scholarly journals Peculiarities of acid-base properties of peat formed in various agroclimatic zones of the Altai mountainous region

2021 ◽  
Vol 928 (1) ◽  
pp. 012003
Author(s):  
G V Larina ◽  
E V Kaigorodov ◽  
E B Daibova ◽  
O A Yalbacheva ◽  
L G Vidyaykina
Keyword(s):  
Chemical Properties ◽  
Base Saturation ◽  
Degree Of Saturation ◽  
Regression Equations ◽  
Mountainous Region ◽  
Acid Base ◽  
Raised Bog ◽  
Exchangeable Acidity ◽  
Physico Chemical ◽  
Agroclimatic Zones

Abstract The results of the study of acid-base indicators of peat in the Altai mountainous region are presented. The natural factors that in the aggregate determine the peculiarities of the physico-chemical properties of mountain peat of different agro-climatic zones of the Altai Mountains have been revealed. The variation in the acid values, total absorbed bases, adsorption capacity and the degree of saturation of raised-bog, transitional, fen peat, the number of exchangeable ions Ca2+ and Mg2+ has been estimated. The interrelation among these indicators has been presented. For the first time, regression equations of the relationship between exchangeable acidity pHKC1 and the degree of peat base saturation V, between total absorbed bases S and the degree of peat base saturation V have been obtained using nonlinear regression analysis. The adequacy and stability of the developed models have been verified. The calculated mean errors of approximation of regression models characterise the high accuracy of the forecast and are indicative of a good selection of models for the initial data.

Acute Inhalation Toxicity of Some Halogenated and Non-halogenated Hydrocarbons

1982 ◽  
Vol 1 (3) ◽  
pp. 239-247 ◽  
Author(s):  
D.G. Clark ◽  
D.J. Tinston
Keyword(s):  
Chemical Properties ◽  
Degree Of Saturation ◽  
Halogenated Hydrocarbons ◽  
Inhalation Toxicity ◽  
Saturated Vapour Pressure ◽  
Physico Chemical ◽  
Wide Range ◽  
The Central Nervous System ◽  
Thermodynamic Scale ◽  
Rat Cns

1 The relative potency of effect of a wide range of halogenated and unsubstituted hydrocarbons on the central nervous system (CNS) and the heart of experimental animals have been determined. 2 The chemicals used caused either stimulation or depression of the rat CNS after 10 minutes' inhalation of concentrations ranging from 0.24% to > 80% (v/v), and cardiac sensitization in dogs after 5 minutes' inhalation of 0.12% to approximately 80% (v/v). 3 The toxicity could not be correlated with chemical structure, molecular weight, the presence or absence of various halogen atoms or the degree of saturation, but it was inversely related to the saturated vapour pressure. When the results were expressed on a thermodynamic scale the chemicals had similar potencies at relative saturations of 0.004 to 0.04 4 It is suggested that the effects of these chemicals on the CNS and the heart are probably structurally non-specific, and the chemicals may be regarded as physical toxicants whose effects are predictable from their physico-chemical properties.

scholarly journals A new approach in topological descriptors usage. Iterated line graphs in the theoretical prediction of physico-chemical properties of saturated hydrocarbons

2019 ◽  
Keyword(s):  
Boiling Point ◽  
Molecular Graph ◽  
Chemical Properties ◽  
Topological Descriptors ◽  
Vaporization Enthalpy ◽  
Line Graphs ◽  
Regression Equations ◽  
Saturated Hydrocarbons ◽  
Program Complex ◽  
Physico Chemical

A new look on the problem of the molecular systems index description is presented. The capabilities of iterated line (edge) graphs in characterization of saturated hydrocarbons properties were investigated. It was demonstrated that single selected molecular (graph-theoretical (topological) or informational) descriptor calculated for the sequence of nested line graphs provides quite reliable progressive set of regression equations. Hence, the problem of descriptor set reduction is solved in the presented approach at list partially. Corresponding program complex (QUASAR) has been implemented with Python 3 program language. As the test example physico-chemical properties of octane isomers have been chosen. Among the properties under investigation there are boiling point, critical temperature, critical pressure, enthalpy of vaporization, enthalpy of formation, surface tension and viscosity. The corresponding rather simple linear regression equations which include one, two or three parameters correspondingly have been obtained. The predictive ability of the equations has been investigated using internal validation tests. The test by leave-one-out (LOO) validation and Y‑scrambling evaluate the obtained equations as adequate. For instance, for the regression model for boiling point the best equation characterizes by determination coefficients R2 = 0.943, with LOO procedure – Q2 = 0.918, while for the Y-scrambling test Q2y-scr<0.3 basically. It is shown that all the abovementioned molecular properties in iterated line graph approach can be effectively described by commonly used topological indices. Namely almost every randomly selected topological index can give adequate equation. Effectiveness is demonstrated on the example of Zagreb group indices. Also essential effectiveness and rather universal applicability of the so-called “forgotten” index (ZM3) was demonstrated.

scholarly journals Influence of fire on selected physico-chemical properties of forest soil

2019 ◽  
Vol 70 (1) ◽  
pp. 39-43
Author(s):  
Małgorzata Majder-łopatka ◽  
Wiesław Szulc ◽  
Beata Rutkowska ◽  
Dominik Ptasiński ◽  
Witold Kazberuk
Keyword(s):  
Organic Carbon ◽  
Chemical Properties ◽  
Test Material ◽  
Soil Profiles ◽  
Exchangeable Acidity ◽  
Physico Chemical ◽  
Negative Effect ◽  
Physical And Chemical ◽  
Nitrogen Contents ◽  
And Chemical Properties

Abstract The aim of the research was to determine whether, and to what extent, a surface fire of forest areas determines changes in physical and chemical properties of the soil. The test material consisted of soil samples taken from soil profiles exposed in a burnt-out area and in an area unaffected by fire. The samples were analyzed for total organic carbon and total nitrogen contents, and also selected indicators of soil acidification. As a result of the tests, it was found that there was a decrease in the levels of organic carbon (by over 75%) and nitrogen (by 50%). A negative effect of the changes was the narrowing of the C/N ratio, a positive one – an increase in soil pH (from 3.14 to 4.67), and a several-times reduction in hydrolytic and exchangeable acidity.

Structural and physico-chemical properties of insoluble rice bran fiber: effect of acid–base induced modifications

RSC Advances ◽  
2015 ◽  
Vol 5 (97) ◽  
pp. 79915-79923 ◽  
Author(s):  
Jing Qi ◽  
Wallace Yokoyama ◽  
Kingsley George Masamba ◽  
Hamid Majeed ◽  
Fang Zhong ◽  
...  
Keyword(s):  
Rice Bran ◽  
Chemical Properties ◽  
Acid Base ◽  
Physico Chemical

Various acid–base regimes induced structural and physicochemical modifications of IRBF.

Investigation of the effect of cucurbit[7]uril complexation on the photophysical and acid–base properties of the antimalarial drug quinine

2016 ◽  
Vol 18 (44) ◽  
pp. 30520-30529 ◽  
Author(s):  
Suman Mallick ◽  
Kaushik Pal ◽  
Falguni Chandra ◽  
Apurba L. Koner
Keyword(s):  
Antimalarial Drug ◽  
Chemical Properties ◽  
Acid Base ◽  
Physico Chemical ◽  
Base Properties

Tuning the physico-chemical properties of an anti-malarial drug upon cucurbit[7]uril encapsulation.

scholarly journals Soil Factors are the Drivers for Wetlands Colonization by Pneumatopteris afra in Nigeria

2021 ◽  
Vol 50 (2) ◽  
pp. 351-360
Author(s):  
Akomolafe Gbenga Festus ◽  
Rahmad Zakaria
Keyword(s):  
Diversity Index ◽  
Chemical Properties ◽  
Exchange Capacity ◽  
Shannon Index ◽  
Community Characteristics ◽  
Soil Factors ◽  
Exchangeable Acidity ◽  
Shannon Diversity ◽  
Physico Chemical ◽  
Direct Ordination

The relationships between soil factors and plant community characteristics of some wetlands invaded by Pneumatopteris afra and non-invaded ones were investigated. Sixty soil samples were obtained from six wetlands comprising three invaded and three non-invaded in Lafia, Nigeria using sixty quadrants arranged on six 200 m transects. The samples, after air-dried and sieved using 2 mm mesh were analysed for the physico-chemical properties which include pH, organic matter (OM), percentage nitrogen (% N), phosphorus (P), calcium (Ca), sodium (Na), potassium (K), magnesium (Mg), exchangeable acidity (EA), percentage base saturation (% BS), particle size, porosity, bulk density (BD), hydraulic conductivity (HC), and moisture content (MC) using standard methods. Direct ordination in canonical correspondence analysis was used to determine the influence of these soil factors on P. afra abundance, Shannon diversity, and species richness of both invaded and non-invaded sites. All sites differ from each other in terms of their physico-chemical parameters. The invaded sites appeared to be more acidic (pH = 3.22), less sandy, more porous (38.11%), low HC (1.23) as compared with non-invaded ones. Soil factors that favoured abundance of P. afra(% OM and EA) correlated negatively with Shannon diversity index of invaded sites which was positively influenced by % N, pH, and cation exchange capacity (CEC). At the non-invaded sites, Shannon index and density were influenced positively by % BS, pH, AP, and % N. All these observations showed that the soil factors played significant roles in the establishment of P. afra at the invaded sites, and also on the plant diversity at non-invaded sites.

scholarly journals Physico-chemical properties of N-(2-Hydroxybenzoyl)-N'-(p-Tosil) Hydrazine

2021 ◽  
Vol 11 (1) ◽  
pp. 71-81
Author(s):  
Yulia B. Elchishcheva ◽  
◽  
Ksenia S. Gorbunova ◽  
Petr T. Pavlov ◽  
◽  
...  
Keyword(s):  
Dissociation Constants ◽  
Hydrolytic Stability ◽  
Chemical Properties ◽  
Alkaline Media ◽  
Acid Dissociation ◽  
Degree Of Hydrolysis ◽  
Acid Base ◽  
Acid Dissociation Constants ◽  
Physico Chemical ◽  
Over Time

The results of a study of the physicochemical properties of N- (2-hydroxybenzoyl) -N '- (p-tosyl) hydrazine (GBSH) are presented. The solubility of the reagent in ethanol, 0.1 mol / L KOH solution, toluene, chloroform, hexane was studied by spectrophotometry, refractometry, and gravimetry. Based on the results obtained, it was shown that GBSG can be used in the processes of flotation and extraction. Acid-base equilibria in reagent solutions were studied spectrophotometrically. The obtained values of the acid dissociation constants (pKa1 = 7.93 ± 0.34; pKa2 = 10.48 ± 0.15) prove that GBSH is a weak diacid. The hydrolytic stability of the reagent was studied by the spectrophotometric method. The results of the study showed that HBHS solutions are sufficiently stable over time in alkaline media: the degree of hydrolysis within two hours is 2.35%. The surface activity of the reagent was determined by the stalagmometric method. It has been established that GBSG is a surfactant.

scholarly journals Soybean (Glycine max L.) Response to Lime and Vermicompost Amelioration of Acidic Nitisols of Assosa, North Western Ethiopia

2019 ◽  
pp. 1-18
Author(s):  
Tigist Adisu ◽  
Lemma Wogi ◽  
Tesfaye Feyisa
Keyword(s):  
Chemical Properties ◽  
Crop Productivity ◽  
Promising Alternative ◽  
Exchangeable Acidity ◽  
Combined Application ◽  
Physico Chemical ◽  
Glycine Max L ◽  
Four Levels ◽  
Cropping Seasons ◽  
Basic Cations

Acidic soils limit the production potential of crops because of low availability of basic cations and excess of hydrogen (H+) and aluminium (Al3+) in exchangeable forms. In the western part of the country such as Assosa and Wellega, soil acidity is a well-known problem limiting crop productivity. A field study was conducted to assess the effects of lime, vermicompost and their combinations on selected soil physico-chemical properties and responses of soybean grown on acidic Nitisols of Assosa area during 2016 and 2017 main cropping seasons. Soil samples were collected from the experimental site before planting and from plots after harvesting. The collected samples were analysed following the standard methods for soil physico-chemical analysis. The treatments were factorial combinations of four levels of lime (0, 1.62, 3.62 and 4.90 t ha-1) and four levels of vermicompost (0, 1.50, 3.00 and 4.50 t ha-1). The results revealed that soil pH increased from 5.31 – 5.86 pH while exchangeable acidity decreased from 5.46 - 2.85 cmol (+) kg-1 with levels of lime and vermicompost (3.26 with 3 and 4.90 with 4.5) t ha-1 respectively, which resulted in improved soil physico-chemical properties. The combined application of lime and vermicompost also significantly improved the yield related parameters of soybean. The maximum grain yield (1.95t    ha-1) was obtained from the combined application of 4.90 ton lime and 3.00 ton vermicompost ha-1 followed by combined application of 3.26 ton lime with 3.00 ton vermicompost ha-1 with non-significant variation. Therefore, the combined application of 3.26 ton lime and 3.00 ton vermicompost ha-1 is a promising alternative amendment for amelioration of acidic Nitisols of Assosa (Amba-12 Kebele) and other similar agro-ecologies for the improvement of soybean production.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

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