scholarly journals Influence of the Visitor Walking on Airflow and the Bioaerosol Particles in Typical Open Tomb Chambers: An Experimental and Case Study

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 538
Author(s):  
Zhijian Liu ◽  
Minnan Wu ◽  
Hongwei Cao ◽  
Yongxin Wang ◽  
Rui Rong ◽  
...  
Keyword(s):  
Potential Risk ◽  
Deposition Time ◽  
Scientific Basis ◽  
Discrete Phase Model ◽  
Migration Mechanism ◽  
Discrete Phase ◽  
And Migration ◽  
The Impact ◽  
Experimental Sampling

Effective maintenance of ancient buildings is paid more and more attention worldwide. Many ancient buildings with high inheritance value were gradually destroyed, especially for murals in the open tombs. The bioaerosol particles (BPs) are the major source of contamination in murals and visitor walking could increase this hazard. In order to study the impact of visitors walking on the air flow and the distribution of BPs in the typical tomb chambers, the k-ε and Lagrangian discrete phase model were adopted. The walking visitor was described by the dynamic mesh, and the concentration of BPs in the simulation was verified by experimental sampling. The distribution and migration mechanism of contamination in the chamber were dynamically analyzed. The results indicate that the denser vortex generated when a visitor was walking, and the concentration of BPs changed obviously. Therefore, the number of BPs deposited on some precious murals increased and the contamination location shifted in the direction of visitor walking. In addition, the deposition time of BPs was lagging which would cause potential risk. This research can provide scientific basis for reducing murals contamination during visitor visiting and a reference for the maintenance of ancient buildings.

Study of the Effects of Shearer’ Kinematic Parameters on on-Way Distribution of Dust on Coal Face

2011 ◽  
Vol 127 ◽  
pp. 400-405
Author(s):  
Xiao Huo Li ◽  
Shu Ming Liu ◽  
Zhi Long Huang ◽  
Wei Du
Keyword(s):  
Rotational Speed ◽  
Dust Concentration ◽  
Discrete Phase Model ◽  
Kinematic Parameters ◽  
Coal Face ◽  
Two Phase ◽  
Concentration Maximum ◽  
Discrete Phase ◽  
And Migration ◽  
Kinematical Parameters

In order to research the effects of shearer’ kinematical parameters on on-way distribution of dust on coal face, according to the theory of suspension gas-solid two-phase flow and the theory of cutting dust formation, mathematical model of on-way dust concentration was established, methods of determining parameters were given, dust migration was simulated by using the discrete phase model (DPM) in FLUENT, on-way distribution regularity of dust was found. According to calculation of the quantity of cutting dust at different hauling speed and different rotational speed of drum, dust migration was simulated and migration regularity was showed as follows: dust concentration of every point on a coal face increased as hauling speed decreased or rotational speed increased. In addition, with rotational speed increased, the position of concentration maximum moved a little along downwind.

Experimental and Numerical Investigation on the Erosion Wear of an Impact Sprinkler

2014 ◽  
Author(s):  
Yuncheng Xu ◽  
Guan Lin ◽  
Haijun Yan
Keyword(s):  
Internal Flow ◽  
Internal Surface ◽  
Sprinkler Irrigation ◽  
Sediment Concentration ◽  
Western China ◽  
Erosion Wear ◽  
Discrete Phase Model ◽  
Discrete Phase ◽  
The Cost ◽  
The Impact

In the middle and western China, agricultural irrigation water often contains a high sediment concentration. In order to save the cost, no filtration devices are required for sprinkler irrigation, which results in the wear of sprinkling irrigation equipment, especially on the nozzle. In this study, experiments on the erosion wear of an impact sprinkler (PY1-20sh with aluminum alloy nozzles) were conducted under different conditions of sediment concentration and erosion time. Using the experimental data as boundary conditions, numerical simulations based on the discrete phase model (DPM) were conducted to analyze the wear of the internal surface of the sprinkler’s full flow passage. Based on both experimental and numerical results, the erosion wear mechanism of the internal flow surface was revealed, and prediction model of the nozzle’s wear rate was established, providing the technical guidance for design and operation of the impact sprinkler.

Based Fluent Study of Rotary Stream for Sand Reclamation Equipment

2015 ◽  
Vol 741 ◽  
pp. 486-489
Author(s):  
Wen Long Lu ◽  
Shan Li ◽  
Ying Luo ◽  
Qiang Chen
Keyword(s):  
Numerical Simulation ◽  
Kinetic Energy ◽  
Basic Structure ◽  
Velocity Control ◽  
Turbulent Model ◽  
Discrete Phase Model ◽  
Discrete Phase ◽  
Sand Movement ◽  
The Impact ◽  
Movement Tracking

The basic structure and principles of rotary stream for sand reclamation device will be introduction. According to the principle of renewable rotary stream for sand reclamation equipment, combination with Fluent numerical simulation model to construct the old sand regeneration process. And according to the impact velocity control problem for sand, using discrete phase model and turbulent model, the sand movement tracking and turbulent kinetic energy and the blowpipe of equipment were analyzed, finally puts forward some suggestions for improvement.

scholarly journals Migration and Welfare State: the Coherence Between Welfare State, Migratory Regimes and Migration Flows

2018 ◽  
Vol 29 (4) ◽  
Author(s):  
Ingrida Gečienė-Janulionė
Keyword(s):  
Welfare State ◽  
Welfare Regimes ◽  
Migration Flows ◽  
And Migration ◽  
High Level ◽  
Welfare State Regimes ◽  
The Impact ◽  
Migration Regimes ◽  
The Welfare State

This article examines the relationship between different types of the welfare state, migration regimes and changes in migration flows. It discusses the implications and limitations of the ‘welfare magnet’ theory explaining the impact of welfare regimes on migration flows as well as the interactions between migration regimes and welfare state situations. Also the impact of different welfare state regimes on migration flows is presented there. In Lithuania, as well as in other countries with a high level of emigration, the relations between the welfare state, migration regimes and migration are not fully explored; therefore, the article also presents the case study of Lithuania in order to provide guidelines for further studies in this field.

“To the Ends of the Earth”: Mission, Migration and the Impact of African-led Pentecostal Churches in the European Diaspora

2012 ◽  
Vol 29 (1) ◽  
pp. 23-44 ◽  
Author(s):  
J. Kwabena Asamoah-Gyadu
Keyword(s):  
Religious Communities ◽  
Conversion Narratives ◽  
Immigrant Churches ◽  
New Type ◽  
Pentecostal Churches ◽  
And Migration ◽  
Born Again ◽  
The Impact ◽  
World Mission

Abstract The rise of immigrant churches and African-led churches in the Diaspora is one of the most important developments to occur in world mission at the end of the 20th century. Most of these churches are made up of Africans who felt left out in the historic churches of the West. A number of these are of Pentecostal/charismatic persuasion and have developed into some of the most dynamic religious communities in the countries where they exist. Additionally, a new type of African-led church has emerged in the diaspora in Europe. This article is a case study of two well-known African diaspora mega-churches in Europe, the Church of the Embassy of the Blessed Kingdom of God for all Nations based in Kyiv, Ukraine led by Sunday Adelaja, and the London-based Kingsway International Christian Center led by Matthew Ashimolowo. Using the conversion narratives of the born-again experience and the subsequent redemptive uplifts that people testify to have experienced through these churches, the article discusses the importance of these developments within the context of mission and migration in the diaspora.

scholarly journals Numerical Analysis of RTD Curves and Inclusions Removal in a Multi-Strand Asymmetric Tundish with Different Configuration of Impact Pad

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 849
Author(s):  
Markéta Tkadlečková ◽  
Josef Walek ◽  
Karel Michalek ◽  
Tomáš Huczala
Keyword(s):  
Dead Volume ◽  
Discrete Phase Model ◽  
Inclusion Removal ◽  
Ansys Fluent ◽  
Assembly Method ◽  
Cut Cell ◽  
Computational Mesh ◽  
Discrete Phase ◽  
Steel Flow ◽  
The Impact

To effectively remove non-metallic inclusions from the steel during the flowing in a five-strand asymmetric tundish, the novel configuration of the impact pad was developed. For analysis, complex numerical modelling in the programme ANSYS Fluent was used. The Lagrangian Discrete Phase Model of inclusion tracking was applied. The distribution of inclusions, with sizes ranging from 2 µm to 100 µm and density from 2500 to 3500 kg·m−3, was considered only through the shroud tube. The residence time distribution (RTD) curves and inclusion removal efficiency were used for evaluation of steady state steel flow character depending on internal configuration of a tundish with an impact pad in two design modifications (Modification 1—M1, Modification 2—M2). The preliminary results showed that in the case of asymmetric geometry plays a role the computational mesh independency. The assembly method with cut cell approach was satisfactory even when the tundish geometry was changed. The RTD curves with an M1 showed a huge dead volume in the tundish. In the case with an M2, the RTD curves are more or less uniform for all casting strands, and the removal of inclusions to slag increased from about 55% up to 70% in comparison with M1.

Velocity and Sludge Distribution Simulation of the Aerobic Tank of Step-Feed A/O Process

2014 ◽  
Vol 886 ◽  
pp. 323-326
Author(s):  
Shen Zhao ◽  
Xue Yi You ◽  
Sheng Jun Liu ◽  
Yu Huang ◽  
Feng Shi ◽  
...  
Keyword(s):  
Vertical Direction ◽  
Bottom Layer ◽  
Wastewater Sludge ◽  
Space Distribution ◽  
Discrete Phase Model ◽  
Two Phase ◽  
Discrete Phase ◽  
The Mean ◽  
Aeration Process ◽  
The Impact

The velocity and sludge distribution in the aerobic tank of step-feed A/O process were simulated by the two-phase flow model. The aeration process was simulated by the discrete phase model and the influence of the aeration on the sludge distribution was studied. The space distribution of the wastewater-sludge-bubble in the aerobic tank was determined. The results showed that the sludge age is hard to be control led as the eddies in the aerobic tank have a strong influence on the sludge retention time. The impact of the aeration on the mean sludge concentration is neglectable. The uniformity of sludge distribution along the vertical direction and the sludge sedimentation on the bottom layer are improved by the process of aeration. The results have great theoretical significance and guidance for the optimal design of the aerobic tank of step-feed A/O process.

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