Higher Water Absorption Rate Research Articles

Preliminary Research on Waste Incineration Bottom Ash Concrete

We use the bottom ash from Harbin Municipal Solid Waste Incineration Plant as concrete coarse aggregate and study the engineering properties of the coarse aggregate, failure mode of waste incineration bottom ash concrete, the relationship between compressive strength and bottom ash coarse aggregate replacement rate, water cement ratio, apparent density and development trend of compressive strength. Comparing with natural aggregates, the bottom ash has higher water absorption rate, lower apparent density and crushing value index. The failure mode of waste incineration bottom ash concrete is similar to ordinary concrete and the flat and elongated particles have effect on compressive strength. Bottom ash coarse aggregate replacement rate has different effects on compressive strength in different water cement ratio. Compressive strength of waste incineration bottom ash concrete has the same development trend with ordinary concrete. Compressive strength and apparent density has a linear relation.

Experimental Study on Basic Behavior of Recycled Fine Aggregate Mortar

In order to study the mechanical behavior of recycled fine aggregate mortar, 11 kinds of different recycled fine aggregate replacement rate (ranged from 0% to 100%, level differential 10%) of cement mortar test specimens are designed. The failure pattern and the mechanical performance indexes of the cement mortar under different recycled fine aggregate replacement rate are gained by test. And the different physical indexes of natural fine aggregate and recycled fine aggregate are measured in detail. The experiment findings indicate that because the water absorption rate of the mortar with high porosity is higher, and there are mass microcracks in recycled fine aggregate interior due to damage accumulation, the lower apparent density, the higher water absorption rate and the quicker water absorption speed of recycled fine aggregate are caused. So the fluidity of recycled fine aggregate mortar is fine, but the water retention is bad, the compressive strength is lower than the natural fine aggregate mortar about 50%. But the replacement rate has little effect on the mortar strength.

Influence of the isolation procedure on the characteristics of fiber-rich products obtained from quince wastes

The upgrading potential of quince ( Cydonia oblonga Miller) wastes was evaluated for production of fiber-rich powders with useful functional and physiological properties. As a first approach, three products were obtained by applying different drying conditions without or with a previous extraction either with water or ethanol. Chemical compositions as well as physical and functional properties of the isolated fractions were evaluated in relation to water or oil absorption for characterization. The products obtained presented interesting hydration properties comparable to those reported for citrus and apple pulps. At the same time, all dried fractions showed high spontaneous water absorption rate in the kinetics assay. Oil absorption seemed to essentially depend on the microstructural characteristics of the fiber powders, whereas parameters involving water absorption were really determined by the material’s hydrophilicity. Specific volume, which was also in part a direct function of structural differences, was associated to the ability for oil uptake.

Frontal polymerization synthesis and characterization of Konjac glucomannan‐graft‐acrylic acid polymers

AbstractKonjac glucomannan‐graft‐acrylic acid polymers, used as superabsorbent polymers (SAPs), were synthesized by frontal polymerization (FP). The features of front propagation including front velocity and maximum temperature (Tmax) were influenced by the amount of glucomannan, initiator, and environment temperature. The graft copolymer was characterized by FTIR, DSC, and SEM. The amount of crosslinking agent mainly determined the crosslinking degree of SAPs that would affect the water absorbency and microstructure. Water absorbency of SAP was also investigated and most of them displayed high water absorption rate. The aforementioned results allow us to conclude that FP can be considered as a promising method to fabricate SAP for its excellent advantages. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3391–3398, 2009

Water retention properties of porous geopolymers for use in cooling applications

A series of geopolymers were prepared with varying ratios of sodium silicate, metakaolinite, NaOH and H 2O and their porous properties, water retention and mechanical properties were determined, to develop materials for counteracting heat island effects. Samples were prepared with the molar ratios SiO 2:Al 2O 3:Na 2O:H 2O of 3.66:1: x: y, where x = 0.92–1.08 and y = 14.2–19.5. The porous and mechanical properties of the geopolymers showed a good correlation with the H 2O/Al 2O 3 ratio ( y); an increase in y produced an increase in the pore volume (from 0.26 to 0.46 ml/g), the pore size (from 15 to 390 nm) and the water absorption (from 27.2 to 51.1%). The same increase in y decreased the bulk density (from 1.29 to 0.99 g/cm 3), the bending strength (from 14.2 to <5 MPa) and the water retention. Thus, the H 2O/Al 2O 3 ratio is the most important factor for controlling the porous properties of these materials, since geopolymers with higher H 2O/Al 2O 3 ratios are more porous and have higher water absorption rates, making them suitable as materials for surface cooling by water evaporation. Geopolymers with lower H 2O/Al 2O 3 ratios are more suitable for water retention applications, and have the advantage of higher mechanical strength.

EFFECT OF BARREL TEMPERATURE ON REHYDRATION KINETICS OF DIRECT‐EXPANDED TEF FLOUR BREAKFAST CEREAL

ABSTRACT The effect of barrel temperature (110, 130 and 150C) on the rehydration kinetics of tef flour extrudates was investigated. Rehydration was conducted in distilled water for 300–420 min using a constant‐temperature water bath at 25C (±1C). Water absorption rate was high at the early stages (60–90 min) of hydration, decreased subsequently and finally approached an equilibrium. Three models, namely, Peleg's equation, first‐order kinetic and normalized Weibull model, were fitted to the rehydration data. The three models described the rehydration characteristics adequately (R2 = 0.95–0.99). The water absorption rate and equilibrium moisture content were found to be barrel temperature‐dependent (P &lt; 0.05). Extrudates processed at a barrel temperature of 150C exhibited a high water absorption rate, followed by those extruded at 130 and 110C, respectively. The equilibrium moisture content of extrudates processed at 150 and 130C was significantly (P &lt; 0.05) higher than those extruded at 110C. In view of the values of the shape parameter βof the normalized Weibull model, the mechanism of water absorption appeared to be by diffusion for extrudates processed at 130C (β = 0.67), whereas in extrudates processed at 110 (β = 0.89) and 150C (β = 1.03), external resistance to mass transfer and relaxation phenomena, respectively, were found to be the water absorption mechanisms. In comparison, the normalized Weibull model described the rehydration characteristics relatively better, resulting in smaller RMSE value.PRACTICAL APPLICATIONSSome extruded food products, like breakfast cereals, are consumed after being rehydrated (e.g., in milk). The rehydration characteristics, in turn, are influenced by the extrusion operating conditions. Fast rehydration without much change in the crispiness is a required attribute of breakfast cereals. Describing and modeling the kinetics of moisture uptake as a function of the operating conditions could lead to a better understanding and control over the mechanisms underlying the sorption process and the ability of the product to rehydrate. Such information is vital in process and quality optimization.

Experimental definition of microclimatic conditions based on water transfer and porous media properties for the conservation of prehistoric constructions: Cueva Pintada at Galdar, Gran Canaria, Spain

Microclimatic parameters and natural materials were studied in order to assess conservation of the cave complex at Galdar, Gran Canaria. Based on the microclimatic data, experimental simulations were carried out to quantify water retention capacity and water vapour transport kinetics under continuously changing extreme temperatures and relative humidity values. The behaviour of natural construction materials is greatly influenced by changes in thermo-hygrometric conditions and is linked to pore structure. The host rock has a complex porous media: high porosity and polymodal pore size distribution, where the smallest pores contribute to water condensation, whilst large pores lead to high water absorption rates. The axial compressive strength of the host-rock decreases between 30 and 70% at water saturation. Stuccos covering cave wall paintings are formed by clay minerals, mainly smectites. These clay minerals cover a large specific surface area, which leads to a high capacity for water condensation and retention. It is also shown that neither water condensation nor vapour transport are noticeably modified by the presence of stucco on the host-rock when rapid, highly variable changes occur in environmental conditions if large shrinkage cracks are present. Results show that safe threshold microclimatic conditions can be found below 75% RH in the natural temperature range and that slight variations in temperature and relative humidity do not modify durability properties.

Preparation and Physical Properties of Hollow Polyester Filaments with High Breathability, Water Absorption and Release Rates

This paper reports the preparation of hollow polyester filaments with high water absorption and release rates, and the study of their physical properties using differential scanning calorimetry, thermogravimetric analysis, density gradient, gel permeation chromatography, rheometry and statistical regression analysis. Four readily soluble poly(ethylene glycol)-modified cationic dyeable poly(ethylene terephthalate) (PEG-CDPET) polymers were prepared, with 3 mol % of the sodium salt of dimethyl 5-sulfo-isophthalate (SIPM). The poly(ethylene glycol) (PEG) contents were 3 and 6 wt% and the number-average molecular weights ([Formula: see text]) of the PEG were 600 and 8000 (g/mol). Blends of regular PET and PEG-CDPET were spun into hollow filaments. These hollow filaments were then drawn and treated with aqueous sodium hydroxide. The crystallinity of the PEG-CDPET polymers declined as the PEG content increased, given a fixed SIPM content. Furthermore, the crystallinity of the PEG-CDPET polymers declined as the [Formula: see text] of the PEG increased for the same SIPM and PEG contents. The SIPM and PEG segments did not change the original PET unit cell. The sodium sulphonate (–SO3Na) functional groups and the PEG molecules were only on the crystal surface and in the amorphous regions. Obviously, the rate constants for alkaline hydrolysis were in the order: PEG-CDPET polymer&lt;&lt;CDPET polymer&lt;regular PET polymer. The water-absorption and release and the heat retention properties of alkali treated PET/PEG-CDPET polyblend hollow filaments were better than those of the regular PET filaments. The porous nature of the large filaments (from 0.02-1 μm in diameter) was observed after alkali treatment of the PET/PEG-CDPET polyblend hollow filaments. Additionally, the hollowness of the PET/PEG-CDPET polyblend filaments was observed to increase from 40 to 42% after alkali treatment.

Pad Soaking Effect on Interfacial Fluid Pressure Measurements During CMP

Prior work has shown that there exist a sub-ambient fluid pressure at the interface between a rigid flat and the polishing pad during chemical mechanical polishing (CMP). This sub-ambient fluid pressure can have a significant impact on the polishing process since its magnitude may be similar to the applied load, depending on conditions. Further results have shown that there is a relationship between pad soaking time and the magnitude of this sub-ambient fluid pressure. This paper addresses measurements of the pad soaking time versus the magnitude of the sub-ambient interfacial fluid pressure. Experiments utilized a Rodel IC1000 polishing pad made of foamed polyurethane with average void size of 30 to 50 microns. Pad soaking tests indicated that the weight of the pad increased with soaking time due to water absorption. There is a high rate of water absorption initially before the pad becomes saturated and the mass of the pad stabilizes. It is also observed that the pad material is impermeable to water and most of the water penetrated only the topmost layer of voids in the material. These experiments suggest that the water progressively “softens” the top layers of the pad during the soaking and causes the sub-ambient fluid pressure to increase in magnitude. A model of the sub-ambient fluid pressure increasing as the elastic modulus of the pad decreases is also suggested.

Growth Responses of Drought Resistant Rice Cultivars to Soil Compaction under Irrigated and Succeeding Non-irrigated Conditions during the Vegetative Stage

We investigated whether drought resistant rice cultivars exhibit higher dry-matter production under wet and dry compacted soil conditions in the vegetative stage and determined the dominant factors governing resistance to soil compaction. Three rice cultivars, a drought-sensitive Nipponbare, and drought-resistant Senshou and Dular, were grown in pots at four soil bulk densities (SBD) ranging from 1300 to 1600 dry soil kg m−3. Root and shoot dry matter productions was slightly smaller in Nipponbare over the 29 days after sowing under irrigated conditions than in the other cultivars at all SBDs. Senshou and Dular also maintained a higher dry matter production, both in relative and absolute values, than Nipponbare under the condition of withheld irrigation from days 29 — 39 after sowing. The higher stomatal conductance and leaf water potential of these two cultivars were supported by a larger root system which was mostly accompanied by lower top-root ratios in the irrigated and compacted soils. The higher plant growth rate under the non-irrigated condition might have been a result of both the higher water absorption rate and water use efficiency, which in turn were supported by the larger root biomass. We conclude that the ability of rice to rapidly develop a root system in the early vegetative phase under compacted soils facilitates plant production under subsequent soil desiccated conditions.

Novolac epoxy resins and positron annihilation

AbstractFour kinds of epoxy resins: cresol novolac, tris‐hydroxyphenylmethane, tetramethylbiphenol, and bisphenol A, were cured with phenol novolac epoxy resins. Characteristics of these epoxy compounds were studied by the positron annihilation lifetime (PAL) technique. Glass transition temperatures, thermal expansion coefficients, and volume of intermolecularspace holes among polymer chains were obtained from the lifetime, τ3, of the long‐lived component of ortho‐positronium. It was revealed that, at the glass transition temperature, Tg, the volume of the hole created among polymer chains expanded 1.4 times the volume at room temperature. The smaller flexural modulus of tris‐hydroxyphenylmethane than that of the other samples was explained by the volume of intermolecular‐space holes obtained from τ3. Aging effects were seen in the data of the intensities, I3, of ortho‐positronium, which became smaller after heating the samples above Tg. I3 and τ3 were strongly affected by the density of cross‐linkings, and their chemical structures. The larger the density of cross‐linkings, the smaller I3 and higher Tg were obtained. Epoxy compounds with the higher water‐absorption rates had larger intermolecular‐space holes. © 1993 John Wiley &amp; Sons, Inc.

Temperature changes using excimer laser irradiation in a cochlear model

The excimer laser-ArF has certain characteristics that render it ideal for the perform- ance of stapedotomy. These include the short wavelength of the emitted laser beam (193 nm), its high water absorption rate, the ability of pin-point focusing and its capability of operating in a pulse mode. In an effort to measure the temperature changes of the labyrinthine fluids in the inner ear during excimer laser irradiation, a cochlear model with the dimensions of the normal vestibule was de- signed. In this model cerebrospinal fluid (CSF) was used as a substitute for the labyrinthine fluids. Our study showed that the number of pulses needed to create the stapedotomy fenestra to the bony plate were 112-132. The temperature elevation of the CSF during laser irradiation showed only a slight increase of 0.1-0.4~ The results of this study are very encouraging for the future use of the excimer laser in clinical situations.

Cuticular Properties and Postharvest Calcium Applications Influence Cracking of Sweet Cherries

Abstract The influence of stomata, the stylar scar, cuticular fractures, and Ca2+ on susceptibility of ‘Bing’ sweet cherry fruit (Prunus avium L.) to water injury was studied. Water injury was first detected as an increase in cell turgor. Water penetration caused separation of the cuticle from the epidermal cell wall. Swelling in the epidermal cell wall region resulted in cuticular fracturing that generally preceded fruit cracking. Uncracked fruit that had cuticular fractures softened rapidly. Stomata were sparsely distributed on the fruit surface and were often fixed in an open or partially open position. Water injury was not visible at stomata even when injury occurred adjacent to the stomatal region. Initial signs of injury were commonly visible near the stylar scar. Histochemical studies revealed that the surface of the stylar scar was devoid of a cuticle covering and was rich in insoluble carbohydrates. Greater penetration of solute containing 45Ca2+ occurred at the stylar scar. Fine fractures in the cuticle surface were observed in fruit at harvest time in 1985 and 1986. Cherry fruit with cuticular fractures had a higher water absorption rate than unfractured fruit. In immersion tests, Ca2+ reduced cherry cracking. EGTA increased fruit cracking; this increase was negated by adding Ca2+. Neither Ca2+ nor EGTA affected the water absorption rate of the fruit. EGTA decreased the cracking threshold of the fruit, while Ca2+ increased it. Soluble pectin content of the immersion solution rose with increasing incubation times. EGTA increased while Ca2+ markedly decreased soluble pectin concentration in the immersion solution. Histochemical studies indicated a breakdown of the cell wall structure in the epidermal region of water-injured fruit. Autoradiographs of fruit immersed in a solution containing 45Ca2+ showed the epidermal region to be the site of Ca2+ action in altering fruit cracking. Chemical name used: Ethyleneglycol-bis-(β-aminoethyl ether) N,N,N,N-tetraacetic acid (EGTA)

Studies on corresponded-relations between plant characters and cultivation methods. III. Comparison of water balance in plants at transplanting among millets.

Some experiments on transpiration and water absorption were conducted to determine the different rooting ability of millets at the time of transplanting from the viewpoint of water balance in the plant. This report also contains work on the effect of seedling quality on rooting. These experiments were done during the period from 1978 to 1981. The results obtained were as follows: 1. Transpiration rate per leaf arca was the highest in Japanese barnyard millet and the lowest in sorghum under the condition of water culture. Among the seedlings from the nursery bed filled with volcanic soil, however, Italian millet showed the highest transpiration, and the low values were seen in common millet and Japanese barnyard millet (Table 1). 2. The reason why Italian millet was subject to losing water balance in the plant at transplanting time, compared with finger millet were as follows: (1) Water content of the plant organs was lower in Italian millet and its transpiration rate was higher. This might be due to the higher stomata density per leaf area. (2) Top/Root ratio of Italian millet is extremely high and it becomes still higher by unavoidable cutting of roots at the time of transplanting. This results in a considerable decrease in water absorption by roots, although Italian millet has high water absorption rate and high level of bleeding water per root dry matter weight. This decrease in water absorption compared to a higher transpiration rate of leaves may result in losing water balance in Italian millet. On the other hand, finger millet had lower water absorption and also lower bleeding water level per root dry matter weight. But this crop had a high water content in its plant organs and a lower ratio of Top/Root. Therefore, the water balance can be kept in the plant. In the case of sorghum, ablility of water absorption and bleeding was low and the water balance in the plant may be kept with lower water contents because of its lower transpiration rate due to fewer stomata per leaf area. Japanese barnyard millet and common millet showed a similar tendency to finger millet and Italian millet, respectively (Table 2 and 3, Figs. 4-5). 3. To understand the effect of seedling quality on taking root, the rooting ability of seedlings grown at different fertilizer levels was investigated. New roots were more numerous in the seedlings of the standard fertilizer plot than the non-fertilizer application plot. The longest root was found in the seedling of the non-fertilizer plot. In the high fertilizer plot, only finger millet could produce more roots. Two weeks after transplanting, plants from the standard level plot showed greater growth, whereas common millet, Japanese barnyard millet and Italian millet displayed less growth at a higher level of fertilizer than the standard level (Table 4 and 5). From the above results, the higher Top/Root ratio is likely to cause taking root to fail at transplanting mainly due to damage of roots by pulling seedlings from the nursery bed, and the resultant decrease of water absorption by roots and loss of water balance in the plant can be seen. Therefore, especially the direct sowing type plants such as Italian millet and common millet are not suitable for transplanting. As to the effect of seeding quality on taking root, the seedings grown at the standard fertilizer levels generally showed good growth with many newly-emerged roots. But with a higher fertilizer level, all the millets except finger millet could not attain desirable growth.

Dietary water balance in a tropical insect

Dietary water intake of the tropical grasshopperPoecilocerus pictus fedad libitum from hatching to death on the milkweedCalotropis gigantea averaged 85 or 51 g at 26°C and 171 or 78 g at 36°C for a female and male respectively. As much as 54 or 96 g dietary water is lost via faeces by a female at 26 or 36°C; the corresponding values for a male was 37.5 and 36.2 g. A male or female carried at death about 9 or 6% of the respective dietary water absorbed at 26 or 36.°C. Water loss via exuvia amounted to 26 mg in all the series. Due to oviposition 4.8 or 7.4% of the total water absorbed was lost by a female at 26 or 36°C. There exist a very close relationship between the efficiencies of matter assimilation and water absorption. The high dietary water intake and absorption rates reported for the tropical lepidopteranDanaus chrysippus are correlated with the accumulation of water to meet the requirements during the nonfeeding pupal stage.

Active transport of chloride in eel intestine with special reference to sea water adaptation

1. 1. The electrical potential difference (PD) and short-circuit current ( I sc) across the intestine were near-zero in fresh water eels, and the active transport of Na + and Cl − was almost identical. 2. 2. When eels were adapted to sea water, PD and ( I sc) increased markedly in serosa-negativity against mucosa due to the development of active Cl − transport. 3. 3. The intestinal PD and I sc were serosa-positive in fresh water teleosts, while they were serosa-negative or near-zero in marine species. In rainbow trout, reversal of the PD was observed when they were transferred from fresh water to sea water. 4. 4. The electrical resistance of the intestine decreased during sea water adaptation of the eel and rainbow trout. 5. 5. The results are discussed in relation to a high rate of intestinal water absorption of teleosts in sea water.

INTUMESCENCES ON POPLAR LEAVES. II. PHYSIOLOGICAL CONSIDERATIONS

In preceding papers (12, 13) the writer has described the occurrence and structure of intumescences on leaves of Populus grandidentata, Populus tremuloides, Eucalyptus coccifera, Eucalyptus cornuta, Hieracium venosum, Mitchella repens, and Thurberia thespesioides. In the present paper an account is given of an attempt to determine the factors involved in stimulating the cells to the unusual growth, which result in these abnormal protuberances. The hypotheses which have been developed to account for the induction of intumescences have been almost as numerous as the records of their occurrence. Sorauer (i8) believed that metabolic disturbance due to an excessive water supply and low assimilation accounted for the outgrowths. In a later paper (I9) he added another factor to the complex, namely, the effect of a high temperature. An excessive water supply due to low transpiration and a high rate of water absorption by the roots, was advanced by Atkinson (I, 2) as the stimulus to formation of oedemas on the tomato and the apple, though he considered that low illumination was favorable also, since it led to the development of weak, watery tissue. Steiner (20) discovered intumescences on leaves of Ruellia formosa and Aphelandra Porteana which he believed were caused by high humidity. By subjecting leaves of Aphelondra to a saturated atmosphere he was able to induce these outgrowths, but he failed to secure them by treating the leaves with copper sulfate, ammonium chlorid, formic acid and various other chemicals; by keeping them in the dark; or by submerging them in water. Douglas (5) induced intumescences on leaves and stems of potato plants by covering them with bell jars. Since the intumescences occurred in either strong or weak light, but not in total darkness, she concluded that light as well as humidity played a part in the abnormal stimulation of the plants. She found also that the abnormalities could be produced by treating young potato plants with copper compounds, as Von Schrenk (23) had previously found in the case of cauliflower. Ktister (i I) secured intumescences on leaves of Populus floated on water in the presence or the absence of light. In strong light, however, the