scholarly journals Experimental Investigation into Compressive Behaviour and Preconsolidation Pressure of Structured Loess at Different Moisture Contents

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yali Xu ◽  
Panpan Guo ◽  
Chengwei Zhu ◽  
Gang Lei ◽  
Kang Cheng
Keyword(s):  
Moisture Content ◽  
Yield Stress ◽  
Structural Strength ◽  
Loess Soil ◽  
Undisturbed Soil ◽  
Moisture Contents ◽  
Compressive Behaviour ◽  
Preconsolidation Pressure ◽  
Before And After ◽  
Oedometer Tests

This paper investigates the influence of the structured property of loess on its compressive behaviour and proposes a new method for determining the preconsolidation pressure of structured loess soil. A series of oedometer tests were carried out on undisturbed and remoulded loess samples prepared at various moisture contents. The effects of moisture content on the structured yield stress, the preconsolidation pressure, and the structural strength were also captured. It was found that the influence of the structured property of loess on the compression behaviour is divergent between undisturbed and remoulded loess samples. The discrepancy before and after structural yielding is more remarkable for the undisturbed soil. The Casagrande method realized through the MATLAB program can effectively eliminate human factors and accurately calculate the corresponding preconsolidation pressure for undisturbed soil. The effects of moisture content on the method for determining the preconsolidation pressure considering the structured property of loess were discussed. The determination method can accurately evaluate the loess consolidation state in loess regions. The influencing rules which the moisture content exerts on the structured yield stress, the preconsolidation pressure, and the structural strength all conform to exponential functions. The study is of great significance to correctly differentiating the foundation consolidation states and calculating the ground settlement in loess regions.

Effect of Millet Stalks and Shea Nut Shells on Biogas Production

2021 ◽  
Vol 47 (2) ◽  
pp. 292-296
Author(s):  
Cosmos Moki Elinge ◽  
Ayodeji Rapheal Ige ◽  
Morenike O. Adesina ◽  
Harrison Ogala ◽  
Lawal Gusau Hassan ◽  
...  
Keyword(s):  
Moisture Content ◽  
Organic Compounds ◽  
Anaerobic Condition ◽  
Biogas Production ◽  
Biogas Yield ◽  
Moisture Contents ◽  
Average Production ◽  
Good Material ◽  
Before And After

Biogas production undergoes decomposition of organic compounds under anaerobic condition. This present work investigated the yield of biogas production from Shea nut shell and millet stalk and their blends with sheep dung. It was revealed that sheep dung (control) had the highest yield with an average production of 187.8 ml of gas for 102 days followed by sheanut shell - sheep dung blends which had 123.3 ml of gas for 102 days. Millet stalk - sheep dung blends recorded 75.9 ml of gas for 79 days. Shea nut shell and millet stalk presented 31.5 ml of gas for 81 days and 7.1 ml of gas for 48 days respectively while the pH for production ranged from 10.1 to 4.6. The moisture contents recorded for millet stalk, Shea nut shell and sheep dung before and after production were 40%, 45%, 65% and 80%, 65%, 85 respectively, and also the recorded ash contents before and after production were, 35%, 45%, 40% and 85%, 75%, 65%, respectively. It was observed that the blending of Shea nut shell and sheep dung greatly improves biogas yield while Millet stalks alone are good material for biogas production at a reasonable pH and moisture content values.

scholarly journals Soil compaction due to forest harvest operations

2007 ◽  
Vol 42 (2) ◽  
pp. 257-264 ◽  
Author(s):  
Moacir de Souza Dias Junior ◽  
Sebastião da Fonseca ◽  
Cezar Francisco Araújo Júnior ◽  
Arystides Resende Silva
Keyword(s):  
Soil Compaction ◽  
Soil Samples ◽  
Compression Tests ◽  
Forest Harvest ◽  
Undisturbed Soil ◽  
Soil Class ◽  
Eucalyptus Plantation ◽  
Capacity Model ◽  
Preconsolidation Pressure ◽  
Before And After

The objective of this work was to determine, through the use of the bearing capacity model, the traffic effects of the forest harvest operations on the preconsolidation pressure (sigmap), during one cycle of the eucalyptus plantation. The work was conducted using undisturbed soil samples, collected at the surface of the A horizon and in the top of the B horizon of an Udult (PA), Aquox (FX) and Udox (LA) soils. The undisturbed soil samples were used in the uniaxial compression tests. The soil sampling was done before and after the harvest operations. The operations performed with the Forwarder caused greater soil compaction than the ones done with the Feller Büncher and Harvester. The percentage of soil samples, in the region with additional soil compaction, indicated that the Udult was the soil class more susceptible to soil compaction, followed by the Aquox and Udox. Despite Udult is the more susceptible to soil compaction, the regeneration of the soil structure in this soil class was more efficient than in Aquox. The percentage of soil samples with sigmap values in the region with additional soil compaction in 1996, 1998 and 2004, after harvest operations, indicated a sustainable forest exploration in this period.

scholarly journals Traffic effects on the soil preconsolidation pressure due to eucalyptus harvest operations

2005 ◽  
Vol 62 (3) ◽  
pp. 248-255 ◽  
Author(s):  
Moacir de Souza Dias Junior ◽  
Fernando Palha Leite ◽  
Edson Lasmar Júnior ◽  
Cezar Francisco Araújo Junior
Keyword(s):  
Soil Compaction ◽  
Soil Structure ◽  
Soil Samples ◽  
Compression Tests ◽  
Undisturbed Soil ◽  
Structure Degradation ◽  
Preconsolidation Pressure ◽  
Before And After ◽  
Two Stages ◽  
Wood Transport

One of the limitations for reaching sustainable forest development is related to the traffic of machines and vehicles during harvest operations and wood transport, which may cause soil structure degradation. Seeking a way to analyze this problem, the objective of this study was to determine the traffic effects due to harvest operations and wood transport, on the preconsolidation pressure (sigmap) in a Typic Acrustox cultivated with eucalyptus. This study was conducted using undisturbed soil samples collected at the 0.1-0.125 m depth. Undisturbed soil samples were used in the uniaxial compression tests. Soil sampling consisted of two stages, before and after the mechanized harvest operations. The traffic effects on the sigmap in the dry season indicated that the soil compaction process was neither evident nor important. However, in the rainy season the traffic effects on the sigmap indicated that the operations performed with Harvester and Forwarder caused greater soil compaction than those with Motorized Saw and Manual, which caused less soil compaction.

The Smoulder Stream of Cigarettes / Zur Kenntnis des Glimmstromes von Cigaretten

1965 ◽  
Vol 3 (2) ◽  
Author(s):  
F. Seehofer ◽  
W. Schulz
Keyword(s):  
Moisture Content ◽  
Spatial Position ◽  
High Yield ◽  
Physical Conditions ◽  
Moisture Contents ◽  
Cigarette Paper ◽  
First Time

AbstractThe phenomenon of the smoulder stream flowing through the cigarette during smouldering and during the puff intervals is demonstrated for the first time and its dependence upon physical conditions is examined. The volume of the smoulder stream can amount up to 180 ml per cigarette. Increasing draw resistance of the cigarette and augmenting moisture content of the tobacco as well as perforation of the cigarette paper have a decreasing effect on volume and velocity of the smoulder stream. The porosity of the cigarette paper has no perceptible influence. The spatial position of the cigarette affects volume and velocity of the smoulder stream. The influence exercised by the smoulder stream on the yields of total condensate, nicotine, phenols, aldehydes, and acroleine when the cigarette tip is open during the puff intervals is determined. When the moisture contents of the tobacco were extremely high, yield decreases reaching 50 % could be observed.

scholarly journals Effect of wood biomass components on self-heating

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Nozomi Miyawaki ◽  
Takashi Fukushima ◽  
Takafumi Mizuno ◽  
Miyao Inoue ◽  
Kenji Takisawa
Keyword(s):  
Moisture Content ◽  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Chemical Oxidation ◽  
Spontaneous Ignition ◽  
Emission Spectrometry ◽  
Inductively Coupled ◽  
Self Heating ◽  
Inorganic Substances ◽  
Before And After

AbstractBiomass may ignite due to biological oxidation and chemical oxidation. If this phenomenon (spontaneous ignition) is controlled, it would be possible to produce biochar at a lower cost without the need for an external heat resource. We investigated if self-heating could be controlled by using sawdust and bark chips. When sawdust and bark chips were used under controlled conditions, the bark chips temperature increased to the torrefaction temperature. The ash content of bark chips was ~ 2%d.b. higher than that of sawdust; consequently, the inorganic substances contained in the bark chips might affect the self-heating. Self-heating was suppressed when inorganic substances were removed by washing with water. Therefore, the inorganic substances in the biomass might have affected self-heating. The inorganic element contents of the bark chips were measured by inductively coupled plasma optical emission spectrometry before and after washing. The potassium content of the bark chips was reduced remarkably by washing, and there was a possible influence of potassium on self-heating. Finally, the effect of moisture content on self-heating was investigated to obtain stable reactivity. Thus, at a moisture content of 40%w.b., a steady self-heating behavior may be realized.

Developing a Linearization Method to Determine Optimum Blending for Surimi with Varied Moisture Contents Using Linear Programming

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Hyeon W. Park ◽  
Jae W. Park ◽  
Won B. Yoon
Keyword(s):  
Linear Programming ◽  
Moisture Content ◽  
Standard Procedure ◽  
Unit Cost ◽  
Linearization Method ◽  
Model Parameters ◽  
Additional Information ◽  
Moisture Contents ◽  
Design Variables ◽  
Critical Moisture

AbstractNovel algorithm to determine the least cost formulation of a surimi blend was developed using linear programming (LP). Texture properties and the unit cost of surimi blend at the target moisture content were used as constraint functions and the objective function, respectively. The mathematical models to describe the moisture content dependence of the ring tensile properties were developed using critical moisture content, and the model parameters were used for the least cost LP (LCLP) model. The LCLP model successfully predicted the quality of surimi blend. Sensitivity analysis was used to obtain an additional information when the perturbations of design variables are provided. A standard procedure to determine the least cost formulation for blending surimi with varied moisture contents was systematically developed.

scholarly journals Experimental Study on the Softening Characteristics of Sandstone and Mudstone in Relation to Moisture Content

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Gui-chen Li ◽  
Chong-chong Qi ◽  
Yuan-tian Sun ◽  
Xiao-lin Tang ◽  
Bao-quan Hou
Keyword(s):  
Moisture Content ◽  
Vertical Displacement ◽  
Surface Porosity ◽  
Shear Tests ◽  
Moisture Contents ◽  
Dynamic Finite Element ◽  
Rock Types ◽  
Underground Roadway ◽  
The Stability ◽  
Kinetics Of

The kinetics of fluid-solid coupling during immersion is an important topic of investigation in rock engineering. Two rock types, sandstone and mudstone, are selected in this work to study the correlation between the softening characteristics of the rocks and moisture content. This is achieved through detailed studies using scanning electron microscopy, shear tests, and evaluation of rock index properties during exposure to different moisture contents. An underground roadway excavation is simulated by dynamic finite element modeling to analyze the effect of moisture content on the stability of the roadway. The results show that moisture content has a significant effect on shear properties reduction of both sandstone and mudstone, which must thus be considered in mining or excavation processes. Specifically, it is found that the number, area, and diameter of micropores, as well as surface porosity, increase with increasing moisture content. Additionally, stress concentration is negatively correlated with moisture content, while the influenced area and vertical displacement are positively correlated with moisture content. These findings may provide useful input for the design of underground roadways.

Effect of Bromus inermis Leyss Planting on Dynamic Changes of Soil Moisture Contents on the Bare Slope

2013 ◽  
Vol 807-809 ◽  
pp. 1648-1652
Author(s):  
Tie Jun Sun ◽  
Baderihu Tajilake
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Regulatory Mechanism ◽  
Dynamic Balance ◽  
Bromus Inermis ◽  
Dynamic Changes ◽  
Moisture Contents ◽  
Biological Characters ◽  
Underground Biomass

Experiment was executed to plant eco-grass of Bromus inermis Leyss on 15°bare slopes, and study effect of biological characters on dynamics of soil moisture contents. The results indicated that vegetation restored quickly on the bare slope after the eco-grass planted. There were 2473.4 kg/hm2 of overground biomass and 1744.1kg/hm2 of underground biomass, and 70% of underground biomass was in 0-10cm layer of soil. Meanwhile, there was a regulatory mechanism of soil moisture content for Bromus inermis Leyss. When rainfall was enough, soil moisture content in 0-80 cm layer could reach to the most of 26.83% quickly this year. Next it could decline near to the first value of 19.81% after rainfall stopped, and keep a dynamic balance between 19.48% and 19.96%. Moreover, the regulatory mechanism realized though underground biomass, and was clearer with underground biomass increasing, especially in the 0-40cm layer of soil.

Assessment of Moisture Content in Sandy Beach Environments from Multispectral Satellite Imagery

2021 ◽  
Author(s):  
Julie Paprocki ◽  
Nina Stark ◽  
Hans C Graber ◽  
Heidi Wadman ◽  
Jesse E McNinch
Keyword(s):  
Moisture Content ◽  
Laboratory Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sandy Beaches ◽  
Percent Error ◽  
Moisture Contents ◽  
Multispectral Satellite Imagery ◽  
Factor C

A framework for estimating moisture content from satellite-based multispectral imagery of sandy beaches was tested under various site conditions and sensors. It utilizes the reflectance of dry soil and an empirical factor c relating reflectance and moisture content for specific sediment. Here, c was derived two ways: first, from in-situ measurements of moisture content and average NIR image reflectance; and second, from laboratory-based measurements of moisture content and spectrometer reflectance. The proposed method was tested at four sandy beaches: Duck, North Carolina, and Cannon Beach, Ocean Cape, and Point Carrew, Yakutat, Alaska. Both measured and estimated moisture content profiles were impacted by site geomorphology. For profiles with uniform slopes, moisture contents ranged from 3.0%-8.0% (Zone 1) and from 8.0%-23.0% (Zone 2). Compared to field measurements, the moisture contents estimated using c calibrated from in-situ and laboratory data resulted in percent error of 3.6%-44.7% and 2.7%-58.6%, respectively. The highest percent error occurred at the transition from Zone 1 to Zone 2. Generally, moisture contents were overestimated in Zone 1 and underestimated in Zone 2, but followed the expected trends based on field measurements. When estimated moisture contents in Zone 1 exceeded 10%, surface roughness, debris, geomorphology, and weather conditions were considered.

Propagation velocity model of stress waves in larch wood (Larix gmelinii) three-dimensional space with different moisture contents

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6680-6695
Author(s):  
Xiwen Wei ◽  
Liping Sun ◽  
Hongjv Zhou ◽  
Yang Yang ◽  
Yifan Wang ◽  
...  
Keyword(s):  
Moisture Content ◽  
Wave Velocity ◽  
Stress Wave ◽  
Propagation Velocity ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Stress Waves ◽  
Moisture Contents ◽  
Direction Angle ◽  
Stress Wave Velocity

Based on the effects of stress wave propagation in larch (Larix gmelinii) wood, the propagation mechanism of stress wave was explored, and a theoretical model of the propagation velocity of stress waves in the three-dimensional space of wood was developed. The cross and longitudinal propagation velocities of stress wave were measured in larch wood under different moisture contents (46% to 87%, 56% to 96%, 20% to 62%, and 11% to 30%) in a laboratory setting. The relationships between the propagation velocity of stress waves and the direction angle or chord angle with different moisture contents were analyzed, and the three-dimensional regression models among four parameters were established. The analysis results indicated that under the same moisture content, stress wave velocity increased as the direction angle increased and decreased as chord angle increased, and the radial velocity was the largest. Under different moisture contents, stress wave velocity gradually decreased as moisture content increased, and the stress wave velocity was more noticeably affected by moisture content when moisture content was below the fiber saturation point (FSP, 30%). The nonlinear regression models of the direction angle, chord angle, moisture content, and the propagation velocity of stress wave fit the experiment data well (R2 ≥ 0.97).

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