Showing papers on "Distilled water published in 2004"

Dissolution of pulp tissue by aqueous solution of chlorhexidine digluconate and chlorhexidine digluconate gel.

Abstract: Aim To evaluate the activity of various root canal irrigants on bovine pulp tissue. Methodology The irrigants tested were: 0.5, 1.0 and 2.5% sodium hypochlorite; 2% aqueous solution of chlorhexidine digluconate; 2% chlorhexidine digluconate gel (Natrosol™); and distilled water as control. Bovine pulp fragments were weighed and placed in contact with 20 mL of each tested substance in a centrifuge at 150 r.p.m. until total dissolution. Dissolution speed was calculated by dividing pulp weight by dissolution time. Statistical analysis was performed using the Kruskal–Wallis test. Results Distilled water and both solutions of chlorhexidine did not dissolve the pulp tissue within 6 h. Mean dissolution speeds for 0.5, 1.0 and 2.5% sodium hypochlorite solutions were 0.31, 0.43 and 0.55 mg min−1, respectively. The solvent ability of chlorhexidine solutions was similar to that of distilled water. The results for sodium hypochlorite solutions, chlorhexidine solutions and distilled water were statistically different (P > 0.01). Conclusions Both chlorhexidine preparations and distilled water were not able to dissolve pulp tissue. All sodium hypochlorite solutions were efficient in dissolving pulp tissue; the dissolution speed varied with the concentration of the solution.

Removal of methyl orange dye and Na2SO4 salt from synthetic waste water using reverse osmosis

Abstract: The efficiency of reverse osmosis (RO) membranes used for treatment of colored water effluents can be affected by the presence of both salt and dyes. Concentration polarization of each of the dye and the salt and the possibility of a dynamic membrane formed by the concentrated dye can affect the performance of the RO membrane. The objective of the current work was to study the effect of varying the Na 2 SO 4 salt and methyl orange (MO) dye concentrations on the performance of a spiral wound polyamide membrane. The work also involved the development of a theoretical model based on the solution diffusion (SD) mass transport theory that takes into consideration a pressure dependent dynamic membrane resistance as well as both salt and dye concentration polarizations. Control tests were performed using distilled water, dye/water and salt/water feeds to determine the parameters for the model. The experimental results showed that increasing the dye concentration from 500 to 1000 ppm resulted in a decrease in the salt rejection at all of the operating pressures and for both feed salt concentrations of 5000 and 10,000 ppm. Increasing the salt concentration from 5000 to 10,000 ppm resulted in a slight decrease in the percent dye removal. The model’s results agreed well with these general trends.

Photodegradation of rhodamine B in water assisted by titania films prepared through a novel procedure

Abstract: Well-crystallized anatase thin films were prepared through direct oxidation of metallic titanium with 30 mass% hydrogen peroxide solution at 80 ◦ C for 5 h, followed by soaking in distilled water at 80 ◦ C for 3 days The photodegradation of a dye solution, rhodamine B (RB), assisted by such deposited anatase films was studied It was found that the well-crystallized anatase thin films induced complete degradation of RB in water with an initial concentration of less than 002 mM after 4–5 h of illumination under a 450 W high-pressure mercury lamp The RB decayed directly to colorless end products of water and mineral acids However, when the photocatalytic activity of the anatase films decreased after several repeated uses, an N-de-ethylation process producing rhodamine as an intermediate was evident during the photocatalytic degradation of RB © 2004 Elsevier BV All rights reserved

Effect of hybridization and chemical modification on the water‐absorption behavior of banana fiber–reinforced polyester composites

Abstract: The water sorption characteristics of banana fiber–reinforced polyester composites were studied by immersion in distilled water at 28, 50, 70, and 90°C. The effect of hybridization with glass fiber and the chemical modification of the fiber on the water absorption properties of the prepared composites were also evaluated. In the case of hybrid composites, water uptake decreased with increase of glass fiber content. In the case of chemically modified fiber composites, water uptake was found to be dependent on the chemical treatment done on the fiber surface. Weight change profiles of the composites at higher temperature indicated that the diffusion is close to Fickian. The water absorption showed a multistage mechanism in all cases at lower temperatures. Chemical modification was found to affect the water uptake of the composite. Among the treated composites the lowest water uptake was observed for composites treated with silane A1100. Finally, parameters like diffusion, sorption, and permeability coefficients were determined. It was observed that equilibrium water uptake is dependent on the nature of the composite and temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3856–3865, 2004

Effects of storage media on mechanical properties of adhesive systems.

Abstract: PURPOSE To evaluate the effects of water vs oil storage on the mechanical properties of dental adhesives over 3 and 6 months METHODS Adhesive resin sheets were prepared by pouring either Single Bond (SB), One-Step (OS) or Clearfil Liner Bond 2V (CL) into a mold measuring 15 x 15 x 08 mm After solvent evaporation, the adhesives were light-cured, removed from the mold and trimmed to either hourglass or I-beam shapes that were used to determine the true stress (TS) and modulus of elasticity (E), respectively Control adhesive specimens were subjected to tensile testing at 06 mm/minute after 24 hours of immersion in distilled water Experimental specimens were stored at 37 degrees C in either distilled water or mineral oil and tested after 3 and 6 months The data were analyzed by two-way ANOVA and Tukey's test RESULTS Storage in water significantly decreased the TS and E of SB and OS specimens after 3 and 6 months (P 005) Storage in oil significantly increased the TS of the three adhesives after 3 and 6 months (P > 005), and the same trend was observed for E value of CL sample (P > 005) CLINICAL SIGNIFICANCE Exposure of cured adhesive systems to long-term immersion in water caused marked reduction in their mechanical properties Reduced mechanical properties of the adhesive system may compromise resin/dentin bonds and have a clinical implication on the longevity of adhesive restorations

Synthesis and properties of Novel sulfonated polyimides from 2,2'-bis(4-aminophenoxy)biphenyl-5,5'-disulfonic acid

Abstract: Novel sulfonated polyimides (SPIs) were prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), 2,2′-bis(4-aminophenoxy)biphenyl-5,5′-disulfonic acid (oBAPBDS) with nonlinear configuration, and common nonsulfonated diamines. Water uptake (WU) in liquid and vapor, water stability, and proton conductivity σ of the resulting SPI membranes were investigated. They were soluble in m-cresol and dimethylsulfoxide, and their WUs in liquid were much larger than those of the SPIs from other sulfonated diamines with linear configuration such as 4,4′-bis(4-aminophenoxy)biphenyl-3,3′-disulfonic acid (BAPBDS). NTDA-oBAPBDS membrane was soluble in water at room temperature, whereas all the oBAPBDS-based copolyimide membranes were insoluble in water and maintained mechanical strength after being soaked in distilled water at 80 °C for 40–1000 h. This much improved water stability was due to the enhanced solubility stability of membrane toward water. The water vapor sorption isotherms were rather similar between the SPIs with the nonlinear and linear configurations of sulfonated diamine moieties. The present SPIs with IECs of 1.8–2.6 meq/g, including NTDA-BAPBDS, showed reasonably high proton conductivities under the highly humid conditions and roughly fell on the same σ–WU relation line. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1432–1440, 2004

Experimental analysis of coupled water and chloride transport in cement mortar

Abstract: Coupled water and chloride transport in cement mortar is analyzed experimentally in the paper. Samples with initial moisture content corresponding to 45% relative humidity are subjected to one-sided sodium chloride-in-water solution uptake, and moisture profiles and chloride concentration profiles are determined in three chosen time intervals. In the evaluation of measured moisture profiles and chloride concentration profiles, diffusion model is employed. Moisture diffusivity is determined as function of moisture content and chloride diffusion coefficient as function of chloride concentration using two methods commonly used for analysis of moisture profiles, namely the double integration method and the Matano method. The highest values of both coefficients are obtained by Matano method for the curves corresponding to 24 h exposure to the solution, the lowest values by Matano method for 168 h, the results obtained by double integration method are in between. The complementary experiments with distilled water as penetrating liquid performed for the sake of comparison do not show this feature. It is observed that water transport in the initial time period is for the chloride solution faster and in later times slower than for distilled water. Therefore, the observed differences in the calculated apparent values of moisture diffusivity and chloride concentration coefficients are attributed to the fact that Cl− and Na+ ions are adsorbed on the pore walls faster than water molecules. This effect should be included into the mathematical models using ion binding isotherms.

Effect of traditional and alternative intracoronal bleaching agents on microhardness of human dentine.

Abstract: summary The purpose of this study was to compare the effect of traditional and alternative bleaching agents on microhardness of human dentine when used intracoronally. Thirty-six premolars were divided into six groups and bleaching agents were sealed into the pulp chambers as follows: group 1 – distilled water (control), group 2–30% hydrogen peroxide solution, group 3 – sodium perborate mixed with distilled water, group 4 – sodium perborate mixed with 30% hydrogen peroxide solution, group 5–35% carbamide peroxide gel, group 6–35% hydrogen peroxide gel. Access cavities were sealed and the teeth were stored in distilled water at 37°C. After 7 days, each tooth was sectioned at the cemento-enamel junction level and microhardness testing was carried out on dentine. The results showed that treatment with 35% hydrogen peroxide gel, 30% hydrogen peroxide solution and 35% carbamide peroxide gel reduced the microhardness of outer dentine to a small extent while treatment with sodium perborate mixed with water and sodium perborate mixed with 30% hydrogen peroxide solution did not significantly alter the microhardness of dentine.

Leaching and mechanical properties characterization of dental composites.

Abstract: The objective of this study was to determine the leaching of Ba, Si, and Sr from four dental composites: Restolux (RX), Micronew (M), Renew (RW), and Choice (C) and to correlate the effects of such leaching with flexure strength and modulus of elasticity. The specimens were 3 x 3 x 25-mm bars, polished with 120- and 240-grit SiC paper, and were aged for 4, 6, and 8 months in artificial saliva, distilled water, and a 50/50 mixture of ethanol and distilled water. Inductively coupled plasma with mass spectroscopy (ICP/MS) was used to determine the ion concentrations after aging. The greatest release of Ba and Sr occurred after aging in 50/50 volume fraction mixture of ethanol/water and for Si in artificial saliva. The 50/50 solution caused a breakdown of the resin and glass matrix, resulting in an increase of Ba and Sr, whereas aging in artificial saliva resulted in an ion charge balance, which allowed an elevated and continuous release of Si. The flexure strength and the elastic modulus showed a gradual decrease over time, with the greatest decreases occurring following aging in the 50/50 water/ethanol solution, but little correlation with the leaching of the filler ions.

Determination of Optimal Water Solubility of Capsaicin for Its Usage as a Non-toxic Antifoulant

Abstract: Capsaicin, a non-toxic natural product antifoulant, is an attractive alternative to the currently used toxic metal-based antifoulants for protecting the submerged surfaces. The problem associated with conducting capsaicin experiments is its limited aqueous solubility. A procedure was developed to obtain the maximum capsaicin concentration in water. Capsaicin was first dissolved in one of the three organic solvents, methanol, ethanol, and acetone. The organic solvent was replaced by gradually adding distilled water and evaporating the organic solvent. The best solvent for obtaining highest concentration of capsaicin in water was ethanol. A maximum capsaicin in water 6400 ppm was achieved by using 16 mg capsaicin dissolved in 0.8 ml ethanol followed with the addition of 2.5 ml distilled water in 0.2 ml increments and then slow evaporation of the solvent. The concentration obtained using our approach is well above the threshold concentration of capsaicin in deterring the marine organism attachments.

Characterization of whey protein emulsion films

Abstract: Stearic acid was incorporated into whey protein through emulsification to produce films. Whey protein films were prepared by dispersing 6.5% protein in distilled water. Glycerol was the plasticizer agent. Stearic acid was added at different levels (0.0 to 1.0%) and the films were analyzed at different pHs (5.0, 6.0, 7.0 and 9.0). The emulsion films were evaluated for mechanical properties, water vapor permeability and protein solubility. It was observed that water vapor permeability and protein solubility values for the film decreased with increasing fatty acid content in the film, but the mechanical properties also decreased.

Degradation of AlN Powder in Aqueous Environments

Abstract: The reactivity of AlN powder in an aqueous environment was studied by measuring the pH and the temperature during the hydrolysis of the powder at room and elevated temperatures. The influences of the powder concentration and the starting pH of the slurry were also investigated. The results of the measurements at room temperature show that there is an incubation time before the start of the AlN hydrolysis reactions. Once this incubation time is over, the pH and the temperature of the slurry start to increase, indicating the onset of the reactions. A higher starting temperature not only speeds up the reaction of the AlN powder with water, but it also shortens the incubation time. In addition, the starting temperature influences the morphology of the reaction product: at temperatures below 60 °C, the final product of the hydrolysis is crystalline Al(OH)3, whereas at higher temperatures (above 60 °C), crystalline AlOOH is formed. At very low pH values (pH = 1), the reaction of AlN powder with water is prevented (i.e., the incubation time is very long), whereas in an alkaline environment, the incubation time is approximately the same as in distilled water, but the reaction is accelerated.

The effect of washing on physicochemical changes in packaged, sliced green peppers

Abstract: Summary Whole green bell peppers (Capsicum annuum L.) were obtained through a local fresh-cut company. They were washed in a 100 ppm chlorine solution, dried and then sliced into 0.5-cm wide strips. A bulk sample of slices was divided into four treatments: (1) no wash, (2) one wash in fresh distilled water, (3) two sequential washes in fresh distilled water, and (4) three sequential washes in fresh distilled water. Retention of firmness of the pepper slices during storage at 7 °C improved with the number of washes after cutting. The modification of package atmosphere was less in all wash treatments than in the ‘no wash’ control. The sliced tissues of ‘no wash’ controls had higher levels of acetaldehyde and ethyl acetate. Analysis of the wash water revealed that sequential washes with water removed incremental amounts of acetaldehyde and soluble phenols from the cut surfaces of the tissue. These results show that washing has a dramatic effect on physicochemical measures of quality in green pepper slices, and it is likely that this effect is mediated by the removal of stress-related compounds produced during the cutting operation. While acetaldehyde and total phenolics were the two stress-related compounds measured in the wash water, it may be that other compounds removed in the wash water could have contributed to the beneficial effects on quality reported in this study.

Influence of extraction parameters on the mutagenicity of soil samples

Abstract: The aim of this study was to investigate the influence of four extraction parameters (type of solvent, temperature, duration of extraction, and soil mass/solvent volume ratio) on the mutagenicity of soil extracts. Four urban soil samples were submitted to the micro-method adaptation of the Ames test on Salmonella typhimurium according to the following sequence: identification of the most sensitive strain (TA98 or TA100), the best solvent(s), the optimum extraction temperature and extraction time, and finally the optimal soil/solvent ratio. Extraction was thus performed using eight different solvents (distilled water, dichloromethane, acetonitrile, acetone, cyclohexane, methanol, hexane, or ethanol), two temperatures (room temperature or 37 °C), two durations (4 or 24 h), and two soil mass/solvent volume ratios (1:2 or 1:10). The results show that strain TA98 was more sensitive than strain TA100, and the observed mutagenicity was expressed as number of TA98 revertants per mg of soil equivalent. No mutagenicity was induced by the distilled water extracts, whereas most of the organic solvent extracts induced a significant mutagenic response. A dichloromethane/acetone mixture appeared to be the best compromise for extraction of mutagens from the urban soils tested. Moreover, the present study showed that a higher mutagenic activity was generally obtained with a temperature of 37 °C (compared to room temperature), with an extraction time of 24 h (compared to 4 h), and with a soil mass/solvent volume ratio of 1:10 (compared to 1:2).

A new photoproduct of the drug furosemide in aqueous media

Abstract: The solar phototransformation of furosemide has been investigated in aqueous media. Irradiation of the drug in distilled water, in water and humic acids or nitrate ions, and in sewage sludge water affords a new dehalogenated dimer. The formation of the dimer has been explained by the formation of a cation radical intermediate. The low-measured environmental concentration of furosemide with respect to predicted environmental concentration in the Po and Lambro Rivers could be justified by its phototransformation.

Influence of chromizing treatment on the corrosion behavior of AISI 316 stainless steel in supercritical water oxidation

Abstract: SCWO, sometimes referred to as hydrothermal waste processing, uses the solvating traits of water in its supercritical condition to effectively destroy liquid organic wastes. One major problem in the supercritical water oxidation process is corrosion, because all metallic tubes in the process are exposed to high temperature and high pressure as well as severe corrosive species such as Cl−, F−, S2−, and O2−. The presence of Cl− when the pH of a solution is very low and the solution has excess oxygen causes active corrosion and metal loss by metal-chloride and/or oxychloride formation. This study performed a chromizing treatment on 316 stainless steel and immersion tests in supercritical water. Weight change of chromized steels and untreated steels was measured, and the chemical state and composition of oxide films on 316 stainless steel were investigated. On the basis of SCWO tests using distilled water, the oxide layer was found to be very thin and homogeneous and weight gain was observed regardless of testing temperature, while the chromizing treatment slightly reduced weight gain. In the case of SCWO tests using salt water, weight loss was observed regardless of testing temperature and its corrosion mode was pitting by chloride ion, while chromizing treatment greatly decreased the corrosion rate.

Water and electrolyte absorption from hypotonic oral rehydration solution in rat small intestine and colon.

Abstract: Background: The authors evaluated and compared the efficacy of hypotonic oral rehydration solutions (ORS), isotonic ion solutions, and distilled water to elucidate the relation between net water absorption and osmolality, or between electrolyte absorption and their ion concentrations in rat small intestine and colon. Methods: Water and electrolyte absorption from two hypotonic ORS (Solita-T granules No. 2 [STG2]; sodium 60 mEq/L, osmolality 249 mOsm/L, Solita-T granules No. 3 [STG3]; sodium 35 mEq/L, osmolality 199 mOsm/L), two isotonic ion solutions (Aqualight [AL]; sodium 30 mEq/L, osmolality 290 mOsm/L, Pocarisweat [PS]; sodium 21 mEq/L, osmolality 300 mOsm/L), and distilled water, were evaluated by an in vivo perfusion technique with the small intestine and colon of anesthetized rats. Results: In the small intestine and colon, two hypotonic ORS significantly promoted net water absorption much greater than did two isotonic ion solutions (P < 0.05). Net sodium absorption from two hypotonic ORS was significantly greater than that from two isotonic ion solutions (P < 0.05). Sodium absorption from all solutions was greater in the colon than in the small intestine. Distilled water did not contribute to give net water absorption in the small intestine, but in the colon, it caused almost equivalent net water absorption to that by two hypotonic ORS. The largest amount of sodium secretion from the small intestine and colon was induced by distilled water. Conclusions: These data indicate that low osmolality is a crucial factor to facilitate water absorption, and the electrolytes, sodium and chloride, can effectively be salvaged in the colon.

Boiling and Bacillus spores.

Abstract: To the Editor: Public health authorities rely upon "boil water" advisories to alert consumers if a potable water supply is deemed unsuitable for consumption. Holding water at a rolling boil for 1 minute will inactivate waterborne pathogens, including encysted protozoa (1–3). Spores of Bacillus anthracis, the agent that causes anthrax, are one of the microorganisms most refractory to inactivation by the boiling water method. This study was conducted to determine the resistance of spores of B. anthracis Sterne and three other strains of Bacillus spp. in boiling water. B. anthracis Sterne (Colorado Serum Co., Denver, CO) was grown on soil extract peptone beef extract medium (4). Spores were harvested from the agar plates and washed four times by centrifugation with sterile distilled water, treated with 50% (vol/vol) ethanol while being shaken at 100 rpm for 2 h, then washed an additional four times by centrifugation with sterile distilled water. Spores of one of the B. cereus strains were obtained from a commercial source (Raven Biological Laboratories, Omaha, NE). Spores were produced in broth cultures for the other Bacillus spp. The second B. cereus (ATCC 9592) was grown in a generic sporulation medium (5), and B. thuringiensis var. israelensis (ATCC 35646) was grown in Schaefer's medium (6). Spores were purified by gradient separation using RenoCal-76 (Bracco Diagnostics, Princeton, NJ) (6). Spore preparations were stored in 40% (vol/vol) ethanol at 5°C until used. Duplicate experiments for each species were conducted in 1-L glass beakers containing 500 mL of municipal drinking water (21±2°C, pH 8.2±0.5, free available chlorine 0.5±0.3 mg/L). The beakers were left uncovered or covered with a watch glass. Steam was allowed to escape from the covered beakers through the mouth of the pouring spout. Water samples were injected with the spore preparations, heated to boiling on a hot plate, and held at boiling temperature for various times. Measuring the boiling times began when the sample reached a rolling boil. A thermocouple thermometer (Cole-Parmer, Vernon Hills, IL) directly above the liquid-air interface determined the air temperature above the boiling water after 5 min of exposure. At the conclusion of the various boiling times, the samples were removed from the heat source and allowed to cool at room temperature before analysis. These samples contained <0.2 mg/L of free available chlorine. Decimal dilutions of the water samples were analyzed in triplicate by the membrane filter procedure with nutrient agar (7). Spores of all strains of the Bacillus spp. analyzed in this study were inactivated after boiling for 3–5 min in a covered vessel (Table). Spores still survived after 5 min of boiling in an open vessel for all of the Bacillus spp. Temperatures immediately above the surface of the boiling water in the covered vessels averaged 98.9°C, while the temperature immediately above the water level in the uncovered vessels averaged 77.3°C. Table Inactivation of Bacillus spp. by boiling in tap water In a comprehensive literature review citing published reports dating back to 1882, Murray (8) noted that boiling times reported to destroy B. anthracis spores varied over a range of 1 to 12 min. In his own study of 17 strains of B. anthracis, Murray (8) found that boiling times of 5 to 10 min were required to achieve inactivation. Stein and Rogers (9) reported that vigorous boiling for 3 to 5 min destroyed spores from 43 strains of B. anthracis. In our study, boiling water in a covered vessel for 3 to 5 min destroyed spores of the Bacillus spp. by greater than four orders of magnitude. Boiling for 5 min in an uncovered vessel was not as effective as boiling in a covered vessel and allowed all Bacillus spp. spores to survive. On the basis of the initial levels of spores used in this study, holding water at a rolling boil for 1–3 min in an open container would not inactivate the spores. Boiling time refers to the total time the water is held at a rolling boil and should not be confused with the first sign of bubbles from dissolved gases in the water. Since water boils at lower temperatures at higher altitudes (approximately 90°C at 3 km), boiling times must also compensate for decreased atmospheric pressure conditions (1,2).

Influence of chemical and mechanical polishing on water sorption and solubility of denture base acrylic resins

Abstract: Influence of polishing methods on water sorption and solubility of denture base acrylic resins was studied. Eighty samples were divided into groups: Classico (CL), and QC 20 (QC) - hot water bath cured; Acron MC (AC), and Onda Cryl (ON) - microwave cured; and submitted to mechanical polishing (MP) - pumice slurry, chalk powder, soft brush and felt cone in a bench vise; or chemical polishing (CP) - heated monomer fluid in a chemical polisher. The first desiccation process was followed by storage in distilled water at 37 +/- 1 degrees C for 1 h, 1 day, 1, 2, 3 and 4 weeks. Concluding each period, water sorption was measured. After the fourth week, a second desiccation process was done to calculate solubility. Data were submitted to analysis of variance, followed by Tukey test (p

On the modulation effect of pulsing and static magnetic fields and mechanical vibrations on barley seed hydration.

Abstract: The changes of wet and dry weights of barley seed in different periods of swelling were studied in seeds treated with Extremely Low Frequency Electromagnetic Fields (ELF EMF), Static Magnetic Fields (SMF) and Mechanical Vibrations (MV) in cold (4 degrees C) and warm (20 degrees C) distilled water as well as in seeds non-treated (control). The metabolic dependent seed hydration, dry weight loss and water binding in seed were modulated by preliminary EMF, SMF and MV-induced treatment of distilled water. The specific electrical conductivity (SEC) of control and treated distilled water was measured before the seed incubation. Frequency and intensity "windows" (i.e. range of frequency or intensity) for the effect of EMF, MV and SMF (correspondingly) on seed hydration, solubility and water binding in seed were studied. These "windows" were different in various phases of seed swelling. It is suggested that water structure modification is the result of valence angle changes (SMF and EMF) and dipole molecules vibration (EMF and MV) has different effects on the process of hydration, solubility and water binding in seed. These results are important from the point of understanding the mechanisms of the biological effect of EMF, as well as from the point of agriculture.

Organic-inorganic composite water retaining agent with fertilizer slow release function and its preparing method

Abstract: The present invention is composite organic-inorganic water retaining agent with fertilizing slowly releasing function and its preparation process The fertilizing slowly releasing water retaining agent is prepared with cheap attapulgite, humic acid capable of increasing organic matter in soil, acrylic acid and acrylamide as main material and through adding initiator and cross-linking agent, grafting copolymerization and cross-linking in water solution, washing, drying, and crushing The water retaining agent has distilled water absorbing capacity of 400-600g/g and cost 30-40 % lower than that of available organic polymer water retaining agent With water absorbing, water retaining and fertilizer slow releasing functions, the present invention may be used in water-saving agriculture, ecological restoring engineering and other fields

Effects of inorganic ions on leachability of wood preserving N'N-hydroxynapthalimide (NHA).

Abstract: Southern yellow pine sapwood stakes and blocks were treated with the sodium salt of the calcium-precipitating compound N'N-hydroxynapthalimide (NHA) and leach tested for 2 weeks using the American Wood-Preservers' Association (AWPA) standard. Leacheates were measured for NHA using a microplate optical density ultraviolet reader, and leach rates were estimated for tap water, distilled water, and seawater. The percentage of NHA lost from blocks ranged from a low of 5.0 percent for seawater to 26.4 percent for distilled water. Clearly, higher inorganic ion concentrations in the leaching solutions resulted in less chemical leaching of NHA. To further reduce NHA leachability, additional groups of NHA-treated blocks were post-fixed with 2 percent CaCl 2 . With CaCl 2 post-fixation prior to leaching, the percentage of leached NHA was reduced to 4.3 percent for seawater and 12.7 percent for distilled water. Additional stakes were pressure-treated with aqueous NHA concentrations ranging from 0.1 to 2.0 percent and then leached in distilled water. The percentage of release of NHA in 2 percent treated stakes was 9.1 percent in distilled water; in 0.1 percent treated stakes, 31.5 percent NHA was released. We conclude that NHA leach rates can be decreased by precipitation with inorganic ions (such as calcium) and increased concentration levels of NHA during pressure treatment.

Natural vacuum distillation technique-Part II: Experimental investigation

Abstract: This part of the study is concerned with the experimental investigation and uncertainty analysis of natural vacuum distillation process. Natural vacuum distillation (NVD) system is operated in the forms of free and forced mass convection. The experiments are conducted at temperatures of 20 and 40°C of network water as fluid in the system. During the experiments, total pressure losses are measured as 15.33kPa during free mass convection distillation while 14 kPa during forced mass convection distillation. Depending on time and temperature, the ratios of vapour/wastewater (v/ww)free, distilled water/wastewater (dw/ww)forced and total energy/distilled water (te/dw) are experimentally determined. Moreover, the ratios of mass and energy balances are experimentally obtained. Accordingly, it is found that the ratios of (dw)forced/(dw)free vary between 1.4 and 1.6 depending on the wastewater temperatures. In addition, 2.5 kWh kg−1 distilled water is experimentally used in the NVD system with free mass convection while 2.6 kWh kg−1 distilled water in the NVD system with forced mass convection. In case of reduction of heat and pressure losses in the systems, 0.7 kWh is needed for the former while 1.3 kWh of energy is required for the latter. Copyright © 2004 John Wiley & Sons, Ltd.