scholarly journals CFD analysis on the effect of temperature on gas distribution in indoor environment

2021 ◽  
Vol 2107 (1) ◽  
pp. 012054
Author(s):  
Z H Mohd Juffry ◽  
K Kamarudin ◽  
A H Adom ◽  
A N Abdullah ◽  
I N Ismail
Keyword(s):  
Indoor Environment ◽  
Ventilation System ◽  
Three Dimensional ◽  
Effect Of Temperature ◽  
Smoke Detector ◽  
Gas Distribution ◽  
Gas Dispersion ◽  
Ambient Temperatures ◽  
Different Temperatures ◽  
The Way

Abstract There are times when people are required to spend time indoors, especially due to unhealthy outdoor air quality as well during a pandemic when lockdowns are imposed. However, spending time indoors can also at times be dangerous due to the release of harmful gasses if left unchecked. This has very much to do with many parameters, among which is the indoor environment and its ventilation. The latter is affected by the way gases distribute inside the building. It is influenced by many factors such as temperature, wind, air circulation, and also ventilation system itself. The knowledge on how the gases spread in different conditions within the indoor environment can be utilized in many applications such as improving the smoke detector safety system and identifying as well as predicting the potential risks. This paper presents the investigation of the effect of different temperatures on gas distribution in an indoor environment. A three-dimensional simulation was performed of different temperature gas released in a closed room that has different ambient temperatures. The effect of temperature on the gas dispersion was observed. The results revealed that there is a significant effect of temperature on the way gas spread in the indoor environment support by the theoretical knowledge on the relationship between temperature and gas in the gas law.

Mechanical behavior and failure mechanism of three-dimensional braided composites at different temperatures

2020 ◽  
Vol 62 (6) ◽  
pp. 612-616
Author(s):  
Weimin Jiang ◽  
Junmeng Zhou ◽  
Jie Mei ◽  
Jiayi Liu ◽  
Wei Huang
Keyword(s):  
Failure Mechanism ◽  
Composite Laminates ◽  
Room Temperature ◽  
Three Dimensional ◽  
Compressive Modulus ◽  
Effect Of Temperature ◽  
Resin Matrix ◽  
Stress Strain ◽  
Braided Composite ◽  
Different Temperatures

AbstractThis investigation explored the effect of temperature on the compressive behaviors and failure mechanism of three dimensional (3D) carbon/ epoxy five-directional braided composite laminates. The compression tests of 3D braided composite laminates were performed at six different temperatures, which are 20 °C (room temperature), 50 °C, 70 °C, 90 °C, 110 °C and 130 °C, respectively. Then the effect of temperature on the failure mechanism, stress-strain curves, compressive modulus and strength of the composite laminates were analyzed and compared to that at room temperature. The results have shown that the temperature had a significant effect on the compressive properties and failure mechanism of 3D braided composite laminates. At 20 °C and 50 °C, the 3D braided composite laminates failed by shear fracture, and the stress-strain curves exhibited obvious linear elasticity and a brittle failure feature. While, at higher temperatures (70 °C, 90 °C, 110 °C and 130 °C), it was found that the specimens exhibited obvious plastic kinking, and the stress-strain curves exhibited obvious non-linear trend and a plastic failure feature due to the epoxy resin matrix becoming softened and plastic. The compressive modulus and strength decreased as temperature increased. The compressive modulus and strength decreased by 92.3 % and 93.8 % when the temperature increased from 20 °C to 130 °C.

Effect of temperature on structure, morphology and crystallinity of PVDF nanofibers via electrospinning

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Fenglin Huang ◽  
Qufu Wei ◽  
Jiaxi Wang ◽  
Yibing Cai ◽  
Yubo Huang
Keyword(s):  
Thermal Properties ◽  
Ambient Temperature ◽  
Vinylidene Fluoride ◽  
Effect Of Temperature ◽  
Scanning Calorimetry ◽  
Ambient Temperatures ◽  
Force Microscopy ◽  
Poly Vinylidene Fluoride ◽  
Different Temperatures ◽  
Surface Morphologies

Abstract Influence of temperature on morphology, structure and crystallinity of Poly (vinylidene fluoride) (PVDF) nanofibers was investigated in this study. The Wehilmy technique and viscosity testing apparatus were used to evaluate the surface tension and viscosity of electrospun solutions at various ambient temperatures. Surface morphologies and diameters of nanofibers were examined by Field-emission Scanning Electron Microscopy (FE-SEM) and atomic force microscopy (AFM). It was found that the surface morphologies were obviously affected by ambient temperature. This dependence was attributed to the change of the properties of Poly (vinylidence fluoride) solutions with temperature. The thermal properties and crystal structures of the PVDF nanofibers electrospun at different temperatures were also studied by differential scanning calorimetry (DSC), and Xray diffraction (XRD). The results revealed that the crystallinity and thermal properties were improved by increasing the ambient temperature during electrospinning

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

scholarly journals Effect of temperature, CO2 and O2 on motility and mobility of Anisakidae larvae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël
Keyword(s):  
Enzymatic Digestion ◽  
Infected Fish ◽  
Effect Of Temperature ◽  
Video Recordings ◽  
Different Temperatures ◽  
Semi Solid ◽  
Zoonotic Parasites ◽  
The Impact ◽  
Phosphate Buffered Saline

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.

scholarly journals Effect of Temperature during Drying and Storage of Dried Figs on Growth, Gene Expression and Aflatoxin Production

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 134
Author(s):  
Ana Isabel Galván ◽  
Alicia Rodríguez ◽  
Alberto Martín ◽  
Manuel Joaquín Serradilla ◽  
Ana Martínez-Dorado ◽  
...  
Keyword(s):  
Gene Expression ◽  
Aflatoxin Production ◽  
Effect Of Temperature ◽  
Mycotoxin Production ◽  
Industrial Processing ◽  
Factors Associated ◽  
Different Temperatures ◽  
Major Producer ◽  
Main Factors ◽  
And Storage

Dried fig is susceptible to infection by Aspergillus flavus, the major producer of the carcinogenic mycotoxins. This fruit may be contaminated by the fungus throughout the entire chain production, especially during natural sun-drying, post-harvest, industrial processing, storage, and fruit retailing. Correct management of such critical stages is necessary to prevent mould growth and mycotoxin accumulation, with temperature being one of the main factors associated with these problems. The effect of different temperatures (5, 16, 25, 30, and 37 °C) related to dried-fig processing on growth, one of the regulatory genes of aflatoxin pathway (aflR) and mycotoxin production by A. flavus, was assessed. Firstly, growth and aflatoxin production of 11 A. flavus strains were checked before selecting two strains (M30 and M144) for in-depth studies. Findings showed that there were enormous differences in aflatoxin amounts and related-gene expression between the two selected strains. Based on the results, mild temperatures, and changes in temperature during drying and storage of dried figs should be avoided. Drying should be conducted at temperatures >30 °C and close to 37 °C, while industry processing, storage, and retailing of dried figs are advisable to perform at refrigeration temperatures (<10 °C) to avoid mycotoxin production.

A Computational Analysis of Flow Field in Twin-Track Subway Tunnel to Improve Air Quality

2013 ◽  
Vol 319 ◽  
pp. 599-604
Author(s):  
Makhsuda Juraeva ◽  
Kyung Jin Ryu ◽  
Sang Hyun Jeong ◽  
Dong Joo Song
Keyword(s):  
Air Quality ◽  
Computational Model ◽  
Stokes Equations ◽  
Ventilation System ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Subway Tunnel ◽  
Air Supply ◽  
And Performance

A computational model of existing Seoul subway tunnelwas analyzed in this research. The computational model was comprised of one natural ventilationshaft, two mechanical ventilationshafts, one mechanical airsupply, a twin-track tunnel, and a train. Understanding the flow pattern of the train-induced airflow in the tunnel was necessary to improve ventilation performance. The research objective wasto improve the air quality in the tunnel by investigating train-induced airflow in the twin-track subway tunnel numerically. The numerical analysis characterized the aerodynamic behavior and performance of the ventilation system by solving three-dimensional turbulent Reynolds-averaged Navier-Stokes equations. ANSYS CFX software was used for the computations. The ventilation and aerodynamic characteristics in the tunnel were investigated by analyzing the mass flowrateat the exits of the ventilation mechanicalshafts. As the train passed the mechanical ventilation shafts, the amount of discharged-air in the ventilationshafts decreased rapidly. The air at the exits of the ventilation shafts was gradually recovered with time, after the train passed the ventilation shafts. The developed mechanical air-supply for discharging dusty air and supplying clean airwas investigated.The computational results showed that the developed mechanical air-supplycould improve the air quality in the tunnel.

Remarks on marine and continental biogeography: an areographical viewpoint

1994 ◽  
Vol 343 (1303) ◽  
pp. 71-78 ◽  
Keyword(s):  
Species Richness ◽  
Baltic Sea ◽  
Three Dimensional ◽  
Wide Spread ◽  
The Baltic Sea ◽  
Biogeographical Regions ◽  
The Baltic ◽  
The Way

Differences and similarities in the way marine and continental organisms occupy space are briefly reviewed. Among them, the ‘peninsula effect’ (the decline of species richness with distance from the source) is compared with the ‘bay effect’. Two cases, corals in Mochima Bay, Venezuela and fishes in the Baltic Sea, are presented as examples. The facts that the world’s oceans are larger, continuous and three-dimensional, with fewer evident geographical barriers than there are on land, explain why marine biogeographical regions are less welldefined and geographical ranges of marine taxa more wide-spread. I his generalization has, however, been questioned following recent findings of extremely rich and highly endemic benthic faunas. This problem is discussed using an index of cosmopolitanism to compare terrestrial and marine biotas.

Computational Modeling of Particulate Pollutant Transport in a Ventilated Room in the Presence of Two Heated Breathing and Rotating Manikins

2017 ◽  
Author(s):  
Seyed Ali Keshavarz ◽  
Mazyar Salmanzadeh ◽  
Goodarz Ahmadi
Keyword(s):  
Air Quality ◽  
Computational Modeling ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Rotational Motion ◽  
Indoor Environment ◽  
Ventilation System ◽  
Thermal Plume ◽  
Displacement Ventilation ◽  
Simulation Results

Recently, attention has been given to indoor air quality due to its serious health concerns. Clearly the dispersion of pollutant is directly affected by the airflow patterns. The airflow in indoor environment is the results of a combination of several factors. In the present study, the effects of thermal plume and respiration on the indoor air quality in a ventilated cubicle were investigated using an unsteady computational modeling approach. The person-to-person contaminant transports in a ventilated room with mixing and displacement ventilation systems were studied. The effects of rotational motion of the heated manikins were also analyzed. Simulation results showed that in the cases which rotational motion was included, the human thermal plume and associated particle transport were significantly distorted. The distortion was more noticeable for the displacement ventilation system. Also it was found that the displacement ventilation system lowered the risk of person-to-person transmission in an office space in comparison with the mixing ventilation system. On the other hand the mixing system was shown to be more effective compared to the displacement ventilation in removing the particles and pollutant that entered the room through the inlet air diffuser.

Sign in / Sign up

Export Citation Format

Share Document