scholarly journals Assessing the effect of a coating system on the rate of plywood moistening and changes in dimensions in relation to the change in relative air humidity

2012 ◽  
Vol 50 (No. 2) ◽  
pp. 86-100
Author(s):  
P. Král ◽  
J. Hrázský
Keyword(s):  
Surface Coating ◽  
Bending Strength ◽  
Coating System ◽  
Institutional Research ◽  
Air Humidity ◽  
Surface Layers ◽  
Dimensional Changes ◽  
Relative Air Humidity ◽  
Sheet Structure ◽  
Axis Of Symmetry

The paper summarizes results of an institutional research aimed at the evaluation of the effect of a coating system on the rate of plywood moistening and changes in dimensions in relation to changes in relative air humidity. Coefficients of dimensional changes were determined in relation to relative air humidity and effects were studied of the coating system on the rate of plywood moistening. All measurements were carried out in water-resistant combined plywood with surface coating and thickness of 8, 10, 12, 15 and 18 mm and in all-beech plywood 10, 12, 15 and 18 mm in thickness. Based on the results obtained it is possible to state that bending strength and modulus of elasticity are decisively affected by the construction of a sheet. Therefore, it is suitable to select the sheet structure according to requirements of a customer. It is known that surface layers transfer the greatest stress and that the stress of layers decreases towards the axis of symmetry. The fact can be used in designing the sheet structure, e.g. using veneers manufactured from cheaper species for central layers. Thus, the price and even density of plywood can be substantially reduced maintaining the required strength. By means of coats it is possible to reduce substantially penetration of moisture across the plywood edge. Comparisons between polyurethane coat U 2070 and acrylate coat AQUACOL V 2080 are demonstrated in <br />a figure. Changes in the length and width of combined plywood and all-beech plywood amount to on average 0.020&ndash;0.025% per <br />1% change in moisture. Under upper values of the moisture range the changes are generally substantially lower. In practice, a suitable clearance for changes in the length and width of plywood amounts to 2 mm/m. Changes in thickness reach on average 0.4&ndash;0.5% per 1% changes in the moisture content.

Visco-elastic changes of vocal fold mucosa related to high and low relative air humidity

2000 ◽  
Vol 25 (4) ◽  
pp. 329-330
Author(s):  
R.J.B. Hemler ◽  
G.H. Wieneke ◽  
P.H. Dejonckere
Keyword(s):  
Vocal Fold ◽  
Air Humidity ◽  
Relative Air Humidity

Clinical, epidemiological and climatic factors related to the occurrence of cutaneous leishmaniasis in an endemic area in northeastern Brazil

2020 ◽  
Author(s):  
R. S. Oliveira ◽  
K. B. A. Pimentel ◽  
M. L. Moura ◽  
C. F. Aragão ◽  
A. S. Guimarães-e-Silva ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Climatic Factors ◽  
Wide Distribution ◽  
Northeastern Brazil ◽  
Public Health Issue ◽  
Air Humidity ◽  
Disease Occurrence ◽  
Relative Air Humidity ◽  
Age Range ◽  
And Control

Abstract Cutaneous leishmaniasis (CL) is a neglected tropical disease with a wide distribution in the Americas. Brazil is an endemic country and present cases in all states. This study aimed to describe the occurrence, the underlying clinical and epidemiological factors, and the correlation of climatic variables with the frequency of reported CL cases in the municipality of Caxias, state of Maranhão, Brazil. This is a retrospective and descriptive epidemiological study based on data extracted from the Brazilian Information System of Diseases Notification, from 2007 to 2017. Maximum and minimum temperature, precipitation, and relative air humidity data were provided by the Brazilian National Institute of Meteorology. A total of 201 reported autochthonous CL cases were analyzed. The predominance of cases was observed in males (70.1%). The age range between 31 and 60 years old was the most affected, with 96 cases (47.9%). Of the total number of registered cases, 38.8% of the affected individuals were engaged in agriculture-related activities. The georeferenced distribution revealed the heterogeneity of disease occurrence, with cases concentrated in the Western and Southern regions of the municipality. An association was detected between relative air humidity (monthly mean) and the number of CL cases per month (p = 0.04). CL continues to be a concerning public health issue in Caxias. In this context, there is a pressing need to strengthen measures of prevention and control of the disease through the network of health services of the municipality, considering local and regional particularities.

scholarly journals Responses of Rice Growth to Day and Night Temperature and Relative Air Humidity—Leaf Elongation and Assimilation

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 134
Author(s):  
Sabine Stuerz ◽  
Folkard Asch
Keyword(s):  
Leaf Area ◽  
Leaf Growth ◽  
Crop Growth ◽  
Air Humidity ◽  
Leaf Elongation ◽  
Night Temperature ◽  
Relative Air Humidity ◽  
Leaf Area Expansion ◽  
Plant Level ◽  
Area Expansion

Predictions of future crop growth and yield under a changing climate require a precise knowledge of plant responses to their environment. Since leaf growth increases the photosynthesizing area of the plant, it occupies a central position during the vegetative phase. Rice is cultivated in diverse ecological zones largely differing in temperature and relative air humidity (RH). To investigate the effects of temperature and RH during day and night on leaf growth, one variety (IR64) was grown in a growth chamber using 9 day/night regimes around the same mean temperature and RH, which were combinations of 3 temperature treatments (30/20 °C, 25/25 °C, 20/30 °C day/night temperature) and 3 RH treatments (40/90%, 65/65%, 90/40% day/night RH). Day/night leaf elongation rates (LER) were measured and compared to leaf gas exchange measurements and leaf area expansion on the plant level. While daytime LER was mainly temperature-dependent, nighttime LER was equally affected by temperature and RH and closely correlated with leaf area expansion at the plant level. We hypothesize that the same parameters increasing LER during the night also enhance leaf area expansion via shifts in partitioning to larger and thinner leaves. Further, base temperatures estimated from LERs varied with RH, emphasizing the need to take RH into consideration when modeling crop growth in response to temperature.

scholarly journals Relationship between preterm birth and air pollution in Santos, Sao Paulo, Brazil

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M E L Brandao ◽  
B A L F Braga ◽  
M L C Martins ◽  
P L A A Pereira
Keyword(s):  
Air Pollution ◽  
Preterm Birth ◽  
Air Pollutants ◽  
First Trimester ◽  
Sao Paulo ◽  
São Paulo ◽  
Air Humidity ◽  
Relative Air Humidity ◽  
The Impact ◽  
Fourth Quartile

Abstract Santos is a seaboard Brazilian city recognized by its port activity where the road and rail infrastructure along with the large transportation operation, displays an important factor to contribute with all kinds of toxic and air pollutants. Recent studies have suggested associations between air pollution and various birth outcomes. Pollutant gases such as NOx, O3 and particulate matter PM2,5, PM10 have been cited as factors involved in such outcomes. The present study aims to assess the relationship between atmospheric pollutants and perinatal outcomes in the city of Santos from Jan. 2012 to Dec. 2015. Cross-sectional study that analyzed 10.319 singleton births in an area set with 2 km radius of the monitoring stations. Birth weight and information on mother and pregnancy were obtained at the Brazilian “Born Alive National Information System”. Daily records of air pollutants (PM10, PM2.5, NO2 and O3), temperature and relative air humidity, for the study period, were obtained from São Paulo State Environmental Agency (CETESB). Associations between preterm birth and air pollutants mean levels at each gestational trimester were investigated using multiple logistic regression model controlled by the variables: infant sex, type of delivery, maternal education. prenatal care, and number of previous live births, temperature and relative air humidity. NO2 e PM2,5 was not associated with preterm birth. O3 was significantly associated in the first trimester in the fourth quartile (OR = 1,47 CI 95% 1,05; 2,07). PM10 was significantly associated in the first trimester for the fourth quartile (OR = 1,28 CI 95% 1,00; 1,64), second trimester for the second quartile (OR = 1,37 CI 95% 1,07; 1,77). Conclusions the results shows evidence that maternal exposure to air pollution especially during the first trimester of pregnancy may contribute to preterm birth. Further actions are needed towards controlling air pollution are strongly recommended for promoting early-life health. Key messages This is the first research of this kind that was made in Santos. It brings important evidence of the impact in the life of the population, especially those whose is not even born yet. It can be used as a resource to guide public policies in health, especially the guidelines that dictate the concentration of air pollutants and air quality.

Chloride penetration into reinforced concrete slabs

1998 ◽  
Vol 25 (1) ◽  
pp. 87-95 ◽  
Author(s):  
A K Suryavanshi ◽  
R N Swamy ◽  
S McHugh
Keyword(s):  
Reinforced Concrete ◽  
Surface Coating ◽  
Lateral Diffusion ◽  
Chloride Penetration ◽  
Chloride Diffusion ◽  
Concrete Slabs ◽  
Coating System ◽  
Depth Of Penetration ◽  
Lateral Direction ◽  
Reinforced Concrete Slabs

The overall aim of this paper is to establish the process and amount of chlorides penetrating reinforced concrete elements when exposed to a salt-laden environment. For this purpose, a number of slabs were subjected to 70 cycles of wetting-drying regime with a 4% sodium chloride solution over a period of 2-3 years. To examine the direction of transportation of the chlorides, some of the slabs were partially coated with a surface coating system known to be highly resistant to chloride penetration. The amount and depth of penetration of chlorides in the coated and uncoated parts of the slab were then determined. The results show conclusively that, in large exposed areas of concrete, chlorides diffuse both in the direction of depth and in a direction lateral to the depth of the element. The amount of chlorides and the distance of their lateral diffusion depend on the water-to-cement (w/c) ratio of the concrete and the duration of exposure. Concrete mixes with a high w/c ratio (0.75) are highly conducive to this lateral diffusion of chlorides. Although concrete mixes of lower w/c ratios (0.45 and 0.60) are less conducive to lateral diffusion of chlorides, in practice, all concretes should be considered to be prone to chloride diffusion in both the direction of gravity and the lateral direction because of the effects of cracking. In unprotected concrete, reducing the w/c ratio from 0.60 to 0.45 is far more effective in decreasing chloride penetration than that achieved by reducing the w/c ratio from 0.75 to 0.60. The acrylic-based surface coating system is totally resistant to chloride penetration.Key words: chloride diffusion, concrete slabs, durability, water-to-cement ratio, surface coating, lateral diffusion.

Influence of Relative Air Humidity on Evaporation of Water–Ethanol Solution Droplets

2021 ◽  
Vol 83 (3) ◽  
pp. 277-283
Author(s):  
V. Yu. Borodulin ◽  
V. N. Letushko ◽  
M. I. Nizovtsev ◽  
A. N. Sterlyagov
Keyword(s):  
Ethanol Solution ◽  
Air Humidity ◽  
Relative Air Humidity

scholarly journals Hypertension, pregnancy and weather: is seasonality involved?

2014 ◽  
Vol 60 (2) ◽  
pp. 105-110 ◽  
Author(s):  
Brena Melo ◽  
Melania Amorim ◽  
Leila Katz ◽  
Isabela Coutinho ◽  
José Natal Figueiroa
Keyword(s):  
Relative Humidity ◽  
Correlation Coefficient ◽  
Pearson Correlation ◽  
Hypertensive Disorder ◽  
Air Humidity ◽  
Hypertensive Disorders Of Pregnancy ◽  
Monthly Temperature ◽  
Hypertensive Disorders ◽  
Relative Air Humidity ◽  
Hypertensive Disorder Of Pregnancy

Objective: The present study aimed at assessing the association between environmental temperature and the relative humidity of the air with frequency of hypertensive disorders of pregnancy. Methods: A prospective and retrospective, descriptive, ecological study was held at a teaching maternity in Recife, Brazil. Data from all 26.125 pregnant women admitted between 2000 and 2006 were analysed and 5.051 had the diagnosis of hypertensive disorder of pregnancy. The incidence percentages were calculated monthly per deliveries. Data on mean monthly temperature and relative humidity of the air were collected and monthly comparisons were conducted. February was chosen as the reference month due to its lowest incidence of the disease. The relative chance of hypertensive disorders of pregnancy for each other month was estimated by odds ratio and Pearson's correlation coefficient was used to calculate the relation between the incidence of hypertensive disorders of pregnancy and the mean monthly temperature and relative air humidity. Results: February presented the lowest mean monthly incidence (9.95%) and August the highest (21.54%). Pearson correlation coefficient revealed a higher incidence of hypertensive disorders of pregnancy in the cooler months (r= -0.26; p=0.046) and no significant effect of relative air humidity (r=0.20; p=0.128). Conclusion: The incidence of hypertensive disorders of pregnancy may be affected by variations in temperature, increasing during cooler periods.

scholarly journals Performance of different methods for reference evapotranspiration estimation in Jaíba, Brazil

2018 ◽  
Vol 22 (2) ◽  
pp. 83-89 ◽  
Author(s):  
Gustavo H. da Silva ◽  
Santos H. B. Dias ◽  
Lucas B. Ferreira ◽  
Jannaylton É. O. Santos ◽  
Fernando F. da Cunha
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Standard Method ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Air Humidity ◽  
Method Performance ◽  
Relative Air Humidity ◽  
Evapotranspiration Estimation ◽  
Missing Variables

ABSTRACT FAO Penman-Monteith (FO-PM) is considered the standard method for the estimation of reference evapotranspiration (ET0) but requires various meteorological data, which are often not available. The objective of this work was to evaluate the performance of the FAO-PM method with limited meteorological data and other methods as alternatives to estimate ET0 in Jaíba-MG. The study used daily meteorological data from 2007 to 2016 of the National Institute of Meteorology’s station. Daily ET0 values were randomized, and 70% of these were used to determine the calibration parameters of the ET0 for the equations of each method under study. The remaining data were used to test the calibration against the standard method. Performance evaluation was based on Willmott’s index of agreement, confidence coefficient and root-mean-square error. When one meteorological variable was missing, either solar radiation, relative air humidity or wind speed, or in the simultaneous absence of wind speed and relative air humidity, the FAO-PM method showed the best performances and, therefore, was recommended for Jaíba. The FAO-PM method with two missing variables, one of them being solar radiation, showed intermediate performance. Methods that used only air temperature data are not recommended for the region.

scholarly journals Physical model of «substrate-coating» system structuring in complex modification processes of surface layers in working parts of dies and press molds

2018 ◽  
Vol 2018 (11) ◽  
pp. 35-41
Author(s):  
Олег Морозов ◽  
Oleg Morozov ◽  
Валерий Кокорин ◽  
Valeriy Kokorin ◽  
Владимир Табаков ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Physical Model ◽  
Cold Plastic Deformation ◽  
Coating System ◽  
Resistant Steel ◽  
Surface Layers ◽  
Heat Resistant Steel ◽  
Plasma Sputtering ◽  
Ion Plasma ◽  
Wear Coatings

Basic methods to increase durability of die working parts including processes of cold plastic deformation at anti-wear coatings application by a method of ion-plasma sputtering are considered. A physical model of cold plastic deformation of samples made of heat-resistant steel H12M is presented.

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