Effect Of Rainwater Research Articles

The Effect of Rainwater in Concrete Mixture on Concrete Compressive Strength

The Effect of Rainwater in Concrete Mixture on Concrete Compressive Strength

Vertical Capillary Barriers and Wick Drains to Mitigate the Rain-induced Slope Failures: Numerical Analysis

Slope failures are catastrophic when they suddenly occur in human habitats. The stability of slopes gradually diminishes with heavy rainfall due to the increase in pore water pressure; subsequently, the shear strength of the slope soil decreases. The effect of rainwater on the instability of slopes was studied in this research with respect to factor of safety values. Accordingly, finite element analysis and limit equilibrium analysis were conducted using a 2D model of a soil slope in SEEP/W and SLOPE/W programs to observe the responses of the slope soil profile under heavy rainfall. Movement of the wetting front and the fluctuation of the groundwater table were studied to develop a drainage mechanism, thereby to control the effect of infiltrated rainwater on slope failure. A conceptual method was introduced in this study by developing a numerical model with an effective drainage system which consists of vertical capillary barriers with combination of horizontal wick drains in a cascade manner in the slope. This method exhibited high stability of the slopes even with continuous rainfall for number of days, therefore, applicable as a sustainable prevention method of slope failures.

The interaction between rainwater and polished building stones for flooring and cladding - Implications in architecture

Stone polishing is a process executed to make the surface glossy, so that the material shines by reflecting the light. The polishing is mainly carried out in flooring and façade cladding to improve the aesthetic properties of the stones. In particular on calcareous stones, polishing is not a permanent feature because various atmospheric agents in outdoor (e.g. rain, freeze and thawing cycles, UV solar radiation) are responsible for weathering with the loss of the mirror-like effect.In this paper, the effects of rainwater on polished limestones used for building cladding have been shown.In order to better reproduce the environmental conditions in building location, two samples horizontally and vertically oriented (simulating flooring and façade cladding respectively), were subjected to rainwater wetting. Other two samples with the same previous orientations were subjected to tap water wetting. After a month test it has been demonstrated how rainwater, differently to tap water, causes micro-corrosion on the samples surface by a modification of the colour and a decreasing of the gloss. This is attributable to a roughness increase. The corrosion intensity depends on the orientation of the samples. The reason of this corrosion is the capacity of the rainwater (with a low saline content) to easily dissolve air carbon dioxide by forming corrosive carbonic acid with respect to high saline content tap water.

The function of floral orientation in bluebells: interactions with pollinators and rain in two species ofMertensia(Boraginaceae)

Pollinators are traditionally considered to be the primary agent of selection on floral traits. However, floral traits may also be under selection from abiotic agents (e.g. rain), which makes considering the relative importance of pollinators and abiotic selective agents on floral traits essential. The functional significance of floral orientation is often ascribed to pollinator attraction, but orientation can also protect reproductive structures from rain. Therefore, a study that incorporates both factors will enhance our understanding of the ecological roles of floral orientation in plant fitness. Mertensia brevistyla and M. fusiformis are herbaceous species that differ in their floral orientations. A series of field and laboratory experiments was used to investigate the adaptive function of floral orientation in these species, particularly with respect to pollinators and rain. We measured and compared floral orientation and visitor assemblages between M. brevistyla and M. fusiformis populations in western Colorado, USA. We manipulated floral stems and conducted a choice experiment with floral visitors, and also compared orientations of pollinator-visited stems with those of unvisited stems in a natural setting. We examined pollinator- and rain-mediated selection on floral orientation by manipulating orientation, conducting supplemental pollinations, applying watering treatments and measuring subsequent seed set. We also experimentally tested the likelihood of rain contact with anthers, and the effect of rainwater on pollen germinability. Mertensia brevistyla had a significantly more upright floral orientation than M. fusiformis, and seed set was highest in upright M. brevistyla and in horizontal/pendant M. fusiformis stems, supporting an adaptive function (via female fitness) of the interspecific difference in orientation. However, floral visitor assemblages did not differ significantly between the two species; visitors did not exhibit significant preference for either orientation; and pollinator-mediated selection on orientation was undetectable. Similarly, there was little effect of water on seed set in either species, regardless of floral orientation. However, pollen germinability was reduced in both species by immersion in water; and water was more likely to contact anthers in M. fusiformis than in M. brevistyla, due to interspecific differences in floral morphology. We conclude that pollinators are likely not the primary selective agent driving differences in orientation in these Mertensia species. Instead, the negative effect of rain on pollen germinability helps explain the more pendant orientation of M. fusiformis, while short anthers in more upright M. brevistyla provide an alternative adaptation to rain. The selective agent driving effects of orientation on seed set remains unclear. This study illustrates the necessity of considering male fitness and abiotic agents in interpreting the functional significance of inflorescence traits.

Moisture and temperature effects on rocks materials and natural erosion energy

Materials interact with pollutant in a very complex manner, the possibility of erosion, adsorption, desorption, transportation, deposition, and phase change will appear because of the interaction between the pollutant and the material surface. The effect of many other environmental effects also appear, like the effect of rain water in breaking away tiny rock particles (grit productivity). All the actions mentioned or any one of them may causes high damage or weaken the structure. This research highlights the importance of specific physical properties and material weakness, the effect of specific environmental factors (humidity, rain, and temperature) on materials, such as building materials and the potential occurrence places of cracks in the material, by knowing the quality of the material.

Dynamic Response of Curved Wall LTSLS Under the Interaction of Rainwater Seepage and Earthquake

When water permeates the loess, the strength of the loess will be greatly reduced; thus, it is necessary to study the effect of seepage on the seismic response of a loess tunnel. Fields of structure and fluid are simulated using ADINA, and the calculation model of a curved wall loess tunnel with a super-large section (LTSLS) is established. Rainwater is simulated using an incompressible constant parameter model. Considering the action of near- and far-field earthquake and pulse effects, the Galerkin method is used to solve the interaction of stress and seepage fields. By contrasting and analyzing the maximum principal stress, the minimum principal stress, the maximum displacement of lining and the internal force of the tunnel structure, the influence of rainwater seepage on the mechanical properties of LTSLS is studied, and meanwhile, dynamic responses of LTSLS under the interaction of rainwater seepage and earthquakes are studied. The results show that if rainwater seepage is only considered for shallow buried LTSLS, the pore water pressure of a tunnel is so small that it may be neglected. The damage degree of LTSLS under the interaction of rainwater seepage and earthquakes is more than that under a single field. When considering the interaction effect of rainwater and earthquakes, the pore water pressure, principal stress and displacement under a near-field earthquake with pulse effect are greater than those under a near-field earthquake without pulse effect and a far-field earthquake under the same condition.

Effects of Rainfall in Kunming on the Growth and Alkaline Phosphatase Activity of the Cyanobacterium Microcystis aeruginosa

The effects of rainwater on freshwater ecosystems have received increasing attention worldwide. Alkaline phosphatase activity (APA) affects the biochemical cycles of phosphorus in the water, thereby affecting the proliferation and outbreak of cyanobacteria blooms. However, it is still unclear whether the complex composition of rainwater has a significant effect on the alkaline phosphatase activity. In this study, the effects of rainfall on Microcystis aeruginosa in Kunming were evaluated based upon changes in alkaline phosphatase activity, algal growth, and chlorophyll a. The results showed that the addition of rainwater brought about different changes in alkaline phosphatase activity, algal growth, and chlorophyll a. The general trend showed that a certain amount of rainwater (equivalent to light, moderate rain, and heavy levels) had a positive effect on the alkaline phosphatase activity, algal growth, and chlorophyll a in the cultivation system. Therefore, the following preliminary inference can be drawn: in the Kunming area, a certain amount of rainwater may promote the growth of blue-green algae, exacerbating an outbreak of cyanobacteria blooms.

Elemental concentration in deposited dust on urban tree leaves depending applied washing method

In our study, the concentrations of elements were determined in leaves and deposited dust of Quercus robur and Celtis occidentalis which were washed with distilled water, rainwater and tap water. According to our results, each washing solutions had a significant effect on the elemental concentrations in the foliage dust. The highest concentrations of aluminum, chromium, copper, iron, manganese and zinc were detected in the foliage dust which was washed down with rainwater. The highest strontium and barium concentrations were found in the foliage dust which was washed down with tap water. We observed chromium and manganese accumulation in Q. robur leaves, while the concentrations of barium, copper and strontium were the highest in C. occidentalis leaves. Our results demonstrated the effect of rainwater on tree leaves which phenomenon occurs naturally. Rainwater may wash down the dry deposited foliage dust from the leaf surface, but it also delivers a certain concentration of elements through wet deposition.

N- and P-addition inhibits growth of rich fen bryophytes

A greenhouse experiment was set up to investigate if infrequently and frequently occurring species respond differently to simulated habitat changes. Two frequently occurring (Bryum pseudotriquetrum and Calliergonella cuspidata) and two infrequently occurring (Hamatocaulis vernicosus and Paludella squarrosa) rich fen bryophytes were grown in mixed culture and subjected to rainwater or groundwater and three levels of N, ammonium nitrate (0, 1 and 3 mg N L–1) and P, potassium phosphate (0, 0.05 and 0.1 mg P/L). All species responded negatively to higher N-levels and three of the four species responded negatively to rainwater and higher P-levels. C. cuspidata had highest relative growth rate (RGR) in all treatments, and the infrequently occurring species had lower RGR and were more negatively affected by high levels of N than the frequently occurring species. A negative effect of rainwater seemed to be caused by higher background levels of N in rainwater compared to groundwater. We found a negative effect of high initial bryophyte density in three of the four species indicating density-dependent inhibition between species. We suggest that maintenance of oligotrophic conditions by recharge of nutrient-poor groundwater is vital for conservation of infrequently as well as frequently occurring rich fen bryophytes.

Effect of Rainwater and Seawater on the Permittivity of Denim Jean Substrate and Performance of UWB Eye-Shaped Antenna

The effect of rainwater and seawater on the permittivity of denim jean substrate and performance of an ultrawideband (UWB) eye-shaped textile antenna is investigated in this letter. For the simulated and measured reflection coefficients in dry condition, it was found that the antenna operates at 2.4-10.9 and 1.6-12 GHz, respectively, with the simulated gain between 3.2 and 5.8 dBi from 2 to 12 GHz with efficiencies greater than 50%. The antenna can operate at the entire range in dry conditions when S11 ≤ -10 dB, but with limited performance under wet conditions. However, it cannot be used when immersed in rainwater and seawater. From the investigation, it can be shown that the permittivities of denim jean substrate under wet and immersed conditions are proportional to the permittivities of the absorbed medium (rainwater or seawater) at 2-12 GHz.

Embankment Settlement Calculation Based on the Unsaturated Soils Theory

Based on the one-dimensional constitutive relationship of unsaturated soils, this thesis has established the calculation model for embankment settlement with lateral deformation and without lateral deformation in accordance with the mechanic characteristics and in consideration of the influence of water environment. In addition, the thesis has provided the calculation methods for embankment settlement under various working situations (like under the situations of external load function, self-weight effect, increasing of the groundwater level, the invasion effect of rain water and the comprehensive effect of various working conditions) and used the settlement deformation results from the experiments of embankment models to check the calculation method. The method put forward in this thesis could not only be used in the calculation of the settlement deformation under load, but also could be used for the calculation of the deformation caused by the changes of water content in the embankment.

Reason Analysis of Landsliding for the Side Slope Corner Area

Deformation amount is depended on area position for approximate condition on engineering geology. Deformation amount is small as radius of curvature become small, conversely large. This paper studies severe plastic deformation reason of slope body. Landsliding reason of the side slope corner area is the rain soaked softening effect for the lower part of the clay rock special slope form. Therefore, abnormal deformation is produced. Slope stability is related slope angle, sometimes related secondary softening effect of rain water. So, key measures of slope safety are ensured for controlling the rain soaked softening effect.

Moisture Damage in Vented Air Space of Exterior Walls of Wooden Houses

Abstract Most of the exterior walls of wooden houses in Japan have a vented air layer between the exterior cladding and the insulation. This vented air layer is designed to dehumidify the exterior walls by discharging humidity to the outside and allowing outdoor air to enter, thereby decreasing the risk of condensation on the exterior wall during winter. It is assumed that the source of this moisture is the indoor air, and that the outdoor air is drier. However, the outdoor air is often highly humid during the rainy season and may become a source of moisture. The vented air layer also allows rain water to drain away. Any rain water penetrating through the exterior cladding is drained away through the vented air layer. However, rain can also enter the vented air space through the air inlets. Since it takes a certain amount of time for all the rain water to drain away, water may accumulate in the vented air layer and produce high humidity in the exterior wall. In order to evaluate the effectiveness of an exterior wall with a vented air layer, its hygrothermal characteristics should be investigated, taking the effect of rain water into consideration. This paper describes a case of moisture damage where stain appeared on the outer surface of the plywood wall in a wooden residential building. Experiments were carried out in climate chambers to clarify the conditions that are causing stain. Hygrothermal conditions in the vented air layer were simulated using heat, air, and moisture model, and the causes of staining were investigated.

The Effect of Rainwater and Cultivated Areas on Grain Crop Production in Sulaimani Governorate During 1982-2002

The Effect of Rainwater and Cultivated Areas on Grain Crop Production in Sulaimani Governorate During 1982-2002

Pollutants in Rainwater Runoff in Korea: Their Impacts on Rainwater Utilization

Frequent urban floods and insufficient water supply have led to developing technologies for rainwater utilization in order to buffer extreme runoff situations in the watercourses and to provide an ongoing water supply for non-potable use. However, little information is available on the water qualities and runoff properties of collected rainwater in connection with efficient design and maintenance strategies of rainwater utilization systems. In this work, the characteristics of rainwater were investigated in a full-scale rainwater utilization facility in Korea. Samples of runoff rainwater from various catchment surfaces were analyzed for physico-chemical and microbial determinants including metals, nutrients, pH, turbidity, conductivity, and microorganisms. The pollutant concentrations in rainwater storage tank were also monitored to elucidate the impact of input rainwater quality on stored water property. It is likely that particles and total coliforms are major issues in operating rainwater utilization system. However, further studies will be necessary to address the health effect of rainwater in terms of microbial and ecotoxicological measures.

The ancient Kamirian water storage tank: A proof of concrete technology and durability for three millenniums

This paper presents the research work conducted on a concrete specimen cut from a manmade underground hydraulic structure with respect to a well-preserved water storage tank which was discovered from the archaeological excavations in the area of the ancient city of Kamiros. During Antiquity, this city was the largest of the three most important cities of the Greek island of Rhodes, where for millenniums civilisation flourished in all its expressions and forms. The research concerns physical, chemical and mechanical tests carried out on the concrete sample. The results derived show this concrete's good durability despite the dissolving effect of rainwater and of the humic acid's activity for roughly the past three millenniums. Also, the technological aspects of this concrete reveal that the ancient greeks had an excellent knowledge of concrete technology three millenniums ago.

95/05285 Effect of rainwater on the remobilization and dissolution of 134Cs and 85Sr contained in aerosol similar to those discharged in a nucl

95/05285 Effect of rainwater on the remobilization and dissolution of 134Cs and 85Sr contained in aerosol similar to those discharged in a nucl

Effect of rainwater on the remobilization and dissolution of 134Cs and 85Sr contained in aerosols similar to those discharged in a nuclear accident and deposited in an urban environment

An accident in a PWR could lead to discharge of radioactive aerosols into the atmosphere. The present study consisted of establishing, under laboratory conditions, how the caesium and strontium contained in such aerosols are remobilized by rainwater after dry deposition in an urban environment. Aerosols representative of those discharged in a PWR accident were generated and deposited on five building materials used in France. A rainfall simulator was used to provide varying intensities of rain. The percentages remobilized, both as particles and dissolved in rainwater, were then measured. Remobilization is dependent on the nature of the material, the radioelement and the intensity of the rain. It varies from 5 to 60% for caesium and from 5 to 30% for strontium. Remobilization increases as rain intensity decreases. Caesium is mainly remobilized in dissolved form while strontium is remobilized in the form of particles.

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystems

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H2SO4 and nitrate, and rain water containing ammonium sulphate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulphate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulphate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH=3.8. Under acidified conditions, ammonium sulphate deposition lead to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H2SO4 deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr. The acidification of water appeared to be coupled with changes in alkalinity, sulphate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH3-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulphate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters.

Chemical Aspects of Heather Burning

Heather burning is widely practised by farmers and gamekeepers in most upland regions of Great Britain. The conditions, if any, under which the practice can be regarded as a sound long-term system of management are not known. Pearsall (1950) and McVean (1959) have discussed the dangers associated with burning but little is known about the effects of burning on soil fertility. When a moor is burnt a large proportion of the plant nutrients contained in the standing vegetation is released in more mobile forms in the ash or in smoke. This paper describes an attempt using laboratory experiments to assess to what extent these nutrients are likely to be lost from the plant-soil system. It covers three major aspects of heather burning: the chemical changes which take place when vegetation is burnt; the effects of rain water on the products of burning; and finally the compensating factors that reduce or make good any losses from the system. In these experiments samples of heather were burnt in the laboratory, the resulting ash was extracted under various conditions and the capacity of the soil to retain the soluble nutrients was examined using soil blocks. The composition of the smoke produced during the burning was also determined.