Добірка наукової літератури з теми "Calcined marlstones"

Nowadays, researchers have made attempts to seek for cost-effective and eco-friendly catalyst for transesterification reaction. One possible way to reduce the costs of the catalysts is to use biomass or industrial waste as catalytic materials. The use of waste materials as catalysts also reduces the cost of waste handling and disposal. The objective of this study was to investigate the potential of the low cost, environmentally friendly calcined marlstones to be a viable catalyst in the transesterification of Jatropha seed oil. The calcination of marlstones was conducted at 900 °C for 4 h, and then the modification of calcined marlstones via hydration-dehydration treatment. The effects of different preparation conditions on biodiesel yield were investigated. The solid catalyst was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and the Brunauer-Emmett-Teller (BET) method. The highest biodiesel yield of 97.56% for modified calcium oxide (CaO) catalyst was obtained under the optimum condition (reaction time 5 min, microwave power 600 W, methanol/oil molar ratio 9:1, and catalyst dosage 7 wt%). It was showing potential applications of novel catalyst in biodiesel industry.

Diagenesis is a key controlling factor on sandstone porosity and permeability. Understanding type, paragenetic sequence and spatial patterns of cements is thus important for assessing sandstone hydrocarbon reservoir properties. In this study Unmanned Aerial Vehicle (UAV) photogrammetry is used to evaluate the shape and spatial distribution of calcite concretions developed within the sand-prone fill of a turbidite channel. The studied channel-fill is entrenched into hemipelagic marlstones and include a lower conglomeratic sandstone loaded with marlstone rip-ups and an upper fill featuring a range of turbidite bed types, which, up-section and off the channel axis, are progressively finer grained and less amalgamated. Concretion shape analysis highlighted a continuum of equant to oblate shapes with flat-lying major axes and a cumulative volume fraction of ca. 22%. Equant to sub-equant concretions are ubiquitous and occur at different heights within beds, often developing around marlstone rip-ups. Conversely, elongated concretions are either strata-bound concretions or completely cemented beds which become volumetrically dominant up section and off the channel axis. The interparticle pore-space of concretions represents on average ca. 22% and is tightly filled by poikilotopic and blocky calcite cement precipitated near to maximum burial depth, whereas host sandstones lack calcite cements and show smectite clay cement and an average preserved porosity of ca. 15%. The oxygen and carbon isotopes of calcite cements point to the marlstone as the main source of carbonate ions, suggesting concretions developed during burial by either diffusion from rip-ups and mud caps or recrystallization of, matrix micrite. Results suggest that the process by which the carbonate-rich component was eroded from the substrate and trapped within the channel-fill is a key control on spatial distribution of calcite concretions, likely to reflect on spatial variability of reservoir properties.

Working with shales in the fourth member of Shahejie Formation in the Dongying Depression in Bohai Bay Basin of East China, this study examines the facies classification, petrological characteristics, pore size distribution, and pore connectivity of oil-producing shale. The studied shales could be classified into five sedimentary facies according to a three-step classification criterion that consists of total organic carbon (TOC), sedimentary structure, and mineral composition. Among them, the “low TOC massive siliceous mudstone” and “low TOC layered clayey mudstone” facies have similar distributions from low-pressure N2 physisorption, and the incremental volume within the 3-30 nm pore size range is much higher than the “high TOC laminated clayey marlstone” and “low TOC layered siliceous marlstone” facies. The T 2 spectra of nuclear magnetic resonance tests for the “high TOC laminated clayey marlstone” facies which contains abundant calcite laminae and organic matter-hosted pores commonly show three peaks, with a dominant peak at less than 300 nm in diameter and good pore connectivity. The T 2 spectra of three other facies are both characterized by two peaks, and the main peak of the “low TOC layered siliceous marlstone” and “low TOC layered clayey mudstone” facies has a similar range at 2-500 nm, in contrast with 1-17 nm for the “low TOC massive siliceous mudstone” facies. Pores in these four facies are mainly at nanoscales with predominant pore-throat diameters at less than 50 nm; however, the “high TOC laminated clayey marlstone” facies has the largest peak in the range of >1 μm, possibly because of its interlaminar structure and microcracks. The spontaneous imbibition experiments using two distinct fluids indicated that all of four facies have a much better pore connectivity towards the hydrophilic fluid than these experienced by the hydrophobic fluid.

This study focused on natural materials such as clinoptilolite (CLI), metakaolin (MK), marlstone (MRL) and phonolite (PH). Clinoptilolite is one of the most known and common natural minerals (zeolites) with a unique porous structure, metakaolin is calcined kaolin clay, marlstone is a sedimentary rock and phonolite is an igneous rock composed of alkali feldspar and other minerals. These natural materials are mainly used in the building industry (additions for concrete mixtures, production of paving, gravels) or for water purification, but the modification of their chemical, textural and mechanical properties makes these materials potentially usable in other industries, especially in the chemical industry. The modification of these natural materials and rocks was carried out by leaching using 0.1 M HCl (D1 samples) and then using 3 M HCl (D2 samples). This treatment could be an effective tool to modify the structure and composition of these materials. Properties of modified materials were determined by N2 physisorption, Hg porosimetry, temperature programmed desorption of ammonia (NH3-TPD), X-ray fluorescence (XRF), X-ray powder diffraction (XRD), diffuse reflectance infrared Fourier transform (DRIFT) and CO2 adsorption using thermogravimetric analysis (TGA). The results of N2 physisorption measurements showed that that the largest increase of specific surface area was for clinoptilolite leached using 3M HCl. There was also a significant increase of the micropore volume in the D2 samples. The only exception was marlstone, where the volume of micropores was zero even in the leached sample. Clinoptilolite had the highest acidity and sorption capacity of CO2. TGA showed that the amount of CO2 adsorbed was not significantly related to the increase in specific surface area and the opening of micropores. Hg porosimetry showed that acid leaching using 0.1 M HCl and 3 M HCl resulted in a significant increase in the macropore volume in phonolite, and during leaching using 3M HCl there was an increase of the mesopore volume. From the better properties, cost-efficient and environmental points of view, the use of these materials could be an interesting solution for catalytic and sorption applications.

Abstract. New information on the PM10 mineral dust from site-specific (Rome area, Latium) outcropped rocks, and on the microphysics, optical properties and radiative effects of mineral dust at local level were gained in this work. A multi-disciplinary approach was used, based on individual-particle scanning electron microscopy with X-ray energy-dispersive microanalysis (SEM XEDS), X-ray diffraction (XRD) analysis of dust, size distribution of mineral particles, and radiative transfer modelling (RTM).The mineral composition of Rome lithogenic PM10 varies between an end-member dominated by silicate minerals and one exclusively composed of calcite. The first is obtained from volcanic lithotypes, the second from travertine or limestones; lithogenic PM10 with intermediate composition derives mainly from siliciclastic rocks or marlstones of Rome area. Size and mineral species of PM10 particles of silicate-dominated dust types are tuned mainly by weathering and, to lesser extent, by debris formation or crystallization; chemical precipitation of CaCO3 plays a major role in calcite-dominated types. These differences are evidenced by the diversity of volume distributions, within either dust types, or mineral species. Further differences are observed between volume distributions of calcite from travertine (natural source) and from road dust (anthropic source), specifically on the width, shape and enrichment of the fine fraction (unimodal at 5 μm a.d. for travertine, bimodal at 3.8 and 1.8 μm a.d. for road dust). Log-normal probability density functions of volcanics and travertine dusts affect differently the single scattering albedo (SSA) and the asymmetry parameter (g) in the VISible and Near Infrared (NIR) regions, depending also on the absorbing/non-absorbing character of volcanics and travertine, respectively. The downward component of the BOA solar irradiance simulated by RTM for a volcanics-rich or travertine-rich atmosphere shows that volcanics contribution to the solar irradiance differs significantly from that of travertine in the NIR region, while similar contributions are modelled in the VIS.

Abstract. In this work, new information has been gained on the laboratory-resuspended PM10 fraction from geological topsoil and outcropped rocks representative of the Rome area (Latium). Mineralogical composition, size distribution, optical properties and the surface radiative forcing efficiency (RFE) of dust types representing the compositional end members of this geological area have been addressed. A multi-disciplinary approach was used, based on chamber resuspension of raw materials and sampling of the PM10 fraction, to simulate field sampling at dust source, scanning electron microscopy/X-ray energy-dispersive microanalysis (SEM XEDS) of individual mineral particles, X-ray diffraction (XRD) analysis of bulk dust samples, building of number and volume size distribution (SD) from microanalysis data of mineral particles and fitting to a log-normal curve, and radiative transfer modelling (RTM) to retrieve optical properties and radiative effects of the compositional end-member dust samples. The mineralogical composition of Rome lithogenic PM10 varies between an end-member dominated by silicate minerals (from volcanics lithotypes), and one mostly composed of calcite (from travertine or limestones). Lithogenic PM10 with intermediate composition derives mainly from siliciclastic rocks or marlstones. Size and mineral species of PM10 particles of silicate-dominated dust types are tuned mainly by rock weathering and, to lesser extent, by debris formation or crystallization; chemical precipitation of CaCO3 plays a major role in calcite-dominated types. These differences are reflected in the diversity of volume distributions, either within dust types or mineral species. Differences are also observed between volume distributions of calcite from travertine (natural source; SD unimodal at 5 μm a.d.) and from road dust (anthropic source; SD bimodal at 3.8 and 1.8 μm a.d.). The volcanics and travertine dusts differently affect the single scattering albedo (SSA) and the asymmetry parameter (g) in the visible (VIS) and near-infrared (NIR) regions. The downward component of the bottom-of-atmosphere (BOA) solar irradiance simulated by RTM for an atmosphere where only volcanics (or only travertine dust) composes the aerosol, shows that the volcanics contribution to the solar irradiance differs significantly from that of travertine in the NIR region, while similar contributions are modelled in the VIS. The RFE (−293 W m−2 for volcanics and −139 W m−2 for travertine, at 50° solar zenith angle) shows that volcanics dust produces a stronger cooling effect at surface than travertine, as expected for more absorbing aerosols.

The karst fracture-cave oil and gas reservoirs of the Yingshan Formation in the northern slope of the Tazhong Uplift are well developed and have achieved good exploration results. However, the karst fracture-cave near the top of the Yingshan Formation is basically filled with mud fillings, which seriously affect the reservoir property, and the source and filling environment of the mud fillings have been unclear. Through the petrological and geochemical analysis of the fracture-cave fillings system in the typical wells of the Yingshan Formation, it has been found that (1) the fracture-cave fillings are mainly composed of a mixture of the bedrock dissolution dissociation particles, clay minerals, and calcite cements of the Yingshan Formation, and the content of each component in the different wells or in the cave interval is quite different. (2) Rare earth element analysis shows that the rare earth distribution pattern of the fracture-cave fillings is similar to the bottom marlstone of the Lianglitage Formation, indicating that the fracture-cave fillings should be mainly derived from the early seawater of the deposition during the Lianglitage Formation. (3) Cathodoluminescence, trace element analysis, and previous studies have shown that the formation and fillings of the fractures and caves mainly occurred in the hypergene period, which had the characteristics of an oxidized environment, and that there are two filling effects. First, the limestone of the Yingshan Formation experienced the formation of karst caves due to meteoric freshwater dissolution during the exposure period, and the limestone of the Yingshan Formation was dissolved, resulting in some insoluble clay and residual limestone gravel particles brought into the cave by the meteoric freshwater for filling. Second, the seawater transgression also played an important role during the deposition of the Lianglitage Formation. The clay content in the seawater was high during the early deposition of the Lianglitage Formation, which led to the clay being brought into the caves by the seawater during the deposition of the Lianglitage Formation for further filling; at the same time, calcite deposited into the caves with the clay. The above research promotes the study of the formation mechanism of the karst cave reservoir in the Yingshan Formation and has important theoretical significance for the guiding of the next oil and gas exploration in this area.

Abstract Scelidosaurus fossils were first discovered during the commercial quarrying of the Liassic sea-cliffs between Charmouth and Lyme Regis in Dorset during the late 1850s. The original specimens included a well-preserved skull embedded in a block of argillaceous limestone (marlstone). Shortly after this skull was retrieved, a series of more-or-less contiguous marlstone slabs were recovered, containing most of the skeleton of the same animal (NHMUK R1111). After rudimentary (hammer and chisel) mechanical preparation, Owen published descriptions of this material (Owen, 1861, 1863). These two monographs have been the sole references pertaining to the anatomy of Scelidosaurus for >150 years. The skeleton of the lectotype of Scelidosaurus harrisonii (NHMUK R1111) has since been extracted from the surrounding matrix using an acid-immersion technique. Some additional specimens held in the collections of the Natural History Museum London, the Bristol City Museum and the Sedgwick Museum in Cambridge provide anatomical material that allows detailed description of this taxon, for which we have had, until now, a surprisingly poor understanding. Axial skeleton: The axial skeleton of Scelidosaurus comprises eight cervical, 16 dorsal, four sacral and > 40 caudal vertebrae. During ontogeny, the posterior centrum articular surface of the 16th dorsal vertebra develops a firm, ligament-bonded junction with the succeeding sacral centrum. Apart from the atlas rib, which is single headed, double-headed ribs are present throughout the presacral vertebral series, and none shows any indication of fusion to its associated vertebra. However, those ribs attached to cervical vertebrae 2–4 were evidently bound firmly by connective tissue to rugose diapophyses. The last two (presacral) dorsal ribs show merger of the capitulum and tuberculum, meaning that they are separated by only a step. The angulation and arching of the dorsal ribs suggest that these animals had a broad (barrel-like) torso. Intercostal uncinate plates were present, attached to the posterior margins of some of the largest dorsal ribs. Their attachment sites are clearly marked, and these plates might have been composed of calcified cartilage in larger individuals. The sacral vertebrae fuse progressively during ontogeny, in an anterior-to-posterior sequence. The sacral ribs are long and robust, and tilt the iliac blade outward dorsally. A sacricostal ‘yoke’ (created by the fusion of the distal ends of adjacent sacral ribs) never forms. The base of the tail has a unique ball-and-socket-style joint between the centra of caudal vertebrae 1 and 2 in only one skeleton. This might have permitted powerful, but controlled, movements of the tail as a defensive weapon (or increased flexibility at the base of the tail, which might have been necessary for reproduction). Caudal ribs are initially long, blade-shaped projections that gradually decrease in size and become stub-like remnants that persist as far back as the midtail (approximately caudal vertebra 25). Haemal arches (chevrons) disappear nearer to the distal end of the tail (approximately caudal vertebra 35). Ossified tendons are preserved as epaxial bundles that are clustered in the ‘axillary’ trough (between the neural spine and transverse processes on either side of the midline). Ossified tendons are restricted to the dorsal and sacral region. Flattened ossified tendons are fused to the sides of sacral neural spines. In life, the ossified tendons might have formed a low-angled trellis-like arrangement. Appendicular skeleton: The pectoral girdle comprises a long scapula, with a distally expanded blade. The proximal portion is expanded and supports an oblique promontory, forming an acromial process anteriorly and a thick, collar-like structure posteriorly above the glenoid. Between these two features is a shallow basin, bordered ventrally by a sutural edge for the coracoid. The scapula–coracoid suture remains unfused in large (5-m-long) individuals. The coracoid bears a discrete foramen and forms a subcircular dished plate, with the shallowest of embayments along its posterior edge. Clavicles are present as small fusiform bones attached to the acromial process of the scapulae and leading edge of each coracoid. A sternum was reported as ‘some partially ossified element of the endoskeleton’ Owen (1863: 13), but subsequent preparation of the skeleton has removed all trace of this material. The humerus is relatively long and has a prominent rectangular and proximally positioned deltopectoral crest. The ulna is robust and tapers distally, but there is no evidence of an olecranon process. The radius is more rod-like and terminates distally in an enlarged, subcircular and convex articular surface for the carpus. The carpus is represented by an array of five discoid carpals. The manus is pentadactyl and asymmetrical, with short, divergent metacarpals and digits that terminate in small, arched and pointed unguals on digits 1–3 (only). The phalangeal formula of the manus is 2-3-4-3-2. The pelvis is dominated by a long ilium; the preacetabular process is arched, transversely broad, and curves laterally. In juveniles, this process is short and horizontal, but during ontogeny it increases considerably in length and becomes arched. The iliac blade is tilted laterally, meaning that its dorsal blade partly overhangs the femur. The acetabulum forms a partial cupola, and there is a curtain-like medial wall that reduces the acetabular fenestra to a comparatively low, triangular opening between the pubis and ischium. The postacetabular portion of the ilium is long and supports a brevis shelf. The ischium has a long, laterally compressed shaft that hangs almost vertically beneath the ilium, and there is no obturator process. The pubis has a long, narrow shaft and a relatively short, deep, laterally compressed prepubic process that twists laterally (its distal end lies almost perpendicular to the long axis of the ilium). The articular pad on the pubis for the femoral head faces posteriorly. The obturator foramen is not fully enclosed within the pubis, but its foramen is closed off posteriorly by the pubic peduncle of the ischium. The femur is stout and has a slightly medially offset femoral head, and the greater trochanter forms a sloping shoulder continuous with, and lateral to, the femoral head. The anterior (lesser) trochanter is prominent and forms a thick, thumb-shaped projection on the anterolateral corner of the femoral shaft. The fourth trochanter is pendent and positioned at midshaft. In larger individuals, it appears to become thickened and reinforced by becoming coated with metaplastic bone derived from the tendons attached to its surface. The distal end of the femoral shaft is slightly curved and expands to form condyles. There is a deep and broad posterior intercondylar groove, but the anterior intercondylar groove is barely discernible in juveniles and not much better developed in subadults. The tibia and fibula are shorter than the femur. The tibia is structurally dominant, and the shorter fibula is comparatively slender and bowed. The proximal tarsals are firmly bound by connective tissue to the distal ends of the tibia and fibula. The distal end of the tibia is stepped, which aids the firm interlock between the crus and proximal tarsals. There appear to be two roughly discoid tarsals (distal tarsals 3 and 4), and a rudiment of distal tarsal 5 appears to be sutured to the lateral margin of distal tarsal 4. Five metatarsals are preserved, but the fifth is a splint of bone attached to the proximal end of metatarsal 4. Metatarsals 2–4 are dominant, long and are syndesmotically interlocked proximally, but their shafts splay apart distally. Metatarsal 1 is much shorter than the other three, but it retains two functional phalanges (including a short, pointed ungual). The foot is anatomically tetradactyl but functionally tridactyl. The pedal digit formula is 2-3-4-5-0. The digits diverge, but each appears to curve medially along its length, creating the impression of asymmetry. This asymmetry is emphasized, because the three principal unguals are also twisted medially. The ungual of digit 2 is the largest and most robust of the three, whereas that of digit 4 is the smallest and least robust. The general girth of the torso and the displacement of the abdomen posteriorly (a consequence of the opisthopubic pelvic construction in this dinosaur) constrained the excursion of the hindlimb during the protraction phase of the locomotor cycle. The anterolateral displacement of the hindlimb during protraction is in accord with the freedom of motion that is evident at the acetabulum, the susceptibility of the hindlimb to torsion between and within its component parts, and the asymmetry of the foot. It is probable that thyreophorans (notably, ankylosaurs) used a similar oblique-parasagittal hindlimb excursion to accommodate their equally large and wide abdomens. This surmise accords with the structure of the pelves and hindlimbs of ankylosaurs. Derived stegosaurs might have obviated this ‘problem’, in part, because their hindlimbs were longer and their torsos and abdomens narrower and capable of being ‘stretched’ vertically to a greater extent. Nevertheless, the structure of their acetabula and hindlimbs indicates that the oblique-parasagittal style of hindlimb excursion remained a possibility and might be an evolutionary remnant of the locomotor style of basal, shorter-limbed stegosaurs. A reconstruction of the endoskeleton of Scelidosaurus is presented on the basis of this updated description. Although quadrupedal, this animal was only facultatively so, judged by its forelimb-to-hindlimb proportions and structure; it therefore betrays bipedality in its ancestry.

L’utilisation de Supplementary Cementitious Materials (SCMs) en substitution du clinker est une technologie aujourd’hui bien connue qui permet de réduire le coût environnemental du ciment. Parmi les SCMs largement utilisés on retrouve les cendres volantes, les laitiers de hauts fourneaux ou encore la poudre de verre. Dans les dernières années, un intérêt grandissant s’est développé pour l’utilisation d’argiles calcinées comme ajouts cimentaires, notamment du fait de leur forte réactivité et leur grande disponibilité. Ce projet de thèse s’intéresse à l’utilisation d’argiles et de marnes calcinées comme ajouts cimentaires. L’objectif principal est d’identifier de nouveaux échantillons susceptibles de présenter un intérêt pour une utilisation comme SCMs. Pour ce faire, une approche multi-échelle macro et micro est utilisée afin d’étudier de manière précise la calcination, la réactivité pouzzolanique et le comportement en système cimentaire de ces nouveaux échantillons. Il a été possible de démontrer que les marnes (malgré leur composition minéralogique complexe) présentent un potentiel d’utilisation comme ajout cimentaire après calcination, et ce, même avec une faible proportion d’argiles. Par la suite, il a été démontré que la palygorskite est une argile à haut potentiel pour une utilisation comme ajout cimentaire après calcination, et peut être considérée comme une alternative viable au métakaolin. L’étude poussée de l’utilisation de palygorskites calcinées comme ajouts cimentaires a également permis d’apporter de nouvelles connaissances fondamentales sur la compréhension des mécanismes impliqués lors de la calcination de ce type de matériaux
The use of Supplementary Cementitious Materials (SCMs) as a substitute for clinker is a well-known technology that can reduce the environmental cost of cement. Among the SCMs widely used today are fly ash, blast furnace slag and glass powder. In recent years, there has been a growing interest in the use of calcined clays as SCMs, particularly due to their high reactivity and availability.This thesis project focuses on the use of calcined clays and marlstones as supplementary cementitious materials. The main aim is to identify new materials that could be of interest for use as SCMs. To this end, a multi-scale macro/micro approach is used to study the calcination, pozzolanic reactivity and performance in cementitious systems of these new materials. It was possible to demonstrate that marlstones (despite their complex mineralogical composition) have the potential to be used as supplementary cementitious materials after calcination, even with a low proportion of clays. Subsequently, it was shown that palygorskite is a high potential clay for use as a supplementary cementitious material after calcination, and can be considered as a viable alternative to metakaolin. The extensive study of the use of calcined palygorskites as SCMs has also provided new fundamental insights into the understanding of the mechanisms involved in the calcination of this type of material