Showing papers on "Distilled water published in 2009"

Preparation and Properties of Novel Slow-Release NPK Agrochemical Formulations Based on Poly(acrylic acid) Hydrogels and Liquid Fertilizers

Abstract: New slow-release agrochemical formulations based on cross-linked poly(acrylic acid) hydrogels and liquid fertilizers (LF) were prepared by free radical copolymerization of acrylic acid (AA) and N,N′-methylenebisacrylamide directly in the LF solution. Two NPK liquid fertilizer compositions containing urea and potassium and ammonium phosphates were employed. For comparison, AA was also polymerized under identical conditions in distilled water. The resulting products were characterized by FTIR spectroscopy and scanning electron microscopy, and their water absorption and slow-release properties were determined. The results showed that the swelling degree (SD) of the hydrogels synthesized depended on the overall concentration of reactants (monomers and initiator), LF composition and cross-linking agent, and initiator concentrations. By appropriately combining these reaction parameters, superabsorbent hydrogels with SDs in distilled water ranging from a few hundred to 1000 g of water/g of xerogel can be obtaine...

Studies on Water Absorption of Bamboo-Polyester Composites: Effect of Silane Treatment of Mercerized Bamboo

Abstract: The effect of silane treatments on the water absorption properties of mercerized bamboo matting reinforced polyester composites were investigated. Treatments using γ-Aminopropyltriethoxy silane, 3-trimethoxysilylpropyl methacrylate, Vinyltris(2-methoxyethoxy)silane, Bis[3-(triethoxysilyl)propyl] tetrasulfide, 3-aminopropyltrimethoxy silane and n-Octyltrimethoxy silane were carried out to improve the water resistant property of the bamboo fibers. Water absorption in the composites was studied by long-term immersion and 2 h boiling in distilled water. The process of absorption of water was found to follow the kinetics and mechanism described by Fick's theory. Alkali treatment results in reduction of water absorption from 51% to 35%. Further reduction is observed with silane treatment. Water absorption varies between 19% and 44%, the minimum being for aminopropyl triethoxy silane-treated composites.

Release of bisphenol A from polycarbonate baby bottles: water hardness as the most relevant factor

Abstract: The concentrations of bisphenol A (BPA) in the content of polycarbonate baby bottles reported by scientific literature were almost always clearly below 1 μg/l, but in a German consumer journal they reached 157 μg/l. These high values were interpreted as a result of microwave heating, but here they are shown to be the result of testing with tap water. Since BPA is primarily released by degradation of the polycarbonate, rather than by migration from the polymer, testing with food simulants (distilled water or distilled water/ethanol) is not appropriate. Degassing of tap water during boiling causes the pH to increase and the water to become more aggressive. BPA concentrations may reach 50 μg/l if a polycarbonate bottle is sterilized by boiling water in it (well feasible only by means of microwave heating) and this same water is used to prepare a beverage. Increased concentrations are also observed when boiling-hot beverages with a high pH are filled into the bottle, such as boiled plain water or tea. Respecting simple rules, the BPA concentrations can be kept below 0.5 μg/l.

Synthesis, swelling behaviors, and slow-release characteristics of a guar gum-g-poly(sodium acrylate)/sodium humate superabsorbent

Abstract: Superabsorbents used in agricultural and ecological projects with low-cost, slow-release fertilizers and environmentally friendly characteristics have been extensively studied. The use of a natural polymer as the matrix and then further polymerization with some func- tional material has become the preferred method. In this work, with natural guar gum (GG), partially neutralized acrylic acid, and sodium humate (SH) as the raw materi- als, ammonium persulfate as the initiator, and N,N 0 -meth- ylenebisacrylamide (MBA) as the crosslinker, GG-g- poly(sodium acrylate) (PNaA)/SH superabsorbents were synthesized through a solution polymerization reaction and were characterized with Fourier transform infrared spectroscopy, scanning electron microscopy, and thermog- ravimetric analysis. The effects of the SH content and MBA concentration on the water absorbency were investi- gated. The results showed that the introduction of SH into the GG-g-PNaA system could improve the water absorb- ency, swelling rate, pH-resistant property, and reswelling capability, and the superabsorbent containing 15 wt % SH had the highest water absorbency of 532 g/g of sample in distilled water and 62 g/g of sample in a 0.9 wt % NaCl solution. The slow release in water and water retention in sandy soil tests revealed that the superabsorbent could act as a fertilizer as well as an effective water-saving material for agricultural applications. V C 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2102-2111, 2009

Characterization and Pool Boiling Heat Transfer Studies of Nanofluids

Abstract: Copper nanoparticles with an average size of 10 nm are prepared by the sputtering method and are characterized using different techniques, viz., X-ray diffraction spectrum, atomic force microscopy, and transmission electron microscopy. The pool boiling heat transfer characteristics of 0.25%, 0.5%, and 1.0% by weight concentrations of copper nanoparticles dispersed in distilled water and in distilled water with 9.0 wt % of sodium dodecyl sulfate (SDS) are studied. Also the data for the boiling of pure distilled water and water with SDS are acquired. The above data are obtained using commercial seamless stainless steel tube heater with an outer diameter of 9.0 mm and an average surface roughness of 1.09 μm. The experimental results concluded that (i) critical heat flux (CHF) obtained in water with surfactant nanofluids gives nearly one-third of the CHF obtained by copper-water nanofluids, (ii) pool boiling heat transfer coefficient decreases with the increase in the concentration of nanoparticles in water base fluids, and (iii) heat transfer coefficient increases with the addition of 9.0% surfactant in water. Further addition of nanoparticles in this mixture reduces the heat transfer coefficient. (iv) CHF increases nearly 50% with an increase in concentration of nanoparticles in the water as base fluid and nearly 60% in the water with surfactant as base fluid.

Steam generation process for enhanced oil recovery

Abstract: The system and method for steam production for extraction of heavy bitumen includes a method of mixing fuel and oxidizing gases, combusting the mixture, mixing combustion gas with water containing solids and organics, separating solids, using heat from the separated gas to produce distilled water, recycling the distillation facility brine with the combustion gas and removing solids thereof, generating steam from the distilled water and injecting the steam through an injection well or using it above ground for oil recovery. The system includes a combustion boiler, a direct contact steam generator, a gas-solids separator, and a heat exchanger with a water treatment facility like a distillation facility. The water feed of the present invention can be water separated from produced oil and/or low quality water salvaged from industrial plants, such as refineries and tailings as make-up water.

Development and Evaluation of an Ozonated Water System for Antimicrobial Treatment of Durum Wheat

Abstract: Ozonated water is reported to be effective in reducing the microbial load in foods such as fruits, vegetables, and grains. Ozonated water may be an effective alternative to chlorinated water in treating durum wheat before milling. Therefore, durum wheat was washed with ozonated water and analyzed for yeast and mold count (YMC) and aerobic plate count (APC). A system for producing and monitoring ozonated water was developed. The effect of water quality (tap, distilled, and ultra-pure), temperature (7, 15, and 25 degrees C), and pH (2, 4, and 6.5) was evaluated on the following: steady-state dissolved ozone concentration, ozone decay constant, half-life, mass transfer coefficient, equilibrium ozone concentration, and solubility ratio. The study of these parameters was important to attain a stable, high dissolved ozone concentration at the outset of washing and to have information for system improvement and scale-up. A 1% acetic acid solution (pH 2) at 15 degrees C resulted in high dissolved ozone concentration (21.8 mg/L) and long half-life (9.2 min). Subsequently, wheat was washed with 5 wash water types: distilled water, ozonated water (16.5 mg/L), chlorinated water (700 mg/L), acetic acid solution (1%), and acetic acid + ozonated water (1%, 20.5 mg/L). The treated samples were analyzed for YMC and APC. The acetic acid + ozonated water treatment was the most effective, with a reduction of 4.1 and 3.2 log(10) colony forming units/g in YMC and APC, respectively. Though ozonated water was not very effective alone, it was useful in combination with acetic acid.

Zeolite Synthesised from Fused Coal Fly Ash at Low Temperature Using Seawater for Crystallization

Abstract: A sample of coal fly ash from an Italian thermoelectric power plant was used in order to synthesize zeolite by hydrothermal activation after a pre-treatment fusion with NaOH. The experiments involved were performed at different temperatures of crystallization, ranging from 35 up to 60uC, with seawater and distilled water, separately, during hydrothermal process. A comparison between the results obtained from the use of the different kinds of water showed that at low temperature (35–40 uC) the synthesis yield of zeolite X is higher using seawater as crystallizing agent than using distilled water. This implies a possible application for seawater in the solution to the problem of high water volume involved in the zeolite synthesis on a pilot plant

In vitro remineralization efficacy of NaF systems containing unique forms of calcium.

Abstract: Purpose To determine the in vitro remineralization potential of a new calcium phosphate technology in a 1000 ppm F system. Methods 3 mm diameter bovine enamel specimens were mounted, ground and polished, and softened in a carbopol-lactic acid solution (pH = 5.0) for 36 hours at 37 degrees C. Specimens were then measured for baseline Vickers microhardness and stratified (N = 10, mean VHN = 35) into the following groups: Group A: distilled water (negative control); Group B: MI Paste Plus (900 ppm F); Group C: Theramed SOS (1450 ppm F); Group D: "control" dentifrice (1000 ppm F); and, Group E: "test" dentifrice (1000 ppm F) admixed with a new functionalized calcium phosphate system. The groups were then cycled for 10 days in a pH cycling model consisting of four 2-minute treatment periods (diluted 1:3 with distilled water) and one 4-hour acid challenge (carbopol-lactic acid, pH = 5.0) per day. Between these events, specimens were immersed in artificial saliva (pH = 7.0). After 10 days of cycling, the specimens were measured for Vickers surface microhardness and were subsequently microdrilled, with the powder measured for fluoride content using a calibrated fluoride-sensitive electrode. Results Significant differences resulted between the distilled water and fluoride-containing groups. Among the fluoride-containing groups, Group B demonstrated statistically low levels of enamel fluoride deposition and deltaVHN, while Group E statistically outperformed Group D. Among the groups with different calcium systems (Groups B, C, and E), Groups C and E were found to be statistically equivalent and superior to Group B with respect to both bioavailable fluoride and deltaVHN. Based on our results, these data demonstrated the combination of a new calcium phosphate technology plus 1000 ppm F, produced significantly greater remineralization relative to both the 1000 ppm F test dentifrice and MI Paste Plus, and was statistically equivalent to Theramed SOS.

Adaptive fuzzy model identification to predict the heat transfer coefficient in pool boiling of distilled water

Abstract: In this paper, a modeling technique based on fuzzy system is used to predict the heat transfer coefficient in pool boiling of distilled water. To achieve this, an experimental investigation has been carried out for saturated boiling of distilled water from plain copper heating tube surface at atmospheric and sub-atmospheric pressures. An empirical correlation has been established to predict the boiling heat transfer coefficient. Further, the experimental data has been compared with those determined from the zero-order adaptive fuzzy model with heat flux as input variable. The representation accuracies of the pool boiling heat transfer coefficient for fuzzy model is very high as indicated from the performance index. The prediction performance of zero-order adaptive fuzzy model has also been compared with MATLAB based ANFIS function. Further, the statistical attributes are determined and compared with the experimental data set of pool boiling of distilled water available in open literatures.

Water sorption and solubility of different calcium hydroxide cements

Abstract: OBJECTIVES: Calcium hydroxide cements have been largely used in deep cavities due to their abilities to stimulate dentin formation. However, their resistance can be relatively low and their solubility relatively high, in many instances. This study evaluated water sorption and solubility of different calcium hydroxide cements, in order to show alterations that may reduce their effectiveness. MATERIAL AND METHODS: Five discs (20 mm in diameter and 1.5 mm thick) of three different materials (Biocal®, Dycal® and Hidro C®) were prepared with the aid of a ring-shaped metallic matrix. After being stored at 37oC for 24 h, the discs were weighed on a precision weight scale, dehydrated and weighed again. Immediately after weighing, discs were stored for a week in 50 mL of distilled water at 37oC and, then, weighed again, dehydrated and submitted to a new weighing. The loss of soluble material and its water sorption was obtained from the difference between the initial and the final dry mass of each disc, after 1 week of immersion in water. Data were analyzed for significant differences by two-way ANOVA and Tukey's test (p<0.05). RESULTS: Mean water sorption values (g) ± standard deviation and percentage (%), for each evaluated cement, were: Biocal® (0.006 ± 0.001 / 2.15); Dycal® (0.016 ± 0.004 / 5.49); and Hidro C® (0.025 ± 0.003 / 8.27). Mean solubility values (g) ± standard deviation and percentage (%), for each evaluated cement, were: Biocal® (0.002 ± 0.001 / 0.72); Dycal® (0.013 ± 0.004 / 4.21); and Hidro C® (0.023 ± 0.004 / 7.65). CONCLUSIONS: Biocal® absorbed less water and was less soluble than the other evaluated cements; Hidro C® exhibited the highest water sorption and solubility values; and there were significant differences among all evaluated experimental groups.

Use of Calix[4]-bis-2,3-naphthocrown-6 for Separation of Cesium from Pressurized Heavy Water Reactor Simulated High Level Waste Solutions (PHWR-SHLW)

Abstract: Distribution studies on Cs(I) were carried out from pressurized heavy water reactor (PHWR) simulated high level waste (SHLW) solution using calix[4]-bis-2,3-naphtho-crown-6 as the ligand. A mixture of 1:1 nitrobenzene and toluene was evaluated as a suitable diluent. The distribution ratio of Cs(I) increased with the aqueous feed acidity upto 3 M HNO3 and decreased thereafter due to extraction of hydronium ions. The maximum DCs value at ∼3 M HNO3 suggested the possible application of the system for the recovery of radio-cesium from high level waste solution. The addition of 0.4% (v/v) Alamine 336 (a tertiary amine) facilitated the quantitative stripping of Cs(I) with distilled water. Quantitative extraction of Cs(I) from SHLW containing 0.32 g/L of Cs was observed in five contacts at O/A = 1/2 with 2.5 × 10−3 M calix[4]-bis-2,3-naphtho-crown-6. Similarly, quantitative stripping of Cs(I) from the loaded organic phase was achieved in two contacts with distilled water at a volume ratio (O/A) of 2. Se...

Method of preparing bacteria cellulose composite material

Abstract: The invention discloses a method for preparing bacterial cellulose composite material, comprising steps as follows: the production medium of bacterial cellulose is prepared and then acetobacter xylinum strain is put in the production medium of bacterial cellulose; sodium alginate, collagen, water-soluble chitin, gelatin or hyaluronic acid polymer material are added into the production medium in step b for cultivating a bacterial cellulose composite membrane, wherein, the adding amount of the polymer material is 1% to 5% of the weight of the production medium of bacterial cellulose; later the bacterial cellulose composite membrane which is prepared from step c is processed and washed by distilled water till being in a neutral state, and then tiled on filter paper and dried for becoming a finished product. The invention directly adds the polymer material to the production medium of bacterial cellulose; in the process of growth, the bacterial cellulose is directly composited with the added polymer material; the preparation process is simple; and the structure of the composite material of bacterial cellulose is uniform.