Littérature scientifique sur le sujet « CYLINDRICAL CNT »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les listes thématiques d’articles de revues, de livres, de thèses, de rapports de conférences et d’autres sources académiques sur le sujet « CYLINDRICAL CNT ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Articles de revues sur le sujet "CYLINDRICAL CNT"
1
Nam, Vu Hoai, Nguyen Thi Phuong et Vu Minh Duc. « Nonlinear buckling of orthogonal carbon nanotube-reinforced composite cylindrical shells under axial compression surrounded by elastic foundation in thermal environment ». International Journal of Computational Materials Science and Engineering 08, no 04 (décembre 2019) : 1950016. http://dx.doi.org/10.1142/s2047684119500167.
Texte intégralRésumé :
Nonlinear buckling and postbuckling of orthogonal carbon nanotube-reinforced composite (Orthogonal CNTRC) cylindrical shells subjected to axial compression in thermal environments surrounded by elastic foundation are presented in this paper. Two layers of shell are reinforced by carbon nanotube (CNT) in two orthogonal directions (longitudinal and circumferential directions). Based on Donnell’s shell theory with von Karman’s nonlinearity and the Galerkin method, the governing equations are established to obtain the critical buckling loads and postbuckling load-deflection curves. The large effects of CNT volume fraction, temperature change, elastic foundation and geometrical parameters of cylindrical shells on the buckling load and postbuckling behavior of Orthogonal CNTRC cylindrical shells are obtained.
2
Alibeigloo, A., et H. Jafarian. « Three-Dimensional Static and Free Vibration Analysis of Carbon Nano Tube Reinforced Composite Cylindrical Shell Using Differential Quadrature Method ». International Journal of Applied Mechanics 08, no 03 (avril 2016) : 1650033. http://dx.doi.org/10.1142/s1758825116500332.
Texte intégralRésumé :
In this paper, bending and free vibration analysis of carbon nanotubes reinforced composite (CNTRC) cylindrical shell is carried out using the three-dimensional theory of elasticity. The single-walled carbon nanotubes (SWCNT) reinforcement is either uniformly distributed (UD) or functionally graded (FG) in the thickness direction which, are specified as the cases [Formula: see text], [Formula: see text], [Formula: see text] and FG-X. Effective material properties of CNTRC cylindrical shell are estimated according to the rule of mixture as well as considering the CNT efficiency parameters. An analytical solution is performed by using Fourier series along the axial coordinate together with state space technique along the radial coordinate for the simply supported CNTRC cylindrical shell. Moreover, for CNTRC cylindrical shell with other edges boundary conditions, a semi-analytical solution is accomplished by using differential quadrature method (DQM) along the axial coordinate and state space technique along the radial coordinate. Present approach is validated by comparing the numerical results with the available published results. Furthermore, effect of types of CNT distributions in the polymer matrix, volume fraction of CNT, edges boundary conditions and radial-to-thickness ratio on the bending and free vibration behavior of FG-CNTRC cylindrical are examined.
3
Zhan, Hang, Qiang Qiang Shi, Guang Wu et Jian Nong Wang. « A carbon nanotube approach for efficient thermally insulating material with high mechanical stability and fire-retardancy ». RSC Advances 10, no 37 (2020) : 21772–80. http://dx.doi.org/10.1039/d0ra03472j.
Texte intégral
4
Avramov, K. V., M. V. Chernobryvko et B. V. Uspensky. « Free vibrations of functionally gradient CNT-infused cylindrical shells ». Kosmìčna nauka ì tehnologìâ 25, no 2 (20 mai 2019) : 23–37. http://dx.doi.org/10.15407/knit2019.02.023.
Texte intégral
5
TEWARI, AARTI, et SURESH C. SHARMA. « Theoretical investigations on the effect of different plasmas on growth and field emission properties of a spherical carbon nanotube (CNT) tip placed over cylindrical surfaces ». Journal of Plasma Physics 79, no 5 (9 août 2013) : 939–48. http://dx.doi.org/10.1017/s0022377813000731.
Texte intégralRésumé :
AbstractThe theoretical investigations on the effect of different plasmas on the growth and field emission properties of a spherical carbon nanotube (CNT) tip placed over cylindrical CNT surfaces have been carried out for the typical glow discharge plasma parameters. Different plasmas such as H2, Ar, CH4 and CF4 have been considered, and the growth of the CNT in the presence of various plasmas has been estimated in the present investigation. This study suggests that the field emission from the CNT grown in the presence of the H2 plasma is largest. It is also found that amongst the plasmas considered, the CF4 plasma is the most favourable for the growth of the large radius CNT, since the radius achieved in the CF4 plasma is the largest.
6
Wei, Xianqi, Youzhang Zhu, Xianjun Xia, Xiaoli Wang, Weihuan Liu et Xin Li. « Carbon nanotube cathodes covered on the cylindrical surface of a fiber ». RSC Advances 5, no 22 (2015) : 17049–53. http://dx.doi.org/10.1039/c4ra14537b.
Texte intégral
7
Duong, Van Quang. « STATIC INVESTIGATION OF A FUNCTIONALLY GRADED CARBON NANOTUBES REINFORCED COMPOSITE CYLINDRICAL SHELL, DOUBLE-ENDED CLAMPED SUBJECTED TO EXTERNAL PRESSURE LOADS ». Journal of Science and Technique 17, no 5 (29 novembre 2022) : 28–46. http://dx.doi.org/10.56651/lqdtu.jst.v17.n05.528.
Texte intégralRésumé :
In this article, static analysis of clamped-clamped (C-C) functionally graded carbon nanotubes reinforced composite (FG-CNTRC) cylindrical shell subjected to external pressure was conducted. The governing equations were established by using higher-order shear deformation theory (HSDT) taking transverse normal stress effect into account. In this theory, the transverse displacement w is not a constant but rather is the second order polynomial of the coordinate along the thickness direction. Distribution of carbon nanotubes (CNT) across the shell thickness is assumed to be uniform (UD) or functionally graded in four types: FG-Ʌ, FG-V, FG-O, and FG-X. Effective material properties of FG-CNTRC cylindrical shells were estimated by the rule of mixture. An analytical solution using the simple trigonometric series and the Laplace transformation to solve governing equations of shell with clamped boundary condition at the both ends is presented. The validation of the applied approach was examined by comparing the results based on 3D exact model. The effects of the CNT distribution, the CNT volume fraction, and the geometrical parameters on the static behaviour of cylindrical shells subjected to external pressure were investigated. The result is remarkable that the stress components near the outer or inner surface vary most strongly, and in the case of a short or/and thick shell, the geometric parameter greatly affects the stress of shell.
8
Zhang, Jian, Jianping Wei, Detian Li, Huzhong Zhang, Yongjun Wang et Xiaobing Zhang. « A Cylindrical Triode Ultrahigh Vacuum Ionization Gauge with a Carbon Nanotube Cathode ». Nanomaterials 11, no 7 (22 juin 2021) : 1636. http://dx.doi.org/10.3390/nano11071636.
Texte intégralRésumé :
In this study, a cylindrical triode ultrahigh vacuum ionization gauge with a screen-printed carbon nanotube (CNT) electron source was developed, and its metrological performance in different gases was systematically investigated using an ultrahigh vacuum system. The resulting ionization gauge with a CNT cathode responded linearly to nitrogen, argon, and air pressures in the range from ~4.0 ± 1.0 × 10−7 to 6 × 10−4 Pa, which is the first reported CNT emitter-based ionization gauge whose lower limit of pressure measurement is lower than its hot cathode counterpart. In addition, the sensitivities of this novel gauge were ~0.05 Pa−1 for nitrogen, ~0.06 Pa−1 for argon, and ~0.04 Pa−1 for air, respectively. The trend of sensitivity with anode voltage, obtained by the experimental method, was roughly consistent with that gained through theoretical simulation. The advantages of the present sensor (including low power consumption for electron emissions, invisible to infrared light radiation and thermal radiation, high stability, etc.) mean that it has potential applications in space exploration.
9
Zhang, Z. H., N. Yu et W. H. Chao. « Estimating the Thermal Conductivities and Elastic Stiffness of Carbon Nanotubes as a Function of Tube Geometry ». Journal of Nanomaterials 2012 (2012) : 1–8. http://dx.doi.org/10.1155/2012/939806.
Texte intégralRésumé :
The thermal conductivities and elastic properties of carbon nanotubes (CNTs) are estimated by using the double-inclusion model, which is based on rigorous elasticity approach. The model regards a CNT as one inclusion (the inner cylindrical void) embedded in the other (the outer coaxial single-crystal graphite shell). The concept of homogenization is employed, and vital microstructural parameters, such as CNT diameter, length, and aspect ratio, are included in the present model. The relationship between microstructure and thermal conductivities and elastic stiffness of CNTs is quantitatively characterized. Our analytical results, benchmarked by experimental data, show that the thermal conductivities and elastic stiffness of CNTs are strongly dependent on the diameter of CNT with little dependence on the length of CNT.
10
Bayat, M. R., M. Mosavi Mashhadi et O. Rahmani. « Low-velocity impact response of sandwich cylindrical panels with nanotube-reinforced and metal face sheet in thermal environment ». Aeronautical Journal 122, no 1258 (18 septembre 2018) : 1943–66. http://dx.doi.org/10.1017/aer.2018.104.
Texte intégralRésumé :
ABSTRACTEmploying an analytical method, non-linear low-velocity impact response of carbon nanotube (CNT)-reinforced sandwich cylindrical panels in thermal environments is analysed. Two types of core (i.e. homogenous and functionally graded) are considered for sandwich panels. The face sheets of sandwich panels are multi-layer which consist of CNT-reinforced composite (CNTRC) and metal layers. Micromechanical models are used to estimate the material properties of CNTRCs. A higher-order shear deformation theory with a von Kármán-type of kinematic non-linearity provides the equations of motion. Temperature-dependent material properties are used to include the thermal effects. The equations of motion are solved using a two-step perturbation technique. Existing numerical results in the literature are used to validate the present method. The effect of nanotube volume fraction, material property gradient, impactor initial velocity, geometrical parameters of cylindrical panel, temperature change and edge boundary condition on the impact response of cylindrical panel structures is discussed. The quantitative results and analytical formulations can be helpful in better designing of CNTRC structures subjected to low-velocity impact in thermal environments.
Thèses sur le sujet "CYLINDRICAL CNT"
1
Thomas, David Andrew. « An adaptive control system for precision cylindrical grinding ». Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243279.
Texte intégral
2
Leden, Pavel. « Výroba tělesa pro klíčový zámek ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229935.
Texte intégralRésumé :
The diploma thesis is focused on the production of body for cylinder locks. This is production of very small and accurate parts. In the first part there is described the function of the lock, the sort of cylinder locks, their components and the basic types of safety elements. The second part is focused on the production of given type of body. The thesis deals with either existing production technology or proposals of possible innovation. This firstly consists in new organization of manufacturing operations. At the close we can find comparison of existing technology and new proposal.
3
UPADHYAY, NEHA. « ROLE OF HETEROATOMS ON CYLINDRICAL CNT SURFACE WITH HEMISPHERICAL TIP ». Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/15150.
Texte intégralRésumé :
This project puts forward a theoretical model to examine the growth of the carbon
nanotube (CNT) on top of catalyst substrate surface subjected to reactive plasma. Various
processes have been considered in this model, such as the charging rate of the CNT, kinetics of
electron, ions and neutral atoms. Also, the growth of the CNT due to diffusion and accumulation
of ions on the catalyst nanoparticles is taken into account. For characteristic glow discharge
plasma, numerical calculation on the impact of ion density, temperature and the substrate bias
over the growth rate of carbon nanotubes has been carried out. Through it, the change in radius,
height and the number density of hydrocarbon ions with time has been shown. Comparison has
been made between the two doped gases that are nitrogen and boron, and also with the undoped
condition. Along with it, the change in the concentration of the hydrocarbon ions in plasma along
the time is computed for three conditions (undoped, nitrogen doped and boron doped). The CNT
considered here has hemi-spherical tip as it provides better field emission which distinguish this
work from the work of Tewari and Sharma [31]. Different gases have been used in the process.
The mixture of gases includes hydrocarbon (CH3), hydrogen (H2), nitrogen (N2) and boron (B). It
is obtained that the height of CNT increments with the number density of carbon ions and radius
of CNT reduces with hydrogen ion density. The nitrogen and boron acts as doping elements here.
It is found that nitrogen obstruct both the height as well as radius of CNT, whereas in boron, both
the radius and height increases in comparison to the nitrogen doping. The present work can serve
to the better comprehension of procedure parameters amid growth of hemispherical tip CNT
with cylindrical surface by a Plasma Enhanced Chemical Vapor Deposition (PECVD) method.
4
Hong, Li-Fen, et 洪麗棻. « Fatigue Analysis and Optimization Design ofThe CNC Cylindrical Grinder Universal Series ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/4tpz53.
Texte intégralRésumé :
碩士國立虎尾科技大學
機械設計工程研究所
102
The purpose of this study is to lower deviation of workpiece by meeting high stability and rigidity to prevent the resonance in producing procedure of the CNC universal cylindrical grinding machine. Using finite element analysis software ABAQUS grinder machine tools for numerical simulation of several analysis for the following 1. Structural rigidity analysis, machine in external grinding load, the stress caused by the distribution and the deformation of the size of the whole structure. 2. Optimized design, the results of the analysis of components is corrected by setting the parameter to identify the best distribution of the material under the conditions comply with the limits, the structure to remove excess material to reduce costs and optimize the results before and after each comparison. 3. Vibration frequency analysis, analysis natural frequencies of grinder machine to avoid resonance. 4. Fatigue damage analysis, we aim on state of the transmission of outer diameter spindle to proceed in stress and fatigue life analysis by FE-SAFE Subroutine. In experiment section. We expect to obtain measured value of natural frequency. First, capturing the value of frequency response function by accelerometer with percussion hammer, and sending value which captured from hammer to spectrum analyzer for data processing. Finally, we import data to modal analysis software (ME’s scope)for establish a modal shape. The study result appears as following, max value of equivalent stress and average amount of displacement in Structural rigidity analysis are 0.67(mpa) and 0.92(μm). Base on the Hooke''s law of elasticity we can calculate static structural rigidity of machine is 63.3 (MNm-1). The result is less than equivalent stress yield stress of material FC300 300 (Mpa), so we can find out this grinder machine’s structure will not produce permanent deformation of inference in grinding processing. Optimal design optimization by comparing before and after, effectively reduce stress extreme value, the largest decline of about 5.43%. And modal analysis compared with the experimental, the average error percentage was less than 10% of parts. The whole structure percentage error does not exceed 3%, shows the results of analysis and practical percussion data Conformance with nice, has its reference value in the structural design phase. Finally, the outer diameter of the drive shaft in the dynamic analysis results, maximum stress is 231.3 (Mpa) less than S45C material yield strength 250 (Mpa), therefore, no distortion. The fatigue life of approximately 1,193,988 times, estimates into real life can use more than sixty years, from the viewpoint of structural strength, spindle has a good high breaking strength is designed to be safe.
5
Hung, Chung-Chi, et 洪宗淇. « Development of an In-process Multi-Measurement System for CNC Cylindrical Grinding Machines ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/91337124836315710614.
Texte intégralRésumé :
碩士國立彰化師範大學
電機工程學系
99
The in-process measurement system of present CNC cylindrical grinding machine can only measure workpiece with single dimension. It requires more than one set of single stage in-process measurement system to measure different dimensions of workpiece, and the measuring dimension need to be manually adjusted and calibrated. The process is not qualified for the requirement of flexible production. Therefore, the study aims to develop an in-process multi-measurement system for cylindrical grinding machines by applying servo drives to change the dimension automatically. There is only one set of multi-measurement system required to control more than one dimension on the workpiece diameter without manual adjustments. The resolution of measurement element proposed in this study is 0.1 μm and three measuring diameters are tested through servo drives to access 50 measurement results. The accuracy in changing measuring diameter reaches ±2.0 μm, which conforms to the ISO 230-2 international standard. Moreover, one set of multi-measurement system not only replaces 6 sets of single stage in-process measurement system but also reduces 50 % of material expenses, thereby saves 14.96 workdays of reset operation time per year and enhances grinding productivity.
6
Chatterjee, Saikat. « Performance Characterization Of A Cylindrical Ion Trap Mass Spectrometer ». Thesis, 2009. https://etd.iisc.ac.in/handle/2005/1038.
Texte intégralRésumé :
The cylindrical ion trap (CIT) is made up of two planar endcap electrodes and a cylindrical ring electrode. The investigation of simpler geometries like CIT has been started off in recent years with a view towards miniaturization. As a step towards this, numerical studies on CITs were carried out in our laboratory. Here in this study, our motive is to characterize a CIT through experiments. We have designed a mass spectrometer where a CIT is used as the mass analyzer. The trap performance was observed by varying six parameters associated with our experiment. The parameters are (1) the ionization voltage, (2) the ramp time, (3) the ionization time, (4) the cooling time, (5) the dead time and (6) the bias voltage applied across the filaments. All the experiments have been performed in the mass selective boundary ejection mode.
7
Chatterjee, Saikat. « Performance Characterization Of A Cylindrical Ion Trap Mass Spectrometer ». Thesis, 2009. http://hdl.handle.net/2005/1038.
Texte intégralRésumé :
The cylindrical ion trap (CIT) is made up of two planar endcap electrodes and a cylindrical ring electrode. The investigation of simpler geometries like CIT has been started off in recent years with a view towards miniaturization. As a step towards this, numerical studies on CITs were carried out in our laboratory. Here in this study, our motive is to characterize a CIT through experiments. We have designed a mass spectrometer where a CIT is used as the mass analyzer. The trap performance was observed by varying six parameters associated with our experiment. The parameters are (1) the ionization voltage, (2) the ramp time, (3) the ionization time, (4) the cooling time, (5) the dead time and (6) the bias voltage applied across the filaments. All the experiments have been performed in the mass selective boundary ejection mode.
8
« Stability analysis of laminated composite cylindrical shells and panelsstability analysis of laminated composite cylindrical shells and panels ». Tese, MAXWELL, 1997. http://www.maxwell.lambda.ele.puc-rio.br/cgi-bin/db2www/PRG_0991.D2W/SHOW?Cont=1946:pt&Mat=&Sys=&Nr=&Fun=&CdLinPrg=pt.
Texte intégral
9
Sonalikar, Hrishikesh Shashikant. « Numerical Investigation of Segmented Electrode Designs for the Cylindrical Ion Trap and the Orbitrap Mass Analyzers ». Thesis, 2016. http://etd.iisc.ac.in/handle/2005/3075.
Texte intégralRésumé :
This thesis is a numerical study of fields within ion traps having segmented electrodes1. The focus is on two cylindrical ion trap structures, two Orbit rap structures and one planar structure which mimics the field of the Orbit rap. In all these geometries, the segments which comprise the electrodes are easily Machin able rings and plates. By applying suitable potential to the different segments, the fields within these geometries are made to mimic the fields in the respective ideal structures.
This thesis is divided into 6 chapters.
Chapter 1 presents introduction and background information relevant to this work. A brief description of the Quadrupole Ion Trap (QIT) and the Orbit rap is given. The role of numerical simulations in the design of an ion trap geometry is briefly outlined. The motivation of this thesis is presented. The chapter ends by describing the scope of the thesis.
Chapter 2 presents a general description of computational methods used throughout this work. The Boundary Element Methods (BEM) is first described. Both 2D and 3D BEM are used in this work. The software for 3D BEM is newly developed and hence 3D BEM is described in more detail. A verification of 3D BEM is presented with a few examples. The Runge-Kutta method used to compute the trajectory of ion is presented. A brief overview of the Nelder-Mead method of function minimization is given. The computational techniques specifically used to obtain the results in Chapter 3, 4 and 5 are presented in the respective chapters.
Chapter 3 presents segmented electrode geometries of the Cylindrical Ion Trap (CIT). In these geometries, the electrodes of the CIT are split into number of mini-electrodes and different voltages are applied to these segmented electrodes to achieve the desired field. Two geometries of the segmented electrode CIT will be investigated. In the first, we retain the flat end cap electrodes of the CIT but split the ring electrode into five mini-rings. In the second configuration, we split the ring electrode of the CIT into three mini-rings and
1The term ‘segmented electrode’ used in this thesis has the same connotation as the term ‘split-electrode’ used in Sonalikar and Mohanty (2013). also divide the end caps into two mini-discs. By applying different potentials to the mini-rings and mini-discs of these geometries we will show that the field within the trap can be optimized to desired values. Two different types of fields will be targeted. In the first, potentials are adjusted to obtain a linear electric field and, in the second, a controlled higher order even multipole field are obtained by adjusting the potential. It will be shown that the different potentials to the segmented electrodes can be derived from a single RF generator by connecting appropriate capacitor terminations to segmented electrodes. The field within the trap can be modified by changing the value of the external capacitors.
Chapter 4 presents segmented electrode geometries which are possible alternatives for the Orbitrap. Two segmented-electrode structures, ORB1 and ORB2, to mimic the electric field of the Orbitrap, will be investigated. In the ORB1, the inner spindle-like electrode and the outer barrel-like electrode of the Orbitrap are replaced by rings and discs of fixed radii, respectively. In this structure two segmented end cap electrodes are added. In this geometry, different potentials are applied to the different electrodes keeping top-bottom symmetry intact. In the second geometry, ORB2, the inner and outer electrodes of the Orbitrap are replaced by an approximate step structure which follows the profile of the Orbitrap electrodes. For the purpose of comparing the performance of ORB1 and ORB2 with that of the Orbitrap, the following studies will be undertaken:
(1) variation of electric potential, (2) computation of ion trajectories, (3) measurement of image currents. These studies will be carried out using both 2D and 3D Boundary Element Method (BEM), the 3D BEM is developed specifically for this study. It will be seen in these investigations that ORB1 and ORB2 have performance similar to that of the Orbitrap, with the performance of the ORB1 being seen to be marginally superior to that of the ORB2. It will be shown that with proper optimization, geometries containing far fewer electrodes can be used as mass analysers. A novel technique of optimization of the electric field is proposed with the objective of minimizing the dependence of axial frequency of ion motion on the initial position of an ion. The results on the optimization of 9 and 15 segmented-electrode trap having the same design as ORB1 show that it can provide accurate mass analysis.
Chapter 5 presents a segmented electrode planar geometry named as PORB used to mimic the electric field of the Orbit rap. This geometry has two planes, each plane consisting of 30 concentric ring electrodes. Although the geometry of PORB does not have conventional inner and outer electrodes of the Orbit rap, it will be shown that by selecting appropriate geometry parameters and suitable potentials for the ring electrodes, this geometry can trap the ions into an orbital motion similar to that in the Orbit rap. The performance of the planar geometry is studied by comparing the variation of potential, ion trajectories and image current in this geometry with that in the Orbit rap. The optimization of applied potentials is performed to correct the errors in the electric field so that the variation of axial frequency of ions with their initial position is minimized.
Chapter 6 presents the summary and a few concluding remarks
10
Sonalikar, Hrishikesh Shashikant. « Numerical Investigation of Segmented Electrode Designs for the Cylindrical Ion Trap and the Orbitrap Mass Analyzers ». Thesis, 2016. http://hdl.handle.net/2005/3075.
Texte intégralRésumé :
This thesis is a numerical study of fields within ion traps having segmented electrodes1. The focus is on two cylindrical ion trap structures, two Orbit rap structures and one planar structure which mimics the field of the Orbit rap. In all these geometries, the segments which comprise the electrodes are easily Machin able rings and plates. By applying suitable potential to the different segments, the fields within these geometries are made to mimic the fields in the respective ideal structures.
This thesis is divided into 6 chapters.
Chapter 1 presents introduction and background information relevant to this work. A brief description of the Quadrupole Ion Trap (QIT) and the Orbit rap is given. The role of numerical simulations in the design of an ion trap geometry is briefly outlined. The motivation of this thesis is presented. The chapter ends by describing the scope of the thesis.
Chapter 2 presents a general description of computational methods used throughout this work. The Boundary Element Methods (BEM) is first described. Both 2D and 3D BEM are used in this work. The software for 3D BEM is newly developed and hence 3D BEM is described in more detail. A verification of 3D BEM is presented with a few examples. The Runge-Kutta method used to compute the trajectory of ion is presented. A brief overview of the Nelder-Mead method of function minimization is given. The computational techniques specifically used to obtain the results in Chapter 3, 4 and 5 are presented in the respective chapters.
Chapter 3 presents segmented electrode geometries of the Cylindrical Ion Trap (CIT). In these geometries, the electrodes of the CIT are split into number of mini-electrodes and different voltages are applied to these segmented electrodes to achieve the desired field. Two geometries of the segmented electrode CIT will be investigated. In the first, we retain the flat end cap electrodes of the CIT but split the ring electrode into five mini-rings. In the second configuration, we split the ring electrode of the CIT into three mini-rings and
1The term ‘segmented electrode’ used in this thesis has the same connotation as the term ‘split-electrode’ used in Sonalikar and Mohanty (2013). also divide the end caps into two mini-discs. By applying different potentials to the mini-rings and mini-discs of these geometries we will show that the field within the trap can be optimized to desired values. Two different types of fields will be targeted. In the first, potentials are adjusted to obtain a linear electric field and, in the second, a controlled higher order even multipole field are obtained by adjusting the potential. It will be shown that the different potentials to the segmented electrodes can be derived from a single RF generator by connecting appropriate capacitor terminations to segmented electrodes. The field within the trap can be modified by changing the value of the external capacitors.
Chapter 4 presents segmented electrode geometries which are possible alternatives for the Orbitrap. Two segmented-electrode structures, ORB1 and ORB2, to mimic the electric field of the Orbitrap, will be investigated. In the ORB1, the inner spindle-like electrode and the outer barrel-like electrode of the Orbitrap are replaced by rings and discs of fixed radii, respectively. In this structure two segmented end cap electrodes are added. In this geometry, different potentials are applied to the different electrodes keeping top-bottom symmetry intact. In the second geometry, ORB2, the inner and outer electrodes of the Orbitrap are replaced by an approximate step structure which follows the profile of the Orbitrap electrodes. For the purpose of comparing the performance of ORB1 and ORB2 with that of the Orbitrap, the following studies will be undertaken:
(1) variation of electric potential, (2) computation of ion trajectories, (3) measurement of image currents. These studies will be carried out using both 2D and 3D Boundary Element Method (BEM), the 3D BEM is developed specifically for this study. It will be seen in these investigations that ORB1 and ORB2 have performance similar to that of the Orbitrap, with the performance of the ORB1 being seen to be marginally superior to that of the ORB2. It will be shown that with proper optimization, geometries containing far fewer electrodes can be used as mass analysers. A novel technique of optimization of the electric field is proposed with the objective of minimizing the dependence of axial frequency of ion motion on the initial position of an ion. The results on the optimization of 9 and 15 segmented-electrode trap having the same design as ORB1 show that it can provide accurate mass analysis.
Chapter 5 presents a segmented electrode planar geometry named as PORB used to mimic the electric field of the Orbit rap. This geometry has two planes, each plane consisting of 30 concentric ring electrodes. Although the geometry of PORB does not have conventional inner and outer electrodes of the Orbit rap, it will be shown that by selecting appropriate geometry parameters and suitable potentials for the ring electrodes, this geometry can trap the ions into an orbital motion similar to that in the Orbit rap. The performance of the planar geometry is studied by comparing the variation of potential, ion trajectories and image current in this geometry with that in the Orbit rap. The optimization of applied potentials is performed to correct the errors in the electric field so that the variation of axial frequency of ions with their initial position is minimized.
Chapter 6 presents the summary and a few concluding remarks
Chapitres de livres sur le sujet "CYLINDRICAL CNT"
1
Korbi, Anis, Mehdi Tlija, Borhen Louhichi et Abdelmajid BenAmara. « A Computer Aided Tolerancing (CAT) Tool of Non-rigid Cylindrical Parts Assemblies ». Dans Lecture Notes in Mechanical Engineering, 23–32. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-27146-6_3.
Texte intégral
2
Nakao, Y., et E. Urata. « Study on a CNC Free form Surface Machining System with a Rotating Cylindrical Tool ». Dans Proceedings of the Thirty-First International Matador Conference, 603–8. London : Macmillan Education UK, 1995. http://dx.doi.org/10.1007/978-1-349-13796-1_90.
Texte intégral
3
Pawade, Raju, Nikhil Khatekar, Sameer Ghanvat et Nitesh Gothe. « Machining Performance Evaluation of Titanium Biomaterial, Ti6Al4V in CNC cylindrical turning Using CBN Insert ». Dans Advances in Sustainable Machining and Manufacturing Processes, 225–48. Boca Raton : CRC Press, 2022. http://dx.doi.org/10.1201/9781003284574-15.
Texte intégral
4
Bui, Ngoc Tuyen, et Trong Nghia Hoang. « Study on Selecting the Appropriate Process Parameters When CNC Cylindrical Grinding Heat-Treated Alloy Steel ». Dans Lecture Notes in Mechanical Engineering, 427–36. Cham : Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-31824-5_51.
Texte intégral
5
Ansari, Shabana Yasmeen, Shoaib Anwar Ansari, Farhan Alshammari et Sirajudheen Anwar. « CNT-Based Nano Medicine From Synthesis to Therapeutic Application ». Dans Innovative Approaches for Nanobiotechnology in Healthcare Systems, 175–211. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-8251-0.ch006.
Texte intégralRésumé :
Carbon nanotubes (CNTs) are allotropes of carbon consisting of cylindrical tubes, made up of graphite with a diameter of several nm to a length of several mm. They had extraordinary structural, mechanical, and electronic properties due to their small size and mass, high mechanical resilience, and high electrical and thermal conductivity. Their large surface area made them applicable in pharmacy and medicine and adsorb or conjugate a broad variety of medical and diagnostic agents (drugs, genes, vaccines, antibodies, biosensors, etc.). They are often used to deliver drugs directly into the cells without going through the metabolic process of body. In addition to drug delivery and gene therapy, CNTs are also used for tissue regeneration, diagnostic biosensors, chiral drug enantiomer separation, drug extraction, and drug or pollutant analysis. CNTs have recently been discovered as effective antioxidants. The ADME and toxicity of different types of CNTs have also been documented here, as well as the prospects, advantages, and challenges of this promising bio-nano technology.
6
Mondal, Sibabrata, et Dipankar Bose. « Evaluation of Surface Roughness in Wire Electrical Discharge Turning Process ». Dans Machine Learning Applications in Non-Conventional Machining Processes, 114–36. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-3624-7.ch008.
Texte intégralRésumé :
This investigation presents an experimental investigation in developing small cylindrical pins in electrolytic tough pitch copper (ETP Cu) material using wire electrical discharge turning (WEDT) to evaluate surface roughness of the cylindrical turning faces. The material ETP Cu is soft in nature and has growing range of application in the field of aerospace and electronics industries for advanced applications. In this process, a customized rotary spindle has been developed and added to five-axis CNC wire electrical discharge machine (WEDM) and straight turning of the cylindrical pin has been done up to a length of 15mm with 0.5mm diameter. Under this investigation, 31 experiments along with two confirmation tests have been carried out to study the influence of four design factors—pulse on time, pulse off time, spindle speed, and servo voltage—on the machining performance of surface roughness by means the technique of design of experiment (DOE).
7
Ikram, Muhammad, Ali Raza, Atif Shahbaz, Haleema Ijaz, Sarfraz Ali, Ali Haider, Muhammad Tayyab Hussain, Junaid Haider, Arslan Ahmed Rafi et Salamat Ali. « Carbon Nanotubes ». Dans Sol Gel and other Fabrication Methods of Advanced Carbon Materials [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.95442.
Texte intégralRésumé :
Carbon nanotubes (CNTs) are referred to as carbon nano-architecture allotropes, with wrapped graphene sheets forming a cylindrical structure. CNTs are either developed by metals or narrow-band semiconductors with rolling graphene sheets in various ways. Researchers have dedicated a great deal of attention to understanding the fascinating properties of CNTs over the years, and possess certain peculiar properties, such as a high degree of stiffness, a wide ratio of length to diameter, and remarkable toughness, and are employed in a number of applications. These properties can be enhanced by scheming the diameter, nature of walls, chirality, length of CNTs which is rolled up, and depending on the synthesis process. This chapter extensively covers the various properties of CNTs and how it influences to desired applications and also explains numerous methods of synthesis and processing of CNTs with advantages and some drawbacks.
8
Gosselin, C., E. Fritz et L. Seiler. « CnC manufacturing of circular faced cylindrical gears ». Dans International Conference on Gears 2017, 1343–52. VDI Verlag, 2017. http://dx.doi.org/10.51202/9783181022948-1343.
Texte intégral
9
Allison, Penelope M. « Casa del Menandro Supplement ». Dans The Insula of the Menander at Pompeii. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780199263127.003.0024.
Texte intégralRésumé :
The descriptions and measurements in following entries have been translated directly from the inventories compiled by Antonio d’Ambrosio. D’Ambrosio carried out the organization of the finds that were reportedly removed from the Casa del Menandro between 1979 and 1981, and stored in the Casa di Bacco storerooms in Pompeii. These finds had been left in situ, presumably in this house, since its excavation in the 1930s. However, it is not absolutely certain that the artefacts now inventoried as being from the Casa del Menandro were actually all excavated from that house, particularly figurative pieces. Such artefacts are unlikely to have been left in the house and not inventoried at the time of excavation. Also precise provenances, within the house, have not been provided in these recent inventories. Some of these items can be identified as particular finds recorded in the excavation reports, and these have been included in the main catalogue for the Casa del Menandro. For others there are a number of possibilities which are included here and in the main catalogue. None of these artefacts have been studied in detail. Dimensions: 185 mm × 215 mm; d.: 41 mm. Description: fragment of white marble with part of an inscription in two lines (h. of letters: 38 mm): ‘MANTON / MAMI’. Present location: Pompeii Collection, GF (inv. no. 17594, locatable). Reference: Pomp. archive neg. 42120. Discussion: possibly cat. no. 765 or 920. Dimensions: h.: 140 mm; max. diam.: 158 mm. Fabric: yellowish-orange. Description: Cylindrical neck and part of an ovoid body of an amphora. Stamped. Present location: Pompeii Collection, CB (inv. no. 17595). Discussion: possibly cat. no. 275, 382, 401, 549, 551, 593, or 634. Dimensions: h.: 380 mm; diam. of rim: 113 mm. Fabric: orange. Description: fragments of an amphora of Dressel form 5. Present location: Pompeii Collection, GF (inv. no. 17596, locatable). Reference: Pomp. archive neg. D/82718. Discussion: possibly cat. no. 275, 382, 401, 549, 551, 593, or 634. Dimensions: h.: 152 mm; diam. of rim: 123 mm. Fabric: orange. Description: Fragment of an amphora with a large rounded rim, cylindrical neck, oblique shoulder, and double strap handle from the shoulder to the centre of the neck.
10
Allison, Penelope M. « Unit I 10,13 ». Dans The Insula of the Menander at Pompeii. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780199263127.003.0021.
Texte intégralRésumé :
Giornali degli Scavi: A,VI,7 (Apr. 1929–Dec. 1935): 175 (15 Apr. 1932); 201–3 (2–7 July 1932); 342–3 (12–13 June 1933). Elia 1934: 340–1. The recording of the excavation for this area is again fairly summary, but reporting the removal of the volcanic deposit below the fallen rafters. It was obviously left partially unexcavated for nearly a year. Present location: unknown, not inventoried at time of excavation. Description: Fragmentary amphora with a black painted inscription on the neck. Inscription:. Present location: unknown, not inventoried at time of excavation. Reference: inscription: Della Corte 1933: 318, no. 339. Discussion: see discussion on amphora. Dimensions: preserved l.: 140 mm. Description: Iron slide key with tapering stem of rectangular section (max. dimensions: 20 mm × 10 mm). Suspension ring (diam.: c.30 mm) and L-shaped bit, with the remains of two teeth. Present location: Pompeii Collection. CB (inv. no. 5057). Discussion: Similar type to cat. no. 136. See discussion on locks and keys. Description: small vase. Present location: unknown, not inventoried at time of excavation. Present location: unknown, not inventoried at time of excavation. Description: base of vase. Present location: unknown, not inventoried at time of excavation. Discussion: excavators recorded that this was found on cat. no. 1914. Dimensions: h.: 0.9 m (GdSc). Description: one amphora is cylindrical with an inscription in black. Present location: unknown, left in situ at time of excavation (inv. no. 5631). Discussion: see discussion on amphora. Present location: unknown, not inventoried at time of excavation. Discussion: see discussion on axes. Dimensions: h.: 248 mm; diam.: 159 mm. Description: Large funnel with a bell-shaped bowl, decorated with incised concentric lines at the carination and on the inside of the rim. Tapering cylindrical funnel, consisting of a folded piece of lamina, soldered to the base of the bowl. The end of the funnel is missing. Preserved brass colour inside rim suggests this was high-quality bronze. Present location: Pompeii Collection, CB (inv. no. 5055). Reference: Tassinari 1993: i.145, and ii.198, 402. Discussion: Tassinari suggested (1993: i.232) that such funnels were for table use. According to White (1975: 124), these were used to decant wine from amphorae into lagoenae.
Actes de conférences sur le sujet "CYLINDRICAL CNT"
1
D, Pratheesha, Sandhya M, Shravani P.L, P. Vimala et Nithin Kumar N. R. « Efficiency Analysis of Cylindrical CNT MOSFET ». Dans 2023 International Conference on Advances in Electronics, Communication, Computing and Intelligent Information Systems (ICAECIS). IEEE, 2023. http://dx.doi.org/10.1109/icaecis58353.2023.10170705.
Texte intégral
2
Witharana, Sanjeeva, Haisheng Cheng et Yulong Ding. « Enhanced Natural Convective Heat Transfer of CNT-Ethylene Glycol-Water Suspensions ». Dans ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52372.
Texte intégralRésumé :
This paper presents an experimental study on the rheology and steady state natural convective heat transfer of suspensions of Carbon nanotubes (CNT) in the Water - Ethylene Glycol (WEG) base liquid, heated in a cylindrical cavity. Two series of experiment were performed in two orientations of the central axis of the cavity; vertical, and, horizontal. In vertical axis experiments, the heat was supplied from the bottom. The cylindrical cavity was made out of Aluminium, 10mm in height and 240mm in diameter. The heat input was 215W/m2. The CNTs used had an aspect ratio of ∼150. There were six suspensions investigated in either series of tests; CNT 0.1wt%, and EG 0, 10, 25, 50, 75 & 100wt%. It was found that the vertical axis orientation deteriorates heat transfer in all cases. However for horizontal orientation, there is a spectacular enhancement of up to 83% depending upon the EG concentration. The results also show that WEG-CNT suspension demonstrates non-Newtonian behaviour, which augments with increasing EG concentration.
3
Volkov, Alexey N., Kiril R. Simov et Leonid V. Zhigilei. « Mesoscopic Model for Simulation of CNT-Based Materials ». Dans ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68021.
Texte intégralRésumé :
A mesoscopic computational model is developed for simulation of the collective behavior of carbon nanotubes (CNTs) in CNT-based materials. The model adopts a coarse-grained representation of a CNT as a sequence of stretchable cylindrical segments defined by a chain of nodes. The dynamic behavior of CNTs is governed by the equations of motion for the nodes, enabling computationally efficient “molecular dynamics-type” simulations. The internal part of the mesoscopic force field takes into account stretching and bending of individual CNTs. A novel computationally-efficient “tubular” potential method is developed for the description of van der Waals interactions among the nanotubes. The parameterization of the “tubular” potential is based on an interatomic potential for non-bonded interactions between carbon atoms. The application of the mesoscopic model to simulation of systems consisting of hundreds of CNTs demonstrates perfect energy conservation for times as long as tens of nanoseconds. Self-assembly of CNTs into bundles with hexagonal ordering of nanotubes is observed in simulations performed for systems with initial random orientation of CNTs.
4
Robison, Warren, Brian Jensen et Anton Bowden. « Patterned Carbon Nanotube Growth on Convex Cylindrical Stainless Steel Substrates for the Production of Coronary Stents ». Dans ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-60243.
Texte intégralRésumé :
This paper reports research in fabrication of cylindrical stents using carbon-infiltrated carbon nanotubes (CI-CNT), a material with good hemocompatibility. We demonstrate growth of CI-CNT forests in patterned lines on a 3 mm diameter stainless steel (SS) rod. Lines were patterned parallel, at 7°, at 45°, and perpendicular relative to the axis of the rod. Minimal cracking was seen in the parallel and angled lines. Significant cracking was seen in the perpendicular lines and we attempted to characterize the cracking in order to correlate it to width of the lines and height of the forest. No correlation was found but the average uncracked length was determined to be 414 μm with a standard deviation of 67 μm. We also demonstrate successful growth with minimal cracking of CI-CNT forests in a zig-zag type pattern in an effort to further the possibility of creating a coronary stent utilizing CI-CNT. Some of the patterned samples were also removed from the cylindrical substrate, resulting in free-standing, patterned, cylindrical patterns made from CI-CNT.
5
Nazarenko, Lidiia, Aleksandr Chirkov, Henryk Stolarski et Holm Altenbach. « Application of equivalent cylindrical inhomogeneity to modeling of CNT and analysis of influence of CNT distributions on response of functionally graded structural elements ». Dans The 13th international scientific conference “Modern Building Materials, Structures and Techniques”. Vilnius Gediminas Technical University, 2019. http://dx.doi.org/10.3846/mbmst.2019.081.
Texte intégralRésumé :
A mathematical model based on the concept of the energy-equivalent inhomogeneity combined with the method of conditional moments (MCM) has been applied to analyze Carbon Nanotube (CNT)-reinforced materials. The idea of the energy-equivalent inhomogeneity is to replace the inhomogeneity and its interphase by a single equivalent inhomogeneity. It is evaluated for cylindrical inhomogeneity with Gurtin-Murdoch surface model and spring layer model of interphases. Inclusion of multiple mechanisms in the description of interphases is applied to the CNT-reinforced materials. The CNT is modeled as a cylindrical high-stiffness surface. A weak zone surrounding the CNT can be modeled by a spring layer. In this case, one Gurtin-Murdoch and one spring layer models would need to be combined. To evaluate the effective properties of CNT-reinforced materials a statistical method, the MCM, has been employed which describes random distribution of CNT’s. Closed-form formulas for the components of the effective stiffness tensor of such composites have been developed. A composite plate weakened by a hole under different types of loading is considered. It is assumed, that the plate made of the polymer with randomly distributed and disoriented CNT’s. Analysis of how various special distributions of CNT concentration affect the response of this plate is performed.
6
Calderón-Colón, Xiomara, et Otto Zhou. « Development of Carbon Nanotube Field Emitters for X-Ray Source ». Dans ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-175998.
Texte intégralRésumé :
Carbon Nanotubes (CNTs) have been shown excellent field emission emitters due to their unique properties. CNTs are a stable form of carbon; a graphite sheet rolls up forming a cylindrical shape with high aspect ratio, low turn-on field, high current density, high strength (1) and can generate quality x-ray radiation (2). These properties make carbon nanotubes very attractive for field emission applications. Field emission cathodes are the central part of field emission displays (FED) and carbon nanotubes field emission x-ray source. FED is a new flat panel display technology; this technology enables much thinner, lighter, and highest resolution displays than the cathode ray tubes (CRT). CNTs field emission x-ray source technology has applications in medical imaging and homeland security (2–7). The current thermionic cathodes have several disadvantages over CNT based field emission x-ray source such as slow response time, high power consumption, high operation temperature that reduces the lifetime of the x-ray tube (4) and large device size (3). Also CNT based field emission x-ray source offers improvement in high temporal resolution and capabilities for spatial and temporal modulation (7). CNT field emission x-ray source technology is available in single- and multi-beam imaging system. Multi-beam imaging system offers image of an object from multiple projection angles without mechanical motion (7).
7
Herren, Blake, Mrinal C. Saha, M. Cengiz Altan et Yingtao Liu. « Effects of Rapid Microwave-Curing on Mechanical and Piezoresistive Sensing Properties of Elastomeric Nanocomposites ». Dans ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23175.
Texte intégralRésumé :
Abstract Carbon nanotubes (CNTs) have the unique ability to absorb microwave radiation and efficiently transfer the energy into substantial heat. When adequately dispersed in a thermoset polymer, such as polydimethylsiloxane (PDMS), the nanocomposite can be fully cured in seconds in a microwave oven rather than in hours in a convection oven. In this paper, cylindrical PDMS nanocomposites containing well-dispersed CNTs are fabricated by either microwave-curing or conventional thermal-curing. The mechanical, electrical, and piezoresistive properties of the fabricated samples are compared to understand the effects of different curing methods. Microwave-cured nanocomposites exhibit a significantly reduced compressive modulus for different CNT loadings. In addition, the electrical conductivity of microwave-cured nanocomposites is significantly enhanced over the thermally-cured counterparts. Experimental results demonstrate that the one-step microwave-curing procedure can improve the electrical conductivity of 1 wt% nanocomposites by almost 150 % over thermal-curing. However, their piezoresistive sensitivity remains remarkably similar, showing the potential for microwave-curing to replace thermal-curing for the manufacturing of highly flexible CNT-based nanocomposites.
8
Momeni, Kasra, et Aria Alasty. « Stress Distribution on Open-Ended Carbon Nanotubes ». Dans 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70251.
Texte intégralRésumé :
The stress distribution on open-ended Carbon Nanotubes (CNTs) embedded in a composite material is considered in this work and an analytical solution for the stress distribution has been obtained. The effects of CNT’s thickness and CNT’s length on the distribution of stress have been investigated. To find the governing relations, continuity equations of the axisymmetric problem in cylindrical coordinate (r,θ,z) are used. Under some assumptions, the governing equations are solved and by using constitutive equations and applying the boundary conditions, an equation which relates the stress applied to the representative volume element with the stress distribution on the CNT, has been found. The analytical solution has been applied to three different CNTs. The results for the open-ended CNTs have been compared with the results for closed-ended ones.
9
Chahine, Nadeen O., Nicole M. Collette, Heather Thompson et Gabriela G. Loots. « Application of Carbon Nanotubes in Cartilage Tissue Engineering ». Dans ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-192494.
Texte intégralRésumé :
Carbon nanotubes (CNTs) are cylindrical allotropes of carbon that are nanometers in diameter and posses unique physical properties, positioning them as ideal materials for studying physiology at a single cell level. CNTs have the potential to become a very important component of medical therapeutics, likely acting as (a) drug delivery system [1], (b) existing as an interfacial layer in surgical implants [2,3], or (c) acting as scaffolding in tissue engineering [4,8]. While some studies have explored the use of CNTs as a novel material in regenerative medicine, they have not yet been fully evaluated in cellular systems. One major limitation of CNTs that must be overcome is their inherent cytotoxicity. The goal of this study is to assess the long-term biocompatibility of CNTs for chondrocyte growth. We hypothesize that CNT-based material in tissue engineering can provide an improved molecular sized substrate for stimulation of cellular growth, and structural reinforcement of the scaffold mechanical properties. Here we present data on the effects of CNTs on chondrocyte viability and biochemical deposition examined in composite materials of hydrogels + CNTs mixtures. Also, the effects of CNTs surface functionalization with polyethlyne glycol (PEG) or carboxyl groups (COOH) were examined.
10
Arroyo, B., J. A. Álvarez, F. Gutiérrez-Solana, A. Cayón, S. Cicero, L. Andrea et R. Lacalle. « Estimation of the Threshold Toughness in Acid Environments (KIEAC) By Using Circumferential Notched Tensile Specimens (CNT) ». Dans ASME 2021 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/pvp2021-61761.
Texte intégralRésumé :
Abstract Medium and high-strength steels working in harsh environments are susceptible of suffering of mechanical properties loss due to hydrogen presence. In order to avoid catastrophic failures, the estimation of the fracture toughness in environment is necessary, but sometimes it is not convenient the use of standard tests; an alternative to the aforementioned traditional fracture mechanics specimens are Circumferential Notched Tensile specimens (CNT), which consist of cylindrical tensile specimens that incorporate a circumferential notch. In this work, CNT specimens subjected to acid aggressive environments, generated by cathodic polarization, are used to estimate the fracture toughness in environment, KIEAC. For this purpose, two methodologies, one proposed by Singh Raman et al. in the 2000’s and another by Cayón et al. in the 2010’s, are compared. Both formulations rely on similar classic fracture mechanics bases, differing mainly in the way to correct the effects of non-centering of the ligament, caused by asymmetries in the growth of annular cracks in CNT specimens. Both are finally validated to estimate KIEAC, showing good accuracy within the ±L15%.