scholarly journals Thermodynamic Analysis of Myelin Basic Protein Adsorbed on Liquid Crystalline Dioleoylphosphatidylcholine Monolayer

Scanning ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Zhang Lei ◽  
Sun Runguang ◽  
Hao Changchun ◽  
Yang Huihui ◽  
Hu Chengxi
Keyword(s):  
Myelin Basic Protein ◽  
Surface Pressure ◽  
Liquid Crystalline ◽  
Basic Protein ◽  
Hydrophobic Interactions ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Molecular Area ◽  
Unsaturated Lipid ◽  
Mass Conservation Equation

To investigate the stability and dynamic characteristics of monolayer adsorbed on unsaturated lipid dioleoylphosphatidylcholine (DOPC) with varying concentrations of myelin basic protein (MBP), the system is studied by applying Langmuir technique and making atomic force microscope (AFM) observation, which is based on the mass conservation equation analysis method referred to in the thermodynamics theory. As indicated by surface pressure-mean molecular area (π−A) and surface pressure-adsorption time (π−T) isotherms, the physical properties of monolayer derived from the interaction of varying concentrations of MBP with liquid crystalline unsaturated lipid DOPC molecules were qualitatively studied. As revealed by surface morphology analysis with AFM, the micro region was expanded as the concentration of MBP in the subphase was on the increase, suggesting that hydrophobic interactions led to the MBP insertion, thus causing accumulation of the MBP on the surface of the monolayer. Experimental results have demonstrated that the partition coefficient of the interaction between MBP and unsaturated phospholipid DOPC and the molecular area of MBP adsorbed on the monolayer film was calculated using the mass conservation equation. In addition, not only does the varying concentration of MBP in the subphase exerts significant effects on the arrangement and conformation of DOPC monolayer, it also has certain guiding significance to exploring the structural changes to biofilm supramolecular aggregates as well as the pathogenesis and treatment of related diseases.

Transport of Microorganisms in the Underground – Processes, Experiments and Simulation Models

1991 ◽  
Vol 24 (2) ◽  
pp. 309-314 ◽  
Author(s):  
G. Teutsch ◽  
K. Herbold-Paschke ◽  
D. Tougianidou ◽  
T. Hahn ◽  
K. Botzenhart
Keyword(s):  
Simulation Models ◽  
Mass Conservation ◽  
Breakthrough Curves ◽  
Conservation Equation ◽  
Retardation Factor ◽  
Natural Systems ◽  
Laboratory Setup ◽  
Preliminary Model ◽  
Sand And Gravel ◽  
Mass Conservation Equation

In this paper the major processes governing the persistence and underground transport of viruses and bacteria are reviewed in respect to their importance under naturally occurring conditions. In general, the simulation of the governing processes is based on the macroscopic mass-conservation equation with the addition of some filter and/or retardation factor and a decay coefficient, representing the natural “die-off” of the microorganisms. More advanced concepts try to incorporate growth and decay coefficients together with deposition and declogging factors. At present, none of the reported concepts has been seriously validated. Due to the complexity of natural systems and the pathogenic properties of some of the microorganisms, experiments under controlled laboratory conditions are required. A laboratory setup is presented in which a great variety of natural conditions can be simulated. This comprises a set of 1 metre columns and an 8 metre stainless-steel flume with 24 sampling ports. The columns are easily filled and conditioned and therefore used to study the effects of different soil-microorganism combinations under various environmental conditions. In the artificial flume natural underground conditions are simulated using sand and gravel aquifer material from the river Neckar alluvium. A first set of results from the laboratory experiments is presented together with preliminary model simulations. The large variety of observed breakthrough curves and recovery for the bacteria and viruses under investigation demonstrates the great uncertainty encountered in microbiological risk assessment.

Macroscopic Modeling of Pedestrian Flow Considering the Herd Behavior

2013 ◽  
Vol 444-445 ◽  
pp. 906-911
Author(s):  
Yan Qun Jiang
Keyword(s):  
Numerical Experiments ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Behavioral Characteristics ◽  
Herd Behavior ◽  
Pedestrian Flow ◽  
Evacuation Time ◽  
Macroscopic Modeling ◽  
Pedestrian Simulation ◽  
Mass Conservation Equation

This paper aims to mimic the herd behavior of pedestrian flow, i.e., the tendency towards majority when a congestion occurs, by macroscopic modeling approach. The macroscopic pedestrian simulation model is composed of a mass-conservation equation and a simple model to reflect behavioral characteristics of pedestrians based on a specific traffic situation. Numerical experiments are designed to show some preliminary results, e.g. the beneficial effect of herding on evacuation time in some situations.

On the effectiveness of shelter-in-place as a measure to reduce harm from atmospheric releases

2014 ◽  
Vol 12 (3) ◽  
pp. 245
Author(s):  
Shuming Du, PhD
Keyword(s):  
Exchange Rate ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Hazardous Material ◽  
Air Exchange Rate ◽  
Chemical Attack ◽  
Chemical Accident ◽  
Atmospheric Releases ◽  
Toxic Load ◽  
Mass Conservation Equation

Shelter-in-place (SIP) is recommended by numerous entities as a measure to reduce harm in the event of a chemical accident or chemical attack taking place in the atmosphere. This article, based on solving mass conservation equation for indoor hazardous material, examines how effective SIP is to reduce the harm. It is shown that SIP can be effective when the shelter's air exchange rate is low and when the release duration is short. The effectiveness is strongly affected by the hazardous material itself: SIP is more effective for hazardous material with higher toxic load exponent. Another finding is that leaving the shelter promptly after the event can also be critical.

Macroscopic Simulation of Pedestrian Flow through a Bottleneck

2011 ◽  
Vol 97-98 ◽  
pp. 1168-1175 ◽  
Author(s):  
Yan Qun Jiang ◽  
Peng Zhang
Keyword(s):  
Traffic Congestion ◽  
Mass Conservation ◽  
Flow Speed ◽  
Conservation Equation ◽  
Comfort Level ◽  
Macroscopic Model ◽  
Pedestrian Flow ◽  
Macroscopic Simulation ◽  
Flow Through ◽  
Mass Conservation Equation

The paper deals with the macroscopic type modelling of the unidirectional pedestrian flow moving through a corridor with a bottleneck. The macroscopic model of pedestrian flow is the two-dimensional Lighthill-Whitham-Richards model described as a mass conservation equation. The characteristic feature of pedestrian route choice is that pedestrians in the corridor try to minimize the instantaneous travel time and improve the comfort level. The model equation is solved numerically by the discontinuous Galerkin method. Numerical results visualize the ability of the model to predict macroscopic characteristics of pedestrian flow through bottlenecks, i.e. the spatial distribution of the flow speed and density, as well as the formation and dissipation of traffic congestion in the corridor. They also validate that congestion is caused by the limited capacity of the bottleneck.

scholarly journals Y. S. Hu, H. J. Wei, B. Yu, O. X. Yang, J. Wang, J. Wu. Research on the vapor injection of two-stage rotary compressor / trans. from Engl. M. A. Fedorova

2021 ◽  
Vol 5 (4) ◽  
pp. 65-74
Author(s):  
M. A. Fedorova ◽  
Keyword(s):  
Flow Characteristics ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Rotary Compressor ◽  
Two Stage ◽  
Injection Channel ◽  
Injection Flow ◽  
Vapor Injection ◽  
Intermediate Chamber ◽  
Mass Conservation Equation

In order to understand the vapor injection flow characteristics of two-stage rotary compressor in the course of compression, a mathematical model based on mass conservation equation, energy equation and thermodynamic identity was established and proved by P-V diagram testing results. Some useful conclusions about pressure in the intermediate chamber and mass flow of vapor injection in the course of compression were also given out. The results show that, gas backflow between the intermediate chamber and the vapor injection channel is an important defection of two-stage rotary compressor which can be solved by the application of injection valve in vapor injection channel. The injection valve can obviously reduce the gas backflow and the power loss in the course of compression while increasing the pressure fluctuation in the intermediate chamber. Experiments show that the COP of two-stage rotary compressor with the injection valve increased by over 2% in ASHRAE/T working condition.

On a New Passive Scalar Equation With Variable Mass Diffusivity

2008 ◽  
Author(s):  
Fabio Gori ◽  
Andrea Boghi
Keyword(s):  
Mass Flux ◽  
Variable Mass ◽  
Mass Conservation ◽  
Passive Scalar ◽  
Conservation Equation ◽  
Average Concentration ◽  
Concentration Fluctuation ◽  
Mass Diffusivity ◽  
Coupled Solution ◽  
Mass Conservation Equation

The present work investigates the mass conservation equation of a Newtonian and non-Newtonian fluid in turbulent flow with variable mass diffusivity. The mass conservation equation is considered with the fluctuating terms in the concentration as well as in the mass diffusivity and is written for the average concentration, for the fluctuating concentration one as well as for the square of the fluctuating concentration. A new term appears in the form of product of the fluctuating mass diffusivity to the space gradient of the concentration fluctuation. This new term is interpreted and introduced in the mass conservation equation of the square of the fluctuating concentration where other new terms are also appearing. A possible physical interpretation is given to the different terms. Assuming several relations between mass diffusivity and concentration it is then possible to write expressions for the average and the fluctuating mass concentration which can be simplified on the basis of physical and mathematical considerations. Specifically, the mass flux is then expressed as the product of the derivative of the mass diffusivity to the gradient of the square of the mass fluctuation. Further considerations make possible to write a new mass conservation equation of the average concentration which include a new term which takes into account the space gradient of the mass flux. The mass conservation equation can be solved with the coupled solution of the equation of the square of the concentration fluctuation.

FIRST-ORDER MACROSCOPIC MODELLING OF HUMAN CROWD DYNAMICS

2008 ◽  
Vol 18 (supp01) ◽  
pp. 1217-1247 ◽  
Author(s):  
V. COSCIA ◽  
C. CANAVESIO
Keyword(s):  
Space Dimension ◽  
Mass Conservation ◽  
Initial Boundary ◽  
Conservation Equation ◽  
Initial Boundary Value Problems ◽  
First Order ◽  
Crowd Dynamics ◽  
Initial Boundary Value ◽  
Human Crowd ◽  
Mass Conservation Equation

This paper deals with the mathematical modelling of crowd dynamics within the framework of continuum mechanics. The method uses the mass conservation equation closed by phenomenological models linking the local velocity to density and density gradients. The closures take into account movement in more than one space dimension, presence of obstacles, pedestrian strategies, and modelling of panic conditions. Numerical simulations of the initial-boundary value problems visualize the ability of the models to predict several interesting phenomena related to the complex system under consideration.

scholarly journals Flow simulation of a firn-covered cold glacier

1997 ◽  
Vol 24 ◽  
pp. 242-248 ◽  
Author(s):  
Olivier Gagliardini ◽  
Jacques Meyssonnier
Keyword(s):  
Numerical Simulation ◽  
Flow Simulation ◽  
Mass Conservation ◽  
Conservation Equation ◽  
The Finite Element Method ◽  
Density Profiles ◽  
Coupled Problem ◽  
Stationary Conditions ◽  
Mass Conservation Equation

A numerical simulation of the flow of the cold glacier of Dôme du Goûter (4304 m, Mont Blanc, France) is presented. Owing to the large thickness of the firn layer, the simulation was done by using a rheological model for porous ice derived from a model for ceramic sintering and adapted to fit available data on in situ measured density profiles and firn mechanical behaviour. The flow calculation was made under the assumptions of axisymmetric geometry and stationary conditions, by solving a coupled problem. For a given density field, the velocities were obtained by the finite-element method. Then the integration of the mass-conservation equation along the streamlines derived from this velocity field gave the corresponding stationary densities. The results of the numerical simulation, besides the velocity and density fields, are the age of the ice along the streamlines. They are compared with observation and field data.

scholarly journals Testing Numerical Models of Glacier Flow

1979 ◽  
Vol 24 (90) ◽  
pp. 508-509
Author(s):  
E. D. Waddington
Keyword(s):  
Mass Balance ◽  
Numerical Models ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Diffusion Parameters ◽  
Analytical Work ◽  
Model Dynamics ◽  
Correct Response Time ◽  
Glacier Flow ◽  
Mass Conservation Equation

AbstractThe recent glaciological literature contains a number of numerical simulations of ice-mass flow based on the mass conservation equation. Although rather complex ice masses have been modelled, there has been little discussion of the necessary tests for correct response time and amplitudes in the models. The analytical work of J. F. Nye (1960, 1963[a], 1963[b], 1965[a],1965[b]) on the response of a steady-state glacier to perturbations in its mass balance provides an excellent test of model dynamics. Only when properly verified can the numerical model be used to extend knowledge of glacier response to more general cases where analytical solutions are unavailable. The model in this paper is checked against Nye’s calculations of response to a step increase in mass balance. It is then used to extend Nye’s results by finding the time constants for diffusion parameters other than 0 and 1.

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