Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Origin of Self-preservation Effect for Hydrate Decomposition: Coupling of Mass and Heat Transfer Resistances.

ABSTRACT: Gas hydrates could show an unexpected high stability at conditions out of thermodynamic equilibrium, which is called the self-preservation effect. The mechanism of the effect for methane hydrates is here investigated via molecular dynamics simulations, in which an NVT/E method is introduced to represent different levels of heat transfer resistance. Our simulations suggest a coupling between the mass transfer resistance and heat transfer resistance as the driving mechanism for self-preservation effect. We found that the hydrate is initially melted from the interface, and then a solid-like water layer with temperature-dependent structures is formed next to the hydrate interface that exhibits fractal feature, followed by an increase of mass transfer resistance for the diffusion of methane from hydrate region. Furthermore, our results indicate that heat transfer resistance is a more fundamental factor, since it facilitates the formation of the solid-like layer and hence inhibits the further dissociation of the hydrates. The self-preservation effect is found to be enhanced with the increase of pressure and particularly the decrease of temperature. Kinetic equations based on heat balance calculations is also developed to describe the self-preservation effect, which reproduces our simulation results well and provides an association between microscopic and macroscopic properties.

SUBMITTER: Bai D

PROVIDER: S-EPMC4589738 | biostudies-other | 2015

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Modeling Mass and Heat Transfer in Multiphase Coffee Aroma Extraction.

Project description:Instant coffee manufacture involves the aqueous extraction of soluble coffee components followed by drying to form a soluble powder. Loss of volatile aroma compounds during concentration through evaporation can lower product quality. One method of retaining aroma is to steam-strip volatiles from the coffee and add them back to a concentrated coffee solution before the final drying stage. A better understanding of the impact of process conditions on the aroma content of the stripped solution will improve product design stages. In this context, we present a multiscale model for aroma extraction describing (i) the release from the matrix, (ii) intraparticle diffusion, (iii) transfer into water and steam, and (iv) advection through the column mechanisms. Results revealed (i) the existence of three different types of compound behavior, (ii) how aroma physiochemistry determines the limiting kinetics of extraction, and (iii) that extraction for some aromas can be inhibited by the interaction with other coffee components.

| S-EPMC7304076 | biostudies-literature

Improving heat and mass transfer rates through continuous drop-wise condensation.

Project description:Drop-wise condensation (DWC) has been the focus of scientific research in vapor condensation technologies since the 20th century. Improvement of condensation rate in DWC is limited by the maximum droplet a condensation surface could sustain and the frequency of droplet shedding. Furthermore, The presence of non-condensable gases (NCG) reduces the condensation rate significantly. Here, we present continuous drop-wise condensation to overcome the need of hydrophobic surfaces while yet maintaining micron-sized droplets. By shifting focus from surface treatment to the force required to sweep off a droplet, we were able to utilize stagnation pressure of jet impingement to tune the shed droplet size. The results show that droplet size being shed can be tuned effectively by tuning the jet parameters. our experimental observations showed that the effect of NCG is greatly alleviated by utilizing this technique. An improvement by multiple folds in mass transfer compactness factor compared to state-of-the-art dehumidification technology was possible.

| S-EPMC8490593 | biostudies-literature

Multiphysics modelling of photon, mass and heat transfer in coral microenvironments.

Project description:Coral reefs are constructed by calcifying coral animals that engage in a symbiosis with dinoflagellate microalgae harboured in their tissue. The symbiosis takes place in the presence of steep and dynamic gradients of light, temperature and chemical species that are affected by the structural and optical properties of the coral and their interaction with incident irradiance and water flow. Microenvironmental analyses have enabled quantification of such gradients and bulk coral tissue and skeleton optical properties, but the multi-layered nature of corals and its implications for the optical, thermal and chemical microenvironment remains to be studied in more detail. Here, we present a multiphysics modelling approach, where three-dimensional Monte Carlo simulations of the light field in a simple coral slab morphology with multiple tissue layers were used as input for modelling the heat dissipation and photosynthetic oxygen production driven by photon absorption. By coupling photon, heat and mass transfer, the model predicts light, temperature and O2 gradients in the coral tissue and skeleton, under environmental conditions simulating, for example, tissue contraction/expansion, symbiont loss via coral bleaching or different distributions of coral host pigments. The model reveals basic structure-function mechanisms that shape the microenvironment and ecophysiology of the coral symbiosis in response to environmental change.

| S-EPMC8437025 | biostudies-literature

Mapping Hebbian Learning Rules to Coupling Resistances for Oscillatory Neural Networks.

Project description:Oscillatory Neural Network (ONN) is an emerging neuromorphic architecture with oscillators representing neurons and information encoded in oscillator's phase relations. In an ONN, oscillators are coupled with electrical elements to define the network's weights and achieve massive parallel computation. As the weights preserve the network functionality, mapping weights to coupling elements plays a crucial role in ONN performance. In this work, we investigate relaxation oscillators based on VO2 material, and we propose a methodology to map Hebbian coefficients to ONN coupling resistances, allowing a large-scale ONN design. We develop an analytical framework to map weight coefficients into coupling resistor values to analyze ONN architecture performance. We report on an ONN with 60 fully-connected oscillators that perform pattern recognition as a Hopfield Neural Network.

| S-EPMC8606813 | biostudies-literature

Evaluation of Terpene Decomposition in Kaffir Lime Juice during Storage Using Gas Chromatography–Mass Spectrometry and Proton Transfer Reaction–Mass Spectrometry

Project description: Not available

| S-EPMC11243363 | biostudies-literature

Microscopic Origin of Strain Hardening in Methane Hydrate.

Project description:It has been reported for a long time that methane hydrate presents strain hardening, whereas the strength of normal ice weakens with increasing strain after an ultimate strength. However, the microscopic origin of these differences is not known. Here, we investigated the mechanical characteristics of methane hydrate and normal ice by compressive deformation test using molecular dynamics simulations. It is shown that methane hydrate exhibits strain hardening only if the hydrate is confined to a certain finite cross-sectional area that is normal to the compression direction. For normal ice, it does not present strain hardening under the same conditions. We show that hydrate guest methane molecules exhibit no long-distance diffusion when confined to a finite-size area. They appear to serve as non-deformable units that prevent hydrate structure failure, and thus are responsible for the strain-hardening phenomenon.

| S-EPMC4806379 | biostudies-literature

Closed-form solution of oscillating Maxwell nano-fluid with heat and mass transfer.

Project description:The primary goal of this article is to analyze the oscillating behavior of Maxwell Nano-fluid with regard to heat and mass transfer. Due to high thermal conductivity of engine oil is taken as a base fluid and graphene Nano-particles are introduced in it. Coupled partial differential equations are used to model the governing equations. To evaluate the given differential equations, certain dimensionless factors and Laplace transformations are used. The analytical solution is obtained for temperature, concentration and velocity. The temperature and concentration gradient are also finds to analyze the rate of heat and mass transfer. As a special case, the solution for Newtonian fluid is discussed. Finally, the behaviors of various physical factors are studied graphically for both sine and cosine oscillation and give physical meanings to the parameters.

| S-EPMC9288494 | biostudies-literature

Heat capacity and decomposition of rimantadine hydrochloride.

Project description:Heat capacities of the antiviral drug rimantadine hydrochloride in the crystalline state were measured by adiabatic calorimetry and differential scanning calorimetry in the temperature range from (7 to 453) K. A broad low-enthalpy solid-state phase anomaly was detected between (170 and 250) K. Thermodynamic functions for crystalline rimantadine hydrochloride were derived. Decomposition of the studied compound was probed by the Knudsen effusion method and thermogravimetry with the support of quantum chemical calculations. The enthalpy of decomposition of rimantadine hydrochloride into the corresponding amine and hydrogen chloride was estimated from those data. The thermodynamic functions of the corresponding amine in the ideal gaseous state, including enthalpy of formation, were obtained using statistical thermodynamics with the necessary molecular parameters computed using quantum chemical methods. The enthalpy of formation of crystalline rimantadine hydrochloride was estimated.

| S-EPMC8519015 | biostudies-literature

Darcy-Forchheimer hybrid nanofluid flow over a stretching curved surface with heat and mass transfer.

Project description:The present article provides a detailed analysis of the Darcy Forchheimer flow of hybrid nanoliquid past an exponentially extending curved surface. In the porous space, the viscous fluid is expressed by Darcy-Forchheimer. The cylindrical shaped carbon nanotubes (SWCNTs and MWCNTs) and Fe3O4 (iron oxide) are used to synthesize hybrid nanofluid. At first, the appropriate similarity transformation is used to convert the modeled nonlinear coupled partial differential equations into nonlinear coupled ordinary differential equations. Then the resulting highly nonlinear coupled ordinary differential equations are analytically solved by the utilization of the "Homotopy analysis method" (HAM) method. The influence of sundry flow factors on velocity, temperature, and concentration profile are sketched and briefly discussed. The enhancement in both volume fraction parameter and curvature parameter k results in raises of the velocity profile. The uses of both Fe3O4 and CNTs nanoparticles are expressively improving the thermophysical properties of the base fluid. Apart from this, the numerical values of some physical quantities such as skin friction coefficients, local Nusselt number, and Sherwood number for the variation of the values of pertinent parameters are displayed in tabular forms. The obtained results show that the hybrid nanofluid enhances the heat transfer rate 2.21%, 2.1%, and 2.3% using the MWCNTs, SWCNTs, and Fe3O4 nanomaterials.

| S-EPMC8104385 | biostudies-literature

The role of turbulent hydrodynamics and surface morphology on heat and mass transfer in corals.

Project description:Corals require efficient heat and mass transfer with the overlying water column to support key biological processes, such as nutrient uptake and mitigation of thermal stress. Transfer rates are primarily determined by flow conditions, coral morphology and the physics of the resulting fluid-structure interaction, yet the relationship among these parameters is poorly understood especially for wave-dominated coral habitats. To investigate the interactive effects of these factors on fluxes of heat and mass, we measure hydrodynamic characteristics in situ over three distinct surface morphologies of massive stony corals in a Panamanian reef. Additionally, we implement a numerical model of flow and thermal transport for both current and wave conditions past a natural coral surface, as well as past three simplified coral morphologies with varying ratios of surface roughness spacing-to-height. We find oscillatory flow enhances rates of heat and mass transfer by 1.2-2.0× compared with unidirectional flow. Additionally, increases in Reynolds number and in surface roughness ratio produce up to a 3.3× and a 2.0× enhancement, respectively. However, as waves begin to dominate the flow regime relative to unidirectional currents, the underlying physical mechanisms mediating transfer rates shift from predominantly turbulence-driven to greater control by inertial accelerations, resulting in larger heat and mass transfer for small surface roughness ratios. We show that for rough corals in wave-dominated flows, novel trade-off dynamics for heat and mass transfer exist between broadly spaced roughness that enhances turbulence production versus narrowly spaced roughness that produces greater surface area. These findings have important implications for differential survivorship during heat-induced coral bleaching, particularly as thermal stress events become increasingly common with global climate change.

| S-EPMC6303798 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data