Unveiling of Stishovite and Coesite in the Prismatine-Bearing Granulite from Waldheim, Germany: A Potential Role of Supercritical Fluids of Ultrahigh-Pressure Origin | Chapter 5 | Geography, Earth Science and Environment: Research Highlights Vol. 6

Stishovite, the tetragonal high-pressure polymorph of SiO2, was named by the Russian high-pressure physicist Sergey M. Stishov, who, together with Popova, first synthesized the mineral in 1961. This mineral is very rare at the Earth's surface, having only been found in known or suspected meteorite craters. For the first time in the sixty years since the synthesis of stishovite, unambiguous evidence of stishovite formed in the deep Earth has been reported. A minimum pressure of about 7.5 GPa at 1000 ◦C is necessary for the formation of stishovite, corresponding to a depth of about 230 km. The study reports the identification of stishovite and coesite as inclusions in mineral grains from the Waldheim granulite. This implies that the stishovite was transported upwards, probably very rapidly, to a depth of about 130 km, corresponding to the highest pressure indicated by newly identified coesite in the prismatine of the Waldheim granulite, and continuing up to the depth of emplacement of the Waldheim prismatine granulite. The analysis of the Raman spectra obtained from a metastable trapped stishovite micro-crystal shows that all the diagnostic Raman bands are present. However, given the metastability of the stishovite at room temperatures and pressures, this mineral breaks down step-by-step into stable polymorphs, first coesite and then quartz and cristobalite, during the Raman stimulation. The rare coesite crystals in prismatine have also resulted from the irreversible transformation from stishovite. Although the Waldheim occurrence may be unique, it can be suggested that Raman analysis of co-trapped crystals in similar deep-seated rocks, an area of limited previous research, may prove an essential innovation in the study of mantle processes. While the host rocks indicate no more than granulite facies temperatures and pressures, their minerals may contain co-trapped crystals from a much deeper source with higher temperatures and pressures.

 

Author (s) Details

 

Rainer Thomas
Raman laboratory, Im Waldwinkel 8, D-14662 Friesack, Germany.

 

Paul Davidson
Codes, Centre for Ore Deposits and Earth Sciences, University of Tasmania, Hobart 7001, Australia.

 

Adolf Rericha
Alemannenstraße 4a, D-144612 Falkensee, Germany.

 

Ulrich Recknagel
Böhmerwaldstraße 22, D-86529 Schrobenhausen, Germany.

 

 

Please see the book here:- https://doi.org/10.9734/bpi/geserh/v6/4527

Effect of Supercritical CO2 Fluid on Mechanical Properties of Hemp Fibers | Chapter 2 | Science and Technology - Recent Updates and Future Prospects Vol. 4

Hemp fibers have gained increasing attention these last years for their diverse applications, ranging from textiles to construction materials. However, the conventional methods of processing hemp fibers often involve harsh chemicals and high energy consumption, posing environmental concerns. In this context, the utilization of supercritical CO₂ (scCO₂) technology presents a promising alternative due to its environmentally friendly nature. This study aims to assess the efficiency of this technology for the pretreatment of hemp fiber materials, with a focus on evaluating fiber quality improvements. The obtained results show a promising quality of hemp fibers after this specific pretreatment, especially in the presence of a swelling agent. The scCO₂ treatment appeared to remove non-cellulosic compounds from the fiber, thereby resulting in an improvement in its appearance and a decrease in its linear density. We should continue this investigation through further studies since it is an environmentally benign process.

 

Author(s)details:-

 

Harrabi L
Université de Haute-Alsace, Mulhouse, France.

 

Almuhamed R
Université de Haute-Alsace, Mulhouse, France.

 

Drean JY
Université de Haute-Alsace, Mulhouse, France.

 

Please See the book here :- https://doi.org/10.9734/bpi/strufp/v4/11840F

Alternative Separation Process of Thermoplastic Polymer for Environmental Assessment | Chapter 11 | Recent Progress in Science and Technology Vol. 6

 In this paper, established processing and alternative modified procedures for polycarbonate production were defined and compared in terms of Environmental Performance Evaluation (PEP) to labeling opportunities to better environmental performance of polycarbonate result processes. Chemical industrial processes have enhance "business as usual," accompanying their energy-exhaustive production techniques and unsavoury honor. One example of an strength-intensive process that has grown expected one of ultimate important industrial processes is polycarbonate (PC). Additionally, abundant dangerous chemical compound are employed throughout all stages of its result. Environmental evaluation consists of process writing, hazard or chemical labeling, scenario identification to measure the impact or asperity and the probability of incident. The benefits of using SCF are related to the science's cleaner facets, minimization of raw material and strength consumption, decline of emissions and effluent discharge into the atmosphere, and maximisation of environmental benefits. Supercritical fluid harmlessly improves EPP while also considerably reducing pollutions. SCF's production of polycarbonates and conventional result techniques were distinguished for environmental performance. When distinguished to conventional designs, it was found that supercritical fluid technology has an effect on the decline of emissions. The research sexually transmitted disease in understanding the difficulties that the polycarbonate industry will encounter as synthetic emissions rise on account of increased production and strength use. A crucial and productive alternative tool is therefore wanted.

Author(s) Details:

Ibrahim Altuwair,
Northern Border University, Chemical and Materials Engineering, Arar, KSA and Centre for Safety, Risk and Integrity Engineering (C-RISE) Faculty of Engineering & Applied Science, Memorial University, NL, Canada.

Please see the link here: https://stm.bookpi.org/RPST-V6/article/view/9877

Characterization and Preparation of New Injectable Regenerative Acellular Dermal Collagen Microparticles via a Designed Combined Procedure of Supercritical Fluids and Protease Treatments at Low Temperatures | Chapter 13 | Highlights on Medicine and Medical Science Vol. 17

 Tissue engineering, which combines medical applications with engineering materials, was crucial. The tissue and cellular molecules from pig skin were extracted using a pretreatment of supercritical fluids and a devised combined approach of supercritical fluids of carbon dioxide and protease treatments at low temperatures in this work. Using protease reagent treatments, different porosities of decellularized tissues were created. The author used supercritical fluid and protease reagent treatments to characterise the intended decellularized scaffolds obtained from pig skins.

Author (S) Details

Ching-Cheng Huang
Department of Biomedical Engineering, Ming-Chuan University, Taiwan, Republic of China and PARSD Pharmaceutical Technology Research Center (PBMRC), Taiwan, Republic of China.

View Book :- https://stm.bookpi.org/HMMS-V17/article/view/2616

The Linear Chain Clusters in Real Gases | Chapter 3 | New Ideas Concerning Science and Technology Vol. 12

 The author's new class of linear chain clusters is described in this chapter, as well as the methods for evaluating their properties. There are two types of clusters in real gases: linear clusters with a small number of bonds between particles and closely bound two and three dimensional clusters. For several pure gases, the experimental data analysis reveals large temperature and density zones dominated by linear chain clusters. At moderate densities of real gases, expanding the possible energy density sequence by the monomer fraction density yields cluster bond parameters and their equilibrium constants, which can be attributed to this new class of clusters. The computer-aided study of precise thermophysical data for pure fluids using monomer fraction density reveals wonderful properties of these unknown cluster structures in real gases. Extrapolating the properties of these loosely bound clusters to higher densities yields a variety of tightly bound three-dimensional clusters in sub- and supercritical fluids in general, and particularly in CO2. It's crucial to understand the structure and parameters of the clusters in this gas, which is commonly used in supercritical fluid technologies. The properties of massive three-dimensional clusters of numbers n of particles up to the level of one thousand are discovered by moving from diluted to dense gases step by step. The soft structural transition between dominating cluster fractions with neighbour numbers n and between gas-like and liquid-like supercritical fluids is studied using a logarithmic method to estimate the averaged numbers n of particles in three-dimensional clusters.

Author (s) Details

Boris Sedunov
Computer and Information Systems Department, Russian New University, Moscow, Russia.

View Book :- https://stm.bookpi.org/NICST-V12/article/view/773