scholarly journals The primordial chondritic nature and large-scale heterogeneities in the mantle: evidence from high and low partition coefficient elements in oceanic basalts

1980 ◽  
Vol 297 (1431) ◽  
pp. 203-213 ◽  
Keyword(s):  
Partition Coefficient ◽  
Partial Melting ◽  
Partition Coefficients ◽  
Large Scale ◽  
Chemical Properties ◽  
Physico Chemical ◽  
Mantle Sources ◽  
Oceanic Basalts ◽  
The Difference ◽  
Solid Liquid

Large-scale heterogeneities in the mantle are investigated through trace elements measured in oceanic basalts from different locations in the Atlantic and Pacific oceans. The study relies upon the physico-chemical properties of the elements and their classification according to their partition coefficients. High partition coefficient elements (Co, Ni, Cr) have concentrations in peridotite that are not sensitive to solid-liquid equilibrium (partial melting); the mantle should therefore be homogeneous with respect to these elements. The ratios of elements that have equal or very similar low partition coefficients (Y/Tb, Zr/Hf and Nb/Ta) are constant in all samples studied, despite their large concentration range. These ratios are equal to chondritic ratios and favour a chondritic nature for the primordial mantle. The La/Ta ratio shows two values, either 9 or 18, which are closely related to topography (9 for topographic highs). When the difference between partition coefficients of two hygromagmaphilic elements increases, the local variations observed for their ratio can be interpreted either as local heterogeneities of mantle sources or as the effect of magmatic processes (e.g. partial melting).

scholarly journals Exploring the difference in xerogels and organogels through in situ observation

2018 ◽  
Vol 5 (1) ◽  
pp. 170492
Author(s):  
Binglian Bai ◽  
Zhiming Li ◽  
Haitao Wang ◽  
Min Li ◽  
Yukihiro Ozaki ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Fluorescence Spectra ◽  
Chemical Properties ◽  
Columnar Structure ◽  
In Situ Observation ◽  
Physico Chemical ◽  
Aggregation Structure ◽  
Ft Ir ◽  
The Difference

Solvent–gelator interactions play a key role in mediating organogel formation and ultimately determine the physico-chemical properties of the organogels and xerogels. The ethanol organogels of 1,4-bis[(3,4,5-trihexyloxy phenyl)hydrazide]phenylene (TC6) were investigated in situ by FT-IR, Raman and fluorescence spectra, and XRD, and it was confirmed that the intermolecular interaction and aggregation structure of TC6 ethanol organogels were quite different from those of xerogels. Simultaneously, unprecedented phase transition from organogel to suspension upon heating was observed in ethanol organogel, and the suspension phase exhibited lytropic liquid crystalline behaviour with a rectangular columnar structure. This study may open the possibility to design new gelators with a new dimension of versatility.

Partitioning of unsubstituted Polycyclic Aromatic Hydrocarbons between surface sediments and the water column in the Brisbane River Estuary

1990 ◽  
Vol 41 (4) ◽  
pp. 443 ◽  
Author(s):  
SI Kayal ◽  
DW Connell
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Water Column ◽  
Aromatic Hydrocarbons ◽  
Partition Coefficients ◽  
Laboratory Experiments ◽  
River Estuary ◽  
Chemical Properties ◽  
Linear Relationships ◽  
Physico Chemical ◽  
Polycyclic Aromatic

In all, 23 sediment samples and 8 water column samples from the Brisbane River estuary, Queensland, Australia, were analysed for polycyclic aromatic hydrocarbons (PAHs) in order to assess the field partitioning behaviour of these hydrocarbons. Twelve PAHs, ranging in molecular weight from naphthalene to benzo[a]pyrene, were identified and quantified. Their partition coefficients, indexed to sediment organic carbon and lipid content, were calculated after filtering to remove particulates and making a calculated adjustment for colloids, or organic matter, in the water phase. In logarithmic form, the partition coefficients were related to the physico-chemical properties of the compounds (Kow, Sw, RRT) by relationships having a parabolic shape rather than being linear. However, compounds with log Kow values of less than 5.5 gave linear relationships comparable to, but distinctly different from, those obtained from laboratory experiments. It is suggested that field conditions have distinctive differences from laboratory experiments that do not allow the direct translation of laboratory-based relationships to the natural aquatic environment.

scholarly journals Application of lipophilicity parameters in QSRR analysis of newly synthesized s-triazine derivatives: Prediction of the retention behavior

2011 ◽  
Vol 65 (5) ◽  
pp. 533-540 ◽  
Author(s):  
Lidija Jevric ◽  
Bratislav Jovanovic ◽  
Sonja Velimirovic ◽  
Aleksandra Tepic ◽  
Gordana Koprivica ◽  
...  
Keyword(s):  
Partition Coefficients ◽  
Structural Parameters ◽  
Chemical Properties ◽  
Reversed Phase ◽  
Retention Behavior ◽  
Chemical Screening ◽  
Physico Chemical ◽  
Agricultural Chemistry ◽  
Triazine Derivatives ◽  
Coefficient Measurement

Considerable attention has been paid to the analysis of chemicals in the s-triazine group, due to their widespread use in agricultural chemistry and their subsequent impact on biological systems. For initial chemical screening of the activity of newly synthesized compounds, it is recommended to determine their lipophilicity and physico-chemical property in relation to biological activity. Lipophilicity is difficult to quantify. The most widely accepted measure of lipophilicity is the octanol-water partition coefficient. Measurement of the octanol-water partition coefficients is achieved by an alternative method, i.e. reversed-phase liquid chromatography. Reversed-phase thin-layer chromatography (RP TLC) is a rapid method for the analysis of large number of s-triazine type compounds. Certain relationship between the structure of s-triazine compounds and their mobility on silica gel impregnated with paraffin oil have recently been demonstrated. The retention behavior of compounds in various chromatographic systems strongly depends on their physico-chemical properties. Recently, much effort was given in finding adequate mathematical model relating the retention of the given analyte to its physico-chemical and structural parameters (descriptors). These correlations are known as quantitative structure-retention relationships (QSRR), which offer a powerful tool for the prediction of separation behavior. The QSRR equations describing retention constants RM0, determined for different modifiers in mobile phase in terms of logarithms of n-octanol-water partition coefficients, were derived. The partition coefficients (AlogPs, AClogP, AB/logP, milogP, AlogP, MlogP, logPKowin, XlogP2, XlogP3, ACDlogP i ClogP) were calculated by application of different software packages. The goal of this paper was to select the logP data and TLC system that best characterize octanol/water partitioning and thus the lipophilicity of the investigated molecules.

scholarly journals Study of the Antibacterial and Antioxidant Capacities of Fixed Oil of Moringa oleifera L. Cultivated in the Southwest of Algeria

2021 ◽  
Author(s):  
A. Boulal ◽  
A. Ouafiane ◽  
M. Oubiri ◽  
S. Ladjel
Keyword(s):  
Moringa Oleifera ◽  
Chemical Properties ◽  
Fatty Acid Analysis ◽  
International Standards ◽  
Antioxidant Power ◽  
Physico Chemical ◽  
Therapeutic Properties ◽  
Moringa Oleifera Oil ◽  
Solid Liquid

Background: Since time immemorial, humans have always been interested in lipids for various uses, namely food, cosmetology, medicine, etc. Many seeds, sources of oils, are increasingly studied for their nutritional and therapeutic properties. Methods: The present study aims to valorize the vegetable oil obtained from the seeds of the Moringa oleifera plant widely cultivated in the southwest of Algeria, using the solid-liquid extraction technique. In addition, the fatty acid analysis of this oil, using the gas chromatography technique. Result: An oil yield of 30.43% was obtained, revealed that it contains ten different compounds. The characterization of the oil obtained (physico-chemical properties such as organoleptic properties, density, viscosity, refractive index) proved to comply with international standards and AFNOR standards. In addition, it turned out that Moringa oleifera oil has a very interesting antioxidant power. However, this oil did not show any antibacterial activity on the strains tested.

scholarly journals Highly Efficient Nanocarbon Coating Layer on the Nanostructured Copper Sulfide-Metal Organic Framework Derived Carbon for Advanced Sodium-Ion Battery Anode

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1324 ◽  
Author(s):  
Chiwon Kang ◽  
Yongwoo Lee ◽  
Ilhwan Kim ◽  
Seungmin Hyun ◽  
Tae Hoon Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Copper Sulfide ◽  
Large Scale ◽  
Metal Organic Framework ◽  
Specific Capacity ◽  
Chemical Properties ◽  
Sodium Ion ◽  
Physico Chemical ◽  
Metal Organic ◽  
Organic Framework

High theoretical capacity and low-cost copper sulfide (CuxS)-based anodes have gained great attention for advanced sodium-ion batteries (SIBs). However, their practical application may be hindered due to their unstable cycling performance and problems with the dissolution of sodium sulfides (NaxS) into electrolyte. Here, we employed metal organic framework (MOF-199) as a sacrificial template to fabricate nanoporous CuxS with a large surface area embedded in the MOF-derived carbon network (CuxS-C) through a two-step process of sulfurization and carbonization via H2S gas-assisted plasma-enhanced chemical vapor deposition (PECVD) processing. Subsequently, we uniformly coated a nanocarbon layer on the Cu1.8S-C through hydrothermal and subsequent annealing processes. The physico-chemical properties of the nanocarbon layer were revealed by the analytical techniques of high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). We acquired a higher SIB performance (capacity retention (~93%) with a specific capacity of 372 mAh/g over 110 cycles) of the nanoporous Cu1.8S-C/C core/shell anode materials than that of pure Cu1.8S-C. This encouraging SIB performance is attributed to the key roles of a nanocarbon layer coated on the Cu1.8S-C to accommodate the volume variation of the Cu1.8S-C anode structure during cycling, enhance electrical conductivity and prevent the dissolution of NaxS into the electrolyte. With these physico-chemical and electrochemical properties, we ensure that the Cu1.8S-C/C structure will be a promising anode material for large-scale and advanced SIBs.

Strain Energy and Behaviour of Overconsolidated Soils

1967 ◽  
Vol 4 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Elmer W Brooker
Keyword(s):  
Mechanical Properties ◽  
Strain Energy ◽  
Large Scale ◽  
Chemical Properties ◽  
Earth Pressure ◽  
Quantitative Evidence ◽  
Physico Chemical ◽  
Overconsolidated Clays ◽  
Overconsolidated Soils

Bjerrum recently presented a strain energy hypothesis which explains qualitatively the behaviour of overconsolidated clays and the phenomena of long-term slope failures in these soils. Quantitative evidence, gathered from a series of large-scale consolidation tests, is presented here which supports the strain energy hypothesis. The coefficient of earth pressure at rest was found to be a function of strain energy at a given value of OCR. It is also shown that the degree of disintegration of overconsolidated soils during a slaking test is related to strain energy. It is inferred from the results that mineralogy and the capacity of a soil to adsorb strain energy are related. The evidence suggests that certain physico-chemical properties may be quantitatively related to mechanical properties through the concept of strain energy.

scholarly journals Study of physico-chemical properties of potential beta-adrenolytics

2014 ◽  
Vol 61 (2) ◽  
pp. 49-54
Author(s):  
M. Stankovičová ◽  
Ž. Bezáková ◽  
P. Mokrý ◽  
P. Salát ◽  
M. Kočík ◽  
...  
Keyword(s):  
Partition Coefficients ◽  
Spectral Characteristics ◽  
Chemical Properties ◽  
Side Chain ◽  
Log P ◽  
Structure Activity ◽  
Physico Chemical ◽  
The Relationship ◽  
Layer Chromatography ◽  
Derivatives Of

Abstract The aim of this paper is the study of physico-chemical properties of the chosen compounds, derivatives of 2-hydroxy-3-[2-(4-methoxyphenyl) ethylamino]propyl-4-[(alkoxycarbonyl)amino]benzoates and 2-hydroxy-3-[2-(2-methoxyphenyl)ethylamino]propyl-4-[(alkoxycarbonyl) amino]benzoates with potential ultra-short beta-adrenolytic activity. The studied compounds are different in the position of the substituent on the benzene ring in the side chain as well as in the aromatic ring in position 4 with alkyl- (methylto butyl-) carbamate. The physico-chemical characteristics, for example, lipophilicity, surface activity, adsorbability, acidobasic properties etc., are very important for the explanation of the relationship between structure and biological activity of the drug. These parameters serve as the base of quantitative structure-activity study. The goal of this work is to establish the spectral characteristics of studied compounds in UV-area, pKa values, the parameters of lipophilicity (the values of Rf and RM from thin layer chromatography, retention time t´R and capacity factor k´ from liquid chromatography and experimental partition coefficients log P´ values), surface tension, critical micelle concentrations, the adsorbability of compounds expressed by percent of adsorbed compound on active charcoal β% as well as by Freundlich adsorption isotherms. The obtained values are correlated with the parameters characterising the size of molecule, for example, the number of carbon atoms on carbamate functional group.

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