scholarly journals Study on The Change Law of Wave Velocity and Porosity of Triaxial Loaded Coal

2020 ◽  
Author(s):  
donghui li ◽  
yanxia liang ◽  
shiqiang chen ◽  
kai zhang
Keyword(s):  
Wave Velocity ◽  
Confining Pressure ◽  
Testing System ◽  
Axial Pressure ◽  
Velocity Change ◽  
Porosity Change ◽  
Change Trend ◽  
The Relationship ◽  
The Voice ◽  
Safe Mining

Abstract The mechanical properties of loaded coal time to time, so that the voice wave propagation in coal changes with it. In order to study the relationship between the wave velocity of coal and its mechanical properties.The ultrasonic testing system was used to calculate the wave velocity of loaded coal at different times through laboratory triaxial loading test.The relationship between the wave velocity of loaded coal-body and the confining pressure of different coaxial pressures was analyzed.The results show that the wave velocity is positively correlated with the axial pressure under the same confining pressure. By calculating the variation of wave velocity of different loaded coal bodies. it is concluded that the variation of wave velocity of coal bodies can reflect the mechanical state of coal bodies undergo the compaction stage, the elastic stage and the new stage of crevasse. At the same time, the change of wave velocity in coal is affected by the porosity of the pressure-bearing coal-boby. Porosity was calculated using stress-strain.It was found that porosity and axial pressure presented a good negative correlation under the same confining pressure, and the change in wave velocity is exactly right opposite to the porosity change trend diagram.It can be obtained that the larger the amplitude of wave velocity change is, the smaller the porosity change is, and the smaller the amplitude of wave velocity change is, the larger the porosity change of coal body is, which is consistent with the actual analysis. It verifies the different the pressure-bearing coal-boby change in wave velocity to the feasibility of analyzing the mechanical condition of the loaded coal body. making the analysis more persuasive. It provides basis for coal body bearing and safe mining.

scholarly journals Correlation between seismic wave velocity, rock porosity and maximum principal stress based on the laboratory test data

2019 ◽  
Vol 39 (1) ◽  
pp. 37-46
Author(s):  
Jinfei Chai ◽  
Shunchuan Wu ◽  
Maria Tibbo
Keyword(s):  
Laboratory Test ◽  
Wave Velocity ◽  
Test Data ◽  
Seismic Wave ◽  
Crack Density ◽  
Density Parameter ◽  
Axial Pressure ◽  
Seismic Wave Velocity ◽  
Rock Porosity ◽  
The Relationship

In order to determine the internal relationships among seismic wave velocity, axial pressure, and rock porosity, the rock samples taken from NRS170143 borehole of the Nickel Rim South mine are tested using a Hoek type triaxial cell equipped with axial linear variable differential transducers (LVDTs) and a data acquisition module. The empirical expression between seismic wave velocity and rock pressure is fitted based on the laboratory test data of rock samples. Then, P-V model P-φ model and φ-ε model are created to analyze the laboratory test data. The results show that: (1) the relationship between axial pressure and rock porosity can be represented by a new empirical equation φ=a*e-b*P-c. With an increase of axial pressure, the value of rock porosity gradually decreases below the straight line φ=1% and close to 0. The P-φ model can be a good judge if the pressure has reached the maximum compression pressure in the process of rock compression experiment; (2) The P wave velocity and S wave velocity exponentially increase with increasing axial pressure; Rock porosity and crack density parameter exponentially decrease with increasing axial pressure; (3) there is a linear positive correlation between the ratio of rock porosity to crack density parameter and the ratio of crack thickness to crack length. (4) the relationship between Vp and Vs in each compression test can be fitted to the linear equation Vp=a*Vs+b; for all different samples of NR170143, the ratios (M) of Vp to Vs ranges from 1.35 to 1.85. In summary, the P-V model, P-φ model, φ-ε model and Vp-Vs-φ model can intuitively reflect the relationship among seismic wave velocity, axial pressure and rock porosity.

Shear Strength Monitoring System Based on Measurement of Shear Wave Velocity and Moisture Content

2014 ◽  
Vol 635-637 ◽  
pp. 750-754
Author(s):  
Peng Hu ◽  
Qing Li ◽  
Yi Wei Xu ◽  
Nan Ying Shentu ◽  
Quan Yuan Peng
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Shear Wave ◽  
Monitoring System ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Bender Elements ◽  
Strength Measurement ◽  
Soil Shear Strength ◽  
The Relationship

Expound the importance of soil shear strength measurement at mudslide hidden point to release the loss caused by the disaster, explain the relationship between shear wave velocity, moisture content and shear strength, design the shear strength monitoring system combining the shear wave velocity measured by Piezoelectric bender elements and moisture content.

scholarly journals The voice, text, and the visual as semiotic companions: an analysis of the materiality and meaning potential of multimodal screen feedback

2021 ◽  
Author(s):  
Clare Tyrer
Keyword(s):  
Student Teachers ◽  
Research Literature ◽  
Written Feedback ◽  
Feedback Process ◽  
Teachers Perceptions ◽  
Initial Teacher Training ◽  
The Relationship ◽  
The Voice ◽  
Structured Video

AbstractThe gap between how learners interpret and act upon feedback has been widely documented in the research literature. What is less certain is the extent to which the modality and materiality of the feedback influence students’ and teachers’ perceptions. This article explores the semiotic potential of multimodal screen feedback to enhance written feedback. Guided by an “Inquiry Graphics” approach, situated within a semiotic theory of learning edusemiotic conceptual framework, constructions of meaning in relation to screencasting feedback were analysed to determine how and whether it could be incorporated into existing feedback practices. Semi-structured video elicitation interviews with student teachers were used to incorporate both micro and macro levels of analysis. The findings suggested that the relationship between the auditory, visual and textual elements in multimodal screen feedback enriched the feedback process, highlighting the importance of form in addition to content to aid understanding of written feedback. The constitutive role of design and material artefacts in feedback practices in initial teacher training pertinent to these findings is also discussed.

The relationship between aortic augmentation index and pulse wave velocity: an invasive study

2007 ◽  
Vol 25 (2) ◽  
pp. 391-397 ◽  
Author(s):  
Masato Sakurai ◽  
Tetsu Yamakado ◽  
Hideshi Kurachi ◽  
Takaaki Kato ◽  
Kenji Kuroda ◽  
...  
Keyword(s):  
Pulse Wave Velocity ◽  
Wave Velocity ◽  
Pulse Wave ◽  
Augmentation Index ◽  
The Relationship

The voice of others: Identity, alterity and gender normativity among gay men in Israel

2012 ◽  
Vol 41 (2) ◽  
pp. 187-211 ◽  
Author(s):  
Erez Levon
Keyword(s):  
Lived Experience ◽  
Gay Men ◽  
Macro Level ◽  
Male Sexuality ◽  
Gay Identity ◽  
Social Categories ◽  
Gay Male ◽  
And Gender ◽  
The Relationship ◽  
The Voice

AbstractThis article presents an analysis of a slang variety, called oxtšit, as it is described and used by a cohort of gay men in Israel. Unlike many previous analyses of gay slang, I argue that the men described do not use the variety to help construct and affirm an alternative gay identity, but rather that they use it as a form of in-group mockery through which normative and nonnormative articulations of Israeli gay male sexuality are delineated. It is suggested that this discussion has implications for sociolinguistic understandings of “groupness” more broadly, and particularly the relationship between macro-level social categories (like “gay”) and individual lived experience. (Gay slang, Israel, vari-directional voicing, identity/alterity)*

Influence of powder characteristics on the properties of green compacts of Bi-2212 powders

1997 ◽  
Vol 12 (1) ◽  
pp. 21-27 ◽  
Author(s):  
D.-W. Yuan ◽  
M. D. Aesoph ◽  
J. Kajuch
Keyword(s):  
High Temperature ◽  
Confining Pressure ◽  
Plastic Behavior ◽  
Particle Sizes ◽  
Green Density ◽  
High Temperature Superconducting ◽  
Powder Characteristics ◽  
The Relationship ◽  
Powder In Tube ◽  
Superconducting Applications

With the growing potential for use of Bi-2212 powders in high temperature superconducting applications, it is important to understand the processing characteristics of the material. To meet this need, the present work established the relationship between confining pressure and green density for powders of different particle sizes and morphologies. Mechanical properties, including elastic and plastic behavior, of the resulting green compacts were also measured as a function of relative density. Particle size and size distribution are shown to have a significant impact on the properties of interest. The implications of such findings are discussed with respect to the powder-in-tube process for making high temperature superconducting wire and tape.

Stimme und Gebet

Rhetorik ◽  
2015 ◽  
Vol 34 (1) ◽  
Author(s):  
Andreas Hunziker
Keyword(s):  
Christian Theology ◽  
The Relationship ◽  
The Voice

AbstractThere is a long during controversy about the reception of the rhetoric tradition within Christian theology. The essay focuses on the question of the relationship between voice and prayer. Against the tradition of imagining prayer as an essentially mental and inner event, which may be in the background of the grüne Heinrich’s shame about his own voice, the author underlines the essential exteriority of prayer expressed paradigmatically in the voice of prayer. This relation between prayer and voice is shown in a conversation with Martin Luther’s and Jean-Louis Chrétien’s understanding of prayer.

A Study on Dynamic Properties of Cement-Stabilized Soils

2011 ◽  
Vol 243-249 ◽  
pp. 2050-2054 ◽  
Author(s):  
Pei Hsun Tsai ◽  
Sheng Huoo Ni
Keyword(s):  
Shear Modulus ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Confining Pressure ◽  
Test Results ◽  
Resonant Column Test ◽  
Stabilized Soil ◽  
Shearing Strain ◽  
Relationship Of ◽  
The Relationship

In this paper the dynamic property (shear modulus and damping ratio) of cement-stabilized soil is studied with using the resonant column test. The amount of cement admixed, the magnitude of confining pressure, and shearing strain amplitude are the parameters considered. Test results show that the maximum shear modulus of cement-stabilized soil increases with increasing confining pressure, the minimum damping ratio decreases with increasing confining pressure. The shear modulus of cement-stabilized soil decreases with increasing shearing strain while the damping ratio increases with increasing shearing strain. In the paper the relationship of shear modulus versus shearing strain is fitted into the Ramberg-Osgood equations using regression analysis.

The Coptic Church in Popular Fiction on the Eve of the Arab Spring:Youssef Ziedan’s Azazeel

2018 ◽  
Author(s):  
Nichole Perera
Keyword(s):  
Popular Fiction ◽  
The Novel ◽  
Academic Scholarship ◽  
The Subject ◽  
Coptic Church ◽  
Significant Addition ◽  
Theological Controversy ◽  
The Arab Spring ◽  
The Relationship ◽  
The Voice

The 5th century CE was a period of intense theological controversy concerning the relationship between the human and divine in Christ. This dispute led to the permanent separation of the Egyptian Coptic church from Imperial Orthodoxy. The events of the 5th century, previously confined to academic scholarship, have recently become the subject of popularizing works like Agora (2009), The Jesus Wars (2010), and 428 AD (2009). The Arabic novel Azazeel (2009), written by the Egyptian Islamic scholar Youseff Ziedan, is a significant addition to these other works. Like The Da Vinci Code in its use of “actual” historical evidence, Azazeel purports to be a compilation of newly discovered Syriac scrolls written by the Coptic monk Hypa, which detail his spiritual trials between 411 and 437 CE. The novel sparked great controversy in Egypt among Coptic Christians for creating a misleading picture of important figures and events in their early history. Copts felt that a Muslim scholar was appropriating the voice of a Coptic monk without clearly signalling it was a work of fiction in order to produce a false account of Coptic origins. Though published before the Arab Spring, it soon became further evidence of the oppressive intentions of the Muslim majority against a Coptic minority in Egypt. Azazeel is different from other similar works in English because the events of the 5th century are still part of the living identity of Copts.

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