Soil mineralogy and slope effects on infiltration, interrill erosion, and slope factor

2004 ◽  
Vol 40 (3) ◽  
Author(s):  
M. Ben-Hur ◽  
I. I. C. Wakindiki
Keyword(s):  
Soil Mineralogy ◽  
Slope Factor ◽  
Interrill Erosion

Compressive response of some agricultural soils influenced by the mineralogy and moisture

2013 ◽  
Vol 27 (3) ◽  
pp. 239-246 ◽  
Author(s):  
A.E. Ajayi ◽  
M.S. Dias Junior ◽  
N. Curi ◽  
I. Oladipo
Keyword(s):  
Agricultural Soils ◽  
Tropical Soils ◽  
Homogeneity Test ◽  
Confined Compression ◽  
Moisture Retention ◽  
Soil Mineralogy ◽  
Undisturbed Soil ◽  
Statistical Homogeneity ◽  
Compressive Response ◽  
Fine Clay

Abstract This study aimed to investigate the mineralogy, moisture retention, and the compressive response of two agricultural soils from South West Nigeria. Undisturbed soil cores at the A and B horizons were collected and used in chemical and hydrophysical characterization and confined compression test. X-ray diffractograms of oriented fine clay fractions were also obtained. Our results indicate the prevalence of kaolinite minerals relating to the weathering process in these tropical soils. Moisture retention by the core samples was typically low with pre-compression stress values ranging from50 to 300 kPa at both sites. Analyses of the shape of the compression curves highlight the influence of soil moisture in shifts from the bi-linear to S-shaped models. Statistical homogeneity test of the load bearing capacity parameters showed that the soil mineralogy influences the response to loading by these soils. These observations provide a physical basis for the previous classification series of the soils in the studied area. We showed that the internal strength attributes of the soil could be inferred from the mineralogical properties and stress history. This could assist in decisions on sustainable mechanization in a datapoor environment.

Interaction between Raindrops Splash and Sheet Flow in Interrill Erosion of Steep Hillslopes

2015 ◽  
Vol 48 (7) ◽  
pp. 595-604
Author(s):  
Myeong Jun Nam ◽  
◽  
Sang Deog Park ◽  
Seung Kyu Lee ◽  
Seung Sook Shin
Keyword(s):  
Sheet Flow ◽  
Interrill Erosion

scholarly journals Comparison of Recreational Fish Consumption Advisories Across the USA

2021 ◽  
Author(s):  
Brittany M. Cleary ◽  
Megan E. Romano ◽  
Celia Y. Chen ◽  
Wendy Heiger-Bernays ◽  
Kathryn A. Crawford
Keyword(s):  
Mississippi River ◽  
Fish Consumption ◽  
Lake Michigan ◽  
Acute Tolerance ◽  
Health Goals ◽  
Fish Consumption Advisories ◽  
Regional Collaboration ◽  
Slope Factor ◽  
The Usa ◽  
Lower Mississippi River

Abstract Purpose of Review Our comparative analysis sought to understand the factors which drive differences in fish consumption advisories across the USA — including exposure scenarios (acute and chronic health risk, non-cancer and cancer health endpoints), toxicity values (reference dose, cancer slope factor, acute tolerance level), and meal size and bodyweight assumptions. Recent Findings Fish consumption provides essential nutrients but also results in exposure to contaminants such as PCBs and methylmercury. To protect consumers from the risks of fish contaminants, fish consumption advisories are established, most often by state jurisdictions, to estimate the amount of a certain fish species a person could consume throughout their lifetime without harm. However, inconsistencies in advisories across the USA confuse consumers and undermine the public health goals of fish advisory programs. To date, no rigorous comparison of state and national fish consumption advisories has been reported. Summary Our work identifies discrepancies in key assumptions used to derive risk-based advisories between US states, reflecting differences in the interpretation of toxicity science. We also address the implications for these differences by reviewing advisories issued by contiguous states bordering two waterbodies: Lake Michigan and the Lower Mississippi River. Our findings highlight the importance of regional collaboration when issuing advisories, so that consumers of self-caught fish are equipped with clear knowledge to make decisions to protect their health.

Development of a dermal cancer slope factor for benzo[a]pyrene

2006 ◽  
Vol 45 (2) ◽  
pp. 159-168 ◽  
Author(s):  
A. Knafla ◽  
K.A. Phillipps ◽  
R.W. Brecher ◽  
S. Petrovic ◽  
M. Richardson
Keyword(s):  
Slope Factor

scholarly journals Livestock Grazing Impacts on Interrill Erosion in Pakistan

1995 ◽  
Vol 48 (3) ◽  
pp. 251 ◽  
Author(s):  
F. Bari ◽  
M. K. Wood ◽  
L. Murray
Keyword(s):  
Livestock Grazing ◽  
Grazing Impacts ◽  
Interrill Erosion

scholarly journals Physics and Modeling of Various Hazardous Landslides

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 108
Author(s):  
Jόnas Elíasson ◽  
Þorsteinn Sæmundsson
Keyword(s):  
Turbulent Flows ◽  
High Velocity ◽  
Wave Theory ◽  
Type I ◽  
Flow Paths ◽  
Stable Slope ◽  
Slope Factor ◽  
New Type ◽  
Flowing Material ◽  
Type Studies

In 2014, the Varnes classification system for landslides was updated. Complex landslides can still be a problem to classify as the classification does not include the flow type in the hydrodynamical sense. Three examples of Icelandic landslides are presented and later used as case studies in order to demonstrate the methods suggested to analyze the flow. The methods are based on the different physical properties of the flow types of the slides. Three different flow types are presented, named type (i), (ii), and (iii). Types (i) and (ii) do not include turbulent flows and their flow paths are sometimes independent of the velocity. Type (iii) include high velocity flows; they are treated with the translator wave theory, where a new type of a slope factor is used. It allows the slide to stop when the slope has flattened out to the value that corresponds to the stable slope property of the flowing material. The type studies are for a fast slide of this type, also a large slip circle slide that turns into a fast-flowing slide farther down the path and finally a large slide running so fast that it can run for a kilometer on flat land where it stops with a steep front.

Differential Expression of Three Distinct Potassium Currents in the Ventral Cochlear Nucleus

2003 ◽  
Vol 89 (6) ◽  
pp. 3070-3082 ◽  
Author(s):  
Jason S. Rothman ◽  
Paul B. Manis
Keyword(s):  
Differential Expression ◽  
Cochlear Nucleus ◽  
Nerve Fibers ◽  
Delayed Rectifier ◽  
High Threshold ◽  
Type I ◽  
Acoustic Environment ◽  
Ventral Cochlear Nucleus ◽  
Wide Range ◽  
Slope Factor

In the ventral cochlear nucleus (VCN), neurons transform information from auditory nerve fibers into a set of parallel ascending pathways, each emphasizing different aspects of the acoustic environment. Previous studies have shown that VCN neurons differ in their intrinsic electrical properties, including the K+ currents they express. In this study, we examine these K+ currents in more detail using whole cell voltage-clamp techniques on isolated VCN cells from adult guinea pigs at 22°C. Our results show a differential expression of three distinct K+ currents. Whereas some VCN cells express only a high-threshold delayed-rectifier-like current ( IHT), others express IHT in combination with a fast inactivating current ( IA) and/or a slow-inactivating low-threshold current ( ILT). IHT, ILT, and IA, were partially blocked by 1 mM 4-aminopyridine. In contrast, only ILT was blocked by 10–100 nM dendrotoxin-I. A surprising finding was the wide range of levels of ILT, suggesting ILT is expressed as a continuum across cell types rather than modally in a particular cell type. IA, on the other hand, appears to be expressed only in cells that show little or no ILT, the Type I cells. Boltzmann analysis shows IHT activates with 164 ± 12 (SE) nS peak conductance, -14.3 ± 0.7 mV half-activation, and 7.0 ± 0.5 mV slope factor. Similar analysis shows ILT activates with 171 ± 22 nS peak conductance, -47.4 ± 1.0 mV half-activation, and 5.8 ± 0.3 mV slope factor.

Systematic approach to assessing the applicability of fly-ash-based geopolymer for clay stabilization

2020 ◽  
Vol 57 (9) ◽  
pp. 1356-1368 ◽  
Author(s):  
Hayder H. Abdullah ◽  
Mohamed A. Shahin ◽  
Megan L. Walske ◽  
Ali Karrech
Keyword(s):  
Fly Ash ◽  
Systematic Approach ◽  
Soil Stabilization ◽  
Ground Improvement ◽  
Experimental Program ◽  
Attractive Alternative ◽  
Chemical Additives ◽  
Soil Mineralogy ◽  
Problematic Soils ◽  
Ph Level

Traditional soil stabilization by chemical additives such as cement and lime is a well-established technique for ground improvement of problematic soils. However, with the advantage of lower carbon emission and energy consumption, fly-ash-based geopolymer has recently become an attractive alternative to traditional stabilizers. Nevertheless, the literature lacks systemic approaches that assist engineers to apply this promising binder for soil stabilization, including the proper dosages required for an effective treatment. This paper introduces a systematic approach to assess the applicability of fly-ash-based geopolymer for stabilization of clay soils, through a comprehensive experimental program where engineered and natural clays were examined and evaluated, including soil compaction, plasticity, compressive strength, durability, pH level, and impact of pulverization. The results revealed several factors that influence the level of enhancement of geopolymer-treated clays, including the soil mineralogy, plasticity–activity properties, geopolymer concentration, curing time, and pulverization.

scholarly journals ARAHAN PENGGUNAAN LAHAN DAN PERENCANAAN KONSERVASI TANAH DAN AIR DI DAS YEH EMPAS, TABANAN, BALI

2015 ◽  
Vol 9 (1) ◽  
pp. 54
Author(s):  
I Gusti Agung Lanang Widyantara ◽  
I Nyoman Merit ◽  
I Wayan Sandi Adnyana
Keyword(s):  
Land Use ◽  
Land Use Planning ◽  
Land Use Changes ◽  
Daily Rainfall ◽  
Research Area ◽  
High Density ◽  
Scoring Method ◽  
Management Actions ◽  
Erosion Prediction ◽  
Slope Factor

Damage to forest resources has caused the environmental balance of watersheds (DAS) becomes damaged. It often causes the result of high levels of erosion. One of the land use changes that are currently happening is in Yeh Empas watershed. With this research can be known the proposed land use and appropriate land use planning on Yeh Empas watershed. Erosion prediction using the USLE (Universal Soil Loss Equation) method is to estimate how much the rate of erosion is happening and also to get an idea how good land management actions for the region. The proposed land use determination is using the scoring method by combining the slope factor of the field, the soil sensitivity of erosion, and the intensity of daily rainfall. Soil sampling was done by taking soil samples from a total of 11 samples of soil from the land unit. This research conducted to estimate the rate of erosion, to determines how much erosion can be tolerated in Yeh Empas watershed, and its relationship with the factors that influence it, as well as to determine the proposed of land use. The results of erosion prediction on each unit of land in the research area ranged from 1.75 to 1,254.96 tons/ha/year and has a grade level of erosion from slight to very severe. The result of tolerated erosion ranged from 15.06 to 24.32 tons/ha/year. The value of erosion prediction that exceeded from tolerated erosion value occurs on land units 7, 8, and 9. On that land units required proposed of land use and soil conservation techniques so that the value of erosion prediction could be below from tolerated erosion value. The analysis results of the proposed land use in Yeh Empas watershed, for areas inside the forest is proposed to protected forest (land units 1, 2, 3, 4, 5, and 6) and the management is by planting plants that are adapted to the contour lines of slope. In the areas outside the forest is proposed for annual crop cultivation area (land units 7, 8, and 9)the management with the farming plantation development, high density growing crops and terracing and also for crops cultivation area (land units 10 and 11) management by mulching, cover soil with high density and terracing.

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