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Letteratura scientifica selezionata sul tema "Limestone addition"

Autore: Grafiati

Pubblicato: 10 ottobre 2023

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Articoli di riviste sul tema "Limestone addition"

Gołaszewski, J., G. Cygan e M. Gołaszewska. "Analysis of the Effect of Various Types of Limestone as a Main Constituent of Cement on the Chosen Properties of Cement Pastes and Mortars". Archives of Civil Engineering 65, n. 3 (1 settembre 2019): 75–86. http://dx.doi.org/10.2478/ace-2019-0035.

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AbstractThe article is an attempt to compare the impact of the use of various types of limestone as the main constituent of cement on selected mortar properties. Four different limestones were added in amount of 15, 30, 40% to CEM I 42.5 R to obtain limestone cemens. Rheological properties (yield stress, plastic viscosity) of fresh mortar, tensile and compressive mortar strength, early shrinkage, and drying shrinkage were tested. Obtained results indicate that both tensile and compressive strength decreases with the increase of the limestone content in cement. Limestone can worsen or improve workability, depending on distribution of limestone grains. The addition of limestone increases the early shrinkage, but reduces the shrinkage after 28 days. Studies show that the granulation of limestone plays an important role in determining the influence of limestone on mortar properties.

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Chen, Chun Tao, Jiang Jhy Chang, Wei Chung Yeih e Shun Ting Chang. "Sustainable Performance of Limestone Cement". Advanced Materials Research 476-478 (febbraio 2012): 1692–96. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.1692.

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This study explores the effects of the limestone addition on the mechanical properties and durability of the cement. Portions of the Portland cements were replaced by the limestone powders. Results showed that the compressive strengths of the mortar were reduced by the limestone addition. In general, the addition of limestone helps to reduce the shrinkage and improve the sulfate attack resistance. The lowest sulfate-expansion occurred at the specimens with a limestone addition of 10%. Moreover, with additions of 10% or less, the reductions in strength were likely recovered by the addition of fly ash.

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Elgalhud, Abdurrahman A., Ravindra K. Dhir e Gurmel Ghataora. "Limestone addition effects on concrete porosity". Cement and Concrete Composites 72 (settembre 2016): 222–34. http://dx.doi.org/10.1016/j.cemconcomp.2016.06.006.

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Wasis, Basuki, e Eranissa Islamika. "Pengaruh Penambahan Arang Tempurung Kelapa dan Bokashi Pupuk Kandang Terhadap Pertumbuhan Semai Akasia (Acacia Mangium Willd.) di Media Bekas Tambang Kapur". Journal of Tropical Silviculture 10, n. 1 (14 agosto 2019): 29–34. http://dx.doi.org/10.29244/j-siltrop.10.1.29-34.

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Continuous mining activities of limestone operation may cause negative impact such as environmental damage and reduction of soil quality (physically, chemistry, or biological). Revegetation is the process to increasing productivity of postmining limestose land. Acacia mangium is one of fast growing species that can grow in marginal land, symbitotic with rhizobium bacteria, and high economic value. The purpose of this research are to test the response of coconut shell charcoal and cow feces (bokashi) addition to the growth of akasia (Acacia mangium) seedling on postmining limestone soil and to find out the optimum dose of coconut shell charcoal and cow feces (bokashi) addition. This research used a complete randomized design factorial with two factors, each factor have four degree. First factor is addition of coconut shell charcoal and second factors is addition of cow feces (bokashi). The result of this research showed that coconut shell charcoal and cow feces (bokashi) addition on postmining limestone soil gives positive influence towards the amount of root nodule. But not affect other parameters such as height, diameter, total wet weight, total dry weight, and root tops ratio. The interaction between addition 10 g of coconut shell charcoal and 20 g of cow feces (bokashi) is the best composition for a significant effect in improving the amount of root nodule of A. mangium seedling by 78.58%. Very high levels of Ca in the soil medium will be toxic to the acacia plant.Keywords: Acacia mangium, bokashi cow feces, coconut shell charcoal, limestone mining

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Elgalhud, Abdurrahman A., Ravindra K. Dhir e Gurmel S. Ghataora. "Carbonation resistance of concrete: limestone addition effect". Magazine of Concrete Research 69, n. 2 (gennaio 2017): 84–106. http://dx.doi.org/10.1680/jmacr.16.00371.

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Elgalhud, Abdurrahman A., Ravindra K. Dhir e Gurmel Ghataora. "Chloride ingress in concrete: limestone addition effects". Magazine of Concrete Research 70, n. 6 (marzo 2018): 292–313. http://dx.doi.org/10.1680/jmacr.17.00177.

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Jensen, Anker, Jan Erik Johnsson e Kim Dam-Johansen. "Nitrogen chemistry in FBC with limestone addition". Symposium (International) on Combustion 26, n. 2 (1996): 3335–42. http://dx.doi.org/10.1016/s0082-0784(96)80181-0.

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Danny, Gunaran, Nasus K. Y., Josep P. F. Napitupulu e Amelia Makmur. "The Influence of Limestone And Calcium Hydroxide Addition in Asphalt Concrete Mixture". ComTech: Computer, Mathematics and Engineering Applications 7, n. 2 (1 giugno 2016): 83. http://dx.doi.org/10.21512/comtech.v7i2.2242.

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As time passes, flood often occurs in the area of Gunung Sahari, Jakarta Utara. The flood damages concrete asphalt mixture and it needs particular improvement. Therefore, the purpose of this research is to know the effects of the added combination of limestone and calcium hydroxide on concrete asphalt mixture as a filler resistant to flood. Concrete asphalt mixture that filled with the combination of limestone and calcium hydroxide is a mixture that is made with non-uniform aggregat gradations, filler and liquid asphalt mixed and solidified in a heat state. Limestone and calcium hydroxide mixture is used because both materials included in the most numerous sedimentary rock. Concrete asphalt mixture with the filler combination of limestone and calciumhydroxide is made with optimum asphalt 5.4%, one variation level of limestone (15%), and calcium hydroxide (15%), and three variation levels of fillers (5%, 7.5%, and 15%) to get optimum asphalt levels and filler levels that are compatible with flood condition. Based on optimum asphalt 5.4% towards aggregate total weight and combined level of limestone and calcium hydroxide suitable for the conditions, 8.75 % towards fine aggregate weight. The characteristic value of limestone and calcium hydroxide mixture in maximum condition is VIM 4.55%, VMA 18.83%, stability 1031.26 kg and flow 4.93 mm, where the characteristic value meets the established specifications standard by Pekerjaan Umum Bina Marga. From the result, it is showed that the use of the mixture can decrease the value of stability and increase the value of flow, compared with asphalt and filler with normal levels.

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Thalmaier, Gyorgy, Nicoleta Cobȋrzan, Anca-Andreea Balog, Horia Constantinescu, Andrei Ceclan, Mirela Voinea e Traian Florin Marinca. "Assessment of Limestone Waste Addition for Fired Clay Bricks". Materials 15, n. 12 (16 giugno 2022): 4263. http://dx.doi.org/10.3390/ma15124263.

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Our aim was to investigate the feasibility of using limestone waste resulting from stone processing for the manufacturing of fired clay bricks. Waste materials were considered as a partial replacement for clays to reduce the exploitation of natural resources and as a response to the climate neutrality commitments. The samples were prepared to have a waste content of up to 15% and were fired at a temperature of 900 °C. The chemical and mineralogical composition and the physical analysis of raw materials were investigated by using SEM–EDS and XRD diffraction. The result showed an increase in CaO in the clay mixture due to the presence of limestone, which reduced the shrinkage of the products’ compressive strength, up to 55% for samples with a higher content of limestone (15 wt.%), and influenced the samples’ color by making them lighter than the reference sample.

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Ahmad, Muhammad, Muhammad Sajjad, Irfan Khan, Amina Durrani, Ali Durrani, Saeed Gul e Asmat Ullah. "Sustainable production of blended cement in Pakistan through addition of natural pozzolana". Chemical Industry and Chemical Engineering Quarterly 22, n. 1 (2016): 41–45. http://dx.doi.org/10.2298/ciceq141012017a.

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In this work pozzolana deposits of district Swabi, Pakistan were investigated for partial substitution of Portland cement along with limestone filler. The cement samples were mixed in different proportions and tested for compressive strength at 7 and 28 days. The strength activity index (SAI) for 10 % pozzolana, and 5% limestone blend at 7 and 28 days was 75.5% and 85.0% satisfying the minimum SAI limit of ASTM C618. Twenty two percents natural pozzolana and five percents limestone were interground with clinker and gypsum in a laboratory ball mill to compare the power consumption with ordinary Portland cement (OPC) (95% clinker and 5% gypsum). The ternary blended cement took less time to reach to the same fineness level as OPC due to soft pozzolana and high grade lime stone indicating that intergrinding may reduce overall power consumption. Blended cement production using natural pozzolana and limestone may reduce the energy consumption and green house gas emissions.

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Più fonti

Tesi sul tema "Limestone addition"

Akpulat, Onur. "Co-combustion Of Coal And Olive Cake In A Fluidized Bed With Limestone Addition And Freeboard Extension". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611160/index.pdf.

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In this study, flue gas emissions and combustion efficiencies during combustion and co-combustion of olive cake and coal are investigated in a bubbling fluidized bed with an inside diameter of 102 mm and a height of 900 mm and 1900 mm. Tunç
bilek lignite coal and Edremit olive cake were used in the experiments as fuels. Temperature distributions along the combustion column were continuously measured. Flue gas concentrations of O2, CO, SO2 and NOx were measured during combustion experiments. Four sets of experiments were performed in order to examine the effect of fuel composition, excess air ratio, freeboard extension and limestone addition on flue gas emissions and combustion efficiency. The olive cake addition to coal were 25, 50, 75 % by wt. The bed temperature on the average was 850 oC. The results of the experiments showed that coal combustion occurs at lower parts of the combustion column whereas olive cake combustion takes place more in the freeboard region. As olive cake percentage in the fuel mixture increased, CO emissions increased, SO2 and NOx emissions decreased. The reason for the decrease of NOx emissions with increasing percentage of olive cake in the fuel mixture was due to a reducing atmosphere created in the combustion column. Mostly combustion losses resulted mainly from the unburnt carbon in the fly ash. With the freeboard extension, noticeable decrease in CO emissions and slight increase in combustion efficiencies were observed. Among the limestones tested, Ç
an limestone gave the best result with Ca/S = 3 at an optimum bed temperature of 850 oC. The SO2 reduction was 87% at this Ca/S ratio. For co-combustion experiments, it was observed that SO2 adsorption efficiency of limestone increased with the addition of olive cake to the fuel mixture.

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Elmakki, Rihab Abdelrahman Mohamed. "The effect of extending four cements with limestone with addition of super-plasticisers on the hydration reaction of SCC cement paste". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2466.

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Thesis (MTech (Civil Engineering))--Cape Peninsula University of Technology, 2016.
The addition of certain fillers and additives in conventional concrete is imperative for improving its rheological properties. The effect of additives, namely limestone (LS) and superplasticisers (SP), on the hydration kinetics of self-compacting concrete (SCC) was investigated on cement paste scale. These additives interact mostly with cement paste, since aggregates are considered to be inert materials. An understanding of the effect of these additives on the hydration kinetics of cement paste is paramount to the design of an SCC with excellent properties. Four CEM I 52.5N Portland cements from one supplier but produced at different factories, LS and two types of SP, were used in this research. The hydration kinetics were evaluated by monitoring the elastic modulus growth of the cement pastes. Different coefficients of the self-acceleration kinetics equation – the self-acceleration constant, characteristic time and real time of hydration – were used to establish the effect of different concentrations of SP with and without the optimum concentration of limestone (30%) on the hydration kinetics of cement pastes. As far as can be ascertained, this is the first time the rheokinetic model has been used to describe the initial hydration of SCC paste.

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Mosser, Lucas. "Formulation de bétons décarbonés à base de clinker, métakaolin et d’addition calcaire pour une application aux produits préfabriqués". Electronic Thesis or Diss., IMT Mines Alès, 2023. http://www.theses.fr/2023EMAL0004.

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L’objectif des travaux rapportés dans ce mémoire de thèse est la formulation de solutions à faible empreinte carbone (< 150 kg.éq.CO2/m3) et industriellement viables. En premier lieu, la substitution d’une forte teneur en clinker (65 % à 70 %) par du métakaolin et des additions calcaires est étudiée. Ensuite, l’optimum de compacité du squelette granulaire (via le Modèle d’Empilement Compressible) a été recherché pour minimiser le volume de pâte requis.L’application de leviers matériau (faible teneur en eau et adjuvantation) et procédés (traitement thermique) a permis d’approcher les performances d’une référence à base de ciment Portland. Une résistance à la compression supérieure à 14 MPa à 8 heures et des classes de résistance à 28 jours C25/30 et C40/50 ont été atteintes. Via l’approche performantielle, les classes de durabilité XC2 ou XC4, XS3e et XS3m ont pu être validées. Ces solutions décarbonées ont permis la fabrication de prémurs à l’échelle industrielle
The aim of the presented research is to formulate industrially viable low carbon footprint concrete (< 150 kg.eq.CO2/m³). First, high substitution of clinker (65 % to 70 %) by metakaolin and limestone has been investigated to reduce the concrete’s carbon footprint. Then, granular packing compacity has been optimized with the Compressible Packing Model to reduce the required paste volume.High water content reduction (with adapted admixture content) and a thermal treatment have been applied to approach an Ordinary Portland Cement concrete’s performances. Compressive strength of superior to 14 MPa at 8 hours and strength classes of C25/30 and C40/50 have been reached. Also, through a performance approach, durability classes XC2 or XC4, XS3e and XS3m have been validated. The developed low carbon solutions were used to produce walls with integrated formwork at the industrial scale

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Riggs, Katherine Sarah. "Soil chemical changes following limestone additions to acid soils". Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315889.

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Skriňáková, Eva. "Optimalizace složení betonů s využitím plniv z recyklovaných betonů". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240222.

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Concrete as a building material is subject to continuous innovation and thanks to advanced technology and quantum of research, its properties are still improved. It is logical that the more concrete we produce, the more waste it arises. The volume of this waste can not be stored in landfills endlessly, nowadays most of the waste economies in the world are trying to recycle concrete rubble. The recycling is not such a problem, the technology has been long verified but the quality of the recycled concrete aggregate is unquestionably one of the primary assumption which leads to accomplish required properties of concrete. In fact, the recycling process is „crushing“ the concrete into particles with an effort to eliminate the cement paste on the surface of the aggregate. An ideal solution would be create a resistant and firm coating that would adhere perfectly to the cement matrix. This diploma thesis is focused on the properties of recycled concrete aggregate and methods of improvement and optimization of the concrete mix composition.

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Eberhart, Ryan J. "Characterization of a highly acid watershed located mainly in Perry County, Ohio". Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1176834923.

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Khokhar, Muhammad Irfan. "Optimisation of concrete mix design with high content of mineral additions: effect on microstructure, hydration and shrinkage". Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209985.

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The cement being used in the construction industry is the result of a chemical process

linked to the decarbonation of limestone conducted at high temperature and results in a

significant release of CO2. This thesis is part of the project EcoBéton (Green concrete) funded

by the French National Research Agency (ANR), with a purpose to show the feasibility of

high substitution of cement by mineral additions such as blast furnaces slag, fly ash and

limestone fillers. Generally for high percentages of replacements, the early age strength is

lower than Portland cement concrete. To cope with this problem, an optimisation method for

mix design of concrete using Bolomey’s law has been proposed. Following the encouraging

results obtained from mortar, a series of tests on concretes with different substitution

percentages were carried out to validate the optimisation method. To meet the requirements of

the construction industry related to performance of concrete at early age, which determine

their durability, a complete experimental study was carried out. Standard tests for the

characterization of the mechanical properties (compressive strength, tensile strength, and

setting) allowed to validate the choice of mix design on the basis of equivalent performance.

We focused on the hydration process to understand the evolution of the mechanical

properties. Setting time measurement by ultrasound device at different temperatures (10°C,

20°C and 30°C) showed that ground granulated blast furnace slag (GGBFS) and fly ash

delayed the setting process, while use of limestone filler may accelerate this process.

Calorimetric studies over mortars and concretes made possible to calculate the activation

energy of the different mixtures and a decrease in heat of hydration of concretes with mineral

additions was observed which is beneficial for use in mega projects of concrete. Scanning

Electron Microscopy observations and thermal analysis have given enough information about

the hydration process. It was observed that the hydration products are similar for different

concrete mixtures, but the time of their appearance and quantity in the cement matrix varies

for each concrete mix.

Last part of the thesis was dedicated to the study of main types of shrinkage. First of all,

deformations measured were correlated to hydration, capillary depression and porosity

evolution. Results allowed concluding that the use of mineral additions has an actual effect on

the plastic shrinkage behaviour, but its impact is not proportional to the percentage of

additions. Substitution of cement by the additions seems to have a marked influence on the

kinetics of the shrinkage without any effect on its long term amplitude. The study of

restrained shrinkage under drying conditions by means of ring tests showed that concretes

with high percentage of slag addition seem more prone to cracking than the Portland cement

concretes.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

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Gillmor, Anna M. "Attenuation of Acid Mine Drainage Enhanced by Organic Carbon and Limestone Addition: A Process Characterization". 2011. https://scholarworks.umass.edu/theses/609.

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Surface and groundwaters in contact with mining-exposed pyritic materials have the capacity to generate acid mine drainage (AMD), an acidic, sulfate-rich, metals-laden effluent. The Davis Mine located in northwestern Massachusetts offers a model site to study the processes of natural attenuation of acid mine drainage. These include physico-chemical processes such as dilution and sorption, geochemical processes such as aluminosilicate weathering and biological processes such as transformation and cycling of sulfate, iron and acidity by bacterial metabolism. A focus of recent research undertaken at the site has been characterizing the presence and activity of these bacteria with an aim to stimulate their capacity to attenuate the severity of acidic conditions. To further this investigation, a pilot-scale treatment system was installed, composed of a modified permeable reactive barrier containing organic carbon and limestone. Down-gradient groundwater was sampled over a sixteen-month period for concentrations of dissolved metals, major cations and sulfate, along with pH and redox measurements. The results showed a decrease in dissolved metals, a possible increase in calcium and decrease in sulfate, and measurable increase in pH and corresponding decrease in oxidation-reduction potential. Major decreases in dissolved iron and aluminum were observed, a change which is not entirely consistent with metals removal by combination with biogenic sulfide alone. The additional influence of hydrolysis was proposed and the anticipated action of this alternate process found to bear resemblance to the observed changes. Groundwater composition from the experimental period was compared to previous measurements and significant changes described in pH, iron, aluminum, copper and zinc and to a lesser extent in calcium and sulfate. Comparisons were also made with concurrent surface water compositions and findings of analogous studies. Conclusions that can be drawn include: the pH and redox environment into which a treatment system is placed can greatly influence the reactions which take place, side-reactions which occur in reducing and alkalinity-generating amendments may also have an attenuating effect, and variable processes influence groundwater composition in these biogeochemically complex environments.

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Libri sul tema "Limestone addition"

Zijlma, Geuchien Jan. Effect of air staging and limestone addition on emmissions of SO2 and NOx in circulating fluidized bed combustion: Proefschrift. Veenendaal: Universal Press, 2002.

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Phillips, J. M. Yield, quality and nitrogen recovery of coastal bermudagrass as affected by limestone rates and sulfur-magnesium fertilizer additions. Fayetteville, Ark: Arkansas Agricultural Experiment Station, 1995.

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Geological Survey (U.S.), a cura di. Fracture history of the Redwall Limestone, lower Supai Group, and Tertiary units on the Hualapai Indian Reservation, northwestern Arizona: Additional data to open-file report 87-359. [Denver, Colo.?]: U.S. Dept. of the Interior, Geological Survey, 1989.

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Huang, Chang-Chih. A microchemical analysis of the reactivities of two types of limestone based sorbents from New York State with reagent form hematite additive in desulfurization process under atmospheric fluidized bed combustion condition. 1995.

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Series, Michigan Historical Reprint. On the Laurentian limestones of North America, by T. Sterry Hunt ... Reprinted with additions from the Report of the Geological survey of Canada for 186366. Scholarly Publishing Office, University of Michigan Library, 2005.

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Fracture history of the Redwall Limestone, lower Supai Group, and Tertiary units on the Hualapai Indian Reservation, northwestern Arizona: Additional data to open-file report 87-359. [Denver, Colo.?]: U.S. Dept. of the Interior, Geological Survey, 1989.

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Skupio, Rafał. Zastosowanie nieinwazyjnych pomiarów rdzeni wiertniczych do zwiększenia informacji na temat parametrów skał zbiornikowych. Instytut Nafty i Gazu - Państwowy Instytut Badawczy, 2022. http://dx.doi.org/10.18668/pn2022.237.

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The research carried out in the monograph aimed to create a measurement and interpretation system which is to obtain reliable results of well logging with the accuracy of laboratory measurements. Continuous core measurements allow for the generation of logging results without the impact of the borehole and facilitate the depth matching of the core to well log data. Four main chapters can be distinguished in this work: research methodology with a description of the devices used; partial results of core measurements made on various types of rocks; a proposal for a research system, and comprehensive data interpretation for selected boreholes. The methodological part concerned the description of the equipment for continuous measurements of cores in the field of natural gamma radioactivity (K, U, Th) with the application for bulk density measurements using the gamma-gamma method, X-ray fl uorescence spectrometers (XRF) for measuring the chemical composition of rocks and computed tomography (CT) for imaging of the core structure as well as determination of radiological density in Hounsfi eld units (HU). Rock studies were carried out on material representing formations of diff erent lithologies, such as shales, sandstones, limestones, dolomites, anhydrite, siltstones and heterolithic sandstone-siltstone-claystone complexes. The results of measurements made using individual methods have been described in detail and compared with the results of laboratory measurements and well logging data. Test measurements with data processing and interpretation were made on the cores from five boreholes (T-1, O-4, Pt-1, L-7, P-5H), whereas a comprehensive interpretation of the results was carried out for three other boreholes (J-1, P-4, T-2). The new methodology of spectral gamma measurements made it possible to obtain precise concentrations of potassium, uranium and thorium in rocks with high and low radioactivity. The results made it possible to standardise the archival gamma-ray logs made with the Russian-type probes from imp/min to API standard units and to obtain data on the content of K, U, and Th in the core intervals. Using the Cs-137 source in the device for the gamma equipment made it possible to carry out measurements of the bulk density in g/cm3 units. The lithological interpretation based on XRF measurements and mineralogical-chemical models allowed to obtain logs with increased resolution and a more signifi cant number of minerals than was the case with the interpretation of the well logging. In addition, it has been shown that the XRF measurement methodology can be used during the geosteering procedure. The results of the core tests using the CT computed tomography method were presented in combined images and continuous curves of density in HU units. The experience and the presentation of the full scope of measurement and interpretation workflow allowed to propose a procedure for conducting a full range of analyses, considering various types of material provided for research. The procedure considers the full range of analyses as well as the measurements of selected parameters depending on the client’s needs. Keywords: petrophysics, core analyses, XRF spectrometry, computed tomography, gamma profiling, lithological interpretation

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Capitoli di libri sul tema "Limestone addition"

Rangeard, Damien, Arnaud Perrot e Malalasoa Rodomond. "Effect of Limestone Powder Addition Quality on SCC Rheology". In RILEM Bookseries, 500–507. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22566-7_58.

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Cura, Dania Betancourt, e Jose Fernando Martirena-Hernandez. "Assessment of Addition of Calcinated Clay-Limestone-Plaster to Ordinary Portland Cement in Brickwork Mortars". In RILEM Bookseries, 211–15. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22034-1_24.

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Díaz García, María B., Lyannis Aparicio Ruíz e Jose Fernando Martirena-Hernandez. "Effect of the Addition of Calcined Clay-Limestone-Gypsum in the Hydration of Portland Cement Pastes". In RILEM Bookseries, 23–29. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22034-1_3.

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Adams, Timothy B., e Robert W. Brocksen. "Dose-Response Relationships for the Addition of Limestone to Lakes and Ponds in the Northeastern United States". In Restoration of Aquatic and Terrestrial Systems, 137–63. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2279-2_10.

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Vargas, Juan Francisco Garcés, Flavio Morocho Guamán, Yosvany Diaz Cárdenas, Alina Hereira Diaz e Jose Fernando Martirena-Hernandez. "Production of Durable Concrete with a Mineral Addition Blend of Calcined Clay-Limestone-Gypsum (LC2) and Portland Cement". In RILEM Bookseries, 183–93. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22034-1_21.

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Thornton, E. Lexus, Avery Hartley, Daniel Caudill, Martin Gamesu, Julius Schoop e Fazleena Badurdeen. "Evaluating the Sustainability of Paper and Plastic Substitute Material LimeX". In Lecture Notes in Mechanical Engineering, 1082–90. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-28839-5_120.

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AbstractWith the increasing decline in the environment and natural resources it is important to find new ways in which manufacturing can increase the sustainability of the world. This study seeks to compare LimeX, a state-of-the-art paper and plastic alternative primarily made of limestone, with conventional paper and plastic materials. For a better understanding of LimeX as a material, a brief investigation of the mechanical and chemical properties will be performed through experimentation and analysis. In addition, this paper aims to evaluate the sustainability of LimeX through the analysis of metrics relating to the triple bottom line (environmental impacts, economic impacts and societal impacts) to evaluate and compare the sustainability performance of LimeX products with conventional paper and plastic products. The previously developed Product Sustainability Index (ProdSI) will be adapted and used in this study to conduct the sustainability evaluation. Major findings will include results from an experimental analysis of LimeX via SEM and EDS, and LimeX material property measurements via tensile testing and density measurements. In addition, there will also be a comparison of the sustainability performance of conventional paper and LimeX using a simplified ProdSI. The study found that LimeX was marginally more sustainable than paper, but this evaluation could change with information from the development of a life-cycle analysis report on the material.

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Çakoğlu, Arif Hikmet. "Evaluation of Natural Stones in Different Usage Areas, Samsun Example". In Versatile Approaches to Engineering and Applied Sciences: Materials and Methods. Özgür Yayınları, 2023. http://dx.doi.org/10.58830/ozgur.pub50.c50.

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In Samsun, which is located in the Central Black Sea Region and the largest city of the entire Black Sea Region, the purchase of materials from the quarries, especially limestone, has started as a result of the prohibition of purchasing aggregates from the Yeşilırmak and Kızılırmak basins, especially due to the very low sediment transport. Although the materials taken from the limestone quarries are mostly used in the production of concrete, there are rocks of volcanic origin such as basalt, granite, andesite and, albeit in small numbers, diorite. Limestone quarries, especially concentrated in Kavak district, are widespread in the entire Black Sea Region. In addition, other natural stone quarries used for different purposes other than concrete production are also used in commercial activities. The fact that natural stones have different properties also affects the variety of usage areas. To give an example, while there are companies in our country that can manufacture thermal insulation materials such as rock wool by melting basalt stone at high temperature, no such study has yet been carried out for the existing basalt quarries throughout the province in Samsun. It is thought that the high water absorption capacity of basalt, as in the Ayvacık example, is an important factor in this. However, the same natural stone can be used as ballast material under railway tracks. Samsun has a good potential in terms of the number of reserves and quarries of natural stones used in construction and visual production items in the construction sector, and a significant contribution will be made if new production areas are opened in addition to the existing areas of use.

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Howard, Alan G. "The acidity of water". In Aquatic Environmental Chemistry. Oxford University Press, 1998. http://dx.doi.org/10.1093/hesc/9780198502838.003.0003.

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This chapter examines the acidity of natural water, which depends on the nature of material dissolved in it and its interaction with other materials such as the rocks, the organisms living in it, and added pollutants. Rivers and lakes in granite areas, for example, are unable to neutralize any added acidity and are therefore highly susceptible to the effects of acid rain. Significant increases in the acidity of these water bodies produces an environment which is not well suited to life for a number of reasons. Firstly, most organisms are not well adapted to acidic conditions or changes in acidity. In addition, acidification leads to the dissolution of a number of toxic elements which can poison flora and fauna. In limestone areas, however, the water can neutralize moderate quantities of added acid. The chapter then considers the chemical nature of water, before studying polyprotic acids and the solubility of gases.

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Herz, Norman, e Ervan G. Garrison. "Archaeological Materials :Rocks and Minerals". In Geological Methods for Archaeology. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780195090246.003.0016.

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This chapter is only a brief introduction to lithic archaeological materials. Archaeologists with but little knowledge of rocks and rock-forming minerals are urged to learn about them in greater detail than that presented here. Lithic resources are abundant in almost every archaeological site, and lithic artifacts are invariably the best preserved of any remains. Early societies learned how to exploit these resources, and the use and production of lithics go back to the earliest known sites, at least 1.5 million years. In fact, the earliest cultures are distinguished on the basis of their lithic industries and lithic artifacts. Horror stories in misidentification of lithics abound. Not only have misidentified artifacts proven embarrassing to the archaeologist, but also they have made it difficult to make meaningful comparisons of different societies using published descriptions. In addition, conservation strategies for historical monuments cannot be developed without an understanding of the nature of the material used in their construction. Some egregious examples of ignorance of the rocks and minerals from our personal experience include the following: 1. An archaeologist asked if a quartzite scraper was either flint or chert. When told that it was neither, he asked, "Well then, which is it more like?" (answer, still neither). 2. Egyptian basalt statues have been called limestone in publications (and several other rock types). 3. Sources for alabaster were searched to explain a trading link between a site and elsewhere when the geological map showed the site was adjacent to a mountain of gypsum, the mineral component of alabaster (the gypsum may have merely rolled down the hillside to the workshops, where it became the more salable alabaster). 4. Conservators searched for methods to preserve an allegedly granitic historic monument, or so it had been identified. Chemical analysis revealed only abundant Ca, Mg, and carbonate. Fossils were also abundant in the "granite," which dissolved easily in hydrochloric acid (the "granite" was clearly limestone). Petrology is the branch of geology that deals with the occurrence, origin, and history of rocks. Petrography is concerned with descriptions of rocks, their mineralogy, structures, and textures.

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Migon, Piotr. "Slope Development in Granite Terrains". In Granite Landscapes of the World. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780199273683.003.0013.

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Rock slopes developed in granite may take different forms, as reflected in their longitudinal profiles. Field observations and a literature survey (e.g. Dumanowski, 1964; Young, 1972) allow us to distinguish at least five major categories of slopes: straight, convex-upward, concave, stepped, and vertical rock walls. In addition, overhang slopes may occur, but their height is seldom more than 10 m high and their occurrence is very localized. These basic categories may combine to form compound slopes, for example convex-upward in the upper part and vertical towards the footslope. Somewhat different is Young’s (1972) attempt to identify most common morphologies of granite slopes. He lists six major categories: (1) bare rock domes, smoothly rounded or faceted; (2) steep and irregular bare rock slopes of castellated residual hills, tending towards rectangular forms; (3) concave slopes crowned by a free face; (4) downslope succession of free face, boulder-covered section and pediment; (5) roughly straight or concave slopes, but having irregular, stepped microrelief; (6) smooth convex-concave profile with a continuous regolith cover. The latter, lacking any outcrops of sound bedrock, are not considered as rock slopes for the purposes of this section. Young (1972) appears to seek explanation of this variety in climatic differences between regions, claiming that ‘Variations of slope form associated with climatic differences are as great as or greater, on both granite and limestone, than the similarity of form arising from lithology’ (Young, 1972: 219). This is a debatable statement and apparently contradicted by numerous field examples of co-existence of different forms in relatively small areas. Slope forms do not appear specifically subordinate to larger landforms but occur in different local and regional geomorphic settings. For example, the slopes of the Tenaya Creek valley in the Yosemite National Park include, in different sections of the valley, straight, vertical, convex-upward, and concave variants (Plate 5.1). Apparently, multiple glaciation was unable to give the valley a uniform cross-sectional shape.

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Atti di convegni sul tema "Limestone addition"

Siregar, Amir Hamzah, Saharman Gea e Nora Indriani. "Making Composites from Mixing Limestone with Addition of Latex". In International Conference on Chemical Science and Technology Innovation. SCITEPRESS - Science and Technology Publications, 2019. http://dx.doi.org/10.5220/0008864001650173.

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Kurdowski, W. "Can addition of limestone eliminate the expansion of the mortars due to DEF ?" In International RILEM Workshop on Internal Sulfate Attack and Delayed Ettringite Formation. RILEM Publications SARL, 2004. http://dx.doi.org/10.1617/2912143802.016.

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Selc¸uk, Nevin, Yusuf Gogebakan e Zuhal Gogebakan. "Partitioning of Trace Elements During Fluidized Bed Combustion of High Ash Content Lignite". In 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78068.

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The behavior of 20 trace elements (As, B, Ba, Cd, Co, Cr, Cu, Hg, Li, Mn, Mo, Ni, P, Pb, Sb, Se, Sn, Tl, V, Zn) and 8 major and minor elements (Al, Ca, Fe, K, Mg, Na, Si, Ti) during the combustion of high ash content lignite with and without limestone addition have been investigated in the 0.3 MWt Middle East Technical University (METU) Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) Test Rig. Experiments were performed without fines recycle. Inert bed material utilized in the experiments was bed ash obtained previously from the combustion of the same lignite without limestone addition in the same test rig. Concentrations of trace elements in coal, limestone, bottom ash, cyclone ash and filter ash were determined by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Measurements show that the distribution of major and minor elements follows the ash split between the bottom ash and fly ash and that the major proportion of most of the trace elements (As, Ba, Cr, Hg, Li, Mo, Ni, Sn, V, Zn) are recovered in fly ash. Comparisons between the trace element partitioning of the runs with and without limestone addition reveal that addition of limestone shifts the partitioning of Ba, Cr, Hg, Mo, Ni, Sn, V, Zn from bottom ash to fly ash.

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Selc¸uk, Nevin, Aykan Batu e Olcay Oymak. "NOx Emissions From Combustion of High Sulfur Lignite in an ABFBC Test Rig". In 17th International Conference on Fluidized Bed Combustion. ASMEDC, 2003. http://dx.doi.org/10.1115/fbc2003-109.

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NOx emissions from fluidized bed combustion of various coals have extensively been investigated and well documented. However, NOx emissions from combustion of Turkish lignites with high ash, volatile matter and sulfur contents have not drawn much attention to date. Recent trend in utilization of indigenous lignites in fluidized bed boilers necessitated investigation of pollutant emissions and adaptation of fluidized bed combustion technology to these lignites. In this study, experimental results of various runs pertaining to the formation and emission of NOx from METU 0.3 MWt Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) test rig burning typical indigenous lignites; Aydin without limestone addition and Beypazari with and without limestone addition are presented. NOx profiles along the combustor show that concentrations are higher in bed compared to those in freeboard and that conditions leading to higher unburned volatiles in freeboard enhances NOx reduction in that region. Limestone addition results in higher concentrations of NOx in bed but lower concentrations in freeboard, albeit insignificantly.

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El Fami, Nisrine, Hind Agourrame, Nacer Khachani, Ali Boukhari e Adeljebbar Diouri. "Influence of the Variability of Limestone and Fly Ash on the Setting and Mechanical Properties of a Moroccan Composite Cement". In 4th International Conference on Bio-Based Building Materials. Switzerland: Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/www.scientific.net/cta.1.549.

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The Moroccan cement industry is looking for new processes to effectively minimize the high energy costs associated to cement manufacturing. This work presents the effect of three types of limestone with different chemical compositions and different CaCO3 contents on the physical and mechanical properties of resulting composite cements by the addition of fly ash in the proportions by weight of: 5 % and 10 %. The samples are studied in order to evaluate the interaction between different types of limestone and fly ash. Ternary cements based on fly ash-limestone-clinker induce a significant prolongation of the setting time compared to binary cements based on limestone-clinker. The substitution of clinker by limestone induces an improvement in mechanical strength compared to ternary cements in the first days; at 28 days, cements prepared with fly ashes reach significant strength due to their pozzolanic reaction.

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Vlahović, Milica, Aleksandar Savić, Sanja Martinović, Nataša Đorđević, Zoran Stević e Tatjana Volkov Husović. "Enhancing properties of concrete by addition of fly ash from a thermal power plant for application in geothermal systems". In 8th International Conference on Renewable Electrical Power Sources. SMEITS, 2020. http://dx.doi.org/10.24094/mkoiee.020.8.1.77.

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Electric power in Serbia is predominantly provided by thermal power plants. All of eleven existing thermal power plants in Serbia use coal, mainly lignite in the electricity production process thus generating about 6 million tons of fly ash per year. The estimated amount of fly ash from thermal power plants accumulated in Serbian landfills exceeds 200 million tons. On the other hand, during the last decades, respecting the principles of ecologically sustainable development has been imposed on industries, and one of them is the construction industry. Due to the presence of amorphous SiO2 and Al2O3, fly ash as pozzolanic material is convenient for the production of concrete and mortar. Consequently, multiple positive effects can be expected by the proper consumption of fly ash- reducing landfills and improving concrete properties. The idea of this study is to analyze the possibility of recycling fly ash from a thermal power plant by replacing a part of common mineral filler- limestone in the production of self-compacting concrete (SCC). Properties of conventional SCC with limestone and compositions with different fly ash content were compared. Considering that requirements for SCC should be satisfied and all properties remain or enhance in the case of fly ash addition, this study proved that all designed concretes can be used for structural applications.

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Huang, Yaji, Baosheng Jin, Zhaoping Zhong, Rui Xiao e Hongcang Zhou. "Effects of Solid Additives on the Control of Trace Elements During Coal Gasification". In 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78030.

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Based on the Modified Geo-chemical Enrichment Factor (MGEF), the contents of As, Cd, Co, Cr, Cu, Mn, Hg, Pb, V, Se, Sr, Zn in coal and coal char were analyzed by using Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS) and Inductively Couple Plasma-atomic Emission Spectroscopy (ICP-AES). Limestone, dolomite and sodium carbonate were studied to control trace elements during coal gasification. Different additives show different performances in the control of trace elements. The adsorbing capacity of coal char to all of trace elements enhances when coal is mixed with limestone and dolomite. Chemical adsorption and physical adsorption of lime, which is decomposition product of limestone under high gasification temperature, are both important for As, Co, Cr, Se and Zn. The effects of limestone on Cd, Cu, Hg, Pb, V and Sr are merely caused by physical adsorption of CaO and the adsorbing capacity to Cd, Cu, V is much stronger than those to Hg, Pb, Sr. Dolomite has stronger adsorbing capacity to most of elements (except Cu, Se, Sr) than limestone. Addition of Na2CO3 decreases the MGEFs of As, Cd, Cr, Pb and Se while increases the MGEFs of Zn in coal char. Na2CO3 has little effect on the MGEFs of Co, Cu, Hg, V and Sr in coal char.

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IBÁÑEZ GOSÁLVEZ, JAVIER, Teresa Real-Herráiz e José Marcos Ortega. "Microstructure, durability and mechanical properties of mortars prepared using ternary binders with addition of slag, fly ash and limestone". In 1st International Electronic Conference on Applied Sciences. Basel, Switzerland: MDPI, 2020. http://dx.doi.org/10.3390/asec2020-08531.

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Rassat, Scot D., e E. James Davis. "Raman Spectroscopy Measurements of Single Reacting Aerosol Microparticles". In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/laca.1994.tha.4.

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The chemical reaction between sorbent particles and sulfur dioxide (SO2) is used to remove SO2 from stack gases. The addition of powdered limestone to coal in the fluidized bed coal combustor generates calcium oxide (CaO) which reacts with the SO2 to form CaSO3 at low temperatures and CaSO4 at temperatures above 700 K. The utilization of the limestone is known to be low (about 20%) because the pores of the CaO plug as the product forms. This research was conducted to examine the reaction between CaO and SO2 to elucidate the rate-controlling processes, to generate CaO particles with a more open pore structure, and to develop techniques for single particle measurements at elevated temperatures.

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Brachaczek, Wacław, Adam Chleboś, Magdalena Kupczak, Sebastian Spisak, Michał Stybak e Katarzyna Żyrek. "Influence of the Addition of Ground Granulated Blast Furnace Slag, Fly Silica Ash and Limestone on Selected Properties of Cement Mortars". In MATBUD’2023. Basel Switzerland: MDPI, 2023. http://dx.doi.org/10.3390/materproc2023013032.

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Rapporti di organizzazioni sul tema "Limestone addition"

Barrett, Timothy, Hongfang Sun e W. Jason Weiss. Performance of Portland Limestone Cements: Cements Designed to Be More Sustainable That Include up to 15% Limestone Addition. Purdue University, dicembre 2013. http://dx.doi.org/10.5703/1288284315335.

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Herring, Theodore, Justin Tweet e Vincent Santucci. Wind Cave National Park: Paleontological resource inventory (public version). National Park Service, giugno 2023. http://dx.doi.org/10.36967/2299620.

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Wind Cave National Park (WICA), the first cave in the world to become a national park, is famous for the park’s namesake feature. Wind Cave, named for the noticeable wind-flow patterns observed as air moves in and out of the natural cave entrance, is currently the third longest cave system in the United States and seventh longest in the world. Wind Cave formed when groundwater dissolved buried layers of the fossiliferous Madison Limestone, which were deposited during the Mississippian subperiod approximately 359 to 347 million years ago. In addition to the Madison Limestone, several other formations are exposed within the park, dating from the early Proterozoic to the Holocene. The presence of fossils within the park has been known since at least the late 19th century when early settlers explored the cave to turn the geologic feature into a tourist attraction. However, most of the geologic work conducted during the park’s history has focused on the exploration and development of the cave itself, rather than its fossils. Paleontology became a bigger focus in the late 20th century when the park partnered with the South Dakota School of Mines and Technology to recover and research fossils found within the cave and on the park’s surface. Other partnerships include those with the Mammoth Site of Hot Springs and Northern Arizona University, through which researchers have studied Quaternary cave deposits found across the park. In ascending order (oldest to youngest), the geologic formations at WICA include undifferentiated lower Proterozoic rocks (Precambrian), Harney Peak Granite (Precambrian), Deadwood Formation (Cambrian–Ordovician), Englewood Limestone (Devonian–Mississippian), Madison Limestone (Mississippian), Minnelusa Formation (Pennsylvanian–Permian), Opeche Shale (Permian), Minnekahta Limestone (Permian), Spearfish Formation (Permian–Triassic), Sundance Formation (Middle–Upper Jurassic), Unkpapa Sandstone (Upper Jurassic), Lakota Formation (Lower Cretaceous), Fall River Formation (Lower Cretaceous), White River Group (Eocene–Oligocene), and Quaternary alluvium, conglomerate, and gravel deposits. The units that are confirmed to be fossiliferous within the park are the Deadwood Formation, Englewood Limestone, Madison Limestone, and Minnelusa Formation, which contain a variety of marine fossils from a shallow sea deposition environment; the Sundance Formation, which has much younger marine fossils; the Lakota Formation, which has yielded petrified wood; and the White River Group and Quaternary deposits, which contain vertebrate and invertebrate fossils deposited in and near freshwater streams, lakes, and ponds. Many of the fossils of WICA are visible from or near public trails and roads, which puts them at risk of poaching or damage, and there is evidence that fossil poaching occurred at several of the Klukas sites soon after they were discovered. Furthermore, there are several fossil sites on the tour routes within Wind Cave, which are of value to interpretation and the park experience. WICA has implemented cyclic fossil surveys in the past to monitor site conditions, and it is recommended that this paleontological resource monitoring be continued in the future.

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Baral, Aniruddha, Jeffery Roesler e Junryu Fu. Early-age Properties of High-volume Fly Ash Concrete Mixes for Pavement: Volume 2. Illinois Center for Transportation, settembre 2021. http://dx.doi.org/10.36501/0197-9191/21-031.

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High-volume fly ash concrete (HVFAC) is more cost-efficient, sustainable, and durable than conventional concrete. This report presents a state-of-the-art review of HVFAC properties and different fly ash characterization methods. The main challenges identified for HVFAC for pavements are its early-age properties such as air entrainment, setting time, and strength gain, which are the focus of this research. Five fly ash sources in Illinois have been repeatedly characterized through x-ray diffraction, x-ray fluorescence, and laser diffraction over time. The fly ash oxide compositions from the same source but different quarterly samples were overall consistent with most variations observed in SO3 and MgO content. The minerals present in various fly ash sources were similar over multiple quarters, with the mineral content varying. The types of carbon present in the fly ash were also characterized through x-ray photoelectron spectroscopy, loss on ignition, and foam index tests. A new computer vision–based digital foam index test was developed to automatically capture and quantify a video of the foam layer for better operator and laboratory reliability. The heat of hydration and setting times of HVFAC mixes for different cement and fly ash sources as well as chemical admixtures were investigated using an isothermal calorimeter. Class C HVFAC mixes had a higher sulfate imbalance than Class F mixes. The addition of chemical admixtures (both PCE- and lignosulfonate-based) delayed the hydration, with the delay higher for the PCE-based admixture. Both micro- and nano-limestone replacement were successful in accelerating the setting times, with nano-limestone being more effective than micro-limestone. A field test section constructed of HVFAC showed the feasibility and importance of using the noncontact ultrasound device to measure the final setting time as well as determine the saw-cutting time. Moreover, field implementation of the maturity method based on wireless thermal sensors demonstrated its viability for early opening strength, and only a few sensors with pavement depth are needed to estimate the field maturity.

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Rich, Megan, Charles Beightol, Christy Visaggi, Justin Tweet e Vincent Santucci. Vicksburg National Military Park: Paleontological resource inventory (sensitive version). National Park Service, marzo 2023. http://dx.doi.org/10.36967/2297321.

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Vicksburg National Military Park (VICK) was established for its historical significance as a one of the principle military sieges resulting in a turning point during the American Civil War. The steep terrain around the city of Vicksburg was integral in the military siege, providing high vantage points and a substrate that was easy to entrench for the armies, but unknown to many is the fossil content, particularly a diversity of fossil mollusks. These fossils at VICK are important paleontological resources which have yet to receive focused attention from park staff, visitors, and researchers. The park’s geology is dominated by windblown silt from the last Ice Age which overlays river-transported gravels and bedrock of the late Oligocene–early Miocene-age Catahoula Formation or early Oligocene Vicksburg Group. The park is home to the type section (a geological reference locality upon which a formation is based) for the Mint Spring Formation, one of the most fossiliferous formations in this group (Henderson et al. 2022). Beginning roughly 32 million years ago (Dockery 2019), the early Oligocene deposits of the Vicksburg Group were deposited as the sea level along the Gulf Coast shore repeatedly rose and fell. The eponymously named Vicksburg Group is comprised of, from oldest to youngest, the Forest Hill, Mint Spring, Marianna Limestone, Glendon Limestone, Byram, and Bucatunna Formations. Each of these formations are within VICK’s boundaries, in addition to outcrops of the younger Catahoula Formation. Paleozoic fossils transported by the ancestral Mississippi River have also been redeposited within VICK as pre-loess stream gravels. Overlying these layers is the Quaternary-age silt which composes the loess found throughout VICK, meaning the park’s fossils span the entire Phanerozoic Eon. The fossils of VICK consist mostly of near-shore marine Oligocene invertebrates including corals, bryozoans, bivalves, gastropods, scaphopods, ostracods, and more, though terrestrial and freshwater snails of the loess, microfossils, plant fossils, occasional vertebrates, and others can also be found in the park. Notable historical figures such as Charles Alexandre Lesueur, Charles Lyell, and John Wesley Powell all collected fossils or studied geology in the Vicksburg area. The Vicksburg Group is culturally relevant as well, as the Glendon Limestone Formation has been identified by its embedded fossils as a source rock for Native American effigy pipes. This paleontological resource inventory is the first of its kind for VICK. Although Vicksburg fossils have most recently been studied as part of the Gulf Coast Inventory & Monitoring Network (Kenworthy et al. 2007), the park has never received a comprehensive, dedicated fossil inventory before this report. At least 27 fossil species, listed in Appendix B, have been named and described from specimens collected from within VICK’s lands, and VICK fossils can be found at six or more non-NPS museum repositories. Beginning in January 2022, field surveys were undertaken at VICK, covering nearly all the park’s wooded areas, streams, and other portions beyond the preserved trenches and tour road. Fossils were collected or observed at 72 localities. These specimens will be added into VICK’s museum collections, which previously contained no paleontological resources. Considering the minimal attention dedicated to these resources in the past, these newly acquired fossil specimens may be used in the future for educational, interpretive, or research purposes. Future park construction needs should take into account the protection of these resources by avoiding important localities or allowing collection efforts before localities become inaccessible or lost.

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Honegger, Wijewickreme e Monroy. L52325 Assessment of Geosynthetic Fabrics to Reduce Soil Loads on Buried Pipelines - Phase I and II. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), dicembre 2011. http://dx.doi.org/10.55274/r0010398.

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High soil loads on buried pipelines can lead to unacceptably high pipeline strains developed in response to permanent ground displacement. Common causes of permanent ground displacement are related to slope instability as a result of heavy precipitation or ground subsidence. In addition, several permanent ground displacement hazards are related to earthquakes including surface fault displacement, triggered landslide movement, surface ground settlement related to liquefaction, and lateral spread displacement. Result: Four specific areas of investigation were completed: 1.Performed baseline tests in moist sand to confirm minimal difference in horizontal soil restraint between moist and dry sand. 2.Performed tests to gauge the variation in horizontal load reduction with separation between the pipe and an inclined trench wall lined with two layers of geotextile. 3.Performed tests in compacted 19 mm (0.75 in) minus sand and crushed limestone (referred to locally in British Columbia as road mulch) to attempt to provide larger difference between horizontal forces developed with and without lining a trench wall with geotextile. 4.Performed tests to attempt to confirm oblique horizontal-axial soil restraint behavior reported in small-scale tests and centrifuge tests. Benefit: Rather than undertake further physical testing to better understand how the presence of single or dual layers of geotextile fabric changes the mechanisms by which soil restraint develops for horizontal ground displacement, future efforts should focus on numerical simulation preferably using discrete element methods. Until full-scale test data are available to confirm consistent prediction of oblique horizontal-axial soil restraint, the practice of treating horizontal and axial soil springs independently in the analysis of buried pipeline response to ground displacement, as is the current practice, should be maintained.

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Tweet, Justin, Holley Flora, Summer Weeks, Eathan McIntyre e Vincent Santucci. Grand Canyon-Parashant National Monument: Paleontological resource inventory (public version). National Park Service, dicembre 2021. http://dx.doi.org/10.36967/nrr-2289972.

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Abstract (sommario):

Grand Canyon-Parashant National Monument (PARA) in northwestern Arizona has significant paleontological resources, which are recognized in the establishing presidential proclamation. Because of the challenges of working in this remote area, there has been little documentation of these resources over the years. PARA also has an unusual management situation which complicates resource management. The majority of PARA is administered by the Bureau of Land Management (BLM; this land is described here as PARA-BLM), while about 20% of the monument is administered by the National Park Service (NPS; this land is described here as PARA-NPS) in conjunction with Lake Mead National Recreation Area (LAKE). Parcels of state and private land are scattered throughout the monument. Reports of fossils within what is now PARA go back to at least 1914. Geologic and paleontologic reports have been sporadic over the past century. Much of what was known of the paleontology before the 2020 field inventory was documented by geologists focused on nearby Grand Canyon National Park (GRCA) and LAKE, or by students working on graduate projects; in either case, paleontology was a secondary topic of interest. The historical record of fossil discoveries in PARA is dominated by Edwin McKee, who reported fossils from localities in PARA-NPS and PARA-BLM as part of larger regional projects published from the 1930s to the 1980s. The U.S. Geological Survey (USGS) has mapped the geology of PARA in a series of publications since the early 1980s. Unpublished reports by researchers from regional institutions have documented paleontological resources in Quaternary caves and rock shelters. From September to December 2020, a field inventory was conducted to better understand the scope and distribution of paleontological resources at PARA. Thirty-eight localities distributed across the monument and throughout its numerous geologic units were documented extensively, including more than 420 GPS points and 1,300 photos, and a small number of fossil specimens were collected and catalogued under 38 numbers. In addition, interviews were conducted with staff to document the status of paleontology at PARA, and potential directions for future management, research, protection, and interpretation. In geologic terms, PARA is located on the boundary of the Colorado Plateau and the Basin and Range provinces. Before the uplift of the Colorado Plateau near the end of the Cretaceous 66 million years ago, this area was much lower in elevation and subject to flooding by shallow continental seas. This led to prolonged episodes of marine deposition as well as complex stratigraphic intervals of alternating terrestrial and marine strata. Most of the rock formations that are exposed in the monument belong to the Paleozoic part of the Grand Canyon section, deposited between approximately 510 and 270 million years ago in mostly shallow marine settings. These rocks have abundant fossils of marine invertebrates such as sponges, corals, bryozoans, brachiopods, bivalves, gastropods, crinoids, and echinoids. The Cambrian–Devonian portion of the Grand Canyon Paleozoic section is represented in only a few areas of PARA. The bulk of the Paleozoic rocks at PARA are Mississippian to Permian in age, approximately 360 to 270 million years old, and belong to the Redwall Limestone through the Kaibab Formation. While the Grand Canyon section has only small remnants of younger Mesozoic rocks, several Mesozoic formations are exposed within PARA, mostly ranging in age from the Early Triassic to the Early Jurassic (approximately 252 to 175 million years ago), as well as some middle Cretaceous rocks deposited approximately 100 million years ago. Mesozoic fossils in PARA include marine fossils in the Moenkopi Formation and petrified wood and invertebrate trace fossils in the Chinle Formation and undivided Moenave and Kayenta Formations.

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