scholarly journals A Study on the Carbonation Rate of Concrete Exposed in Different Climatic Conditions

2021 ◽  
pp. 128-136
Keyword(s):  
Fly Ash ◽  
Relative Humidity ◽  
Environmental Conditions ◽  
Climatic Conditions ◽  
Climate Conditions ◽  
Industrial Areas ◽  
Carbonation Process ◽  
Carbonation Resistance ◽  
Proper Design ◽  
One Year

Recently, the degradation of concrete has become a serious problem worldwide and one of the principle factors of degradation is the carbonation process. It is well established that environmental conditions affect the carbonation progress of concrete among the most important factors that can greatly affect the carbonation resistance of concrete are relative humidity (RH) and temperature. Carbonation has become a threat to concrete structures, especially in urban and industrial areas. Thus, it is necessary to have a proper design to maintain the structure's stability against degradation caused by carbonation. Therefore, this study was conducted to evaluate the effects of different environmental and climatic conditions on the carbonation rate of concrete. The specimens were prepared using OPC and fly ash (FA). After 28 days of air curing, specimens were exposed to different climate conditions under sheltered and un-sheltered conditions. The carbonation tests were conducted at the ages of 6 and 12 months. It was found that the carbonation rates were significantly influenced by the climate and environmental conditions; the specimens exposed to a relatively dry environment and low annual precipitations have shown higher carbonation during one-year exposure. Moreover, in unsheltered conditions, the annual precipitation significantly affects the carbonation rate of concrete. Furthermore, it was observed that a 20% replacement of FA does not enhance the carbonation resistance of concrete.

THE CROSS-VENTILATED TUNNEL SMOKEHOUSE

1946 ◽  
Vol 24f (1) ◽  
pp. 81-90
Author(s):  
E. P. Linton ◽  
A. L. Wood
Keyword(s):  
Relative Humidity ◽  
Climatic Conditions ◽  
Steam Consumption ◽  
The Cross ◽  
One Year ◽  
Short Time

A tunnel smokehouse with an output of 3000 lb. of smoked fillets per nine hour day has been in operation about one year. The temperature, relative humidity, and smoke velocity are controlled at optimum values independent of climatic conditions. Hence the colour and shrinkage of the product may be standardized and losses from cooking and dropping of the fish avoided. The relatively short time of smoking of two to three hours reduces spoilage of the fish to a minimum with resulting improvement in quality. Power and steam consumption have been kept as low as feasible.

Neoseiulus baraki (Acari: Phytoseiidae) survival and walking in response to environmental stress

2019 ◽  
Vol 24 (3) ◽  
pp. 487 ◽  
Author(s):  
Vaneska Barbosa Monteiro ◽  
Girleide Vieira França ◽  
Manoel Guedes Correa Gondim Jr ◽  
Debora Barbosa Lima ◽  
Jose Wagner Silva Melo
Keyword(s):  
Relative Humidity ◽  
Environmental Stress ◽  
Survival Time ◽  
Environmental Conditions ◽  
Walking Speed ◽  
Tracking System ◽  
Climatic Conditions ◽  
Stress Factors ◽  
Neoseiulus Baraki ◽  
Increasing Temperature

Living organism is exposed to the influence of various environmental conditions. These environmental conditions can trigger stress and compromise the fitness of the organism. As living organisms, phytoseiid mites are frequently exposed to a range of environmental stressors. In the present study, we attempted to explore the responses of the Neoseiulus baraki to environmental stress factors (temperature and humidity). Initially, the effect of different temperature (18–33 °C) and relative humidity (10–95%) levels on the survivorship of unfed N. baraki females was evaluated. Next, we estimated the walking parameters (distance traveled and average walking speed) with a computerized tracking system and we tested how N. baraki is constrained in their effective displacement by their ability to walk and survive in absence of food. The proportion of surviving N. baraki as well as mean survival time decreased significantly with increasing temperature. The opposite trend was observed to relative humidity. The distance covered by N. baraki reduced with increasing temperature (when only taking the temperature dependence of the survival time but not of walking speed and neither the tortuosity of the walking path) ranged from 550 m at 18 ºC to 100 m at 33 ºC. Under climatic conditions representative for the Tropics (27 ºC and 75 % RH) N. baraki was able to survive up to 1.5 days (36 h) without feeding and covered 0.9 m in 10 min as displacement estimated by walking.

scholarly journals Influence of climatic conditions on productivity and adaptability of Camelina sativa

2020 ◽  
Vol 224 ◽  
pp. 04006
Author(s):  
E L Turina ◽  
T Ya Prakhova
Keyword(s):  
Environmental Conditions ◽  
Steppe Zone ◽  
Camelina Sativa ◽  
Climatic Conditions ◽  
Forest Steppe ◽  
Hydrothermal Conditions ◽  
Middle Volga Region ◽  
Hydrothermal Coefficient ◽  
Climate Conditions ◽  
The Crimea

The purpose of the research is to assess the productivity and adaptability of Camelina sativa depending on the natural and climatic conditions of the forest-steppe zone of the Middle Volga region and the steppe Crimea. The researches were conducted in two regions (Penza and Crimea) with contrasting hydrothermal conditions in 2015–2019 years. Climate conditions in the years of researches were characterized by significant variability in both the degree of humidity and temperature regime in both regions. The hydrothermal coefficient in the Crimea varied in the range of 0.23–1.11, in the conditions of Penza - from 0.45 to 1.10. The index of environmental conditions varied from -0.58 to 1.28 units depending on the natural and climatic zone. On average, in 2015–2019, the productivity of Camelina changed from 1.45 to 1.79 t/ha in Penza and from 0.56 to 1.66 t/ha in Crimea. The highest yield of Camelina sativa was recorded in 2016 in Penza and in 2017 in the Crimea and amounted to 1.79 and 1.66 t/ha, respectively. The value of the index of environmental conditions is 1.17 and 1.28 with hydrothermal coefficient of 0.82 and 0.61, respectively. Depending on the conditions of the year and the region, the oil content varied from 33.9 to 43.9 %. At the same time, there is a tendency to decrease the amount of oil for all years of study in the direction from the Crimea to the zone of the Penza region. Camelina sativa is characterized by a high level of resistance to stressful conditions (0.49– 1.10), differs in environmental adaptability (bi=1.15–1.17), has a high fitness criterion, 41.2–41.5 g/m2, depending on the region.

Déformations générées dans les bétons sous l'influence des conditions climatiques

1991 ◽  
Vol 18 (6) ◽  
pp. 1088-1092 ◽  
Author(s):  
Gérard Ballivy ◽  
Brahim Benmokrane ◽  
Omar Chaallal
Keyword(s):  
Experimental Study ◽  
Relative Humidity ◽  
Strain Gauge ◽  
Environmental Conditions ◽  
Structural Integrity ◽  
Climatic Conditions ◽  
Strain Gauges ◽  
Volume Changes ◽  
Environmental Agents ◽  
Concrete Blocks

This paper presents the results of an experimental study of strains generated in concrete by variations in climatic conditions. Three 0.16 m3 concrete blocks, instrumented with vibrating wires strain gauges, were exposed to various environmental conditions (drying–wetting) during approximately 3 years and strains were measured. The study shows that concrete strains induced by environmental agents acting alone can reach levels that may jeopardize the structural integrity of concrete structures exposed to similar conditions, when the boundary conditions cannot accommodate the resulting extensive volume changes. Key words: environmental conditions, relative humidity, temperature, drying, wetting, vibrating wires strain gauge, concrete strains.

Drying Shrinkage of Fly Ash-Based Self-Compacting Geopolymer Concrete

2014 ◽  
Vol 567 ◽  
pp. 362-368 ◽  
Author(s):  
M.F. Nuruddin ◽  
F.A. Memon ◽  
N. Shafiq ◽  
S. Demie
Keyword(s):  
Fly Ash ◽  
Relative Humidity ◽  
Drying Shrinkage ◽  
Time Dependent ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Shrinkage Behaviour ◽  
One Year ◽  
Curing Regime

–The drying shrinkage behaviour of fly-ash-based self-compacting geopolymer concrete (SCGC) was studied for a period of one year. Two SCGC and One OPC-based conventional mixture were used in the present investigation. Drying shrinkage test commenced on the 7th day after casting the test specimens. Once the appropriate curing regime was completed, the specimens from each mix were placed in the laboratory room where the temperature was maintained at 23°C, however, the relative humidity of the room varied between 56 and 64 percent. Strain readings taken at specific intervals were analyzed to determine the time-dependent deformations of each mixture. Test results indicated that the heat-cured fly ash-based SCGC experienced very low drying shrinkage than that of water-cured OPC based concrete. After one year of exposure, in comparison to 466 με, the value experienced by OPC concrete, the drying shrinkage strains of SCGC mix specimens ranged between 141 and 159 με. These values were about 65-70% lower than that of OPC concrete. It is anticipated that the findings of this investigation would help in predicting the behaviour of SCGC. Keywords-Fly ash, Geopolymer concrete, Self-compacting Geopolymer concrete, Drying shrinkage

scholarly journals Critical Performance Aspects of Retrofitting Apartment Buildings Using a Multifunctional Façade System

Buildings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 184
Author(s):  
Paiho ◽  
Ojanen ◽  
Seppä ◽  
Paavola
Keyword(s):  
Climatic Conditions ◽  
Market Potential ◽  
Safe Operation ◽  
Climate Conditions ◽  
Apartment Buildings ◽  
European Climate ◽  
Northern European ◽  
Hygrothermal Performance ◽  
Proper Design ◽  
Performance Challenges

There is huge market potential for energy refurbishment solutions in European buildings. This paper analyzes the challenges related to using a multifunctional energy efficient façade system, the “Meefs” system, in retrofitting multi-family apartment buildings. Similar challenges often occur also in other comparable façade renovation solutions. The focus is on hygrothermal performance even as other aspects are also discussed. After introducing the hygrothermal performance challenges of the Meefs system, numerical case analyses are performed in three different climatic conditions. The results for 26 cases are presented. A core result is that the drying of any exterior renovation system is mandatory to guarantee safe operation in different European climate conditions. This emphasizes proper design needs in all climates. Based on the analyses, design recommendations can be given for the Meefs system. In Central and Northern European climates, the system contains challenges which may hinder implementation in practice.

scholarly journals Effect of Extreme Climate on Topology of Railway Prestressed Concrete Sleepers

Climate ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 17 ◽  
Author(s):  
Dan Li ◽  
Sakdirat Kaewunruen
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Prestressed Concrete ◽  
Vital Role ◽  
Climatic Conditions ◽  
Time Dependent ◽  
Railway Infrastructure ◽  
Time Dependent Behaviour ◽  
The Impact ◽  
Dependent Behaviour

Railway networks are exposed to various environmental conditions. It is thus critical that infrastructure components can tolerate such effects by design. Railway sleepers are a critical safety component in ballasted track systems. Prestressed concrete is currently the most common material for railway sleepers due to its superior advantages in structural performance, low maintenance, sustainability, and construction. In practice, many prestressed concrete sleepers are installed in harsh environments that are subject to various changes in climate. Environmental conditions are, therefore, one of the most critical phenomena affecting the time-dependent behaviour of prestressed concrete sleepers. Hence, the impact of climate changes on the serviceability of railway infrastructure needs to be thoroughly investigated. Temperature and relative humidity are crucial aspects that have not been sufficiently studied so far with reference to prestressed concrete sleepers embedded in track systems. This study aims to investigate the effects of extreme climatic conditions on the performance and time-dependent behaviour of prestressed concrete sleepers using contemporary design approaches. The issue concerning the effects of climate uncertainties on creep and shrinkage is rigorously investigated on the basis of both environmental temperature and relative humidity. The outcome indicates that environmental conditions play a vital role in the time-dependent behaviour of prestressed concrete sleepers. The insights will be essential for assessing the long-term serviceability of prestressed concrete sleepers that have been installed in railway lines and are subjected to extreme environmental conditions.

Relationship between the excretion of protostrongylid larvae in sheep in North-west Spain and climatic conditions

1994 ◽  
Vol 68 (3) ◽  
pp. 197-201 ◽  
Author(s):  
P. Díez-Baños ◽  
P. Morrondo-Pelayo ◽  
A. Feijoo-Penela ◽  
B. Carrillo-González ◽  
C. López-Sández
Keyword(s):  
Relative Humidity ◽  
Linear Regression ◽  
Climatic Factors ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Statistical Correlation ◽  
Climatic Conditions ◽  
Intensity Of Infection ◽  
North West ◽  
One Year

AbstractThe relationship between different climatic factors (temperature, relative humidity and rainfall) and the pattern of lungworm larval excretion was studied in sheep under a continuous grazing pattern in North-west Spain, where the climate is intermediate between sub-humid Mediterranean with an Atlantic tendency and European Atlantic. Over a period of one year, 44 animals were sampled once a month at random from a flock of 80 Galician breed sheep, all over 4 years old. Faeces were taken directly from the rectum and the number of first stage larvae per gram of faeces was determined for each animal, and the species of Protostrongylidae (Nematoda) identified. Larval excretion was irregular during the study. The prevalence and intensity of infection were greater in the colder months (40.9%; x=12.3 ± 40.4) and less in the warmer months The species of Protostrongylidae identified and prevalences (%) were Neostrongylus linearis (71.5), Muellerius capillaris (18.8) and Cystocaulus ocreatus (9.7). Between November and March, with low temperatures, the prevalence and intensity of parasitism with N. linearis and M. capillaris were greater than in the months with high temperatures (May to September). Multiple linear regression analysis showed statistical correlation between temperature, relative humidity and rainfall considered together and the number of N. linearis larvae per gram of faeces. Linear regression showed a correlation between the temperature and the percentage of sheep that passed M. capillaris. In general, the prevalence and intensity of infection of the sheep with N. linearis, M. capillaris and C. ocreatus larvae decrease when the temperature increases and increase when the relative humidity and rainfall increases.

scholarly journals Effect of Environmental Conditions on Performance of Corrugated Sheet Boxes Manufacturing Process

2019 ◽  
Vol 8 (2S7) ◽  
pp. 339-343
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Environmental Conditions ◽  
Performance Test ◽  
Mechanical Performance ◽  
Sheet Material ◽  
Climatic Conditions ◽  
Atmospheric Conditions ◽  
Severe Condition ◽  
Moisture Content Level

Corrugated sheet material is very sensitive to the environmental conditions, especially moisture. The present study focuses on the mechanical behavior of corrugated sheet box board at different humidity and temperature conditions. The objective of this study is to study the important properties of corrugated sheet boxes at different climatic conditions and also to study the influence of the properties of corrugated sheet paper on the properties of corrugated board and box at various environmental conditions. The mechanical performance test carried out under controlled atmospheric conditions where the temperature (0C) range was studied from 200C to 500C and the relative humidity (Rh) range was studied from dry condition 30% Rh to severe condition 90% Rh. The results tested showed that the maximum compressive load of empty corrugated sheet box sealed exposed to moisture content decreased with the increase of temperature and relative humidity. In general it is observed in paper, corrugated sheet board and boxes that have optimum combined properties are obtained at moisture content level at 7-8% and hence moisture content of 7-8% may be the ideal value for corrugated sheet paper used in corrugated packaging industry

scholarly journals PERFORMANCE ANALYSIS OF ALTERNATIVE COVERINGS FOR COOLING TOWERS IN BRAZILIAN CAPITALS THROUGH NUMERICAL MODELING

2017 ◽  
Vol 16 (2) ◽  
pp. 67
Author(s):  
A. C. C. Tomás ◽  
P. H. Souza ◽  
A. R. M. Primo
Keyword(s):  
Relative Humidity ◽  
Cooling Tower ◽  
Waste Heat ◽  
Heat Removal ◽  
Poor Performance ◽  
Climatic Conditions ◽  
Capital City ◽  
Inlet Temperature ◽  
Cooling Towers ◽  
Climate Conditions

A cooling tower is a heat removal device used to transfer waste heat to the atmosphere process. Today, commercial cooling towers use plastic coverings, specially developed for this application. It is known that alternative coverings have been an increasingly viable solution thanks to its performance and cost. The purpose of this study was to evaluate, through numerical simulation, the performance of different alternative coverings under different climatic conditions. Therefore, we used, as reference, the climate of the state capitals and their respective geographic regions. The performance of these coverings was evaluated through observation of three parameters: effectiveness, approach and cooling. The main input data used by the software EES (Engineering Equation Solver) for the calculation of evaluation parameters were: experimental NUT of each covering, average local temperature, local air pressure and relative humidity. The flow of water and air were set at 0.33 L / s and 170 L / s, respectively. We concluded that the air inlet temperature and relative humidity at each location greatly influence the performance of the coverings. The alternative covering that showed the best results was the "cross-fiber and neck", with an efficiency about 35% lower than the industrial covering. The Brazilian capital city with the best performances for alternative coverings was Palmas (TO). This is due to the very low relative humidity found in the city in the summer. Air humidity is also responsible for the poor performance of coverings in the capitals of the North. In general, the region with the best performance was the South, due to the characteristics of the sub-tropical climate. Regions that had the worst results were North / Northeast because of the weather that combines high temperatures with high / moderate humidity, respectively. Thus, the study of climate conditions is indispensable for the operation prevision of a cooling tower. Alternative coverings will be viable depending on the location.

Sign in / Sign up

Export Citation Format

Share Document