scholarly journals Fully Hydrogenated and Fluorinated Bigraphenes–Diamanes: Theoretical and Experimental Studies

2021 ◽  
Vol 7 (1) ◽  
pp. 17
Author(s):  
Leonid A. Chernozatonskii ◽  
Victor A. Demin ◽  
Dmitry G. Kvashnin
Keyword(s):  
Raman Spectroscopy ◽  
Carbon Nanostructures ◽  
Recent Progress ◽  
Experimental Studies ◽  
Multilayer Graphene ◽  
Practical Realization ◽  
Atomic Structures ◽  
Theoretical Predictions ◽  
Potential Applications ◽  
Nanocrystal Films

Diamanes are 2D diamond-like films that are nanometers in thickness. Diamanes can exist as bilayer or multilayer graphene with various modes of stacking and interlayer covalent sp3 bonds. The term “diamane” is used broadly for a variety of diamond-like materials at the nanoscale, from individual diamond clusters to nanocrystal films. A short overview of recent progress in the investigation of diamanes, starting from the first theoretical predictions to practical realization, is presented. The results of both theoretical and experimental studies on diamanes with various atomic structures and types of functionalization are considered. It is shown that diamanes are stronger than graphene and graphane and have wide bandgaps ranging from 3.1 to 4.5 eV depending on the structure. Diamane-like structures have been obtained using different experimental techniques, and their structures have been determined by Raman spectroscopy. The potential applications of these carbon nanostructures are briefly reviewed.

scholarly journals Water Level Sensing in a Steel Vessel Using A0 and Quasi-Scholte Waves

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Peng Guo ◽  
Bo Deng ◽  
Xiang Lan ◽  
Kaili Zhang ◽  
Hongyuan Li ◽  
...  
Keyword(s):  
Water Level ◽  
Guided Waves ◽  
Mode Conversion ◽  
Experimental Studies ◽  
Low Frequency ◽  
Steel Vessel ◽  
Theoretical Predictions ◽  
Travelling Time ◽  
The Comparative Study ◽  
Group Velocities

This paper presents a water level sensing method using guided waves of A0 and quasi-Scholte modes. Theoretical, numerical, and experimental studies are performed to investigate the properties of both the A0 and quasi-Scholte modes. The comparative study of dispersion curves reveals that the plate with one side in water supports a quasi-Scholte mode besides Lamb modes. In addition, group velocities of A0 and quasi-Scholte modes are different. It is also found that the low-frequency A0 mode propagating in a free plate can convert to the quasi-Scholte mode when the plate has one side in water. Based on the velocity difference and mode conversion, a water level sensing method is developed. For the proof of concept, a laboratory experiment using a pitch-catch configuration with two piezoelectric transducers is designed for sensing water level in a steel vessel. The experimental results show that the travelling time between the two transducers linearly increases with the increase of water level and agree well with the theoretical predictions.

The Potential Applications of Raman Spectroscopy in Unravelling Complex Palaeowildfire Ecosystems

2021 ◽  
Author(s):  
Thomas Theurer ◽  
David Muirhead ◽  
David Jolley ◽  
Dmitri Mauquoy
Keyword(s):  
Raman Spectroscopy ◽  
Carbonaceous Material ◽  
Complex Interactions ◽  
Intensity Changes ◽  
Potential Applications ◽  
Ecosystem Studies ◽  
History Of ◽  
The Impact ◽  
Unique Relationship

<p>Raman spectroscopy represents a novel methodology of characterising plant-fire interactions through geological history, with enormous potential. Applications of Raman spectroscopy to charcoal have shown that this is an effective method of understanding intensity changes across palaeofire regimes. Such analyses have relied on the determination of appropriate Raman parameters, given their relationship with temperature of formation and microstructural changes in reference charcoals. Quantitative assessments of charcoal microstructure have also been successfully applied to the assessment of carbonaceous maturation under alternate thermal regimes, such as pyroclastic volcanism. Palaeowildfire systems in association with volcanism may present a complex history of thermal maturation, given interactions between detrital charcoals and volcanogenic deposition. However, whilst palaeofire and volcanic maturation of carbonaceous material are well understood individually, their interaction has yet to be characterised. Here we present the first analysis of palaeofire charcoals derived from volcanic ignition utilising Raman spectroscopy. Our results indicate that complex interactions between volcanism and palaeofire systems may be better understood by the characterisation of charcoal microstructure, alongside palaeobotanical and ecosystem studies. Understanding the unique relationship between wildfires and volcanism, and the impact that this has on the fossil record, may better assist our understanding of wildfire systems in deep history. Further still, this highlights the potential for better understanding the socioecological impacts of modern and future wildfire systems closely associated with volcanic centres. </p>

On vibration isolation of sandwich plate with periodic hollow tube core

2017 ◽  
Vol 21 (3) ◽  
pp. 1119-1132 ◽  
Author(s):  
Gui-Lan Yu ◽  
Hong-Wei Miao
Keyword(s):  
Vibration Isolation ◽  
Sandwich Plate ◽  
Experimental Studies ◽  
Low Frequency ◽  
Dispersion Relations ◽  
Frequency Responses ◽  
Vibration Attenuation ◽  
Potential Applications ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vibration isolation performance of a PC sandwich plate with periodic hollow tube core is investigated experimentally and numerically. The experiment results reveal that there exist vibration attenuation zones in acceleration frequency responses which can be improved by increasing the number of periods or tuning some structure parameters. The presence of soft fillers shifts the attenuation zone to lower frequencies and enhances the capability of vibration isolation to some extent. Dispersion relations and acceleration frequency responses are calculated by finite element method using COMSOL MULTIPHYSICS. The attenuation zones obtained by experiments fit well with that by simulations, and both are consistent with the band gap in dispersion relations. The numerical and experimental studies in the present paper show that this PC sandwich plate exhibits a good performance on vibration isolation in low frequency ranges, which will provide some useful references for relevant research and potential applications in vibration propagation manipulations.

scholarly journals The Effect of Cooling Water Mass Flow Rate Variations on the Heat Pipe Solar Collector Performance

2017 ◽  
Vol 5 (2) ◽  
pp. 31-41
Author(s):  
Abdulsalam D. M. Hassan ◽  
Rwaa Alaa Hussein
Keyword(s):  
Flow Rate ◽  
Solar Collector ◽  
Experimental Studies ◽  
Cooling Water ◽  
Percentage Increase ◽  
Cover Glass ◽  
Language Version ◽  
Theoretical Predictions ◽  
Useful Heat ◽  
Water Mass Flow Rate

The thermal performance of FPHPSC has been studied experimentally and theoretically. The collector consists of copper absorber plate, single glass cover, glass wool insulation and aluminum case. Ten wickless heat pipes of 12.7 mm inner diameter. The experimental studies of collector performance have been performed on four different CWMFR (0.03, 0.04, 0.05 and 0.06) kg/s. The relation between the amount of useful heat, instantaneous collector efficiency and solar intensity is discussed. The collector are tested under the climate condition of Kut city (32.6 latitude and 45.7 longitude). It is investigated that the increasing of CWMFR increase the efficiency of the collector. The percentage increase in the efficiency of the solar collector is in order of (13%), when the cooling water mas flow rate changes from 0.03 kg/sec to 0.06 kg/sec at (45o) collector tilt angle. A computer program based on VISUAL BASIC language (version 6) used for the theoretical analysis. The experimental results are in agreement reasonably with the theoretical predictions.

scholarly journals Modeling of formation of carbon cluster groups in electric arc discharge plasma

2018 ◽  
Vol 80 (2) ◽  
pp. 108-113 ◽  
Author(s):  
A. N. Gavrilov
Keyword(s):  
Carbon Nanostructures ◽  
Arc Discharge ◽  
Experimental Studies ◽  
Particle Method ◽  
Cost Effective ◽  
Carbon Cluster ◽  
Collision Integral ◽  
Numerical Calculations ◽  
Plasma Synthesis ◽  
Interelectrode Space

The problem of modeling complex resource-intensive processes of plasma synthesis of carbon nanostructures (CNS) on the basis of mathematical and numerical methods of solution, focused on the use of parallel and distributed computing for processing large amounts of data, allowing to investigate the relationship and characteristics of processes to obtain an effective, cost-effective method of synthesis of CNS (fullerenes, nanotubes), is an actual theoretical and practical problem. This article deals with the problem of mathematical modeling of motion and interaction of charged particles in a multicomponent plasma based on the Boltzmann equation for the synthesis of ONS by thermal sublimation of graphite. The derivation of the collision integral is presented allowing to perform a numerical solution of the Boltzmann - Maxwell equations system with respect to the arc synthesis of CNS. The high order of particles and the number of their interactions involved simultaneously in the process of synthesis of CNS requires significant costs of machine resources and time to perform numerical calculations on the constructed model. Application of the large particle method makes it possible to reduce the amount of computing and hardware requirements without affecting the accuracy of numerical calculations. The use of parallel computing technology on the CPU and GPU with the use of Nvidia CUDA technology allows you to organize all the General-purpose calculations for the developed model based on the graphics processor of the personal computer graphics card, without the use of supercomputers or computing clusters. The results of experimental studies and numerical calculations confirming the adequacy of the developed model are presented. Obtained quantitative characteristics of the total pairwise interactions between the carbon particles and interactions with the formation of clusters of carbon with various types of ties in the plasma of the interelectrode space which are the basis of the synthesized nanostructures. The formation of carbon clusters occurs in the entire interelectrode space of the plasma with different intensity and depends on the process parameters.

Carbon nano-onions: Unique carbon nanostructures with fascinating properties and their potential applications

2017 ◽  
Vol 468 ◽  
pp. 49-66 ◽  
Author(s):  
Olena Mykhailiv ◽  
Halyna Zubyk ◽  
Marta E. Plonska-Brzezinska
Keyword(s):  
Carbon Nanostructures ◽  
Potential Applications

Experimental studies of hydroxyapatite by Raman spectroscopy

2018 ◽  
Vol 85 (3) ◽  
pp. 130 ◽  
Author(s):  
P. E. Timchenko ◽  
E. V. Timchenko ◽  
E. V. Pisareva ◽  
M. Yu. Vlasov ◽  
L. T. Volova ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Experimental Studies
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