Enhancement of soil microstructural stability and alleviation of aluminium toxicity in acidic latosols via alkaline humic acid fertiliser amendment

2021 ◽  
pp. 120473
Author(s):  
Aini Deng ◽  
Xiaofang Wu ◽  
Chulian Su ◽  
Min Zhao ◽  
Bin Wu ◽  
...  
Keyword(s):  
Humic Acid ◽  
Aluminium Toxicity ◽  
Microstructural Stability

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

High-Temperature Instability of A Cr2Nb-Nb(Cr) Microlaminate Composite

1996 ◽  
Vol 54 ◽  
pp. 374-375
Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Aircraft Engine ◽  
Lattice Parameter ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Cross Sectional ◽  
Bcc Structure

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.

Characterization of dissolved organic matter (DOM) extracted from soils by hot water percolation (HWP)

2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Extraction Methods ◽  
Soil Samples ◽  
Hot Water ◽  
Soil Extracts ◽  
Water Percolation ◽  
Soil Humic Acid

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.

Changes in the Humic Acid–Metal Complexation Characteristics Depending on Humification Degree / Humīnskābju – Metālu Kompleksveidošanās Rakstura Izmaiņas Atkarībā No Humifikācijas Pakāpes

2012 ◽  
Vol 51 (3) ◽  
pp. 228-237
Author(s):  
D. Dudare ◽  
M. Klavins
Keyword(s):  
Humic Acid ◽  
Stability Constants ◽  
Humic Acids ◽  
Complex Stability ◽  
Peat Layer ◽  
Raised Bog ◽  
Complexing Capacity ◽  
Humification Degree ◽  
Complexation Process ◽  
Complex Stability Constants

The aim of this study is to determine the Cu(II) complexing capacity and stability constants of Cu(II) complexes of humic acids isolated from two well-characterized raised bog peat profiles in respect to the basic properties and humification characteristics of the studied peats and their humic acids. The complex stability constants significantly change within the studied bog profiles and are well correlated with the age and decomposition degree of the peat layer from which the humic acids have been isolated. Among factors that influence this complexation process, molecular mass and ability to form micellar structures (supramolecules) of humic substances are of key importance.

Major and Trace Elements in the Humic Acid

2018 ◽  
Author(s):  
Zoltán Kis ◽  
Katalin Gméling ◽  
Tímea Kocsis ◽  
János Osán ◽  
Mihály András Pocsai ◽  
...  
Keyword(s):  
Trace Elements ◽  
Humic Acid ◽  
Activation Analysis ◽  
Analytical Techniques ◽  
Major And Trace Elements ◽  
Prompt Gamma Activation Analysis ◽  
Prompt Gamma ◽  
Gamma Activation ◽  
X Ray ◽  
Precise Analysis

We present precise analysis of major and trace elements of the humic acid. We used three different element analytical techniques in our investigations as prompt-gamma activation analysis (PGAA), neutron activation analysis (NAA) and X-ray fluorescence (XRF) analysis was carried out. We identified 42 elements in our sample.

EFFECT OF IRRIGATION AND GRASSING TO CHANGE SOME OF THE BIOLOGICAL PROPERTIES OF THE MINING OF BROWN CALCAREOUS SOILS

2019 ◽  
Vol 1 (1) ◽  
pp. 29-32
Author(s):  
Ruzimurod B. Boimurodov ◽  
Zebinisso Q. Bobokhonova
Keyword(s):  
Folic Acid ◽  
Humic Acid ◽  
Humic Acids ◽  
Rapid Growth ◽  
Growth And Development ◽  
Sharp Increase ◽  
Humus Content ◽  
Calcareous Soils ◽  
Biological Properties ◽  
Humus Accumulation

In this article is showing, that the irrigation mountain brown carbonate soils prone methods of irrigation and grassing comes the rapid growth and development of natural vegetation, which leads to intensive humus accumulation. Humus content in the upper layer is increased by 0.98% and a significantly smaller severely eroded. Increasing the amount of humus promotes accumulation mainly humic acids, that conducts to expansion of relations the content of humic acid: The content of folic acid. When grassing of soil traced sharp increase in the number associated with the related and R2 O3 humic acid.

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