Effects of Temperature and Dry Density on Hydraulic Conductivity of Silty Clay under Infiltration of Low-Temperature Water

2013 ◽  
Vol 39 (1) ◽  
pp. 461-466 ◽  
Author(s):  
Jie Ren ◽  
Zhen-zhong Shen ◽  
Jie Yang ◽  
Jian Zhao ◽  
Ji-na Yin
Keyword(s):  
Hydraulic Conductivity ◽  
Low Temperature ◽  
Dry Density ◽  
Silty Clay ◽  
Effects Of Temperature ◽  
Temperature Water

scholarly journals Geotechnical Characteristics of Regolith Derived from Nanka Formation, Southeast Nigeria

2020 ◽  
Vol 5 (12) ◽  
pp. 67-75
Author(s):  
Stella Nwaife Chibuzor ◽  
Elizabeth lfeyinwa Okoyeh ◽  
Boniface Chukwukadibia Ezeanyaoha Egboka
Keyword(s):  
Hydraulic Conductivity ◽  
Field Experiments ◽  
Liquid Limit ◽  
Dry Density ◽  
Silty Clay ◽  
Soil Infiltration ◽  
Maximum Dry Density ◽  
Angle Of Internal Friction ◽  
Average Value ◽  
Geotechnical Characteristics

Regolith derived from Nanka Formation; Southeast Nigeria was evaluated for their geotechnical characteristics. The methods of investigations include Fieldwork experiment and laboratory analysis of water and soil samples. The result of hydraulic parameters of the soil at 1meter, 2 meters depth and drilled cuttings from boreholes revealed permeability average values of 1.29E-05(cm/s) and 9.15E-6(cm/s), hydraulic conductivity average value of 1.27E-04(cm/s) and 8.93E-05(cm/s). Drilled cuttings from three boreholes revealed permeability average value of 8.15E-06(m/s), 2.68E-06(m/s) and 6.20E-06, hydraulic conductivity average values of 8.90E-03(m/s), 2.92E-03(m/s) and 6.75E-3(m/s).These values indicate permeable soil with high hydraulic conductivity typical of silty-clay and sand. The permeability/hydraulic conductivity accounts for the high infiltration/percolation of water into the soil. Infiltration of water through the soil initiates geochemical reactions and dissolution mineral which leaves the soil loose and unconsolidated. Geotechnical characteristics show low to medium plasticity and a liquid limit average of 42.36 and 35.45, indicating the capacity of the soil to absorb moisture and expand, bulk density average value of 1.90 mg/m3and compaction test of maximum dry density average value of 1.80 g/cm3 at an optimum water content average of 12.89% indicate low density. Shear strength components of cohesion values range from 0 to 55KN/m2 with average value of 25 KN/m2 and friction angle values range from 7° to 25° suggesting low cohesion and angle of internal friction. This is attributed to the low clay content and the cohesive force is not enough to sustain the soil. Field experiments of cone penetration test of in-situ results indicate a weak and incompetent soil material that is unstable and vulnerable to erosion. The finding would be relevant in soil mechanics problems.

scholarly journals Effects of temperature, dry density and water content on the thermal conductivity of Genhe silty clay

2020 ◽  
Vol 16 ◽  
pp. 102830 ◽  
Author(s):  
Xiangtian Xu ◽  
Weidong Zhang ◽  
Caixia Fan ◽  
Gaosheng Li
Keyword(s):  
Thermal Conductivity ◽  
Water Content ◽  
Dry Density ◽  
Silty Clay ◽  
Effects Of Temperature

Assessment of the Role of Different Soil Properties on Crust Strength by Linear Regression Models

2019 ◽  
Vol 6 (04) ◽  
Author(s):  
MINAKSHI SERAWAT ◽  
V K PHOGAT ◽  
ANIL Abdul KAPOOR ◽  
VIJAY KANT SINGH ◽  
ASHA SERAWAT
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Crop Yields ◽  
Modulus Of Rupture ◽  
Silty Clay ◽  
Linear Regression Models ◽  
Wide Range ◽  
Dispersion Ratio ◽  
Crust Strength

Soil crust strength influences seedling emergence, penetration and morphology of plant roots, and, consequently, crop yields. A study was carried out to assess the role of different soil properties on crust strength atHisar, Haryana, India. The soil samples from 0-5 and 5-15 cm depths were collected from 21 locations from farmer’s fields, having a wide range of texture.Soil propertieswere evaluated in the laboratory and theirinfluence on the modulus of rupture (MOR), which is the measure of crust strength, was evaluated.The MOR of texturally different soils was significantly correlated with saturated hydraulic conductivity at both the depths. Dispersion ratio was found to decrease with an increase in fineness of the texture of soil and the lowest value was recorded in silty clay loam soil,which decreased with depth. The modulus of rupture was significantly negatively correlative with the dispersion ratio.There was no role of calcium carbonate in influencing the values of MOR of soils. Similarly,the influence of pH, EC and SAR of soil solution on MOR was non-significant.A perusal of thevalues of the correlations between MOR and different soil properties showed that the MOR of soils of Haryana are positively correlated with silt + clay (r = 0.805) followed by water-stable aggregates (r = 0.774), organic carbon (r = 0.738), silt (r = 0.711), mean weight diameter (r = 0.608) and clay (r = 0.593) while negatively correlated with dispersion ratio (r = - 0.872), sand (r = -0.801) and hydraulic conductivity (r = -0.752) of soils.

scholarly journals Low Temperature Water-Gas Shift: Enhancing Stability through Optimizing Rb Loading on Pt/ZrO2

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 210
Author(s):  
Caleb Daniel Watson ◽  
Michela Martinelli ◽  
Donald Charles Cronauer ◽  
A. Jeremy Kropf ◽  
Gary Jacobs
Keyword(s):  
Low Temperature ◽  
Hydrogen Transfer ◽  
Water Gas Shift ◽  
Significant Shift ◽  
Catalyst Activation ◽  
X Ray ◽  
Temperature Programmed ◽  
Water Gas ◽  
X Ray Absorption ◽  
Temperature Water

Recent studies have shown that appropriate levels of alkali promotion can significantly improve the rate of low-temperature water gas shift (LT-WGS) on a range of catalysts. At sufficient loadings, the alkali metal can weaken the formate C–H bond and promote formate dehydrogenation, which is the proposed rate determining step in the formate associative mechanism. In a continuation of these studies, the effect of Rb promotion on Pt/ZrO2 is examined herein. Pt/ZrO2 catalysts were prepared with several different Rb loadings and characterized using temperature programmed reduction mass spectrometry (TPR-MS), temperature programmed desorption (TPD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), an X-ray absorption near edge spectroscopy (XANES) difference procedure, extended X-ray absorption fine structure spectroscopy (EXAFS) fitting, TPR-EXAFS/XANES, and reactor testing. At loadings of 2.79% Rb or higher, a significant shift was seen in the formate ν(CH) band. The results showed that a Rb loading of 4.65%, significantly improves the rate of formate decomposition in the presence of steam via weakening the formate C–H bond. However, excessive rubidium loading led to the increase in stability of a second intermediate, carbonate and inhibited hydrogen transfer reactions on Pt through surface blocking and accelerated agglomeration during catalyst activation. Optimal catalytic performance was achieved with loadings in the range of 0.55–0.93% Rb, where the catalyst maintained high activity and exhibited higher stability in comparison with the unpromoted catalyst.

Popcorn-like aluminum-based powders for instant low-temperature water vapor hydrogen generation

2020 ◽  
pp. 100602
Author(s):  
Xinren Chen ◽  
Cuiping Wang ◽  
Yuheng Liu ◽  
Yansong Shen ◽  
Qijun Zheng ◽  
...  
Keyword(s):  
Water Vapor ◽  
Low Temperature ◽  
Hydrogen Generation ◽  
Temperature Water

scholarly journals Analysis of Mechanical Properties and Mechanism of Natural Rubber Waterstop after Aging in Low-Temperature Environment

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2119
Author(s):  
Lin Yu ◽  
Shiman Liu ◽  
Weiwei Yang ◽  
Mengying Liu
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Energy Dispersive Spectrometry ◽  
Permanent Deformation ◽  
Test Chamber ◽  
Accelerate Aging ◽  
Aging Mechanism ◽  
Temperature Environment ◽  
Freezing Test ◽  
Temperature Water

In order to elucidate the aging performance and aging mechanism of a rubber waterstop in low-temperature environments, the rubber waterstops were placed in the freezing test chamber to accelerate aging, and then we tested its tensile strength, elongation, tear strength, compression permanent deformation and hardness at different times. Additionally, the damaged specimens were tested by scanning electron microscope, Fourier transform infrared spectroscopy and energy dispersive spectrometry. The results showed that with the growth of aging time, the mechanical properties of the rubber waterstop are reduced. At the same time, many protrusions appeared on the surface of the rubber waterstop, the C element gradually decreased, and the O element gradually increased. During the period of 72–90 days, the content of the C element in the low-temperature air environment significantly decreased compared with that in low-temperature water, while the content of O element increased significantly.

scholarly journals Characterization of Gas Transport Properties of Compacted Solid Waste Materials

Environments ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 26
Author(s):  
Muhammad Rashid Iqbal ◽  
Hiniduma Liyanage Damith Nandika ◽  
Yugo Isobe ◽  
Ken Kawamoto
Keyword(s):  
Hydraulic Conductivity ◽  
Solid Waste ◽  
Gas Transport ◽  
Bottom Ash ◽  
Gas Diffusion ◽  
Saturated Hydraulic Conductivity ◽  
Dry Density ◽  
Transport Parameters ◽  
Functional Relations ◽  
Mixed Waste

Gas transport parameters such as gas diffusivity (Dp/D0), air permeability (ka), and their dependency on void space (air-filled porosity, ε) in a waste body govern convective air and gas diffusion at solid waste dumpsites and surface emission of various gases generated by microbial processes under aerobic and anaerobic decompositions. In this study, Dp/D0(ε) and ka(ε) were measured on dumping solid waste in Japan such as incinerated bottom ash and unburnable mixed waste as well as a buried waste sample (dumped for 20 years). Sieved samples with variable adjusted moistures were compacted by a standard proctor method and used for a series of laboratory tests for measuring compressibility, saturated hydraulic conductivity, and gas transport parameters. Results showed that incinerated bottom ash and unburnable mixed waste did not give the maximum dry density and optimum moisture content. Measured compressibility and saturated hydraulic conductivity of tested samples varied widely depending on the types of materials. Based on the previously proposed Dp/D0(ε) models, the diffusion-based tortuosity (T) was analyzed and unique power functional relations were found in T(ε) and could contribute to evaluating the gas diffusion process in the waste body compacted at different moisture conditions.

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