Higher Water Absorption Rate Research Articles

Hydrological properties and solar evaporative cooling performance of porous clay tiles

Evaporative cooling from porous building materials is one of the passive strategies used for building energy conservation. In this study, a porous clay tile (PCT) with specific pore size and porosity characteristics was selected as water storage medium. A composite construction, comprising the PCT, a waterproof coating, a cement mortar layer, and a base layer, was manufactured and its performances as an evaporative cooling structure were evaluated. First, the water absorption properties of the tile were characterized using a partial immersion test, from which the water absorption coefficient and the capillary water content were determined. The solar evaporative cooling performance of the composite construction was then investigated using a special wind tunnel, which allowed controlling the temperature, relative humidity, wind velocity, and simulated solar radiation conditions. The porous clay tile exhibits a relatively high water absorption rate, with a water absorption coefficient of 0.3286kg/m2·s0.5. Although the water retaining capacity of the tile (as represented by a capillary water content of 168.7kg/m3) was not outstanding, the composite construction still produced significant evaporative cooling when water was applied on the PCT. In cyclic experiments performed inside the wind tunnel, the energy balance analysis revealed that, even though the shortwave radiation absorbed by the surface of the wet specimen was larger than that absorbed by the dry specimen surface, 80% of the radiation absorbed by the wet specimen was transformed into latent heat flux, which decreased the external surface temperature by up to 11°C and reduced the internal surface heat flux by 67.7%.

Water Flow from Different Solutions During Perfusion of the Functioning Portion of the Small Intestine of the Rats In vivo

Objective: The study of the water flow during perfusion of the functioning portion of the small intestine of male rats in vivo by Ringer solution, glucose and glycine. Methods: The experiments were performed on the functioning portion of the small intestine of the rats in the chronic experiments in vivo without narcosis, pain, stress and operation trauma, formed according method. The concentration of PEG was determined based on modified method colorimetrically on CFC-2MP, λ=465nm. The concentration of glycine was determined using method colorimetrically on photoelectrocolorimeter–CFC-2MP, λ=540 nm. The concentration of glucose was determined colorimetrically on photoelectrocolorimeter–CFC-2MP, λ=625 nm. The concentration of bile was determined colorimetrically on CFC-2MP, λ=480 nm. Results: There were no found the dilution of the perfusate with physiological fluids. There were detected an absorption of water from the Ringer solution, from the 25 mmol/L solutions of glucose or glycine, prepared on the Ringer solution. Water absorption from the Ringer's solution was more than from the solutions of 25 mmol/L glycine or glucose, prepared on the same Ringer's solution. It was shown the periodic character of the secretion of bile into the living small intestine of the rats under physiological conditions. Conclusion: Comparison of water flows in the unclosed functioning portion of the small intestine during the thereof perfusion by solutions of Ringer, glucose, or of equimolar concentration glycine showed that in all cases, regardless of the type of the substrate and presence of primordial physiological fluids in the intestine, water absorption is observed from the perfusion solution. Thus, it shows a high rate of water absorption in the small intestine, exceeding the dilution of the perfusion solution.

Determination of Moisture Levels, Protein and Water Absorption of Chicken Giblets

This study aimed at evaluating the levels of moisture, protein, water to protein ratio, and water absorption during chilling of chicken giblets (heart, liver, and gizzard) to set legal limits of water absorption during this process. The survey was conducted in the southern Brazil, the largest broiler-producing region of this country. Giblets (heart, liver, and gizzard) were collected fresh from the processing line after evisceration and at the exit of the chiller after the immersion process from two processing plants. One of the plants (PP1) processes small chickens (1,100g live weight) and PP2 processes chickens with 2,800g live weight. In total, 448 samples were collected. Laboratory tests were performed in duplicate for each parameter measured. The results show that moisture levels of fresh giblets were higher in the gizzard, followed by the liver and the heart, whereas in chilled giblets, the gizzard still maintained the highest moisture level, but was followed by the heart and then the liver. Both in fresh and chilled samples, the liver presented the highest protein content, followed by the gizzard and the heart. Water to protein ratios were higher in chilled than in fresh samples, and was highest in the heart, followed by the gizzard and the liver. After immersion in the chiller, the heart presented the highest water absorption rate (6.59%), which was significantly higher compared with those of the liver (4.16%) and the gizzard (4.51%). Considering that the water absorption rates obtained both in fresh and chilled chicken giblets were below 8.00%, the following upper limits of water absorption are suggested for chicken giblet processing in Brazil: 7.0% for the heart, and 5.0% for the gizzard and the liver.

植生の吸水が土壌中の化学種分布に及ぼす影響

Laboratory column experiment and numerical simulation were performed to understand soil water transport by plant water uptake and formation mechanism of salt accumulation. After illuminance level raised, temperature and volumetric water content (VWC) in the column were also raised, then water level of Marriott tank was lowered. The rise of VWC may be related to upward movement of solute with water. The results of adsorbed ion distribution showed variability. It seems results of repeated ions adsorption transported by plant water usage. Observed Sodium distributions were agreed well with the root distribution. The dense part of root had higher water absorption rate. According to the numerical results, cation exchange reaction and plant water uptake by root distribution should be considered in the modeling to understand qualitative distribution of chemical components.

Using polyaspartic acid hydro-gel as water retaining agent and its effect on plants under drought stress.

Polyaspartic acid (PASP) hydrogel is an important and widely applied water-retaining agent, thanks to its special space network structure which contains a carboxyl group attached on the side chain. In this study, the PASP hydrogel with high water absorption rate (300–350 g H2O/g hydrogel) was developed and adopted to transplant Xanthoceras sorbifolia seedlings in the ecological restoration project of Mount Daqing National Nature Reserve. Transplantation experiments showed that the survival rate and leaf water content index for X. sorbifolia seedlings were increased by 8–12% and 4–16%, respectively. Additionally, compared with the counterpart without PASP hydrogel, the value of chlorophyll fluorescence that was considered as one of the most important indicators of plant physiology, was significantly improved with the addition of PASP hydrogel. The PASP hydrogel displays a promising future for the applications of increasing the survival rate and simultaneously alleviating the drought stress effects on the pioneer plants in arid and semi-arid areas.

Potential utilization of date palm wood as composite reinforcement

This research reports the results of an experimental study on the physical, chemical, and mechanical properties as well as the thermal behavior of eight varieties of date palm residues coming from the same environment. The aim is to evaluate each variety of this natural material to be used thereafter, individually or as a mixture, in the manufacturing of composite materials. The results show that Rachis variety exhibits relatively high values of tensile strength and Young’s modulus; they attained 213 MPa and 8.5 GPa, respectively. In contrast, Petiole variety exhibits relatively high values of specific mechanical properties. This is due to its low value of bulk density, which is 0.160 g/cm3. Besides that, Petiole variety is also characterized by relatively high porosity and high rate of water absorption; they reached 81.52 and 140%, respectively. Results of thermal analysis show that Leaflets variety provides the highest resistance to thermal degradation; its main degradation occurred at 360℃.

Análise da hidratação de grãos de alpiste

Neste trabalho se objetivou estudar o fenômeno de hidratação em grãos de alpiste (Phalaris canariensis L.) em diferentes temperaturas. Foram utilizados grãos secos de alpiste, embebidos em água destilada, nas temperaturas de 10, 25 e 45 °C. O aumento da temperatura resultou em aumento da taxa de absorção de água e o modelo de Peleg se ajustou satisfatoriamente aos dados experimentais. O coeficiente efetivo de difusão aumentou com a variação crescente da temperatura, de 2,396 até 2,428×10-13 m2 s-1. A dependência do coeficiente efetivo de difusão com a temperatura pode ser descrita pela relação de Arrhenius apresentando, para a faixa de temperatura estudada, a magnitude da energia de ativação aparente para o processo de 39,239 ± 4,3463.

Correlation between morphology, hydration kinetics and mathematical models on Andean lupin (Lupinus mutabilis Sweet) grains

This work describes the hydration kinetics of Andean lupin (Lupinus mutabilis Sweet) grains, correlating its morphology with mathematical models in order to explain the process. Microstructural analysis of the grains was performed using a scanning electron microscope and the hydration kinetics was determined between 23 °C and 60 °C. The hydration kinetics showed the sigmoidal behavior, which was fitted with two sigmoidal models. Further, this behavior was explained by the grain morphology, demonstrating that the seed coat was the cause of this behavior, related to the slow initial water intake. It was demonstrated that the water entered to the grain by diffusion through the seed coat, and by capillarity through the hilar fissure. Besides, an increase in the process temperature resulted in higher water absorption rate, smaller hydration time and higher final moisture content, enhancing the process. Each model's parameter (equilibrium moisture, water absorption rate and lag phase time) was then modeled as function of the temperature. Finally, two general models were obtained with good agreement, which can be used to predict the moisture of the grain as function of both time and temperature.

Development of Natural Bio-Plantation Waste as Pulp for Paper Making

This project investigated the use of facile pulping methods to produce pulp from mixed bio-plantation waste fibres using sodium hydroxide, ethanol and garbage enzyme. Papers were successfully made from mixture of corn husk fibres with other bio-based green fibres such as banana stems and pineapple leaves. Soda pulping was found to be efficient in converting the cellulosic bio-fibres to the pulps used for paper making. The papers produced have low tensile strength, high water absorption, high bio-decomposition and degradation rate, as compared to commercial papers. SEM observation revealed that paper made from mixed bio-fibres have lightly cross-linked structures compared to heavily cross-linked or compact network structures found in commercial papers. The paper can be used in applications that require high water absorbency. The paper making process is more environmental friendly as it reduces the usage of wood fibres and hence reduces the environmental problem caused by deforestation.

Influence of Treatment Methods on the Strength and Performance Characteristics of Recycled Aggregate Concrete

With the rise in the adoption of recycled aggregate for construction, investigation on ways to improve its quality has been wide spread. The major factor that affects the quality of recycled aggregate is the large amount of cement mortar that remains on the surface of the recycled aggregate. This attached mortar results in higher porosity, higher water absorption rates, and thus a weaker interfacial zone between new cement mortar and aggregates, weakening the strength and mechanical performance of concrete made from recycled aggregate. This paper attempts to compare the effect of chemical as well as mechanical treatment approaches in reducing the mortar attached to aggregate. Six series of concrete mixtures are prepared using natural aggregate, recycled aggregate, recycled aggregate treated with HCl and H2SO4, recycled aggregate obtained after scrubbing treatment, and heating and scrubbing treatment. The physical and mechanical properties of these aggregates, and their strength and performance of recycled aggregate concrete are determined. The results show that treatment with H2SO4, and heating and scrubbing yield, aggregate with reduced water absorption and other desired properties of natural aggregate. The concrete made out of these treated aggregates are able to achieve strength and performance characteristics on par with natural aggregate concrete.

Properties of wood-plastic composites (WPCs) reinforced with extracted and delignified wood flour

Abstract The water sorption and mechanical properties of wood-plastic composites (WPCs) made of extracted and delignified wood flour (WF) has been investigated. WF was prepared by extraction with the solvent systems toluene/ethanol (TE), acetone/water (AW), and hot water (HW), and its delignification was conducted by means of sodium chlorite/acetic acid (AA) solution. A 24 full-factorial experimental design was employed to determine the effects of treatments and treatment combinations. WPCs were prepared with high-density polyethylene (HDPE) and treated WF was prepared by means of extrusion followed by injection molding, and the water absorption characteristics and mechanical properties of the products were evaluated. WPCs produced with extracted WF had lower water absorption rates and better mechanical properties than those made of untreated WF. WPCs containing delignified WF had higher water absorption rates and improved mechanical performance compared with those made of untreated WF.

Influencing factors and mechanism of water absorption process of iron ores during sintering

The appropriate content and distribution of sinter moisture play an important role in the granulation of iron ores. In this study, the effects of porosity, size distribution, and particle shape on the water absorption rate (WAR) of four types of iron ores were analyzed by using the immersion method and capillary water absorption method. In addition, the mechanism underlying the water absorption process in iron ores was unraveled. It is found that the WARs of iron ores decrease quickly with the increase in water absorption time at the initial stages of water absorption. With further increase in absorption time, the WARs decrease gradually, until near 0. Iron ores with higher porosity, smaller particle size, and plate-like structure have the higher WARs. Compared with pores in the single-particle iron ore, voids among particles in the multi-particle iron oxide play an important role at the initial stages of water absorption. The water absorption mechanism of all single-particle and multi-particle iron ores analyzed in this study includes four steps, wherein the first three steps play a significant role in the sintering process.

Fabrication and Characterization of Macroporous Chitosan/PVA Composite Sponges for Wound Dressing

ABSTRACTThe present investigation involves the synthesis of chitosan based composite sponges in view of their applications in wound dressing, antibacterial and haemostatic. A facile CO2 bubbles template freeze-drying method was developed for the fabrication of macroporous chitosan- poly(vinyl alcohol) (PVA) composite sponges with a typical porosity of 50% and pore size of 100-300 µm. The composite sponges show a high water absorption rate up to 60 times of its weight and a water vapor transmission rate of 30 ∼ 70g/m2 • h. Effects of the content of cross-linking agent and PVA on mechanical properties and moisture permeability were examined. Improved strength and flexibility of the chitosan sponges were observed with the presence of PVA. Further, the antibacterial and haemostatic activities have been demonstrated. The Chitosan/PVA sponges of high liquid absorption, appropriate moisture permeability, excellent antimicrobial and haemostatic activities have a great potential for wound dressing applications.

Water absorption in bean seeds (Phaseolus vulgaris L.) DURING PROCESSIN

The purpose of this paper was to estimate and to evaluate the hydration curves of three kinds of dry bean varieties (Phaseolus vulgaris L.), besides adjusting the Peleg’s model to the experimental values under several soaking temperatures. Bean seeds of pinto, black and red kidney varieties were soaked in distilled water in the temperatures of 20, 30, 40 and 50 °C. The constant C1 (Peleg rate constant) significantly decreased with increase in temperature (20 a 50 °C) demonstrating that the initial rate of water absorption increased with temperature. The three bean varieties exhibited a high rate of water absorption in the beginning of the hydration process, being that Peleg’s model adjusted satisfactorily to the experimental data.

Hydration kinetics of direct expanded tef flour breakfast cereals in water and milk

Hydration kinetics of tef flour breakfast cereals extruded at barrel temperatures of 110, 130, and 150°C was investigated by hydrating them in water and whole milk at 25°C (±1°C). The normalized Weibull model described the rehydration characteristics of the extrudates in water and milk adequately (R2 = 0.98–0.99). Water absorption rate was significantly (P < 0.05) influenced by barrel temperature where extrudates processed at 150°C barrel temperature exhibited high water absorption rate followed by those extruded at 130 and 100°C, respectively. Hydration rate and equilibrium moisture content were higher for samples hydrated in water than those in milk. In view of the values of the shape parameter β, the hydration process is predominantly controlled by diffusion (β = 0.40–0.51) for samples extruded at 110°C whereas external resistance to mass transfer dominated (β = 0.60–0.73) those extruded using 150 and 130°C. Extrudates processed at 130 and 150°C exhibited better hydration characteristics. Thus, these temperature ranges could be used to produce extruded products from tef.

Expression analysis and molecular characterization of aquaporins in Rhodnius prolixus

Aquaporins (AQPs) are water channels responsible for transport of water and, in some cases, transport of small solutes such as urea and glycerol across lipid bilayer membranes. Hematophagous insects, such as Rhodnius prolixus, ingest large volumes of fluid and must rapidly eliminate the excess of water and salts from the blood meal within the gut. In order to deal with this increase in body fluid volume, a hormone-controlled diuresis is activated, during which a high rate of water and salt absorption occurs across the anterior midgut, followed by secretion of water and salts by the Malpighian tubules (MTs). Previously, one member of the MIP family (major intrinsic protein that includes the AQP family) was identified in the MTs of R. prolixus, and named RpMIP. We have described here that the RpMIP gene has different variants, and is present in tissues other than MTs. In addition, we have characterized a new AQP (RhoprAQP1) found in different tissues of R. prolixus. The expression of these transcripts in unfed insects as well as blood fed insects was evaluated using real-time quantitative PCR. Molecular models of the predicted proteins were constructed and the characteristics of their pores evaluated. A yeast complementation assay was used to validate that the products of these transcripts were bona fide AQPs. Both RhoprAQP1 and RhoprMIP-A were capable of transporting water whereas RhoprMIP-A was also capable of transporting H2O2. Taken together, these analyses suggest that RhoprMIP is probably an aquaglyceroporin, while RhoprAQP1 appears to be a strict aquaporin that transports only water.

Development of Performance Optimization of Recycled Aggregate

Recycled aggregate concrete (RAC) differ from natural aggregate concrete in mechanical and durability properties. The poorer qualities of recycled aggregate (RA) limit utilization of RAC in engineering. Cement mortar attached on the surface of recycled aggregate result in higher water absorption rate. Also, interfacial zone between recycled aggregate and new mortar consist of loose and porous hydrates. Investigation is devoted to effects of different approaches on improving performance of RA to compensate the lower quality of RA. The pre-soaking treatment approach reduces the old cement mortar and removes the weaker link in interfacial zone. Moreover, The two-stage mixing approach (TSMA) is adopted, leads to the formation of a thin layer of cement slurry on the surface of RA which permeates into the porous old cement mortar, filling up the old cracks and voids for increasing compressive strength. Correlations in methods have been obtained and discussed.

Synthesis and properties of a novel superabsorbent polymer composite from microwave irradiated waste material cultured Auricularia auricula and poly (acrylic acid‐co‐acrylamide)

ABSTRACTA novel superabsorbent polymer composite was successfully synthesized from waste material cultured Auricularia auricula (WMCAA) and poly (acrylic acid‐co‐acrylamide) (P(AA‐co‐AM)) using microwave irradiation. Optimal synthesis conditions were determined by investigating the water absorbency of the superabsorbent composite. The effects associated with weight ratios of WMCAA, acrylamide (AM) monomers, initiators, and acrylic acid (AA) crosslinkers, as well as the degree of neutralization of AA were examined. The maximum water absorbencies were found to be 1548 g/g (distilled water) and 72 g/g (0.9% NaCl solution). Fourier transform infrared spectroscopy (FTIR) was applied to determine the molecular structure of the superabsorbent composite, and scanning electron microscopy (SEM) was used to demonstrate the characteristic compact and porous structure of the material. Further studies conducted via transmission electron microscopy (TEM) revealed the formation of a novel interpenetrating polymer network structure. Thermogravimetry/differential thermal (TG/DTG) analysis demonstrated improved thermal stability in the composite material compared with WMCAA. Additionally, high water absorption rates observed in the polymer during the swelling process indicated first‐order kinetics. The water absorption and adsorption of the superabsorbent composite were studied in a variety of fertilizer solutions, revealing an indirect relationship between water absorbing ability and fertilizer concentration. Conversely, a direct relationship was observed between absorbed fertilizer and fertilizer concentration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3674–3681, 2013

Polymer-Based Hermetic Packaging for Flexible Micro Devices

In recent years, polymers have been widely adopted as a low-cost, light-weight and high-flexibility alternative to traditional silicon materials for MEMS. However, the majority of polymers do not provide hermetic protection because of their high moisture- and gas permeation rates. Yet, hermetic packaging is critical for many applications such as medical devices [1], RF MEMS [2] and micro heat pipes [3]. In particular, our group has been developing flexible thermal ground planes based on heat pipe technology [3] for advanced electronics cooling applications. Heat pipes require hermetic sealing, while flexibility requires the structural material to be polymer-based. Hermetic packaging methods for MEMS typically include welding, soldering [4], and various epoxies and polymers [1, 2, 5] to bond the parts in a package together. The bond interface is a major potential source of gas and moisture leakage. Although welds and solder joints offer effective hermetic seals, the bond interface is mechanically rigid. On the other hand, flexible bond materials like epoxies typically possess high moisture absorption rate and bonding strength degradation at high temperature [6] while polymers such as BCB [2] or LCP [7] either provide only semi-hermetic sealing or degrade at high temperature. We report a polymer-based hermetic packaging approach using fluorinated ethylene propylene (FEP), which possesses flexibility, high operating temperature compatibility (204°C), chemical resistance, and low water absorption rate. We report results of hermeticity tests in which FEP, solder, and epoxy were used to bond a copper-clad kapton “lid” onto a water-containing copper vessel which is then kept in an oven at 100 °C. The only path for water loss is through the bond interface. We show that the FEP-bonded test vehicles result in negligible water loss comparable to the solder-bonded containers, and far outperforming the epoxy-bonded containers.

Effect of Ceramsite Type on the Internal Relative Humidity of Ceramsite Concrete

The internal relative humidities of concrete using different types of ceramsites with different prewetting degrees were monitored by humidity sensors. The study reveals that the internal relative humidity of concrete using low water absorption rate ceramsites declines more slowly than that of concrete using high water absorption rate ceramsites when not prewetting; the internal relative humidity of concrete using high water absorption rate ceramsites is higher than that of concrete using low water absorption rate ceramsites when their prewetting degrees (1h or 24h) are the same; the internal relative humidity of concrete using ceramsites is higher than that of ordinary concrete, whether the ceramsites are prewetted or not.