scholarly journals DDPM-DEM Simulations of Particulate Flows in Human Tracheobronchial Airways

2013 ◽  
Author(s):  
Yu Feng ◽  
Clement Kleinstreuer
Keyword(s):  
Computational Models ◽  
Phase Model ◽  
Dispersed Phase ◽  
Particulate Flows ◽  
Lagrange Method ◽  
Dense Particle ◽  
Diverse Range ◽  
Particle Flows ◽  
Dominant Feature ◽  
The One

Dense particle-suspension flows in which particle-particle interactions are a dominant feature encompass a diverse range of industrial and geophysical contexts, e.g., slurry pipeline, fluidized beds, debris flows, sediment transport, etc. The one-way dispersed phase model (DPM), i.e., the conventional one-way coupling Euler-Lagrange method is not suitable for dense fluid-particle flows [1]. The reason is that such commercial CFD-software does not consider the contact between the fluid, particles and wall surfaces with respect to particle inertia and material properties. Hence, two-way coupling of the Dense Dispersed Phase Model (DDPM) combined with the Discrete Element Method (DEM) has been introduced into the commercial CFD software via in-house codes. As a result, more comprehensive and robust computational models based on the DDPM-DEM method have been developed, which can accurately predict the dynamics of dense particle suspensions. Focusing on the interaction forces between particles and the combination of discrete and continuum phases, inhaled aerosol transport and deposition in the idealized tracheobronchial airways [2] was simulated and analyzed, generating more physical insight. In addition, it allows for comparisons between different numerical methods, i.e., the classical one-way Euler-Lagrange method, two-way Euler-Lagrange method, EL-ER method [3], and the present DDPM-DEM method, considering micron- and nano-particle transport and deposition in human lungs.

Computational models of filtration gas combustion

2017 ◽  
Vol 32 (2) ◽  
Author(s):  
Yuri M. Laevsky ◽  
Tatyana A. Nosova
Keyword(s):  
Heat Flow ◽  
Numerical Experiments ◽  
Computational Models ◽  
Two Dimensional ◽  
Multidimensional Model ◽  
Gas Combustion ◽  
Total Enthalpy ◽  
Diffusive Flow ◽  
Temperature Heat ◽  
The One

AbstractA multidimensional model of filtration gas combustion is presented. The model is based on the system of conservation laws of ‘temperature – heat flow’, ‘mass–diffusive flow’ types with introducing the concept of total enthalpy flow. Results of numerical experiments are presented for the one- and two-dimensional problems for different conditions and parameters.

scholarly journals Image and exposure: Envisioning genetics as a forensic-surveillance matrix

2013 ◽  
Vol 11 (3) ◽  
pp. 237-251
Author(s):  
Erin Kruger
Keyword(s):  
National Security ◽  
Criminal Law ◽  
Genetic Data ◽  
Crime Scene ◽  
Dna Profiling ◽  
Diverse Range ◽  
The Status ◽  
Legal Domain ◽  
The One ◽  
Identification Model

This paper takes the ‘visual’ as the primary subject to engage in a dialogue about surveillance by drawing upon the specific case of the genetic image. Specifically, the genetic image has shifted from the ‘one gene for one identification’ model used in the criminal law to, what are now, categorical, contextual and pattern-based configurations of DNA profiling that are able to compare multiple genetic samples in a singular image. The ability to profile genetics for law and security purposes is, thus, protracting well beyond the confines of the criminal legal domain (i.e. the crime scene, forensic laboratory, courtroom) and into the realm of surveillance: national security, defense, immigration, military and even humanitarian domains. Such a notable transition in visual profiling has also been met with a synonymous reformation in the status of genetic data as it converts from evidence in the realm of criminal law to, now, intelligence in the surveillance-based contexts noted above. This visual reclassification of genetic data reorients DNA to an informing, as opposed to an identifying role. Finally, how experts, scientists, legalists and other relevant practitioners conceive and represent ‘truth’ and ‘trust’ in light of an increasingly diverse range of genetic imagery is subject for discussion.

scholarly journals New Insights into Annual and Semiannual Cycles of Sea Level Pressure

2012 ◽  
Vol 140 (4) ◽  
pp. 1347-1355 ◽  
Author(s):  
Ge Chen ◽  
Chengcheng Qian ◽  
Caiyun Zhang
Keyword(s):  
Sea Level ◽  
Southern Oscillation ◽  
Global Ocean ◽  
Boreal Winter ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
The North ◽  
Dominant Feature ◽  
The One ◽  
The North Pacific

Sea level pressure (SLP) acts, on the one hand, as a “bridge parameter” to which geophysical properties at the air–sea interface (e.g., wind stress and sea surface height) are linked, and on the other hand, as an “index parameter” by which major atmospheric oscillations, including the well-known Southern Oscillation, are defined. Using 144 yr (1854–1997) of extended reconstructed SLP data, seasonal patterns of its variability are reinvestigated in detail. New features on fundamental structure of its annual and semiannual cycles are revealed in two aspects. First, the spatiotemporal patterns of yearly and half-yearly SLPs are basically determined by a network of “amphidromes,” which are surrounded by rotational variations. Fourteen cyclonic and anticyclonic annual SLP amphidromes (half each and often in pair) are found in the global ocean, while the numbers of the two types of semiannual amphidrome are 11 and 9, respectively. The second dominant feature in SLP variability is the pattern of oscillation or seesaw for both annual and semiannual components. At least eight oscillation zones are identified for the annual cycle, which can be categorized into a boreal winter mode and an austral winter mode. As for the semiannual cycle, the seesaw pattern is geographically divided into three regimes: the North Pacific regime, the North Atlantic regime, and the Southern Ocean regime. These findings serve as a new contribution to characterizing and understanding the seasonality of the global ocean–atmosphere system.

Locally Recurrent Neural Networks and Their Applications

2010 ◽  
pp. 195-222
Author(s):  
Todor D. Ganchev
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Computational Models ◽  
Machine Learning Techniques ◽  
Spatial Correlations ◽  
Temporal Correlations ◽  
Learning Techniques ◽  
Locally Recurrent ◽  
The One ◽  
And Control

In this chapter we review various computational models of locally recurrent neurons and deliberate the architecture of some archetypal locally recurrent neural networks (LRNNs) that are based on them. Generalizations of these structures are discussed as well. Furthermore, we point at a number of realworld applications of LRNNs that have been reported in past and recent publications. These applications involve classification or prediction of temporal sequences, discovering and modeling of spatial and temporal correlations, process identification and control, etc. Validation experiments reported in these developments provide evidence that locally recurrent architectures are capable of identifying and exploiting temporal and spatial correlations (i.e., the context in which events occur), which is the main reason for their advantageous performance when compared with the one of their non-recurrent counterparts or other reasonable machine learning techniques.

Can the principle of ‘one person – one language’ be disregarded as unrealisttcally elitist?

1998 ◽  
Vol 21 (1) ◽  
pp. 41-56 ◽  
Author(s):  
Susanne Döpke
Keyword(s):  
Dual Language ◽  
Language Maintenance ◽  
Diverse Range ◽  
Language Differentiation ◽  
The One

Early accounts of the achievement of bilingualism in children of dual-language couples stressed the importance of clear language differentiation according to a principle called ‘one person-one language’. This approach has come under attack recently as being elitist and atypical of bilinguals, and largely unrealistic. Proponents of these criticisms fail to see the benefits that knowledge of the factors which can make bilingualism succeed under these conditions can have for families in a diverse range of bilingual situations. The ‘one person-one language’ principle will be conceptualised as successful because it invokes principles of language maintenance relevant for bilingual societies on the level of individual families. This is seen as important in situations where societal support is minimal or non-existent.

scholarly journals Estimates for the Effective Permeability of Intact Granite Obtained from the Eastern and Western Flanks of the Canadian Shield

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 667
Author(s):  
A. P. S. Selvadurai ◽  
A. Blain-Coallier ◽  
P. A. Selvadurai
Keyword(s):  
Effective Permeability ◽  
Computational Models ◽  
Granitic Rock ◽  
Geometric Mean ◽  
Surface Region ◽  
Canadian Shield ◽  
Surface Permeability ◽  
Experimental Values ◽  
The One ◽  
High Level

Granitic rock from the western part of the Canadian Shield is considered as a potential host rock for the siting of a deep geological repository for the storage of heat-emitting high-level nuclear fuel waste. The research program focused on the use of surface permeability measurements conducted at 54 locations on a 300 mm cuboid of granite, obtained from the Lac du Bonnet region in Manitoba, to obtain an estimate for the effective permeability of the cuboid. Companion experiments are conducted on a 280 mm cuboid of granite obtained from Stanstead, Quebec, located in the eastern part of the Canadian Shield. The surface permeabilities for the cuboids of granite are developed from theoretical relationships applicable to experimental situations where steady flow is initiated at a sealed annular surface region with a pressurized central domain. The experimental values for the surface permeability are used with a kriging procedure to estimate the permeability variations within the cuboidal region. The spatial variations of permeability are implemented in computational models of the cuboidal regions to determine the one-dimensional permeabilities in three orthogonal directions. The effective permeability of the granite cuboids is estimated by appeal to the geometric mean. The research provides a non-destructive methodology for estimating the effective permeability of large specimens of rock and the experiments performed give estimates for the effective permeability of the two types of granitic rock obtained from the western and eastern flanks of the Canadian Shield.

A new agent-based simulation model of bilateral negotiation

2019 ◽  
Vol 31 (1) ◽  
pp. 115-148
Author(s):  
Frieder Lempp
Keyword(s):  
Simulation Model ◽  
Computational Models ◽  
Future Research ◽  
Bilateral Negotiation ◽  
Agent Based Simulation ◽  
Diverse Range ◽  
Content Type ◽  
Agent Based ◽  
Negotiation Strategies ◽  
Negotiation Research

Purpose The purpose of this paper is to introduce a new agent-based simulation model of bilateral negotiation based on a synthesis of established theories and empirical studies of negotiation research. The central units of the model are negotiators who pursue goals, have attributes (trust, assertiveness, cooperativeness, creativity, time, etc.) and perform actions (proposing and accepting offers, exchanging information, creating value, etc). Design/methodology/approach Methodologically, the model follows the agent-based approach to modeling. This approach is chosen because negotiations can be described as complex, non-linear systems involving autonomous agents (i.e. the negotiators), who interact with each other, pursue goals and perform actions aimed at achieving their goals. Findings This paper illustrates how the model can simulate experiments involving variables such as negotiation strategy, creativity, reservation value or time in negotiation. An example simulation is presented which investigates the main and interaction effects of negotiators’ reservation value and their time available for a negotiation. A software implementation of the model is freely accessible at https://tinyurl.com/y7oj6jo8. Research limitations/implications The model, as developed at this point, provides the basis for future research projects. One project could address the representation of emotions and their impact on the process and outcome of negotiations. Another project could extend the model by allowing negotiators to convey false information (i.e. to bluff). Yet another project could be aimed at refining the routines used for making and accepting offers with a view to allow parties to reach partial settlements during a negotiation. Practical implications Due to its broad scope and wide applicability, the model can be used by practitioners and researchers alike. As a decision-support system, the model allows users to simulate negotiation situations and estimate the likelihood of negotiation outcomes. As a research platform, it can generate simulation data in a cost- and time-effective way, allowing researchers to simulate complex, large-N studies at no cost or time. Originality/value The model presented in this paper synthesizes in a novel way a comprehensive range of concepts and theories of current negotiation research. It complements other computational models, in that it can simulate a more diverse range of negotiation strategies (distributive, integrative and compromise) and is applicable to a greater variety of negotiation scenarios.

Hybrid Eulerian Multiphase-Dense Discrete Phase Model Approach for Numerical Simulation of Dense Particle-Laden Turbulent Flows Within Vertical Multi-Stage Cyclone Heat Exchanger

2018 ◽  
Author(s):  
Eugen-Dan Cristea ◽  
Pierangelo Conti
Keyword(s):  
Heat Exchanger ◽  
Carrier Phase ◽  
Phase Model ◽  
Cement Kiln ◽  
Dispersed Phase ◽  
Discrete Phase Model ◽  
Dry Process ◽  
Rotary Cement Kiln ◽  
Multi Stage ◽  
Discrete Phase

This article describes a CFD engineering application developed to investigate numerically the multiphase, non-isothermal, turbulent flow physics within the suspension preheater of a dry-process rotary cement kiln. The multi–stage cyclone preheater is a counter-current heat exchanger. We used the CFD flow solver ANSYS-Fluent R18.1. to accomplish this task. The hybrid Eulerian multiphase-dense discrete phase model is a coupled Eulerian-Lagrangian technique. The primary carrier-phase is treated as a continuum by solving the Navier-Stokes equations, while the secondary discrete dispersed-phase is solved by tracking the particle parcels through the calculated flow field. The multiphase turbulence of the carrier-phase is modeled using the Reynolds stress transport model. The dispersed-phase interactions are modeled through the specific collisions models provided by the kinetic theory of granular flow and/or discrete element method. The Eulerian multiphase-DDPM method provided a quiet stable solution for a medium/high mass loading (solid to gas mass ratio 0.89:1). The four-stage cyclone suspension preheater is analyzed for its operating performance i.e. overall pressure drop and global collection efficiency of cyclone stages, calcination degree at bottom cyclone stage, flue gas temperature at 1st. cyclone stage and availability to get more insight of very complex multi-phase flow patterns within this equipment. The set of industrial measurements, collected during a heat and mass balance of a dry process rotary cement kiln, were used to verify and to validate part of the simulation results.

Sign in / Sign up

Export Citation Format

Share Document