulation of many essential top-down and bottom-up ecosystem processes such as energy translocation, nutrient flow, and detrital decomposition. However, specific preferences by macroinvertebrates for certain ranges of abiotic and biotic characteristics mean that changes in these factors often create large differences in benthic community structure. Investigations into drivers of community structure have found distinct patterns of variation between ecosystems, but drivers of macroscale variation may differ from drivers of microscale variation. Such microscale variation in macroinvertebrate community structure as a function of abiotic conditions may be found in the confluence of two geologically distinct freshwater streams. Variation in the origin, underlying bedrock, and watershed of a stream results in drastically different physical and chemical characteristics and correspondingly distinct macroinvertebrate community structures. In areas where water from geologically distinct streams flows together, a mixing zone emerges with unique chemical and physical characteristics. There is little information on how invertebrate communities are structured within this mixing zone. To investigate this, we examined how the structure of the macroinvertebrate community changed downstream of the confluence. Up to thirty metres downstream, we found distinct stream sections that mirrored physical and chemical conditions found in limestone and freestone streams, and a mixing zone with emergent properties. These physical and chemical changes between sites were accompanied by shifts in macroinvertebrate community composition. Diversity indices indicated significantly higher diversity in freestone sites than in limestone sites or the mixing zone and there was a unique composition of genera in the mixing zone that were distinct from both limestone and freestone sites. Factors driving

Influence of humic substances on electrochemical degradation of trichloroethylene in limestone aquifers

International Nuclear Information System (INIS)

Rajic, Ljiljana; Fallahpour, Noushin; Nazari, Roya; Alshawabkeh, Akram N.

2015-01-01

Highlights: • Humic substances (HS) adversely affect TCE electrochemical reduction. • The inverse correlation between HS content and TCE removal is linear. • HS interfere with the hydrodechlorination of TCE at the cathode. • The impact of HS on TCE removal was reduced in the presence of limestone gravel. - Abstract: In this study we investigate the influence of humic substances (HS) on electrochemical transformation of trichloroethylene (TCE) in groundwater from limestone aquifers. A laboratory flow-through column with an electrochemical reactor that consists of a palladized iron foam cathode followed by a MMO anode was used to induce TCE electro-reduction in groundwater. Up to 82.9% TCE removal was achieved in the absence of HS. Presence of 1, 2, 5, and 10 mgTOC L −1 reduced TCE removal to 70.9%, 61.4%, 51.8% and 19.5%, respectively. The inverse correlation between HS content and TCE removal was linear. Total organic carbon (TOC), dissolved organic carbon (DOC) and absorption properties (A = 254 nm, 365 nm and 436 nm) normalized to DOC, were monitored during treatment to understand the behavior and impacts of HS under electrochemical processes. Changes in all parameters occurred mainly after contact with the cathode, which implies that the HS are reacting either directly with electrons from the cathode or with H 2 formed at the cathode surface. Since hydrodechlorination is the primary TCE reduction mechanism in this setup, reactions of the HS with the cathode limit transformation of TCE. The presence of limestone gravel reduced the impact of HS on TCE removal. The study concludes that presence of humic substances adversely affects TCE removal from contaminated groundwater by electrochemical reduction using palladized cathodes.

Source and depositional processes of coarse-grained limestone event beds in Frasnian slope deposits (Kostomłoty-Mogiłki quarry, Holy Cross Mountains, Poland)

Science.gov (United States)

Vierek, Aleksandra

2010-10-01

The Kostomłoty-Mogiłki succession is situated in the Kostomłoty transitional zone between the shallow-water Kielce stromatoporoid-coral platform and the deeper Łysogóry basin. In the Kostomłoty-Mogiłki quarry, the upper part of the Szydłówek Beds and Kostomłoty Beds are exposed. The Middle-Upper Frasnian Kostomłoty Beds are composed of shales, micritic and nodular limestones with abundant intercalations of detrital limestones. The dark shales and the micritic and nodular limestones record background sedimentation. The interbedded laminated and detrital limestones reflect high-energy deposition (= event beds). These event beds comprise laminated calcisiltites, fine-grained calcarenites, coarse-grained grain-supported calcirudites fabrics, and matrix-supported calcirudites. The material of these event beds was supplied by both erosion of the carbonate-platform margin and cannibalistic erosion of penecontemporaneous detrital limestones building the slope of this platform. Storms and the tectonic activity were likely the main causes of erosion. Combined and gravity flows were the transporting mechanisms involved in the reworking and redeposition.

Technical Feseability Study and Economic Development of Limestone at Pelawi Hill by PT. Semen Baturaja (Tbk. in Ogan Komering Ulu Distric of South Sumatra

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Subagio Badirun

2018-03-01

Full Text Available Limestone mining for cement is increasing in Indonesia, and has been specifically included in the strategic plan of PT. Semen Baturaja (Persero Tbk. By expanding the limestone mining in Bukit Pelawi, OganKomering Ulu Regency. From the mine, the Company targets 2,000,000 tons of limestone per year to support the plan to increase cement production to 3.4 million tons per year from 1.5 million tons per year.  This study makes a technical and economic assessment of the Company's action plan. Based on detailed exploration drilling conducted, it has identified limestone sources of 80.3 million tons and 43.4 million tons of mining reserves. The quality of limestone composite in the mine by Company’s is CaO> 43% and RCO3> 78%. The value of Cut of Grade (COG which is still categorized by ore is CaO at 30% and RCO3 is 70%.  The results of this study indicate the assumption of the selling value of limestone with composite quality of Rp. 48,500 per ton with a maximum production rate of 2 million tons per year, still provides eligibility criteria for all investment parameters calculated showing IRR 13.72%, NPV (+ Rp 5,111,313,765.-, PBP for 6.42 years. The effect of increasing or decreasing cement price assumption and operational cost ± 1.5%, will give a significant effect on the rate of return on the calculation of this study.

Geological mapping and analysis in determining resource recitivity limestone rocks in the village of Mersip and surrounding areas, district Limun, Sorolangun Regency, Jambi Province

Science.gov (United States)

Dona, Obie Mario; Ibrahim, Eddy; Susilo, Budhi Kuswan

2017-11-01

The research objective is to describe potential, to analyze the quality and quantity of limestone, and to know the limit distribution of rocks based on the value of resistivity, the pattern of distribution of rocks by drilling, the influence mineral growing on rock against resistivity values, the model deposition of limestone based on the value resistivity of rock and drilling, and the comparison between the interpretation resistivity values based on petrographic studies by drilling. Geologic Formations study area consists of assays consisting of altered sandstone, phyllite, slate, siltstone, grewake, and inset limestone. Local quartz sandstone, schist, genealogy, which is Member of Mersip Stylists Formation, consists of limestone that formed in shallow seas. Stylists Formation consists of slate, shale, siltstone and sandstone. This research methodology is quantitative using experimental observation by survey. This type of research methodology by its nature is descriptive analysis.

Biological effects of long term fine limestone tailings discharge in a fjord ecosystem.

Science.gov (United States)

Brooks, Lucy; Melsom, Fredrik; Glette, Tormod

2015-07-15

Benthic infaunal data collected from 1993 to 2010 were analysed to examine the effect of long term discharge of fine limestone tailings on macrofaunal species assemblages in a fjord. Relative distance from the outfall and proportion of fine tailings in the sediment were correlated with benthic community structure. Diversity decreased with increasing proportion of fine tailings. Biological Traits Analysis (BTA) was used to explore the temporal and spatial effects of the tailings gradient on macrofaunal functional attributes. BTA revealed that all stations along a pressure gradient of fine limestone tailings were dominated by free-living species. As the proportion of fine tailings in the sediment increased, there was an increase in fauna that were smaller, highly mobile, living on or nearer the surface sediment, with shorter lifespans. There was a decrease in permanent tube dwellers, those fauna with low or no mobility, that live deeper in the sediment and have longer lifespans (>5 yrs). Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of limestone balance from statistical data of the German Federal Institute for Geosciences and Natural Resources. Emissions reporting in accordance with the Framework Convention on Climate Change and the Kyoto Protocol (Category CRF 2.A.3); Ableitung der Kalksteinbilanz aus den statistischen Daten der Bundesanstalt fuer Geowissenschaften und Rohstoffe. Emissionsberichterstattung nach Klimarahmenkonvention und Kyoto-Protokoll (Kategorie CRF 2.A.3)

Energy Technology Data Exchange (ETDEWEB)

Roehling, Simone [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany); Kludt, Robert [Umweltbundesamt, Dessau (Germany)

2010-11-15

Balances are possible on the basis of statistical data or on the basis of indicators. The indicator-based approach in combination with the irreplaceable statistical balance items would seem to be more appropriate from a technical point of view. The balance calculations should however only be used to provide an overview of limestone use, i.e. they should only be used to verify the activity data8. The emission calculations should always be made in the source groups in which limestone is used. This also makes it possible to take account of all emissionrelevant carbonates in the source groups, which results in much more accurate calculations. (orig.)

The effect of surface finishes on outdoor granite and limestone pavers

Directory of Open Access Journals (Sweden)

Martínez-Martínez, J.

2008-06-01

Full Text Available Two types of ornamental stones, namely granite (Blanco Rafaela or Zarzalejo Granite and microcrystalline limestone (marble known commercially as Gris Pulpis, treated for different surface finishes, were tested for suitability as paving slabs. The finishes tested in both stones were polishing, hammering, honing and flaming, while acid treatment and abrasion were applied to limestone only and sawn finishes were only studied in granite.The stones were tested for the three physical properties that determine suitability for use as paving slabs; flexural strength under a concentrated load, and abrasion and slip resistance. Laboratory freeze-thaw cycle ageing tests were also conducted and flexural strength subsequently evaluated. Stone water sorption proved to be substantially unaltered by the type of finish employed. Finish barely affected flexural strength, except in the case of limestone flaming, where it was lower. Hammering was found to provide good slip resistance in both stones. The best slip performance for granite, however, was found for flamed specimens. Finish was shown to have no effect on abrasion resistance in either of the stone materials. Polished limestone suffered the least damage in freeze-thaw cycles, whereas freeze-thaw resistance was similar in all the granite specimens, regardless of the finish used.Se han estudiado, para su utilización como baldosas de pavimentos, granito (Blanco Rafaela o Granito de Zarzalejo y caliza microcristalina (mármol comercial Gris Pulpis con diferentes acabados. Estos acabados son: pulido, apomazado, abujardado y flameado en ambas rocas y además acabado al ácido y amolado en la caliza. Se han determinado mediante ensayos estandarizados las tres propiedades físicas de mayor interés para el uso de la piedra natural como baldosa en pavimentos de exteriores: resistencia a la flexión bajo carga concentrada, a la abrasión y al deslizamiento. Se han realizado ensayos de durabilidad por ciclos de hielo

Do Skilled Elementary Teachers Hold Scientific Conceptions and Can They Accurately Predict the Type and Source of Students' Preconceptions of Electric Circuits?

Science.gov (United States)

Lin, Jing-Wen

2016-01-01

Holding scientific conceptions and having the ability to accurately predict students' preconceptions are a prerequisite for science teachers to design appropriate constructivist-oriented learning experiences. This study explored the types and sources of students' preconceptions of electric circuits. First, 438 grade 3 (9 years old) students were…

RNA-based molecular survey of biodiversity of limestone tombstone microbiota in response to atmospheric sulphur pollution.

Science.gov (United States)

Villa, F; Vasanthakumar, A; Mitchell, R; Cappitelli, F

2015-01-01

Outdoor stoneworks sustain biofilm formation and are constantly at risk of deterioration by micro-organisms. In this study, the biofilm microflora of historic limestone tombstones located in a highly polluted urban environment (Cambridge, MA) and in a less polluted location (Lexington, MA) were compared using comprehensive RNA-based molecular analyses of 16S rRNA gene sequences as well as sequences of genes for different pathways of sulphur metabolism (soxB, apsA, dsrA). The metabolically active micro-organisms detected by denaturing gradient gel electrophoresis analysis of 16S rRNA fragments were predominantly represented by cyanobacteria (belonging to the family Nostocaceae and to the genus Chroococcidiopsis) in both polluted and unpolluted environments. The investigation of soxB, apsA, dsrA transcripts reflected the abundance and the diversity of sulphur-oxidizing and sulphate-reducing bacteria in the Cambridge samples in comparison with the Lexington samples. The investigation revealed that in addition to phototrophic sulphur bacteria belonging to the genera Thiocapsa, Halochromatium, Allochromatium, Thiococcus and Thermochromatium, other sulphate-oxidizing prokaryotes (e.g. the genus Thiobacillus) as well as sequences of Deltaproteobacteria from the genus Desulfovibrio occurred at the polluted urban site. The interactions between the main functional groups retrieved from the limestone tombstones were discussed. The biofilm microflora inhabiting historic limestones are a multi-component open ecosystem sensitively reacting to all environmental factors including air pollutants. Little is known about specific target groups that are active in the biofilm and their physiological functions. For the first time, transcripts involved in important energy-yielding processes were investigated to reveal the metabolic capabilities of the microflora in response to atmospheric sulphur pollution. This work provides novel and important information about the ecology of limestone

Stability of an anaerobic single reactor filled with dolomitic limestone with increased organic load of sugarcane

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Maria Magdalena Ribas Döll

2017-12-01

Full Text Available The anaerobic single-stage reactor was evaluated to treat vinasse and to evaluate its stability. This bench reactor was filled with dolomitic limestone with a horizontal plug flow to simulate a drainage channel. The experiment lasted 129 days while the reactor was submitted to different applied organic concentrations (chronologically applied: 3.0; 5.0; 12.0; 9.0 and 7.5 g L-1 as COD, chemical oxygen demand. COD removals were 50% and 9% with 3.0 and 7.5 g L-1, respectively. With 12.0 g L-1, reactor efficiency increased to 33%, with an abrupt drop to 3% on the 84th day. Therefore, in order to avoid reactor collapse, a remedial measure was necessary. The system remained in batch without feeding for 19 days (from the 85th to the 104th day with 9.0 g L-1. Afterwards, it was observed that the performance of the system tended to stabilize, reaching 47% with 7.5 g L-1 in the 118th day. At the end of the experiment, the potassium content of the wastewater decreased from 800 mg L-1 to 594 mg L-1 (on an average 25% and calcium and magnesium increased within the reactor liquor. The dissolution of the limestone inside the liquor reactor probably caused this result. After the treatment with limestone, the average pH value of the effluent increased from 4.9 to over 6.0 in all organic concentrations. It could be concluded that the reactor filled with dolomitic limestone in these operational conditions assured a low efficiency in COD removal, potassium reduction, increasing values of pH, alkalinity, calcium and magnesium. The instability was observed when there was increase in organic load to 12 g L-1 with subsequent recovery.

An Alternative Quality Control Technique for Mineral Chemistry Analysis of Portland Cement-Grade Limestone Using Shortwave Infrared Spectroscopy

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Nasrullah Zaini

2016-11-01

Full Text Available Shortwave infrared (SWIR spectroscopy can be applied directly to analyze the mineral chemistry of raw or geologic materials. It provides diagnostic spectral characteristics of the chemical composition of minerals, information that is invaluable for the identification and quality control of such materials. The present study aims to investigate the potential of SWIR spectroscopy as an alternative quality control technique for the mineral chemistry analysis of Portland cement-grade limestone. We used the spectroscopic (wavelength position and depth of absorption feature and geochemical characteristics of limestone samples to estimate the abundance and composition of carbonate and clay minerals on rock surfaces. The depth of the carbonate (CO3 and Al-OH absorption features are linearly correlated with the contents of CaO and Al2O3 in the samples, respectively, as determined by portable X-ray fluorescence (PXRF measurements. Variations in the wavelength position of CO3 and Al-OH absorption features are related to changes in the chemical compositions of the samples. The results showed that the dark gray and light gray limestone samples are better suited for manufacturing Portland cement clinker than the dolomitic limestone samples. This finding is based on the CaO, MgO, Al2O3, and SiO2 concentrations and compositions. The results indicate that SWIR spectroscopy is an appropriate approach for the chemical quality control of cement raw materials.

Crystal Graph Convolutional Neural Networks for an Accurate and Interpretable Prediction of Material Properties

Science.gov (United States)

Xie, Tian; Grossman, Jeffrey C.

2018-04-01

The use of machine learning methods for accelerating the design of crystalline materials usually requires manually constructed feature vectors or complex transformation of atom coordinates to input the crystal structure, which either constrains the model to certain crystal types or makes it difficult to provide chemical insights. Here, we develop a crystal graph convolutional neural networks framework to directly learn material properties from the connection of atoms in the crystal, providing a universal and interpretable representation of crystalline materials. Our method provides a highly accurate prediction of density functional theory calculated properties for eight different properties of crystals with various structure types and compositions after being trained with 1 04 data points. Further, our framework is interpretable because one can extract the contributions from local chemical environments to global properties. Using an example of perovskites, we show how this information can be utilized to discover empirical rules for materials design.

Temperatures and locations used by hibernating bats, including Myotis sodalis (Indiana bat), in a limestone mine: implications for conservation and management.

Science.gov (United States)

Brack, Virgil

2007-11-01

Understanding temperatures used by hibernating bats will aid conservation and management efforts for many species. A limestone mine with 71 km of passages, used as a hibernaculum by approximately 30,000 bats, was visited four times during a 6-year period. The mine had been surveyed and mapped; therefore, bats could be precisely located and temperatures (T (s)) of the entire hibernaculum ceiling accurately mapped. It was predicted that bats should hibernate between 5 and 10 degrees C to (1) use temperatures that allow a near minimal metabolic rate, (2) maximize the duration of hibernation bouts, (3) avoid more frequent and prolonged arousal at higher temperatures, (4) avoid cold and freezing temperatures that require an increase in metabolism and a decrease in duration of hibernation bouts or that could cause death, and (5) balance benefits of a reduced metabolic rate and costs of metabolic depression. The distribution of each species was not random for location (P block walls and sheltered alcoves, which perhaps dampened air movement and temperature fluctuations. Myotis lucifugus (little brown myotis) hibernated in colder, more variable areas (X = 7.2 +/- 2.6 degrees C). Myotis septentrionalis (northern myotis), Pipistrellus subflavus (eastern pipistrelle), and Eptesicus fuscus (big brown bat) typically hibernated in warm, thermally stable areas (X = 9.1 +/- 0.2 degrees C, X = 9.6 +/- 1.9 degrees C, and X = 9.5 +/- 1.5 degrees C, respectively). These data do not indicate that hibernacula for M. sodalis, an endangered species, should be manipulated to cool below 5 degrees C.

Comparative Studies on Community Ecology of Two Types of Subtropical Forests Grown in Silicate and Limestone Habitats in the Northern Part of Okinawa Island, Japan

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S. M. Feroz

2008-06-01

Full Text Available In order to compare woody species diversity, spatial distribution of trees and stand structure on the basis of the architectural stratification between two types of subtropical forests in the northern part of Okinawa Island, Japan, tree censuses in a 750 m2 plot in silicate habitat and a 1000 m2 plot in limestone habitat were performed. It was found that both subtropical forests growing in silicate and limestone habitats consisted of four architectural layers. A total of 26 families, 43 genera, 60 species and 4684 individuals larger than 0.1 m high in the silicate habitat, and 31 families, 51 genera, 62 species and 4798 individuals larger than 0.0 m high in the limestone habitat, were recorded. As a result, the floristic composition in the silicate habitat was quite different from that in the limestone habitat in terms of similarity index ( Π C = 0.07; approximately only one-sixth of the species were in common. The floristic composition among layers was more similar in the silicate habitat than in the limestone habitat. Castanopsis sieboldii (Mak. Hatusima was the most dominant species in the silicate habitat, but was completely absent in the limestone habitat where Cinnamomum japonicum Sieb. ex Nees was the most dominant species. The potential number of species in the silicate forest (62 was lower than that in the limestone forest (71. However, the woody species diversity was higher in the silicate forest than in the limestone forest. The values of H′ and J′ tended to increase from the top layer downward except for the bottom layer in the silicate forest, while this increasing trend was reversed in the limestone forest. It follows that high woody species diversity in the silicate forest depended on small-sized trees, whereas in the limestone forest it depended on big-sized trees. The spatial distribution of trees in the forests was random in each layer, except the top layer, where there existed a double-clump structure. High degree of

Rare earths in the Leadville Limestone and its marble derivates

International Nuclear Information System (INIS)

Jarvis, J.C.; Wildeman, T.R.; Banks, N.G.

1975-01-01

Samples of unaltered and metamorphosed Leadville Limestone (Mississippian, Colorado) were analyzed by neutron activation for ten rare-earth elements (REE). The total abundance of the REE in the least-altered limestone is 4-12 ppm, and their distribution patterns are believed to be dominated by the carbonate minerals. The abundances of the REE in the marbles and their sedimentary precursors are comparable but the distribution patterns are not. Eu is enriched over the other REE in the marbles, and stratigraphically upward in the formation (samples located progressively further from the heat source), the light REE become less enriched relative to the heavy REE. The Eu anomaly is attributed to its ability, unique among the REE, to change from the 3+ to 2+ oxidation state. Whether this results in preferential mobilization of the other REE or whether this reflects the composition of the pore fluid during metamorphism is unknown. Stratigraphically selective depletion of the heavy REE may be attributed to more competition for the REE between fluid and carbonate minerals in the lower strata relative to the upper strata. This competition could have been caused by changes in the temperature of the pore fluid or to the greater resistance to solution of the dolomite in the lower parts of the formation than the calcite in the upper parts

Imobilisasi Tembaga (Cu dan Netralisasi Aktivitas Ion Hidrogen (pH pada Limbah Cair Industri Peleburan Emas Dengan Batu Gamping (Limestone

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Onny Setiani

2016-01-01

Full Text Available The objectives of this research were to determine the effectiveness of  limestones in neutralizing hydrogen ion activity (pH, immobilizing cooper (Cu and to implement a waste water treatment process from the gold molten industry using a cost-effective method to prevent the environment contamination from hazardous wastes. Before  implementing technology, a preliminary study was done to determine a simple and cost effective  method to neutralize pH, immobilize and sedimentation of Copper (Cu  using limestones (CaCO3. The results of laboratory examination in preliminary study  showed that limestones may decrease the concentration of Cu from 23,070 mg/L to 0.711 mg/L, TDS from 30,302 mgLl to 18,289 mg/L and neutralize pH from 1.0-3.0 to 7.0. This research demonstrate that limestones may provide a cost effective method to immobilize  Cu and neutralize contaminated wastewater of the gold molten industry. Since the technology  is very simple, it is  suggested  to be used by home scale or  small industry to protect the environment from toxic waste pollution.   Keywords: Immobilizing cooper, lime stone, neutralization, waste water.

Effect of the pre-treatment and the aggregate content on the adhesion strength of repair mortars on Miocene porous limestone

Science.gov (United States)

Szemerey-Kiss, Balázs; Török, Ákos

2016-04-01

The adhesion between porous limestone and newly prepared repair mortars are crucial in the preservation of historic stone structures. Besides mechanical compatibility other matches such as chemical composition and porosity are also essential, but the current research focuses on the adhesion strength of repair mortars that are used in the restoration of Hungarian porous limestone. 8 mortars (4 commercial and 4 specially prepared) were selected for the tests. Mortars with different amount of aggregate were prepared and caste to stone surface. The stone substrate was highly porous Miocene limestone. The strength was tested by standardized pull-out tests which method is commonly used for concrete testing. The limestone surfaces were either used in their natural conditions or were pre-treated (pre-wetting). The strength of the stone/mortar bond was tested. The failure mechanism was documented and various failure modes were identified. Strength test results suggest that especially pre-treatment influences strongly the pull-out strength at mortar/stone interface. Increasing aggregate content also reduces pull out strength of tested repair mortars, but at various rates depending on the mortar type. The financial support of OTKA post-doctoral grant to BSZK (reference number is: PD 112-955) and National Research, Development and Innovation (NKFI) Fund to ÁT (ref. no. K 116532) are appreciated.

Accurate X-Ray Spectral Predictions: An Advanced Self-Consistent-Field Approach Inspired by Many-Body Perturbation Theory.

Science.gov (United States)

Liang, Yufeng; Vinson, John; Pemmaraju, Sri; Drisdell, Walter S; Shirley, Eric L; Prendergast, David

2017-03-03

Constrained-occupancy delta-self-consistent-field (ΔSCF) methods and many-body perturbation theories (MBPT) are two strategies for obtaining electronic excitations from first principles. Using the two distinct approaches, we study the O 1s core excitations that have become increasingly important for characterizing transition-metal oxides and understanding strong electronic correlation. The ΔSCF approach, in its current single-particle form, systematically underestimates the pre-edge intensity for chosen oxides, despite its success in weakly correlated systems. By contrast, the Bethe-Salpeter equation within MBPT predicts much better line shapes. This motivates one to reexamine the many-electron dynamics of x-ray excitations. We find that the single-particle ΔSCF approach can be rectified by explicitly calculating many-electron transition amplitudes, producing x-ray spectra in excellent agreement with experiments. This study paves the way to accurately predict x-ray near-edge spectral fingerprints for physics and materials science beyond the Bethe-Salpether equation.

Development of a method to accurately calculate the Dpb and quickly predict the strength of a chemical bond

International Nuclear Information System (INIS)

Du, Xia; Zhao, Dong-Xia; Yang, Zhong-Zhi

2013-01-01

Highlights: ► A method from new respect to characterize and measure the bond strength is proposed. ► We calculate the D pb of a series of various bonds to justify our approach. ► A quite good linear relationship of the D pb with the bond lengths for series of various bonds is shown. ► Take the prediction of strengths of C–H and N–H bonds for base pairs in DNA as a practical application of our method. - Abstract: A new approach to characterize and measure bond strength has been developed. First, we propose a method to accurately calculate the potential acting on an electron in a molecule (PAEM) at the saddle point along a chemical bond in situ, denoted by D pb . Then, a direct method to quickly evaluate bond strength is established. We choose some familiar molecules as models for benchmarking this method. As a practical application, the D pb of base pairs in DNA along C–H and N–H bonds are obtained for the first time. All results show that C 7 –H of A–T and C 8 –H of G–C are the relatively weak bonds that are the injured positions in DNA damage. The significance of this work is twofold: (i) A method is developed to calculate D pb of various sizable molecules in situ quickly and accurately; (ii) This work demonstrates the feasibility to quickly predict the bond strength in macromolecules

Phylogenetic analyses of Begonia sect. Coelocentrum and allied limestone species of China shed light on the evolution of Sino-Vietnamese karst flora.

Science.gov (United States)

Chung, Kuo-Fang; Leong, Wai-Chao; Rubite, Rosario Rivera; Repin, Rimi; Kiew, Ruth; Liu, Yan; Peng, Ching-I

2014-12-01

The picturesque limestone karsts across the Sino-Vietnamese border are renowned biodiversity hotspot, distinguished for extremely high endemism of calciphilous plants restricted to caves and cave-like microhabitats that have functioned as biological refugia on the otherwise harsh habitats. To understand evolutionary mechanisms underlying the splendid limestone flora, dated phylogeny is reconstructed for Asian Begonia, a species-rich genus on limestone substrates represented by no less than 60 species in southern China, using DNA sequences of nrITS and chloroplast rpL16 intron. The sampling includes 94 Begonia species encompassing most major Asian clades with a special emphasized on Chinese species. Except for two tuberous deciduous species and a species with upright stems, a majority of Sino-Vietnamese limestone Begonia (SVLB), including sect. Coelocentrum (19 species sampled) and five species of sect. Diploclinium, Leprosae, and Petermannia, are rhizomatous and grouped in a strongly supported and yet internally poorly resolved clade (Clade SVLB), suggesting a single evolutionary origin of the adaptation to limestone substrates by rhizomatous species, subsequent species radiation, and a strong tendency to retain their ancestral niche. Divergence-time estimates indicate a late Miocene diversification of Clade SVLB, coinciding with the onset of the East Asian monsoon and the period of extensive karstification in the area. Based on our phylogenetic study, Begonia sect. Coelocentrum is recircumscribed and expanded to include other members of the Clade SVLB (sect. Diploclinium: B. cavaleriei, B. pulvinifera, and B. wangii; sect. Leprosae: B. cylindrica and B. leprosa; sect. Petermannia: B. sinofloribunda). Because species of Clade SVLB have strong niche conservatism to retain in their ancestral habitats in cave-like microhabitats and Begonia are generally poor dispersers prone to diversify allopatrically, we propose that extensive and continuous karstification of the

Penetration of molten core materials into basaltic and limestone concrete

International Nuclear Information System (INIS)

Sutherland, H.J.

1978-01-01

In conjunction with the small-scale, melt-concrete interaction tests being conducted at Sandia Laboratories, an acoustic technique has been used to monitor the penetration of molten core materials into basaltic and limestone concrete. Real time plots of the position of the melt/concrete interface have been obtained, and they illustrate that the initial penetration rate of the melt may be of the order of 80 mm/min. Phenomena deduced by the technique include a non-wetted melt/concrete interface

Flue gas desulfurization under simulated oxyfiring fluidized bed combustion conditions: The influence of limestone attrition and fragmentation

Energy Technology Data Exchange (ETDEWEB)

Scala, F.; Salatino, P. [CNR, Naples (Italy)

2010-01-01

Flue gas desulfurization by means of limestone injection under simulated fluidized bed oxyfiring conditions was investigated, with a particular focus on particle attrition and fragmentation phenomena. An experimental protocol was applied, based on the use of complementary techniques that had been previously developed for the characterization of attrition of sorbents in air-blown atmospheric fluidized bed combustors. The extent and pattern of limestone attrition by surface wear in the dense phase of a fluidized bed were assessed in bench scale fluidized bed experiments under simulated oxyfiring conditions. Sorbent samples generated during the oxyfiring tests were further characterized from the standpoint of fragmentation upon high velocity impact by means of a particle impactor. The experimental results were compared with those previously obtained with the same limestone under air-blown atmospheric fluidized bed combustion conditions. The profound differences in the attrition and fragmentation extents and patterns associated with oxyfiring as compared to air-blown atmospheric combustion and the role played by the different attrition/fragmentation paths were highlighted. In particular, it was noted that attrition could effectively enhance particle sulfation under oxyfiring conditions by continuously disclosing unconverted calcium to the sulfur-bearing atmosphere.

ECOLOGICAL STUDY IN TWO QUARRIED LIMESTONE KARST HILLS IN BOGOR WEST JAVA: VEGETATION STRUCTURE AND FLORISTIC COMPOSITION

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ANNISA SATYANTI

2010-10-01

Full Text Available Many species extinctions have probably gone unnoticed on limestone that was destroyed before they could be sampled. Unless biodiversity surveys are intensified, the true magnitude of extinctions will never be ascertained. The objectives of this study were to determine tree species composition of limestone hills in Nyungcung and Ciampea; to determine quantitatively the dominant and less dominant species and to quantify floristic structure of the two limestone hills. Value of richness (Menhinick and evenness in Nyungcung were 3.28 and 0.826 whilst in Ciampea were 3.29 and 0.823, respectively. In term of diversity (Shannon Wiener, Nyungcung seems to be more diverse than Ciampea as indicated by the higher value of diversity index. Nyungcung has 3.225 of diversity (Shannon Wiener index while Ciampea has 2.859. The floristic composition of two sites was significantly different and mostly comprised Moraceae, Rubiaceae, and Euphorbiaceae. However, the highest presence of species were Antidesma montanum (Euphorbiaceae and Chrysophyllum lanceolatum (Sapotaceae, and Pandanus sp. (Pandanaceae in Nyungcung, whereas in Ciampea, Harpullia arborea (Sapindaceae, Ophiorhhiza canescens (Rubiaceae, and Allophyllus cobbe (Sapindaceae. Macaranga rhizinoides, O. canescens, A. montanum, and Turpinia montana , respectively , gained the highest importance values.

Autogenous and drying shrinkage of sodium carbonate activated slag altered by limestone powder incorporation

NARCIS (Netherlands)

Yuan, B.; Yu, Q.L.; Dainese, E.; Brouwers, H.J.H.

2017-01-01

This paper aims to study the shrinkage mechanism of sodium carbonate activated slag containing limestone powder (LP). The workability, pore structure, reaction kinetics and strength development were characterized. The results show that the autogenous shrinkage increases when the dosage of LP is low

Transport and retention of 14C-perfluorooctanoic acid (PFOA) in saturated limestone and sand porous media: Effects of input concentration, ionic strength and cation type

Science.gov (United States)

Xueyan, L.; Gao, B.; Sun, Y.; Wu, J.

2017-12-01

Perfluorooctanoic acid (PFOA) has been used in a wide variety of industrial and consumer product applications. PFOA has been detected around the world at ng/L to μg/L levels in groundwater, and at ng/g levels in soil.The physicochemical properties of porous media were proven to play pivotal roles in determining the transport behavior of various pollutants. It is anticipated that physicochemical properties of porous media will strongly influence the transport behavior of PFOA. In addition, previous investigations have revealed that input concentration significantly influence the transport behavior of nanoparticles and antibiotics. Thus, this study was designed experimentally and fundamentally to gain insight into transport and retention of PFOA in various porous medias at different input concentrations, solution IS and cation type. Unlike in quartz sand porous media, the BTCs in limestone porous media exhibited increasing retention rate and high degree of tailing in limestone porous media. Results showed that higher relative retention occurred in limestone porous media than in quartz sand porous media under the same solution chemistry. This result was attributed to the less negative zeta-potentials, rougher surface and larger specific surface area, and the presence of hydroxyl groups and organic matters of limestone grains. Higher ionic strength and Ca2+ had little impact on the mobility of PFOA in quartz sand porous media, but significantly enhanced the retention of PFOA in limestone porous media. The difference is likely due to the compression of the electrical double layer, and the surface-charge neutralization and cation-bridging effect of Ca2+. Higher input concentration resulted in lower relative PFOA retention in limestone porous media, but the influence were insignificant in quartz sand porous media. This effect is likely because attachment sites in limestone responced to the variety of input concentration differently than quartz.

Sierra Elvira limestone: petrophysical characteristics of an Andalusian heritage stone

Directory of Open Access Journals (Sweden)

Valverde, I.

2008-06-01

Full Text Available “Sierra Elvira stone” is one of the ornamental building stones most widely used in the historical monuments of eastern Andalusia. A Liassic age limestone, it appears in the central section of the Baetic Mountains and more specifically in the Middle Subbaetic domain. While the most common variety is a crinoid limestone, a micritic limestone of the same age has also been quarried, albeit in much smaller quantities. These stones form very thick beds, up to nearly 5 m deep, that run in consistently parallel lines and have a dip angle that facilitates quarrying.With petrographic, physical and mechanical properties that ensure stone strength and durability, it is a high quality building material suitable for both structural and ornamental purposes. These properties can be attributed to the minimal open porosity and concomitant excellent water resistance that characterize the stone, as well as to its high mechanical strength and low textural anisotropy, both elastic and mechanical. With such attributes, the stone can be successfully used for any number of purposes, including decorative stonework (portals, fountains, plinths, structural members (column shafts and bases or urban curbing and paving. Intervention on Sierra de Elvira limestone structures should be limited to cleaning or repair, for consolidating or protective materials are scantly effective.La “Piedra de Sierra Elvira” constituye una de las piedras ornamentales más significativas del Patrimonio Arquitectónico de Andalucía Oriental. Es una roca caliza del Lias que aflora en el Subbético Medio del sector central de las Cordilleras Béticas. El litotipo más explotado es una caliza con crinoides, en bastante menor importancia se ha extraído también otra caliza micrítica de la misma edad. Los bancos son muy potentes, en algunos casos de más de 5 m, con un paralelismo constante y un buzamiento que favorece su explotación en los frentes de cantera.Sus caracter

Estimation of static parameters based on dynamical and physical properties in limestone rocks

Science.gov (United States)

Ghafoori, Mohammad; Rastegarnia, Ahmad; Lashkaripour, Gholam Reza

2018-01-01

Due to the importance of uniaxial compressive strength (UCS), static Young's modulus (ES) and shear wave velocity, it is always worth to predict these parameters from empirical relations that suggested for other formations with same lithology. This paper studies the physical, mechanical and dynamical properties of limestone rocks using the results of laboratory tests which carried out on 60 the Jahrum and the Asmari formations core specimens. The core specimens were obtained from the Bazoft dam site, hydroelectric supply and double-curvature arch dam in Iran. The Dynamic Young's modulus (Ed) and dynamic Poisson ratio were calculated using the existing relations. Some empirical relations were presented to estimate uniaxial compressive strength, as well as static Young's modulus and shear wave velocity (Vs). Results showed the static parameters such as uniaxial compressive strength and static Young's modulus represented low correlation with water absorption. It is also found that the uniaxial compressive strength and static Young's modulus had high correlation with compressional wave velocity and dynamic Young's modulus, respectively. Dynamic Young's modulus was 5 times larger than static Young's modulus. Further, the dynamic Poisson ratio was 1.3 times larger than static Poisson ratio. The relationship between shear wave velocity (Vs) and compressional wave velocity (Vp) was power and positive with high correlation coefficient. Prediction of uniaxial compressive strength based on Vp was better than that based on Vs . Generally, both UCS and static Young's modulus (ES) had good correlation with Ed.

Limestone-Concentrate-Pellet Roasting in wet Carbon Dioxide

Institute of Scientific and Technical Information of China (English)

1990-01-01

A roast process for treating chalcopyrite concentrate was developed. The investigation of the reaction of limestone-concentrate-pellet in a wet carbon dioxide flow was carried out by means of a thermogravimetric analysis (TGA) to determine at which temperatures the roasting reaction would take place. The thermodynamic calculations on the roast reaction were made by the use of SOLGASMIX-PV program. The TGA curves and thermodynamic calculations indicated that the conversion of chalcopyrite into bornite took place at about 975K, and the conversion of bornite into chalcocite at 1065-1123K. The thermodynamic calculations also showed that the sulfur released was fixed as calcium sulfide within roasted pellets. X-ray diffraction examination identified these phases in products.

Economical assessment of competitive enhanced limestones for CO2 capture cycles in power plants

International Nuclear Information System (INIS)

Romeo, Luis M.; Lara, Yolanda; Lisbona, Pilar; Martinez, Ana

2009-01-01

CO 2 capture systems based on the carbonation/calcination loop have gained rapid interest due to promising carbonator CO 2 capture efficiency, low sorbent cost and no flue gases treatment is required before entering the system. These features together result in a competitively low cost CO 2 capture system. Among the key variables that influence the performance of these systems and their integration with power plants, the carbonation conversion of the sorbent and the heat requirement at calciner are the most relevant. Both variables are mainly influenced by CaO/CO 2 ratio and make-up flow of solids. New sorbents are under development to reduce the decay of their carbonation conversion with cycles. The aim of this study is to assess the competitiveness of new limestones with enhanced sorption behaviour applied to carbonation/calcination cycle integrated with a power plant, compared to raw limestone. The existence of an upper limit for the maximum average capture capacity of CaO has been considered. Above this limit, improving sorbent capture capacity does not lead to the corresponding increase in capture efficiency and, thus, reduction of CO 2 avoided cost is not observed. Simulations calculate the maximum price for enhanced sorbents to achieve a reduction in CO 2 removal cost under different process conditions (solid circulation and make-up flow). The present study may be used as an assessment tool of new sorbents to understand what prices would be competitive compare with raw limestone in the CO 2 looping capture systems. (author)

Neutralization of sulfuric acid solutions by calcite dissolution and the application to anoxic limestone drain design

International Nuclear Information System (INIS)

Huminicki, Danielle M.C.; Rimstidt, J. Donald

2008-01-01

Batch reactor (BR) experiments were conducted to measure the effect of hydrodynamics and gypsum coatings on calcite neutralization rates. A factorial array of BR experiments measured the H + concentration change by calcite dissolution over a pH range of 1.5-3.5 and Na 2 SO 4 concentrations of 0-1 M. The rate of H + concentration change with time was determined by numerical differentiation of H + concentration versus time. Regression modeling showed that for uncoated calcite, rates are only significantly affected by pH, r=-10 -2.32 a H + 0.76 . Whereas, for calcite coated with gypsum only time had a significant effect on calcite dissolution rates, r = -10 -1.96 t -0.53 . Because transport-limited dissolution rates for uncoated calcite are a function of the pH and Reynolds number, a model was developed to express the effects of these two variables on the rate of H + consumption for a solution with a Darcy velocity, q, through a porous medium with a particle radius, r p , such that r ' =1.08x10 -3 q 0.31 r p -0.69 m H + 0.87 . This equation was integrated via a numerical model to simulate the performance of an idealized anoxic limestone drain (ALD). This model predicts the pH and alkalinity change along the length of an ALD. The model shows that the efficiency of an ALD is greater when the Darcy velocity is low and the particle radius is small. In addition, the growth of gypsum coatings causes the rate of H + neutralization to decline as the square root of time as they form and block the H + transport to the calcite surface. Supersaturation with respect to gypsum, leading to coating formation, can be avoided by diluting the ALD feed solution or by replacing limestone with dolomite

Characterization of limestone of region South and Southeast of Para; Caracterizacao de calcario da regiao Sul e Sudeste do Para

Energy Technology Data Exchange (ETDEWEB)

Marinho, A.R.O.; Vieira, J.H.A.; Antunes Junior, L.V.; Medeiros, A.C.; Souza, G.P., E-mail: marabaonline@gmail.com [Universidade Federal do Sul e Sudeste do Para (FEMAT/UNIFESSPA), Maraba, PA (Brazil)

2014-07-01

Limestone is used in daily activities, and it is common the use of products containing calcium carbonate in various applications, from construction to food production, air purification to sewage treatment, the sugar refining materials for the toothpaste, the manufacture of glass and steel in the manufacture of paper, plastics, paints, ceramics and many others. The Limestone present in the region of south and southeast of Para is presented in deposits that have not been explored on a large scale, being justified a deepening in characteristics thereof. For the characterization of the material, gross samples were comminuted by crushing and ball mill, sieved and then separated into aliquots. In the end were used fluorescence analysis of X-ray, diffraction X-rays, determination of the moisture and loss on ignition of the material at 950 °C for one hour, obtaining results of a dolomitic limestone. (author)

Kinetics of the direct sulfation of limestone at the initial stage of crystal growth of the solid product

DEFF Research Database (Denmark)

Hu, Guilin; Dam-Johansen, Kim; Wedel, Stig

2011-01-01

The direct sulfation of limestone was studied in a quartz bench scale fixed‐bed reactor with the technique of data deconvolution. The obtained results show that the direct sulfation of limestone has a two‐period kinetic behavior: a short initial sulfation period with high but fast decreasing...... such as SO2, O2, and CO2 and the temperature. The sulfation process in the initial stage of the period with product crystal growth can be described by the combination of the sulfation reaction at the gas–solid interface, diffusion of the product ions toward the product crystal grains, diffusion of carbonate...

Accurate Prediction of Coronary Artery Disease Using Bioinformatics Algorithms

Directory of Open Access Journals (Sweden)

Hajar Shafiee

2016-06-01

Full Text Available Background and Objectives: Cardiovascular disease is one of the main causes of death in developed and Third World countries. According to the statement of the World Health Organization, it is predicted that death due to heart disease will rise to 23 million by 2030. According to the latest statistics reported by Iran’s Minister of health, 3.39% of all deaths are attributed to cardiovascular diseases and 19.5% are related to myocardial infarction. The aim of this study was to predict coronary artery disease using data mining algorithms. Methods: In this study, various bioinformatics algorithms, such as decision trees, neural networks, support vector machines, clustering, etc., were used to predict coronary heart disease. The data used in this study was taken from several valid databases (including 14 data. Results: In this research, data mining techniques can be effectively used to diagnose different diseases, including coronary artery disease. Also, for the first time, a prediction system based on support vector machine with the best possible accuracy was introduced. Conclusion: The results showed that among the features, thallium scan variable is the most important feature in the diagnosis of heart disease. Designation of machine prediction models, such as support vector machine learning algorithm can differentiate between sick and healthy individuals with 100% accuracy.

A Deep Learning Framework for Robust and Accurate Prediction of ncRNA-Protein Interactions Using Evolutionary Information.

Science.gov (United States)

Yi, Hai-Cheng; You, Zhu-Hong; Huang, De-Shuang; Li, Xiao; Jiang, Tong-Hai; Li, Li-Ping

2018-06-01

The interactions between non-coding RNAs (ncRNAs) and proteins play an important role in many biological processes, and their biological functions are primarily achieved by binding with a variety of proteins. High-throughput biological techniques are used to identify protein molecules bound with specific ncRNA, but they are usually expensive and time consuming. Deep learning provides a powerful solution to computationally predict RNA-protein interactions. In this work, we propose the RPI-SAN model by using the deep-learning stacked auto-encoder network to mine the hidden high-level features from RNA and protein sequences and feed them into a random forest (RF) model to predict ncRNA binding proteins. Stacked assembling is further used to improve the accuracy of the proposed method. Four benchmark datasets, including RPI2241, RPI488, RPI1807, and NPInter v2.0, were employed for the unbiased evaluation of five established prediction tools: RPI-Pred, IPMiner, RPISeq-RF, lncPro, and RPI-SAN. The experimental results show that our RPI-SAN model achieves much better performance than other methods, with accuracies of 90.77%, 89.7%, 96.1%, and 99.33%, respectively. It is anticipated that RPI-SAN can be used as an effective computational tool for future biomedical researches and can accurately predict the potential ncRNA-protein interacted pairs, which provides reliable guidance for biological research. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Removal of Iron and Manganese Using Cascade Aerator and Limestone Roughing Filter

Directory of Open Access Journals (Sweden)

Mohd Sanusi Azrin

2016-01-01

Full Text Available Combination between oxidation and filtration can be used for removing iron and manganese from groundwater especially when the concentrations of these metals were high. This study focused on the effectiveness of the cascade aerator and the size of the limestone filter media to remove iron and manganese from groundwater. Water samples used for this study were collected from orphanage home, Rumah Nur Kasih, Taiping. Universiti Sains Malaysia (USM has provided a tube well of 15 m depth and 150 mm diameter for the orphanage home. However, the water cannot be used for domestic consumption due to high amount of iron and manganese at 6.48 and 1.9 mg/L which exceeded the drinking water standard of 0.3 and 0.1 mg/L respectively. Using laboratory physical model, the study has shown that the removals of iron and manganese have reduce the concentration until 0.17 and 0.2 mg/L respectively. Thus, the results from this study which utilize cascade aerator and limestone roughing filter could be implemented on site for the community to use the ground water for domestic purposes.

Watershed area ratio accurately predicts daily streamflow in nested catchments in the Catskills, New York

Directory of Open Access Journals (Sweden)

Chris C. Gianfagna

2015-09-01

New hydrological insights for the region: Watershed area ratio was the most important basin parameter for estimating flow at upstream sites based on downstream flow. The area ratio alone explained 93% of the variance in the slopes of relationships between upstream and downstream flows. Regression analysis indicated that flow at any upstream point can be estimated by multiplying the flow at a downstream reference gage by the watershed area ratio. This method accurately predicted upstream flows at area ratios as low as 0.005. We also observed a very strong relationship (R2 = 0.79 between area ratio and flow–flow slopes in non-nested catchments. Our results indicate that a simple flow estimation method based on watershed area ratios is justifiable, and indeed preferred, for the estimation of daily streamflow in ungaged watersheds in the Catskills region.

Laboratory Investigations in Support of Dioxide-Limestone Sequestration in the Ocean

Energy Technology Data Exchange (ETDEWEB)

Dan Golomb; Eugene Barry; David Ryan; Stephen Pennell; Carl Lawton; Peter Swett; Devinder Arora; John Hannon; Michael Woods; Huishan Duan; Tom Lawlor

2008-09-30

Research under this Project has proven that liquid carbon dioxide can be emulsified in water by using very fine particles as emulsion stabilizers. Hydrophilic particles stabilize a CO{sub 2}-in-H{sub 2}O (C/W) emulsion; hydrophobic particles stabilize a H{sub 2}O-in-CO{sub 2} (W/C) emulsion. The C/W emulsion consists of tiny CO{sub 2} droplets coated with hydrophilic particles dispersed in water. The W/C emulsion consists of tiny H{sub 2}O droplets coated with hydrophobic particles dispersed in liquid carbon dioxide. The coated droplets are called globules. The emulsions could be used for deep ocean sequestration of CO{sub 2}. Liquid CO{sub 2} is sparsely soluble in water, and is less dense than seawater. If neat, liquid CO{sub 2} were injected in the deep ocean, it is likely that the dispersed CO{sub 2} droplets would buoy upward and flash into vapor before the droplets dissolve in seawater. The resulting vapor bubbles would re-emerge into the atmosphere. On the other hand, the emulsion is denser than seawater, hence the emulsion plume would sink toward greater depth from the injection point. For ocean sequestration a C/W emulsion appears to be most practical using limestone (CaCO{sub 3}) particles of a few to ten ?m diameter as stabilizing agents. A mix of one volume of liquid CO{sub 2} with two volumes of H{sub 2}O, plus 0.5 weight of pulverized limestone per weight of liquid CO{sub 2} forms a stable emulsion with density 1087 kg m{sup -3}. Ambient seawater at 500 m depth has a density of approximately 1026 kg m{sup -3}, so the emulsion plume would sink by gravity while entraining ambient seawater till density equilibrium is reached. Limestone is abundant world-wide, and is relatively cheap. Furthermore, upon disintegration of the emulsion the CaCO{sub 3} particles would partially buffer the carbonic acid that forms when CO{sub 2} dissolves in seawater, alleviating some of the concerns of discharging CO{sub 2} in the deep ocean. Laboratory experiments showed

Accurate and Reliable Prediction of the Binding Affinities of Macrocycles to Their Protein Targets.

Science.gov (United States)

Yu, Haoyu S; Deng, Yuqing; Wu, Yujie; Sindhikara, Dan; Rask, Amy R; Kimura, Takayuki; Abel, Robert; Wang, Lingle

2017-12-12

Macrocycles have been emerging as a very important drug class in the past few decades largely due to their expanded chemical diversity benefiting from advances in synthetic methods. Macrocyclization has been recognized as an effective way to restrict the conformational space of acyclic small molecule inhibitors with the hope of improving potency, selectivity, and metabolic stability. Because of their relatively larger size as compared to typical small molecule drugs and the complexity of the structures, efficient sampling of the accessible macrocycle conformational space and accurate prediction of their binding affinities to their target protein receptors poses a great challenge of central importance in computational macrocycle drug design. In this article, we present a novel method for relative binding free energy calculations between macrocycles with different ring sizes and between the macrocycles and their corresponding acyclic counterparts. We have applied the method to seven pharmaceutically interesting data sets taken from recent drug discovery projects including 33 macrocyclic ligands covering a diverse chemical space. The predicted binding free energies are in good agreement with experimental data with an overall root-mean-square error (RMSE) of 0.94 kcal/mol. This is to our knowledge the first time where the free energy of the macrocyclization of linear molecules has been directly calculated with rigorous physics-based free energy calculation methods, and we anticipate the outstanding accuracy demonstrated here across a broad range of target classes may have significant implications for macrocycle drug discovery.

Geophysical void detection at the site of an abandoned limestone quarry and underground mine in southwestern Pennsylvania

International Nuclear Information System (INIS)

Cohen, K.K.; Trevits, M.A.

1992-01-01

Locating underground voids, tunnels, and buried collapse structures continues to present a difficult problem for engineering geoscientists charged with this responsibility for a multitude of different studies. Solutions used and tested for void detection have run the gamut of surface geophysical and remote sensing techniques, to invasive trenching and drilling on closely-spaced centers. No where is the problem of locating underground voids more ubiquitous than in abandoned mined lands, and the U.S. Bureau of Mines continues to investigate this problem for areas overlying abandoned coal, metal, and nonmetal mines. Because of the great diversity of resources mined, the problem of void detection is compounded by the myriad of geologic conditions which exist for abandoned mined lands. At a control study site in southwestern Pennsylvania at the Bureau's Lake Lynn Laboratory, surface geophysical techniques, including seismic and other methods, were tested as a means to detect underground mine voids in the rather simple geologic environment of flat-lying sedimentary strata. The study site is underlain by an abandoned underground limestone mine developed in the Wymps Gap Limestone member of the Mississippian Mauch Chunk Formation. Portals or entrances into the mine, lead to drifts or tunnels driven into the limestone; these entries provided access to the limestone where it was extracted by the room-and-pillar method. The workings lie less than 300 ft from the surface, and survey lines or grids were positioned over the tunnels, the room-and-pillar zones, and the areas not mined. Results from these geophysical investigations are compared and contrasted. The application of this control study to abandoned mine void detection is apparent, but due to the carbonate terrain of the study site, the results may also have significance to sinkhole detection in karst topography

Combination of Slag, Limestone and Sedimentary Apatite in Columns for Phosphorus Removal from Sludge Fish Farm Effluents

Directory of Open Access Journals (Sweden)

Florent Chazarenc

2010-08-01

Full Text Available Laboratory scale studies have repeatedly reported high P-retention in slag, a by-product of the steel manufacturing industry. Thus, it has emerged as a potential material to increase P-removal from constructed wetlands (CWs. However, several limitations were highlighted by field experiments, including the high pH of treated water and clogging. We hypothesized that the addition of sedimentary rocks to slag would preserve P-removal properties while reducing the pH of treated water. Four 2.5 L-columns were filled with 100% apatite (column A; a 50% weight each mixture of limestone with apatite (column B; 10% steel slag located at the inlet, plus 45% limestone mixed with 45% apatite (column C; and a mixture of steel slag (10%, limestone (45% apatite (45% (column D. A synthetic effluent (26 mg P/L and a reconstituted sludge fish farm effluent containing 97 mg/L total suspended solids (TSS, 220 mg/L chemical oxygen demand (COD and 23.5 mg P/L phosphorus (P were applied sequentially during 373 and 176 days, under saturated flow conditions and 12–24 hours hydraulic residence time (HRT, respectively. Treatment performance, P-removal, pH and calcium (Ca2+ were monitored. Results indicated that columns that contained 10% weight steel slag resulted in a higher P retention capacity than the columns without steel slag. The highest P removal was achieved in column C, containing a layer of slag in the inlet zone, 45% apatite and 45% limestone. Feeding the columns with a reconstituted fish farm effluent led to biofilm development, but this had little effect on the P-removal. A combination of slag and sedimentary rocks represents a promising filtration material that could be useful downstream of CWs to further increase P-removal.

The stability of arsenic and selenium compounds that were retained in limestone in a coal gasification atmosphere

Energy Technology Data Exchange (ETDEWEB)

Diaz-Somoano, M.; Lopez-Anton, M.A.; Huggins, F.E.; Martinez-Tarazona, M.R. [CSIC, Oviedo (Spain)

2010-01-15

The aim of this work was to evaluate the stability of arsenic and selenium species retained in a lime/limestone mixture obtained by using limestone as a sorbent for gas cleaning in a coal gasification atmosphere. It was found that the stability of arsenic and selenium species produced by the gas-solid reactions with lime/limestone may be affected by their exposure to air and by their contact with water. The results confirm the conclusions of a previous work in which Ca(AsO{sub 2}){sub 2} and CaSe was postulated as the products of the reaction between the arsenic and selenium species present in a coal gasification atmosphere with lime/limestone. Moreover it was proved that the compounds (Ca(AsO{sub 2}){sub 2} and CaSe) may undergo transformations when the sorbents post-retention are stored or disposed of in air. From the results obtained by XAFS it was possible to identify the Ca{sub 3}(AsO{sub 4}){sub 2} produced by the oxidation of the Ca(ASO{sub 2}){sub 2} on the sorbent surface. The XAFS results for selenium showed that the CaSe formed on the sorbent was transformed to form several species, but mainly elemental Se. These changes in the speciation of arsenic and selenium may explain the behavior of the sorbent post-retention during the water solubility test. Although the selenium compounds and the products that may originate from their decomposition in water are not toxic, in the case of arsenic, species like Ca(AsO{sub 2}){sub 2} and Ca{sub 3}(AsO{sub 4}){sub 2} may lixiviate, and generate toxic arsenic compounds in solution that could pose a risk when the sorbent is finally disposed of.

Effect of limestone dust on vegetation in an area with a Mediterranean climate

Energy Technology Data Exchange (ETDEWEB)

Gale, J; Easton, J

1979-01-01

Possible effects of limestone dust on photosynthesis and transpiration throughout the summer season were assessed. Calculations were based on measurements of the dust accumulating on the leaves during the summer season, photosynthesis light curves of representative species, effect of dust on the optical characteristics of the leaves and stomatal diffusion resistances in the region of the quarry based on meteorological data. On a seasonal basis the dust was calculated to have only a very small effect in reducing photosynthesis and transpiration. A field experiment in which irrigated Xanthium strumarium plants were grown at different distances downwind from the quarry showed no deleterious effect of the dust even when plants close to the quarry were heavily coated. Comparison of aerial photographs taken just before the quarry was opened and 22 years later revealed no changes in the size, number or distribution pattern of the perennial, tree and shrub vegetation. It is concluded that, in an area with a Mediterranean climate, limestone dust, whilst being aesthetically offensive, does not significantly affect the growth of the natural vegetation. 13 references, 5 figures, 3 tables.

Towards more accurate and reliable predictions for nuclear applications

International Nuclear Information System (INIS)

Goriely, S.

2015-01-01

The need for nuclear data far from the valley of stability, for applications such as nuclear astrophysics or future nuclear facilities, challenges the robustness as well as the predictive power of present nuclear models. Most of the nuclear data evaluation and prediction are still performed on the basis of phenomenological nuclear models. For the last decades, important progress has been achieved in fundamental nuclear physics, making it now feasible to use more reliable, but also more complex microscopic or semi-microscopic models in the evaluation and prediction of nuclear data for practical applications. In the present contribution, the reliability and accuracy of recent nuclear theories are discussed for most of the relevant quantities needed to estimate reaction cross sections and beta-decay rates, namely nuclear masses, nuclear level densities, gamma-ray strength, fission properties and beta-strength functions. It is shown that nowadays, mean-field models can be tuned at the same level of accuracy as the phenomenological models, renormalized on experimental data if needed, and therefore can replace the phenomenogical inputs in the prediction of nuclear data. While fundamental nuclear physicists keep on improving state-of-the-art models, e.g. within the shell model or ab initio models, nuclear applications could make use of their most recent results as quantitative constraints or guides to improve the predictions in energy or mass domain that will remain inaccessible experimentally. (orig.)

Feedforward signal prediction for accurate motion systems using digital filters

NARCIS (Netherlands)

Butler, H.

2012-01-01

A positioning system that needs to accurately track a reference can benefit greatly from using feedforward. When using a force actuator, the feedforward needs to generate a force proportional to the reference acceleration, which can be measured by means of an accelerometer or can be created by

Evaluation of steel slag and crushed limestone mixtures as subbase material in flexible pavement

Directory of Open Access Journals (Sweden)

Ahmed Ebrahim Abu El-Maaty Behiry

2013-03-01

Full Text Available Steel slag is produced as a by-product during the oxidation of steel pellets in an electric arc furnace. This by-product that mainly consists of calcium carbonate is broken down to smaller sizes to be used as aggregates in pavement layers. They are particularly useful in areas where a good-quality aggregate is scarce. This research study was conducted to evaluate the effect of quantity of steel slag on the mechanical properties of blended mixes with crushed limestone aggregates, which used as subbase material in Egypt. Moreover, a theoretical analysis was employed to estimate the resistance for failure factors such as vertical deformations, vertical and radial stresses and vertical strains of subbase under overweight trucks loads. These loads cause severe deterioration to the pavement and thus reduce its life. The results indicated that the mechanical characteristics, and the resistance factors were improved by adding steel slag to the crushed limestone.

Extensive yellow crusts below limestone overhangs: a new taxon close to a minute epiphytic lichen

Czech Academy of Sciences Publication Activity Database

Vondrák, Jan; Moniri, M. H.; Malíček, Jiří; Košnar, J.

2017-01-01

Roč. 35, č. 3 (2017), s. 368-376 ISSN 0107-055X Institutional support: RVO:67985939 Keywords : Caloplaca substerilis * limestone rocks * Central Europe Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 0.847, year: 2016

Geological investigation of shaft mine in Devonian limestone in Kansas City, Missouri and other potentially dry excavated subsurface space in part of the Forest City Basin

Energy Technology Data Exchange (ETDEWEB)

Goebel, E.D.

1977-10-01

A high quality limestone is currently being mined from a deep shaft mine (1072 feet) in Middle Devonian rocks (Callaway) within the city limits of Kansas City, Missouri. About 15 acres of essentially dry space (room and pillar) with up to 14-foot ceilings have been developed. There are few natural joints observable in the rock within the mine. Some of these are periodically damp. More than 80% of the mine is dry. Saltwater from aquifers (Pennsylvanian) cut by the shaft accumulates behind the shaft at the pump station at 850 feet and at the bottom of the shaft (Devonian-Ordovician rocks). As long as the pumps lift the water to the surface, the mine can be kept relatively dry. Grouting of the aquifer's rocks in the shaft may seal off that source of water. The Burlington limestone of the Mississippian System is potentially mineable on the property now developed. The Burlington limestone, the Middle Devonian limestone, and the Kimmswick (Middle Ordovician) limestone are all potentially mineable by shaft mining in the northern part of Greater Kansas City and northward into the Forest City Basin.

Assessing the Effectiveness of Limestone from Oterkpolu Area in the Eastern region of Ghana as a Suitable Adsorbent for Water Defluoridation

International Nuclear Information System (INIS)

Droepenu, Eric Kwabena

2016-07-01

Fluoride-contamination of groundwater [above the World Health Organization (WHO) recommended limit of 1.5 mg/L] in the Upper East and Northern regions of Ghana is a well-known problem. Fluoride is, however, beneficial to humans if present in drinking water at levels between 0.7 – 1.5 mg/L. Although, there are some efficient methods for defluoridation of drinking water using various adsorbents, the magnitude of the problem has made it imperative to develop economically viable water defluoridation techniques using readily available natural resource as adsorbent. This will complement the existing defluoridation techniques in order to alleviate the difficulty faced by inhabitants of the affected communities. In addition, a method which is cost effective, easy to use by a layman, does not add other contaminants to water, and efficient in the long term is highly desirable. In this study, the effectiveness of readily available limestone from Oterkpolu (Yilo-Krobo district, Eastern region of Ghana) as fluoride adsorbent was assessed. A drinking water defluoridation technique was subsequently developed using the limestone with various grain sizes (i.e., 500 – 1000 μm, 1000 – 2000 μm and 2000 – 6350 μm) through Batch Adsorption Experiment (using NaF solution concentrations of 1, 5 and 10 mgF"-/L), followed by Column Adsorption Experiment using fluoride contaminated groundwater water samples from Bongo district. This was achieved through the geochemical and mineralogical characterization of Oterkpolu limestone using X-ray Powder Diffraction (XRD) and Petrographic Thin Section (PTS). In addition, the radiological risk associated with the use of the limestone for water defluoridation was assessed through the determination of the activity concentration of the Naturally-Occurring Radioactive Materials (NORMs) using a High-Purity Germanium (HPGe) γ-ray detector [γ-ray spectrometry], and computed Annual Effective Dose (AED). The study also evaluated the fluoride

Prediction of collision cross section and retention time for broad scope screening in gradient reversed-phase liquid chromatography-ion mobility-high resolution accurate mass spectrometry

DEFF Research Database (Denmark)

Mollerup, Christian Brinch; Mardal, Marie; Dalsgaard, Petur Weihe

2018-01-01

artificial neural networks (ANNs). Prediction was based on molecular descriptors, 827 RTs, and 357 CCS values from pharmaceuticals, drugs of abuse, and their metabolites. ANN models for the prediction of RT or CCS separately were examined, and the potential to predict both from a single model......Exact mass, retention time (RT), and collision cross section (CCS) are used as identification parameters in liquid chromatography coupled to ion mobility high resolution accurate mass spectrometry (LC-IM-HRMS). Targeted screening analyses are now more flexible and can be expanded for suspect...

230Th/234U dating of coral limestones and vertical uplift at Djibouti

International Nuclear Information System (INIS)

Faure, Hugues; Hoang, C.T.; Lalou, Claude

1980-01-01

Coral limestones sampled from marine terraces along the Afar coast have been dated by the 230 Th/ 234 U method. The ages confirm the stratigraphic unity of these formations and the existence of the paleo sea level dated 124 000 years ago in this region. These results permit to deduce the uplift rates of this littoral [fr

Use of limestone powder during incorporation of Pb-containing cathode ray tube waste in self-compacting concrete.

Science.gov (United States)

Sua-iam, Gritsada; Makul, Natt

2013-10-15

For several decades, cathode ray tubes (CRTs) were the primary display component of televisions and computers. The CRT glass envelope contains sufficient levels of lead oxide (PbO) to be considered hazardous, and there is a need for effective methods of permanently encapsulating this material during waste disposal. We examined the effect of adding limestone powder (LS) on the fresh and cured properties of self-compacting concrete (SCC) mixtures containing waste CRT glass. The SCC mixtures were prepared using Type 1 Portland cement at a constant cement content of 600 kg/m(3) and a water-to-cement ratio (w/c) of 0.38. CRT glass waste cullet was blended with river sand in proportions of 20 or 40% by weight. To suppress potential viscosity effects limestone powder was added at levels of 5, 10, or 15% by weight. The slump flow time, slump flow diameter, V-funnel flow time, Marsh cone flow time, and setting time of the fresh concrete were tested, as well as the compressive strength and ultrasonic pulse velocity of the hardened concrete. Addition of limestone powder improved the fresh and hardened properties. Pb leaching levels from the cured concrete were within US EPA allowable limits. Copyright © 2013 Elsevier Ltd. All rights reserved.

Accurate microRNA target prediction correlates with protein repression levels

Directory of Open Access Journals (Sweden)

Simossis Victor A

2009-09-01

Full Text Available Abstract Background MicroRNAs are small endogenously expressed non-coding RNA molecules that regulate target gene expression through translation repression or messenger RNA degradation. MicroRNA regulation is performed through pairing of the microRNA to sites in the messenger RNA of protein coding genes. Since experimental identification of miRNA target genes poses difficulties, computational microRNA target prediction is one of the key means in deciphering the role of microRNAs in development and disease. Results DIANA-microT 3.0 is an algorithm for microRNA target prediction which is based on several parameters calculated individually for each microRNA and combines conserved and non-conserved microRNA recognition elements into a final prediction score, which correlates with protein production fold change. Specifically, for each predicted interaction the program reports a signal to noise ratio and a precision score which can be used as an indication of the false positive rate of the prediction. Conclusion Recently, several computational target prediction programs were benchmarked based on a set of microRNA target genes identified by the pSILAC method. In this assessment DIANA-microT 3.0 was found to achieve the highest precision among the most widely used microRNA target prediction programs reaching approximately 66%. The DIANA-microT 3.0 prediction results are available online in a user friendly web server at http://www.microrna.gr/microT

Geostatistical three-dimensional modeling of oolite shoals, St. Louis Limestone, southwest Kansas

Science.gov (United States)

Qi, L.; Carr, T.R.; Goldstein, R.H.

2007-01-01

In the Hugoton embayment of southwestern Kansas, reservoirs composed of relatively thin (Big Bow and Sand Arroyo Creek fields. Lithofacies in uncored wells were predicted from digital logs using a neural network. The tilting effect from the Laramide orogeny was removed to construct restored structural surfaces at the time of deposition. Well data and structural maps were integrated to build 3-D models of oolitic reservoirs using stochastic simulations with geometry data. Three-dimensional models provide insights into the distribution, the external and internal geometry of oolitic deposits, and the sedimentologic processes that generated reservoir intervals. The structural highs and general structural trend had a significant impact on the distribution and orientation of the oolitic complexes. The depositional pattern and connectivity analysis suggest an overall aggradation of shallow-marine deposits during pulses of relative sea level rise followed by deepening near the top of the St. Louis Limestone. Cemented oolitic deposits were modeled as barriers and baffles and tend to concentrate at the edge of oolitic complexes. Spatial distribution of porous oolitic deposits controls the internal geometry of rock properties. Integrated geostatistical modeling methods can be applicable to other complex carbonate or siliciclastic reservoirs in shallow-marine settings. Copyright ?? 2007. The American Association of Petroleum Geologists. All rights reserved.

Large scale sodium interactions. Part 3. Chemical phenomena with limestone concrete

International Nuclear Information System (INIS)

Sallach, R.A.

1977-01-01

The description of the chemical processes and reaction products resulting from the exposure of concrete to molten sodium metal is important for a thorough, realistic assessment of the safety of CRBR-type reactors. Concretes are in general complex heterogenous substances whose ingredients can be derived from many sources. Consequently a wide variety of reaction processes and products might be anticipated. Initial attention has focused on a concrete in which both the aggregate and sandy components are derived from limestone. Presented are the chemical observations and experimental data from tests in which molten sodium metal at approximately 500 0 C is dropped into cold limestone concrete crucibles. Thermocouples immersed in the sodium pool indicate that the reaction proceeds in two stages. In the first stage which lasts 5 to 8 minutes, the temperature of the reacting mass hovers around 500 0 C. This stage is followed by a second stage of longer duration--greater than 100 minutes--where the temperature is 700 to 800 0 C. The main reaction product is a hard, fused, black slag which contains about 3/4 of the sodium in the initial charge. A secondary product is sodium oxide aerosol which accounts for the remaining 1/4 of the charge. It is significant that no free sodium metal is found in the slag; all sodium has completely reacted

Influence of limestone doses in the Manganese absorption by Brachiaria decumbens

International Nuclear Information System (INIS)

Armelin, Maria Jose A.; Fulas, Paulo M.M.; Saiki, Mitiko; Primavesi, Odo; Primavesi, Ana C.

2005-01-01

To restore a degraded pasture of Brachiaria decumbens, located in Sao Carlos - SP, Southeastern Brazil, under tropical climate, an experiment was carried out to study the influence of different methods of the limestone doses application on manganese absorption by the aboveground part of the forage, during 3 years of treatment. The experimental design was randomized block, with 6 replications and 8 treatments. The 100m 2 blocks were established in the pasture. Each block received a sequence of limestone doses (0, 1, 2, 4, and 8 t/ha) applied on soil surface with NK and, 2 t/ha applied on soil surface with plus one annual application of 1t/ha and NK, 4t/ha buried in the soil with NK, 4t/ha applied on soil surface without NK. Forages samples were collected 14 cm above soil surface. Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was the analytical method used to determine manganese content. The statistical analysis showed some significant variations of this element absorption by the plant with regard to the treatments, but anything that could compromise the mineral nutrition of forage. Moreover, the quality of forage for the animal feeding showed suitable agreement to manganese requirement. INAA showed that it can be an alternative option for agronomical researches that require the knowledge of the manganese concentration. (author)

Improvement of a land surface model for accurate prediction of surface energy and water balances

International Nuclear Information System (INIS)

Katata, Genki

2009-02-01

In order to predict energy and water balances between the biosphere and atmosphere accurately, sophisticated schemes to calculate evaporation and adsorption processes in the soil and cloud (fog) water deposition on vegetation were implemented in the one-dimensional atmosphere-soil-vegetation model including CO 2 exchange process (SOLVEG2). Performance tests in arid areas showed that the above schemes have a significant effect on surface energy and water balances. The framework of the above schemes incorporated in the SOLVEG2 and instruction for running the model are documented. With further modifications of the model to implement the carbon exchanges between the vegetation and soil, deposition processes of materials on the land surface, vegetation stress-growth-dynamics etc., the model is suited to evaluate an effect of environmental loads to ecosystems by atmospheric pollutants and radioactive substances under climate changes such as global warming and drought. (author)

Performance Monitoring: Evaluating an Organic Carbon-Limestone PRB for Treatment of Heavy Metals and Acidity

Science.gov (United States)

Since 2004, researchers from the U.S. EPA National Risk Management Research Laboratory (NRMRL) have annually evaluated performance of an organic carbon-limestone permeable reactive barrier (PRB) system installed in 2003 by EPA Region 6 at the Delatte Metals Superfund site in Ponc...

A hybrid treatment of ozonation with limestone adsorption processes for the removal of Fe2+ in groundwater: Fixed bed column study

Science.gov (United States)

Akbar, Nor Azliza; Aziz, Hamidi Abdul; Adlan, Mohd Nordin

2017-10-01

During pumping of groundwater to the surface, the reaction between dissolved iron (Fe2+) and oxygen causes oxidation to ferric iron (Fe3+), thereby increasing the concentration of Fe2+. In this research, the potential application of ozonation with limestone adsorption to remove Fe2+ from groundwater was investigated through batch ozonation and fixed-bed-column studies. Groundwater samples were collected from a University Science Malaysia tube well (initial concentration of Fe2+, Co=1.563 mg/L). The effect of varying ozone dosages (10, 12.5, 15, 17.5, 20, 22.5, and 25 g/Nm3) was analyzed to determine the optimum ozone dosage for treatment. The characteristics of the column data and breakthrough curve were analyzed and predicted using mathematical models, such as Adam Bohart, Thomas, and Yoon-Nelson models. The data fitted well to the Thomas and Yoon-Nelson models, with correlation coefficient r2>0.93, but not to the Adam Bohart (r2=0.47). The total Fe2+ removed was 72% (final concentration of Fe2+, Ct=0.426 mg/L) at the maximum dosage of 25 g/Nm3 through ozonation only. However, the efficiency of Fe2+ removal was increased up to 99.5% (Ct=0.008 mg/L) when the hybrid treatment of ozonation with limestone adsorption was applied in this study. Thus, this integrated treatment was considerably more effective in removing Fe2+ than single ozonation treatment.

Physiological and behavioral response of stonefly nymphs to enhanced limestone treatment of acid mine drainage

Energy Technology Data Exchange (ETDEWEB)

Cole, M.B.; Arnold, D.E.; Watten, B.J. [ABR Inc., PO Box 249, OR (USA). Environmental Research and Services

2001-07-01

A new acid mine drainage (AMD) treatment system uses pulsed, fluidized beds of limestone, and carbon dioxide pretreatment of influent AMD to enhance limestone neutralization of AMD. Laboratory studies were carried out to evaluate the behavior and physiology of larval stoneflies (Pteronarcys proteus, Plecoptera) exposed to effluents produced by the treatment system. Survival, sodium balance, drift, and feeding responses by P. proteus to treated and untreated AMD were examined. P. proteus nymphs exhibited significant losses of whole body sodium in exposures to untreated AMD. Nymphs exposed to treated effluents experienced no loss of whole-body sodium. No significant differences in feeding or drift behavior occurred between nymphs exposed to treated effluents and those exposed to AMD-free controls. The treatment system, with and without CO{sub 2} pretreatment, provided water that was not toxic to the test animals, and that allowed normal behavioral and physiological function.

Composição e solubilidade in vitro de calcários calcíticos de Minas Gerais Composition and in vitro solubility of Minas Gerais limestones

Directory of Open Access Journals (Sweden)

Édison José Fassani

2004-08-01

Full Text Available O experimento foi conduzido no Laboratório de Pesquisa Animal do Departamento de Zootecnia da Universidade Federal de Lavras - UFLA, em Lavras - MG, Brasil, com objetivo de avaliar as características físico-químicas de calcários calcíticos utilizados na alimentação de poedeiras. Foi utilizado um delineamento inteiramente casualizado, em esquema fatorial 4x5, sendo 4 calcários calcíticos extraídos em diferentes regiões de Minas Gerais (Ijaci, Barroso, Iguatama e Formiga em 5 granulometrias padronizadas (0,15-0,30; 0,30-0,60; 0,60-1,20; 1,20-2,00 e 2,00-4,00 mm, totalizando 20 tratamentos, com 8 repetições. Os calcários foram encaminhados ao laboratório, onde se determinaram a composição mineral e a solubilidade in vitro determinada pelo método da perda de peso. Pela análise mineral dos calcários inferiram-se algumas diferenças numéricas, principalmente em elementos como ferro e manganês, além de detectar a presença de zinco e cobre em menor quantidade. Houve interação (PThe experiment was carried out at the Animal Research Laboratory the Department of Animal Science of the Federal University of Lavras - UFLA, in Lavras - MG, Brazil, with objective of evaluating the physical-chemistries characteristics of limestones used in the laying hens feeding. The experimental design was completely randomized in a 4x5 factorial arrangement, being four limestones extracted in different areas of Minas Gerais (Ijaci, Barroso, Iguatama and Formiga in five particle size standardized (0.15-0.30, 0.30-0.60, 0.60-1.20, 1.20-2.00 and 2.00-4.00 mm, amounting twenty treatments, with eight replications. The limestones were directed to the laboratory where was determined the mineral composition and the in vitro solubility, certain for the method of the weight loss. The mineral analysis of the limestones, indicated some numerical differences mainly in elements as iron and manganese, besides detecting the presence of zinc and copper in smaller

Integrating metabolic performance, thermal tolerance, and plasticity enables for more accurate predictions on species vulnerability to acute and chronic effects of global warming.

Science.gov (United States)

Magozzi, Sarah; Calosi, Piero

2015-01-01

Predicting species vulnerability to global warming requires a comprehensive, mechanistic understanding of sublethal and lethal thermal tolerances. To date, however, most studies investigating species physiological responses to increasing temperature have focused on the underlying physiological traits of either acute or chronic tolerance in isolation. Here we propose an integrative, synthetic approach including the investigation of multiple physiological traits (metabolic performance and thermal tolerance), and their plasticity, to provide more accurate and balanced predictions on species and assemblage vulnerability to both acute and chronic effects of global warming. We applied this approach to more accurately elucidate relative species vulnerability to warming within an assemblage of six caridean prawns occurring in the same geographic, hence macroclimatic, region, but living in different thermal habitats. Prawns were exposed to four incubation temperatures (10, 15, 20 and 25 °C) for 7 days, their metabolic rates and upper thermal limits were measured, and plasticity was calculated according to the concept of Reaction Norms, as well as Q10 for metabolism. Compared to species occupying narrower/more stable thermal niches, species inhabiting broader/more variable thermal environments (including the invasive Palaemon macrodactylus) are likely to be less vulnerable to extreme acute thermal events as a result of their higher upper thermal limits. Nevertheless, they may be at greater risk from chronic exposure to warming due to the greater metabolic costs they incur. Indeed, a trade-off between acute and chronic tolerance was apparent in the assemblage investigated. However, the invasive species P. macrodactylus represents an exception to this pattern, showing elevated thermal limits and plasticity of these limits, as well as a high metabolic control. In general, integrating multiple proxies for species physiological acute and chronic responses to increasing

Can radiation therapy treatment planning system accurately predict surface doses in postmastectomy radiation therapy patients?

International Nuclear Information System (INIS)

Wong, Sharon; Back, Michael; Tan, Poh Wee; Lee, Khai Mun; Baggarley, Shaun; Lu, Jaide Jay

2012-01-01

Skin doses have been an important factor in the dose prescription for breast radiotherapy. Recent advances in radiotherapy treatment techniques, such as intensity-modulated radiation therapy (IMRT) and new treatment schemes such as hypofractionated breast therapy have made the precise determination of the surface dose necessary. Detailed information of the dose at various depths of the skin is also critical in designing new treatment strategies. The purpose of this work was to assess the accuracy of surface dose calculation by a clinically used treatment planning system and those measured by thermoluminescence dosimeters (TLDs) in a customized chest wall phantom. This study involved the construction of a chest wall phantom for skin dose assessment. Seven TLDs were distributed throughout each right chest wall phantom to give adequate representation of measured radiation doses. Point doses from the CMS Xio® treatment planning system (TPS) were calculated for each relevant TLD positions and results correlated. There were no significant difference between measured absorbed dose by TLD and calculated doses by the TPS (p > 0.05 (1-tailed). Dose accuracy of up to 2.21% was found. The deviations from the calculated absorbed doses were overall larger (3.4%) when wedges and bolus were used. 3D radiotherapy TPS is a useful and accurate tool to assess the accuracy of surface dose. Our studies have shown that radiation treatment accuracy expressed as a comparison between calculated doses (by TPS) and measured doses (by TLD dosimetry) can be accurately predicted for tangential treatment of the chest wall after mastectomy.

Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications

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Galdenzi Sandro

2012-07-01

Full Text Available The measurement of the weight loss in limestone tablets placed in the Grotta del Fiume (Frasassi, Italy provided data on the rate of limestone dissolution due to the sulfidic water and on the influence of local environmental conditions.A linear average corrosion rate of 24 mm ka-1 was measured in stagnant water, while the values were higher (68-119 mm ka-1 where the hydrologic conditions facilitate water movement and gas exchanges. In these zones the increase in water aggressivity is due to mixing with descending, O2-rich, seepage water and is also favored by easier gas exchange between ground-water and the cave atmosphere. Very intense corrosion was due to weakly turbulent flow, which caused evident changes in the tablets shape in few months. A comparison between the measured corrosion rates and the cave features showed that the values measured in the pools with stagnant water are too low to account for the largest solutional cave development, while the average values measured in the zones with moving water are compatible with the dimension of the cave rooms in the main cave levels, that must have developed when the base level was stable and hydrologic conditions favored the increase of water aggressivity.

Determination of calcium and iron in limestone by X-ray fluorescence method

International Nuclear Information System (INIS)

Sovtsova, M.K.

1977-01-01

The results of determining calcium and iron content in limestone by X-ray fluorescence method are described. The 109 Cd isotape was chosen as a source for excitation, as it permited to reduce the concentration degeneration in the range of large Ca contents due to the larger energy of the primary radiation. The root-mean-square deviation from the data of chemical analysis was +-0.02%FeO and +-0.22%CaO

Importance of granulometry on phase evolution and phase-to-phase relationships of experimentally burned impure limestones intended for production of hydraulic lime and/or natural cement

Science.gov (United States)

Kozlovcev, Petr; Přikryl, Richard; Přikrylová, Jiřina

2015-04-01

In contrast to modern ordinary Portland cement production from finely ground raw material blends, ancient burning of hydraulic lime was conducted by burning larger pieces of natural raw material. Due to natural variability of raw material composition, exploitation of different beds from even one formation can result the product with significantly different composition and/or properties. Prague basin (Neoproterozoic to pre-Variscan Palaeozoic of the central part of the Bohemian Massif - the so-called Barrandian area, Czech Republic) represents a classical example of the limestone-rich region with long-term history of limestone burning for quick lime and/or various types of hydraulic binders. Due to the fact that burning of natural hydraulic lime has been abandoned in this region at the turn of 19th/20th c., significant gap in knowledge on the behavior of various limestone types and on the influence of minor variance in composition on the quality of burned product is encountered. Moreover, the importance of employment of larger pieces of raw material for burning for the development of proper phase-to-phase relationships (i.e. development of hydraulic phases below sintering temperature at mutual contacts of minerals) has not been examined before. To fill this gap, a representative specimens of major limestone types from the Prague basin have been selected for experimental study: Upper Silurian limestone types (Přídolí and Kopanina Lms.), and Lower Devonian limestones (Radotín, Kotýs, Řeporyje, Dvorce-Prokop, and Zlíchov Lms.). Petrographic character of the experimental material was examined by polarizing microscopy, cathodoluminescence, scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS), and X-ray diffraction (XRD) of insoluble residue. Based on the data from wet silicate analyses, modal composition of studied impure limestones was computed. Experimental raw material was burned in laboratory electric furnace at 1000 and 1200°C for 3

Accurate Predictions of Mean Geomagnetic Dipole Excursion and Reversal Frequencies, Mean Paleomagnetic Field Intensity, and the Radius of Earth's Core Using McLeod's Rule

Science.gov (United States)

Voorhies, Coerte V.; Conrad, Joy

1996-01-01

The geomagnetic spatial power spectrum R(sub n)(r) is the mean square magnetic induction represented by degree n spherical harmonic coefficients of the internal scalar potential averaged over the geocentric sphere of radius r. McLeod's Rule for the magnetic field generated by Earth's core geodynamo says that the expected core surface power spectrum (R(sub nc)(c)) is inversely proportional to (2n + 1) for 1 less than n less than or equal to N(sub E). McLeod's Rule is verified by locating Earth's core with main field models of Magsat data; the estimated core radius of 3485 kn is close to the seismologic value for c of 3480 km. McLeod's Rule and similar forms are then calibrated with the model values of R(sub n) for 3 less than or = n less than or = 12. Extrapolation to the degree 1 dipole predicts the expectation value of Earth's dipole moment to be about 5.89 x 10(exp 22) Am(exp 2)rms (74.5% of the 1980 value) and the expected geomagnetic intensity to be about 35.6 (mu)T rms at Earth's surface. Archeo- and paleomagnetic field intensity data show these and related predictions to be reasonably accurate. The probability distribution chi(exp 2) with 2n+1 degrees of freedom is assigned to (2n + 1)R(sub nc)/(R(sub nc). Extending this to the dipole implies that an exceptionally weak absolute dipole moment (less than or = 20% of the 1980 value) will exist during 2.5% of geologic time. The mean duration for such major geomagnetic dipole power excursions, one quarter of which feature durable axial dipole reversal, is estimated from the modern dipole power time-scale and the statistical model of excursions. The resulting mean excursion duration of 2767 years forces us to predict an average of 9.04 excursions per million years, 2.26 axial dipole reversals per million years, and a mean reversal duration of 5533 years. Paleomagnetic data show these predictions to be quite accurate. McLeod's Rule led to accurate predictions of Earth's core radius, mean paleomagnetic field

COPROLITES FROM THE DANIAN LIMESTONE (LOWER PALEOCENE) OF FAXE QUARRY, DENMARK

DEFF Research Database (Denmark)

Milàn, Jesper

2010-01-01

are attributed to sharks, and large, cylindrical coprolites with longitudinal striations on the surface are identified as crocodile coprolites. Fish and sharks are known from abundant finds of otoliths and teeth in Faxe Quarry, and crocodiles are known from finds of single bones and teeth.......A collection of coprolites found in the Danian (Lower Paleocene) limestone of Faxe Quarry, Denmark, is described and attributed to the respective producers. Small, drop-like specimens with weak signs of spiral coiling are attributed to fish. Larger, heteropolar, spirally-coiled specimens...

Petrographic Evidence of Microbial Mats in the Upper Cretaceous Fish-Bearing, Organic-Rich Limestone, Agua Nueva Formation, Central Mexico

Science.gov (United States)

Blanco, A.; Maurrasse, F. J.; Hernández-Ávila, J.; Ángeles-Trigueros, S. A.; García-Cabrera, M. E.

2013-05-01

We document petrographic evidence of microbial mats in the Upper Cretaceous Agua Nueva Formation in the area of Xilitla (San Luis Potosí, Central Mexico), located in the southern part of the Tampico-Misantla basin. The sequence consists predominantly of alternating decimeter-thick beds of fossiliferous dark laminated limestone (C-org > 1.0wt%), and light gray, bioturbated limestone (C-org Duque-Botero and Maurrasse, 2005; 2008). These structures are also analogous to microbial mats in present environments, and Devonian deposits (Kremer, 2006). In addition, the laminae at Xilitla include filamentous bacterial structures, as thin and segmented red elements. In some thin sections, filaments appear to be embedded within the crinkly laminae and shreds showing the same pattern of folding, suggestive of biomorphic elements that represent the main producers of the organic matter associated with the laminae. Thus, exceptional bacterial activity characterizes sedimentation during the accumulation of the Agua Nueva Formation. Oxygen-deficient conditions related to the microbial mats were an important element in the mass mortality and preservation of the fish assemblages. Absence of bioturbation, pervasive framboidal pyrite, and the high concentration of organic matter (TOC ranges from 1.2% to 8wt%) in the dark limestones are consistent with persistent recurring dysoxic/anoxic conditions, and the light-gray bioturbated limestones represent relatively well-oxygenated episodes. Planktonic foraminifera (Rotalipora cushmani) and Inoceramu labiatus indicate a time interval from the latest Cenomanian through the earliest Turonian, thus this long interval of severe oxygen deficiency is coeval with Oceanic Anoxic Event 2 (OAE-2). [Duque-Botero and Maurrasse. 2005. Jour. Iberian Geology (31), 85-98; 2008. Cret. Res., 29, 957-964; Kremer. 2006. Acta Palaeontologica Polonica (51, 1), 143-154

Diet of the Assamese macaque Macaca assamensis in lime-stone habitats of Nonggang, China

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Qihai ZHOU, Hua WEI, Zhonghao HUANG, Chengming HUANG

2011-02-01

Full Text Available To enhance our understanding of dietary adaptations in macaques we studied the diet of the Assamese macaque Macaca assamensis in limestone seasonal rain forests at Nonggang Nature Reserve, China from September 2005 to August 2006. Our results show that although macaques fed on many plant species, 85.2% of the diet came from only 12 species, of which a bamboo species, Indocalamus calcicolus contributed to 62% of the diet. Young leaves were staple food items (74.1% of the diet for Assamese macaques at Nonggang, and constituted the bulk of monthly diets almost year-round, ranging from 44.9% (July to 92.9% (May. Young parts of Indocalamus calcicolus unexpanded leaves contributed to a large proportion of the young leaf diet in most months. Fruit accounted for only 17.4% of the diet, with a peak of consumption in July. We suggest that this highly folivorous diet may be related to the long lean season of fruit availability in limestone habitats as well as the utilization of cliffs of low fruit availability [Current Zoology 57 (1: 18–25, 2011].

EFFECTS OF LIMESTONE PARTICLE SIZE ON PERFORMANCE AND SHELL QUALITY OF JAPANESE QUAILS GRANULOMETRIA DO CALCÁRIO NO DESEMPENHO E QUALIDADE DA CASCA DE OVOS DE CODORNAS JAPONESAS

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Marcos Barcellos Café

2006-12-01

Full Text Available This experiment evaluated limestone particle size of diet on performance and shell quality of japanese quails. The experimental design used was completely randomized with five treatments (five different particle sizes of limestone and five replicates of 16 birds each in a total of 400 birds. The treatments were: T1 – Diets with 100% of the limestone coarse; T2 – diets with 70% of limestone coarse and 30% fine; T3 – diets with 30% of limestone coarse and 70% fine; T4 - Diets with 100% of the limestone fine and T5 – Diets with 100% of medium limestone. The experimental diets were formulated to meet NRC (1994 nutritional requirements. The treatment of 100% fine particle size improved egg production and bird performance compared to the treatment with 100% medium particle size. There was no effect of limestone particle size on shell quality of quail eggs. The fine or coarse limestone particle size can be used in diets of laying quails. The medium limestone particle size is not recommended on laying Japanese quail diets. KEY WORDS: Limestone, particle size, japonese quails, egg production, shell egg quality. O objetivo do presente estudo foi avaliar o efeito da granulometria do calcário calcítico da ração de postura sobre o desempenho produtivo e a qualidade da casca dos ovos de codornas japonesas (Coturnix coturnix. O delineamento experimental adotado foi o inteiramente ao acaso com cinco tratamentos, com cinco repetições de 16 aves cada, num total de quatrocentas aves. Os tratamentos foram: T1 – ração com 100% de calcário de granulometria grossa; T2 – ração com 70% de calcário de granulometria grossa e 30% fina; T3 – ração com 30% de calcário de granulometria grossa e 70% fina; T4 – ração com 100% de calcário de granulometria fina; T5 – ração com 100% de calcário de granulometria média. As rações experimentais eram isonutritivas e foram formuladas para conter os níveis nutricionais sugeridos pelo NRC (1994

A simple, fast, and accurate thermodynamic-based approach for transfer and prediction of gas chromatography retention times between columns and instruments Part III: Retention time prediction on target column.

Science.gov (United States)

Hou, Siyuan; Stevenson, Keisean A J M; Harynuk, James J

2018-03-27

This is the third part of a three-part series of papers. In Part I, we presented a method for determining the actual effective geometry of a reference column as well as the thermodynamic-based parameters of a set of probe compounds in an in-house mixture. Part II introduced an approach for estimating the actual effective geometry of a target column by collecting retention data of the same mixture of probe compounds on the target column and using their thermodynamic parameters, acquired on the reference column, as a bridge between both systems. Part III, presented here, demonstrates the retention time transfer and prediction from the reference column to the target column using experimental data for a separate mixture of compounds. To predict the retention time of a new compound, we first estimate its thermodynamic-based parameters on the reference column (using geometric parameters determined previously). The compound's retention time on a second column (of previously determined geometry) is then predicted. The models and the associated optimization algorithms were tested using simulated and experimental data. The accuracy of predicted retention times shows that the proposed approach is simple, fast, and accurate for retention time transfer and prediction between gas chromatography columns. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water flow in the Oxfordian and Dogger limestone around the Meuse/Haute-Marne underground research laboratory

International Nuclear Information System (INIS)

Linard, Y.; Vinsot, A.; Delay, J.; Scholz, E.; Lundy, M.; Garry, B.; La Vaissiere, R. de; Cruchaudet, M.; Dewonck, S.; Vigneron, G.; Vincent, B.; Wechner, S.

2010-01-01

Document available in extended abstract form only. Within its scientific program to study the feasibility of a high level radioactive waste disposal in the Callovo-Oxfordian argillaceous rock (COx) of the eastern Paris Basin, Andra has conducted an extensive characterization of the Oxfordian and Dogger limestone formations above and below the COx. More than 35 wells ranging from 400 to 700 meters deep were drilled over 15 years to study a 400 km 2 area around the Andra's Meuse / Haute-Marne Underground Research Laboratory (URL). An original methodology was applied in these wells to characterize the geology, the hydrogeology and the geochemistry of the Jurassic carbonates. This multidisciplinary effort provided a unique set of 3D data. The first purpose of this study is to integrate the geological, hydrogeological and geochemical data into a water flow conceptual model. Geological data include the study of cored wells, complete modern wire-line log sets in both cored and un-cored wells, and outcrop analogues. Hydrogeological data include transmissivity and hydraulic head measurements in the Oxfordian and Dogger limestone formations. Geochemical data include several on site measurements (pH, alkalinity, electrical conductivity, temperature) and chemical and isotopic analyses performed on water samples taken at selected depths. More than one hundred hydraulic tests have been performed since 1994 to measure transmissivity distribution in the Oxfordian and Dogger limestone. Several hydraulic testing methods were used in each well: global pumping tests, fluid logging tests, thermal flow logging tests and packer tests. After completion of the hydraulic tests, hydraulic heads were deduced from long term pressure measurements in open wells or in multi-packer completions; pressure monitoring lasted between a few months and more than 10 years. Long term/high volume pumping tests were also performed after the hydraulic tests to obtain a stationary composition of the well

Stratigraphic variations and secondary porosity within the Maynardville Limestone in Bear Creek Valley, Y-12 Plant, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Goldstrand, P.M.

1995-05-01

To evaluate groundwater and surface water contamination and migration near the Oak Ridge Y-12 plant, a Comprehensive Groundwater Monitoring Plan was developed. As part of the Maynardville exit pathways monitoring program, monitoring well clusters were ii installed perpendicular to the strike of the Maynardville Limestone, that underlies the southern part of the Y-12 Plant and Bear Creek Valley (BCV). The Maynardville Project is designed to locate potential exit pathways of groundwater, study geochemical characteristics and factors affecting the occurrence and distribution of water-bearing intervals, and provide hydrogeologic information to be used to reduce the potential impacts of contaminants entering the Maynardville Limestone

Unilateral Prostate Cancer Cannot be Accurately Predicted in Low-Risk Patients

International Nuclear Information System (INIS)

Isbarn, Hendrik; Karakiewicz, Pierre I.; Vogel, Susanne

2010-01-01

Purpose: Hemiablative therapy (HAT) is increasing in popularity for treatment of patients with low-risk prostate cancer (PCa). The validity of this therapeutic modality, which exclusively treats PCa within a single prostate lobe, rests on accurate staging. We tested the accuracy of unilaterally unremarkable biopsy findings in cases of low-risk PCa patients who are potential candidates for HAT. Methods and Materials: The study population consisted of 243 men with clinical stage ≤T2a, a prostate-specific antigen (PSA) concentration of <10 ng/ml, a biopsy-proven Gleason sum of ≤6, and a maximum of 2 ipsilateral positive biopsy results out of 10 or more cores. All men underwent a radical prostatectomy, and pathology stage was used as the gold standard. Univariable and multivariable logistic regression models were tested for significant predictors of unilateral, organ-confined PCa. These predictors consisted of PSA, %fPSA (defined as the quotient of free [uncomplexed] PSA divided by the total PSA), clinical stage (T2a vs. T1c), gland volume, and number of positive biopsy cores (2 vs. 1). Results: Despite unilateral stage at biopsy, bilateral or even non-organ-confined PCa was reported in 64% of all patients. In multivariable analyses, no variable could clearly and independently predict the presence of unilateral PCa. This was reflected in an overall accuracy of 58% (95% confidence interval, 50.6-65.8%). Conclusions: Two-thirds of patients with unilateral low-risk PCa, confirmed by clinical stage and biopsy findings, have bilateral or non-organ-confined PCa at radical prostatectomy. This alarming finding questions the safety and validity of HAT.

Bedrock stability in southeastern Sweden. Evidence from fracturing in the ordovician limestones of northern Oeland

International Nuclear Information System (INIS)

Milnes, A.G.; Gee, D.G.

1992-09-01

The stability of the bedrock in SE Sweden with regard to radioactive waste disposal has recently been the subject of some controversy. In order to better assess the age and significance of fracturing in the Precambrian basement at the site of the Aespoe Hard Rock Laboratory (HRL), near Oskarshamn, a detailed analysis of fracturing in the lower Ordovician limestones exposed along the west coast of the neighbouring island of Oeland has been carried out. The limestones form continuously exposed shore platforms, in segments up to 30 m broad and several kilometres long. These, and numerous quarries, provide ideal objects for quantitative analysis (ground and air photo mapping, scanline logging), and unique opportunities for investigating the amount of movement on the fractures, because of well-developed bedding and abundant rod-shaped fossils on the bedding surfaces. The fracture patterns are dominated by two sets of subvertical fractures, a NW trending closely spaced and strongly orientated set and a NNE-ENE trending widely spaced and variably orientated set. Only about 10% of the fractures in both sets show lateral fossil displacement, with maximum movement of 5 cm, and only 3% of the fractures show vertical displacement of bedding (maximum 8 cm). All in all, the lower Ordovician limestones along the exposed shoreline have suffered remarkably little deformation since deposition, i.e. over the last 500 million years. Appreciable bedrock instability, if it occurred, must have been concentrated offshore, or in the unexposed segments of the coastline, where some weak indications of slight movement (changes of a few metres in stratigraphic level) have been observed. Among other recommendations for further work, geophysical investigations to test these indications are suggested. (54 refs.)

Accurate prediction of stability changes in protein mutants by combining machine learning with structure based computational mutagenesis.

Science.gov (United States)

Masso, Majid; Vaisman, Iosif I

2008-09-15

Accurate predictive models for the impact of single amino acid substitutions on protein stability provide insight into protein structure and function. Such models are also valuable for the design and engineering of new proteins. Previously described methods have utilized properties of protein sequence or structure to predict the free energy change of mutants due to thermal (DeltaDeltaG) and denaturant (DeltaDeltaG(H2O)) denaturations, as well as mutant thermal stability (DeltaT(m)), through the application of either computational energy-based approaches or machine learning techniques. However, accuracy associated with applying these methods separately is frequently far from optimal. We detail a computational mutagenesis technique based on a four-body, knowledge-based, statistical contact potential. For any mutation due to a single amino acid replacement in a protein, the method provides an empirical normalized measure of the ensuing environmental perturbation occurring at every residue position. A feature vector is generated for the mutant by considering perturbations at the mutated position and it's ordered six nearest neighbors in the 3-dimensional (3D) protein structure. These predictors of stability change are evaluated by applying machine learning tools to large training sets of mutants derived from diverse proteins that have been experimentally studied and described. Predictive models based on our combined approach are either comparable to, or in many cases significantly outperform, previously published results. A web server with supporting documentation is available at http://proteins.gmu.edu/automute.

Predicting mercury retention in utility gas cleaning systems with SCR/ESP/FGD combinations or activated carbon injection

Energy Technology Data Exchange (ETDEWEB)

Krishnakumar, Balaji; Naik, Chitralkumar V.; Niksa, Stephen [Niksa Energy Associates LLC, Belmont, CA (United States); Fujiwara, Naoki [Idemitsu Kosan Co., Ltd, Chiba (Japan). Coal and Environment Research Lab.

2013-07-01

This paper presents validations of the Hg speciation predicted by NEA's MercuRator trademark package with an American field test database for 28 full-scale utility gas cleaning systems. It emphasizes SCR/ESP/FGD combinations and activated carbon injection because these two applications present the best long- term prospects for Hg control by coal-burning utilities. Validations of the extents of Hg{sup 0} oxidation across SCRs and of Hg retention in wet FGDs gave correlation coefficients greater than 0.9 for both units. A transport-based FGD analysis correctly assessed the potential for Hg{sup 0} re-emission in one limestone wet FGD. Among the ten stations in the SCR/ESP/FGD validations, the simulations correctly identified 3 of 4 of the relatively high Hg emissions rates; all four of the sites with moderate emissions rates; and both sites with the lowest emission rates. The validations for ACI applications demonstrated that Hg removals can be accurately estimated for the full domain of coal quality, LOI, and ACI rates for both untreated and brominated carbon sorbents. The predictions for ACI depict the test-to-test variations in most cases, and accurately describe the impact of ACI configuration and sorbent type. ACI into FFs is the most effective configuration, although ACI into ESPs often removes 90% or more Hg, provided that there is sufficient residence time and Cl in the flue gas. Brominated sorbents perform better than untreated carbons, unless SO{sub 3} condensation inhibits Hg adsorption.

Combining Mean and Standard Deviation of Hounsfield Unit Measurements from Preoperative CT Allows More Accurate Prediction of Urinary Stone Composition Than Mean Hounsfield Units Alone.

Science.gov (United States)

Tailly, Thomas; Larish, Yaniv; Nadeau, Brandon; Violette, Philippe; Glickman, Leonard; Olvera-Posada, Daniel; Alenezi, Husain; Amann, Justin; Denstedt, John; Razvi, Hassan

2016-04-01

The mineral composition of a urinary stone may influence its surgical and medical treatment. Previous attempts at identifying stone composition based on mean Hounsfield Units (HUm) have had varied success. We aimed to evaluate the additional use of standard deviation of HU (HUsd) to more accurately predict stone composition. We identified patients from two centers who had undergone urinary stone treatment between 2006 and 2013 and had mineral stone analysis and a computed tomography (CT) available. HUm and HUsd of the stones were compared with ANOVA. Receiver operative characteristic analysis with area under the curve (AUC), Youden index, and likelihood ratio calculations were performed. Data were available for 466 patients. The major components were calcium oxalate monohydrate (COM), uric acid, hydroxyapatite, struvite, brushite, cystine, and CO dihydrate (COD) in 41.4%, 19.3%, 12.4%, 7.5%, 5.8%, 5.4%, and 4.7% of patients, respectively. The HUm of UA and Br was significantly lower and higher than the HUm of any other stone type, respectively. HUm and HUsd were most accurate in predicting uric acid with an AUC of 0.969 and 0.851, respectively. The combined use of HUm and HUsd resulted in increased positive predictive value and higher likelihood ratios for identifying a stone's mineral composition for all stone types but COM. To the best of our knowledge, this is the first report of CT data aiding in the prediction of brushite stone composition. Both HUm and HUsd can help predict stone composition and their combined use results in higher likelihood ratios influencing probability.

Dynamics of Flexible MLI-type Debris for Accurate Orbit Prediction

Science.gov (United States)

2014-09-01

debris for accurate propagation under perturbations”, in Proceedings of 65th International Astronautical Congress (IAC 2014), Toronto, Canada , 2014...Surveillance Network ( SSN ) was able to detect more than 900 pieces of debris that were at risk to damage operational spacecraft. In February 10, 2009...created two large debris clouds and the SSN reported that 382 pieces of debris from Iridium 33 and 893 pieces from Cosmos 2251 were created, and

An Accurate GPS-IMU/DR Data Fusion Method for Driverless Car Based on a Set of Predictive Models and Grid Constraints.

Science.gov (United States)

Wang, Shiyao; Deng, Zhidong; Yin, Gang

2016-02-24

A high-performance differential global positioning system (GPS)  receiver with real time kinematics provides absolute localization for driverless cars. However, it is not only susceptible to multipath effect but also unable to effectively fulfill precise error correction in a wide range of driving areas. This paper proposes an accurate GPS-inertial measurement unit (IMU)/dead reckoning (DR) data fusion method based on a set of predictive models and occupancy grid constraints. First, we employ a set of autoregressive and moving average (ARMA) equations that have different structural parameters to build maximum likelihood models of raw navigation. Second, both grid constraints and spatial consensus checks on all predictive results and current measurements are required to have removal of outliers. Navigation data that satisfy stationary stochastic process are further fused to achieve accurate localization results. Third, the standard deviation of multimodal data fusion can be pre-specified by grid size. Finally, we perform a lot of field tests on a diversity of real urban scenarios. The experimental results demonstrate that the method can significantly smooth small jumps in bias and considerably reduce accumulated position errors due to DR. With low computational complexity, the position accuracy of our method surpasses existing state-of-the-arts on the same dataset and the new data fusion method is practically applied in our driverless car.

An Accurate GPS-IMU/DR Data Fusion Method for Driverless Car Based on a Set of Predictive Models and Grid Constraints

Directory of Open Access Journals (Sweden)

Shiyao Wang

2016-02-01

Full Text Available A high-performance differential global positioning system (GPS  receiver with real time kinematics provides absolute localization for driverless cars. However, it is not only susceptible to multipath effect but also unable to effectively fulfill precise error correction in a wide range of driving areas. This paper proposes an accurate GPS–inertial measurement unit (IMU/dead reckoning (DR data fusion method based on a set of predictive models and occupancy grid constraints. First, we employ a set of autoregressive and moving average (ARMA equations that have different structural parameters to build maximum likelihood models of raw navigation. Second, both grid constraints and spatial consensus checks on all predictive results and current measurements are required to have removal of outliers. Navigation data that satisfy stationary stochastic process are further fused to achieve accurate localization results. Third, the standard deviation of multimodal data fusion can be pre-specified by grid size. Finally, we perform a lot of field tests on a diversity of real urban scenarios. The experimental results demonstrate that the method can significantly smooth small jumps in bias and considerably reduce accumulated position errors due to DR. With low computational complexity, the position accuracy of our method surpasses existing state-of-the-arts on the same dataset and the new data fusion method is practically applied in our driverless car.

How accurate is anatomic limb alignment in predicting mechanical limb alignment after total knee arthroplasty?

Science.gov (United States)

Lee, Seung Ah; Choi, Sang-Hee; Chang, Moon Jong

2015-10-27

Anatomic limb alignment often differs from mechanical limb alignment after total knee arthroplasty (TKA). We sought to assess the accuracy, specificity, and sensitivity for each of three commonly used ranges for anatomic limb alignment (3-9°, 5-10° and 2-10°) in predicting an acceptable range (neutral ± 3°) for mechanical limb alignment after TKA. We also assessed whether the accuracy of anatomic limb alignment was affected by anatomic variation. This retrospective study included 314 primary TKAs. The alignment of the limb was measured with both anatomic and mechanical methods of measurement. We also measured anatomic variation, including the femoral bowing angle, tibial bowing angle, and neck-shaft angle of the femur. All angles were measured on the same full-length standing anteroposterior radiographs. The accuracy, specificity, and sensitivity for each range of anatomic limb alignment were calculated and compared using mechanical limb alignment as the reference standard. The associations between the accuracy of anatomic limb alignment and anatomic variation were also determined. The range of 2-10° for anatomic limb alignment showed the highest accuracy, but it was only 73 % (3-9°, 65 %; 5-10°, 67 %). The specificity of the 2-10° range was 81 %, which was higher than that of the other ranges (3-9°, 69 %; 5-10°, 67 %). However, the sensitivity of the 2-10° range to predict varus malalignment was only 16 % (3-9°, 35 %; 5-10°, 68 %). In addition, the sensitivity of the 2-10° range to predict valgus malalignment was only 43 % (3-9°, 71 %; 5-10°, 43 %). The accuracy of anatomical limb alignment was lower for knees with greater femoral (odds ratio = 1.2) and tibial (odds ratio = 1.2) bowing. Anatomic limb alignment did not accurately predict mechanical limb alignment after TKA, and its accuracy was affected by anatomic variation. Thus, alignment after TKA should be assessed by measuring mechanical alignment rather than anatomic

Limestone neutralisation of arsenic-rich effluent from a gold mine

CSIR Research Space (South Africa)

De Beer, Morris

2008-03-01

Full Text Available neutralisation of discard leachate containing (10 g/L acid (as CaCO3) and 4,000 mg/L Fe(II)) can be achieved in a limestone neutralisation fluidised-bed reactor, provided that the Fe is oxidised beforehand (Maree et al. 1998). • Fe(II) can be oxidised... 300 mg/L magnesium (as Mg) is present, sulphate can be reduced from 18,000 mg/L (as SO4) to about 2,700 mg/L by gypsum crystallisation and at 0 mg/L Mg to 1,500 mg/L (as SO4). Magnesium keeps the equivalent amount of sulphate in solution. With a...

Bite traces in a turtle carapace fragment from the middle Danian (Lower Paleocene) bryozoan limestone, Faxe, Denmark

DEFF Research Database (Denmark)

Milan, Jesper; Lindow, Bent Erik Kramer; Lauridsen, Bodil Wesenberg

2011-01-01

A fragment of a turtle carapace from the Middle Danian bryozoan limestone at the Faxe quarry, eastern Denmark, is identified as a partial costal plate from the carapace of a chelonioid turtle. The fragment bears traces of three separate acts of predation or scavenging. Two circular bite traces Ni...... either alone or in a row of three, are either from sharks or fish. This is the first record of turtles from the Danian bryozoan limestone exposed in Faxe....... Nihilichnus nihilicus Mikuláš et al. 2006, 4 mm in diameter, situated 2.5 cm apart, are interpreted as crocodylian. Groups of parallel scrapes, Machichnus bohemicus Mikuláš et al. 2006, 4–5 mm long and 0.5 mm wide, are interpreted as bite traces from sharks. Small circular traces, ~1 mm in diameter, found...

Immobilization of Cd, Zn, and Pb from Soil Treated by Limestone with Variation of pH Using a Column Test

Directory of Open Access Journals (Sweden)

Sung-Wook Yun

2015-01-01

Full Text Available Decades of mining in South Korea have resulted in the contamination of large amounts of soil by metals. The most feasible approach to site restoration requires the use of a stabilization agent to reduce metal mobility. This study examined the leaching characteristics of limestone used as a stabilization agent when subjected to solutions of differing pH. In a laboratory-scale column test, solutions with pH values of 3.5, 4.6, and 5.6, representing acidic to nonacidic rainfall, were applied to soil mixed with limestone. Test results indicate that metal components can be released with the addition of acidic solutions, even if the soil is highly alkaline. Cd and Zn, in particular, exhibited abrupt or continuous leaching when exposed to acid solutions, indicating the potential for contamination of water systems as metal-laden soils are exposed to the slightly acidic rainfall typical of South Korea. Treatment using stabilization agents such as limestone may reduce leaching of metals from the contaminated soil. Stabilizing metal-contaminated farmland is an economical and feasible way to reduce pollutants around abandoned metal mines.

Conceptualization of flow and transport in a limestone aquifer by multiple dedicated hydraulic and tracer tests

DEFF Research Database (Denmark)

Mosthaf, Klaus; Brauns, Bentje; Fjordbøge, Annika Sidelmann

2018-01-01

Limestone aquifers are of great interest as a drinking water resource in many countries. They often have a complex crushed and fractured geology, which makes the analysis and description of flow and transport processes in such aquifers a challenging task. In this study, the solute transport behav...

Transient Catalytic Activity of Calcined Dolomitic Limestone in a Fluidized Bed during Gasification of Woody Biomass.

Czech Academy of Sciences Publication Activity Database

Pohořelý, Michael; Jeremiáš, Michal; Skoblia, S.; Beňo, Z.; Šyc, Michal; Svoboda, Karel

2016-01-01

Roč. 30, č. 5 (2016), s. 4065-4071 ISSN 0887-0624 R&D Projects: GA ČR GC14-09692J Institutional support: RVO:67985858 Keywords : fluidized- bed gasification * woody biomass * limestone Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.091, year: 2016

Accurate thermoelastic tensor and acoustic velocities of NaCl

Energy Technology Data Exchange (ETDEWEB)

Marcondes, Michel L., E-mail: michel@if.usp.br [Physics Institute, University of Sao Paulo, Sao Paulo, 05508-090 (Brazil); Chemical Engineering and Material Science, University of Minnesota, Minneapolis, 55455 (United States); Shukla, Gaurav, E-mail: shukla@physics.umn.edu [School of Physics and Astronomy, University of Minnesota, Minneapolis, 55455 (United States); Minnesota supercomputer Institute, University of Minnesota, Minneapolis, 55455 (United States); Silveira, Pedro da [Chemical Engineering and Material Science, University of Minnesota, Minneapolis, 55455 (United States); Wentzcovitch, Renata M., E-mail: wentz002@umn.edu [Chemical Engineering and Material Science, University of Minnesota, Minneapolis, 55455 (United States); Minnesota supercomputer Institute, University of Minnesota, Minneapolis, 55455 (United States)

2015-12-15

Despite the importance of thermoelastic properties of minerals in geology and geophysics, their measurement at high pressures and temperatures are still challenging. Thus, ab initio calculations are an essential tool for predicting these properties at extreme conditions. Owing to the approximate description of the exchange-correlation energy, approximations used in calculations of vibrational effects, and numerical/methodological approximations, these methods produce systematic deviations. Hybrid schemes combining experimental data and theoretical results have emerged as a way to reconcile available information and offer more reliable predictions at experimentally inaccessible thermodynamics conditions. Here we introduce a method to improve the calculated thermoelastic tensor by using highly accurate thermal equation of state (EoS). The corrective scheme is general, applicable to crystalline solids with any symmetry, and can produce accurate results at conditions where experimental data may not exist. We apply it to rock-salt-type NaCl, a material whose structural properties have been challenging to describe accurately by standard ab initio methods and whose acoustic/seismic properties are important for the gas and oil industry.

A NEW CLINICAL PREDICTION CRITERION ACCURATELY DETERMINES A SUBSET OF PATIENTS WITH BILATERAL PRIMARY ALDOSTERONISM BEFORE ADRENAL VENOUS SAMPLING.

Science.gov (United States)

Kocjan, Tomaz; Janez, Andrej; Stankovic, Milenko; Vidmar, Gaj; Jensterle, Mojca

2016-05-01

Adrenal venous sampling (AVS) is the only available method to distinguish bilateral from unilateral primary aldosteronism (PA). AVS has several drawbacks, so it is reasonable to avoid this procedure when the results would not affect clinical management. Our objective was to identify a clinical criterion that can reliably predict nonlateralized AVS as a surrogate for bilateral PA that is not treated surgically. A retrospective diagnostic cross-sectional study conducted at Slovenian national endocrine referral center included 69 consecutive patients (mean age 56 ± 8 years, 21 females) with PA who underwent AVS. PA was confirmed with the saline infusion test (SIT). AVS was performed sequentially during continuous adrenocorticotrophic hormone (ACTH) infusion. The main outcome measures were variables associated with nonlateralized AVS to derive a clinical prediction rule. Sixty-seven (97%) patients had a successful AVS and were included in the statistical analysis. A total of 39 (58%) patients had nonlateralized AVS. The combined criterion of serum potassium ≥3.5 mmol/L, post-SIT aldosterone AVS. The best overall classification accuracy (50/67 = 75%) was achieved using the post-SIT aldosterone level AVS. Our clinical prediction criterion appears to accurately determine a subset of patients with bilateral PA who could avoid unnecessary AVS and immediately commence with medical treatment.

Estimation of deep infiltration in unsaturated limestone environments using cave lidar and drip count data

Science.gov (United States)

Mahmud, K.; Mariethoz, G.; Baker, A.; Treble, P. C.; Markowska, M.; McGuire, E.

2016-01-01

Limestone aeolianites constitute karstic aquifers covering much of the western and southern Australian coastal fringe. They are a key groundwater resource for a range of industries such as winery and tourism, and provide important ecosystem services such as habitat for stygofauna. Moreover, recharge estimation is important for understanding the water cycle, for contaminant transport, for water management, and for stalagmite-based paleoclimate reconstructions. Caves offer a natural inception point to observe both the long-term groundwater recharge and the preferential movement of water through the unsaturated zone of such limestone. With the availability of automated drip rate logging systems and remote sensing techniques, it is now possible to deploy the combination of these methods for larger-scale studies of infiltration processes within a cave. In this study, we utilize a spatial survey of automated cave drip monitoring in two large chambers of Golgotha Cave, south-western Western Australia (SWWA), with the aim of better understanding infiltration water movement and the relationship between infiltration, stalactite morphology, and unsaturated zone recharge. By applying morphological analysis of ceiling features from Terrestrial LiDAR (T-LiDAR) data, coupled with drip time series and climate data from 2012 to 2014, we demonstrate the nature of the relationships between infiltration through fractures in the limestone and unsaturated zone recharge. Similarities between drip rate time series are interpreted in terms of flow patterns, cave chamber morphology, and lithology. Moreover, we develop a new technique to estimate recharge in large-scale caves, engaging flow classification to determine the cave ceiling area covered by each flow category and drip data for the entire observation period, to calculate the total volume of cave discharge. This new technique can be applied to other cave sites to identify highly focussed areas of recharge and can help to better

Learning a Weighted Sequence Model of the Nucleosome Core and Linker Yields More Accurate Predictions in Saccharomyces cerevisiae and Homo sapiens

Science.gov (United States)

Reynolds, Sheila M.; Bilmes, Jeff A.; Noble, William Stafford

2010-01-01

DNA in eukaryotes is packaged into a chromatin complex, the most basic element of which is the nucleosome. The precise positioning of the nucleosome cores allows for selective access to the DNA, and the mechanisms that control this positioning are important pieces of the gene expression puzzle. We describe a large-scale nucleosome pattern that jointly characterizes the nucleosome core and the adjacent linkers and is predominantly characterized by long-range oscillations in the mono, di- and tri-nucleotide content of the DNA sequence, and we show that this pattern can be used to predict nucleosome positions in both Homo sapiens and Saccharomyces cerevisiae more accurately than previously published methods. Surprisingly, in both H. sapiens and S. cerevisiae, the most informative individual features are the mono-nucleotide patterns, although the inclusion of di- and tri-nucleotide features results in improved performance. Our approach combines a much longer pattern than has been previously used to predict nucleosome positioning from sequence—301 base pairs, centered at the position to be scored—with a novel discriminative classification approach that selectively weights the contributions from each of the input features. The resulting scores are relatively insensitive to local AT-content and can be used to accurately discriminate putative dyad positions from adjacent linker regions without requiring an additional dynamic programming step and without the attendant edge effects and assumptions about linker length modeling and overall nucleosome density. Our approach produces the best dyad-linker classification results published to date in H. sapiens, and outperforms two recently published models on a large set of S. cerevisiae nucleosome positions. Our results suggest that in both genomes, a comparable and relatively small fraction of nucleosomes are well-positioned and that these positions are predictable based on sequence alone. We believe that the bulk of the

Learning a weighted sequence model of the nucleosome core and linker yields more accurate predictions in Saccharomyces cerevisiae and Homo sapiens.

Directory of Open Access Journals (Sweden)

Sheila M Reynolds

2010-07-01

Full Text Available DNA in eukaryotes is packaged into a chromatin complex, the most basic element of which is the nucleosome. The precise positioning of the nucleosome cores allows for selective access to the DNA, and the mechanisms that control this positioning are important pieces of the gene expression puzzle. We describe a large-scale nucleosome pattern that jointly characterizes the nucleosome core and the adjacent linkers and is predominantly characterized by long-range oscillations in the mono, di- and tri-nucleotide content of the DNA sequence, and we show that this pattern can be used to predict nucleosome positions in both Homo sapiens and Saccharomyces cerevisiae more accurately than previously published methods. Surprisingly, in both H. sapiens and S. cerevisiae, the most informative individual features are the mono-nucleotide patterns, although the inclusion of di- and tri-nucleotide features results in improved performance. Our approach combines a much longer pattern than has been previously used to predict nucleosome positioning from sequence-301 base pairs, centered at the position to be scored-with a novel discriminative classification approach that selectively weights the contributions from each of the input features. The resulting scores are relatively insensitive to local AT-content and can be used to accurately discriminate putative dyad positions from adjacent linker regions without requiring an additional dynamic programming step and without the attendant edge effects and assumptions about linker length modeling and overall nucleosome density. Our approach produces the best dyad-linker classification results published to date in H. sapiens, and outperforms two recently published models on a large set of S. cerevisiae nucleosome positions. Our results suggest that in both genomes, a comparable and relatively small fraction of nucleosomes are well-positioned and that these positions are predictable based on sequence alone. We believe that the

Learning a weighted sequence model of the nucleosome core and linker yields more accurate predictions in Saccharomyces cerevisiae and Homo sapiens.

Science.gov (United States)

Reynolds, Sheila M; Bilmes, Jeff A; Noble, William Stafford

2010-07-08

DNA in eukaryotes is packaged into a chromatin complex, the most basic element of which is the nucleosome. The precise positioning of the nucleosome cores allows for selective access to the DNA, and the mechanisms that control this positioning are important pieces of the gene expression puzzle. We describe a large-scale nucleosome pattern that jointly characterizes the nucleosome core and the adjacent linkers and is predominantly characterized by long-range oscillations in the mono, di- and tri-nucleotide content of the DNA sequence, and we show that this pattern can be used to predict nucleosome positions in both Homo sapiens and Saccharomyces cerevisiae more accurately than previously published methods. Surprisingly, in both H. sapiens and S. cerevisiae, the most informative individual features are the mono-nucleotide patterns, although the inclusion of di- and tri-nucleotide features results in improved performance. Our approach combines a much longer pattern than has been previously used to predict nucleosome positioning from sequence-301 base pairs, centered at the position to be scored-with a novel discriminative classification approach that selectively weights the contributions from each of the input features. The resulting scores are relatively insensitive to local AT-content and can be used to accurately discriminate putative dyad positions from adjacent linker regions without requiring an additional dynamic programming step and without the attendant edge effects and assumptions about linker length modeling and overall nucleosome density. Our approach produces the best dyad-linker classification results published to date in H. sapiens, and outperforms two recently published models on a large set of S. cerevisiae nucleosome positions. Our results suggest that in both genomes, a comparable and relatively small fraction of nucleosomes are well-positioned and that these positions are predictable based on sequence alone. We believe that the bulk of the

Cluster abundance in chameleon f ( R ) gravity I: toward an accurate halo mass function prediction

Energy Technology Data Exchange (ETDEWEB)

Cataneo, Matteo; Rapetti, David [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen (Denmark); Lombriser, Lucas [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); Li, Baojiu, E-mail: matteoc@dark-cosmology.dk, E-mail: drapetti@dark-cosmology.dk, E-mail: llo@roe.ac.uk, E-mail: baojiu.li@durham.ac.uk [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

2016-12-01

We refine the mass and environment dependent spherical collapse model of chameleon f ( R ) gravity by calibrating a phenomenological correction inspired by the parameterized post-Friedmann framework against high-resolution N -body simulations. We employ our method to predict the corresponding modified halo mass function, and provide fitting formulas to calculate the enhancement of the f ( R ) halo abundance with respect to that of General Relativity (GR) within a precision of ∼< 5% from the results obtained in the simulations. Similar accuracy can be achieved for the full f ( R ) mass function on the condition that the modeling of the reference GR abundance of halos is accurate at the percent level. We use our fits to forecast constraints on the additional scalar degree of freedom of the theory, finding that upper bounds competitive with current Solar System tests are within reach of cluster number count analyses from ongoing and upcoming surveys at much larger scales. Importantly, the flexibility of our method allows also for this to be applied to other scalar-tensor theories characterized by a mass and environment dependent spherical collapse.

Physiological and behavioral responses of stonefly nymphs to enhanced limestone treatment of acid mine drainage.

Science.gov (United States)

Cole, M B; Arnold, D E; Watten, B J

2001-03-01

A new acid mine drainage (AMD) treatment system uses pulsed, fluidized beds of limestone, and carbon dioxide pretreatment of influent AMD, to enhance limestone neutralization of AMD. We conducted laboratory studies to evaluate the behavior and physiology of larval stoneflies (Pteronarcys proteus, Plecoptera) exposed to effluents produced by the treatment system. Survival, sodium balance, drift, and feeding responses by P. proteus to treated and untreated AMD were examined. P. proteus nymphs exhibited significant losses of whole body sodium in exposures to untreated AMD. Nymphs exposed to treated effluents experienced no loss of whole-body sodium. Nymphs exposed to untreated AMD showed elevated drift rates and depressed feeding rates relative to those of nymphs exposed to treated AMD, and to AMD-free controls. No significant differences in feeding or drift behavior occurred between nymphs exposed to treated effluents and those exposed to AMD-free controls. The treatment system, with and without CO2 pretreatment, provided water that was not toxic to the test animals, and that allowed normal behavioral and physiological function.

Limestone fragmentation and attrition during fluidized bed oxyfiring

Energy Technology Data Exchange (ETDEWEB)

Fabrizio Scala; Piero Salatino [Istituto di Ricerche sulla Combustione - CNR, Napoli (Italy)

2010-04-15

Attrition/fragmentation of limestone under simulated fluidized bed oxyfiring conditions was investigated by means of an experimental protocol that had been previously developed for characterization of attrition/fragmentation of sorbents in air-blown atmospheric fluidized bed combustors. The protocol was based on the use of different and mutually complementary techniques. The extent and pattern of attrition by surface wear in the dense phase of a fluidized bed were assessed in experiments carried out with a bench scale fluidized bed combustor under simulated oxyfiring conditions. Sorbent samples generated during simulated oxyfiring tests were further characterized from the standpoint of fragmentation upon high velocity impact by means of a purposely designed particle impactor. Results showed that under calcination-hindered conditions attrition and fragmentation patterns are much different from those occurring under air-blown atmospheric combustion conditions. Noteworthy, attrition/fragmentation enhanced particle sulfation by continuously regenerating the exposed particle surface. 13 refs., 8 figs.

A Stranger in the Midst: Searching for Relict Grains from Rare Meteorite Types in Mid-Ordovician Limestone Strata

Science.gov (United States)

Martin, E.; Schmitz, B.

2016-08-01

A layer of Mid-Ordovician limestone harbors exceptional amounts of L-chondritic chromite grains. The layer also contains grains from potentially rarer types of meteorites, following the discovery of the fossil meteorite Österplana 065.

Comments on "Proposal for a Regenerative High-Temperature Process for Coal Gas Cleanup with Calcined Limestone"

Czech Academy of Sciences Publication Activity Database

Hartman, Miloslav; Trnka, Otakar

2002-01-01

Roč. 41, č. 24 (2002), s. 6207-6208 ISSN 0888-5885 R&D Projects: GA ČR GA203/98/0101; GA AV ČR IAA4072711 Keywords : H2S removal * coal gas * limestone Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.247, year: 2002

Influence of limestone powder on the reaction kinetics and mechanical properties of sodium carbonate activated slag

NARCIS (Netherlands)

Yuan, B.; Yu, Q.; Brouwers, H.J.H.

2016-01-01

The effects of limestone powder (LP) on the performance of Portland cement based composites have been extensively studied, considering that LP not only acts as nuclei sites, but that it is also chemically involved in the hydration process, which improves the reaction degree at the early age. In high

Fast and Accurate Prediction of Numerical Relativity Waveforms from Binary Black Hole Coalescences Using Surrogate Models.

Science.gov (United States)

Blackman, Jonathan; Field, Scott E; Galley, Chad R; Szilágyi, Béla; Scheel, Mark A; Tiglio, Manuel; Hemberger, Daniel A

2015-09-18

Simulating a binary black hole coalescence by solving Einstein's equations is computationally expensive, requiring days to months of supercomputing time. Using reduced order modeling techniques, we construct an accurate surrogate model, which is evaluated in a millisecond to a second, for numerical relativity (NR) waveforms from nonspinning binary black hole coalescences with mass ratios in [1, 10] and durations corresponding to about 15 orbits before merger. We assess the model's uncertainty and show that our modeling strategy predicts NR waveforms not used for the surrogate's training with errors nearly as small as the numerical error of the NR code. Our model includes all spherical-harmonic _{-2}Y_{ℓm} waveform modes resolved by the NR code up to ℓ=8. We compare our surrogate model to effective one body waveforms from 50M_{⊙} to 300M_{⊙} for advanced LIGO detectors and find that the surrogate is always more faithful (by at least an order of magnitude in most cases).

Assessment of Rock Slope Stability in Limestone Quarries in the Tournai's Region (Belgium) Using Structural Data

Science.gov (United States)

Tshibangu, Jean-Pierre; Deloge, K. Pierre-Alexandre; Deschamps, Benoît; Coudyzer, Christophe

The Tournais region is characterised by famous outcrops of carboniferous limestone which is mined out for cement and raw material production. The four main quarries found in the Region, i.e. Gaurain-Ramecroix, Milieu, Antoing and Lemay; are owned by the three main cement producers in Belgium: Italcimenti, Holcim and CBR. The global production of limestone is about 20 millions tons per year, giving big pits with depths up to 150 m. With the growth of the pits, the quarries are approaching each other leading to the problem of managing the reserves contained in the separating walls and their mechanical stability. The limestone deposit is composed of different seams having varying thickness, chemical com- position and even mechanical properties. The deposit has an overall horizontal dip and is intersected by two main sets of discontinuities with a spacing of about 10 m or less. It is also crossed by a set of east to west faults but the quarries are implanted in the in between areas, so to not be crossed by these faults. The layers and specially the shallow ones are characterised by a typical karstic weathering giving open or filled cavities. This paper presents the global work quarried out in order to study the stability of the Lemays quarry. First a description of the orientation and spacing of discontinuities is presented, and an attempt made to correlate to the development of weathering. Mechanical laboratory tests have been performed and a qualification of the rock mass assessed. A coupled approach is then presented using a mining planning analysis and mechanical simulation (i.e. Finite Element method).

Cyclic carbonation calcination studies of limestone and dolomite for CO{sub 2} separation from combustion flue gases - article no. 011801

Energy Technology Data Exchange (ETDEWEB)

Senthoorselvan, S.; Gleis, S.; Hartmut, S.; Yrjas, P.; Hupa, M. [TUM, Garching (Germany)

2009-01-15

Naturally occurring limestone and dolomite samples, originating from different geographical locations, were tested as potential sorbents for carbonation/calcination based CO{sub 2} capture from combustion flue gases. Samples have been studied in a thermogravimetric analyzer under simulated flue gas conditions at three calcination temperatures, viz., 750{sup o}C, 875{sup o}C, and 930{sup o}C for four carbonation calcination reaction (CCR) cycles. The dolomite sample exhibited the highest rate of carbonation than the tested limestones. At the third cycle, its CO{sub 2} capture capacity per kilogram of the sample was nearly equal to that of Gotland, the highest reacting limestone tested. At the fourth cycle it surpassed Gotland, despite the fact that the CaCO{sub 3} content of the Sibbo dolomite was only 2/3 of that of the Gotland. Decay coefficients were calculated by a curve fitting exercise and its value is lowest for the Sibbo dolomite. That means, most probably its capture capacity per kilogram of the sample would remain higher well beyond the fourth cycle. There was a strong correlation between the calcination temperature, the specific surface area of the calcined samples, and the degree of carbonation. It was observed that the higher the calcination temperature, the lower the sorbent reactivity. For a given limestone/dolomite sample, sorbents CO{sub 2} capture capacity depended on the number of CCR cycles and the calcination temperature. According to the equilibrium thermodynamics, the CO{sub 2} partial pressure in the calciner should be lowered to lower the calcination temperature. This can be achieved by additional steam supply into the calciner. Steam could then be condensed in an external condenser to single out the CO{sub 2} stream from the exit gas mixture of the calciner. A calciner design based on this concept is illustrated.

Zinc and nickel removal in limestone based treatment of acid mine drainage: The relative role of adsorption and co-precipitation

International Nuclear Information System (INIS)

Miller, Andrew; Wildeman, Thomas; Figueroa, Linda

2013-01-01

Highlights: • Limestone treatment of mining impacted water was simulated in batch reactors. • Zinc and nickel removals were quantified/characterized with a sequential extraction. • Removals were described with a surface complexation and a surface precipitation model. • Extraction/modeling results imply mechanisms beyond adsorption dominate metal removal. - Abstract: Mining influenced water may contain high metal and sulfate loads, and have low pH (acid mine drainage). Removal of these metals prior to environmental discharge is critical to maintain ecosystem vitality. Limestone based passive treatment systems are commonly used for pH neutralization. The same conditions that lead to pH neutralization may also remove a substantial amount of metals from solution, but the connection between treatment conditions and metal removal are not well understood. In this study, zinc and nickel removals are quantified in batch reactor simulated limestone treatment of acid mine drainage. The resulting solid phase is characterized with a sequential extraction procedure, and the removals are interpreted using surface complexation and surface precipitation models. Zinc and nickel removals are closely linked to the initial iron concentration in the mine water, but are also affected by pH, alkalinity, calcium and sulfate concentrations. The surface complexation model was based on literature descriptions of hydrous ferric oxide. In order to obtain a sufficient fit to the data, the surface site density was increased to an unrealistically high value. Uptake data was also fit to an existing surface precipitation model. The values used are similar to those found in previous studies. Both models indicate that adsorption is not the dominant removal process in the treatment system. Using adsorption only models will generally underpredict metal removals within limestone based treatment systems

Accurate prediction of complex free surface flow around a high speed craft using a single-phase level set method

Science.gov (United States)

Broglia, Riccardo; Durante, Danilo

2017-11-01

This paper focuses on the analysis of a challenging free surface flow problem involving a surface vessel moving at high speeds, or planing. The investigation is performed using a general purpose high Reynolds free surface solver developed at CNR-INSEAN. The methodology is based on a second order finite volume discretization of the unsteady Reynolds-averaged Navier-Stokes equations (Di Mascio et al. in A second order Godunov—type scheme for naval hydrodynamics, Kluwer Academic/Plenum Publishers, Dordrecht, pp 253-261, 2001; Proceedings of 16th international offshore and polar engineering conference, San Francisco, CA, USA, 2006; J Mar Sci Technol 14:19-29, 2009); air/water interface dynamics is accurately modeled by a non standard level set approach (Di Mascio et al. in Comput Fluids 36(5):868-886, 2007a), known as the single-phase level set method. In this algorithm the governing equations are solved only in the water phase, whereas the numerical domain in the air phase is used for a suitable extension of the fluid dynamic variables. The level set function is used to track the free surface evolution; dynamic boundary conditions are enforced directly on the interface. This approach allows to accurately predict the evolution of the free surface even in the presence of violent breaking waves phenomena, maintaining the interface sharp, without any need to smear out the fluid properties across the two phases. This paper is aimed at the prediction of the complex free-surface flow field generated by a deep-V planing boat at medium and high Froude numbers (from 0.6 up to 1.2). In the present work, the planing hull is treated as a two-degree-of-freedom rigid object. Flow field is characterized by the presence of thin water sheets, several energetic breaking waves and plungings. The computational results include convergence of the trim angle, sinkage and resistance under grid refinement; high-quality experimental data are used for the purposes of validation, allowing to

Salt weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures

Science.gov (United States)

Aly, Nevin; Gomez-Heras, Miguel; Hamed, Ayman; Alvarez de Buergo, Monica

2013-04-01

weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures Nevin Aly Mohamed (1), Miguel Gomez - Heras(2), Ayman Hamed Ahmed (1), and Monica Alvarez de Buergo(2). (1) Faculty of Pet. & Min. Engineering- Suez Canal University, Suez, Egypt, (2) Instituto de Geociencias (CSIC-UCM) Madrid. Spain. Limestone is one of the most frequent building stones in Egypt and is used since the time of ancient Egyptians and salt weathering is one of the main threats to its conservation. Most of the limestone used in historical monuments in Cairo is a biomicrite extracted from the Mid-Eocene Mokattam Group. During this work, cylindrical samples (2.4 cm diameter and approx. 4.8 cm length) were subjected, in a purpose-made simulation chamber, to simulated laboratory weathering tests with fixed salt concentration (10% weight NaCl solution), at different temperatures, which were kept constant throughout each test (10, 20, 30, 40 oC). During each test, salt solutions flowed continuously imbibing samples by capilarity. Humidity within the simulation chamber was reduced using silica gel to keep it low and constant to increase evaporation rate. Temperature, humidity inside the simulation chamber and samples weight were digitally monitored during each test. Results show the advantages of the proposed experimental methodology using a continuous flow of salt solutions and shed light on the effect of temperature on the dynamics of salt crystallization on and within samples. Research funded by mission sector of high education ministry, Egypt and Geomateriales S2009/MAT-1629.

Investigation in order to defined the technological process of obtaining fillers for use in various industries on the basis of limestone 'Gigovići'-Ulcinj

Directory of Open Access Journals (Sweden)

Radulović Dragan S.

2017-01-01

Full Text Available This paper presents results of investigations of the possibility of using 'Gigovići'-Ulcinj limestone (Republic Montenegro as filler in various industry branches. Micronization methods, granulometric composition, oil and water absorption and degree of whiteness were investigated, and chemical and thermal analyses (DT/TG were performed. Physico-chemical properties of this limestone classify it among high quality carbonate raw materials with relatively high CaCO3 content of 98.16 %, as well as low MgCO3 content of 1.53 % and low silicate content (SiO2 0.30 %. Its quality satisfies requirements of standards on using of calcium carbonate as filler in industry of paints and coatings; paper industry, rubber and PVC industry; glass industry; production of mineral fertilizers; foundry industry; sugar industry and metallurgy. Due to the low degree of whiteness (85.25 % 'Gigovići' limestone cannot be used in pharmaceutical and cosmetics industry. Due to relatively high content of MgO (0.73 % and Fe (340 ppm, as well as high content of heavy metals, Cu (18 ppm, Ni (24 ppm and Cd (9 ppm, 'Gigovići' limestone cannot be used, in production of cattle feed and for neutralization of acidic soils.

Neural network prediction of carbonate lithofacies from well logs, Big Bow and Sand Arroyo Creek fields, Southwest Kansas

Science.gov (United States)

Qi, L.; Carr, T.R.

2006-01-01

In the Hugoton Embayment of southwestern Kansas, St. Louis Limestone reservoirs have relatively low recovery efficiencies, attributed to the heterogeneous nature of the oolitic deposits. This study establishes quantitative relationships between digital well logs and core description data, and applies these relationships in a probabilistic sense to predict lithofacies in 90 uncored wells across the Big Bow and Sand Arroyo Creek fields. In 10 wells, a single hidden-layer neural network based on digital well logs and core described lithofacies of the limestone depositional texture was used to train and establish a non-linear relationship between lithofacies assignments from detailed core descriptions and selected log curves. Neural network models were optimized by selecting six predictor variables and automated cross-validation with neural network parameters and then used to predict lithofacies on the whole data set of the 2023 half-foot intervals from the 10 cored wells with the selected network size of 35 and a damping parameter of 0.01. Predicted lithofacies results compared to actual lithofacies displays absolute accuracies of 70.37-90.82%. Incorporating adjoining lithofacies, within-one lithofacies improves accuracy slightly (93.72%). Digital logs from uncored wells were batch processed to predict lithofacies and probabilities related to each lithofacies at half-foot resolution corresponding to log units. The results were used to construct interpolated cross-sections and useful depositional patterns of St. Louis lithofacies were illustrated, e.g., the concentration of oolitic deposits (including lithofacies 5 and 6) along local highs and the relative dominance of quartz-rich carbonate grainstone (lithofacies 1) in the zones A and B of the St. Louis Limestone. Neural network techniques are applicable to other complex reservoirs, in which facies geometry and distribution are the key factors controlling heterogeneity and distribution of rock properties. Future work

Hounsfield unit density accurately predicts ESWL success.

Science.gov (United States)

Magnuson, William J; Tomera, Kevin M; Lance, Raymond S

2005-01-01

Extracorporeal shockwave lithotripsy (ESWL) is a commonly used non-invasive treatment for urolithiasis. Helical CT scans provide much better and detailed imaging of the patient with urolithiasis including the ability to measure density of urinary stones. In this study we tested the hypothesis that density of urinary calculi as measured by CT can predict successful ESWL treatment. 198 patients were treated at Alaska Urological Associates with ESWL between January 2002 and April 2004. Of these 101 met study inclusion with accessible CT scans and stones ranging from 5-15 mm. Follow-up imaging demonstrated stone freedom in 74.2%. The overall mean Houndsfield density value for stone-free compared to residual stone groups were significantly different ( 93.61 vs 122.80 p ESWL for upper tract calculi between 5-15mm.

Sulfur determination in concrete samples using laser-induced breakdown spectroscopy and limestone standards

Science.gov (United States)

Hrdlička, Aleš; Hegrová, Jitka; Novotný, Karel; Kanický, Viktor; Prochazka, David; Novotný, Jan; Modlitbová, Pavlína; Sládková, Lucia; Pořízka, Pavel; Kaiser, Jozef

2018-04-01

A LIBS equipment operating at 532 nm was optimized and used for sulfur determination in concrete samples. The influence of He atmosphere in a gas-tight chamber (1000-200 mbar) on S I 921.29 nm line sensitivity, signal-to-background and signal-to-noise ratio was studied at gate delays 100-2000 ns. Wide range of gate delays from 500 to about 1000 ns and pressures from several hundreds of mbar to the atmospheric pressure can be used for the desired detection of sulfur. The LIBS quantification was done using a simple calibration method. A synthetic limestone enriched by defined amounts of sodium sulfate was newly employed for direct quantification of S in concrete. This powder material was pressed into pellets and ablated with the LIBS system. The average content of sulfur as SO3 in the samples was 0.41-0.70 wt% by LIBS and 0.43-0.61 wt% by a reference standard procedure employing gravimetry and Inductively Coupled Plasma Triple Quad Mass Spectrometry (ICP-QQQMS). The uncertainty of the yielded LIBS results covers also the dispersion of the points in the calibration line and ranges from 16 to 28% at the probability level of 95%. The uncertainty of the ICP-QQQMS results was almost 10%. No correction on different signal response on the limestone and on the concrete was necessary.

Respiratory variation in peak aortic velocity accurately predicts fluid responsiveness in children undergoing neurosurgery under general anesthesia.

Science.gov (United States)

Morparia, Kavita G; Reddy, Srijaya K; Olivieri, Laura J; Spaeder, Michael C; Schuette, Jennifer J

2018-04-01

The determination of fluid responsiveness in the critically ill child is of vital importance, more so as fluid overload becomes increasingly associated with worse outcomes. Dynamic markers of volume responsiveness have shown some promise in the pediatric population, but more research is needed before they can be adopted for widespread use. Our aim was to investigate effectiveness of respiratory variation in peak aortic velocity and pulse pressure variation to predict fluid responsiveness, and determine their optimal cutoff values. We performed a prospective, observational study at a single tertiary care pediatric center. Twenty-one children with normal cardiorespiratory status undergoing general anesthesia for neurosurgery were enrolled. Respiratory variation in peak aortic velocity (ΔVpeak ao) was measured both before and after volume expansion using a bedside ultrasound device. Pulse pressure variation (PPV) value was obtained from the bedside monitor. All patients received a 10 ml/kg fluid bolus as volume expansion, and were qualified as responders if stroke volume increased >15% as a result. Utility of ΔVpeak ao and PPV and to predict responsiveness to volume expansion was investigated. A baseline ΔVpeak ao value of greater than or equal to 12.3% best predicted a positive response to volume expansion, with a sensitivity of 77%, specificity of 89% and area under receiver operating characteristic curve of 0.90. PPV failed to demonstrate utility in this patient population. Respiratory variation in peak aortic velocity is a promising marker for optimization of perioperative fluid therapy in the pediatric population and can be accurately measured using bedside ultrasonography. More research is needed to evaluate the lack of effectiveness of pulse pressure variation for this purpose.

In situ vitrification of Oak Ridge National Laboratory soil and limestone

International Nuclear Information System (INIS)

Carter, J.G.; Bates, S.O.; Maupin, G.D.

1987-03-01

Process feasibility studies were successfully performed on two different developmental scales to determine the technical application of in situ vitrification (ISV) to Oak Ridge National Laboratory (ORNL) intermediate-level waste. In the laboratory, testing was performed on crucibles containing quantities of 50% ORNL soil and 50% ORNL limestone. In the engineering-scale testing, a 1/12-scaled simulation of ORNL Trench 7 was constructed and vitrified, resulting in waste product soil and limestone concentrations of 68% and 32%, respectively. Results from the two scales of testing indicate that the ORNL intermediate-level waste sites may be successfully processed by ISV; the waste form will retain significant quantities of the cesium and strontium. Because 137 Cs is the major component of the radionuclide inventory in the ORNL seepage pits and trenches, final field process decontamination factors (i.e., off gas at the ground surface relative to the waste inventory) of 10 4 are desired to minimize activity buildup in the off-gas system. These values were realized during the engineering-scale test for both cesium and strontium. The vitrified material effectively contained 99.996% of the cesium and strontium placed in the engineering-scale test. This is equivalent to decontamination factors of greater than 10 4 . Volume reduction for the engineering-scale test was 60%. No migration of the cesium to the uncontaminated surrounding soil was detected. These favorable results indicate that, once verified in a pilot-scale test, an adequately designed ISV system could be produced to treat the ORNL seepage pits and trenches without excessive activity accumulation in the off-gas treatment system

Non-isothermal kinetics model to predict accurate phase transformation and hardness of 22MnB5 boron steel

Energy Technology Data Exchange (ETDEWEB)

Bok, H.-H.; Kim, S.N.; Suh, D.W. [Graduate Institute of Ferrous Technology, POSTECH, San 31, Hyoja-dong, Nam-gu, Pohang, Gyeongsangbuk-do (Korea, Republic of); Barlat, F., E-mail: f.barlat@postech.ac.kr [Graduate Institute of Ferrous Technology, POSTECH, San 31, Hyoja-dong, Nam-gu, Pohang, Gyeongsangbuk-do (Korea, Republic of); Lee, M.-G., E-mail: myounglee@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Anam-dong, Seongbuk-gu, Seoul (Korea, Republic of)

2015-02-25

A non-isothermal phase transformation kinetics model obtained by modifying the well-known JMAK approach is proposed for application to a low carbon boron steel (22MnB5) sheet. In the modified kinetics model, the parameters are functions of both temperature and cooling rate, and can be identified by a numerical optimization method. Moreover, in this approach the transformation start and finish temperatures are variable instead of the constants that depend on chemical composition. These variable reference temperatures are determined from the measured CCT diagram using dilatation experiments. The kinetics model developed in this work captures the complex transformation behavior of the boron steel sheet sample accurately. In particular, the predicted hardness and phase fractions in the specimens subjected to a wide range of cooling rates were validated by experiments.

D-cracking field performance of portland cement concrete pavements containing limestone in Kansas : phase 1 report : technical summary.

Science.gov (United States)

2012-05-01

Introduction: Premature deterioration of concrete pavement due to D-cracking has been a problem in Kansas since the 1930s. Limestone is the major source of coarse aggregate in eastern Kansas where the majority of the concrete pavements are constructe...

Accurate density functional prediction of molecular electron affinity with the scaling corrected Kohn–Sham frontier orbital energies

Science.gov (United States)

Zhang, DaDi; Yang, Xiaolong; Zheng, Xiao; Yang, Weitao

2018-04-01

Electron affinity (EA) is the energy released when an additional electron is attached to an atom or a molecule. EA is a fundamental thermochemical property, and it is closely pertinent to other important properties such as electronegativity and hardness. However, accurate prediction of EA is difficult with density functional theory methods. The somewhat large error of the calculated EAs originates mainly from the intrinsic delocalisation error associated with the approximate exchange-correlation functional. In this work, we employ a previously developed non-empirical global scaling correction approach, which explicitly imposes the Perdew-Parr-Levy-Balduz condition to the approximate functional, and achieve a substantially improved accuracy for the calculated EAs. In our approach, the EA is given by the scaling corrected Kohn-Sham lowest unoccupied molecular orbital energy of the neutral molecule, without the need to carry out the self-consistent-field calculation for the anion.

Effect of computational grid on accurate prediction of a wind turbine rotor using delayed detached-eddy simulations

Energy Technology Data Exchange (ETDEWEB)

Bangga, Galih; Weihing, Pascal; Lutz, Thorsten; Krämer, Ewald [University of Stuttgart, Stuttgart (Germany)

2017-05-15

The present study focuses on the impact of grid for accurate prediction of the MEXICO rotor under stalled conditions. Two different blade mesh topologies, O and C-H meshes, and two different grid resolutions are tested for several time step sizes. The simulations are carried out using Delayed detached-eddy simulation (DDES) with two eddy viscosity RANS turbulence models, namely Spalart- Allmaras (SA) and Menter Shear stress transport (SST) k-ω. A high order spatial discretization, WENO (Weighted essentially non- oscillatory) scheme, is used in these computations. The results are validated against measurement data with regards to the sectional loads and the chordwise pressure distributions. The C-H mesh topology is observed to give the best results employing the SST k-ω turbulence model, but the computational cost is more expensive as the grid contains a wake block that increases the number of cells.

Combining first-principles and data modeling for the accurate prediction of the refractive index of organic polymers

Science.gov (United States)

Afzal, Mohammad Atif Faiz; Cheng, Chong; Hachmann, Johannes

2018-06-01

Organic materials with a high index of refraction (RI) are attracting considerable interest due to their potential application in optic and optoelectronic devices. However, most of these applications require an RI value of 1.7 or larger, while typical carbon-based polymers only exhibit values in the range of 1.3-1.5. This paper introduces an efficient computational protocol for the accurate prediction of RI values in polymers to facilitate in silico studies that can guide the discovery and design of next-generation high-RI materials. Our protocol is based on the Lorentz-Lorenz equation and is parametrized by the polarizability and number density values of a given candidate compound. In the proposed scheme, we compute the former using first-principles electronic structure theory and the latter using an approximation based on van der Waals volumes. The critical parameter in the number density approximation is the packing fraction of the bulk polymer, for which we have devised a machine learning model. We demonstrate the performance of the proposed RI protocol by testing its predictions against the experimentally known RI values of 112 optical polymers. Our approach to combine first-principles and data modeling emerges as both a successful and a highly economical path to determining the RI values for a wide range of organic polymers.

Application of restoration ecology principles to the practice of limestone quarry rehabilitation in Lebanon

International Nuclear Information System (INIS)

Khater, C.; Arnaud, M.

2007-01-01

Restoration ecology is an emerging science dealing with applied ecology and aiming at ''helping nature to recreate itself''. This comprehensive paper presents the findings and main results related to the analysis of natural vegetation dynamics on abandoned limestone quarries in Mediterranean environment. It aims to answer three basic questions: where, when and how should intervention by ecological restoration be achieved in abandoned limestone quarries. Results show that quarries are heterogeneous ecosystems and interventional strategies should be planned according to the different landforms observed. Quarry faces potentially host a particular saxicolous flora often composed of rare and endemic species, intervention is not recommended, unless required by urban planning issues. Intervention on platforms can be very expensive (substratum fracturing) and involves heavy engineering works. Restoration on quarry embankments aims at orienting and accelerating natural regeneration processes in order to shortcut the first stages naturally dominated by annuals and ruderal species. 27 species suitable for revegetation purposes have been identified for the different bioclimatic levels in Lebanon. They respond to two major criteria: availability in the natural surroundings (indigenous species) and adaptability to local conditions (pioneer adapted species). In conclusion, this paper suggests future openings for a development field integrating economical opportunities on solid scientific bases. (author)

Effects of limestone, N, K and Mg fertilizers on Mg absorption by oats and barley

Energy Technology Data Exchange (ETDEWEB)

Alston, A M

1966-01-01

Oats grown in a pot experiment on two sandy loams were sampled at four stages of growth. Neither KCl nor MgSO/sub 4/. 7H/sub 2/O had any effect on yield but % Mg and total Mg uptake were consistently decreased by applying K and increased by applying Mg. Ca(NO/sub 3/)/sub 2/ increased % Mg more than did (NH/sub 4/)/sub 2/SO/sub 4/, but yield and total Mg uptake were higher where (NH/sub 4/)/sub 2/SO/sub 4/ was applied. The effects of fertilizers were similar on both soils. The effects of applying (NH/sub 4/)/sub 2/SO/sub 4/ and NaNO/sub 2/ to the soil on % Mg in barley were compared in a field experiment on an acid loam to which several rates of limestone had been applied. Treatments had no effect on the % Mg in grain or straw at maturity. At four earlier stages of growth (NH/sub 4/)/sub 2/SO)/sub 4/ increased % Mg in the plants more than did NaNO/sub 2/. Limestone slightly increased % Mg. Nitrification of NH/sub 4/ in the soil was rapid.

Preliminary study of the favorability for uranium in the Madera Limestone, and Cutler and Chinle Formations of the Sierra Nacimiento-Jemez Mountains area, New Mexico

International Nuclear Information System (INIS)

Vizcaino, H.P.; O'Neill, A.J.; Dotterer, F.E.

1978-01-01

Small, surficial, secondary uranium deposits are present in several formations in the Sierra Nacimiento-Jemez Mountains region, but none of significant size are known. Field surveys indicate that the deposits are laterally discontinuous and are, in most cases, associated with carbonaceous debris. Mineral contents of as much as 0.18 percent U 3 O 8 are recorded. There are 2 known deposits in the Pennsylvanian Madera Limestone, 18 in the Permian Cutler Formation, and 3 in the Triassic Chinle Formation. The Madera Limestone consists of a lower and an upper member. The lower member is predominantly a dense limestone and is lithologically unfavorable. The upper member, which consists of several arkosic units interbedded with cherty limestone, is not a favorable host rock because of its thin arkosic units, the paucity of carbonaceous debris, and its lithologically unfavorable limestone. The Cutler Formation consists mostly of interfingering siltstones and fine- to coarse-grained feldspathic and arkosic sandstones of fluvial origin. The sandstones are generally lenticular, average about 40 ft in thickness, and are favorable. Cutler equivalents south of lat 36 0 N. (Abo and Yeso Formations) were not included in this study. The Chinle Formation in the project area consists of five members. The Agua Zarca Member, medium-grained to conglomeratic sandstone with beds that average 30 ft in thickness, is the only unit in the Chinle considered favorable. The stratigraphic units under consideration have been eroded and deformed; beds dip steeply. Upturned and deeply dissected beds afford access to infiltrating waters; oxidation and flushing of pre-existing uranium deposits is therefore suspected. The uranium deposits in the Madera, Cutler, and Chinle are likely to be remnants, and the probability of locating any large deposits within the area is therefore low

Acid mine drainage neutralization in a pilot sequencing batch reactor using limestone from a paper and pulp industry

CSIR Research Space (South Africa)

Vadapalli, VRK

2015-10-01

Full Text Available This study investigated the implications of using two grades of limestone from a paper and pulp industry for neutralization of acid mine drainage (AMD) in a pilot sequencing batch reactor (SBR). In this regard, two grades of calcium carbonate were...

Predicting accurate absolute binding energies in aqueous solution

DEFF Research Database (Denmark)

Jensen, Jan Halborg

2015-01-01

Recent predictions of absolute binding free energies of host-guest complexes in aqueous solution using electronic structure theory have been encouraging for some systems, while other systems remain problematic. In this paper I summarize some of the many factors that could easily contribute 1-3 kcal......-represented by continuum models. While I focus on binding free energies in aqueous solution the approach also applies (with minor adjustments) to any free energy difference such as conformational or reaction free energy differences or activation free energies in any solvent....

Estimation of deep infiltration in unsaturated limestone environments using cave lidar and drip count data

OpenAIRE

Mahmud, K.; Mariethoz, G.; Baker, A.; Treble, P. C.; Markowska, M.; McGuire, E.

2016-01-01

Limestone aeolianites constitute karstic aquifers covering much of the western and southern Australian coastal fringe. They are a key groundwater resource for a range of industries such as winery and tourism, and provide important ecosystem services such as habitat for stygofauna. Moreover, recharge estimation is important for understanding the water cycle, for contaminant transport, for water management, and for stalagmite-based paleoclimate reconstructions. Caves offer a n...

Influence of the environment on weathering of limestone: study through mercury porosimetry

Directory of Open Access Journals (Sweden)

Sánchez Rojas, M. I.

1999-06-01

Full Text Available The physic-chemical processes of decay in building materials and, particularly those affecting petreum materials, obey to different causes as composition, morphology, texture, the orientation of the material in the building and, mainly, its interaction with the environment. Because of their chemical composition, limestone materials may undergo alterations when they are in contact with aggressive media. Rain water or fog contain gases that may dissolve the stone provoking crusts due to salts precipitation. This work is based in the study of the decay processes of a limestone material from a building placed at Madrid. Mercury porosimetry technique (among others is used in this study.

Los procesos físico-químicos de degradación de los materiales de construcción en general, y de los materiales pétreos en particular, obedecen a distintas causas, como son: composición, morfología, textura, orientación en el edificio, y principalmente de la interacción con el medioambiente. Los materiales calizos, por su composición química, pueden sufrir alteraciones al entrar en contacto con un medio agresivo, como puede ser el agua de lluvia o niebla contaminada con gases, que actúan disolviendo la roca y provocando costras por precipitación de sales. Este trabajo tiene como base el estudio de un material calizo, procedente de un edificio situado en una zona céntrica de Madrid, utilizando porosimetría de mercurio, entre otras técnicas instrumentales.

Soluble salt sources in medieval porous limestone sculptures: A multi-isotope (N, O, S) approach

Energy Technology Data Exchange (ETDEWEB)

Kloppmann, W., E-mail: w.kloppmann@brgm.fr [BRGM, Direction des Laboratoires, Unité Isotopes, BP 6009, F-45060 Orléans cedex 2 (France); Rolland, O., E-mail: olivierrolland@wanadoo.fr [Montlouis-sur-Loire (France); Proust, E.; Montech, A.T. [BRGM, Direction des Laboratoires, Unité Isotopes, BP 6009, F-45060 Orléans cedex 2 (France)

2014-02-01

The sources and mechanisms of soluble salt uptake by porous limestone and the associated degradation patterns were investigated for the life-sized 15th century “entombment of Christ” sculpture group located in Pont-à-Mousson, France, using a multi-isotope approach on sulphates (δ{sup 34}S and δ{sup 18}O) and nitrates (δ{sup 15}N and δ{sup 18}O). The sculpture group, near the border of the Moselle River, is within the potential reach of capillary rise from the alluvial aquifer. Chemical analyses show a vertical zonation of soluble salts with a predominance of sulphates in the lower parts of the statues where crumbling and blistering prevail, and higher concentrations of nitrates and chloride in the high parts affected by powdering and efflorescence. Isotope fingerprints of sulphates suggest a triple origin: (1) the lower parts are dominated by capillary rise of dissolved sulphate from the Moselle water with characteristic Keuper evaporite signatures that progressively decreases with height; (2) in the higher parts affected by powdering the impact of atmospheric sulphur becomes detectable; and (3) locally, plaster reparations impact the neighbouring limestone through dissolution and re-precipitation of gypsum. Nitrogen and oxygen isotopes suggest an organic origin of nitrates in all samples. N isotope signatures are compatible with those measured in the alluvial aquifer of the Moselle River further downstream. This indicates contamination by sewage or organic fertilisers. Significant isotopic contrasts are observed between the different degradation features depending on the height and suggest historical changes of nitrate sources. - Highlights: • We use S, N and O isotopes to distinguish salt sources in limestone sculptures. • Vertical zonation of degradation is linked to capillary rise and air pollution. • Sulphate salts in lower parts are derived from river/groundwater. • Sulphate salts in higher parts show signature of air pollution. • Nitrates

Assessing the Sensitivity of Mountain Forests to Site Degradation in the Northern Limestone Alps, Europe

Directory of Open Access Journals (Sweden)

Birgit Reger

2015-05-01

Full Text Available Because of some land-use practices (such as overstocking with wild ungulates, historical clear-cuts for mining, and locally persisting forest pasture, protective forests in the montane vegetation belt of the Northern Limestone Alps are now frequently overaged and poorly structured over large areas. Windthrow and bark beetle infestations have generated disturbance areas in which forests have lost their protective functions. Where unfavorable site conditions hamper regeneration for decades, severe soil loss may ensue. To help prioritize management interventions, we developed a geographic information system-based model for assessing sensitivity to site degradation and applied it to 4 test areas in the Northern Limestone Alps of Austria and Bavaria. The model consists of (1 analysis of site conditions and forest stand structures that could increase sensitivity to degradation, (2 evaluation of the sensitivity of sites and stands, and (3 evaluation and mapping of mountain forests' sensitivity to degradation. Site conditions were modeled using regression algorithms with data on site parameters from pointwise soil and vegetation surveys as responses and areawide geodata on climate, relief, and substrate as predictors. The resulting predictor–response relationships were applied to test areas. Stand structure was detected from airborne laser scanning data. Site and stand parameters were evaluated according to their sensitivity to site degradation. Sensitivities of sites and stands were summarized in intermediate-scale sensitivity maps. High sensitivity was identified in 3 test areas with pure limestone and dolomite as the prevailing sensitivity level. Moderately sensitive forests dominate in the final test area, Grünstein, where the bedrock in some strata contains larger amounts of siliceous components (marl, mudstone, and moraines; degraded and slightly sensitive forests were rare or nonexistent in all 4 test areas. Providing a comprehensive overview

Isotopic labeling for the understanding of the alteration of limestone used in built cultural heritage

Science.gov (United States)

Saheb, Mandana; Chabas, Anne; Mertz, Jean-Didier; Rozenbaum, Olivier; Verney-Carron, Aurélie

2015-04-01

This project belongs to a specific work aiming at developing isotopic tools to better understand the alteration of materials used in the built cultural heritage. It is focused on the study of the alteration of limestone used in the facades of historic buildings subject to atmospheric polluted environment. Actually in the elevated parts of the buildings, water as rainfall (runoff or wet deposition) or in vapor form (condensation or dry deposition) is the main agent of alteration. Thus, the rock/water interactions need to be well understood to propose adapted solution to better preserve the buildings. To identify the water transfer within the porous limestone and locate the reaction preferential sites, two isotopic tracers (D and 18O) are used to monitor the alteration solution (D) and locate the zones containing the secondary phases (18O). The Saint-Maximin limestone used in many monuments in the suburbs of Paris (France) as a building and restoration stone has been specifically studied. Pristine materials, stones from monuments (monuments in the Paris area) and samples altered in laboratory constitute the analytical corpus to compare different stages of alteration. In a first step the stones are characterized at different scales to identify the alteration pattern (SEM-EDS, Raman microspectrometry, XRD, rugosimetry) and study the water transfers (X-ray tomography, mercury porosimetry, imbibition kinetics). The samples are then altered in the laboratory by realistic and controlled wet or dry deposition using isotopically labeled solutions to locate the reaction zones by SIMS. The multiscale characterization of the alteration pattern has allowed proposing alteration mechanisms linked to the properties of the stones and their location inside the building. Moreover, the location of the reactive zones inside the materials determined by the isotopic experiments helps examining the role of the evolution of porosity and formation of alteration products within the material

Electrical conductivity of sandstone, limestone, and granite

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Duba, A.; Piwinskii, A.J.; Santor, M.; Weed, H.C.

1978-01-01

The electrical conductivity of cylindrical cores of Westerly granite, Indiana limestone and Nugget, St Peter and Kayenta sandstones was measured at about 25/sup 0/C in vacuo, in air, and after saturation in distilled water, tap water, and 0.1 M NaCl solution. The three-electrode technique with a guard ring and the two-electrode technique without a guard ring were used. Core aspect ratio over the range of 2.00 to 0.25, as well as frequency over the range of 50 Hz to 10 kHz, influences the conductivity of all rocks, especially those measured in vacuo. Measurements from water-saturated samples using a guard ring are not appreciably different from those obtained without a guard ring. The conductivity of rocks saturated in 0.1 M NaCl solution changes least with a change in aspect ratio; for these rocks a linear relationship, known as Archie's Law, exists between log porosity and log conductivity. No simple correlation was found between those factors in rocks saturated with tap or distilled water. Thus, it appears Archie's Law is of questionable value for correlating laboratory data from rocks saturated with low-conductivity fluids.

Sponge assemblage of some Upper Permian reef limestones from Phrae province (Northern Thailand

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Baba Senowbari-Daryan

1994-12-01

Full Text Available The sponge fauna of uppermost Permian reef or reefal limestones of the Phrae province in northern Thailand include representatives of hexactinellida, sclerospongea,"sphinctozoans", and "inozoans". The "sphinctozoans" and "inozoans"are described in detail. Following taxa are new:"Sphinctozoans": Phraethalamia tubulara n. gen., n. sp., Ambithalamia pérmican. gen., n. sp."Inozoans": Bisiphonella tubulara n. sp., Solutossaspongia crassimuralis n.gen., n. sp.The genus name Belyaevaspongia nom. nov. is proposed for PolysiphonellaBelyaeva, 1991 (in Boiko et al., 1991, non Polysiphonella Russo, 1981.

Chiritopsis longzhouensis, a New Species of Gesneriaceae from Limestone Areas in Guangxi, China

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Bo Pan

2010-11-01

Full Text Available A new species of Gesneriaceae, Chiritopsis longzhouensis B. Pan & W. H. Wu from limestone areas in Guangxi, China, is described and illustrated. The new species is similar to C. jingxiensis Yan Liu, W. B. Xu & H. S. Gao in the corolla shape, but differs in its leaf blade 2-4 × 1.3-2.5 cm, appressed pilose on both surfaces, Cymes 5-10, 1-3-branched, each 5-25-flowered, filaments geniculate about 1 mm above base, sparsely glandular-puberulent, staminodes 3.

Neutron radiography and X-ray computed tomography for quantifying weathering and water uptake processes inside porous limestone used as building material

International Nuclear Information System (INIS)

Dewanckele, J.; De Kock, T.; Fronteau, G.; Derluyn, H.; Vontobel, P.; Dierick, M.; Van Hoorebeke, L.; Jacobs, P.; Cnudde, V.

2014-01-01

Euville and Savonnières limestones were weathered by acid test and this resulted in the formation of a gypsum crust. In order to characterize the crystallization pattern and the evolution of the pore structure below the crust, a combination of high resolution X-ray computed tomography and SEM–EDS was used. A time lapse sequence of the changing pore structure in both stones was obtained and afterwards quantified by using image analysis. The difference in weathering of both stones by the same process could be explained by the underlying microstructure and texture. Because water and moisture play a crucial role in the weathering processes, water uptake in weathered and non-weathered samples was characterized based on neutron radiography. In this way the water uptake was both visualized and quantified in function of the height of the sample and in function of time. In general, the formation of a gypsum crust on limestone slows down the initial water uptake in the materials. - Highlights: • Time lapse sequence in 3D of changing pore structures inside limestone • A combination of X-ray CT, SEM and neutron radiography was used. • Quantification of water content in function of time, height and weathering • Characterization of weathering processes due to gypsum crystallization

Synthesis of Calcite Nano Particles from Natural Limestone assisted with Ultrasonic Technique

Science.gov (United States)

Handayani, M.; Sulistiyono, E.; Firdiyono, F.; Fajariani, E. N.

2018-03-01

This article represents a precipitation method assisted with ultrasonic process to synthesize precipitated calcium carbonate nano particles from natural limestone. The synthesis of nanoparticles material of precipitated calcium carbonate from commercial calcium carbonate was done for comparison. The process was performed using ultrasonic waves at optimum condition, that is, at temperature of 80oC for 10 minutes with various amplitudes. Synthesized precipitated calcium carbonate nanoparticles were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Particle Size Analyzer (PSA). The result of PSA measurements showed that precipitated calcium carbonate nano particles was obtained with the average size of 109 nm.

Environmental risk evaluation of the use of mine spoils and treated sewage sludge in the ecological restoration of limestone quarries

Science.gov (United States)

Jordán, M. M.; Pina, S.; García-Orenes, F.; Almendro-Candel, M. B.; García-Sánchez, E.

2008-07-01

The ecologic restoration criteria in areas degraded from extraction activities require making use of their mine spoils. These materials do not meet fertility conditions to guarantee restoration success and therefore, need the incorporation of organic amendments to obtain efficient substratum. Reducing the deficiencies in the organic material and restoration material nutrients with the contribution of treated sewage sludge is proposed in this work. This experiment was based on a controlled study using columns. The work was conducted with two mine spoils, both very rich in calcium carbonate. The first mineral, of poor quality, came from the formation of aggregates of crushed limestone ( Z). The other residual material examined originated in limestone extraction, formed by the levels of interspersed non-limestone materials and the remains of stripped soils ( D). Two treatments were undertaken (30,000 and 90,000 kg/ha of sewage sludge), in addition to a control treatment. The water contribution was carried out with a device that simulated either short-duration rain or a flooding irrigation system in order to cover the surface and then percolate through the soil. The collection of leached water took place 24 h after the applications. Different parameters of the leached water were determined, including pH, electrical conductivity, nitrate anions, ammonium, phosphates, sulphates and chlorides. The values obtained for each irrigation application are discussed, and the nitrate values obtained were very elevated.

A rapid and accurate approach for prediction of interactomes from co-elution data (PrInCE).