Experimental Investigation of Long-Term Humidity Variations in a Thermally Stabilised Chamber

2020 ◽  
pp. 71-77
Author(s):  
Il.S. Golyak ◽  
A.N. Morozov ◽  
M.A. Strokov
Keyword(s):  
Experimental Investigation ◽  
Relative Humidity ◽  
Absolute Humidity ◽  
The Sun ◽  
Atmospheric Air ◽  
Measurement Results ◽  
Periodic Signals ◽  
The Difference ◽  
Long Term Measurement

The paper presents long-term measurement results concerning relative humidity in a thermally stabilised chamber. We show that the relative humidity values inside the chamber correlate with the absolute humidity of the atmospheric air. We detected the presence of 16- and 30-day periodic signals in the spectra of the difference between the relative humidity inside the thermally stabilised chamber and the orthonormal absolute humidity of the atmospheric air. We also discovered the presence of periodic signals in the periodogram of variations in relative humidity inside the thermally stabilised chamber; the periods of those signals are 1436 and 1440 minutes, which corresponds to the period of the Earth's rotation around its axis, taking into account its rotation around the Sun

scholarly journals Sorptive testing of mortars with varying water-cement ratios

2018 ◽  
Vol 49 ◽  
pp. 00107
Author(s):  
Agata Stolarska ◽  
Szymon Ciborowski
Keyword(s):  
Relative Humidity ◽  
Real Life ◽  
Side Surface ◽  
Constant Weight ◽  
Three Samples ◽  
Water To Cement Ratio ◽  
Measurement Results ◽  
Similar Density ◽  
Long Term Measurement

The article presents the results of studies on sorption performed on three samples of mortars with similar density of about 2,000 kg/m3. The tested mortars differed in their water-to-cement ratio. Three levels of w/c ratio were adopted that were respectively: 0.5; 0.55 and 0.6. The prepared mortars were cut into samples with a thickness of 1 cm, dried to constant weight at a temperature of 105°C and insulated on the side surface with silicone. The experiment was carried out at a temperature of 25°C and at six different levels of relative humidity φ ≈ 12, 33, 54, 76, 85, 98%. Relative humidity was provided by saturated solutions of the appropriate salts: LiCl (φ ≈ 12%), MgCl2 (φ ≈ 33%), Mg(NO3)2 (φ ≈ 53%), NaCl (φ ≈ 76%), KCl (φ ≈ 85%), K2SO4 (φ ≈ 98%). The adopted level of temperature and range of relative humidity meet the hygrothermal conditions which tend to affect the cement mortar in real life. The long-term measurement results were used to assess the behaviour of the tested mortars under various conditions of moisture and to determine the equilibrium sorptive humidity.

scholarly journals Efektifitas Pembayangan yang dihasilkan Pohon dan Bangunan di Koridor Jalan Perkotaan Untuk Mencapai Kenyamanan Termal

2018 ◽  
Vol 4 (1) ◽  
pp. 65-70
Author(s):  
Jockie Zudhy Fibrianto ◽  
Mochamad Hilmy
Keyword(s):  
Thermal Comfort ◽  
Temperature Difference ◽  
Weather Conditions ◽  
The Sun ◽  
The Road ◽  
Analysis Phase ◽  
Measurement Results ◽  
The Difference ◽  
Road Corridors ◽  
East West

The road corridor in Pontianak City has different shading output depending on the sun orientation. The difference has caused a temperature difference that affects the pedestrian thermal comfort along the corridor. Identification and measurement of shading temperatures that occur due to buildings and trees were carried out for three days in each afternoon with relatively similar weather conditions. The road corridor that becomes the research location was at A. Yani St.-Gajah Mada St.-Tanjung Pura St., which has a North-South orientation and Teuku Umar St.-Diponegoro St.-Sisingamangaraja St., who has an East-West direction. The analysis phase is done by comparing the effectiveness of imagery produced by buildings and trees. After that, the identification and measurement results are compared with Indonesian thermal comfort standards SNI T-14-1993-03 to obtain suitable thermal comfort in the road corridors in Pontianak City.

scholarly journals I. Numerical elements of Indian meteorology.—Series II. Insolation, and its connexion with atmospheric moisture

1865 ◽  
Vol 14 ◽  
pp. 111-112
Keyword(s):  
Relative Humidity ◽  
The Other ◽  
The Sun ◽  
Atmospheric Moisture ◽  
Different Seasons ◽  
The Difference ◽  
Maximum Temperatures ◽  
Different Parts

The author regards as an approximate measure of insolation the difference of the maximum temperatures observed by two similar thermometers one in the sun, and the other in the shade, disturbing influences being as much as possible avoided in both cases, and the observations being confined to those days on which the sun shone sufficiently clearly to cast a distinct shadow during some part of the interval between noon and 4 p .m . Comparing the differences of insolation in different parts of India and in different seasons, he is led to regard insolation as dependent greatly on relative humidity. Thus, generally speaking, it is greater on the seaboard than in the interior of India.

scholarly journals Hygrothermal assessment of roofs with above-rafter thermal insulation in the detail of the eave overhang

2019 ◽  
Vol 10 (1) ◽  
pp. 29-34
Author(s):  
Pavel Soudek ◽  
Lubor Kalousek ◽  
Antonín Žák
Keyword(s):  
Relative Humidity ◽  
Thermal Insulation ◽  
Measuring Method ◽  
Roof System ◽  
Roof Structure ◽  
Long Term Measurement ◽  
Real Building

This paper is focused on hygrothermal assessment of the eave overhang detail in above-rafter placed thermal insulation roof system. Results of the long-term measurement of this detail performed on a real building as well as the testing of the measuring method are presented in this paper. Within this measurement the moisture of wooden elements performing an eave overhang of the roof was monitored primarily in order to verify their long-term functionality. In addition the temperature and relative humidity in the roof structure were measured as well. As part of this measurement, various design variants of above mentioned detail in combination with different compositions of the roof structure were compared. The long-term functionality of the assessed details is evaluated in the conclusion of this paper, taking into account especially hygrothermal status of wooden element, which is associated with threats of infestation of these elements by wood decaying fungi or insects.

Extraterrestrial Solar Radiation

2017 ◽  
pp. 91-190
Keyword(s):  
Solar Radiation ◽  
Horizontal Plane ◽  
Simple Formula ◽  
Energy Gain ◽  
The Sun ◽  
Solar Constant ◽  
A Value ◽  
Declination Angle ◽  
The Difference

Extraterrestrial solar radiation is the main source of terrestrial solar radiation components. Data on the spectrum of this radiation is available and a value of 1367 Wm-2 for the solar constant is accepted in solar literature. The knowledge of extraterrestrial solar radiation is essential for solar applications, within them is the Sun tracking. This radiation on horizontal surface is widely treated and a simple formula, for calculating it, is widely used. On Equator facing solar receivers, the appropriate equations for obtaining this radiation are also available, but the application of these equations by different authors was found to be not evident mainly on calculating the sunset hour angle on such surfaces. This question becomes problematic for some authors when treating surfaces of different orientations. The term of characteristic day is widely used in solar literature. The ambiguity of this term with regard to extraterrestrial solar radiation, declination angle and extraterrestrial solar radiation on a horizontal plane is described. In order to completely solve the above-mentioned problems, extraterrestrial solar radiation is calculated on surfaces of different orientations and the required relations are given for each case. The introduction of the energy gain on the basis of extraterrestrial solar radiation could be formulated mathematically very precisely. Therefore, this question is treated in details in this chapter. The difference between short term and long term Sun tracking is described also and the maximum possible energy gain of these two types of tracking is characterized.

scholarly journals QIBLA DIRECTION WITH THE CONSTELLATION (STUDY OF DETERMINATION OF QIBLA DIRECTION WITH GUBUG PENCENG)

2021 ◽  
Vol 2 (2) ◽  
pp. 162-193
Author(s):  
M Ihtirozun Ni'am ◽  
Muhammad Fiki Burhanuddin ◽  
Nizma Nur Rahmi
Keyword(s):  
Field Research ◽  
Central Point ◽  
The Sun ◽  
Naked Eye ◽  
Measurement Results ◽  
Numerical Research ◽  
The Difference

In the ethnography of Javanese society, Gubug penceng is used as a southern constellation. With a declination value of -63º 05’ 57”, the appearance of this gubug penceng is a bit unique, because it can only be observed by observers who are south of the tropic. However, with a magnitude value of 0.77 and a shape that is easy to remember, it makes the gubug becomes a star that is easily visible to the naked eye. The author here will examine the use of the gubug penceng for determining the direction of the Qibla. Previous writers will take into account the azimuth of the Qibla and the azimuth of the acrux star which is the brightest star in the constellation of the thinner, then determine the direction of the Qibla by referring to the difference between the azimuth acrux and the qibla. This research is a field research which is included in qualitative numerical research. The author will compare the results of the Qibla direction from this gubug penceng with the Qibla direction determined with the help of the azimuth of the Sun. The results of this study found that the gubug penceng can be used as a reference to determine the direction of the Qibla. The qibla direction of the measurement results is quite accurate, because the object of aiming is in the form of a central point of the star. The difference between the direction of the Qibla between using the reference hut is not more than 24 minutes, so the results are quite accurate.

scholarly journals Long-term Effects of Relative Humidity on Properties of Microwave Hardened Moulding Sand with Sodium Silicate

2017 ◽  
Vol 17 (3) ◽  
pp. 127-132 ◽  
Author(s):  
M. Stachowicz ◽  
K. Granat
Keyword(s):  
Relative Humidity ◽  
Sodium Silicate ◽  
Water Glass ◽  
Atmospheric Conditions ◽  
Technological Properties ◽  
Long Term Effects ◽  
Technological Parameters ◽  
Atmospheric Air ◽  
Moulding Sand

AbstractMoulding sands containing sodium silicate (water-glass) belong to the group of porous mixture with low resistance to increased humidity. Thanks to hydrophilic properties of hardened or even overheated binder, possible is application of effective methods of hydrous reclamation consisting in its secondary hydration. For the same reason (hydrophilia of the binder), moulds and foundry cores made of high-silica moulding sands with sodium silicate are susceptible to the action of components of atmospheric air, including the contained steam. This paper presents results of a research on the effect of (relative) humidity on mechanical and technological properties of microwave-hardened moulding mixtures. Specimens of the moulding sand containing 1.5 wt% of sodium water-glass with module 2.5 were subjected, in a laboratory climatic chamber, to long-term action of steam contained in the chamber atmosphere. Concentration of water in atmospheric air was stabilized for 28 days (672 h) according to the relative humidity parameter that was ca. 40%, 60% and 80% at constant temperature 20 °C. In three cycles of the examinations, the specimens were taken out from the chamber every 7 days (168 h) and their mechanical and technological parameters were determined. It was found on the grounds of laboratory measurements that moulds and cores hardened with microwaves are susceptible to action of atmospheric air and presence of water (as steam) intensifies action of the air components on glassy film of sodium silicate. Microwave-hardened moulding sands containing sodium silicate may be stored on a long-term basis in strictly determined atmospheric conditions only, at reduced humidity. In spite of a negative effect of steam contained in the air, the examined moulding mixtures maintain a part of their mechanical and technological properties, so the moulds and foundry cores stored in specified, controlled conditions could be still used in manufacture.

scholarly journals Role of meteorological temperature and relative humidity in the January-February 2020 propagation of 2019-nCoV in Wuhan, China

2020 ◽  
Author(s):  
Jose Alvarez-Ramirez ◽  
Monica Meraz
Keyword(s):  
Relative Humidity ◽  
Mainland China ◽  
Absolute Humidity ◽  
Human Contact ◽  
Transmission Mechanisms ◽  
High Incidence ◽  
Potential Risks ◽  
Averaging Filter

AbstractIdentified in December 2019, the 2019-nCoV emerged in Wuhan, China, and its spread increased rapidly, with cases arising across Mainland China and several other countries. By January 2020, the potential risks imposed by 2019-nCoV in human health and economical activity were promptly highlighted. Considerable efforts have been devoted for understanding the transmission mechanisms aimed to pursue public policies oriented to mitigate the number of infected and deaths. An important question requiring some attention is the role of meteorological variables (e.g., temperature and humidity) in the 2019-nCoV transmission. Correlations between meteorological temperature and relative humidity with the number of daily confirmed cases were explored in this work for the epicenter city of Wuhan, China for the period from 29 January to March 6, 2020. Long-term trend of temperature and relative humidity was obtained with a 14-days adjacent-averaging filter, and lagged correlations of the number of daily confirmed cases were explored. The analysis showed negative correlations between temperatures with the number of daily confirmed cases. Maximum correlations were found for 6-day lagged temperatures, which is likely reflecting the incubation period of the virus. It was postulated that the indoor crowding effect is responsible of the high incidence of 2019-nCoV cases, where low absolute humidity and close human contact facilitate the transport of aerosol droplets.

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