scholarly journals Влияние турбулентности и восходящих потоков воздуха на дочерние продукты распада радона

2021 ◽  
pp. 200-209
Author(s):  
A.S. Zelinskiy ◽  
G.A. Yakovlev
Keyword(s):  
Turbulent Mixing ◽  
Activity Ratio ◽  
Radon Progeny ◽  
Air Velocity ◽  
Radioactive Equilibrium ◽  
Air Movement ◽  
The Relationship ◽  
Atmospheric Radon ◽  
Different Altitudes ◽  
Atmospheric Inversion

In this paper, a simulation of the distribution of radon progeny over the height of the atmosphere, depending on the amount of turbulent mixing and the vertical air velocity, is presented. The obtained results are compared with the change in the activity ratio of Bi-214/Pb-214 isotopes recorded in rainwater during 3-year observations in Prague. It is found that the reasons for the most common values of Bi-214/Pb-214 can be the height of the lower edge of the cloud of 0.2-1.4 km and the vertical air velocity of 0.1 – 0.2 m / s. The ratio changes slightly from changes in the turbulent mixing, the value of the vertical air movement makes the main contribution. It is found that with the increase in the intensity of rain, a shift in the radioactive equilibrium should occur due to an increase in the velocity of vertical air. Atmospheric inversion is able to balance the volumetric activities of the descendants of atmospheric radon, atmospheric inversion can be identified by the equality between the activities of the radon progeny in the atmosphere at different altitudes or in rainwater. It is shown that the search for the relationship between precipitation intensity and gamma radiation is expose to error, without taking into account the influence of the АBi−214/АPb−214 ratio, due to the unequal activities of the atmospheric isotopes Bi-214 and Pb-214. This error of 7-14% when using gamma radiometry, and of 5-9% when using dosimeters is estimated. олучены результаты моделирования распределения дочерних продуктов радона в атмосферном столбе по высоте, объясняющие изменение концентраций радионуклидов в дождевой воде в зависимости от высоты нижней кромки облаков. Значения соотношений активностей АBi−214/АPb−214 радионуклидов дождевой воды от 0.6 до 0.8, могут возникать при высоте нижней кромки облаков от 0.2 до 1.4 км и адвекции от 0.1 до 0.2 м/с соответственно. Произведена оценка шибки от 7 до 14%, возникающая при использовании гамма радиометров, и от 5 до 9% — дозиметров, во время осадков с целью поиска корреляции роста гамма-фона и интенсивности жидких ливневых осадков.

The Investigation of People Using Air Movement Actively in Summer in Hot-Humid Area of China

2011 ◽  
Vol 121-126 ◽  
pp. 602-606 ◽  
Author(s):  
Qian Ni Liu ◽  
Yu Feng Zhang ◽  
Qing Lin Meng
Keyword(s):  
College Students ◽  
Air Velocity ◽  
Raw Data ◽  
Main Motivation ◽  
Air Movement ◽  
Humid Area ◽  
Hot And Humid Climates ◽  
Naturally Ventilated Buildings ◽  
The Relationship

This paper is focused on the relationship between the motivations for people to actively use air movement and indoor climates, with an aim to determine the preferred levels of air movement for the occupants of naturally ventilated buildings in hot and humid climates in China. Based on 429 questionnaires collected in a background survey, 29 college students were chosen to join in the transverse survey. Totally 247 sets of raw data in 5 weeks were obtained. Primary results show that the main motivation of opening window changed from “fresh air” to “cool room and body” as the summer coming. The proportion of wanting more air movement increased as ET* rose, and the ambient and preferred air velocity increased linearly with ET* too.

scholarly journals Flow Structures of the Air-Water Layer in the Free Surface Region of High-Speed Open Channel Flows

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Feng Jiang ◽  
Weilin Xu ◽  
Jun Deng ◽  
Wangru Wei
Keyword(s):  
Free Surface ◽  
Layer Thickness ◽  
High Speed ◽  
Open Channel ◽  
Water Layer ◽  
Channel Flows ◽  
Flow Structures ◽  
Air Velocity ◽  
Open Channel Flows ◽  
The Relationship

In hydraulic engineering, intense free surface breakups have been observed to develop in high-speed open channel flows, resulting in a mixed air-water layer near the free surface that grows with the development of self-aeration. This region is characterized by a substantial number of droplets coexisting with an induced air layer above. Little information about this droplet layer is currently available and no practicable approach has been proposed for predicting the parameters of the induced air layer based on the related flow structures in the droplet layer. In this research, laboratory experiments were accordingly conducted to observe the detailed droplet layer development in terms of layer thickness, droplet size, and frequency distributions under comparative flow conditions. Based on the simplified droplet layer roughness determined using the experimentally measured mean droplet size, the classical power-law of boundary layer theory was applied to provide an analytical solution for the air velocity profile inside the air layer. The relationship of air layer growth to droplet layer thickness, which is a key factor when determining the air velocity distribution, was also established, and the analytical results were proven to be in reasonable agreement with air velocity profiles presented in the literature. By determining the relationship between droplet layer properties and air velocity profiles, the study establishes a basis for the improved modeling of high-speed open channel flows.

THE EFFECT OF WIND AND MOISTURE ON HEAT LOSS THROUGH THE FUR OF NEWBORN CARIBOU

1960 ◽  
Vol 38 (4) ◽  
pp. 679-688 ◽  
Author(s):  
C. P. Lentz ◽  
J. S. Hart
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Loss ◽  
Physical Characteristics ◽  
Air Velocity ◽  
Direction Parallel ◽  
Air Movement

The effects of air velocity and direction and of wetness on rate of heat transfer were studied in tests with samples of fur from five caribou calves. The rate of heat transfer through this fur increased by a factor of two to three with increase in air velocity from a negligible level (natural convection) to 23 m/second (direction parallel to sample). The effect of air velocity varied markedly (up to ±50% at 23 m/second) with inclination of the sample to the direction of air movement. Spraying water on the fur increased its rate of heat transfer markedly; addition of water equivalent to 10–12% of the volume of the fur doubled the rate of heat transfer. Other factors, such as erectness of the fur, direction of the hairs or "grain" of the fur with respect to the direction of air movement, and wetness of the skin also affected heat transfer. Differences between samples were large and did not appear to depend directly on the physical characteristics measured.

scholarly journals Influence of Wind on Air Movement in a Free-Stall Barn During the Summer Period / Wpływ wiatru na ruch powietrza w oborze wolnostanowiskowej w okresie letnim

2013 ◽  
Vol 13 (1) ◽  
pp. 109-119 ◽  
Author(s):  
Piotr Herbut ◽  
Sabina Angrecka ◽  
Grzegorz Nawalany
Keyword(s):  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation System ◽  
Air Velocity ◽  
Summer Period ◽  
Air Masses ◽  
Air Movement ◽  
Microclimatic Conditions ◽  
Hot Weather ◽  
Different Levels

Abstract Use of natural ventilation in the barn should lead to optimal microclimatic conditions over the entire space. In the summer, especially during hot weather, higher air velocity cools cows, which helps to avoid heat stress. The paper presents the results of studies on the evolution of air movement in a modernized free-stall barn of the Fermbet type with the natural ventilation system during the summer period. Based on measurements of velocity and direction of air flow (inside and outside the barn) and observations of smoke indicator, the movement of air masses in different parts of the barn was identified. Significant variations of air flow at different levels of the barn were found. These differences deviate from the accepted patterns of natural ventilation, which can be found in the literature. The range of a draught and stagnant air along with the conditions in which they are built was determined. On this basis, recommendations regarding the location of barns on the plots and the improvement of ventilation in summer were made.

scholarly journals The criterion of the presumption of biophysiological temperature and the cooling guide for the determination of human comfort in the City of Rutba

2018 ◽  
Vol 227 (2) ◽  
pp. 307-316
Author(s):  
Lect. Intisar Sukkar Khioun
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Climatic Data ◽  
Human Comfort ◽  
Air Movement ◽  
The Impact ◽  
The Relationship ◽  
The City ◽  
Climate Studies

     The relationship between man and climate is of great importance in climate studies, as climate is the most natural climatic element in the sense of comfort or distress of man, and humans can live comfortably if the degree of heat between (17-31 m) and the human feeling of heat and cold and then rest or discomfort not only caused by the air temperature but depends on many elements including solar radiation, air movement, relative humidity, the level of human activity and the type of clothing worn, and the presumption has used Biophysiological temperature and Cooling guide in this study to demonstrate the impact of climate on human comfort in the city of Rutba and relying on the climatic data for thirty years.

scholarly journals CHARACTERATION OF AIR MOVEMENT PATTERNS AND VELOCITY EFFECIS ON PLANT DEVELOPMENT IN A GROWTH CHAMBER

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1151a-1151
Author(s):  
R.L. Korthals” ◽  
S.L. Knight ◽  
L.L. Christianson
Keyword(s):  
Plant Development ◽  
Horizontal Velocity ◽  
Growth Chamber ◽  
Hot Wire ◽  
Plant Growth And Development ◽  
Air Velocity ◽  
Experimental Conditions ◽  
Node Number ◽  
Air Movement ◽  
Practical Implications

Chrysanthemum, wheat, and soybean were grown in a growth chamber to study the effects of airflow direction, velocity, and turbulence on vegetative growth. These three plant species were chosen to examine how plants with different leaf architectures and morphology are influenced by varying air velocity and pattern. A hot wire anemometer accurate to ±0.025 m s-1 and capable of responding to 50 khz turbulent velocity fluctuations was used to characterize the environment in a growth chamber under three different experimental conditions: <0.50 m s-1 horizontal velocity, >1.00 m s-1 horizontal velocity, and <0.50 m s-1 vertical velocity. Plants were grown under the three different treatments for five weeks with plant height, width, stem diameter, and node number, and fresh and dry weights of leaves, stem, and roots determined at three internals throughout each experiment. Tire variation in plant development resulting from the different treatments has practical implications for using ventilation to aid in controlling plant growth and development.

scholarly journals Users’ Sensations in the Context of Energy Efficiency Maintenance in Public Utility Buildings

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8159
Author(s):  
Edyta Dudkiewicz ◽  
Marta Laska ◽  
Natalia Fidorów-Kaprawy
Keyword(s):  
Energy Efficiency ◽  
Relative Humidity ◽  
Thermal Sensation ◽  
Co2 Concentration ◽  
Public Utility ◽  
Temperature Changes ◽  
The Public ◽  
Air Movement ◽  
Indoor Conditions ◽  
The Relationship

Research towards understanding the relationship between maintaining thermal comfort and energy efficiency in the public utility buildings was undertaken among 323 1st year students during class hours. Questionnaires surveys and measurements of indoor conditions were performed. The article identified students’ sensations and perceptions concerning indoor conditions. Temperature, relative humidity, air velocity and CO2 concentration measured to assess room conditions showed that the auditorium had almost comfortable conditions according to the literature guidelines. The indices used to assess students’ perceptions were: Thermal Sensation Vote (TSV), Thermal Preference Vote (TPV), Air Freshness Sensation Vote (AfSV), Air Movement Preference Vote (AmPV), and Relative Humidity Preference Vote (RHPV). The interpretation of these indicators showed that while the students’ requests for temperature changes and increased air movement are adequate for the air conditions in the room, the evaluation of stuffiness and requests for changes in humidity levels are surprising. Striving uncritically to meet the desired room parameters, according to the users votes, can lead to deterioration of the air and not only the increase in energy consumption but even waste it. Better understanding of users’ preferences and behaviour and further application of this knowledge indirectly aim at increasing energy efficiency in buildings.

scholarly journals Thermal comfort, thermal sensation and skin temperature measurements using demand-controlled ventilation for individual cooling

2020 ◽  
Vol 172 ◽  
pp. 06001
Author(s):  
Håkon Solberg ◽  
Kari Thunshelle ◽  
Peter Schild
Keyword(s):  
Thermal Comfort ◽  
Skin Temperature ◽  
Energy Demand ◽  
Thermal Sensation ◽  
Air Velocity ◽  
Climate Chamber ◽  
Biometric Data ◽  
Ongoing Research ◽  
Demand Controlled Ventilation ◽  
The Relationship

An increasing part of modern building's energy demand is due to cooling. An ongoing research project investigates the possibility to reduce the energy consumption from cooling by utilizing an individually controlled active ventilation diffuser mounted in the ceiling. This study looks at thermal sensation and thermal comfort for 21 test persons exposed to an innovative user controlled active ventilation valve, in a steady and thermally uniform climate chamber. Furthermore, the relationship between biometric data from the test persons skin temperature and sweat, and the test persons thermal sensation scores has been investigated. Each test person was exposed to three different room temperatures in the climate chamber, 24°C, 26°C and 28°C respectively, to simulate typical hot summer conditions in an office in Norway. At a room temperature of 26°C it was possible to achieve acceptable thermal comfort for most test persons with this solution, but higher air velocity than 0.75 m/s around the test persons bodies at room temperatures of 28°C is required to ensure satisfactory thermal comfort.

scholarly journals The effect of air velocity on moisture buffering

2019 ◽  
Vol 282 ◽  
pp. 02007 ◽  
Author(s):  
Valeria Cascione ◽  
Eugenio Cavone ◽  
Daniel Maskell ◽  
Andy Shea ◽  
Pete Walker
Keyword(s):  
Air Quality ◽  
Relative Humidity ◽  
Buffering Capacity ◽  
Climatic Chamber ◽  
Air Velocity ◽  
Speed Distribution ◽  
Velocity Correction ◽  
Air Speed ◽  
The Relationship ◽  
Moisture Buffering

Hygoscopic finishing materials improve the indoor hygrothermal comfort and air quality, as they reduce the extremes of variation in relative humidity. This property, known as moisture buffering, is related to the capacity of hygroscopic materials to adsorb and desorb moisture from the air. Air velocity plays an important role on the sorption performances of materials: increasing the air speed leads to increased moisture buffering capacity. In order to obtain comparable results, several moisture buffering protocols require the air speed to be constant and around 0.1 m/s during tests. However, those tests are usually performed in climatic chambers, where air speed cannot be controlled and the flow may not be homogenous. The aim of this study is to demonstrate, that positioning test specimens in different locations within the same chamber gives different moisture buffering value results, due to the non-homogenous air speed distribution. For this reason, air velocity has been monitored, measuring the differential pressure and air speed in different locations in a climatic chamber. Moisture buffering tests have been performed in six locations of the chamber and a correlation between the two analyses has been evaluated. The significance of this paper is to understand the relationship between air speed and moisture buffering performances, in order to determine an air velocity correction factor, which enables the moisture buffering value to be evaluated when existing protocols cannot be adhered.

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