Investigations of Li-Picrate Salt Ion-pair to Ionic Dissociation in (PC+THF) at Various Combinations and Temperatures | Chapter 2 | Chemical and Materials Sciences: Developments and Innovations Vol. 9

 

Lithium perchlorate (LiClO4) is widely used as an electrolytic salt. Lithium perchlorate and other Li-salts have been used in the optimization of electrolyte solutions in organic aprotic solvents for primary and secondary rechargeable lithium batteries. Conductance of Li-Picrate was measured in different temperatures (25 oC, 35 oC, and 45 oC). The limiting equivalent conductance (𝜆0) and the ion association constant (KA) for Li-Picrate in propylene carbonate (PC) and tetrahydrofuran (THF) mixture (PC+THF) solvents at different percentages were evaluated using Debye-Huckel Onsager equation. It is observed that the limiting equivalent conductance increased linearly with the increase in temperature and the association constant values decreased with the rise in temperature. Thermodynamic parameters [i.e., Standard Gibbs Free Energy Change (iG0), Standard Enthalpy Change (iH0), and Standard Entropy Change (iS0) are estimated from the temperature dependence of the ion-association constant. The positive values of iS0 and positive values of iH0 indicate the ion-association process occurred spontaneously as well as endothermic at all respective temperatures. Supported by absorbance data from this primary study, it may be concluded that room temperature solubility of Li-Picrate in mixed (PC+THF) solvents at different percentages is higher than at higher temperatures. The entropy of ionization decreases slowly with an increase in temperature. From this angle, the ionization should decrease with temperature. Conductivity data helps us to conclude that if we go from room temperature to higher temperature conductance increases for Li-Picrate in (PC+THF) solvents at different percentages. This is due to the switchover of ion-pair to ionic dissociation of Li-Picrate salt.

 

Author(s) Details

 

Ashoke Hazra

Department of Chemistry, A.K.P.C. Mahavidyalaya, Subhasnagar, Bengai, Hooghly, India.

 

Please see the book here:- https://doi.org/10.9734/bpi/cmsdi/v9/3880

 

Algorithm for Pillar Stability Assessment Based on the Interaction Principle | Chapter 5 | Engineering Research: Perspectives on Recent Advances Vol. 5

The room-and-pillar mining method is a prevalent technique for extracting rock salt, potash, and magnesium salt deposits. This method creates a network of rooms (excavated areas) and pillars (supporting columns), requiring careful optimization of their dimensions and the surrounding rock mass properties for each unique geological setting. Because pillars bear the highest loads, their dimensions are typically the primary focus of the design process, influencing the dimensions of the rooms and other system components.  Specifically, for deep salt mining using square pillars, optimizing the system involves four key steps: (1) determining the in situ stress state (the stress field in the undisturbed rock mass); (2) analyzing the secondary stress distribution within the pillars, both qualitatively and quantitatively (how the stress changes after excavation); (3) assessing the load-bearing capacity of the pillars (how much weight they can support); and (4) determining the appropriate pillar dimensions (size and shape). Several analytical and numerical approaches can be used to address these challenges. These include: limit equilibrium methods, which consider the effective stress in the pillars; continuum mechanics, which uses analytical models to evaluate stress and deformation in pillars and floors; and numerical methods, such as finite element analysis, often validated with laboratory and field measurements. A proposed methodology, based on the principle of pillar-room-salt mass interaction, offers an analytical approach to determining the stability of deep, dry rock salt mining operations. This method calculates the secondary stress and deformation within the pillars, accounting for salt's time-dependent deformation (rheological behavior), changes in pillar geometry during extraction, and the specific extraction method employed. This analytical approach can be adapted for use in other mining applications that utilize the room-and-pillar method.

 

Author (s) Details

 

Mihaela TODERAS
Mining Engineering, Surveying and Constructions Department, University of Petrosani, Petrosani, Romania.

 

Please see the book here:- https://doi.org/10.9734/bpi/erpra/v5/4534

An Investigation into the Creep Behavior of Rock Salt from Slănic Prahova | Chapter 3 | Engineering Research: Perspectives on Recent Advances Vol. 2

The rheological behavior of rock salt, particularly creep deformation, significantly influences the stability of underground mining excavations. This study analyzes salt samples from the Slănic Prahova mine to characterize their rheological behavior and assess long-term excavation stability. Uniaxial compression tests revealed an increasing creep rate with increasing applied stress, following both exponential and power-law relationships. Impurities significantly influence the salt's rheological behavior, with higher NaCl content generally improving deformability. Creep mechanisms are complex, involving dislocation, diffusion, and polygonization processes. The salt from Slănic Prahova exhibits pronounced creep (Category 5), and empirical models better describe the observed behavior than constitutive models based on the theory of heredity. Rheological parameters such as modulus of elasticity, yield stress, creep rate, and creep coefficient, as well as the dilatation threshold, were determined. The mechanical properties of salt exhibit significant variability, with creep being the dominant deformation mechanism. Impurities and crystalline structure significantly influence the rheological behavior. The obtained results enable a more precise evaluation of mining excavation stability and highlight the need for more sophisticated numerical models to capture the non-linear behavior of salt.

 

Author (s) Details

 

Mihaela Toderas
Mining Engineering, Surveying and Civil Engineering Department, University of Petrosani, Petrosani, 20 University Street, Romania.

 

Ciprian Danciu
Mining Engineering, Surveying and Civil Engineering Department, University of Petrosani, Petrosani, 20 University Street, Romania.

 

Please see the book here:- https://doi.org/10.9734/bpi/erpra/v2/3891

Time-Dependent Cox Regression Analysis of Rock Salt | Chapter 7 | Advances and Challenges in Science and Technology Vol. 2

 The main objective concerning this study is to analyse and anticipate the potential risk of rock salt damage using the Cox equivalent hazard model. Analysed according to the belief of continuous mechanism medium rock massif is a natural environment troublesome to know, so the forecasts refer to its behaviour are approximate and changeable. Such an assertion enhances a certitude, even developing from reality; results of the four fundamental features of mountain system are multiple and include really troublesome issues in mining field and mainly, in the constructions field. The concept and the habit to assess the stability of secret construction includes understanding its phenomenological development and doubtless the personality of rocks behaviour in massif. Most of moment of truth, the analysis of the behaviour of the rocks and the chance of their breaking requires concern of the simultaneous belongings of several determinants. Rocks behave otherwise over time, and in any position, there is a feasibility that the break will manifest itself. Many times, we do not have complete information for the study of the resistance period of the rocks. To carry out aforementioned an analysis, we projected the use of a regressive means, that is, the Cox equivalent hazard model. By applying the Cox model or equivalent hazard regression, we have the feasibility of predicting the relative risk (potential risk) of the incident of rock breakage based on various variables. Risk (hazard) can have a different alternative, either in the sense that it can increase in time or possibly decrease; if over time skilled is no variable or determinant that determines an progress towards breaking the rock, then the risk of breaking is lower. Based on the standard scheme of rocks behaviour habit to failure, we are intend a statistical reasoning method of results acquired by laboratory tests using Cox reversion. This method offer the chance to provide quantitatively and qualitatively moment of truth when the breakage happens. The method allows us to establish the link betwixt a certain determinant through which maybe forecasted rock breakage and the talent to resist; the design can be grown and applied massif scale and again in the stability study of underground everything.

Author(s) Details:

Mihaela Toderas,
University of Petrosani, Petrosani-332006, Romania.

Please see the link here: https://stm.bookpi.org/ACST-V2/article/view/11930

Possibilities of Solving the Stability of Salt Strata Penetrated by Drilling: A Descriptive Study| Chapter 6 | Emerging Challenges in Environment and Earth Science Vol. 3

The rendering of oil structures apparent in the deep layers in Romania limits the penetration of some thick salt deposits (500-3,000 m) positioned above structures with petroleum potential (6,000 m). Drilling through these salt deposits is a major risk both during construction (drilling, cementing) and thereafter to ensure the wells' stability and dependability. These considerations shaped the approach to the salt deformation behaviour study challenge. The purpose of this article is to examine the following: salt behaviour deformation; establishment of the required parameters to ensure the stability of the drillings until bore-hole lining (particularly the secondary stress state around the drilling, the density of the drilling fluid in relation to temperature, respectively the depth), and also after casing (type of cement pastes, nature, quality, and pipe dimensions), namely the reliabilit The findings may aid in the selection of various options for guaranteeing the stability of boreholes that reach salt layers.

Author(s) Details:

Mihaela Toderas,
Department of Mining Engineering, Surveying and Constructions, University of Petrosani, Petrosani, 332006, Romania.

Please see the link here: https://stm.bookpi.org/ECEES-V3/article/view/6689