scholarly journals The Role of Glass Compounds in Autoclaved Bricks

Buildings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 41
Author(s):  
Anna Stepien ◽  
Beata Potrzeszcz-Sut ◽  
Dale P. Prentice ◽  
Tandre J. Oey ◽  
Magdalena Balonis
Keyword(s):  
Chemical Properties ◽  
Stable Phase ◽  
Measured Temperature ◽  
Experimental Characterization ◽  
Complex Functions ◽  
Glass Sand ◽  
The Relationship ◽  
Saturation Vapor ◽  
And Chemical Properties

This study describes the relationship between the physio-mechanical and chemical properties of sand-lime materials which have undergone hydrothermal treatment, and which were modified through the introduction of glass components (90% glass sand, GS). Process parameters such as temperature, pressure and saturation vapor pressure were found to have a significant impact on the series of chemical reactions as well as on the formation and transformation of solid hydrates. During the stirring process of sand-lime mass, the temperature of the reaction between lime and water in the presence of quartz sand (QS) was determined to be 83 °C. In the presence of glass sand, measured temperature was only 42 °C. Thermodynamic equilibrium-based modelling was applied to predict stable phase assemblages in the studied systems. It was found that compositional modification along with the application of the autoclaving process resulted in the formation of two crystalline phases: natrolite and gyrolite. Compressive strength and density were also assessed. The strength of fresh laboratory samples was found to be greater than their traditional analogues by 15 MPa. In addition to experimental characterization, sand-lime materials were also modeled using neural networks (backpropagation neural network, BPNN) which serve as a universal approximation method capable of modelling complex functions.

The Nature of S-N Bonding in Sulfonamides and Related Compounds: Insights into π-Bonding Contributions from Sulfur K-Edge XAS

2020 ◽  
Author(s):  
Tulin Okbinoglu ◽  
Pierre Kennepohl
Keyword(s):  
Density Functional ◽  
Chemical Properties ◽  
Functional Theory ◽  
Rotational Barriers ◽  
Td Dft ◽  
Nitrogen Bonds ◽  
X Ray Absorption ◽  
Related Compounds ◽  
And Chemical Properties

Molecules containing sulfur-nitrogen bonds, like sulfonamides, have long been of interest due to their many uses and chemical properties. Understanding the factors that cause sulfonamide reactivity is important, yet their continues to be controversy regarding the relevance of S-N π bonding in describing these species. In this paper, we use sulfur K-edge x-ray absorption spectroscopy (XAS) in conjunction with density functional theory (DFT) to explore the role of S<sub>3p</sub> contributions to π-bonding in sulfonamides, sulfinamides and sulfenamides. We explore the nature of electron distribution of the sulfur atom and its nearest neighbors and extend the scope to explore the effects on rotational barriers along the sulfur-nitrogen axis. The experimental XAS data together with TD-DFT calculations confirm that sulfonamides, and the other sulfinated amides in this series, have essentially no S-N π bonding involving S<sub>3p</sub> contributions and that electron repulsion and is the dominant force that affect rotational barriers.

Transportation pathways of pesticides in two major watersheds of Istanbul, Turkey

2004 ◽  
Vol 49 (3) ◽  
pp. 165-172 ◽  
Author(s):  
M. Yazgan ◽  
A. Tanik
Keyword(s):  
Chemical Properties ◽  
Surface Flow ◽  
Priority List ◽  
Pesticide Pollution ◽  
Consumption Values ◽  
Annual Consumption ◽  
Agricultural Areas ◽  
Physical And Chemical ◽  
And Chemical Properties

The study covers the investigation of pesticides in terms of consumption, toxicological classification and various intrinsic physical and chemical properties like DT50, KOC, GUS, solubility that describe the important mechanisms prevailing in soil, namely persistence and mobility. These mechanisms help to estimate the transportation pathways of pesticides on soil till they reach the receiving water after being applied on land. Classification is done in three groups, those likely to appear in surface flow, those that appear in groundwater and those that present transient conditions. Such an approach that also takes into account toxicological levels and annual consumption values of pesticides will act as a tool to prepare the priority list of pesticides that need special care during their transportation. The fate of pesticides is a difficult task to solve, however, such a methodology, puts forth a rough estimate on their behavior in spite of uncertainties in many of the parameters describing mechanisms like persistence and mobility. The agricultural areas of two watersheds of Istanbul are selected as target areas to describe the approach, which is also checked with another approach estimating pesticide pollution potential that considers various other properties of pesticides. Almost similar findings are depicted with 85% proximity. The methodology presented in the paper illustrates and emphasizes the significant role of pesticide properties in determining their fate in soil after being applied.

Exploring the role of dosing procedure and chemical properties in in vitro assays using a fish gill cell line

2009 ◽  
Vol 153 (2) ◽  
pp. S89
Author(s):  
Kristin Schirmer ◽  
Katrin Tanneberger ◽  
Nynke I. Kramer ◽  
Frans J.M. Busser ◽  
Joop L.M. Hermens ◽  
...  
Keyword(s):  
Cell Line ◽  
Chemical Properties ◽  
In Vitro Assays ◽  
Fish Gill ◽  
Gill Cell ◽  
And Chemical Properties

Chemical Bonding 1: Basic Concepts

2021 ◽  
pp. 81-101
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Chemical Bonding ◽  
Chemical Properties ◽  
Lattice Energy ◽  
Bond Polarity ◽  
Formal Charge ◽  
Basic Concepts ◽  
Lewis Structures ◽  
The Relationship ◽  
Octet Rule

Chemical Bonding I: Basic Concepts examines general ideas of chemical bonding between atoms and ions and how this bonding affects the chemical properties of the elements. An overview of Lewis symbols, Lewis structures and the octet rule is presented including the role of valence electrons in ionic and covalent bonding. The energy changes that accompany ionic bond formation are also discussed with emphasis on lattice energy. The chapter covers guidelines and general procedures for writing Lewis structures or electron dot formulas for molecular compounds and polyatomic ions. The concepts and applications of resonance, formal charge and exceptions to the octet rules are presented, along with coverage of the relationship between bond polarity and electronegativity.

scholarly journals Distribution of Available Silicon of Volcanic Ash Soils in Jeju Island

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Won-Pyo Park ◽  
Kwan-Cheol Song ◽  
Bon-Jun Koo ◽  
Hae-Nam Hyun
Keyword(s):  
Volcanic Ash ◽  
Chemical Properties ◽  
Jeju Island ◽  
A Value ◽  
Dissolved Silicon ◽  
Highly Correlated ◽  
Si Content ◽  
Pedogenic Processes ◽  
The Relationship ◽  
And Chemical Properties

In soils, dissolved silicon (Si) is adsorbed onto soil particles or is leached into groundwater through the soil profile. Andisols may play an important role in contributing to high dissolved Si concentrations in groundwater on Jeju Island, Korea. In this study, we evaluated the available Si content that potentially affects groundwater composition and investigated the relationship between the available Si content and chemical properties of volcanic ash soil on Jeju Island. We used the 1 M sodium acetate buffer (pH 4.0) to extract the available Si. Selected chemical properties were determined for 290 topsoil samples collected from different land sites throughout Jeju Island, and we analyzed the available Si content in the typifying pedons of Jeju Island and mainland Korea. The available Si content in Jeju Island topsoils ranged from 75 to 150 mg·kg−1, and the available Si content of Andisols in both orchards and grasslands was significantly higher than that of non-Andisols. The available Si content was highly correlated with the amounts of oxalate extractable Si, Al, and Fe in Andisols and was negatively related to the Alp/Alo ratio. With increasing elevation, we detected a decrease in the available Si and allophane content in Andisols, whereas Al-humus complexes increased with increasing elevation. The ratio of available Si in the lowest subsoil/topsoil increased to a value of 6.0, indicating that large amounts of available Si are present in the subsoil. The available Si content in the lowest subsoil of Andisols on Jeju Island was 10 times higher than that in the typifying pedons of the Korean mainland. In contrast, there were no differences in the available Si content between the topsoil and the subsoil of the typifying pedon series of Jeju and mainland non-Andisols because of differences in pedogenic processes. Collectively, our findings indicate that weathering of Andisols on Jeju Island potentially affects the Si concentration in groundwater.

Basic Performance Research of Polymer Intercalation Clay

2012 ◽  
Vol 578 ◽  
pp. 183-186
Author(s):  
Xiao Chun Cao ◽  
Yi Qin ◽  
Yan Na Zhao ◽  
Kun Ke
Keyword(s):  
Drilling Fluid ◽  
Chemical Properties ◽  
Drilling Fluids ◽  
Technical Problems ◽  
Clay Particles ◽  
Polymer Properties ◽  
Physical And Chemical ◽  
Performance Research ◽  
And Chemical Properties

Using the preliminary research of the polymer properties, the different between the physical and chemical properties of new polymer-clays nanometer composites and clay have been studied. Different polymers are used to evaluate experiment. Based on a large number of lab experiments, the changes of rheological property and API filtration property of polymer-clay drilling fluids nanometer composites are studied. The results show that clay particles could become smaller and the composites drilling fluid have the role of controlling loss and enhancing cake quality. The prepared composites could be used to solve the technical problems in drilling fluid.

Role of lattice defects in catalytic activities of graphene clusters for fuel cells

2015 ◽  
Vol 17 (26) ◽  
pp. 16733-16743 ◽  
Author(s):  
Lipeng Zhang ◽  
Quan Xu ◽  
Jianbing Niu ◽  
Zhenhai Xia
Keyword(s):  
Fuel Cells ◽  
Electronic Structures ◽  
Chemical Properties ◽  
Lattice Defects ◽  
Physical And Chemical Properties ◽  
Catalytic Activities ◽  
Physical And Chemical ◽  
And Chemical Properties

Defects are common but important in graphene, which could significantly tailor the electronic structures and physical and chemical properties.

scholarly journals Changes in Colour, Strength and Chemical Properties of Oil Heat Treated 18-Years Old Planted Acacia mangium

2017 ◽  
Vol 9 (3) ◽  
pp. 12
Author(s):  
Razak Wahab ◽  
Ros Syazmini M. Ghani ◽  
Hashim W. Samsi ◽  
Mohd Sukhairi M. Rasat
Keyword(s):  
Heat Treatment ◽  
Chemical Properties ◽  
Treated Wood ◽  
Acacia Mangium ◽  
Chemical Compositions ◽  
Bending Tests ◽  
Colour Strength ◽  
Heat Treated ◽  
The Relationship ◽  
And Chemical Properties

This study was carried to investigate changes in the oil heat treated 18-years old of planted Acacia mangium. Harvested trees segregated into bottom, middle and top portions containing heartwood and sapwood were oil heat treated in stainless tank with palm crude oil as heating medium at temperatures of 180oC, 200oC and 220oC for 30, 60 and 90 minutes respectively. The evaluation of the changes in the wood were performed by standards using a Minolta Chroma Meter, TAPPI Standard T204 om-88, TAPPI Standard T203 cm-99, TAPPI Standard T222 cm-02, and BS EN 310:1993 static bending tests. The relationship between the changes in the colour, mechanical and chemical composition, were made using correlation analysis. The result showed oil-heat treatment reduced the lightness of the wood and darkened the both parts of the wood. The strength of the wood reduced slightly after the oil-heat treatment. In the chemical compositions, the percentages of the holocellulose, α-cellulose, hemicellulose and extractive contents decrease with the increase in treatment duration and temperature. The oil heat treatment process at 200°C for duration 60 minutes is recommended for acacia mangium wood as it improved the colour of Acacia mangium and standardized the colour of sapwood and heartwood. The loss in strength at this temperature and duration is acceptable as the treated wood only loss up to 15% strength in MOR and 10.7% in MOE.

scholarly journals Zeolites application in terrestrial and space industry – a review

2020 ◽  
Vol 32 ◽  
pp. 209-223
Author(s):  
Adelina Miteva ◽  
Valeria Stoyanova
Keyword(s):  
Chemical Properties ◽  
Waste Materials ◽  
Ion Exchangers ◽  
Science And Engineering ◽  
Space Industry ◽  
Synthetic Zeolites ◽  
The Impact ◽  
And Chemical Properties

This brief overview presents an attempt to systematize some of the available historical and recent data on the impact of zeolite science and engineering on the progress of various areas of Earth and Space development. The basic structural and chemical properties of natural and synthetic zeolites are presented. Valuable applications of the zeolites, such as catalysts, gas adsorbers and ion exchangers are also included. The most commonly used methods for the synthesis of zeolites from different materials are presented, as well as some Bulgarian developments for the reuse of waste materials to zeolites. The important role of zeolites as an indispensable material for improving the quality of soil, fuels, water, air, etc., required for the needs of orbiting space stations and spacecrafts has been confirmed by typical examples.

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