scholarly journals Hydro-mechanical behaviour of sandy silt under generalised stress conditions

2016 ◽  
Vol 9 ◽  
pp. 14014
Author(s):  
Enrique Romero ◽  
Octavio E. Cárdenas ◽  
Antonio Lloret ◽  
Rodrigo C. Weber
Keyword(s):  
Mechanical Behaviour ◽  
Stress Conditions ◽  
Sandy Silt

scholarly journals Hydro-mechanical behaviour of a sandy silt from a river embankment

2020 ◽  
Vol 195 ◽  
pp. 01033
Author(s):  
Vincenzo Butticè ◽  
Alessio Ferrari ◽  
Carmine G. Gragnano ◽  
Guido Gottardi
Keyword(s):  
Mechanical Behaviour ◽  
Measurement Techniques ◽  
Degree Of Saturation ◽  
Confining Stress ◽  
River Level ◽  
Suction Control ◽  
Sandy Silt ◽  
Axial Translation ◽  
Safety Margins ◽  
River Embankment

The paper presents the results of an experimental campaign aimed at characterizing the hydro-mechanical behaviour of a sandy silt from a river embankment. Due to continuous river level fluctuations and changing climatic and environmental conditions, flood embankment materials experience frequent variations in degree of saturation and suction values. Such variations strongly impact the earthwork performance both in terms of seepage and stability conditions. For these reasons, a detailed characterization of the material behaviour in unsaturated conditions was carried out. Experiments were designed in order to highlight the response of the involved soil in terms of changes in matric suction and confining stress. All tests were performed on undisturbed samples from the embankment. To cover the suction range, which is expected to be significant for the material and assessed through field monitoring, a combination of several suction-control and suction-measurement techniques was used (e.g. negative water column, axial translation, tensiometers). Obtained results enabled (i) to quantify the evolution of the yield stress with suction, (ii) to assess the collapse upon wetting behaviour, (iii) to get detailed information on the water retention behaviour and (iv) to define the relative permeability of the soil. This extensive characterization work serves as a basis for the analysis of the embankment response following river level variations, the final purpose of the research being to establish a reliable methodology and a feasible procedure for the realistic assessment of the safety margins under transient seepage.

scholarly journals Influence of principal stress effect on deformation and permeability of coal containing beddings under true triaxial stress conditions

2019 ◽  
Vol 6 (2) ◽  
pp. 181438 ◽  
Author(s):  
Jiahui Dai ◽  
Chao Liu ◽  
Minghui Li ◽  
Zhenlong Song
Keyword(s):  
Mechanical Behaviour ◽  
Volumetric Strain ◽  
Bedding Plane ◽  
Stress Conditions ◽  
Triaxial Stress ◽  
Stress Effect ◽  
Direction Parallel ◽  
True Triaxial ◽  
Bedding Planes ◽  
True Triaxial Stress

In situ stress is generally an anisotropic/true triaxial stress ( σ 1 > σ 2 > σ 3 ). Bedding weakens the continuity and integrity of coal. It is critical to understand the mechanical behaviour and gas migration of coal under true triaxial stress conditions. We performed experiments of cubic coal samples to investigate the permeability evolution and mechanical behaviour of coal under true triaxial stress conditions by using newly developed true triaxial geophysical apparatus. We analysed the effect of principal stresses on deformation and permeability characteristics of coal containing bedding planes. The results show that volumetric strain, stress states and bedding directions determine the permeability comprehensively. The variable quantity of strain was the largest in the direction normal to the bedding plane. The expansion or compression degree was characterized by the difference between the major and minor principal strain ( ɛ 1 − ɛ 3 ). Essentially, this represents the difficulty degree with regard to coal being compressed at the initial stress state and the deformation degree in ɛ 1 and ɛ 3 direction. The variation of ( ɛ 1 − ɛ 3 ) was consistent with that of permeability. Under an identical true triaxial stress condition, permeability was smaller when larger stress was applied in the direction normal to the bedding plane. Additionally, stress level in the direction parallel to the bedding planes and the directions between stresses in the direction parallel to the bedding planes and the flow direction also affect the permeability and strain. By solving lateral expansion coefficient, coal also exhibited anisotropic properties.

Self-Injurious Behavior vs. Nonsuicidal Self-Injury

Crisis ◽  
2012 ◽  
Vol 33 (2) ◽  
pp. 106-112 ◽  
Author(s):  
Christopher M. Bloom ◽  
Shareen Holly ◽  
Adam M. P. Miller
Keyword(s):  
Positive Reinforcement ◽  
Empirical Investigation ◽  
High Stress ◽  
Animal Research ◽  
Stress Conditions ◽  
Human Populations ◽  
Pharmacological Interventions ◽  
Self Injury ◽  
Cns Stimulant ◽  
Nonsuicidal Self Injury

Background: Historically, the field of self-injury has distinguished between the behaviors exhibited among individuals with a developmental disability (self-injurious behaviors; SIB) and those present within a normative population (nonsuicidal self-injury; NSSI),which typically result as a response to perceived stress. More recently, however, conclusions about NSSI have been drawn from lines of animal research aimed at examining the neurobiological mechanisms of SIB. Despite some functional similarity between SIB and NSSI, no empirical investigation has provided precedent for the application of SIB-targeted animal research as justification for pharmacological interventions in populations demonstrating NSSI. Aims: The present study examined this question directly, by simulating an animal model of SIB in rodents injected with pemoline and systematically manipulating stress conditions in order to monitor rates of self-injury. Methods: Sham controls and experimental animals injected with pemoline (200 mg/kg) were assigned to either a low stress (discriminated positive reinforcement) or high stress (discriminated avoidance) group and compared on the dependent measures of self-inflicted injury prevalence and severity. Results: The manipulation of stress conditions did not impact the rate of self-injury demonstrated by the rats. The results do not support a model of stress-induced SIB in rodents. Conclusions: Current findings provide evidence for caution in the development of pharmacotherapies of NSSI in human populations based on CNS stimulant models. Theoretical implications are discussed with respect to antecedent factors such as preinjury arousal level and environmental stress.

Flavonoid profiling by LC-MS IN 14 – 3-3ν knockout mutants of Arabidopsis thaliana during drought stress conditions

Planta Medica ◽  
2014 ◽  
Vol 80 (10) ◽  
Author(s):  
F Nabbie ◽  
O Shperdheja ◽  
J Millot ◽  
J Lindberg ◽  
B Peethambaran
Keyword(s):  
Arabidopsis Thaliana ◽  
Drought Stress ◽  
Stress Conditions ◽  
Knockout Mutants

STRESS PADA LANSIA MENJADI FAKTOR PENYEBAB DAN AKIBAT TERJADINYA PENYAKIT

2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Nur Hidaayah
Keyword(s):  
Drinking Water ◽  
Free Radicals ◽  
The Elderly ◽  
The State ◽  
Young Age ◽  
Fresh Fruit ◽  
Stress Conditions ◽  
Harmful Substances ◽  
Available Resources

Stress conditions in the elderly means an imbalance condition of biological, psychological, and social are closely related to the response to the threats and dangers faced by the elderly. Pressure or interference that is not fun is usually created when the elderly see a mismatch between the state and the 3 systems available resources. Maintenance actions that need to be done there are 2 types, namely : prevention of exposure to a stressor (precipitation factor) and serious treatment of the imbalance condition/ illness (precipitation factor). Prevention includes: sports, hobbies, friendship, avoid eating foods high in free radicals and harmful substances, sex and setting arrangements adequate rest. Habits of the above if done at a young age to avoid exposure to stress in the elderly. Treatment of the imbalance condition / illness, include : drinking water, meditation, eating fresh fruit, and adequate rest.

Experimental Characterization of the Reliability of 3-Terminal Dual-Damascene Copper Interconnect Trees

2002 ◽  
Vol 716 ◽  
Author(s):  
C. L. Gan ◽  
C. V. Thompson ◽  
K. L. Pey ◽  
W. K. Choi ◽  
F. Wei ◽  
...  
Keyword(s):  
Stress Conditions ◽  
Experimental Characterization ◽  
Contact Lines ◽  
Tree Structures ◽  
Similar Test ◽  
Dual Damascene ◽  
Copper Interconnect ◽  
Test Conditions

AbstractElectromigration experiments have been carried out on simple Cu dual-damascene interconnect tree structures consisting of straight via-to-via (or contact-to-contact) lines with an extra via in the middle of the line. As with Al-based interconnects, the reliability of a segment in this tree strongly depends on the stress conditions of the connected segment. Beyond this, there are important differences in the results obtained under similar test conditions for Al-based and Cu-based interconnect trees. These differences are thought to be associated with variations in the architectural schemes of the two metallizations. The absence of a conducting electromigrationresistant overlayer in Cu technology, and the possibility of liner rupture at stressed vias lead to significant differences in tree reliabilities in Cu compared to Al.

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