Structural and Dynamical Properties of Intercalated Layered Silicates

1987 ◽  
Vol 111 ◽  
Author(s):  
W. Jin ◽  
S. D. Mahanti ◽  
S. A. Solin ◽  
H. C. Gupta
Keyword(s):  
Dynamic Properties ◽  
Practical Interest ◽  
Interlayer Spacing ◽  
Layered Silicates ◽  
Size Difference ◽  
Interior Space ◽  
Ionic Radii ◽  
Dynamical Properties ◽  
Transverse Rigidity ◽  
Silicate Layers

Structural and dynamical properties of intercalated solids in general [1], and layered silicates of the type AxB1−x -Vermiculite in particular, are of both fundamental and practical interest. In these systems, two types of ions A and B with different ionic radii occupy the space between two silicate layers. On the fundamental side, one is interested in studying the average interlayer spacing as a function of (1) the concentration x of the large ion, (2) sizes and compressibilities of the intercalated ions and (3) the transverse rigidity of the silicate layers. In addition, one is interested in the dynamic properties of these solids. On the practical side, when the size difference between the two intercalants is large, one obtains pillared clays which are characterized by widely spaced silicate layers that are propped apart by sparsely distributed larger interlayer cations (sometimes referred to as pillars) [2]. The enormous free volume of accessible interior space that is derived from such an open structure has significent practical application in the field of catalysis and sieving.

scholarly journals Investigations on Microstructural and Layer Disorder Parameters of Na-Montmorillonite-Glycine Intercalation Compounds

2012 ◽  
Vol 60 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Adnan Hossain Khan ◽  
Parimal Bala ◽  
AFM Mustafizur Rahman ◽  
Mohammad Nurnabi
Keyword(s):  
Crystallite Size ◽  
Chain Length ◽  
Line Profile ◽  
Profile Analysis ◽  
Interlayer Spacing ◽  
Line Profile Analysis ◽  
X Ray ◽  
Microstructural Parameters ◽  
Silicate Layers ◽  
Layer Disorder

Glycine-Montmorillonite (Gly-MMT) composite has been synthesized through intercalation process using Na-Montmorillonite (Na- MMT) and glycine ethylester hydrochloride. Gly-MMT was employed for the synthesis of dipeptide (Gly-Gly-MMT). Microstructural parameters such as crystallite size, r.m.s. strain (<e2>1/2) and layer disorder parameters such as variation of interlayer spacing (g) and proportion of planes affected by such defects (?) of the samples have been calculated by X-ray line profile analysis. In comparison to Na-MMT the basal spacings (d001) of Gly-MMT and Gly-Gly-MMT were reduced by 2.4Å and 1.8Å respectively. The value of d001 of Gly-Gly-MMT (13.3 Å) suggests the monolayer orientation of dipeptide into interlayer spaces. It is also suggested that more homogeneity in the stacking of silicate layers is attained in Gly-Gly-MMT due to the increased chain length of the dipeptide and orientation in monolayer style.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10331Dhaka Univ. J. Sci. 60(1): 25-29, 2012 (January)

Bistability and its regulation by serotonin in the endogenously bursting neuron R15 in Aplysia

1996 ◽  
Vol 75 (2) ◽  
pp. 957-962 ◽  
Author(s):  
H. A. Lechner ◽  
D. A. Baxter ◽  
J. W. Clark ◽  
J. H. Byrne
Keyword(s):  
Electrical Activity ◽  
Dynamic Properties ◽  
Computational Studies ◽  
Nonlinear Dynamical ◽  
Bursting Neuron ◽  
Current Pulses ◽  
Low Concentrations ◽  
Dynamical Properties ◽  
Mode Transitions ◽  
Model Support

1. Previous computational studies of models of neuron R15 in Aplysia have indicated that several distinct modes of electrical activity may coexist at a given set of parameters, that this multistability can be modulated by transmitters such as serotonin (5-HT) and that brief perturbations of the membrane potential can induce persistent changes in the mode of electrical activity. To test these predictions, the responses of R15 neurons to injections of brief (1.5 s) current pulses were recorded intracellularly in the absence and presence of 5-HT. 2. In the absence of 5-HT, brief perturbations induced abrupt transitions in the electrical activity from bursting to beating. Such transitions were observed in approximately 20% of the cases. The duration of beating activity varied from several seconds to tens of minutes. In the presence of low concentrations (1 microM) of 5-HT, both the probability of mode transitions and the duration of induced beating activity increased significantly. 3. These results indicate that at least two stable modes of electrical activity can coexist in R15 neurons and that this bistability can be regulated by 5-HT. In general, these conclusions agree with the results from analyses of mathematical models of R15. Although the function of these dynamic properties in R15 is speculative, our results, interpreted on the background of the model, support the notion that nonlinear dynamical properties of individual neurons can endow them with richer forms of information processing than has generally been appreciated.

scholarly journals The Stability of Intercalated Sericite by Cetyl Trimethylammonium Ion under Different Conditions and the Preparation of Sericite/Polymer Nanocomposites

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 900 ◽  
Author(s):  
Yu Liang ◽  
Dexin Yang ◽  
Tao Yang ◽  
Ning Liang ◽  
Hao Ding
Keyword(s):  
Aspect Ratio ◽  
Polymer Nanocomposites ◽  
Interlayer Space ◽  
Chemical Resistance ◽  
Interlayer Spacing ◽  
Layered Silicates ◽  
Pure Epoxy ◽  
Different Temperatures ◽  
The Stability ◽  
Ultraviolet Shielding

Layered silicates are suitable for use as fillers in nanocomposites based on their particular features, such as large aspect ratio, easy availability, and chemical resistance. Among them, sericite is distinguished for its higher aspect ratio, higher resilience, and ultraviolet shielding and absorption. Previously, sericite was structure-modified and intercalated by CTAB to expand its interlayer space. The intercalated sericite seems promising for use in the fabrication of polymer/sericite composites or pillared sericite. However, special attention should be paid to the stability of the intercalated sericite because the CTAB inside the layer may be de-intercalated, which would affect the interlayer spacing and its surface properties. In this article, the stability of the sericite intercalated by CTAB was tested by changing different variables, such as different washing solvents, different temperatures, ultrasonic cleaning, and different solution conditions. Finally, sericite/polymer nanocomposites were produced with the stable intercalated sericite, and showed excellent properties compared with pure epoxy resin.

Influence of Epoxide Levels in Epoxidized Natural Rubber (ENR) Molecules on Cure Characteristics, Dynamic Properties and Mechanical Properties of ENR/Montmorillonite Clay Nanocomposites

2013 ◽  
Vol 844 ◽  
pp. 247-250
Author(s):  
Piriyapol Yokkhun ◽  
Bencha Thongnuanchan ◽  
Charoen Nakason
Keyword(s):  
Mechanical Properties ◽  
Dynamic Properties ◽  
Montmorillonite Clay ◽  
Layered Silicates ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Melt Mixing ◽  
Maximum Torque ◽  
Elongation At Break ◽  
Cure Characteristics

Nanocomposites based on epoxidized natural rubbers (ENRs) with various levels of epoxide groups (i.e., 10, 20, 30, 40 and 50 mol%) and organoclay were prepared by melt mixing process. The organoclay employed in this study was montmorillonite clay modified by octadecylamine (OC-MMT). Cure characteristics, dynamic properties and mechanical properties of ENRs nanocomposites filled with 5 phr of OC-MMT were studied. In all cases, X-ray diffraction results indicated intercalation of ENRs into the silicate interlayer as an increase in the interlayer distance of layered silicates was observed. The maximum torque and torque difference of ENRs nanocomposites increased with increasing levels of epoxide groups in ENRs. Additionally, it was also found that the tan δ value at Tg of the ENR-50 nanocomposite was much lower than those of other types of ENRs nanocomposite. This indicates stronger interaction between ENR-50 and OC-MMT. However, ENR-50 nanocomposite showed the poorest elasticity in term of the tan δ value at the ambient temperature compared to other types of ENRs nanocomposites. A good balance between strength and elasticity was also observed in the ENR-30 nanocomposite. These results are also consistent with the observation that tensile strength and elongation at break of ENR-30 nanocomposite were higher than those of other types of ENRs nanocomposites.

Effect of Carbon Black on Hysteresis of Rubber Vulcanizates: Equivalence of Surface Area and Loading

1976 ◽  
Vol 49 (4) ◽  
pp. 1076-1094 ◽  
Author(s):  
J. M. Caruthers ◽  
R. E. Cohen ◽  
A. I. Medalia
Keyword(s):  
Carbon Black ◽  
Surface Area ◽  
Functional Form ◽  
Volume Fraction ◽  
Dynamic Properties ◽  
Dynamic Test ◽  
Practical Interest ◽  
Interfacial Area ◽  
Experimental Conditions ◽  
Tan Δ

Abstract We have developed an empirical correlation between the loss tangent (tan δ) and the product of the volume fraction (ϕ) of carbon black in the composite and the total filler-polymer interfacial area per unit volume of composite (ψ). This correlation was applied to vulcanizates based on SBR-1500, SBR-1712, and NR with various compounding procedures and under different deformation conditions, including forced vibration nonresonant dynamic test machines, and the Goodyear-Healey pendulum rebound. The functional form of the correlation was qualitatively similar in all instances ; however, quantitative aspects of the correlation are dependent upon the particular experimental conditions. Tan δ is a weak function of the deformation amplitude over the region of practical interest. This is in contrast to hysteretic energy loss, which is proportional to the square of the amplitude. The validity of the correlation over wide ranges of amplitude, temperature, and frequency indicates that the viscoelastic relaxation or loss processes are similar over the range of conditions studied. Since the combined parameter, ϕψ, is proportional to ϕ2 multiplied by the specific surface area of the carbon black, this relation implies an equivalence between surface area and loading, with regard to tan 5. It has previously been shown that the elastic modulus depends on structure and loading. Thus, the dynamic properties, including hysteresis under various conditions, can be predicted from the carbon black properties, and compounds can be designed for desired dynamic properties by independent adjustment of loading, structure and surface area.

GLOBAL DYNAMIC PROPERTIES OF A SYNCHRONOUS MACHINE MODEL

2008 ◽  
Vol 18 (10) ◽  
pp. 3113-3128 ◽  
Author(s):  
PINGLI LU ◽  
YING YANG ◽  
LIN HUANG
Keyword(s):  
Dynamic Properties ◽  
Synchronous Machine ◽  
Chaotic Oscillations ◽  
Machine Model ◽  
Kyp Lemma ◽  
Global Dynamic ◽  
Asymptotic Stable ◽  
Static Feedback ◽  
Trivial Equilibrium ◽  
Dynamical Properties

In this paper, rich global dynamical properties are considered for a fundamental synchronous machine model: from global asymptotic stability of trivial equilibrium to chaotic oscillations. Based on Kalman–Yakubovich–Popov (KYP) lemma, static feedback controller is designed such that the synchronous machine model is global asymptotic stable which guarantees that the existence of limit cycles or chaotic oscillations is impossible.

Assessment of Dynamical Properties of Die Hammer MPM 10000 B Considering Deformations of Working Material

2008 ◽  
Vol 144 ◽  
pp. 71-76
Author(s):  
Ludwik Majewski ◽  
Arkadiusz Trąbka
Keyword(s):  
Numerical Simulations ◽  
Dynamic Properties ◽  
Graphical Form ◽  
Proper Selection ◽  
Low Level ◽  
Time Histories ◽  
Technical Specifications ◽  
Dynamical Properties ◽  
Selection Of ◽  
Calculation Models

This paper presents an assessment of dynamic properties of a die hammer. The object of research is the steam-air die hammer MPM 10000 B that is considered taking into account the deformations of the working material. Based upon the technical specifications, two calculation models of the hammer were developed assuring the proper selection of the parameters. Next, the numerical simulations were performed, which results were presented in a graphical form as time histories of displacements and accelerations of particular elements of the hammer. It was demonstrated that the analyzed design of a die hammer has sufficiently low level of vibration amplitudes as well as their accelerations.

scholarly journals Application of Organo-Magadiites for the Removal of Eosin Dye from Aqueous Solutions: Thermal Treatment and Regeneration

2018 ◽  
Author(s):  
Fethi Kooli ◽  
Yan Liu ◽  
Mustapha Abouddi ◽  
Souad Rakass ◽  
Hicham Oudghiri Hassani ◽  
...  
Keyword(s):  
Layered Silicate ◽  
Interlayer Spacing ◽  
Organic Cations ◽  
Basal Spacing ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Trans Conformation ◽  
Initial Concentration ◽  
Effective Removal ◽  
Silicate Layers

Na-magadiite exchanged with cetyl-trimethylammonium cations provided organophilic silicate materials that allowed the effective removal of the acidic dye "eosin". The organic cations were intercalated into the interlayer spacing of the layered silicate via an exchange reaction between the organic cations from their bromide salt and the solid Na-magadiite at room temperature. Different techniques were used to characterize the effect of the initial concentration of the surfactant on the structure of the organo-magadiites. The C, H, N analysis indicated that a maximum of organic cations of 1.03 mmol/g was achieved at initial concentrations higher than 0.25 mmol/g and was accompanied by an expansion of the basal spacing of 3.15 nm, with a tilted angle of 64.5&deg; to the silicate layers. The conformation of the organic surfactants was probed using solid-state 13C, finding mainly the trans conformation similar to that of the starting cetyl trimethylammonium bromide salt (C16TMABr). Thermal gravimetric analysis was carried out to study the thermal stability of the resulting organo-magadiites. The intercalated surfactants started to decompose at 200 &deg;C, with a mass loss percentage of 8 % to 25 %, depending on the initial loading of the surfactant, and was accompanied by a decrease of the basal spacing from 3.20 nm to 2.51 nm, as deduced from the in situ X-ray diffraction studies. At temperatures below 220 &deg;C, an expansion of the basal spacing from 3.15 to 3.35 nm occurred. These materials were used as a removal agent for the anionic dye "eosin". The maximum amount of the dye removed was related to the organic cation content and to the initial concentration of eosin, with an improvement from 2.5 mg/g to 98 mg/g. This value decreased when the organo-magadiite was preheated at temperatures above 200 &deg;C. The regeneration tests indicated that an 85 % removal efficiency was maintained after 6 cycles of use for the organo-magadiites.

scholarly journals Structural and Dynamic Properties of Hydrophobic Eutectic Solvents Based on Menthol and Fatty Acids: a Molecular Dynamics Simulation Study

2021 ◽  
Author(s):  
Samaneh Barani Pour ◽  
Jaber Jahanbin Sardroodi ◽  
Alireza Rastkar Ebrahimzadeh
Keyword(s):  
Molecular Dynamics ◽  
Fatty Acids ◽  
Dynamic Properties ◽  
Mean Square Displacement ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Eutectic Mixtures ◽  
Dynamical Properties ◽  
Reorientation Dynamics ◽  
Dynamics Simulations

Abstract The structural and dynamical properties of the binary mixture of Menthol (MEN) and Fatty acids (FAs) were investigated using molecular dynamics simulations. We focused on the relationship between the structural and dynamical properties of the eutectic mixtures of MEN and FAs with different molar percentages of FAs. Structural properties of the eutectic mixtures were characterized by calculating the combined distribution functions(CDFs), the radial distribution functions (RDFs), and the angular distribution functions (ADFs), and the Hydrogen bonding network between species and Spatial distribution functions (SDF). Further interaction between menthol and Caprylic acid molecules was confirmed by the results of these analyzes. Also, the transport properties of the mixtures were investigated by using the mean square displacement (MSD) of the centers of mass of the species, self-diffusion coefficients and vector reorientation dynamics (VRD) of bonds. The simulation results indicated that intermolecular interactions have a significant effect on the dynamic properties of species.

Regions of Reduced Dynamics in Dynamic Networks

2021 ◽  
Vol 31 (06) ◽  
pp. 2150080
Author(s):  
Roberto Galizia ◽  
Petri T. Piiroinen
Keyword(s):  
Parameter Space ◽  
Dynamic Properties ◽  
Dynamic Networks ◽  
Numerical Continuation ◽  
Continuation Methods ◽  
Simple Graphs ◽  
Asymptotic Dynamic ◽  
Dynamical Properties ◽  
Nonlinear Vector ◽  
Entire Network

We consider complex networks where the dynamics of each interacting agent is given by a nonlinear vector field and the connections between the agents are defined according to the topology of undirected simple graphs. The aim of the work is to explore whether the asymptotic dynamic behavior of the entire network can be fully determined from the knowledge of the dynamic properties of the underlying constituent agents. While the complexity that arises by connecting many nonlinear systems hinders us to analytically determine general solutions, we show that there are conditions under which the dynamical properties of the constituent agents are equivalent to the dynamical properties of the entire network. This feature, which depends on the nature and structure of both the agents and connections, leads us to define the concept of regions of reduced dynamics, which are subsets of the parameter space where the asymptotic solutions of a network behave equivalently to the limit sets of the constituent agents. On one hand, we discuss the existence of regions of reduced dynamics, which can be proven in the case of diffusive networks of identical agents with all-to-all topologies and conjectured for other topologies. On the other hand, using three examples, we show how to locate regions of reduced dynamics in parameter space. In simple cases, this can be done analytically through bifurcation analysis and in other cases we exploit numerical continuation methods.

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