scholarly journals Comparison of the Molecular Dynamics of C70 in the Solid and Liquid Phases

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
R. M. Hughes ◽  
P. Mutzenhardt ◽  
A. A. Rodriguez
Keyword(s):  
Molecular Dynamics ◽  
Solid State ◽  
Liquid Phase ◽  
Lower Energy ◽  
Solid Phase ◽  
Small Step ◽  
Correlation Times ◽  
Diffusion Constants ◽  
Liquid Phases ◽  
Two Phases

A previous study of C70 in deuterated benzenes generated evidence suggesting C70 exhibited unique reorientational behavior depending on its environment. We present a comparison of the dynamic behavior of this fullerene, in the solid and solution phases, to explore any unique features between these two phases. The effective correlation times, τCeff, of C70 in the solid state are 2 to 3 times longer than in solution. In the solid state, a noticeable decrease in all the carbons' correlation times is seen between 293 K to 303 K; suggesting a transition from isotropic to anisotropic reorientational behavior at this temperature change. Although C70 in solution experiences van der Waals type interactions, these interactions are not strong enough to slow the solution-state motion below what is observed in the solid state. All observed differences in the diffusion constants, DX and DZ, in solution are smaller than in the solid state suggesting a lower energy of activation between these two modes of reorientation in the liquid phase. A small-step diffusion “like” condition appears to be thermally generated in the solid phase at 323 K.

Molecular Dynamics Study of the Interfacial Thermal Conductance at the Graphene/Paraffin Interface in Solid and Liquid Phases

2013 ◽  
Author(s):  
Hasan Babaei ◽  
Pawel Keblinski ◽  
J. M. Khodadadi
Keyword(s):  
Molecular Dynamics ◽  
Solid Phase ◽  
Thermal Conductance ◽  
Md Simulations ◽  
Interfacial Thermal Conductance ◽  
A Value ◽  
Number Of Layers ◽  
Liquid Phases ◽  
Phase Systems ◽  
Parallel Configuration

By utilizing molecular dynamics (MD) simulations, we study the interfacial thermal conductance at the interface of graphene and paraffin. In doing so, we conduct non-equilibrium heat source and sink simulations on systems of parallel and perpendicular configurations in which the heat flow is parallel and perpendicular to the surface of graphene, respectively. For the perpendicular configuration, graphene with different number of layers are considered. The results show that the interfacial thermal conductance decreases with the number of layers and converges to a value which is equal to the obtained conductance by using the parallel configuration. We also study the conductance for the solid phase paraffin. The results indicate that solid paraffin-graphene interfaces have higher conductance values with respect to the corresponding liquid phase systems.

Multiphase Reactions and Reactors

2001 ◽  
Author(s):  
L. K. Doraiswamy
Keyword(s):  
Liquid Phase ◽  
Solid Phase ◽  
Complete Classification ◽  
Catalytic Reactions ◽  
Two Phase ◽  
Multiphase Reactions ◽  
Liquid Phases ◽  
Three Phase ◽  
Solid Form

The first three chapters of this part dealt with two-phase reactions. Although catalysts are not generally present in these systems, they can be used in dissolved form in the liquid phase. This, however, does not increase the number of phases. On the other hand, there are innumerable instances of gas-liquid reactions in which the catalyst is present in solid form. A popular example of this is the slurry reactor so extensively employed in reactions such as hydrogenation and oxidation. There are also situations where the solid is a reactant or where a phasetransfer catalyst is immobilized on a solid support that gives rise to a third phase. A broad classification of three-phase reactions and reactors is presented in Table 17.1 (not all of which are considered here). This is not a complete classification, but it includes most of the important (and potentially important) types of reactions and reactors. The thrust of this chapter is on reactions and reactors involving a gas phase, a liquid phase, and a solid phase which can be either a catalyst (but not a phasetransfer catalyst) or a reactant, with greater emphasis on the former. The book by Ramachandran and Chaudhari (1983) on three-phase catalytic reactions is particularly valuable. Other books and reviews include those of Shah (1979), Chaudhari and Ramachandran (1980), Villermaux (1981), Shah et al. (1982), Hofmann (1983), Crine and L’Homme (1983), Doraiswamy and Sharma (1984), Tarmy et al. (1984), Shah and Deckwer (1985), Chaudhari and Shah (1986), Kohler (1986), Chaudhari et al. (1986), Hanika and Stanek (1986), Joshi et al. (1988), Concordia (1990), Mills et al. (1992), Beenackers and Van Swaaij (1993), and Mills and Chaudhari (1997). Doraiswamy and Sharma (1984) also present a discussion of gas-liquid-solid noncatalytic reactions in which the solid is a reactant. In Chapter 7 we saw how Langmuir-Hinshelwood-Hougen-Watson (LHHW) models are normally used to describe the kinetics of gas-solid (catalytic) or liquid-solid (catalytic) reactions, and in Chapters 14 to 16 we saw how mass transfer between gas and liquid phases can significantly alter the rates and regimes of these two-phase reactions.

scholarly journals Tiny Bubbles

2009 ◽  
Vol 17 (1) ◽  
pp. 3-5
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Lower Energy ◽  
Critical Role ◽  
Interfacial Area ◽  
Consumer Products ◽  
Phase System ◽  
Two Phase ◽  
Liquid Phases ◽  
Phase Systems ◽  
Two Phases

This is not an article about the song made famous by the late (great) Don Ho. This is about a breakthrough in the understanding of how micrometer-sized bubbles can be stabilized for long periods of time. This can influence the taste, smell, and consistency of consumer products including food and cosmetics.In two-phase systems, which can include air (as bubbles) suspended within a liquid, the structures of the dispersed (bubbles) and continuous (liquid) phases play a critical role in determining the properties of the material. There is also the function of time in that the microstructure of the dispersed phase continuously evolves toward a state of lower energy by minimizing the surface area between the two phases (referred to as the interfacial area). In the long term, this time evolution diminishes the usefulness of two-phase systems. Emilie Dressaire, Rodney Bee, David Bell, Alex Lips, and Howard Stone have devised a way to stabilize a two-phase system for time periods of a year or longer.

scholarly journals Digesta transit in different segments of the gastrointestinal tract of pigs as affected by insoluble fibre supplied by wheat bran

2007 ◽  
Vol 98 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Aurélie Wilfart ◽  
Lucile Montagne ◽  
Howard Simmins ◽  
Jean Noblet ◽  
Jaap van Milgen
Keyword(s):  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Liquid Phase ◽  
Large Intestine ◽  
Dietary Fibre ◽  
Solid Phase ◽  
Latin Square ◽  
Fibre Content ◽  
Liquid Phases ◽  
Insoluble Fibre

Digestibility is the result of two competing processes: digestion and digesta transit. To develop or parameterise mechanistic models of digestion, both processes have to be quantified. The aim of this study was to determine the effect of insoluble dietary fibre on the transit in the gastrointestinal tract of pigs. Six barrows (33 kg initial body weight and fitted with two simple T-cannulas at the proximal duodenum and distal ileum) were used in a double 3 × 3 Latin square design. Pigs were offered diets differing in total dietary fibre content (170, 220 and 270 g/kg DM) at 4 h intervals. A single meal marked with YbO2and Cr-EDTA was used to determine the kinetics of markers concentrations of the solid and liquid phases, respectively. The mean retention time (MRT), calculated by the method of the moments, averaged 1, 4 and 38 h in the stomach, small intestine and large intestine, respectively. Increasing the insoluble fibre content in the diet had no effect on MRT in the stomach and decreased the MRT of both phases in the small intestine (P < 0·05). In the large intestine, increasing the insoluble fibre content decreased the MRT of the liquid phase (P = 0·02) and tended to decrease the MRT of the solid phase (P = 0·06). Transit of the solid phase in the large intestine was 4–8 h slower than transit of the liquid phase. Analysis of marker excretion curves indicated that the small and large intestine should be represented mathematically to have both a tubular (propulsion) and compartmental (mixing) structure.

Degassing Behavior and Solid State Reaction of Nano-Ti(CN) Base Cermets in Sintering

2008 ◽  
Vol 368-372 ◽  
pp. 1104-1106 ◽  
Author(s):  
Shu Zhu Zhou ◽  
Ye Xia Qin ◽  
Chun Lei Wan ◽  
Kai Qi Liu ◽  
Long Hao Qi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Solid State ◽  
Liquid Phase ◽  
Nitrogen Content ◽  
Oxygen Content ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Total Carbon ◽  
Two Phases

The chemical composition and solid state reaction of the nano-Ti(CN) base cermets in different sintering temperature were studied. The total carbon and oxygen content in compact were declined gradually with the increasing of sintering temperature, the nitrogen content in compact began to decline above 1100°C, the peak of de-gassing of N2 was formed before the emergence of liquid phase, the decomposition of N2 was arisen acutely above 1500°C. Mo2C and TaC diffused and took part in solid state reaction with Ti(CN) above 900°C, the solid state reaction was finished below 1200°C. WC diffused and took part in solid state reaction with Ti(CN) above 1100°C, it was dissolved below 1250°C, there were only two phases, Ti(CN) and Ni(Ni+Co), in the alloy.

scholarly journals Dietary fructose v. glucose in rats raises urinary excretion, true absorption and ileal solubility of magnesium but decreases magnesium retention

1994 ◽  
Vol 72 (4) ◽  
pp. 567-577 ◽  
Author(s):  
Annet Van Der Heijden ◽  
Gerrit J. Van Den Berg ◽  
Arnoldlna G. Lemmens ◽  
Anton C. Beynen
Keyword(s):  
Liquid Phase ◽  
Urinary Excretion ◽  
Solid Phase ◽  
Intraperitoneal Administration ◽  
Faecal Excretion ◽  
Apparent Absorption ◽  
True Absorption ◽  
Liquid Phases ◽  
Dietary Fructose ◽  
Stimulation Of

Apparent Mg absorption, that is Mg intake minus faecal excretion, was found to be greater in rats fed on diets containing fructose instead of glucose. This effect of fructose was accompanied by enhanced urinary excretion and diminished retention of Mg. True Mg absorption was then determined with the use of oral and intraperitoneal administration of tracer doses of 28Mg. True Mg absorption was significantly greater in rats fed on fructose. There was no significant effect of fructose v. glucose on faecal excretion of endogenous Mg. It was hypothesized that fructose enhances the solubility of Mg in the ileal lumen and thereby facilitates its absorption. The distribution of Mg between the solid and liquid phases of the ileum was determined in rats fed on either glucose or fructose. Fructose reduced the amount of Mg in the solid phase but raised both the amount and the concentration of Mg in the liquid phase. We conclude that the dietary-fructose-induced stimulation of Mg absorption in rats is caused by a raised solubility of ileal Mg. but the mechanism by which fructose exerts this effect and why it was not associated with a decrease in faecal excretion of endogenous Mg remain unknown. Dietary fructose v. glucose did not systematically affect the apparent absorption of Ca and P.

scholarly journals Analisis Komposisi dan Kandungan Karotenoid Total dan Vitamin A Fraksi Cair dan Padat Minyak Sawit Kasar (CPO) Menggunakan KCKT Detektor PDA

2012 ◽  
Vol 10 (2) ◽  
pp. 89
Author(s):  
M. Rio Syahputra ◽  
Ferry F Karwur ◽  
Leenawaty Limantara
Keyword(s):  
Liquid Phase ◽  
Vitamin A ◽  
Palm Oil ◽  
Solid Phase ◽  
Direct Method ◽  
Diode Array ◽  
Crude Palm Oil ◽  
Total Carotenoids ◽  
Carotenoid Composition ◽  
Two Phases

This study was carried out on two phases of Crude Palm Oil (CPO) to determine the total and composition ofcarotenoid and vitamin A content. Total of carotenoid was analyzed using spectrophotometer UV-Vis, and then theresult was calculated by Gross (1991) equation. The vitamin A content was calculated by NAS-NRC equation (1974).The type and composition of both phases of CPO were determined by Choo’s method (1994) by using HPLC withPhoto Diode Array (PDA) detector. The sample was prepared in two methods, with and without saponification. Theresult shows that total carotenoids in liquid and solid phase of CPO are 536 ± 13.2 g/g (liquid), 352 ± 17.7 μg/g(solid) and the vitamin A were 89.4 ± 2.2 RE (liquid), 58.7 ± 3.0 RE (solid), respectively. The carotenoid compositionsof both phases of CPO were dominated by - and -carotenes. The result shows that - and -carotenes preparedby saponification method in liquid phase are 29.03% and 60.88%, and without saponification (direct method) are28.14% and 59.44%. The result for solid phase shows that - and -carotenes by saponification are 25.89% and60.81%, and without saponification (direct method) are 30.00% and 56.92%. The research also shows the advantagesof using HPLC with PDA detector for identification and analysis of type and carotenoid composition.

scholarly journals Excess Li2O Additives to Promote Grain Boundary Growth and Improve Ionic Conductivity of LiTa2PO8 Solid Electrolytes

2021 ◽  
Vol 8 ◽  
Author(s):  
Qian Zhang ◽  
Fuhai Meng ◽  
Ruixiong Liao ◽  
Long Chen ◽  
Mengqian Xu ◽  
...  
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Ionic Conductivity ◽  
Grain Boundary ◽  
Solid Phase ◽  
Synthesis Method ◽  
Lithium Ion ◽  
Liquid Phase Sintering ◽  
Diffusion Activation Energy ◽  
The Impact

LiTa2PO8 (LTPO) is a new solid-state lithium ion electrolyte material reported in the latest research, which has high bulk ionic conductivity and low grain boundary ion conductivity. However, it is difficult to density with conventional sintering methods. Herein, in this work, the solid-phase synthesis method was used to prepared the LTPO solid-state electrolyte, and the influence of the amount of lithium on the structure and performance of LTPO electrolyte material was investigated. The results show that the excess Li2O does not increase other impurities and does not change the structure of the material, but the liquid phase produced by the excess Li2O can promote the elimination of interfacial pores, accelerate the direct bonding of grains and improve the ionic conductivity of grain boundary, thus improving the overall ionic conductivity of the material. Considering the volatilization of lithium and the impact of liquid phase sintering at high temperatures and the content restructuring, after adding 20 wt% excess formulation of Li2O, the resultant of LTPO density is 5.0 g/cm3, the density reaches 85.58%. As a result, the total ionic conductivity of the electrolyte is 3.28 × 10–4 S/cm at 25°C, and the Li-ion diffusion activation energy is 0.27 eV. In addition, after loading this electrolyte into a Li–Li symmetric battery, it is proved that the electrolyte has lithium ion transport performance and can be used in all-solid-state batteries. However, it is also found from cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) analysis that the interface between LTPO material and Li is unstable, and Ta5+ ions are reduced, which will be another key issue to be addressed in the future.

Solid-State Microwave Modification of Flocculants for Wastewater Treatment

2019 ◽  
Vol 23 (8) ◽  
pp. 26-31
Author(s):  
T.V. Shevchenko ◽  
Yu.V. Ustinova ◽  
A.M. Popov ◽  
Sh.A. Fairushin ◽  
V.P. Yustratov
Keyword(s):  
Shear Stress ◽  
Wastewater Treatment ◽  
Solid State ◽  
Liquid Phase ◽  
Physical Properties ◽  
Sedimentation Rate ◽  
Comparative Evaluation ◽  
Solid Phase ◽  
Phase Modification ◽  
Preliminary Preparation

Presents the results of research on the creation of effective technical preparations – flocculants based on polyacrylamide, modified by the physical action of microwaves with frequency 4.5 GHz on their solid phase. The change in the basic physical properties of the working solutions of flocculants was established (dissolution rate, shear stress values, efficiency and sedimentation rate). Mechanisms of microwave solid phase modification and features of dissolution of pretreated batches of solid polyelectrolyte fractions are proposed. On the basis of rheological studies of prepared working solutions of flocculants and test experiments on the flocculation of suspension a comparative evaluation of effectiveness of the action of microwaves on polyectrolyte during its preliminary preparation using solid phase and liquid phase modifications.

scholarly journals Molecular Analysis of Retrogradation of Corn Starches

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1764 ◽  
Author(s):  
Marek Sikora ◽  
Magdalena Krystyjan ◽  
Anna Dobosz ◽  
Piotr Tomasik ◽  
Katarzyna Walkowiak ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Correlation Time ◽  
Guar Gum ◽  
Corn Starch ◽  
Solid Phase ◽  
Amylose Content ◽  
Relaxation Times ◽  
Water Molecules ◽  
Correlation Times ◽  
Polymeric Network

Changes of the molecular dynamics of water in 5% corn starch pastes and 5% systems composed of starch and non-starchy hydrocolloid were studied during short and long term retrogradation. Low Field NMR was used to record mean correlation times (τc) of water molecules. This molecular parameter reflects the rotation of water molecules within the network of paste. Starches of different amylose and amylopectin content were selected for this study. Comparison of the changes of τc shows how particular polymers bind water molecules. During 90 days of storage, over 50% increase in mean correlation time was recorded in pastes of starches with high amylose content. This suggests that the formation of polymeric network is controlled by amylose to which water is binding. Amylopectin was found to influence the mobility of water in the pastes to a lesser extent with changes in mean correlation times of approximately 10–15% over 90 days. On retrogradation, amylopectin, Arabic and xanthan gums hindered the formation of solid phase structures. Guar gum evoked an increase in mean correlation times of approximately 40–50% during the prolonged process of changes of the molecular dynamics of water. This indicates continued expansion of the polymeric network. Mean correlation time available from spin–lattice and spin–spin relaxation times can be useful in the analysis of the rotational vibrations of the water molecules in biopolymeric structures.

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