scholarly journals Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3513
Author(s):  
Vassilios Saltas ◽  
Despoina Pentari ◽  
Filippos Vallianatos
Keyword(s):  
Electrical Conductivity ◽  
Elevated Temperatures ◽  
Small Polaron ◽  
Complex Impedance ◽  
Bound Water ◽  
Data Representation ◽  
Industrial Applications ◽  
Mechanical And Thermal Properties ◽  
Wide Range ◽  
Complex Electrical Conductivity

The unique physicochemical, electrical, mechanical, and thermal properties of micas make them suitable for a wide range of industrial applications, and thus, the interest for these kind of hydrous aluminosilicate minerals is still persistent, not only from a practical but also from a scientific point of view. In the present work, complex impedance spectroscopy measurements were carried out in muscovite and biotite micas, perpendicular to their cleavage planes, over a broad range of frequencies (10−2 Hz to 106 Hz) and temperatures (473–1173 K) that have not been measured so far. Different formalisms of data representation were used, namely, Cole-Cole plots of complex impedance, complex electrical conductivity and electric modulus to analyze the electrical behavior of micas and the electrical signatures of the dehydration/dehydroxylation processes. Our results suggest that ac-conductivity is affected by the structural hydroxyls and the different concentrations of transition metals (Fe, Ti and Mg) in biotite and muscovite micas. The estimated activation energies, i.e., 0.33–0.83 eV for biotite and 0.69–1.92 eV for muscovite, were attributed to proton and small polaron conduction, due to the bound water and different oxidation states of Fe.

scholarly journals Bio-Based Polyurethane Resins Derived from Tannin: Source, Synthesis, Characterisation, and Application

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1516
Author(s):  
Manggar Arum Aristri ◽  
Muhammad Adly Rahandi Lubis ◽  
Apri Heri Iswanto ◽  
Widya Fatriasari ◽  
Rita Kartika Sari ◽  
...  
Keyword(s):  
Natural Resources ◽  
Value Added ◽  
Gel Permeation Chromatography ◽  
Industrial Applications ◽  
Hot Water ◽  
Synthesis Process ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Protective Function ◽  
Wide Range

Tannins are soluble, astringent secondary phenolic metabolites generally obtained from renewable natural resources, and can be found in many plant parts, such as fruits, stems, leaves, seeds, roots, buds, and tree barks, where they have a protective function against bacterial, fungal, and insect attacks. In general, tannins can be extracted using hot water or organic solvents from the bark, leaves, and stems of plants. Industrially, tannins are applied to produce adhesives, wood coatings, and other applications in the wood and polymer industries. In addition, tannins can also be used as a renewable and environmentally friendly material to manufacture bio-based polyurethanes (bio-PUs) to reduce or eliminate the toxicity of isocyanates used in their manufacture. Tannin-based bio-PUs can improve the mechanical and thermal properties of polymers used in the automotive, wood, and construction industries. The various uses of tannins need to be put into perspective with regards to possible further advances and future potential for value-added applications. Tannins are employed in a wide range of industrial applications, including the production of leather and wood adhesives, accounting for almost 90% of the global commercial tannin output. The shortage of natural resources, as well as the growing environmental concerns related to the reduction of harmful emissions of formaldehyde or isocyanates used in the production of polyurethanes, have driven the industrial and academic interest towards the development of tannin-based bio-PUs as sustainable alternative materials with satisfactory characteristics. The aim of the present review is to comprehensively summarize the current state of research in the field of development, characterization, and application of tannin-derived, bio-based polyurethane resins. The successful synthesis process of the tannin-based bio-PUs was characterized by Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), MALDI-TOF mass spectrometry, and gel permeation chromatography (GPC) analyses.

Bio-based polyhydroxyalkanoates blends and composites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Samy A. Madbouly
Keyword(s):  
Mechanical Properties ◽  
Functional Materials ◽  
Cost Effective ◽  
Production Method ◽  
Industrial Applications ◽  
Mechanical And Thermal Properties ◽  
Wide Range ◽  
High Production ◽  
High Production Cost ◽  
New Generation

Abstract Polyhydroxyalkanoates (PHAs) are linear semicrystalline polyesters produced naturally by a wide range of microorganisms for carbon and energy storage. PHAs can be used as replacements for petroleum-based polyethylene (PE) and polypropylene (PP) in many industrial applications due to their biodegradability, excellent barrier, mechanical, and thermal properties. The overall industrial applications of PHAs are still very limited due to the high production cost and high stiffness and brittleness. Therefore, new novel cost-effective production method must be considered for the new generation of PHAs. One approach is based on using different type feedstocks and biowastes including food byproducts and industrial and manufacturing wastes, can lead to more competitive and cost-effective PHAs products. Modification of PHAs with different function groups such as carboxylic, hydroxyl, amine, epoxy, etc. is also a relatively new approach to create new functional materials with different industrial applications. In addition, blending PHA with biodegradable materials such as polylactide (PLA), poly(ε-caprolactone) (PCL), starch, and distiller’s dried grains with solubles (DDGS) is another approach to address the drawbacks of PHAs and will be summarized in this chapter. A series of compatibilizers with different architectures were successfully synthesized and used to improve the compatibility and interfacial adhesion between PHAs and PCL. Finer morphology and significantly improvement in the mechanical properties of PHA/PCL blends were observed with a certain type of block compatibilizer. In addition, the improvement in the blend morphology and mechanical properties were found to be strongly influenced by the compatibilizer architecture.

scholarly journals Mechanical and Thermal Analyses of Metal-PLA Components Fabricated by Metal Material Extrusion

Inventions ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 44 ◽  
Author(s):  
Mahdi Mohammadizadeh ◽  
Hao Lu ◽  
Ismail Fidan ◽  
Khalid Tantawi ◽  
Ankit Gupta ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Thermal Analyses ◽  
Microstructural Analysis ◽  
Industrial Applications ◽  
Mechanical And Thermal Properties ◽  
Aluminum Powders ◽  
Material Extrusion ◽  
Metal Material ◽  
Wide Range ◽  
Metallic Parts

Metal additive manufacturing (AM) has gained much attention in recent years due to its advantages including geometric freedom and design complexity, appropriate for a wide range of potential industrial applications. However, conventional metal AM methods have high-cost barriers due to the initial cost of the capital equipment, support, and maintenance, etc. This study presents a low-cost metal material extrusion technology as a prospective alternative to the production of metallic parts in additive manufacturing. The filaments used consist of copper, bronze, stainless steel, high carbon iron, and aluminum powders in a polylactic acid matrix. Using the proposed fabrication technology, test specimens were built by extruding metal/polymer composite filaments, which were then sintered in an open-air furnace to produce solid metallic parts. In this research, the mechanical and thermal properties of the built parts are examined using tensile tests, thermogravimetric, thermomechanical and microstructural analysis.

A SYSTEMATIC STUDY ON THE DIELECTRIC RELAXATION, ELECTRIC MODULUS AND ELECTRICAL CONDUCTIVITY OF Al/Cu:TiO2∕n-Si (MOS) STRUCTURES/CAPACITORS

2020 ◽  
Vol 27 (10) ◽  
pp. 1950217
Author(s):  
M. YILDIRIM ◽  
A. KOCYIGIT
Keyword(s):  
Electrical Conductivity ◽  
Electric Modulus ◽  
Forward Bias ◽  
Industrial Applications ◽  
Dielectric Parameters ◽  
Mos Capacitors ◽  
Cu Doping ◽  
The Real ◽  
Complex Electric Modulus ◽  
Wide Range

The various levels (5%, 10% and 15%) of Cu-doped TiO2 thin films were grown on the [Formula: see text]-type silicon (Si) wafer by spin coating technique to obtain Al/(Cu:TiO[Formula: see text]/[Formula: see text]-Si (MOS) capacitors. Both the real and imaginary components of complex dielectric ([Formula: see text], complex electric modulus ([Formula: see text], loss tangent (tan [Formula: see text] and alternating electrical conductivity ([Formula: see text] of the obtained Al/(Cu:TiO[Formula: see text]-Si (MOS) capacitors were studied by taking into account the effects of Cu-doping levels into TiO2 viaimpedance spectroscopy method (ISM) in the wide range voltage ([Formula: see text][Formula: see text]V) and frequency (10[Formula: see text]kHz–1[Formula: see text]MHz). All the obtained dielectric parameters were obtained as strongly dependent on frequency, voltage and Cu doping level. The observed anomalous peak in the forward bias region both in the real and imaginary components of [Formula: see text], tan [Formula: see text], complex electric modulus ([Formula: see text] and [Formula: see text] were attributed to the Cu:TiO2 interlay er, series resistance ([Formula: see text], surface states ([Formula: see text], interfacial/surface and dipole polarizations. The higher values of [Formula: see text] at low and intermediate frequencies implied that [Formula: see text] have enough time to follow external ac signal, and also dipoles respond to the applied field to reorient themselves. Consequently, the fabricated Al/(Cu:TiO[Formula: see text]-Si can be successfully used as MOS capacitor or MOS-field-effect transistor (MOSFET) in the industrial applications in near future.

Dielectric properties, complex impedance and electrical conductivity of Fe2TiO5 nanopowder compacts and bulk samples at elevated temperatures

2016 ◽  
Vol 28 (6) ◽  
pp. 4796-4806 ◽  
Author(s):  
M. V. Nikolic ◽  
D. L. Sekulic ◽  
Z. Z. Vasiljevic ◽  
M. D. Lukovic ◽  
V. B. Pavlovic ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Properties ◽  
Elevated Temperatures ◽  
Complex Impedance

scholarly journals Development of a Device for Staged Determination of Water Activity and Moisture Content

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 881 ◽  
Author(s):  
Carlo Tiebe ◽  
Marc Detjens ◽  
Annika Fechner ◽  
Stefanie Sielemann ◽  
Andreas Lorek ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Bound Water ◽  
Free Water ◽  
Characteristic Parameter ◽  
Industrial Applications ◽  
Wide Range ◽  
Temperature Equilibrium

Moisture content and water activity are important parameters for quality characterizationof products like bulk materials, powders, granules. Thus, an exact determination is necessarilyrequired in a wide range of industrial applications. Moisture of materials is the content ofnon-chemically bound water in a solid or liquid. Water activity (aw) is a characteristic/parameter ofthe non-chemically bound (“free”) water in materials and is measured as humidity over asolid/liquid surface at constant temperature (equilibrium moisture content). It is an importantparameter to characterize the quality of e.g., pharmaceutical and food products. In ourcontribution, we present the developed MOISHUM device for staged determination of wateractivity and moisture content of liquid and solid materials.

scholarly journals Laser pyrolysis in papers and patents

2021 ◽  
Author(s):  
Christian Spreafico ◽  
Davide Russo ◽  
Riccardo Degl’Innocenti
Keyword(s):  
Carbon Dioxide ◽  
Electrical Conductivity ◽  
Additive Manufacturing ◽  
Biomedical Applications ◽  
Industrial Applications ◽  
Laser Pyrolysis ◽  
Laser Technologies ◽  
Wide Range ◽  
Scientific Papers ◽  
Application Fields

AbstractThis paper presents a critical review of laser pyrolysis. Although this technology is almost 60 years old, in literature many researchers, both from academia and industry, are still developing and improving it. On the contrary industrial applications are struggling to take off, if not in very restricted areas, although the technology has undoubted advantages that justify future development. The aim of this work consists in analysing a representative pool of scientific papers (230) and patents (121), from the last 20 years, to have an overview about the evolution of the method and try to understand the efforts spent to improve this technology effectively in academia and in industry. This study is important to provide a complete review about the argument, still missing in the literature. The objective is to provide an overview sufficiently broad and representative in the sources and to capture all the main ways in which laser pyrolysis has been used and with what distribution. The main focuses of the study are the analyses of the functions carried out by laser technologies, the application fields, and the types of used laser (i.e. models, power and fluence). Among the main results, the study showed that the main use of laser pyrolysis is to produce nanoparticles and coatings, the main materials worked by laser pyrolysis are silicon and carbon dioxide and the main searched properties in the products of laser pyrolysis are catalysts activity and electrical conductivity. CO2 lasers are the most used and the have high versatility compared to others. In conclusion, the study showed that laser pyrolysis is a consolidated technology within its main application fields (nanoparticles and coatings) for several years. Within this context, the technology has been developed on very different sizes and processes, obtaining a very wide range of results. Finally, these results may also have stimulated new areas of experimentation that emerged mainly in recent years and which concern biomedical applications, additive manufacturing, and waste disposal. Graphical abstract

scholarly journals CFD Modeling of Gas–Solid Cyclone Separators at Ambient and Elevated Temperatures

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 228 ◽  
Author(s):  
Mohammadhadi Nakhaei ◽  
Bona Lu ◽  
Yujie Tian ◽  
Wei Wang ◽  
Kim Dam-Johansen ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Cfd Simulation ◽  
Separation Efficiency ◽  
Flow Behavior ◽  
Industrial Applications ◽  
High Mass ◽  
Cfd Modeling ◽  
Solid Flow ◽  
Solids Loading ◽  
Wide Range

Gas–solid cyclone separators are widely utilized in many industrial applications and usually involve complex multi-physics of gas–solid flow and heat transfer. In recent years, there has been a progressive interest in the application of computational fluid dynamics (CFD) to understand the gas–solid flow behavior of cyclones and predict their performance. In this paper, a review of the existing CFD studies of cyclone separators, operating in a wide range of solids loadings and at ambient and elevated temperatures, is presented. In the first part, a brief background on the important performance parameters of cyclones, namely pressure drop and separation efficiency, as well as how they are affected by the solids loading and operating temperature, is described. This is followed by a summary of the existing CFD simulation studies of cyclones at ambient temperature, with an emphasis on the high mass loading of particles, and at elevated temperatures. The capabilities as well as the challenges and limitations of the existing CFD approaches in predicting the performance of cyclones operating in such conditions are evaluated. Finally, an outlook on the prospects of CFD simulation of cyclone separators is provided.

scholarly journals Mechanical and thermal characterization of tungsten particulate reinforced epoxy polymer composites

2021 ◽  
Author(s):  
Jenson Joseph. E ◽  
◽  
Kiran A.K ◽  
Panneerselvam K ◽  
◽  
...  
Keyword(s):  
Flexural Strength ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Thermal Characterization ◽  
Industrial Applications ◽  
Tungsten Particle ◽  
Mechanical And Thermal Properties ◽  
Matrix Composites ◽  
Scanning Calorimetry ◽  
Wide Range

Polymer matrix composites find a wide range of industrial applications due to its unique properties like lightweight, improved strength and the properties could also be tailored to suit specific applications. In this present work, a new class of polymer matrix composites with epoxy resin as matrix and tungsten metal particles as fillers were developed. The influence of the addition of tungsten fillers on mechanical and thermal properties of the composites has been investigated. The composites are fabricated by hand lay-up method and the specimens containing tungsten particle content by 1%, 3%, 5%, 7% and 9% by weight were developed. The developed specimens were subjected to mechanical and thermal investigations. Mechanical behavior was analyzed by conducting a flexural test and hardness as per ASTM standards. Thermal behavior was analyzed by conducting Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) of the developed composites. The results show that the addition of 7 wt. % filler has a higher value of flexural strength and hardness. Further addition of particulate fillers deteriorates the flexural strength and hardness due to agglomeration of filler content in the epoxy. Analysis by TGA and DSC shows that the thermal stability of composites is improved by increasing the addition of tungsten content in the epox.

scholarly journals Comparative Analysis and Biochemical Characterization of Two Endo-β-1,3-Glucanases from the Thermophilic Bacterium Fervidobacterium sp.

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 830 ◽  
Author(s):  
Burkhardt ◽  
Schäfers ◽  
Claren ◽  
Schirrmacher ◽  
Antranikian
Keyword(s):  
Elevated Temperatures ◽  
Biochemical Characterization ◽  
Hot Spring ◽  
Biomass Conversion ◽  
Catalytic Efficiency ◽  
Industrial Applications ◽  
Thermophilic Bacterium ◽  
Metagenomic Sample ◽  
Wide Range ◽  
Active Site Cleft

Laminarinases exhibit potential in a wide range of industrial applications including the production of biofuels and pharmaceuticals. In this study, we present the genetic and biochemical characteristics of FLamA and FLamB, two laminarinases derived from a metagenomic sample from a hot spring in the Azores. Sequence comparison revealed that both genes had high similarities to genes from Fervidobacterium nodosum Rt17-B1. The two proteins showed sequence similarities of 62% to each other and belong to the glycoside hydrolase (GH) family 16. For biochemical characterization, both laminarinases were heterologously produced in Escherichia coli and purified to homogeneity. FLamA and FLamB exhibited similar properties and both showed highest activity towards laminarin at 90 °C and pH 6.5. The two enzymes were thermostable but differed in their half-life at 80 °C with 5 h and 1 h for FLamA and FLamB, respectively. In contrast to other laminarinases, both enzymes prefer β-1,3-glucans and mixed-linked glucans as substrates. However, FLamA and FLamB differ in their catalytic efficiency towards laminarin. Structure predictions were made and showed minor differences particularly in a kink adjacent to the active site cleft. The high specific activities and resistance to elevated temperatures and various additives make both enzymes suitable candidates for application in biomass conversion.

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