A Roadmap for the Chalcogenide-graphene Composites Formation Under a Glassy Regime

2020 ◽  
Vol 3 (1) ◽  
pp. 49-55
Author(s):  
Abhay Kumar Singh ◽  
Tien-Chien Jen

Background: Nano-composite is an innovative material having nano in which fillers dispersed in a matrix. Typ-ically, the structure is a matrix- filler combination, where the fillers like particles, fibers, or fragments are surrounded and bound together as discrete units by the matrix. The term nano-composite encompasses a wide range of materials right from three dimensional metal matrix composites to two dimensional lamellar composites. Therefore, the physical, chemical and biological properties of nano materials differ from the properties of individual atoms and molecules or bulk matter. The chalcogenide – graphene composites in glassy regime is the growing novel research topic in the area of composite material science. It is obvious to interpret such materials different physicochemical mechanism. Objective: The key objective of this research work to explore the internal physicochemical mechanism of the chalcogenide – graphene composites under the glassy regime. Including the prime chalcogen alloying element selenium amorphous atomic structure and their fullerene like bonding nature. By accommodating the essential properties of the stacked layers of bilayer graphene. The diffusion, compression and dispersion of the bilayer graphene in selenium rich ternary (X(1-x-y)-Y(x)- Z(y) + GF (bilayer graphene); X = Se, Y = Semimetal or metalloid, Z = None metal) alloys under the complex regime on and after thermal melting process are addressed. Materials and Methods: To synthesize the composite materials the well-known melt quenched method had adopted. More-over, to interpret the amorphous selenium (Se8) chains and rings molecular structures we had used vista software with an available CIF data file. While to show the armchair and zig-zag bonds with bilayer graphene structure the nanotube modeler simulation software has used. Results: Outcomes of this study reveals the chalcogenide -graphene nano composite formation under a glassy regime changes the individual materials structural and other physical properties that is reflecting in different experimental evi-dences, therefore, the modified theoretical concepts for the different properties of such composite materials are interpreted in this study. Discussion: The dispersion and diffusion of the high stiff graphene bonds in low dimension chalcogen rich alloys has been interpreted based on their quadric thermal expansion behaviour. In addition to this, a possible bond angle modification in the formation of X(1-x-y)-Y(x)- Z(y) + GF composites are also addressed. To interpret the distinct optical property behavior of the formed X(1-x-y)-Y(x)- Z(y) + GF composites and parent chalcogenide glassy alloys a schematic model of the energy levels is also addressed. Conclusion: To make a better understating on the formation mechanism such composites, the diffusion and deformation of high stiff graphene σ and π bonds in a low dimension chalcogenide alloy basic mechanism are discussed on basis of novel “thermonic energy tunneling effect” concept, which could result in quadratic thermal expansion of graphene. Moreover, the structural unit modifications of such composite materials are described in terms of their bond angle modifications and in-fluence of the coordination defects. The energy levels suppression and creation of addition sub energy levels in such com-posite materials are discussed by adopting the viewpoint impact of the foreign alloying elements and surface π-plasmonic resonance between the graphene layers in the honeycomb band structure. Thus, this study has described various basic aspects of the chalcogenide system – bilayer graphene composites formation under a glassy regime.

Author(s):  
A. Delfini ◽  
A. Anwar ◽  
R. Pastore ◽  
L. Bassiouny ◽  
M. Marchetti ◽  
...  

2015 ◽  
Vol 1101 ◽  
pp. 79-82
Author(s):  
B.C. Suresh ◽  
S.B. Arun

Now a day’s composite materials are taking very important role in industrial growth. Composite materials are widely used in Automobiles, aerospace, submarine and also in other major fields, due to their special characteristics like light weight, high strength, stiffness, corrosion resistance. The determination of Coefficient of Thermal Expansion (CTE) of MMCs is important to aid its usage in high temperature environment as in the case of automobile combustion chamber. In these applications the stability of the composites over a long period of operation is a critical design considerationPresent work deals with the thermal property evaluation of the Al alloy / alumina metal matrix composite developed using the Stir Casting with chilling route technique. LM 26 Al alloy is being selected as the matrix material as it is a potential alloy for automotive piston applications. Al alloy / alumina MMCs was cast under end chilling technique by dispersing the reinforcement from 6 to 12 wt% the steps of 3% to study the variation in its thermal properties. At the same time chill material is also changed (Copper and MS) for different composition of MMCs cast to study the thermal behavior variations. After casting the required MMC, test specimens were prepared as per the standards to conduct thermal conductivity (K) tests and coefficient of thermal expansion (CTE) tests. Above tests were repeated for different composites containing different weight % of dispersed cast using different chills.


2013 ◽  
pp. 117-125
Author(s):  
K Dimitrov ◽  
T Döhler ◽  
M Herzog ◽  
S Schrader ◽  
S Nenkova

2020 ◽  
Vol 57 (1) ◽  
pp. 299-305
Author(s):  
Ruxandra Margarit ◽  
Livia Alice Tanasescu ◽  
Dana Bodnar ◽  
Camelia Gabriela Ion ◽  
Mihai Burlibasa ◽  
...  

The aim of our study was to compare the fracture resistance of teeth presenting non-carious cervical lesions restored with different types of esthetic composite materials. 20 extracted unspoiled maxillary first molars were mechanically cleaned and immersed in saline solution containing 0.1% thymol at 4�C for a period of 48 hours. Cervical cavities with a cervical-occlusal diameter of 2 mm and a mesial-distal diameter of 3mm were filled with ormocer, flow nano-composite, nano-composite and compomer. Fracture resistance was tested with a universal loading machine (Lloyd Instruments), with a maximum force of 5 kN and a crosshead speed of 1.0 mm/min; the authors used NEXYGEN Data Analysis Software and ANOVA method. For the group A (commercial grade ormocer), the smallest load that determined the sample failure was 650 N and the highest load was 1050 N, the mean value being 858 N � 150.89 N. For the group B (commercial grade flow nano-composite), the smallest load is 530 N, the highest load is 800 N, mean value being 654 N � 112.6 N. For the group C (commercial grade nano-composite), the smallest load is 680 N, the highest load is 1200 N, mean value being 926 N � 209.35 N. For the group D (commercial grade compomer), the smallest load is 1100 N, highest load is 1250N, mean value being 1180 N � 62.04 N. A p value of 0.000311 (p[0.05) shows that there are significant differences between the four groups. Conclusions. The best fracture resistance of teeth presenting non-carious cervical lesions, restored with different types of esthetic composite materials is assured by the compomer, followed by the nano-composite, which proved to be superior to ormocer. The flow nano-composite gives the lowest fracture resistance.


2021 ◽  
pp. 167-180
Author(s):  
M. A Tashkinov ◽  
A. D Dobrydneva ◽  
V. P Matveenko ◽  
V. V Silberschmidt

Сomposite materials are widely used in various industrial sectors, for example, in the aviation, marine and automotive industries, civil engineering and others. Methods based on measuring the electrical conductivity of a composite material have been actively developed to detect internal damage in polymer composite materials, such as matrix cracking, delamination, and other types of defects, which make it possible to monitor a composite’s state during its entire service life. Polymers are often used as matrices in composite materials. However, almost always pure polymers are dielectrics. The addition of nanofillers, such as graphene and its derivatives, has been successfully used to create conductive composites based on insulating polymers. The final properties of nanomodified composites can be influenced by many factors, including the type and intrinsic properties of nanoscale objects, their dispersion in the polymer matrix, and interphase interactions. The work deals with modeling of effective electric conductive properties of the representative volume elements of nanoscale composites based on a polymer matrix with graphene oxide particles distributed in it. In particular, methods for evaluating effective, electrically conductive properties have been studied, finite element modelling of representative volumes of polymer matrices with graphene oxide particles have been performed, and the influence of the tunneling effect and the orientation of inclusions on the conductive properties of materials have been investigated. The possibility of using models of resistive strain gauges operating on the principle of the tunneling effect is studied. Based on the finite-element modeling and graph theory tools, we created approaches for estimating changes in the conductive properties of the representative volume elements of a nanomodified matrix subjected to mechanical loading.


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