Academic literature on the topic 'Multimineral method'

Multimineral log analysis is a quantitative formation evaluation tool for geologic and petrophysical reservoir characterization. Rock composition can be estimated by solving equations that relate log measurements to the petrophysical endpoints of minerals and fluids. Due to errors in log data and uncertainties in petrophysical endpoints of constituents, we have used effective medium models from rock physics as additional independent information to validate or constrain the results. We examine the Voigt-Reuss (VR) bound model, self-consistent approximation (SCA), and differential effective medium (DEM). The VR bound model provides the first-order quality control of multimineral results. We first show a conventional carbonate reservoir study with intervals in which the predicted effective medium models from multimineral results are inconsistent with measured elastic properties. We use the VR bound model as an inequality constraint in multimineral analysis for plausible alternative solutions. The SCA and DEM models provide good estimates in low-porosity intervals and imply geologic information for porous intervals. Then, we present a field case of the Bakken and Three Forks formations. A linear interpolation of the VR bound model helps validate multimineral results and approximate the elastic moduli of clay. There are two major advantages to using our new method: (1) Rock-physics effective medium models provide independent quality control of petrophysical multimineral results and (2) multimineral information leads to realistic rock-physics models.

In the seasonal frozen area of northeast China, cement concrete is usually in a working environment of cold climate and chlorine erosion coupling effect. In general, with a reasonable addition of air entraining agent (AEA) and multimineral admixtures such as fly ash, blast furnace slag, and silica fume, the durability of cement concrete under the effects of freeze-thaw and salt solution can be significantly improved in cold regions. However, due to several more compositions of cement concrete with multiple mineral admixtures, it would take excessive trial mixtures to select the desired mixture proportion based on the conventional method. This means a great deal of costs of raw materials and laboratory experimental time. In this paper, the experimental scheme of mixture proportion for air-entrained concrete with multimineral admixtures was designed based on the orthogonal experiment design method. Based on the compressive strength, rapid chloride permeability, and weight loss and relative dynamic elastic modulus after salt freeze-thaw cycles, the influence of different mineral admixtures and their dosages on the durability of concrete subjected to freeze-thaw in salt solution was analyzed. After that, based on genetic algorithm, an optimization of mixture proportion was proposed, which only requires less trial mixes and accessible optimization process. The test results indicated the superiority of air-entrained concrete with multimineral admixtures when serving in salt freeze-thaw environment. Eventually, it was also verified that the optimized concrete in this paper could achieve pleasurable durability performances under salt freeze-thaw cycles.

Abstract The purpose of this study was to develop a single-laboratory validated (SLV) method using high-performance liquid chromatography with different detectors diode array detector (DAD); fluorescence detector (FLD); and mass spectrometry (MS) for determination of 7 B-complex vitamins (B1-thiamin, B2-riboflavin, B3-nicotinamide, B6-pyridoxine, B9-folic acid, pantothenic acid, and biotin) and vitamin C in multivitamin/multimineral dietary supplements. The method involves the use of a reversed-phase octadecylsilyl column (4 m, 250 2.0 mm id) and a gradient mobile phase profile. Gradient elution was performed at a flow rate of 0.25 mL/min. After a 5 min isocratic elution at 100 A (0.1 formic acid in water), a linear gradient to 50 A and 50 B (0.1 formic acid in acetonitrile) at 15 min was employed. Detection was performed with a DAD as well as either an FLD or a triple-quadrupole MS detector in the multiple reaction monitoring mode. SLV was performed using Standard Reference Material (SRM) 3280 Multivitamin/Multimineral Tablets, being developed by the National Institute of Standards and Technology, with support by the Office of Dietary Supplements of the National Institutes of Health. Phosphate buffer (10 mM, pH 2.0) extracts of the NIST SRM 3280 were analyzed by the liquid chromatographic (LC)-DAD-FLD/MS method. Following extraction, the method does not require any sample cleanup/preconcentration steps except centrifugation and filtration.

Introduction: Magnesium is an essential mineral involved in a range of key biochemical pathways. Several magnesium supplements are present on the market and their degree of bioavailability differs depending on the form of magnesium salt used. Aquamin-Mg is a natural source of magnesium, containing 72 additional trace minerals derived from the clean waters off the Irish coast. However, the in vitro bioaccessibility and bioavailability of Aquamin-Mg in comparison with other supplement sources of magnesium has yet to be tested. Method: Aquamin-Mg, magnesium chloride (MgCl2) and magnesium oxide (MgO) were subjected to gastrointestinal digestion according to the harmonized INFOGEST in vitro digestion method and in vitro bioavailability tested using the Caco-2 cell model. Magnesium concentration was measured by atomic absorption spectrophotometry (AAS). Results: Magnesium recovery from both Aquamin-Mg and MgCl2 was greater than for MgO. Magnesium from all three sources was transported across the epithelial monolayer with Aquamin-Mg displaying a comparable profile to the more bioavailable MgCl2. Conclusions: Our data support that magnesium derived from a marine-derived multimineral product is bioavailable to a significantly greater degree than MgO and displays a similar profile to the more bioavailable MgCl2 and may offer additional health benefits given its multimineral profile.

As part of a multi-well field study an integrated petrophysical workflow was developed to include the generation of fluid substituted logs for AVO characterisation.The workflow relied upon the construction of a multimineral model that best approximated the actual mineral content of the reservoir. Any limitations or assumptions were noted and taken into account when creating the multi-mineral model. Other petrophysical results were derived from the same model to validate its consistency such as intrinsic permeability, porosity, water saturation, etc. Iteration between the model and the results was required until a consistent model was achieved.The estimation of an intrinsic permeability log was based upon the k-Lambda method that uses the multimineral model and porosities.The estimation of a shear slowness log and the fluid substituted logs was based upon elastic rock properties derived from the multi-mineral model and the acquired compressional slowness log and bulk density log. This integrated approach provides a higher confidence in the derived results, which are then used as input into the reservoir model, thereby improving the reserve calculations.The interdependence of each derived result on the same input multi-mineral model ensures consistency and predictability in a complex geological environment, which captures all available information.The method is demonstrated with the Gipsy–1 and North Gipsy–1 wells, which were part of the original field study.

Traditional petrophysical methods to evaluate organic richness and mineralogy using gamma-ray and resistivity log responses are not diagnostic in source rocks. We have developed a deterministic, nonproprietary method to quantify formation variability in total organic carbon (TOC) and three key mudrock mineralogical components of nonhydrocarbon-bearing source rock strata of the Eagle Ford Group by developing a set of log-derived multimineral models calibrated with Fourier transform infrared spectroscopy core data from the research borehole U.S. Geological Survey Gulf Coast 1 West Woodway. We determined that bulk density response is a reliable indicator of organic content in these thermally immature, water-bearing source rocks. Multimineral findings indicate that a high degree of laminae-scale mineralogical heterogeneity exists due to thinly interbedded carbonate cements amid clay-rich mudstone layers. The lower part of the Eagle Ford Group contains the highest average TOC content (4.7 wt%) and the highest average carbonate volume (64.1 vol%), making it the optimal target in thermally mature areas for source-rock potential and hydraulic-fracture placement. In contrast, the uppermost portion of the Eagle Ford Group contains the highest average volume of clay minerals (42.6 vol%), which increases the potential for wellbore stability issues. Petrophysical characterization reveals that porosity is approximately 30% in this relatively uncompacted formation. In this thermally immature source rock, water saturation is nearly 100% and no free hydrocarbons were observed on the resistivity logs. No evidence of borehole ellipticity was observed on the three-arm caliper log, and horizontal stresses are presumed to be directionally uniform in the vicinity of this near-surface wellbore. This shallow wellbore has a temperature gradient of 1.87°F/100 ft (16.3°C/km) and is likely influenced by earth surface heating.

The online measurement of coal ash has overcome the shortcomings of chemical tests. However, there could be large fluctuations and errors in the results of online ash monitors because of the transient change in coal quality resulting from different geological conditions in the mining process. In this study, to resolve the problems of the dual-energy γ-ray online ash monitor in the Linhuan Coal Preparation Plant, we investigated the internal factors, such as the composition of multimineral and multicoal, and external factors, such as the moisture and impurities, which affect the measurement results of the coal ash monitor. Furthermore, we developed a mathematical model to determine the effect of relevant factors on the coefficient of the online ash monitor, which revealed the relationship between coal composition and the parameters of the ash monitor, ensuring the stable and accurate measurement of ash in clean coal. The method of determining parameters used in the case of coal blending has been applied in the Linhuan Coal Preparation Plant. By comparing with tested ash content, the average absolute error and relative error for daily ash content measured in April are 0.21 and 2.18%, respectively. Meanwhile, it shows certain accuracy and reproducibility while opposed to the daily average absolute error of 0.22 and relative error of 2.39% in May.

Abstract A rapid, simple, and accurate ion-pair RPLC method has been developed for simultaneous analysis of vitamin C and major B-complex vitamins. An RP C18 column thermostated at 30°C was used with gradient elution of mobile phase comprising 10 mM potassium dihydrogen phosphate buffer (containing 3 mM sodium hexane-1-sulfonate, adjusted to pH 2.80 with o-phosphoric acid) and methanol at a flow rate of 1.0 mL/min to achieve the best possible separation and resolution of all vitamins in about 11.00 min. The detection was performed at 274 nm. The method has been implemented successfully for simultaneous determination of vitamins present in 12 multivitamin/multimineral pharmaceutical preparations, as well as in human urine. Typical validation characteristics were evaluated in accordance with International Conference on Harmonization guidelines. Good linearity over the investigated concentration levels was observed. Intraday repeatability was ≤2.0%, and interday variation was ≤2.6%, for all vitamins. The method can be used for assay of these vitamins over a wide concentration range with good precision and accuracy; hence, it would be appropriate for routine QC as well as in clinical analysis.

L’oggetto di questa tesi è stato lo studio della mineralogia dei sedimenti fluviali ed eolici attuali generati dall’erosione della catena Himalayana, con lo scopo di definire con precisione le segnature composizionali dei diversi domini tettono-stratigrafici dell’orogene. All’approccio basato sulla identificazione e quantificazione delle associazioni di minerali pesanti (densità > 2.90 g/cm3), sono stati affiancate diverse tecniche analitiche complementari, che comprendono la petrografia e la geochimica del sedimento totale, lo studio di dettaglio al microscopio elettronico a scansione e allo spettroscopio Raman delle caratteristiche minerochimiche dei quattro principali gruppi di minerali pesanti che caratterizzano i sedimenti himalayani e orogenici in generale (anfiboli, epidoti, granati, e pirosseni), l’ analisi dei rapporti isotopici di samario e neodimio scolta in collaborazione con Peter Clift presso l’ Istituto Oceanigrafico Woods Hole, oltre all’ analisi geocronologica su zirconi detritici svolta in collaborazione con Pieter Vermeesch presso l’Università di Londra (UCL) affiancata anche da dati analoghi su rutilo, monazite, e titanite ottenuti con la collaborazione di Xiumian Hu e Ronghua Guo presso l’ Università di Nanjing. Le principali aree di studio hanno compreso il Deserto di Thal nel Pakistan centro-settentrionale e gli affluenti del Fiume Indo nel suo corso di montagna dal Ladakh fino al Punjab e gli affluenti principali del Fiume Yarlung (il nome tibetano del Brahmaputra) in Tibet meridionale. Sono stati studiati anche campioni di arenarie Cenozoiche provenienti sia dalle Alpi Occidentali che dal Tibet meridionale. I risultati presentati in questa tesi sono stati pubblicati a primo nome in un volume speciale della rivista internazionale Minerals, sono stati sottomessi nel mese di Settembre e sempre a primo nome a Sedimentary Geology, o sono in preparazione per una prossima sottomissione ad altra prestigiosa rivista internazionale.
Sediments and sedimentary rocks can be considered as geological archives that faithfully reflect their provenance information if the bias introduced by physical and chemical processes during transport and deposition can be properly recognized and corrected for. The sediment provenance analysis both in modern and ancient settings is crucial to trace the sediment sources, reconstruct paleoclimate and paleoenvironment, and interpret the evolution of the Earth’s surface. Modern sediments, unaffected by diagenesis and eroded, tansported and deposited under climatic conditions that are fully known, can provide valuable information on the interactions among the different controlling factors that govern source-to-sink systems. Rivers draining the Himalayan orogen provide the good opportunity to trace the source fingerprinting that is documented in modern fluvial and eolian sand and how these signatures reflect the erosion patterns of the modern and paleo-river systems. A multidisciplinary approach based on petrography, minerology, geochemistry and geochronology is emphasized in this research, in order to obtain a comprehensive provenance information. Our research area focused on the modern sands from two river system: Yarlung River and Indus River. In the Yarlung River system, the Nian River was chosen to investigate the petrographic, mineralogical and chronological signature of sediments from Tethys Himalaya, Greater Himalaya, Kangmar gneiss dome and Transhimalayan ophiolitic suture. Different tectonic domains are characterized by distinct heavy mineral assemblages, e.g., the first-cycle sillimanite and garnet in Greater Himalaya, and clinopyroxene, olivine and enstatite in the forearc ophiolites. Sand carried by the Nian River and its major tributaries, mainly reflects Tethys Himalayan characteristics, consistent with the geochronological results. Erosion rates were also evaluated and circumscribed in the middle Yarlung River catchment. The average erosion rate in the Nianchu catchment is estimated at 0.07-0.10 mm/a, twice as that in the middle Yarlung and Lhasa River catchments, which is principally ascribed to the high erodibility of Tethys Himalayan strata. In the Indus River system, minerochemical analysis of amphibole, garnet, epidote and pyroxene grains, and geochronological analysis of detrital zircons, associated with analysis on petrography, bulk-sediment geochemistry and isotopic geochemistry, in aolian sand from Thal Desert and fluvial sand in selected tributaries draining one specific tectonic domain in the upper Indus catchment, were carried out to discriminate compositional signatures, decipher the provenance information, and trace the erosional evolution of the western Himalaya syntaxis. The compositional fingerprints of Thal Desert sand are characterized by litho-feldspatho-quartzose to quartzo-feldspatho-lithic detrital modes and very rich amphibole-dominated heavy-mineral assemblages. The high heavy mineral concentration, less negative εNd, abundant zircon ages at 40-100 Ma, and specific mineral varietal fingerprints, consistently reflect that the Kohistan arc has acted as the main sediment source. Karakorum appears to contribute less while Himalaya shows higher influence on the Thal Desert sands than modern river sands from the Indus. As a Quaternary repository of wind-reworked Indus River sand at the entry point in the Himalayan foreland basin, Thal Desert sands document higher erosion rates than today in the glaciated areas formed largely by batholites granitoids of the Asian active margin. The close compositional and chronological connection between the Thal Desert and the ancient Indus Delta and Fan deposits, shed new light on the reconstructing of paleodrainage and the understanding of relationship between climatic and tectonic forcing that controlled the erosional evolution of the western Himalayan-Karakorum orogen.