Spatial Variability of Mechanical Properties of Sedimentary Rocks in the Jiu Valley Basin: A Stress-strain Curve Analysis | Chapter 6 | Research Advances in Environment, Geography and Earth Science Vol. 10

The study aimed to evaluate the geomechanical characteristics of sedimentary rocks in the Jiu Valley coal basin, with the purpose of providing relevant data for the design and execution of mining works under safe conditions. A significant number of rock samples were analyzed, representative of the various lithological types and zones of the basin. Laboratory tests were conducted to determine the mechanical behavior of rocks under load, with a focus on strength, deformability, and failure mode. The results obtained highlighted a significant heterogeneity of geomechanical properties, influenced by factors such as mineralogical composition, geological structure, and degree of alteration. The study identified that the sedimentary rocks in Jiu Valley can be classified according to strength into three main categories: very low-strength rocks, low-strength rocks, and medium-strength rocks. A close correlation was also observed between the mechanical behavior of rocks and the presence of structural defects, such as fissures and fractures. A detailed analysis of stress-strain curves allowed the identification of two main types of behavior: elastic, with work hardening, and inelastic, characteristic of low-strength rocks. These differences in behavior have important implications for the stability of mining works, influencing the mode of crack propagation and deformations induced by mining. In conclusion, the study highlighted the geomechanical complexity of sedimentary rocks in the Jiu Valley basin. The obtained data can be used to develop more accurate numerical models and to optimize the design of mining works, thus contributing to increasing the safety and efficiency of mining operations in this area. Through extensive laboratory and field investigations, coupled with analytical studies, we have obtained objective data on the geomechanical laws governing the rock mass. These findings allow for a quantitative and qualitative description of its deformation behavior, aiding in the understanding of stress conditions and facilitating the development of new methods to ensure the stability of mining operations. These studies focused on determining the characteristics of strength and deformation necessary to classify these rocks and facilitate the study of their rheological behavior.

 

Author (s) Details

Mihaela Toderas
Mining Engineering, Surveying and Civil Engineering Department, Faculty of Mines, University of Petrosani, 332006 Petrosani, Romania.

 

Please see the book here:- https://doi.org/10.9734/bpi/raeges/v10/2783

Redefining Big Bang Cosmology with a Fresh Perspective | Chapter 10 | Current Perspective to Physical Science Research Vol. 4

 Professed the homogeneity and isotropy of the universe at large sizes is a challenging task. This episode aims to explore the impact of matter distribution in uniformity up to the last uneven surface time within the foundation of spatially homogeneous yet anisotropic models. These models produce anisotropies on large bent scales (larger than 𝜗 > 2°) that closely mirror those found in the conventional FriedmannLemaitre-Robertson-Hiker (FLRW) geometries.Regarding these anisotropic models, the imprint abandoned on the cosmic microwave history radiation on account of primordial density vacillations, manifested as fractional hotness variations, understands the same expression as in FLRW models. Just, under adiabatic initial conditions, we obey the retrieval of the simple Sachs-Wolfe effect, as the anisotropy in the overall cosmic expansion debris minimal concurrently with an activity of the last scattering surface.This finding joins with prior research on these anisotropic models, signifying their gradual "isotropization" in a way where observational qualities from FLRW models become imperceptible, in order that the Hubble parameters ahead orthogonal directions are nearly equal to their current principles. In conclusion, the observation of Sachs-Wolfe effect level does not permit us to distinguish between FLRW models and the anisotropic Kantowski-Sachs and Bianchi type-III models. This work also settled upper bounds on the anisotropic limits' present-day values established COBE observations.

Author(s) Details:

Paulo Aguiar,
Universidade Lusíada do Porto, Rua de Moçambique 21 e 71, 4100-348 Porto, Portugal.

Please see the link here: https://stm.bookpi.org/CPPSR-V4/article/view/12635

Synthesis, Consolidation and Significant Enhancement in Thermoelectric Properties of Ca3Co4O9 Bulk Ceramics by Adding Silver Combine Spark Plasma Texturing | Chapter 6 | Current Innovations in Chemical and Materials Sciences Vol. 1

 The objective concerning this work is the significant augmentation of the thermoelectric properties of Ca3Co4O9 size ceramic by an creative process ‘Spark plasma Texturing’ (SPT) capable to integred into thermoelectric device. The work existed in synthesizing Ca3Co4O9 compound by substituting Ca2+ cations accompanying Ag+ cations, or by adding large silver in the Ca3Co4O9 step in order to impose upon the metallic type of silver and the effect of composition to optimize the power determinant (PF) and the figure of merit (ZT). The thermoelectric performance (for either capacity generation or chilling) depends on the efficiency of the thermoelectric material for transfering heat into electricity. The adeptness of a thermoelectric material depends primarily on the thermoelectric matters figure-of-merit, known as zT (0). The XRD dossier have shown that bigger phase is the Ca3Co4O9 individual, accompanied by silvery Ag phase, that shows that Ca3Co4O9//Ag compound is composite.  Both the traditional habit of synthesizing response in the solid state and the contemporary texturing approach famous as Spark Plasma Texturing (SPT), which connects the directed type of Hot Pressing (HP) and the Spark Plasma Sintering (SPS) method, were handled. Grain sizes and preferred introduction perpendicular to the important axis are told by microstructural examination of sintered pellets created by SPT. These grains are considerably bigger in magnitude than those produced by SPS. Consequently, the study acquired a maximum PF value 555μW.m-1 K-2  at 900 K, that is among high-quality reported about constitute materials and a period saving of 98% distinguished to Hot Pressing (HP).

Author(s) Details:

Jerome Dikwa,
College of Technology, The University of Ngaoundere, P.O. Box 455, Ngaoundere, Cameroon and Faculty of Science, The University of Yaounde 1, P.O. Box 812, Yaounde, Cameroon.

Jean-Marie Bienvenu Ndjaka,
Faculty of Science, The University of Yaounde 1, P.O. Box 812, Yaounde, Cameroon.

Danwe Raidandi,
National Advanced School of Engineering, The University of Yaounde 1, P.O. Box 8390, Yaounde, Cameroon.

Simon Quetel-Weben,
CRISMAT-ENSICAEN Laboratory, UMR CNRS 6508, 14050 CeanCedex, France.

Pierre Owono Ateba,
Faculty of Science, The University of Yaounde 1, P.O. Box 812, Yaounde, Cameroon.

Please see the link here: https://stm.bookpi.org/CICMS-V1/article/view/11875

Evaluation of the Integral Scale and Fractal Dimension in Stratified Turbulent Flows | Chapter 1 | Emerging Issues in Environment, Geography and Earth Science Vol. 1

 The construction of the turbulent flows in the air boundary coating (ABL) is irregular, accompanying fluid mechanical quantities vacillate in a disordered form, with tiers of wind that moves at different speeds. The study of this construction can be observed in succession of wind velocities, the irregular behaviour of these flows is on account of the superimposed of waves and agitation onto a mean wind. These vacillations are also on account of a broad range of scales from the smallest to the best scales corresponding to the basic scale, where the moving power is maximum. The fractal dimension of wind parts determines those flow irregularities and is a bitter flow characteristic. It is of interest in this work to analyse the equating between the fractal measure and integral scale. The mean principles of these two magnitudes are related to climatic stability and imbalance. The stratification of the fierce flow is evaluated accompanying the Bulk Richardson number. We investigate during the occurring every day and night eras how the elemental scale and fractal dimension of the elements (u') horizontal and (w') upright velocity influences in layered turbulent flows. The scales are acquired using affecting animate nerve organs anemometer dossier from three elevations 5.8 m, 13 m and 32 m above the ground measured all along the SABLES- 98 field campaign. These components have happened calculated utilizing the mean wind direction as foundation. The integral scale has happened estimated utilizing a method that integrates the normalized autocorrelation function and the best Gaussian fit (R2≥ 0.70). The effects of doubtful thermal lamination in diurnal hours increase the average principles of the integral scale and fractal measure of both parts. During the nights, the existence of the resistant stratification decreases the complete scale with increase in fractal measure. These variations of the average principles for u' horizontal component maybe adjusted to the straight reversion line and for w' vertical component the average principles have fit a quadratic function accompanying R2≥ 0.80, in most of the fits. The elemental scale for the u' component varies middle from two points around 100 m on their tinier scales and above 1500 m for their larger scales. The complete scales for w' component are slightly lower than for the u' component betwixt a few tens of beat and 1000 m. Finally, we study the anisotropy of the turbulent flows by equating the scales of u` and w` velocity elements at the same altitude.

Author(s) Details:

Manuel Tijera,
Applied Mathematics Department (Biomathematics), Complutense University of Madrid, Madrid, Spain.

Gregorio Maqueda,
Astronomy, Astrophysics and Atmospheric Science Department, Complutense University of Madrid, Madrid, Spain.

Please see the link here: https://stm.bookpi.org/EIEGES-V1/article/view/11821

Anomalous Properties of Magnetocaloric Effect and Magnetic Order in Gd2InGe2 | Chapter 8 | Fundamental Research and Application of Physical Science Vol. 8

We calculated the electrical transport, thermal, and drawing properties of antiferromagnetic (TN = 45 K) Gd2 InGe2. Magnetization ahead the c-axis at 0.5 K, using beat magnetic field up to 45 T, checked the possibility metamagnetic changes. Magnetization measurements under applied magnetic field of currents, oriented parallel and straight to c-axis, and heat capacity dossier were used to extract the anisotropic magnetocaloric effect, using Maxwell’s relations. Our results indicate a model of magnetic arranging where Gd local moments couple ferromagnetically steep, and antiferromagnetically parallel to the c-axis. From the reasoning of the electrical transport, heat competency, and magnetization, conduction band electrons are weakly connected to Gd f-electron local importance.

Author(s) Details:

A. L. Lima-Sharma,
Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.

A. M. Gomes,
Laboratório de Baixas Temperaturas, Inst. de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-909, Brazil.

P. A. Sharma,
Department of Quantum Phenomena, Sandia National Laboratories, Albuquerque, USA.

Please see the link here: https://stm.bookpi.org/FRAPS-V8/article/view/11683

Thermal Deformation and Strength of Materials for Heat-shielding Coatings of a Spacecraft on the Trajectory of Descent from Orbit| Chapter 8 | Techniques and Innovation in Engineering Research Vol. 2

 The basis for a fundamental understanding of the process of material interaction with a medium is the agreement between experimental research and the actual operating conditions of a specific model or structure. Thermal Shield Materials (TSMs) are designed based on certain requirements, such as the characteristics of heating and material destruction under the least amount of shield weight. The more useful space load it can give, the lighter it must be. Since the thermal shield serves as a missile's ballast weight, it is only natural to want to lower the weight of TSMs without sacrificing their capacity to reliably perform their thermal shield role. Utilizing calculations based on the physical characteristics of materials discovered during conditions replicating a spacecraft's re-entry into the atmosphere, the performance of thermal shield structures was examined. The dependence of the temperature T of a thermal shield side surface on the period of descent in dense air layers serves as the basis for physical modelling of the natural conditions of thermal shield use (temperature, heating/cooling rate, composition, and pressure of gas medium). A thermal barrier was made composed of a laminated fibreglass shell with a phenol-phormaldehyde matrix. Investigations were done on temperature-dependent mechanical and thermophysical characteristics. By using numerical analysis, elasticity theory, and thermal conductivity equations to solve a 3D problem, it is possible to characterise the thermally stressed state of a cylindrical shield that is being impacted by a high-temperature gas flow. According to the results, the maximum compression stresses in a fibreglass thermal shield shell are located close to the heated surface and are not higher than the material's strength limit at that temperature. A new, 30% lighter thermal protection system for the re-entry vehicle was proposed and put into practise as a result of the experimental and theoretical investigations that were conducted.

Author(s) Details:

Lyudmila I. Gracheva,
G. S. Pisarenko Institute for Problems of Strength, National Academy of Sciences of Ukraine, Kiev - 01014, Ukraine.

Please see the link here: https://stm.bookpi.org/TAIER-V2/article/view/8276

Analyzing the Effect of Energy Anisotropy on Electromagnetic Ordinary Mode and Purely Transverse Extraordinary Mode | Chapter 12 | New Trends in Physical Science Research Vol.3

The effects of energy anisotropy on the Ordinary mode (O-mode) and the exclusively transverse Extraordinary mode have been investigated (X-mode). The generic dispersion relations for O-mode and X-mode have been developed using kinetic theory. Energy anisotropy, magnetic field to density ratio (_0/ p), and plasma beta _ were used to calculate the stability condition and growth rates. The growth rates and stability of the abovementioned modes demonstrate the dependence of stability on plasma beta and energy anisotropy T /T_. The energy anisotropy T /T_ and the marginal threshold plasma beta. The marginal threshold O-mode, as well as the oscillatory and merely increasing modes' reliance on energy anisotropy, are diametrically opposed. The X-mode, on the other hand, meets the instability criterion due to the geometry difference with the O-Mode. For spherical tokamaks, these modes are significant because their coupling leads to the production of the Bernstein mode, which provides the heating effects.

Author(s) Details:

N. Noreen,
Forman Christian College (Chartered University), Ferozpur Road, 54000 Lahore, Pakistan.

S. Zaheer,
Forman Christian College (Chartered University), Ferozpur Road, 54000 Lahore, Pakistan.

H. A. Shah,
Forman Christian College (Chartered University), Ferozpur Road, 54000 Lahore, Pakistan.

Please see the link here: https://stm.bookpi.org/NTPSR-V3/article/view/6831