scholarly journals Yielding of a quartz sand from saturated to dry state

2020 ◽  
Vol 195 ◽  
pp. 03038
Author(s):  
Vincenzo Butticè ◽  
Alessio Ferrari ◽  
Marco Rosone
Keyword(s):  
Yield Stress ◽  
Quartz Sand ◽  
Degree Of Saturation ◽  
Experimental Program ◽  
Maximum Point ◽  
Wide Range ◽  
Points Of View ◽  
The One ◽  
The Relationship ◽  
Water Retention Behaviour

The paper presents the results of an experimental work where we analyse the behaviour of an unsaturated quartz sand in a wide range of degree of saturation (from saturated to dry state). The possibility of anticipating the hydro-mechanical behaviour of the soils when they approach the dry state is fundamental in many areas. An extensive experimental program, including controlled-suction and constant water content oedometric tests, was carried out to deeply analyse the water retention behaviour and the relationship between the yield stress and suction (Loading-Collapse curve). All elasto-plastic models provide a monotonically increase of the yield stress with suction. This assumption implies that the yield stress in the dry state is larger than the one relative to the saturated state, in contrast with the classical geotechnical points of view, which suggest that the yield stress of dry granular material must be approximately the same as that of the saturated one. The obtained results show that the yield stress of the sand does not increase monotonically with the suction, as predicted by commons models. In fact, the Loading - Collapse curve showed in this work presents a maximum point, and the yield stress for saturated condition is almost the same of the dried one.

scholarly journals To write or not to write: censorship in "The Woman in the Photo" by Tia Șerbănescu and "A Censor’s Notebook" by Liliana Corobca

2018 ◽  
Vol 1 (1) ◽  
pp. 8-27
Author(s):  
Monica Manolachi
Keyword(s):  
The Other ◽  
Literary Texts ◽  
Psychological Process ◽  
Production Of Knowledge ◽  
Mise En Abyme ◽  
Points Of View ◽  
The One ◽  
The Mind ◽  
The Relationship ◽  
Compare And Contrast

Censorship as a literary subject has sometimes been necessary in times of change, as it may show how the flaws in power relations influence, sometimes very dramatically, the access to and the production of knowledge. The Woman in the Photo: a Diary, 1987-1989 by Tia Șerbănescu and A Censor’s Notebook by Liliana Corobca are two books that deal with the issue of censorship in the 1980s (the former) and the 1970s (the latter). Both writers tackle the problem from inside the ruling system, aiming at authenticity in different ways. On the one hand, instead of writing a novel, Tia Șerbănescu kept a diary in which she contemplated the oppression and the corruption of the time and their consequences on the freedom of thought, of expression and of speech. She thoroughly described what she felt and thought about her relatives, friends and other people she met, about books and their authors, in a time when keeping a diary was hard and often perilous. On the other hand, using the technique of the mise en abyme, Liliana Corobca begins from a fictitious exchange of emails to eventually enter and explore the mind of a censor and reveal what she thought and felt about the system, her co-workers, her boss, the books she proofread, their authors and her own identity. Detailed examinations and performances of the relationship between writing and censorship, the two novels provide engaging, often tragi-comical, insights into the psychological process of producing literary texts. The intention of this article is to compare and contrast the two author’s perspectives on the act of writing and some of its functions from four points of view: literary, cultural, social and political.

Oedometric and water-retention behaviour of highly compacted unsaturated smectites

1999 ◽  
Vol 36 (4) ◽  
pp. 675-684 ◽  
Author(s):  
M Al-Mukhtar ◽  
Y Qi ◽  
J -F Alcover ◽  
F Bergaya
Keyword(s):  
Relative Humidity ◽  
Water Retention ◽  
Axial Stress ◽  
Degree Of Saturation ◽  
Experimental Program ◽  
Initial Void Ratio ◽  
Smectite Clays ◽  
Hydromechanical Behavior ◽  
Constant Axial Load ◽  
Water Retention Behaviour

This paper summarizes the findings from an experimental program concerning the hydromechanical behavior of two smectite clays tested under high stresses. Increasing axial stress on the smectite samples under controlled relative humidity (suction) leads to collapse in the soil structure and increases the degree of saturation. Irreversible volume change is observed in samples tested under cyclic suction with constant axial load. Water-retention (adsorption and desorption) behavior of the smectite clays tested in this study is affected by particle size, initial void ratio, and confinement conditions during the tests. Laponite, which has a large specific surface area, tends to hold more water than hectorite at a given relative humidity. More water is adsorbed by samples compacted at lower axial stress.Key words: smectite clays, hydromechanical stresses, behavior, relative humidity and suction, water retention, degree of saturation.

scholarly journals Investigation into water retention behaviour of deformable soils

2013 ◽  
Vol 50 (2) ◽  
pp. 200-208 ◽  
Author(s):  
Simon Salager ◽  
Mathieu Nuth ◽  
Alessio Ferrari ◽  
Lyesse Laloui
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Void Ratio ◽  
Degree Of Saturation ◽  
Retention Data ◽  
Soil Water Retention ◽  
Retention Behaviour ◽  
Wide Range ◽  
Water Retention Behaviour

The paper presents an experimental and modelling approach for the soil-water retention behaviour of two deformable soils. The objective is to investigate the physical mechanisms that govern the soil-water retention properties and to propose a constitutive framework for the soil-water retention curve accounting for the initial state of compaction and deformability of soils. A granular soil and a clayey soil were subjected to drying over a wide range of suctions so that the residual state of saturation could be attained. Different initial densities were tested for each material. The soil-water retention curves (SWRCs) obtained are synthesized and compared in terms of water content, void ratio, and degree of saturation, and are expressed as a function of the total suction. The studies enable assessment of the effect of the past and present soil deformation on the shape of the curves. The void ratio exerts a clear influence on the air-entry value, revealing that the breakthrough of air into the pores of the soil is more arduous in denser states. In the plane of water content versus suction, the experimental results highlight the fact that from a certain value of suction, the retention curves corresponding to different densities of the same soil are convergent. The observed features of behaviour are conceptualized into a modelling framework expressing the evolution of the degree of saturation as a function of suction. The proposed retention model makes use of the theory of elastoplasticity and can thus be generalized into a hysteretic model applicable to drying–wetting cycles. The calibration of the model requires the experimental retention data for two initial void ratios. The prediction of tests for further ranges of void ratios proves to be accurate, which supports the adequacy of formulated concepts.

Variation of Initial Soil Suction with Compaction Conditions for Clayey Soils

2012 ◽  
Vol 28 (3) ◽  
pp. 431-437 ◽  
Author(s):  
S.-R. Yang ◽  
H.-D. Lin ◽  
W.-H. Huang
Keyword(s):  
Water Content ◽  
Clay Fraction ◽  
Degree Of Saturation ◽  
Soil Suction ◽  
Clayey Soils ◽  
Test Results ◽  
Wide Range ◽  
Initial Soil ◽  
Compaction Energy ◽  
The Relationship

AbstractIn this study, the initial soil suction of as-compacted clayey soils was evaluated for various compaction conditions, covering a wide range of compaction energy and molding water content. The soil specimens were prepared by impact compaction under three levels of compaction energy. The filter paper method was used to measure the initial soil suction of as-compacted specimens. Test results indicate that the relationship between the soil suction and the molding water content is bilinear under three different compaction energies. However, the effect of compaction energy on soil suction is different for the soils with different amounts of clay fraction and is elucidated by the macro soil properties. The change of soil suction due to different compaction energies can be predicted by the void ratio and the degree of saturation.

A Viscoelastic Model for the Dynamic Behavior of Saturated Poroelastic Soils

1992 ◽  
Vol 59 (1) ◽  
pp. 128-135 ◽  
Author(s):  
J. P. Bardet
Keyword(s):  
Elastic Moduli ◽  
Viscoelastic Model ◽  
Degree Of Saturation ◽  
Biot Theory ◽  
One Dimensional ◽  
Poroelastic Materials ◽  
Proposed Model ◽  
Wide Range ◽  
Dynamic Loadings ◽  
The One

A viscoelastic model is proposed to describe the dynamic response of the saturated poroelastic materials that obey the Biot theory (1956). The viscoelastic model is defined from the velocity and attenuation of dilatational and distortional waves in poroelastic materials. Its material properties are defined in terms of the elastic moduli, porosity, specific gravity, degree of saturation, and permeability of the soils. The proposed model is tested by comparing its response with the one of poroelastic materials in the case of axial and lateral harmonic loadings of one-dimensional columns. The viscoelastic model is simpler to use than poroelastic materials but yields similar results for a wide range of soils and dynamic loadings.

Physical and numerical modeling of infiltration including consideration of the pore-air phase

2014 ◽  
Vol 51 (12) ◽  
pp. 1475-1487 ◽  
Author(s):  
G.A. Siemens ◽  
W.A. Take ◽  
S.B. Peters
Keyword(s):  
Pore Pressure ◽  
Geotechnical Engineering ◽  
Degree Of Saturation ◽  
Richards Equation ◽  
Experimental Program ◽  
Soil Physics ◽  
Air Entrapment ◽  
Wide Range ◽  
Cover Systems ◽  
The Impact

Infiltration is a vadose zone process of interest to a wide range of research communities including agriculture, soil physics, and geotechnical engineering. In geotechnical engineering, transient infiltration is important to moisture balance problems such as cover systems, capillary breaks, and landslide triggering. Design of cover systems, capillary breaks, and landslide analysis applications depend on accurate models for the transient pore pressure and moisture migration response under a wide range of environmental conditions. Infiltration is typically modeled using Richards’ equation, which assumes no impedance from the pore-air phase. However, if this assumption is invalid, the ground response during infiltration is significantly affected. An optically matched pore fluid – transparent soil, which allows for high temporal and resolution measurements of degree of saturation, was used to examine the effect of air entrapment on infiltration. Homogeneous and layered profiles were subjected to closed and open infiltration conditions. Following the completion of the experimental program, the results were simulated using a finite element program that allows for consideration of the air phase during infiltration. The results show the impact of ignoring the effect of air entrapment is to significantly underpredict the time to saturation and overpredict the pore pressure response.

scholarly journals The relationship between creativity and mental illness: a systematic review

2021 ◽  
Author(s):  
Tayebeh Ourtani
Keyword(s):  
Systematic Review ◽  
Mental Illness ◽  
Mental Disorders ◽  
Grey Literature ◽  
Large Body ◽  
British Library ◽  
Controversial Issues ◽  
Wide Range ◽  
The One ◽  
The Relationship

The association between creativity and mental disorders has been a subject of long-standing debate. And it is one of the most controversial issues in the field of creativity and psychopathology research. Despite the fact that engaging in creative activities has a wide range of benefits for mental health the concept of creativity/ mental illness has been widespread. On the one hand, a large body of anecdotal and empirical supports this association (e.g.Simonton, 2010; Andreasen, 2008; Johnson et al., 2012). On the other hand, some scholars argued that the creativity/ psychopathology connection is a traditional legend, and the empirical research in this area has many shortcomings, especially in terms of methodology (e.g. Sawyer, 2012; Schlesinger, 2009).This study conducted a systematic review to investigate the link between creativity and mental illness. Various electronic databases were used to find selected studies: including, Google Scholar, PubMed (Medline), Science Direct, and PMC (NCBI). Also, British Library, Core, and EThOS were applied to search for grey literature. In this paper, 24 studies have been reviewed that they are involved 6,525,664 participations. 21 reviewed studies provided some indications to support a positive link between creativity and psychopathology. 1 study proposed a negative link, and two studies suggested that there is no relationship. Altogether, the results displayed that there is a significant positive correlation between creativity and sub-clinical mental disorders. According to this study, not only creativity was introduced as a by-product of certain sub-clinical mental disorders (e.g., bipolar disorder, schizotypy) but it also identified as a treatment for some severe mental disorders (e.g., depression and addiction).

scholarly journals INFLUENCE OF HYDROGEN ON PLASTIC FLOW OF THE TITANIUM AND ITS ALLOYS

2017 ◽  
Vol 23 (2) ◽  
pp. 122 ◽  
Author(s):  
Alexey Ovchinnikov ◽  
Svetlana Skvortsova ◽  
Andrey Mamonov ◽  
Eugene Yermakov
Keyword(s):  
Phase Composition ◽  
Titanium Alloys ◽  
Yield Stress ◽  
Test Method ◽  
Management Tool ◽  
Research Approach ◽  
Commercial Titanium ◽  
Wide Range ◽  
The One ◽  
Hydrogen Alloying

<p>The relevance is established by the widespread titanium application in the modern machine engineering on the one hand, on the other hand – by low manufacturability. In this context, this article is aimed to exposure fundamental laws of the reversing hydrogen alloying for the titanium alloys manufacturability improvement during the plastic yield process.</p><p>Deformability of titanium alloys, formation of the structure and properties during deformation and the influence of hydrogen on these processes has been extensively studied recently [1-14].</p><p>The leading research approach is to determine stress-related characteristics by the compression-test method at the isothermal conditions and then to compare the results for three different alloys: commercial titanium, α - Ti-6Al alloy and α+β – Ti-6Al-4V alloy. Hydrogen alloying is also used as a flexible phase composition management tool for the investigated alloys.</p><p>In this paper the effect of hydrogen as an alloying element on the yield stress in commercial titanium and Ti-6Al and Ti-6Al-4V alloys is investigated. The connection is made between the strain resistance and phase composition in the wide range of temperatures. It has been found that the hydrogen alloying of commercial titanium in the α-field is accompanied by the yield stress decrease. The role of volume phase ratio in the alloys softening in α+β-field has been shown. The hydrogen hardening parameters in α-field are defined.</p><p>The paper materials are of a usage value for researchers and technologists, developing innovative technological processes of strained semi-finished titanium products manufacturing.</p>

scholarly journals Directors’ board, R&D investment and the firm’s performance: Evidence from the French case

2014 ◽  
Vol 10 (2) ◽  
pp. 85-101 ◽  
Author(s):  
Zouari Ghazi ◽  
Zouari-Hadiji Rim
Keyword(s):  
Corporate Governance ◽  
Board Of Directors ◽  
The Other ◽  
Double Structure ◽  
The Board Of Directors ◽  
French Case ◽  
Points Of View ◽  
The One ◽  
The Relationship ◽  
D Investment

This study examines the relationship between the board of directors and firm performance in terms of the level of R&D investment in the French context and some corporate governance points of view. Our model seeks to show whether the level of investment in R&D acts as an intermediary variable between, on the one hand, the dominance of external directors, the double structure and size of the board of directors, and, on the other, productivity. This empirical study is based on a sample of 178 French firms for the period 2008-2012. The results of the linear regression show that the relationship between the variables associated with the composition of the board of directors and the effectiveness of the company depends on the level of investment of the company in R&D.

scholarly journals Book Review

1984 ◽  
Vol 1 (1) ◽  
pp. 123-126
Author(s):  
Sulayman S. Nyang
Keyword(s):  
North Africa ◽  
Common Elements ◽  
Islam And Politics ◽  
Wide Range ◽  
African Socialism ◽  
The Common ◽  
The One ◽  
Definition Of ◽  
The Relationship

Reviewed by: Sulayman S. Nyang, Ph.D.Associate Professor of Government and Public AdministrationHoward University, Washington, D.C. 20059David WESTERLUND, From Socialism to Islam? Notes on Islam as aPolitical Factor in Contemporary Africa .R esearch Report No. 61.(Uppsala, Sweden: Scandinavia Institute of African Studies, 1982),62pp. Bibliography. No Price.This short study on Islam and Politics in Africa is one of a series ofstudies on Africa published by the well-known Swedish Institute ofAfrican Studies. The Center had previously published some excellentmonographs on a wide range of African issues, but this is the first one onan Islamic theme. Written from the perspective of a researcherinterested in knowing the future of the relationship between Islam andPolitics in Africa, David Westerlund divides his essay into three parts:(1) an introduction, (2) a section on the advance of Socialism in Muslimdominatedcountries and (3) a section on the move towards Islam.Westerlund begins his study with a definition of terms and aclarification of concepts. Two terms, Socialism and Islam, dominate hisdiscussion. He identifies socialism in North Africa and in Sub-SaharanAfrica as that brand which has not been based on, but rather opposed to,Marxism or Marxism-Leninism. Though he recognizes certaindifferences between “Arab Socialism” and “African Socialism”, in thecontext of his discussion he stresses the similarities between them.Among the common elements shared by these two variants of Socialismare (1) refutation of the Marxist idea of class struggle, (2) emphasis on aunited front of all classes in the interest of economic developrflent andnation-building, (3) a preference for a mixed economy as opposed to aMarxist economy, (4) partial nationalization, central planning and onepartyrule, and (5) tolerance of private property.After an examination of the differences between Arab/IslamicSocialism and African Socialism on the one hand, and Marxism on theother, Westerlund then discusses the term fundamentalism. Hecorrectly notes that orthodox, non-secularist Muslims who wish for the ...

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