Spectral analysis of gilgai soil

Soil Research ◽  
1977 ◽  
Vol 15 (3) ◽  
pp. 191 ◽  
Author(s):  
R Webster
Keyword(s):  
Spectral Analysis ◽  
Moving Average ◽  
Block Size ◽  
Principal Component ◽  
Chloride Content ◽  
Soil Morphology ◽  
Data Logger ◽  
South Wales ◽  
Rate Of Increase

Spatial variation in gilgai soil mas studied on a transect across typical gilgai terrain of the Bland Plain of New South Wales. The soil was sampled at 4 m intervals over a distance of 1.5 km at Caragabal (33�50�S, 147�40�E). Soil morphology was recorded to 1 m and samples taken for laboratory determination of pH, electrical conductivity and chloride content from 0-10, 30-40 and 80-90 cm. Bulk density was determined for the 0-10 cm depth also. All soil properties, when graphed against their sampling positions, appear very erratic; but when filtered by a five-point moving average show recurrent short range variation, associated to some extent with the visible elements of the gilgai pattern. Block variance increases steadily with increasing block size to approximately 32 m for conductivity, pH at 80-90 cm, colour hue and chroma, depth to gypsum and the first principal component. Thereafter the rate of increase is less. Spectral densities were computed from correlograms for each property. Spectra for the properties above showed more or less strong peaks at 0.12 cycles, equivalent to a wavelength of 33.3 m. Gilgai evidently recurs sufficiently regularly on the transect for spectral analysis to reveal a periodicity, and the technique is judged to be sufficiently sensitive for analysing records made directly by data logger.

An examination of some acid soils at Batlow, New-South-Wales

Soil Research ◽  
1993 ◽  
Vol 31 (4) ◽  
pp. 437 ◽  
Author(s):  
IP Little
Keyword(s):  
Acid Soils ◽  
Principal Component ◽  
Apple Fruit ◽  
Exchange Capacity ◽  
Soil Survey ◽  
South Wales ◽  
Exchangeable Ca ◽  
Exchangeable Al ◽  
Clay Suspensions

This paper has two components. Firstly it evaluates a set of data for the apple-growing soils of the Batlow district. Secondly it makes some comments on the use of silver thiourea for the determination of exchangeable Al and Mn and the estimation of exchangeable Al by titration of 1 M KCl suspensions. A group of 21 profiles from soils used for apple-growing in the Batlow District were examined in the laboratory. It was found that many of the soils were very acidic, especially in the subsoil. Dilute CaCl2 extracted as much as 50 �g g-1 of Al and considerable exchangeable Al was extracted by silver thiourea. Exchangeable Ca levels were usually adequate for plant growth, hence low levels in apple fruit may reflect the adverse effect of Al on Ca uptake by the plant. Potassium levels were low and may be marginal in some cases and Mg tended to be low in the surface. Principal component analysis showed 77% of the variation in the data was accounted for by three independent components, one involving pH, exchangeable Ca and Al, one involving K and Mg and one involving exchangeable Mn. It was demonstrated that silver thiourea does not replace Al as effectively as the basic exchangeable cations. Also, thiourea reduces Mn so that low values will be obtained for exchangeable Al in soils with much easily reducible Mn because of the increase in pH that accompanies reduction. Silver thiourea appears to overestimate exchangeable Al in some soils with very low cation exchange capacity. Titration of clay suspensions in 1 M KCl is a satisfactory and reliable way of measuring exchangeable Al that also enables an assessment of pH-dependent charge. The method used by the USDA Soil Survey Staff, viz. equilibration of soil samples with 1 M KCl for 16 h, filtration, and determination of Al also gives reproducible results and is taken as the standard. Successive leaching with portions of 1 M KCl tends to give low values for exchangeable Al.

Characterization of Impressed Current Technique to Model Corrosion of Reinforcement in Concrete

2020 ◽  
Vol 11 (1) ◽  
pp. 93-99
Author(s):  
Abu Zakir Morshed ◽  
Sheikh Shakib ◽  
Tanzim Jahin
Keyword(s):  
Immersion Time ◽  
Chloride Content ◽  
Engineering Science ◽  
Coastal Regions ◽  
Faraday’S Law ◽  
Current Technique ◽  
Corrosion Cell ◽  
Impressed Current

Corrosion of reinforcement is an important durability concern for the structures exposed to coastal regions. Since corrosion of reinforcement involves long periods of time, impressed current technique is usually used to accelerate the corrosion of reinforcement in laboratories. Characterization of impressed current technique was the main focus of this research,which involved determination of optimum chloride content and minimum immersion time of specimens for which the application of Faraday’s law could be efficient. To obtain optimum chloride content, the electrolytes in the corrosion cell were prepared similar to that of concrete pore solutions. Concrete prisms of 200 mm by 200 mm by 300 mm were used to determine the minimum immersion time for saturation. It was found that the optimum chloride content was 35 gm/L and the minimum immersion time for saturation was 140 hours. Accounting the results, a modified expression based on Faraday’s law was proposed to calculate weight loss due to corrosion. Journal of Engineering Science 11(1), 2020, 93-99

Research on Supply and Demand of Xi'an Real Estate Market

2011 ◽  
Vol 368-373 ◽  
pp. 3078-3082
Author(s):  
Zhou Ji Meng ◽  
Tao Zhou ◽  
Shu Hua Gao
Keyword(s):  
Principal Component Analysis ◽  
Spectral Analysis ◽  
Real Estate ◽  
Spectral Density ◽  
Supply And Demand ◽  
Principal Component ◽  
Real Estate Market ◽  
Medium Term ◽  
Real Estate Price ◽  
Synthetic Indicators

In the passage, the indicators of supply and demand of real estate market in Xi'an are established, and such indicators are synthesized into a class of synthetic indicators using “principal component analysis”. After the spectral analysis of synthetic indicators, periodic change of supply and demand of real estate through spectral density could be determined. Through the analysis, great randomness existed in supply and demand of real estate in Xi’an. Furthermore, in the medium term, a 3.3 years’ secondary cycle still existed in synthetic indicators of demand, while randomness existed in synthetic indicators of supply. Such findings suggest a declined trend existed in real estate price in medium term of Xi’an.

scholarly journals Application of Derivative, Derivative Ratio, and Multivariate Spectral Analysis and Thin-Layer Chomatography-Densitometry for Determination of a Ternary Mixture Containing Drotaverine Hydrochloride, Caffeine, and Paracetamol

2007 ◽  
Vol 90 (2) ◽  
pp. 391-404 ◽  
Author(s):  
Fadia H Metwally ◽  
Yasser S El-Saharty ◽  
Mohamed Refaat ◽  
Sonia Z El-Khateeb
Keyword(s):  
Thin Layer ◽  
Least Squares ◽  
Ternary Mixture ◽  
Principal Component Regression ◽  
Pharmaceutical Preparations ◽  
Principal Component ◽  
Standard Addition ◽  
Drotaverine Hydrochloride ◽  
Assay Precision

Abstract New selective, precise, and accurate methods are described for the determination of a ternary mixture containing drotaverine hydrochloride (I), caffeine (II), and paracetamol (III). The first method uses the first (D1) and third (D3) derivative spectrophotometry at 331 and 315 nm for the determination of (I) and (III), respectively, without interference from (II). The second method depends on the simultaneous use of the first derivative of the ratio spectra (DD1) with measurement at 312.4 nm for determination of (I) using the spectrum of 40 μg/mL (III) as a divisor or measurement at 286.4 and 304 nm after using the spectrum of 4 μg/mL (I) as a divisor for the determination of (II) and (III), respectively. In the third method, the predictive abilities of the classical least-squares, principal component regression, and partial least-squares were examined for the simultaneous determination of the ternary mixture. The last method depends on thin-layer chromatography-densitometry after separation of the mixture on silica gel plates using ethyl acetatechloroformmethanol (16 + 3 + 1, v/v/v) as the mobile phase. The spots were scanned at 281, 272, and 248 nm for the determination of (I), (II), and (III), respectively. Regression analysis showed good correlation in the selected ranges with excellent percentage recoveries. The chemical variables affecting the analytical performance of the methodology were studied and optimized. The methods showed no significant interferences from excipients. Intraday and interday assay precision and accuracy values were within regulatory limits. The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparations. The validity of the proposed methods was further assessed by applying a standard addition technique. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the manufacturer's method.

Multivariate Analysis Aided Surface-Enhanced Raman Spectroscopy (MVA-SERS) Multiplex Quantitative Detection of Trace Fentanyl in Illicit Drug Mixtures Using a Handheld Raman Spectrometer

2021 ◽  
pp. 000370282110329
Author(s):  
Ling Wang ◽  
Mario O. Vendrell-Dones ◽  
Chiara Deriu ◽  
Sevde Doğruer ◽  
Peter de B. Harrington ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Principal Component ◽  
Surface Enhanced Raman Spectroscopy ◽  
Quantitative Detection ◽  
Least Squares Regression ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Detection ◽  
Current Screening

Recently there has been upsurge in reports that illicit seizures of cocaine and heroin have been adulterated with fentanyl. Surface-enhanced Raman spectroscopy (SERS) provides a useful alternative to current screening procedures that permits detection of trace levels of fentanyl in mixtures. Samples are solubilized and allowed to interact with aggregated colloidal nanostars to produce a rapid and sensitive assay. In this study, we present the quantitative determination of fentanyl in heroin and cocaine using SERS, using a point-and-shoot handheld Raman system. Our protocol is optimized to detect pure fentanyl down to 0.20 ± 0.06 ng/mL and can also distinguish pure cocaine and heroin at ng/mL levels. Multiplex analysis of mixtures is enabled by combining SERS detection with principal component analysis and super partial least squares regression discriminate analysis (SPLS-DA), which allow for the determination of fentanyl as low as 0.05% in simulated seized heroin and 0.10% in simulated seized cocaine samples.

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