Conditions Of Water Absorption Research Articles

Effect of Hydrothermal Aging on Damping Properties in Sisal Mat-Reinforced Polyester Composites.

Hydrothermal aging is a matter of considerable concern for natural fiber-reinforced polymers; it can alter dimensional stability and induce microcracks and macro strain on the composite structure. This study applied a sorption kinetic model and examined the effects of water on the damping factor of sisal mat-reinforced polyester composites. The experimental data were fitted well using a Boltzmann sigmoid function, suggesting a promising first step toward kinetic water sorption modeling. Additionally, a damping test was carried out using the impulse excitation technique, highlighting the composite material's dynamic response under varying water absorption conditions. The result showed that damping exhibited sensitivity to water absorption, increasing significantly during the first 24 h of immersion in water, then remained steady over time, inferring a critical time interval. An empirical model proved satisfactory with the correlation coefficient for sorption rates and damping of sisal mat polymeric composites.

Spatial Analysis of Water Infiltration Potential in the Miu Watershed of Sigi Regency

Abstract. The sustainable management of the Miu watershed Basin is something that needs to be considered in line with the increasing complexity of environmental sustainability challenges and current water availability, not limited to maintaining the flow of water but need to pay attention to the balance of the ecosystem. Ecosystem conditions that are maintained influence high water absorption capacity, thereby reducing surface water runoff.. This research was conducted in the Miu watershed Basin with the aim of identifying the potential for water absorption, the method used in this study was a scoring method with four parameters, namely soil type, slope, rainfall, and land use. Data analysis was carried out using a Geographic Information System (GIS) approach. The results showed that the water absorption conditions in the Miu watershed Basin were classified as good (8.29%), normal good (73.91%), starting to be critical (14.51%), moderately critical (3.29%), and critical ( 0.00%).

Correction of the thermal conductivity of polyurethane insulation material under freeze-thaw and water absorption conditions and its application

Laying insulation material is an effectively method to deal with the frost damages. In the engineering practice, the insulation material will be exposed to water and freezing-thawing cycles (FTC), and its thermal performance may be change. To clarify the effect of FTC on the thermal conductivity, after the polyurethane (PU) board suffered from different numbers of FTC, both the water absorption and the thermal conductivity were measured, and a correction coefficient was introduced to reduce the difference between the measured and designed thermal conductivities. Besides, the selection of the correction coefficient was illustrated by the designing the insulation layer. The results show that (1) after 300 numbers of FTC, the water absorption can reach 34.5% and the thermal conductivity increases to 0.042 W/(m·K), which are 18.5 times and 1.7 times of those before FTC, respectively. (2) The correction coefficients of the PU board vary from 1.065 to 1.701, the water can amplify the influence of FTC on the correction coefficient. (3) For the Lehua tunnel, it is recommended to increase the insulation layer thickness to 5.50 cm, which is fixed at the surface of the secondary lining. The results can not only help us to understand the deterioration of PU board caused by FTC, but also provide a guideline for designing the insulation layer with the correction of thermal conductivity.

Microstructure, Deformation Characteristics and Energy Analysis of Mudstone under Water Absorption Process

In geological engineering, a series of safety problems caused by expansive mudstone are common, such as slope instability and roadbed up-arch. In this paper, the mineral composition of mudstones in the Xining area was analyzed by X-ray diffraction (XRD), and the microstructural and morphological changes of mudstones after water absorption were observed by scanning electron microscopy (SEM) test to analyze the internal factors and microstructural evolution patterns of water absorption and swelling of mudstones. Based on the microstructural units, the mudstones were defined into two categories, one is N-type mudstone with flat sheet-like stromatolite units, and the other is SN-type mudstone with more clastic particle units. Water absorption experiments were conducted on the rock samples to study the microstructure of these two types of mudstones under different water absorption conditions. The pore characteristics of the mudstones were analyzed by using Image-Pro Plus to reveal the water absorption mechanism. The results show that the pore area of N-type mudstone is smaller, as well as the distribution of pore diameter. The pore area of N-type mudstone develops rapidly, in the early stage of water absorption, lots of pores are produced, and the pore area of SN-type mudstone shows an overall decreasing trend. The pore area and the number of SN-type mudstones are at a low level after full water absorption. Under the condition of full immersion, water enters the pores rapidly and soluble salts are dissolved in large quantities. The change of water absorption rate of mudstone with time can be divided into the stage of sudden increase, decrease and stability of water absorption rate. Then, based on the stress theory, the relationship between the macroscopic expansion process and the microstructure of mudstone was analyzed. Finally, the energy basis of mudstone water absorption is discussed. In the swelling of mudstone, the energy gradually turns into swelling strain energy.

Moisture diffusivity, hardness, gelatinization temperature, and thermodynamic properties of ultrasound assisted soaking process of cowpea

AbstractThis study describes the combined effect of ultrasound and temperature on water absorption of cowpea kernel during soaking process. The process was made at 30, 40, 50, 60, 70, 80, and 90°C in water absorption conditions named control (without ultrasound) and ultrasound treatment (40 kHz, 200 W; 50% and 100% amplitude). Fick's second diffusion model for water absorption and asymptotic first order texture model for hardness together with Arrhenius and Eyring–Polanyi approaches were successfully used to evaluate effective moisture diffusivity coefficient (Deff), texture degradation coefficient (kF), gelatinization temperature, and thermodynamic properties of cowpea during soaking process. The models fitted the experimental data satisfactorily with R2 > 0.99, RMSE < 0.09 and X2 < 0.0137. Ultrasound treatment (50% and 100% amplitudes) and temperature increased significantly (p ≤ .05) the Deff and kF of cowpeas during soaking process. Average gelatinization temperature of cowpea from the Fick's and Asymptotic first order texture models together with Arrhenius equations was found as 68.5°C. Negative values of enthalpy, entropy, and increase of Gibbs free energy changes with increasing temperature and ultrasound treatment confirming the effect of temperature and ultrasound on effective moisture diffusivity of cowpea during soaking. Moisture content, harness, Deff, kF and thermodynamic properties of cowpea during soaking process were affected by both the temperature and ultrasound amplitude, which means shortening the soaking and cooking time of cowpea.Practical applicationsThe results of this study could be assisted to industrial producers of cowpea in understanding of heat and mass transfer phenomena during ultrasound‐assisted hydration process of cowpea kernel in soaking, cooking, wet milling, fermentation, formulation of meals, and storage processes.

Characterization and prediction of rutting resistance of rock asphalt mixture under the coupling effect of water and high-temperature

In recent years, the use of rock asphalt as modifier has attracted research interests because of the advantage in improving the thermal stability of asphalt mixture, which is conducive to the rutting resistance of asphalt pavement in high-temperature regions. However, due to a large rainfall in most of high-temperature regions (e.g., China southeastern coastal areas and south China areas), the high-temperature effects and water effects explain interdependently the rutting decay of rock asphalt mixture, which is neglected in existing studies. It is necessary to investigate the coupling effect of high-temperature and water on the rutting resistance of rock asphalt mixture. In response to the above questions, water saturated characteristics of rock asphalt mixture at high-temperature are investigated to determine the water absorption conditions via a new index, namely the water saturated ratio. Moreover, a total of sixty groups of modified wheel tracking tests for rock asphalt mixtures are implemented to reveal the coupling effect of water and high-temperature on the rutting resistance with the change of water conditions, temperatures and rock asphalt dosages. The temperature and water play an important role in the rutting resistance of rock asphalt mixture. Finally, a Bayesian approach for modelling the dynamic stability is also established to predict the rutting resistance of rock asphalt mixture and evaluate the effect degree of different factors.

Водный баланс карстовых областей Кубы

The process and conditions of karst formation and its types have already been studied. As this natural phenomenon is heterogeneous and changeable, it is rather difficult to estimate how karst influences the river runoff, infiltration capacity and water balance in catchment areas. This study is based on the approach used by the author in his researches on water balance. The approach helps to estimate how karst influences infiltration capacity. The study is also based on the genetic runoff theory, firstly introduced by A.N. Befany. This theory takes into account the conditions of water absorption into soil when considering water balance. That is why it suggests three types of absorption: seepage within the period of water formation RT, seepage after termination of runoff due to amounts of water which are left in depressions R0, seepage within the period of runoff recession after water formation RT. In order to consider the influence of karst on hydrological characteristics, this study uses the values of surface detention depth after termination of runoff due to amounts of water left in depressions R0. This parameter is the key parameter in this study as it helps to estimate the influence of caverns on infiltration capacity. However, the amount of water detained in closed depressions R0 can partly include both surface runoff and water detained in caverns. This study helps to distinguish these two types of water. The article also shows the graph dependence between the cavern volume filled with water and infiltration capacity. This dependence makes it possible to estimate how karst influences infiltration capacity and runoff and water balance as well. The analysis helps to determine quantitative influence of karst on infiltration capacity. The results of the research must be considered as preliminary ones as it is necessary to analyze more catchment areas, using observation data from the Pinar del Rio and Matanzas provinces.

Analisis Tingkat Resapan Air Menggunakan Sistem Informasi Geografis di Das Tabunio

The development of development that is so rapid causes more and more land to change into new buildings and settlements that have an impact on the reduction in the area of water catchment areas. Reduced water catchment areas will result in reduced groundwater reserves and will cause natural disasters such as floods. Based on this, efforts need to be made to determine the condition and distribution of water absorption in the Tabunio watershed area. In determining water absorption conditions there are four parameters, namely soil type, rainfall, land cover and slope. The data analysis method used is the overlay method with Geographic Information System (GIS) software. The results of data analysis showed that the study area with an area of 62,558.56 ha was divided into five conditions for water catchment areas. The water recharge conditions were very critical with an area of 32.38 ha, critical conditions covering 13,391.14, rather critical conditions covering an area of 35,769.47 ha, critical conditions ranging from 13,359.27 ha and natural normal conditions covering an area of 6.10 ha.

Determination of reasonable displacement of washing for water injection well

As the oilfield enters the development phase of extra-high water content, it is an important precondition to ensure the steady and steady production of the oilfield. Water injection wells washing wells become one of the most important conventional measures to maintain the water absorption capacity of the formation and improve the water injection effect. In this paper, we determined the well flushing displacement in the field flushing operation. We think that different well flushing operation methods for different strata, pressure, permeability and water absorption conditions can effectively improve the well flushing effect of water injection wells, It solves the problem of frequent job re-allocation due to sand burial of sand produced in the formation, reduces the starting pressure of water injection well and preconditions for casing protection.

Conditions of Water Absorption into Soil and Its Infi ltration into Ground Waters at River Basins of Eastern Cuba

The rivers of Eastern Cuba are characterized by small size, different orography, and moistening. Theoretical aspects of the conditions of absorption formation, values of absorption and infi ltration up to the level of the ground water in the river basins of Eastern Cuba are analyzed with the use of the genetic runoff theory and the linear-correlation model. The dependence of the absorption layer from the geomorphological factor makes it possible to distinguish the layer of surface detention from the general absorption layer before the beginning of water formation (the formation of gravitational water) and during the runoff. The dependence of the infiltration layer from the absorption layer turns out to be rather reliable. However, there is some value on the axis of the infiltration layer which characterizes the presence of the hidden infiltration layer when there is no absorption. It is supposed that in this case the surface and underground catchments are distinguished and there is water exchange between separate subterranean flows.

Accelerated testing for long-term fatigue strength of various FRP laminates for marine use

The prediction of long-term fatigue life of various FRP laminates combined with resins, fibers and fabrics for marine use under temperature and water environments were performed by our developed accelerated testing methodology based on the time–temperature superposition principle (TTSP). The five kinds of FRP laminates were prepared under three water absorption conditions of Dry, Wet and Wet + Dry after molding. The three-point bending constant strain rate (CSR) and fatigue tests for these FRP laminates at three conditions of water absorption were carried out at various temperatures and loading rates. As results, the mater curves of fatigue strength as well as CSR strength for these FRP laminates at three water absorption conditions are constructed by using the test data based on TTSP. It is possible to predict the long-term fatigue life for these FRP laminates under an arbitrary temperature and water absorption conditions by using the master curves. The characteristics of time, temperature and water absorption dependencies of flexural CSR and fatigue strengths of these FRP laminates are clarified.

Accelerated testing for long-term strength of innovative CFRP laminates for marine use

We have proposed the accelerated testing methodology for the long-term durability of polymer composites based on the time–temperature superposition principle (TTSP) to be held for the viscoelasticity of polymer matrix. In this paper, the prediction of long-term strength of CFRP laminates for innovative marine use under water absorption conditions were performed by our developed accelerated testing methodology. Three kinds of CFRP laminates employed were conventional plain fabric T300 carbon fibers/vinylester, flat yarn plain fabric T700 carbon fibers/vinylester and multi-axial knitted T700 carbon fibers/vinylester for innovative marine use as a lightweight CFRP ship structures. These CFRP laminates were prepared under three water absorption conditions of Dry, Wet and Wet + Dry after molding. The three-point bending constant strain rate (CSR) tests for three kinds of CFRP laminates at three conditions of water absorption were carried out at various temperatures and strain rates. As the results, the master curves of CSR strength for these CFRP laminates at three water absorption conditions are constructed by using the test data based on TTSP. Furthermore, the time–temperature–water absorption superposition principle (TTWSP) hold for the flexural CSR strengths for these CFRP laminates. Therefore, it is possible to predict the long-term strength for these CFRP laminates under an arbitrary temperature and water absorption conditions using the master curves. It is cleared from the master curves that the degradation rate of CSR strength of these CFRP laminates is determined only by increasing of time, temperature and water absorption and is independent upon the type and weave of carbon fibers.

Mechanisms of Absorption of Inorganic Mercury from Rat Small Intestine. IV: Effect of Chelating Agents and Cysteine on Absorption of Mercuric Chloride in Situ and in Vitro

The effects of chelating agents (citric acid, tartaric acid, penicillamine and ethylenediaminetetraacetic acid) and cysteine on the absorption of HgCl2 were investigated in rats. Perfusion of the small intestine showed that the chelating agents and cysteine decreased the absorption of HgCl2 depending on their stability of constants with Hg2+, under the predominant conditions of water absorption and secretion. The difference in absorption of HgCl2 between both conditions was inversely correlated with their logarithmic stability constant values. These agents decreased the transport of HgCl2 through the everted intestinal wall and the uptake of HgCl2 by the intestinal brush border membrane in a similar manner. From these results, it is suggested that the chelating agents and cysteine decrease the absorption of HgCl2 through the pores of the brush border membrane due to the solvent drag effect.

A new bond failure wire crater in surface mount device : H. Koyama, H. Shiozaki, I. Okumura, S. Mizugashira, H. Higuchi and T. Ajiki. Proc. IEEE/IRPS, 59 (1988)

In the Surface Mount Device(SMD) , a new failure wire crater was studied, and defined as peeling off phenomenon of the wire ball from Si substrate or insulator when soldering heat stress is applied. It only occurs when the package absorbs much water before soldering. To analize this phenomena, conditions of water absorption, soldering heat stress, wafer process(metal1ization and insulator materia1s)and assembly process (wire bonding)were investigated. From these results, it is found that the Cratering occurs when the Si nodules of A1-Si metallization give the damage to the insulator at wire bonding. And this Cratering is accelerated by soldering heat stress (Forces of vaporized pressure of absorbed water and thermal expansion of molding compound).

The conditions of water absorption when employing an external absorbent in the microdetermination of carbon and hydrogen

The conditions of water absorption when using an external nitrogen dioxide absorbent in the carbon and hydrogen microdetermination are very critical. Two sources of error are considered and effectively eliminated or reduced to insignificance. The resultant modified procedure has an accuracy of % C ±0.35, % H ±0.25.