Distilled Water Absorption Research Articles

Improving the mechanical performance of adhesively bonded CFRP composite joints exposed to harsh mediums with the reinforcement of boron nanostructures

In this study, the degradation in the strength of adhesively bonded carbon fibre composite joints exposed to different harsh mediums was improved with the addition of silane-modified BN and B4C nanostructures. For this purpose, modified BN and B4C nanostructures were added to the structural adhesive, and then composite plates were bonded with the new reinforced adhesives to produce single lap joints. The produced joints were aged 480, 960, and 1440 h in distilled water, saltwater, sulphuric acid, and ultraviolet light mediums. The mechanical properties of the joints were determined by the tensile test after aging. Moreover, liquid absorption and SEM analyses were performed to observe the structural change in the adhesives. The results revealed that adding nanostructures into the epoxy matrix positively decreases the absorption of distilled water, saltwater, and sulphuric acid solutions. It was also observed that the failure loads of joints decreased depending on the severity of the damage caused by the aging mediums. The joints bonded with BN and B4C nanostructures reinforced adhesives decreased the damage experienced by limiting the harmful effects of the mediums. After 1440 h of aging in the distilled water medium, the composite joints reinforced with BN and B4C nanostructures carried approximately 40% and 37.6% higher loads, respectively, compared to the neat joint. Similarly, as a result of the aging in the UV medium, BN and B4C reinforced joints carried approximately 48.3% and 40.9% higher loads, respectively, while these ratios were determined as 39.7% and 36.7%, respectively, for the saltwater medium.

ВПЛИВ ЕЛЕКТРОМАГНІТНОГО ВИПРОМІНЮВАННЯ МІЛІМЕТРОВОГО ДІАПАЗОНУ НА ОПТИЧНІ ВЛАСТИВОСТІ ВОДИ В РОЗЧИНАХ ГЕМОГЛОБІНУ

The features of the influence of microwave radiation on the optical properties of pure water and water in solutions of hemoglobin in the near infrared range with the aim to characterize the certain structural and dynamic state of water are investigated. The object of the study was the optical properties of distilled water and aqueous solutions of human hemoglobin in the concentration range of 7 and 15 μm and in the temperature range 10–40°C. The optical spectra were recorded by using a BiospecMini spectrophotometer in the wavelength range of 190–1100 nm. In order to increase the accuracy of the analysis of spectral data the spectra were normalized relative to the baseline which was taken as a line that ran parallel to the horizontal axis due to the minimum value of the optical density in the absorption spectrum. The values of the absorption maxima and the optical density were used as the main parameters of the absorption spectra. The B spline function was used to more accurately determine these parameters. Microwave exposures of distilled water and hemoglobin solutions was performed at a wavelength of 7.1 mm with a maximum 100% output power which was calculated to be approximately 24 mW. The dependence of the parameters of the water absorption spectrum in the range of the second overtone of the OH-valence oscillation of the water molecule on temperature is detailed. There were not found statistically significant changes in the distilled water absorption spectrum in the range of the second overtone OH-valence oscillation of the water molecule after one-hour exposure of the microwave EMR. In hemoglobin solutions in this spectral range there is a small but statistically significant increase in absorption. This may indicate on additional EM-induced activation of the libration motions of water molecules and an increase the probability of deformation oscillations that which are manifested in the near IR range in the band of the second overtone of water.

Development of tri-component antibacterial hybrid fibres for potential use in wound care.

Tri-component antibacterial psyllium-alginate-chitosan fibres were developed and their properties were studied with reference to their application in health-care. Psyllium was co-extruded with sodium alginate as a carrier into a coagulation bath containing calcium chloride and hydrolysed chitosan. Different concentrations of the hydrolysed chitosan were used and an in vitro assessment of antibacterial activity of the produced fibres was carried out against the known pathogens of Staphylococcus aureus and Escherichia coli. The effect of hydrolysed chitosan bath composition on physical and mechanical properties of produced fibres was also examined. Chitosan-containing fibres demonstrated a 70-130% thicker dry diameter than the control fibre (F1). The linear density of the fibre increased from 6.8 to 10 tex as the chitosan concentration increased from 10g/l to 30g/l (fibre type F1 to F4). With the addition of hydrolysed chitosan, distilled water absorption was increased while the saline and solution-A (0.83% w/v NaCl and 0.03% w/v CaCl2) absorption decreased. The percentage strain of hybrid fibres was lower than the control fibre due to the inclusion of hydrolysed chitosan. At lower viscosities of the hydrolysed chitosan bath, the fibres were much stiffer due to better penetration of the hydrolysed chitosan. Similarly, at lower viscosities, the tenacities of the hybrid fibres were higher than the control fibre. The hydrolysed chitosan-treated fibres were more effective against Staphylococcus aureus than the Escherichia coli, and the antibacterial activity increased with the decrease in viscosity of the hydrolysed chitosan bath. We developed novel PAC fibres. Antibacterial testing showed that hydrolysed chitosan was more effective against Gram-positive bacteria than Gram-negative bacteria.

Flexural Strength of Single Polymer Polyester Composites as a Measure of Material Degradation

The study compares flexural strength of single polymer polyester composites. Composites under examination had the form of laminates differing in the content of the reinforcement phase and the type of material subject to simulated absorption of distilled water and sea water. Simulation tests of distilled water and sea water absorption for single polymer polyester composites with 5% to 20% reinforcing phase were made in accordance with the PN-EN ISO 62:2008 standard. The determination of the measure of degradation of the composites, the magnitude of the bending stress, was conducted in accordance with the PN-EN ISO:178 standard. This work is part of a research relating to the quality and recycling of single polymer composite materials. The testing part of the research is aimed to define the properties of examined materials before they are used commercially in specific products.

UV-curable epoxy varnishes modified with polyvinyl resins

Abstract Epoxy varnishes based on 3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexanecarboxylate (EEC) and polyvinyl components, i.e., two polyvinyl butyral resins (PVB) and one polyvinyl butyral- stat -acetal resin (PVBA) were prepared and cured using a commercial cationic iodonium photoinitiator and medium-pressure mercury lamp. An influence of a type and content of polyvinyl resin (5, 10, and 20 wt.%) on thermal, optical, mechanical, and barrier features of varnish coatings was investigated. Coats containing the highest amount of PVB resins exhibited higher epoxy group conversion, higher gloss, and smoother surface in comparison with EEC/PVBA samples. Moreover, cured coats and films with PVB reached markedly higher barrier features, i.e., limited distilled water absorption and low water vapor transmission rate. An influence of reactivity and UV transmittance value of the photocurable varnishes on coat wrinkling process was presented and discussed.

The Effect of CNT‐modified matrix of cyanate ester CFRPs on the hydrothermal behavior of the material. Evaluation of the water uptake using electrical resistance measurements

In this work, reference and nanomodified unidirectional cyanate matrix, carbon fiber‐reinforced polymers (CFRPs), were exposed to distilled water at 80°C. Water uptake was investigated as a function of the carbon nanotube CNT wt% content up to saturation level. In parallel the variation of glass transition temperature (Tg) was also monitored using dynamic mechanical analysis tests. The distilled water absorption process was modeled following the Fick's law, and the experimental results were found to be in very good agreement with the theoretical predictions up to saturation. Finally, during the tests and, at defined time intervals the variation of the electrical conductivity of the materials under investigation was studied and a correlation between the water absorption and the variation of the electrical conductivity was established. It was shown that the presence of CNTs into the cyanate matrix affects the water absorption mechanism, since an important amount of additional interfaces has been introduced. POLYM. COMPOS. 37:1072–1077, 2016. © 2014 Society of Plastics Engineers

The Relationship between the Water Absorption Capacity of SAP and the Amount of Entrained Water in HPC

Using SAP is considered as an effective method to counteract autogenous shrinkage of HPC, but the research on the relationship between the water absorption capacity of SAP and the amount of entrained water in HPC is still unclear. In this paper, 6 SAPs with different water absorption capacity were made to discuss the workability and mechanical property of HPC with SAP when different amount of water were entrained. The results showed that the bigger distilled water absorption capacity of SAP is, the smaller the fluidity of cement paste mixed with SAP is, SAP used in HPC should own bigger synthetic pore fluid absorption capacity and smaller distilled water absorption capacity. When 0.03g water/g cement was entrained, the slump of concrete mixed with 4#, 5# and 6# SAP is the same as the slump of ref concrete, and the compressive strength of concrete mixed with 4#, 5# and 6# SAP is also the same as the compressive strength of ref concrete.

Effect of CNT modified matrix of epoxy CFRPs on hydrothermal behaviour of material. Evaluation of water uptake using electrical resistance measurements

In the present work, reference and nano-modified unidirectional and quasi-isotropic, epoxy matrix, carbon fibre reinforced polymers, were exposed to distilled water at hydrothermal environment. Water uptake was investigated as a function of the CNT matrix wt-% content up to saturation level. In parallel the variation of glass transition temperature Tg was also monitored using DMA tests. The distilled water absorption process was modelled following the Fick’s law, and the experimental results found to be in very good agreement to the theoretical predictions up to saturation. During the tests, at defined time intervals, the variation of the electrical conductivity of the investigated materials was studied and a correlation between the water absorption and the variation of the electrical conductivity was established. Finally, all the reference materials and the ones concluded at the saturation stage were exposed to broadband dielectric measurements at frequency range of 0·1 Hz to 1 MHz.

Unresonant interaction of laser beams with microdroplets

The interaction of distilled water droplets (volumes of 3-4 µl) with pulsed laser beams emitted at 532 nm is described. At 532 nm the distilled water absorption is very low and the interaction of a water droplet with the laser radiation is dominated by unresonant phenomena. In this case, following the collision of the laser beam with a droplet in suspended position in air, its deformations and mechanical vibrations are produced. The conditions in which the droplets lose material as a consequence of the impact with laser beams are explored. The effects produced on the droplet were studied pulse by pulse and depend on: droplet’s content, beam wavelength, power and focusing, irradiation geometry and adhesion of the droplet to the capillary on which it is suspended. The laser pulses energies were varied in four steps: 0.25 mJ, 0.4 mJ, 0.7 mJ and 1 mJ. The laser pulse full time width at half maximum was 5ns and the typical beam waist diameter on the droplet was 90 µm; the beam had a relatively low divergence around the focus point. The droplet’s shapes evolution is visualised by recordings performed at 10 kframes/second. Following a droplet interaction with the laser beam one may also produce at a controlled moment in time, nanodroplets propagating at high (probably supersonic) speeds and microdroplets propagating at slower speeds. One may also produce suspended droplets of smaller dimensions than the initial one as well as micro/nano gas bubbles in the suspended droplet’s material/volume. In a second set of experiments the behaviour of the microdroplets of Rhodamine 6G in distilled water was recorded at high speed, at resonant interaction with similar laser pulses, and at the same power levels. The phenomena considering that the droplets contents are Newtonian liquids produced at interaction with the laser beams, are discussed.

Microwave-Irradiated Preparation of Super Absorbent Resin by Graft Copolymerization of Starch and Acrylic Acid

Graft copolymerization of acrylic acid(AA) on starch to prepare super absorbent resin (SAR) under microwave irradiation were investigated using N,N-methylene bis-acrylamide as crosslinker and potassium persulfate as initiator. The influences of the amount of initiator and crosslinker, neutralization degree of acrylic acid(AA), ratio of starch to AA, microwave power level and irradiation time on the distilled water absorption amount of resin were investigated. The results indicated that it only needed 4min under the microwave level of 231W to obtain the resin with the maximum absorption amount of 1110g×g-1, under the conditions that 0.3wt% initiator, 0.02wt% crosslinker, 60% neutralization degree of acrylic acid, the ratio of starch to acrylic acid of 0.25. Under microwave irradiation, the synthesis and drying of super absorbent resin could be completed at one step without nitrogen. Compared to conventional heating method, the methods had the striking advantages of short reaction time, simple process and low cost.

Comparison ofUlva clathrataand the kelpsMacrocystis pyriferaandAscophyllum nodosumas ingredients in shrimp feeds

Three experimental diets were formulated to contain 33 g kg−1 seaweed meals, made of wild brown algae (kelps) Macrocystis pyrifera (MAC) and Ascophyllum nodosum (ASC) or of a cultivated green alga Ulva clathrata (ULVA). The diets were fed to juvenile white shrimp Litopenaeus vannamei (1.6 g) for 28 days. Loss of dry matter (LDM) and loss of protein (LP) after 1 hour immersion in seawater, and distilled water absorption (WA) were analyzed in the pelleted diets, as well as shrimp weight gain, feed intake, feed conversion ratio (FCR), survival, protein efficiency ratio (PER) and body pigmentation. Feed intake, FCR and PER were corrected for nutrients preprandial losses in seawater. ULVA diet resulted in lower LDM, but a higher LP and also higher WA, indicating a modification of the pellet physical quality (better hydro stability). No significant differences in feed consumption and survival were found, but ULVA diet resulted in a slightly higher final weight (4.8 for ULVA versus 4.6 and 4.3 g for ASC and MAC), and better FCR (1.7 versus 1.9 and 2.1) and PER (2.0 versus 1.7 and 1.5), the differences with MAC diet being significant (Duncan, α = 0.05). Red color after cooking was markedly darker in the ULVA fed shrimp.

Comparison between Monopolar and Bipolar TURP in Treating Benign Prostatic Hyperplasia: 1-Year Report

Purpose. The major complication of traditional monopolar TURP is water intoxication due to absorption of distilled water during extended resection. A newly developed bipolar electrocautery device which uses saline irrigation decreases the risk of TUR syndrome. The aim of this study was to evaluate the efficacy and safety of this bipolar system. Methods. From April to October 2003, a total of 40 patients aged 58 to 86 years (mean: 69.3 yr) were randomized into two comparable groups; one underwent bipolar TURP and the other received monopolar TURP. Pre-operative and post-operative serum sodium concentration, hemoglobin level, resection time, blood loss and weight of specimen were evaluated. Qmax, I-PSS and bladder neck contracture were reassessed at 6-month and 1-year follow-ups. Results. There were no significant differences in hemoglobin level, blood loss, resection time or weight of specimen between the two groups. However, the difference in serum sodium level after operation was significantly greater in the monopolar group (p＜0.001). Conclusions. The bipolar electrocautery device is safer than the traditional monopolar device for the TURP procedure; the bipolar device decreases the risk of TUR syndrome and produces results similar to those obtained with the monopolar device at 6-month and 1 year follow-ups.

Pump–probe mode-mismatched thermal-lens Z scan

We report on a pump–probe mode-mismatched thermal-lens Z-scan method for the measurement of small absorption coefficients. In this method the pump light beam is focused into the sample to induce a thermal lens, which is tested by a collimated probe-light beam. Comparison between mode-matched and mode-mismatched Z-scan schemes is performed by use of a Fresnel-diffraction approximation model. This method is used to measure the absorption of distilled water and optical glass in the near-infrared and visible regions of the spectrum.

The influence of thermal history on the dynamic mechanical and dielectric studies of polyetheretherketone exposed to water and brine

The effects of thermal history on the absorption of distilled water and brine and their influence on the dynamic mechanical and dielectric properties of semi-crystalline polyetheretherketone (PEEK) are reported. Changes in the physical properties of the samples were monitored as a function of time of exposure using gravimetric measurement, dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and dielectric spectroscopy. The water and brine sorption behaviour follows a Fickian Case I process with a maximum solubility of 0.5 w/w% at 75°C. The observed sorption behaviour was independent of the salinity of the water to which the polymer was exposed. The water uptake proved to have an effect on the degree of crystallinity. It is observed that the crystallite distribution generated in the formation of the sample has a profound effect on the nature of the water uptake process and also its reversibility. During the initial stages of water uptake smaller crystallites are destroyed and these do not reform when the samples are dried. Low frequency dielectric spectroscopy exhibits a very close correlation with the gravimetric measurements and indicate that this method provides a useful non-destructive evaluation technique for the assessment of water content in filler free thermoplastics.

Water Uptake Rates by Cut Roses (Rosa hybrida) in Light and Dark1

Abstract The rate of absorption of distilled water by individual ‘Forever Yours’ cut roses was measured in continuous light (720 ft-c) and total darkness. Maximum water uptake in light (1.5 to 3.5 ml/hour) was found 24 to 48 hour (hr) after harvest followed by a gradual decline, while the lower (0.18 to 0.47 ml/hour) uptake in the dark persisted during the 120 hour study. Alternating 12 hour light and dark periods for 120 hours in a second study showed absorption rates change rapidly from light to dark or dark to light exposure. Statistical correlations were made among cut rose morphological parts and the rate of water uptake. Leaf area was found to be the factor most closely associated with water uptake in both light and dark. Anatomical studies revealed overall tissue degradation in rose stems kept in distilled water 5 days.

The kinetics of capillary absorption of liquids in a constant magnetic field

The method and technique of experimental study is described with respect to the kinetics of capillary absorption of distilled water and a 10% aqueous solution of NaCl by quartz sand in a nonuniform magnetic field. The results of this experimental study are given.

Changes in rate of intestinal absorption of sodium chloride solutions.

Absorption of distilled water, NaCl solutions and 1.0% glucose solution was studied in acute experiments in dogs anesthetized with sodium pentobarbital. A reduction in rate of absorption in consecutive 10-minute periods was observed for distilled water and solutions of 0.2% NaCl, 0.9% NaCl and 1.0% glucose. The degree of change in rate of absorption is inversely proportional to the concentration of test solution for distilled water, 0.2% NaCl, 0.9% NaCl and 1.0% NaCl. The inhibiting effect of hypotonic NaCl solutions on absorption is of local origin and is reversed in part by 2.0% NaCl solution.

THE ACTION OF MAGNESIUM SULPHATE ON THE INTESTINE OF THE CAT

1. Isotonic MgSO4 slows the absorption of isotonic NaCl solutions in the intestine of the cat. It does not influence the absorption of glucose solutions. It does delay slightly the absorption of distilled water.2. Isotonic MgSO4 is no more irritating to the colon than isotonic NaCl as evidenced by histological studies. Its action in producing purgation is probably that of diminishing absorption and thereby producing mechanical stimulation for defæcation by the increased bulk.3. MgSO4 in small doses produces loose and watery stools in cats for several days. This may be due to its effect in slowing the absorption of other crystalloids.4. Solutions of NaCl are best absorbed from the ileum; of glucose, best from the jejunum in cats.5. Decapitate cats cannot be considered to be completely normal with regard to intestinal motility. Washing and excessive handling of the colon tend to make it irritable and give inconsistent results in acute experiments.