Influence of Temperature and Relative Humidity on Perm-Selectivity of PET Packaging Film

The main feature of this article is the investigation on the influence of temperature, relative humidity, film thickness on permeability of PET packaging film, the analysis of perm-selectivity of the packaging films for oxygen gas and carbon dioxide gas, and the evaluation on experimental formulas of water vapor, O2 and CO2 gas permeating rates on the basis of gas molecular osmotic reaction kinetics and regression analysis. The comparison between experimental studies and calculation indicates that: (1) with increment of ambient temperature water vapor, O2 and CO2 permeating rate of PET films and PET/Al film also rise, and the logarithm of water vapor, O2 and CO2 gas permeating rates has linear relation with the reciprocal of thermodynamic temperature, and (2) the influence of relative humidity on water vapor permeating rate of PET film with thickness 12µm is the least, and that of PET film with thickness 20µm and PET/Al film with thickness 18µm is a little obvious. (3) The PET films hold remarkable perm-selectivity for O2 and CO2 gas, and CO2 gas permeating rate is about two times of O2 gas, yet O2 and CO2 gas permeating rates of PET/Al film are both very low and have small difference, so the PET/Al film has better barrier performance than the PET film.

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Pengaruh Suhu dan Kelembaban Terhadap Rasio Kelembaban dan Entalpi (Studi Kasus: Gedung UNIFA Makassar)

LOSARI : Jurnal Arsitektur Kota dan Pemukiman ◽

10.33096/losari.v6i2.307 ◽

2021 ◽

pp. 102-114

Author(s):

Ahmad Nadhil Edar

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Experimental Studies ◽

Well Being ◽

Specific Humidity ◽

Unit Mass ◽

Specific Enthalpy ◽

Humidity Ratio ◽

Total Enthalpy ◽

Dry Air

Temperature affects humidity. The interaction of temperature and humidity also directly affects the health and well-being of humans. The relative humidity (RH) of the air is an indication of how much water vapor is in the air at a particular temperature compared with how much water vapor the air could actually hold at that temperature. Air at 100 % relative humidity holds the maximum amount of water possible at that particular temperature and is said to be saturated. Therefore, air at 50% relative humidity, regardless of temperature, is holding half of its total possible water capacity. In essence, cold air cannot hold as much water vapor as warm air. In a closed environment such as a display case, there will be a fixed amount of water vapor, referred to as the absolute humidity. If the temperature inside the case falls then the relative humidity will rise. If the temperature rises the relative humidity will fall. Such changes in relative humidity could be caused by many factors including direct sunlight, spotlights and air-conditioning failures. Research carried out by experimental studies that we can get the humidity ratio and specific enthalpy in a kind of rooms either using The Psychrometric Chart and The formula. The specific humidity or humidity ratio of an air sample is the ratio of the weight of water vapor contained in the sample compared to the weight of the dry air in the same sample. Enthalpy is the amount of heat (energy) in the air per unit mass. Enthalpy is the total amount of energy present in the air, both from air and water vapor contained therein. And, Specific enthalpy of moist air is defined as the total enthalpy of the dry air and the water vapor mixture - per unit mass of dry air. Keywords: Temperature; Relative Humidity; Humidity Ratio; Specific Enthalpy.

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Single-footprint retrievals of temperature, water vapor and cloud properties from AIRS

10.5194/amt-2017-197 ◽

2017 ◽

Cited By ~ 1

Author(s):

Fredrick W. Irion ◽

Brian H. Kahn ◽

Mathias M. Schreier ◽

Eric J. Fetzer ◽

Evan Fishbein ◽

...

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Optimal Estimation ◽

Horizontal Resolution ◽

Forward Model ◽

Retrieval Algorithm ◽

Cloud Particle ◽

Cloud Data ◽

Level 2 ◽

Temperature Water

Abstract. Single-footprint Atmospheric Infrared Sounder spectra are used in an optimal estimation-based algorithm (AIRS-OE) for simultaneous retrieval of atmospheric temperature, water vapor, surface temperature, cloud-top temperature, effective cloud optical depth and effective cloud particle radius. In a departure from currently operational AIRS retrievals (AIRS-V6), cloud scattering and absorption are in the radiative transfer forward model, and Level 1b AIRS thermal infrared data are used directly rather than Level 2 cloud-cleared spectra. Coincident MODIS Level 2 cloud data are used for cloud a priori. Using Level 1b spectra improves the horizontal resolution of the AIRS retrieval from ~ 45 km to ~ 13.5 km at nadir, but as microwave data are not used, retrieval is not made at altitudes below thick clouds. An outline of the AIRS-OE retrieval procedure and information content analysis is presented. Initial comparison of AIRS-OE to AIRS-V6 results show increased horizontal detail in the water vapor and relative humidity fields in the free troposphere above clouds. Comparisions of temperature, water vapor and relative humidity profiles against coincident radiosondes show good agreement. Future improvements to the retrieval algorithm, and to the forward model in particular, are discussed.

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Single-footprint retrievals of temperature, water vapor and cloud properties from AIRS

Atmospheric Measurement Techniques ◽

10.5194/amt-11-971-2018 ◽

2018 ◽

Vol 11 (2) ◽

pp. 971-995 ◽

Cited By ~ 15

Author(s):

Fredrick W. Irion ◽

Brian H. Kahn ◽

Mathias M. Schreier ◽

Eric J. Fetzer ◽

Evan Fishbein ◽

...

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Optimal Estimation ◽

Atmospheric Temperature ◽

Horizontal Resolution ◽

Forward Model ◽

Retrieval Algorithm ◽

Cloud Particle ◽

Cloud Data ◽

Temperature Water

Abstract. Single-footprint Atmospheric Infrared Sounder spectra are used in an optimal estimation-based algorithm (AIRS-OE) for simultaneous retrieval of atmospheric temperature, water vapor, surface temperature, cloud-top temperature, effective cloud optical depth and effective cloud particle radius. In a departure from currently operational AIRS retrievals (AIRS V6), cloud scattering and absorption are in the radiative transfer forward model and AIRS single-footprint thermal infrared data are used directly rather than cloud-cleared spectra (which are calculated using nine adjacent AIRS infrared footprints). Coincident MODIS cloud data are used for cloud a priori data. Using single-footprint spectra improves the horizontal resolution of the AIRS retrieval from ∼  45 to ∼  13.5 km at nadir, but as microwave data are not used, the retrieval is not made at altitudes below thick clouds. An outline of the AIRS-OE retrieval procedure and information content analysis is presented. Initial comparisons of AIRS-OE to AIRS V6 results show increased horizontal detail in the water vapor and relative humidity fields in the free troposphere above the clouds. Initial comparisons of temperature, water vapor and relative humidity profiles with coincident radiosondes show good agreement. Future improvements to the retrieval algorithm, and to the forward model in particular, are discussed.

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LOW-TEMPERATURE WATER-VAPOR CONVERSION OF ETHANOL ON THE Ni/ZnO CATALYST IN A MICROCHANNEL REACTOR

Alternative Energy and Ecology (ISJAEE) ◽

10.15518/isjaee.2016.15-18.112-121 ◽

2016 ◽

pp. 112-121 ◽

Cited By ~ 3

Author(s):

V. V. Grinko ◽

V. S. Bezhok ◽

N. V. Lapin ◽

A. F. Vyatkin

Keyword(s):

Water Vapor ◽

Low Temperature ◽

Microchannel Reactor ◽

Temperature Water

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Popcorn-like aluminum-based powders for instant low-temperature water vapor hydrogen generation

Materials Today Energy ◽

10.1016/j.mtener.2020.100602 ◽

2020 ◽

pp. 100602

Author(s):

Xinren Chen ◽

Cuiping Wang ◽

Yuheng Liu ◽

Yansong Shen ◽

Qijun Zheng ◽

...

Keyword(s):

Water Vapor ◽

Low Temperature ◽

Hydrogen Generation ◽

Temperature Water

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HGPT2: An ERA5-Based Global Model to Estimate Relative Humidity

Remote Sensing ◽

10.3390/rs13112179 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2179

Author(s):

Pedro Mateus ◽

Virgílio B. Mendes ◽

Sandra M. Plecha

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Real Time ◽

Prediction Models ◽

Weather Prediction ◽

Precipitable Water ◽

Precipitable Water Vapor ◽

Global Navigation Satellite Systems ◽

International Gnss Service ◽

Weighted Mean Temperature

The neutral atmospheric delay is one of the major error sources in Space Geodesy techniques such as Global Navigation Satellite Systems (GNSS), and its modeling for high accuracy applications can be challenging. Improving the modeling of the atmospheric delays (hydrostatic and non-hydrostatic) also leads to a more accurate and precise precipitable water vapor estimation (PWV), mostly in real-time applications, where models play an important role, since numerical weather prediction models cannot be used for real-time processing or forecasting. This study developed an improved version of the Hourly Global Pressure and Temperature (HGPT) model, the HGPT2. It is based on 20 years of ERA5 reanalysis data at full spatial (0.25° × 0.25°) and temporal resolution (1-h). Apart from surface air temperature, surface pressure, zenith hydrostatic delay, and weighted mean temperature, the updated model also provides information regarding the relative humidity, zenith non-hydrostatic delay, and precipitable water vapor. The HGPT2 is based on the time-segmentation concept and uses the annual, semi-annual, and quarterly periodicities to calculate the relative humidity anywhere on the Earth’s surface. Data from 282 moisture sensors located close to GNSS stations during 1 year (2020) were used to assess the model coefficients. The HGPT2 meteorological parameters were used to process 35 GNSS sites belonging to the International GNSS Service (IGS) using the GAMIT/GLOBK software package. Results show a decreased root-mean-square error (RMSE) and bias values relative to the most used zenith delay models, with a significant impact on the height component. The HGPT2 was developed to be applied in the most diverse areas that can significantly benefit from an ERA5 full-resolution model.

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