The significance of clays in agriculture and soils

1984 ◽  
Vol 311 (1517) ◽  
pp. 375-389 ◽  
Keyword(s):  
Soil Structure ◽  
Simple Structure ◽  
Clay Mineralogy ◽  
Future Research ◽  
Complex Structures ◽  
Size Distributions ◽  
Pore Size Distributions ◽  
The Many ◽  
Soil Behaviour ◽  
Structural Imperfections

In managing soils for agricultural production, soil texture or particle-size distribution, and the amount of clay present are very important. Soil structure depends very much on clay: soils with little clay have a simple structure, whereas soils with much clay have complex structures and multimodal pore size distributions. Their response to changes in water content is structurally quite different from that of sandy soils. Clays have a large specific surface, often predominantly negatively charged, that retains nutrients against leaching and reacts with hydrogen and aluminium ions, while buffering the soil against extreme pH changes. The clay itself may be a source of plant nutrients when it degrades. Despite these known effects it is still difficult to predict soil behaviour from clay mineralogy. This is partly because the complexities of real clays in soil have been ignored in correlative studies, and that their effects on soil bulk properties are not understood. Future research should stress both of these factors and with improvement of techniques for describing the many structural imperfections in clays, new possibilities exist for predicting those of their properties that are important in agriculture.

Structural stability, pore size distribution and surface charge properties of clay soils with varying mineralogy and organic matter content.

1969 ◽  
Vol 77 (1-2) ◽  
pp. 11-31
Author(s):  
Víctor A. Snyder ◽  
Rafael Pietri Oms ◽  
Milagros Miró ◽  
Héctor M. Lugo
Keyword(s):  
Organic Matter ◽  
Pore Size ◽  
Organic Matter Content ◽  
Clay Mineralogy ◽  
Matter Content ◽  
Clay Soils ◽  
Size Distributions ◽  
Moisture Retention ◽  
Variable Charge ◽  
Pore Size Distributions

This study evaluated interactive effects of mineralogy and organic matter content on chemical and physical properties of clay soils. Measurements were taken at different depths in four soil profiles characterized by oxidic, kaolinitic, mixed and montmorillonitic clay mineralogies, respectively. Within a given profile, organic carbon content varied more or less continuously with depth, whereas texture and mineralogy remained relatively constant. Thus in this study the combined effects of organic matter content and clay mineralogy could be evaluated in various combinations while texture remained constant. Resistance of soil aggregates to slaking by water was related primarily to soil organic matter content, with relatively minor differences attributable to mineralogy except in the oxidic soil where oxides seemed to exert an important stabilizing effect. Organic matter was associated with an increase in water-holding capacity both in the interaggregate pore space (0 to -0.33 bar moisture retention range) and intraaggregate porosity (-0.33 to -0.8 bar retention range). The enhancing effect of organic matter on intra-aggregate porosity seemed most prominent in the soils with oxidic and kaolinitic mineralogies, suggesting the importance of organic matter for maximizing plant-available water retention in these soils. For all soils and depths, pore-size distributions within the 0 to -0.33 bar moisture retention range were log-normally distributed, with the geometric mean pore diameter and log standard deviation practically constant. These results implied that although the total 0 to -0.33 bar porosity varied strongly (primarily with organic matter content), the relative pore size distributions were all similar. In agreement with other studies in the literature, effective cation exchange capacity (ECEC) increased and the zero point of charge (ZPC) of the variable charge complex decreased as organic matter increased, and as clay mineralogy varied in the order oxidic -> kaofinitic -> mixed -> montmorillonitic. Results of this study highlight the importance of managing organic matter for optimizing physical and chemical properties in soils, particularly those dominated by variable charge minerals.

CHARACTERIZATION OF PORE SIZE DISTRIBUTIONS USING NON-NEWTONIAN FLUIDS

2020 ◽  
Author(s):  
Scott C. Hauswirth ◽  
◽  
Majdi Abou Najm ◽  
Christelle Basset
Keyword(s):  
Pore Size ◽  
Newtonian Fluids ◽  
Size Distributions ◽  
Pore Size Distributions

scholarly journals Three-Dimensional Thematic Map Imaging of the Yacht Port on the Example of the Polish National Sailing Centre Marina in Gdańsk

2021 ◽  
Vol 11 (15) ◽  
pp. 7016
Author(s):  
Pawel S. Dabrowski ◽  
Cezary Specht ◽  
Mariusz Specht ◽  
Artur Makar
Keyword(s):  
Spatial Data ◽  
Convex Surface ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Future Research ◽  
Two Dimensional ◽  
Thematic Maps ◽  
Research Directions ◽  
Future Research Directions ◽  
The Many

The theory of cartographic projections is a tool which can present the convex surface of the Earth on the plane. Of the many types of maps, thematic maps perform an important function due to the wide possibilities of adapting their content to current needs. The limitation of classic maps is their two-dimensional nature. In the era of rapidly growing methods of mass acquisition of spatial data, the use of flat images is often not enough to reveal the level of complexity of certain objects. In this case, it is necessary to use visualization in three-dimensional space. The motivation to conduct the study was the use of cartographic projections methods, spatial transformations, and the possibilities offered by thematic maps to create thematic three-dimensional map imaging (T3DMI). The authors presented a practical verification of the adopted methodology to create a T3DMI visualization of the marina of the National Sailing Centre of the Gdańsk University of Physical Education and Sport (Poland). The profiled characteristics of the object were used to emphasize the key elements of its function. The results confirmed the increase in the interpretative capabilities of the T3DMI method, relative to classic two-dimensional maps. Additionally, the study suggested future research directions of the presented solution.

scholarly journals Thermoplastic Pultrusion: A Review

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 180
Author(s):  
Kirill Minchenkov ◽  
Alexander Vedernikov ◽  
Alexander Safonov ◽  
Iskander Akhatov
Keyword(s):  
Composite Structures ◽  
Raw Materials ◽  
Thermoplastic Composites ◽  
Future Research ◽  
Transportation Industry ◽  
Architectural Engineering ◽  
Simulation Techniques ◽  
New Perspective ◽  
The Many ◽  
Lower Production

Pultrusion is one of the most efficient methods of producing polymer composite structures with a constant cross-section. Pultruded profiles are widely used in bridge construction, transportation industry, energy sector, and civil and architectural engineering. However, in spite of the many advantages thermoplastic composites have over the thermoset ones, the thermoplastic pultrusion market demonstrates significantly lower production volumes as compared to those of the thermoset one. Examining the thermoplastic pultrusion processes, raw materials, mechanical properties of thermoplastic composites, process simulation techniques, patents, and applications of thermoplastic pultrusion, this overview aims to analyze the existing gap between thermoset and thermoplastic pultrusions in order to promote the development of the latter one. Therefore, observing thermoplastic pultrusion from a new perspective, we intend to identify current shortcomings and issues, and to propose future research and application directions.

Preparation of P(GMA-co-EGDMA) Monolithic Columns with Adjustable Porous Properties

2014 ◽  
Vol 936 ◽  
pp. 942-949 ◽  
Author(s):  
Hao Tian Zhang ◽  
Qiu Yu Zhang ◽  
Bao Liang Zhang ◽  
Chun Mei Li
Keyword(s):  
Pore Size ◽  
Monolithic Column ◽  
Organic Polymer ◽  
Monolithic Columns ◽  
Size Distributions ◽  
Notable Effect ◽  
Pore Size Distributions ◽  
Porous Properties ◽  
Glass Tubes ◽  
First Time

Porous properties have notable effect on separating effect of organic polymer-based monolithic column. Different applications of monolithic columns require tailored pore size distributions. On account of that, P(GMA-co-EGDMA) monolithic columns were prepared with novel ternary porogenic agents. Glass tubes was chosen as polymerization mold. Moreover, factors influencing the inner pore morphology, pore size and specific surface area were investigated systematically. The results showed that the increasing of the solubility of porogenic agents and the amount of crosslinker, the decreasing of the amount of porogenic agents and temperature rising all could give rise to the decreasing of pore size. Remarkably, the effect of initiator was studied for the first time. The results showed that amount of initiator had no remarkable influence on porous properties. By controlling effect factors, P(GMA-co-EGDMA) Monolithic Columns with pore size from dozens to thousands of nanometer, which can be applied in separation of molecules with different size.

scholarly journals Designing of Nanomaterials-Based Enzymatic Biosensors: Synthesis, Properties, and Applications

Electrochem ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 149-184
Author(s):  
Francisco T. T. Cavalcante ◽  
Italo R. R. de A. Falcão ◽  
José E. da S. Souza ◽  
Thales G. Rocha ◽  
Isamayra G. de Sousa ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
State Of The Art ◽  
Volume Ratio ◽  
The State ◽  
Future Research ◽  
Synthesis Properties ◽  
Signal Response ◽  
Enzymatic Biosensors ◽  
The Many ◽  
Biological Entities

Among the many biological entities employed in the development of biosensors, enzymes have attracted the most attention. Nanotechnology has been fostering excellent prospects in the development of enzymatic biosensors, since enzyme immobilization onto conductive nanostructures can improve characteristics that are crucial in biosensor transduction, such as surface-to-volume ratio, signal response, selectivity, sensitivity, conductivity, and biocatalytic activity, among others. These and other advantages of nanomaterial-based enzymatic biosensors are discussed in this work via the compilation of several reports on their applications in different industrial segments. To provide detailed insights into the state of the art of this technology, all the relevant concepts around the topic are discussed, including the properties of enzymes, the mechanisms involved in their immobilization, and the application of different enzyme-derived biosensors and nanomaterials. Finally, there is a discussion around the pressing challenges in this technology, which will be useful for guiding the development of future research in the area.

Coal pore size distributions controlled by the coalification process: An experimental study of coals from the Junggar, Ordos and Qinshui basins in China

Fuel ◽  
2017 ◽  
Vol 206 ◽  
pp. 352-363 ◽  
Author(s):  
Yong Li ◽  
Cheng Zhang ◽  
Dazhen Tang ◽  
Quan Gan ◽  
Xinlei Niu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Pore Size ◽  
Size Distributions ◽  
Pore Size Distributions

The many faces of suzhi in the Chinese organization and society

2014 ◽  
Vol 5 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Sean Upton-McLaughlin
Keyword(s):  
Chinese Culture ◽  
Mainland China ◽  
Future Research ◽  
Chinese Society ◽  
Content Type ◽  
Mainland Chinese ◽  
Foreign Companies ◽  
Expatriate Managers ◽  
The Many ◽  
Practical Implications

Purpose – The purpose of this paper was to explore the Chinese concept of suzhi and how it relates to behavioral standards within mainland Chinese society and the workplace. The article provides a general discussion of suzhi and its inherent elements to act as a foundation for the education of expatriate managers and executives and for future research by Chinese human resource management (HRM) scholars. Design/methodology/approach – This paper draws on the author's first-hand experience and observations from five years of living and working abroad in mainland China with Chinese companies and executives. Findings – The concept of suzhi in China is a reflection of multiple behavioral standards throughout China. And while suzhi's roots are in ancient Chinese culture and Confucianism, it is also subject to influence and change. Practical implications – The paper may serve as a foundation both for expatriate managers seeking to improve HRM practices in foreign companies in China and future scholars who wish to conduct further research on suzhi and Chinese behavioral standards as they can be applied to the workplace. Originality/value – This is an attempt to enlighten expatriate managers and executives in China on the concept of suzhi and its implication for HRM in China.

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