scholarly journals The effect of straight chimney temperature on pollutant dispersion

2021 ◽  
Vol 234 ◽  
pp. 00009
Author(s):  
Fida Zair ◽  
Mhamed Mouqallid ◽  
El houssine Chatri
Keyword(s):  
Air Pollution ◽  
Wind Speed ◽  
Energy Conservation ◽  
Pollutant Dispersion ◽  
Ansys Fluent ◽  
First Case ◽  
Air Stream ◽  
Two Parameters ◽  
Volume Method

Air pollution is considered one of the most important contemporary problems that threaten a person's life and environment. Among the major sources of air pollution are pollutants emitted from smokestacks. The objective of this work is to numerically study the dispersion of a pollutant ejected from a chimney into an air stream. The mass, momentum and energy conservation equations are solved using the finite volume method (MFV) and numerical simulations are performed using Ansys Fluent CFD software. Two case studies were discussed: The first case study is to study the influence of the direction of the wind speed and in the last case study, the temperature evolution on the dispersion of the ejected plume particles. The study demonstrated the extent of the dispersion in relation to these two parameters. The results obtained confirm the need to improve filtering systems in order to reduce the risks attributed to discharges and to propose solutions to manage the effect of these discharges on the environmental population.

Case Study of Nanjing Inner Ring on Air Pollution Dispersion from Roadway Tunnel Portals

2012 ◽  
Vol 610-613 ◽  
pp. 1895-1900 ◽  
Author(s):  
Shu Jiang Miao ◽  
Da Fang Fu
Keyword(s):  
Air Pollution ◽  
Pollutant Dispersion ◽  
Air Pollutant ◽  
Urban Traffic ◽  
Lagrangian Model ◽  
Pollution Dispersion ◽  
Piecewise Function ◽  
Air Pollutant Dispersion ◽  
Air Pollution Dispersion

The tunnel module of a rather simple Lagrangian model GRAL (Grazer Langrange model) has been chosen to study air pollutant dispersion around tunnel portals in Nanjing inner ring. Two points have been made to popularize GRAL3.5TM (the tunnel module of a Lagrangian model GRAL; the update was in May 2003) and assure it more suitable for the actual situations in Nanjing. One is to derive a piecewise function of the intermediate parameter ‘stiffness’. Another is to take Romberg NOx-NO2 scheme into account. After these 2 works on GRAL3.5TM, NO2 dispersion from portals of all the 6 tunnels in Nanjing inner ring has been simulated. The importance of limiting urban traffic volume to control air quality around tunnel portals and roadways has been emphasized.

scholarly journals Time Series Modeling of Air Pollution and Its Association with Season and Climate Variables in Istanbul, Turkey

2020 ◽  
Author(s):  
hazem al-najjar ◽  
Nadia Al-Rousan ◽  
Ismail A. Elhaty
Keyword(s):  
Air Pollution ◽  
Time Series ◽  
Feature Selection ◽  
Wind Speed ◽  
Air Pollutants ◽  
Time Series Modeling ◽  
Climate Variables ◽  
Different Seasons ◽  
The Impact

Abstract Air pollution depends on seasons, wind speed, temperature, wind direction and air pressure. The effect of different seasons on air pollution is not fully addressed in the reported works. The current study investigated the impact of season on air pollutants including SO2, PM10, NO, NOX, and O3 using NARX method. In the applied methodology, a feature selection was used with each pollutant to find the most important season(s). Afterward, six models are designed based on the feature selection to show the impact of seasons in finding the concentration of pollutants. A case study is conducted on Esenyurt which is one of the most populated and industrialized places in Istanbul to validate the proposed framework. The performance of using all of the designed models with different pollutants showed that using season effect led to improving the performance of predictor and generating high R2 and low error functions.

Lava dome morphology inferred from numerical modelling

2020 ◽  
Vol 223 (3) ◽  
pp. 1597-1609
Author(s):  
Igor Tsepelev ◽  
Alik Ismail-Zadeh ◽  
Oleg Melnik
Keyword(s):  
Lava Dome ◽  
Volume Fraction ◽  
Discharge Rate ◽  
Ansys Fluent ◽  
Rate Dependent ◽  
Lava Domes ◽  
Two Parameters ◽  
Volume Method ◽  
Crystal Content ◽  
Lava Viscosity

SUMMARY Lava domes form when highly viscous magmas erupt on the surface. Several types of lava dome morphology can be distinguished depending on the flow rate and the rheology of magma. Here, we develop a 2-D axisymmetric model of magma extrusion on the surface and lava dome evolution and analyse the dome morphology using a finite-volume method implemented in Ansys Fluent software. The magma/lava viscosity depends on the volume fraction of crystals and temperature. We show that the morphology of domes is influenced by two parameters: the characteristic time of crystal content growth (CCGT) and the discharge rate (DR). At smaller values of the CCGTs, that is, at rapid lava crystallization, obelisk-shaped structures develop at low DRs and pancake-shaped structures at high DRs; at longer CCGTs, lava domes feature lobe- to pancake-shaped structures. A thick carapace of about 70 per cent crystal content evolves at smaller CCGTs. We demonstrate that cooling does not play the essential role during a lava dome emplacement, because the thermal thickness of the evolving carapace remains small in comparison with the dome's height. A transition from the endogenic to exogenic regime of the lava dome growth occurs after a rapid increase in the DR. A strain-rate-dependent lava viscosity leads to a more confined dome, but the influence of this viscosity on the dome morphology is not well pronounced. The model results can be used in assessments of the rates of magma extrusion, the lava viscosity and the morphology of active lava domes..

scholarly journals Characterization of the Average Wind Speed in the Municipaly of Teresina-PI

2020 ◽  
pp. 94-101
Author(s):  
Raimundo Mainar de Medeiros ◽  
Moacyr Cunha Filho ◽  
Manoel Vieira de França ◽  
Romildo Morant de Holanda ◽  
Victor Casimiro Piscoya ◽  
...  
Keyword(s):  
Wind Speed ◽  
Pollutant Dispersion ◽  
Accurate Information ◽  
Average Wind Speed ◽  
Air Masses ◽  
Wind Speeds ◽  
Average Wind ◽  
Different Temperatures ◽  
Two Parameters

The winds are of fundamental importance in the terrestrial dynamics; Represent one of the main elements influencing various climate phenomena such as soil erosion, pollutant dispersion, seed transport and generation of wind energy. The characterization of the wind at any point of the atmosphere takes two parameters: Speed and direction, which are instantaneous quantities because they depend on conditions such as atmospheric pressure gradient originating displacement of air masses at different temperatures. Accurate information on wind speed is important as it plays a significant role in the application efficiency. Considering the importance of understanding the behavior of the wind, this work, was aimed to characterize the average wind speeds for the city of Teresina, located in the state of Piauí, Brazil. We used 1976 to 2019 data on wind speed of 10 meters height obtained fromthe records of the conventional meteorological station of the National Institute of Meteorology (INMET). The highest wind speed is in July to November with speed ranging from 1.6 to 1.8 m/s and the lowest wind speeds are centered in the months from December to April with oscillation 1.3 to 1.5 m.s-1.

scholarly journals SEBARAN PARTIKULAT (PM10) PADA MUSIM KEMARAU DI KABUPATEN TANGERANG DAN SEKITARNYA

2014 ◽  
Vol 15 (2) ◽  
pp. 89
Author(s):  
Khariza Dwi Sepriani ◽  
Ana Turyanti ◽  
Mahally Kudsy
Keyword(s):  
Air Pollution ◽  
Wind Speed ◽  
Anthropogenic Activities ◽  
Pollutant Dispersion ◽  
Industrial Area ◽  
Dry Season ◽  
Air Pollutant ◽  
Transportation Sector ◽  
Forecast Result ◽  
Surrounding Areas

Intisari   Pencemaran udara yang bersumber dari aktivitas antropogenik dewasa ini menjadi semakin meningkat seiring dengan berkembangnya sektor industri dan transportasi. Kabupaten Tangerang dan sekitarnya merupakan daerah industri besar di Indonesia, sehingga masyarakat di wilayah tersebut memiliki potensi terpapar pencemar udara yang tinggi. Salah satunya adalah partikulat.  Sebaran partikulat dipengaruhi oleh beberapa hal diantaranya jumlah sumber emisi, serta faktor meteorologi terutama angin. Pemantauan sebaran pencemar perlu dilakukan sebagai pertimbangan untuk mengambil kebijakan terkait masalah lingkungan. Namun pemantauan pencemar terkendala oleh biaya yang besar dan ketersediaan alat di lapangan, sehingga untuk memudahkan melakukan pemantauan digunakan model sebaran pencemar. Penelitian ini bertujuan untuk mengetahui arah sebaran pencemar PM10 di wilayah Kabupaten Tangerang dan sekitarnya berdasarkan arah angin pada musim kemarau. Metode dalam penelitian ini menggunakan model Chimere yang dapat menghasilkan prakiraan pencemar udara harian, termasuk aerosol dan polutan lain. Hasil analisis menunjukkan konsentrasi PM10 tinggi di daerah sekitar Kotamadya Tangerang. Banyaknya industri dan padatnya kendaraan bermotor serta angin dominan yang menuju timur pada musim kemarau menyebabkan konsentrasi PM10 di Kota Tangerang Selatan hingga Kota Tangerang lebih tinggi daripada di sekitarnya, yakni mencapai 26-28 μg m-3. Nilai korelasi antara kecepatan angin dan konsentrasi partikulat sebesar -0.46 menunjukkan kecepatan angin cukup mempengaruhi tingkat konsentrasi PM10.   Abstract  Air pollution originating from anthropogenic activities nowadays be increased along with industry development and transportation sector. Tangerang District and its surrounding areas are a large industrial area in Indonesia, so people in the region have a high potential for exposure to air pollutant. Particulate is one of the pollutions. Monitoring the pollutant dispersion is necessary to be conducted as a consideration to take a policy related to environmental issues. However, pollutant monitoring constrained by cost and availability of tools in the field, so the model is used to make pollutant monitoring easier. This study aims to determine the direction of PM10 pollutant dispersion in Tangerang  and the surrounding area based the dominant wind direction in the dry season. The method in this study uses Chimere model that can generate daily air pollution forecast. Result shows high PM10 concentration around Tangerang City. High number of industries and vehicles and also the dominant winds eastward in the dry season led to a concentration of PM10 in Tangerang City until South Tangerang City higher than around, namely reached 26-28 μg m-3. Correlation value between wind speed and particulate concentration is -0.46 indicated that the wind speed has considerable influence the level of PM10 concentrations.

Failure Analysis Case Study of a 1.5 Meter Space Flex Harness

2017 ◽  
Author(s):  
Erick Kim ◽  
Kamjou Mansour ◽  
Gil Garteiz ◽  
Javeck Verdugo ◽  
Ryan Ross ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Failure Modes ◽  
Field Of View ◽  
Area Of Interest ◽  
Air Stream ◽  
Novel Method ◽  
Temperature Controlled ◽  
Non Destructive ◽  
Failure Site

Abstract This paper presents the failure analysis on a 1.5m flex harness for a space flight instrument that exhibited two failure modes: global isolation resistances between all adjacent traces measured tens of milliohm and lower resistance on the order of 1 kiloohm was observed on several pins. It shows a novel method using a temperature controlled air stream while monitoring isolation resistance to identify a general area of interest of a low isolation resistance failure. The paper explains how isolation resistance measurements were taken and details the steps taken in both destructive and non-destructive analyses. In theory, infrared hotspot could have been completed along the length of the flex harness to locate the failure site. However, with a field of view of approximately 5 x 5 cm, this technique would have been time prohibitive.

Two mechanisms for accelerated diffusion of COVID-19 outbreaks in regions with high intensity of population and polluting industrialization: the air pollution-to-human and human-to-human transmission dynamics (Preprint)

2020 ◽  
Author(s):  
Mario Coccia
Keyword(s):  
Air Pollution ◽  
Wind Speed ◽  
Critical Role ◽  
Meteorological Condition ◽  
Meteorological Conditions ◽  
Lessons Learned ◽  
Transmission Dynamics ◽  
Critical Threshold ◽  
Viral Infectivity ◽  
Low Wind Speed

BACKGROUND Coronavirus disease 2019 (COVID-19) is viral infection that generates a severe acute respiratory syndrome with serious pneumonia that may result in progressive respiratory failure and death. OBJECTIVE This study has two goals. The first is to explain the main factors determining the diffusion of COVID-19 that is generating a high level of deaths. The second is to suggest a strategy to cope with future epidemic threats with of accelerated viral infectivity in society. METHODS Correlation and regression analyses on on data of N=55 Italian province capitals, and data of infected individuals at as of April 2020. RESULTS The main results are: o The accelerate and vast diffusion of COVID-19 in North Italy has a high association with air pollution. o Hinterland cities have average days of exceeding the limits set for PM10 (particulate matter 10 micrometers or less in diameter) equal to 80 days, and an average number of infected more than 2,000 individuals as of April 1st, 2020, coastal cities have days of exceeding the limits set for PM10 equal to 60 days and have about 700 infected in average. o Cities that average number of 125 days exceeding the limits set for PM10, last year, they have an average number of infected individual higher than 3,200 units, whereas cities having less than 100 days (average number of 48 days) exceeding the limits set for PM10, they have an average number of about 900 infected individuals. o The results reveal that accelerated transmission dynamics of COVID-19 in specific environments is due to two mechanisms given by: air pollution-to-human transmission and human-to-human transmission; in particular, the mechanisms of air pollution-to-human transmission play a critical role rather than human-to-human transmission. o The finding here suggests that to minimize future epidemic similar to COVID-19, the max number of days per year in which cities can exceed the limits set for PM10 or for ozone, considering their meteorological condition, is less than 50 days. After this critical threshold, the analytical output here suggests that environmental inconsistencies because of the combination between air pollution and meteorological conditions (with high moisture%, low wind speed and fog) trigger a take-off of viral infectivity (accelerated epidemic diffusion) with damages for health of population, economy and society. CONCLUSIONS Considering the complex interaction between air pollution, meteorological conditions and biological characteristics of viral infectivity, lessons learned for COVID-19 have to be applied for a proactive socioeconomic strategy to cope with future epidemics, especially an environmental policy based on reduction of air pollution mainly in hinterland zones of countries, having low wind speed, high percentage of moisture and fog that create an environment that can damage immune system of people and foster a fast transmission of viral infectivity similar to the COVID-19. CLINICALTRIAL not applicable

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