Good Regression Relationship Research Articles

Lithology and fluid discrimination using combined seismic attributes with the constraint of rock physics: a case study from W field, South Sumatra Basin

Reservoir characterization and fluid discrimination based on seismic reflection amplitude play important roles in seismic exploration industry. Stable fluid-sensitive attributes from seismic data can help reduce uncertainties of hydrocarbon prediction in interwell locations and increase the reliability of drilling plans. In this study, in combination with seismic AVO inversion impedance and the rock physics template analysis, we proposed a new attribute (DI) to discriminate the hydrocarbon-associated anomalies and predict the reservoir parameters including porosity and water saturation quantitatively in Upper Gumai formation of W field, South Sumatra Basin. The new attribute (DI) is constructed using a set of combined impedances derived from prestack seismic inversion with the constraint of rock physics. Numerical modelling based on patchy-saturated model was implemented to test the sensitivity and stability of the new attribute and results showed that the DI attribute can predict the existence of hydrocarbon-filled sands with less ambiguity. With known well log data in W field, a feasibility study including cross-plotting and histogram methods was carried out and concluded that the DI attribute contributes higher resolution in distinguishing the hydrocarbon-filled sands from the background trend. In the process of quantitative interpretation, the DI attribute shows a good regression relationship with porosity and water saturation properties within the hydrocarbon sands with the correlation coefficients reaching 92% and 85%, respectively. By using seismic AVO inversion impedance, combining the application of the DI attribute and Vp/Vs ratio for lithology and fluid contents discrimination was conducted to improve the reservoir prediction accuracy in the field. Application results show that low values of the DI attribute (<18,000 m/s.g/cc) was indicative of hydrocarbon-filled sands effectively while Vp/Vs ratio presented a higher resolution in separating wet sand, dry-sand from shale. By using the linear regression relationship derived from cross-plotting analysis with well data, we calculated the volumes of porosity and water saturation from DI attribute and successfully screened out the hydrocarbon accumulation distribution, which reveals the potential zones of exploration interest in South Sumatra Basin.

Съдържание и износ на основни макроелементи с биомасата и зърното на ечемик (Hordeum Vulgare L.) отглеждан като последействие

A field study with spring barley (Hordeum vulgare L.) was conducted on the area of long-term balance experiment in Tsalapitsa village near Plovdiv (Bulgaria), on alluvial-meadow soil. Mineral fertilization was not applied to this crop in order to equalize the area regarding nutrient content. The crop grown before barley was maize with 4 variants of fertilization and one control variant: N0P0, N100Р50, N150Р100, N200Р150, and N250P200. The present study aimed to evaluate the productivity, content and uptake of macronutrients (N, P, K, Ca and Mg) with the biomass of barley, grown as aftereffect. Due to the fertilization of the previous crop, different residual amounts of nutrients in soil lead to significant variability in barley yields. The highest grain yield was obtained in variant N250P200 - 3978.8 kg/ha, approximately four times higher than the yield in the control. Nitrogen content in the grain of barley is also influenced by the variants, being the lowest in the control - 1.25%, and the highest in variants N250P200 and N200P150 - 2.13% and 2.09%, respectively. The variability of P, K, Ca and Mg contents by variants is lower. With the total biomass of barley, depending on the variants of the experiment, between 23.2 - 132.7 kg N/ha; 26.6 - 146.3 kg K/ha and 9.3 - 36.5 kg P/ha were exported from the field. A good regression relationship was found between barley grain yield and nitrogen export with the total biomass (R2 = 0.859, P≤0.001).

Bus Ride Index – a refined approach to evaluating road surface irregularities

The road surface quality can be assessed with ride comfort indices because of their strong correlation. Many studies on ride comfort have focused on cars and trucks, but their results are not applicable to buses, which are characterised by inherently different vehicle dynamics. In this study, a quarter-vehicle simulation concept was used to develop a Bus Ride Index (BRI) for evaluating the effect of road irregularities on bus ride comfort. A BRI model was developed to optimise ride comfort depending on seat configuration and air suspension and validated according to technical data. The results show a good regression relationship between BRI and the International Roughness Index (IRI). New IRI thresholds with regard to ride comfort and bus operating speeds were established to serve as a benchmark to develop better pavement maintenance strategies for bus lanes and to estimate road quality based on acceleration data.

Gamma-ray attenuation coefficients and transmission thickness of high consistency heavyweight concrete containing mineral admixture

In the study, high consistency heavyweight concrete mixtures containing barite aggregate were produced by using some common mineral admixtures (viscosity modifier, silica fume and fly ash) at various water/binder ratios and binder contents. Gamma-ray linear attenuation coefficients of the concrete mixtures were determined by using gamma sources of 137Cs and 60Co in NaI(Tl) gamma spectrometry system. The relationship between specimen thickness and transmission of the rays was constituted by emphasizing their mean free path, half-value layer, and tenth-value layer. Moreover, experimental mass attenuation coefficients of the concrete specimens were determined and compared with theoretical mass attenuation coefficients calculated by XCOM software depending on elemental fractions of these concrete in equivalent energies (662 keV, 1173 keV and 1332 keV). As a result, the replacement of the aforementioned admixtures with ordinary cement negatively affected the linear attenuation coefficients of the heavyweight concrete. A relative change of up to 25% was observed between the least and the highest attenuation thickness values at a certain gamma-ray transmission. A good regression relationship has been established between density and linear attenuation coefficients, density and mean free path, and density and half- or tenth-value layers of the heavyweight concrete. Theoretical (XCOM) mass attenuation coefficients were found similar to the experimental mass attenuation coefficients of the heavyweight concretes. Although there is a good linear regression relation between the theoretical and experimental mass attenuation coefficients at 662 keV energy of gamma rays, the relations were disappeared at 1173 and 1332 keV energies of gamma rays.

Detection and Quantification of Cannabinoids in Extracts of Cannabis sativa Roots Using LC-MS/MS.

A liquid chromatography-tandem mass spectrometry single-laboratory validation was performed for the detection and quantification of the 10 major cannabinoids of cannabis, namely, (-)-trans-Δ9-tetrahydrocannabinol, cannabidiol, cannabigerol, cannabichromene, tetrahydrocannabivarian, cannabinol, (-)-trans-Δ8-tetrahydrocannabinol, cannabidiolic acid, cannabigerolic acid, and Δ9-tetrahydrocannabinolic acid-A, in the root extract of Cannabis sativa. Acetonitrile : methanol (80 : 20, v/v) was used for extraction; d3-cannabidiol and d3- tetrahydrocannabinol were used as the internal standards. All 10 cannabinoids showed a good regression relationship with r2 > 0.99. The validated method is simple, sensitive, and reproducible and is therefore suitable for the detection and quantification of these cannabinoids in extracts of cannabis roots. To our knowledge, this is the first report for the quantification of cannabinoids in cannabis roots.

Research on Ultrasonic-Rebound-Strength Curve of Polypropylene Fiber Concrete in Chloride Environment

Exploring strength curve and the corrosion mechanism of polypropylene fiber reinforced cement in chloride environment by the ultrasonic-rebound method and wet-dry cycle method in the laboratory. And fitting actual strength with rebound value and ultrasonic velocity, the result indicates that compressive strength of polypropylene fiber reinforced cement has a good regression relationship with rebound value and supersonic velocity

Impact force for micro-detonation of striking arc machining of silicon nitrides using the Taguchi method

Impact force during the process of micro-detonation of striking arc machining (MDSAM) for silicon nitrides was investigated experimentally. Based on the generation principles, the orthogonal experimental design and regression analysis were employed to build the empirical model in order to understand the effects of processing parameters on impact force. It was demonstrated that for working current, working gas pressure and nozzle diameter of the micro-detonation generator, there were significant effects while for pulse width and working distance, there was hardly effect. In particular, the impact force decreased with working current and increased with working pressure and nozzle diameter. The exponential empirical model showed a good regression relationship between the processing parameters and impact force, which was verified by the experimental results. The present study could also present an important example to reveal the machining mechanism of MDSA and to provide a methodology for the control of MDSAM process.

Quantitative Analysis of Five Kudinosides in the Large‐leaved Kudingcha and Related Species from the Genus Ilex by UPLC–ELSD

The large-leaved Kudingcha from the genus Ilex, which is used as a traditional Chinese tea, contains several characteristic triterpenoid saponins that can be subjected to quality control evaluation. To develop and validate a rapid method incorporating reverse-phase ultra-performance liquid chromatography coupled with evaporative light scattering detection (UPLC-ELSD) for the simultaneous determination of the five triterpenoid saponins kudinoside L (1), kudinoside C (2), kudinoside A(3), kudinoside F(4) and kudinoside D(5) in several species of the large-leaved Kudingcha from the genus Ilex and 'Yerba Mate' (Ilex paraguariensis). The five compounds were separated using a water-acetonitrile mobile phase with a Waters Acquity BEH C(18)-column (100 × 2.1 mm, 1.7 µm). Separation took 13 min with detection and quantification limits ranging from 12.5 to 29.8 ng and 41.3 to 98.2 ng, respectively. The method was validated according to the regulatory guidelines with respect to precision, stability, repeatability and recovery. The triterpenoid saponins showed a good regression relationship (r(2) > 0.999) within the test ranges, and the recovery of the method was in the 95-105% range. The present method can be used successfully for the quality control of the large-leaved Kudingcha. The different Ilex species showed differences in distribution of the five triterpenoids. Ilex kudingcha, which makes up the major species of the large-leaved Kudingcha, contains the maximum amount of triterpenoid saponins.

Quantitative determination of four compounds and fingerprint analysis in the rhizomes of Drynaria fortunei (Kunze) J. Sm.

A rapid, sensitive, and accurate reversed-phase high-performance liquid chromatography with photodiode array detection method was developed for both quantitative determination of four compounds (caffeic acid-4-O-β-D-glucopyranoside, 5,7-dihydroxychromone-7-O-rutinoside, neoeriocitrin and naringin) and fingerprint analysis of the rhizomes of Drynaria fortunei (Kunze) J. Sm. The chromatographic separation was accomplished on an MZ-C18 column (4.6 × 250 mm, 5 μm) using gradient elution with acetonitrile and 0.02% aqueous acetic acid, at a flow rate of 1.0 mL min(-1), an operating temperature of 25°C, and a wavelength of 260 nm. The four compounds showed good regression relationship (R (2) > 0.9990) within linear ranges, and their recoveries were in the range of 98.11-102.23%. In the chromatographic fingerprint, thirteen common peaks were found and selected as characteristic peaks to assess the consistency of ten batches of the rhizomes of D. fortunei. The results indicate that the method of multiple compounds determination in combination with chromatographic fingerprint analysis is suitable for systematic quality evaluation of D. fortunei.

Studying the spatiotemporal variation of snow-covered days over China based on combined use of MODIS snow-covered days and in situ observations

Based on the moderate resolution imaging spectro-adiometer (MODIS)-acquired snow-covered days data (MSCD), validation of MSCD is performed by using 529 in situ observations of snow-covered days (SCD) from 2001 to 2006 in China. For the different characteristics of snow cover in four major snow-covered regions including the Tibetan Plateau, Xinjiang, and north-eastern and inner Mongolia, the validation process is divided into five parts for all of China. Our results indicate that except in the south-eastern part of the Tibetan Plateau, the MSCD is usually lower than the in situ SCD measurement. It is found that the MSCD have good polynomial regression agreement with the in situ measurements in Xinjiang and north-eastern and inner Mongolia with an R 2 values that reach 0.89, 0.78, and 0.87, respectively. Because the MSCD is smaller but with a good regression relationship with the in situ SCD, calibration of the MSCD images could significantly improve its precision in those regions. To be considered a stable snow-covered area, there must be greater than 60 days per year in which the pixels are covered by snow. Unstable snow-covered areas are ones in which fewer than 60 days but at least 1 day is covered by snow. The calibrated MSCD outcome indicates that the unstable snow-covered area can reach 555.2 × 104 km2, and the stable snow-covered area is approximately 273.1 × 104 km2. The area in the three major stable snow-covered regions of the Tibetan Plateau, Xinjiang, and north-eastern and inner Mongolia is approximately 100.4 × 104, 54.4 × 104, and 114.7 × 104 km2, respectively.

Chromatographic Fingerprint and Quantitative Analysis of Seven Bioactive Compounds ofScutellaria barbata

Scutellaria barbata D. Don is widely used as a folk antitumor and anti-inflammatory agent in Asia. However, a simple and global quality control method for S. barbata was lacking. In this study, six phenolic compounds, including P-coumaric acid, scutellarin, apigenin 5-O-β-glucopyranoside, luteolin, apigenin and 4'-hydroxywogonin were obtained from S. barbata by phytochemical investigations. The six compounds plus baicalein show cytotoxcities to the nine human cancer cells, K562, MGC-803, HL60, SH-SY5Y, SW1116, SMMC-7221, SW480, HepG2 and KB. Subsequently, a high-performance liquid chromatography with photodiode array detector (HPLC-DAD) was developed for both fingerprint analysis of S. barbata and quantitative determination of the seven anticancer active compounds in S. barbata. The chromatographic separation was accomplished on an Ultimate™ XB-C18 column (4.6 x 250 mm, 5 µm) in 65 min. For fingerprinting, 26 common peaks were found and selected as characteristic peaks to assess the consistency of S. barbata samples. For quantitative analysis, the seven bioactive compounds showed good regression relationship ( R² > 0.999) within test ranges and the recovery of the method was in the range of 90-105 %. In brief, the present study provides the fingerprint analysis and quantitative methods for global and systematical quality control of S. barbata for its anticancer usage.

Mechanisms of Remote-Sensing Reflectance Variability and Its Relation to Bio-Optical Processes in a Highly Turbid Eutrophic Lake: Lake Taihu (China)

During November 2006 and November 2007, two field bio-optical campaigns were conducted in Lake Taihu to assess the mechanisms regulating the water-color variability in a typically inland eutrophic lake. Various bio-optical parameters were acquired simultaneously with measurements of remote-sensing reflectance ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rs</sub> ), which generates a collection of 106 samples. The bio-optical parameters span a wide range of variability indicating the presence of complex water-column conditions, which also correspondingly brings about a great variability of the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rs</sub> ( ¿) spectra. The <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rs</sub> (¿) variability characteristics are extracted by an empirical orthogonal-function (EOF) analysis. The results show that 84% of the total variance of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rs</sub> (¿) is mainly attributed to particulate absorption (particularly chlorophyll a (Chl a) absorption) and pure-water absorption, which has been summarized as the first EOF mode, <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> , and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> can mainly reflect the other variance of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rs</sub> (¿), which can be attributed entirely to phytoplankton: absorption by pigments and scattering by particles. Further, the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rs</sub> (¿) spectra are categorized into two types by a hierarchical cluster approach, that is, a universal type and a phytoplankton-dominant type. The phytoplankton-dominant stations are characterized by high Chl a concentration, organic suspended-matter concentrations, and phytoplankton absorption ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ph</sub> ) with a good regression relationship between <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rs</sub> (700) and Chl a concentration ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.922), while the universal stations present the wider variation ranges of particulate scattering ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</sub> ) and backscattering ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bp</sub> ) due to the great inorganic suspended-matter concentration variation.