an important property that has been extensively studied in quantitative structure activityrelationship (qsar) is the chromatographic retention index. qsar study is suggested for theprediction of retention index of alkanes and alkenes compounds. modeling of the retention indexof alkanes and alkenes compounds as a function of molecular structures was established bydifferent chemometrics methods. ...

to study the effects of soil amendments on physical and hydraulic properties of a saline-sodic sandy clay loam soil, a field experiment was carried out as a complete block design with three replications. the treatments in this research consisted of control (b), 10 ton ha-1 gypsum (g), 10 ton ha-1 urban solid compost (c), three levels of vinyl alcohol acrylic acid (s1= 0.05%, s2= 0.1%, s3= 0.2%)...

An important property that has been extensively studied in quantitative structure activityrelationship (QSAR) is the chromatographic retention index. QSAR study is suggested for theprediction of retention index of alkanes and alkenes compounds. Modeling of the retention indexof alkanes and alkenes compounds as a function of molecular structures was established bydifferent chemometrics methods. ...

A method was developed to employ National Institute of Standards and Technology (NIST) 2008 retention index database information for molecular retention matching via constructing a set of empirical distribution functions (DFs) of the absolute retention index deviation to its mean value. The effects of different experimental parameters on the molecules' retention indices were first assessed. The...

An expert system is described that proposes an optimal mobile phase composition in reversed-phase high-performance liquid chromatography. This is achieved by predicting the retention index of the compound of interest from fragmental constants. Using a calibration line, set up with reference compounds, it is possible to infer from the retention index the percentage of organic modifier in the mob...

soil quality is a necessary indicator of land management. different indices are applied to evaluate farming systems, soil types and land uses based on soil quality. the slope of retention curve at its inflection point has been defined as soil physical quality index (si) but the relationships between si and penetration resistance (pr), the least limiting water range (llwr), and available water c...