Evidence of a Unique Critical Fabric Surface for Granular Soils

Géotechnique ◽  
2021 ◽  
pp. 1-38
Author(s):  
Yuxuan Wen ◽  
Yida Zhang
Keyword(s):  
Critical State ◽  
Confining Pressure ◽  
Discrete Element Modelling ◽  
Large Strains ◽  
Granular Soils ◽  
Coordination Numbers ◽  
Strong Force ◽  
Wide Range ◽  
New Perspective ◽  
Fabric Surface

The critical state of granular soils needs to make proper reference to the fabric that develops at critical state. This study substantializes the concept of critical fabric surface (CFS) which attracts the fabric state of granular soils upon continuous shearing. Numerical experiments using discrete element modelling (DEM) are conducted under drained and undrained conditions with varies Lode angles. Fabric tensors are defined based on the normals of all contacts and of the strong force contacts only. Both tensors have their spherical component preserved such that the information of coordination number can be carried. A separate series of low confining pressure undrained test are conducted to probe the fabric states of soils in the post-liquefaction regime. Finally, a single CFS spanning across a wide range of coordination numbers is established based on the DEM results. The CFS concept provides an important reference state for soils sheared to large strains in complementary to the traditionally defined critical state. It provides a new perspective to interpret and model the mechanics of granular soils in both pre- and post- liquefied regimes. The evolution of fabric shows that the normalized strong-contact fabric evolves linearly with the stress ratio even for liquefied or anisotropically consolidated soils.

Socio-Semantic Processes in Social Actors Representation: A Case Study of “Ya-Sin”

2017 ◽  
Vol 15 (2) ◽  
pp. 145-169
Author(s):  
Roghayeh Farsi
Keyword(s):  
Case Study Approach ◽  
Academic Field ◽  
Social Actors ◽  
Study Approach ◽  
Wide Range ◽  
New Perspective ◽  
Linear Nature ◽  
Do So ◽  
Semantic Processes

AbstractThe academic field of Qurʾānic Studies employs a wide range of approaches, each one of which helps to open up a new perspective on the Qurʾānic text. The Holy Book was revealed to guide people; it is thus of relevance to all aspects of people’s lives. This article focuses on the way social actors are represented in one Meccansūra, entitled “Ya-Sin”, and employs a case-study approach to do so. The analysis carried out includes the socio-semantic processes that thesūrauses in order to represent social actors either by behavior (action) or meaning (reflection), and it also analyzes the actors as they are represented in processes such as activation and passivation. The methodology adopted is eclectic and analytic. It is a hybrid of Swales’ move analysis, El-Awa’s identification of shift-markers, and Halliday’s and Van Leeuwen’s theories of social actor representation. This study shows how such an analysis can contribute to understanding the apparently fragmented and non-linear nature of “Ya-Sin”.

Designing Soft Reactive Adhesives by Controlling Polymer Chemistry

MRS Bulletin ◽  
2003 ◽  
Vol 28 (6) ◽  
pp. 424-427 ◽  
Author(s):  
Agnès Aymonier ◽  
Eric Papon
Keyword(s):  
Automotive Industry ◽  
Ease Of Use ◽  
Large Strains ◽  
Structural Adhesives ◽  
Wide Range ◽  
Step Growth ◽  
Visible Irradiation ◽  
Step Growth Polymerization ◽  
Uv Visible ◽  
Activation Heat

AbstractSoft reactive adhesives (SRAs) are polymer-based materials (e.g., polyurethanes, polysiloxanes, polydienes) designed to be further vulcanized or slightly cross-linked through external activation (heat, moisture, oxygen, UV–visible irradiation, etc.), either at the time of their application or within a subsequent predefined period. They are used mainly as mastics, or sealing compounds, in a wide range of industrial and commercial fields such as construction, footwear, and the automotive industry. Generally deposited as thick films, SRAs behave as structural adhesives; their low elastic moduli accommodate large strains between the bonded parts without incurring permanent damage. Other outstanding attributes of SRAs are their resistance to solvents, their ability to withstand aggressive environments, and their ease of use. This article discusses examples of SRAs and, more specifically, shows how the cross-linking chemistry, mainly through step-growth polymerization, provides their primary advantages.

Effects of fines on liquefaction behaviour in well-graded materials

2017 ◽  
Vol 54 (10) ◽  
pp. 1460-1471 ◽  
Author(s):  
Katherine A. Kwa ◽  
David W. Airey
Keyword(s):  
Critical State ◽  
Soil Mechanics ◽  
State Parameter ◽  
Triaxial Tests ◽  
Particle Sizes ◽  
Graded Materials ◽  
Fines Content ◽  
Cyclic Resistance ◽  
Wide Range ◽  
Soil Behaviour

This study uses a critical state soil mechanics perspective to understand the mechanics behind the liquefaction of metallic ores during transport by ship. These metallic ores are transported at relatively low densities and have variable gradings containing a wide range of particle sizes and fines contents. The effect of the fines content on the location of the critical state line (CSL) and the cyclic liquefaction behaviour of well-graded materials was investigated by performing saturated, standard drained and undrained monotonic and compression-only cyclic triaxial tests. Samples were prepared at four different gradings containing particle sizes from 9.5 mm to 2 μm with fines (<75 μm) contents of 18%, 28%, 40%, and 60%. In the e versus log[Formula: see text] plane, where e is void ratio and [Formula: see text] is mean effective stress, the CSLs shifted upwards approximately parallel to one another as the fines content was increased. Transitional soil behaviour was observed in samples containing 28%, 40%, and 60% fines. A sample’s cyclic resistance to liquefaction depended on a combination of its density and state parameter, which were both related to the fines content. Samples with the same densities were more resistant to cyclic failure if they contained higher fines contents. The state parameter provided a useful prediction for general behavioural trends of all fines contents studied.

Thermal Response of a Viscoelastic Rod Under Cyclic Loading

1974 ◽  
Vol 41 (1) ◽  
pp. 229-233 ◽  
Author(s):  
S. Mukherjee
Keyword(s):  
Cyclic Loading ◽  
Thermal Response ◽  
Time History ◽  
Thermomechanical Coupling ◽  
Large Strains ◽  
Driving Frequency ◽  
Wide Range ◽  
History Of ◽  
Complex Young’S Modulus ◽  
Viscoelastic Rod

Thermal response of a viscoelastic rod under cyclic loading is discussed by determining the stresses and temperature in a viscoelastic rod insulated on its lateral surface and driven by a sinusoidal stress at one end. Temperature dependence of the complex Young’s modulus of the rod and the effect of thermomechanical coupling are included in the analysis. A method of finite differences is used to directly determine the steady-state stresses and temperature without obtaining the complete time history of the process. The iterative algorithm used is very efficient and converges rapidly for a wide range of driving stress amplitudes and frequencies. It is found that rapid rise of temperature to dangerous levels occurs for relatively low values of driving stress amplitudes, especially if the driving frequency is close to one of the critical frequencies of the rod. Drastic softening of the rod leads to large strains. Thus failure of the rod could occur at low values of the driving stress.

scholarly journals Characterization of an Insoluble and Soluble Form of Melanin Produced by Streptomyces cavourensis SV 21, a Sea Cucumber Associated Bacterium

Marine Drugs ◽  
2022 ◽  
Vol 20 (1) ◽  
pp. 54
Author(s):  
Joko Tri Wibowo ◽  
Matthias Y. Kellermann ◽  
Lars-Erik Petersen ◽  
Yustian R. Alfiansah ◽  
Colleen Lattyak ◽  
...  
Keyword(s):  
Biological Properties ◽  
Water Soluble ◽  
Soluble Form ◽  
Wide Range ◽  
Biological Form ◽  
Insoluble Form ◽  
New Perspective ◽  
Living Organisms ◽  
Purification Protocol

Melanin is a widely distributed and striking dark-colored pigment produced by countless living organisms. Although a wide range of bioactivities have been recognized, there are still major constraints in using melanin for biotechnological applications such as its fragmentary known chemical structure and its insolubility in inorganic and organic solvents. In this study, a bacterial culture of Streptomyces cavourensis SV 21 produced two distinct forms of melanin: (1) a particulate, insoluble form as well as (2) a rarely observed water-soluble form. The here presented novel, acid-free purification protocol of purified particulate melanin (PPM) and purified dissolved melanin (PDM) represents the basis for an in-depth comparison of their physicochemical and biological properties, which were compared to the traditional acid-based precipitation of melanin (AM) and to a synthetic melanin standard (SM). Our data show that the differences in solubility between PDM and PPM in aqueous solutions may be a result of different adjoining cation species, since the soluble PDM polymer is largely composed of Mg2+ ions and the insoluble PPM is dominated by Ca2+ ions. Furthermore, AM shared most properties with SM, which is likely attributed to a similar, acid-based production protocol. The here presented gentler approach of purifying melanin facilitates a new perspective of an intact form of soluble and insoluble melanin that is less chemical altered and thus closer to its original biological form.

scholarly journals On C-E Translation of Culture-Specific Items from the Perspective of Eco-translatology—A Case Study of Howard Goldblatt’s Red Poppies

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Xiaojun Zhang
Keyword(s):  
Material Culture ◽  
Chinese Culture ◽  
Three Dimension ◽  
Translation Study ◽  
Wide Range ◽  
Free Translation ◽  
Ecological Culture ◽  
Translation Methods ◽  
New Perspective

<div>This thesis researches the translation of Chinese culture-specific items in <em>Red Poppies</em> from the perspectives of Eco-translatology. Eco-translatology, which was put forward by Chinese scholar Hu Gengshen, adopts some concepts of ecology in translatology and provides a new perspective for translation study and practice. <em>Red Poppies</em> is a novel by Alai whose contents covers a wide range of Tibetan culture and history, which is praised as Tibetan encyclopedia. On one hand, the study focuses on the definition and features of culture-specific items, and their classification of in Red</div><div>Poppies. Based on Nida’s classification of five categories of sub-culture, those culture-specific items are classified into five groups, namely linguistic culture-specific items, material culture-specific items, ecological culture--specific items, social culture-specific items and religious culture-specific items. On the other hand, this thesis explores how Goldblatt deal with those culture-specific items from the perspective of three-dimension transformation in eco-translatology, and it finds translator adopts a combination of foreignization strategy and domestication strategy, and the former plays a dominating role. Besides, various translation methods are adopted such as free translation, transliteration, transliteration plus annotation, and amplification and so on.</div>

Nonlinear Dynamics of a Dielectric Elastomer Membrane Under Compressive Loading

2020 ◽  
Author(s):  
Robert L. Lowe ◽  
Christopher G. Cooley
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamic Response ◽  
Frequency Response ◽  
Compressive Loading ◽  
Excitation Frequency ◽  
Harmonic Excitation ◽  
Dielectric Elastomer ◽  
Large Strains ◽  
Membrane Stretch ◽  
Wide Range

Abstract This paper investigates the nonlinear dynamics of square dielectric elastomer membranes under time-dependent, through-thickness compressive loading. The dielectric elastomer is modeled as an isotropic ideal dielectric, with mechanical stiffening at large strains captured using the Gent hyperelastic constitutive model. The equation of motion for the in-plane membrane stretch is derived using Hamilton’s principle. The static response of the membrane is first investigated, with equilibrium stretches calculated numerically for a wide range of compressive pre-loads and applied voltages. Snap-through instabilities are observed, with the critical snap-through voltage decreasing with increasing compressive pre-load. The dynamic response of the membrane is then investigated under forced harmonic excitation. Frequency response plots characterizing the steady-state vibration reveal primary, subharmonic, and superharmonic resonances. Near these resonances, two stable vibration states are possible, corresponding to upper and lower branches in the frequency response. Significant and practically meaningful differences in the dynamic response are observed when the system vibrates at a fixed frequency about the upper and lower branches, a feature not discussed in previous research.

X-ray Diffraction Study of Amorphous NixZr(100-x)-Alloys Prepared by Melt-Spinning

1991 ◽  
Vol 46 (11) ◽  
pp. 947-950
Author(s):  
W.-M. Kuschke ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Melt Spinning ◽  
Pair Correlation ◽  
Nickel Concentration ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
Wide Range ◽  
Good Agreement

AbstractAmorphous Ni-Zr-alloys can be prepared by melt-spinning within a wide range of composition. Studies by X-ray diffraction yielded structure factors, pair correlation functions, total coordination numbers and atomic distances in dependence on the nickel concentration in the range of 25 up to 45 atomic percent. The change of the total coordination number and atomic distances turned out to be linear with the composition in this range. This is in good agreement with the linear composition dependence of the superconducting transition temperature, magnetic susceptibility, crystallization temperature, and electrical resistivity in the investigated range of composition.

On the Axial-Flexural-Torsional Coupling of Underwater Slender Cylinders

2012 ◽  
Author(s):  
Waldir T. Pinto ◽  
Carlos A. Levi
Keyword(s):  
Large Strains ◽  
Element Formulation ◽  
Algebraic Equations ◽  
Three Dimensional Model ◽  
Cylindrical Structures ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Torsional Coupling ◽  
Lift Forces ◽  
Drag And Lift

This paper presents a numerical model for the simulation of the axial-flexural-torsional coupling of undewater cylindrical structures. Cylindrical structures are largely utilized in the marine environment in a wide range of applications as in risers, marine cables, flexible pipes, mooring systems and so on. They may exhibit complex axial-flexural-torsional coupling, which makes the structural analysis highly nonlinear. In addition, the fluid-structure interaction may include flow induced vibrations, frequency lock-in and internal flow effects. The proposed three-dimensional model assumes that the structure aspect ratio is very high, its cross section is circular, the cable is elastic and may experience large displacements and large strains, as long as the elastic regime holds. The steady state load on the cylinder consists of the self-weight and buoyancy, drag and lift forces, in addition to a distributed residual twist along the cylinder. The drag and lift forces are evaluated by Morison type formulation. The governing differential equations are derived from first principles, assuming Newtonian mechanics. Then, they are solved numerically by a finite element formulation based on nonlinear space frame elements. The resulting set of algebraic equations is solved by a minimization technique that uses the Newton-Raphson algorithm. Results show the ability of the model to predict the static configuration of equilibrium of the cylinder and to capture the coupling between axial, flexural and torsional responses of the cylinder.

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