Hydration Time Research Articles

Safety in immediate reconstitution of poly-l-lactic acid for facial biostimulation treatment.

Poly-L-lactic acid is presented as freeze-dried preparation of 150mg per vial and, according to consensus, the recommendation on your preparation is hydrate in sterile water for injection (SWFI) or bacteriostatic water at room temperature for ≥24hours. (J Drugs Dermatol; 2014;13:s44) However, in these long periods of hydration, it is time-consuming and costly for the physicians. To demonstrate the safeness of immediate reconstitution of facial biostimulation treatment with PLLA. A clinical prospective study with 26 Latin American female patients, aged between 27 and 80years, complaining of facial laxity of treated with immediate PLLA reconstitution. One PLLA vial was injected per session in 12mL total dilution. All patients had their pictures taken before and after the treatment in Photo Analysis Program Vectra 3D (Canfield® ). A follow-up 90days was performed. The total of 58 facial applications of PLLA was reported in female patients with a mean age 52.62 (±13.46) years. Pain was reported in 17 injections (29.31%) and ecchymosis in 6 (10.34%). Also, 2 patients (3.44%) developed a nodule. None of the patients presented significant bruising, edema, or papules formation. Despite the literature declare that a longer hydration times (up to 48hours) have been shown to reduce the risk of nodule formation (Aesthet Surg J; 2011;31:95), our study demonstrated the safeness of injection with immediate reconstitution and a very low adverse events rate. Immediate PLLA reconstitution is a great asset for physicians, injections in account of being less laborious, less time-consuming, and reducing product loss for the injector.

Controllable synthesis of terminal carboxyl hyperbranched polyester and their retarding effect on concrete

Concrete retarders could efficiently extend the hydration time of cement and maintain the plasticity of concrete slurry. However, some inherent shortcomings, such as a short setting time and poor compatibility, severely limits their application. To solve these problems, in this work, a series of carboxyl-terminated hyperbranched polymers (CTHP) were controllably synthesized and their retarding effects on the concrete setting were investigated. The results showed that the final setting time of concrete was increased by nearly 4 times as the addition amount of third generation CTHP was 1.5%, demonstrating an excellent retarding effect. Furthermore, the compressive strength was increased by 43% after 7 d of curing. The results of resistivity and Zeta potential demonstrated that CTHP could change the surface charge density of cement particles and affect the flocculation of cement particles and thus extend the retarding time. The results of Tg、XRD and SEM demonstrated that the CTHP could induce a decrease in the content of Ca(OH)2 and an increase in the content of ettringaite (AFt) during the hydration procedure, drastically enhancing the strength of the concrete. These CTHP would demonstrate the enormous potential to commercial concrete for the rapid demand in the engineering field.

Using the Particle Model to predict electrical resistivity performance of fly ash in concrete

The electrical resistivity performance of fly ash in concrete is not easy to predict due to the diverse sources of fly ash and their varying reactivity. Electrical resistivity gives direct evidence of the rate of corrosion within the concrete and provides indirect clues into the fluid transport into the material. This paper aims to develop predictive models for the electrical resistivity of fly ash concrete by applying the Particle Model. The Particle Model rapidly examines individual fly ash particles without human intervention and is used to derive predictive models for 20% and 40% fly ash replacement levels in concrete at seven different periods of hydration. The R-squared values of predictive models in the Particle Model show significant improvement over using the classification method based on Class C and F for both fly ash replacement at all investigated time periods. The derived predictive models are able to accurately estimate the electrical resistivity within +/- 10% for 80% of all measurements at 20% fly ash replacement and within +/− 10% for 75% of all measurements at 40% fly ash replacement. These investigations provide important insights into how the Particle Model can help predict the electrical resistivity of fly ash concrete even at different mixtures and hydration times.

Hydration time influences microcrustacean hatching in intermittent wetlands: in situ and ex situ approaches

Organisms living in intermittent wetlands present adaptations to cope with the inundation-desiccation process. Microcrustaceans are commonly found in intermittent wetlands because they present reproductive strategies able to synchronize with the hydroperiod. To know the dynamic of the microcrustaceans, that inhabit these wetlands of the subtropical coastal plain, which predominate the Pampas biome in Brazil, we analyzed the influence of hydration time and temperature on the hatching of microcrustaceans, comparing in situ and ex situ approaches. We followed hatching 34 days after in situ flooding and tested three temperatures (10, 15, and 20°C) 30 days after laboratory flooding. In both approaches, we classified the hydration time as the beginning, middle, and end of the hydroperiod. We recorded a total of 41 taxa distributed in Cladocera (26 taxa), Ostracoda (8), Copepoda (3), Anostraca (1), and Conchostraca (1). We observed that in situ hydration time was the most important factor for hatching. Ex situ hydration time was also important, but the increase in temperature positively affected the hatching of organisms. We also found that in both approaches, the beginning of hydration time is the most important period for the hatching of microcrustaceans.

Understanding handling performance of rugby balls under wet conditions: analysis of finger-ball friction

ABSTRACT This paper presents work with the aim of investigating the effect of moisture on the skin frictional behaviour of human finger-pads in contact with rugby balls. During sports activities, human body experiences high volumes of thermoregulatory sweating as a result of achieving body’s temperature balance. Consequently, sweating alters human skin properties and contact conditions between hand skin and sports equipment, and may adversely affect exercise/sports performance. In this work, a rugby ball passing test under wet conditions was conducted to examine the influence of skin hydration on rugby ball handling performance. Then, a comprehensive study was carried out to assess skin structures, frictional properties and contact areas of the interface between human finger-pads and flat surfaces at different moist conditions. It was found that the handling performance of rugby balls is strongly associated with the skin moisture level. The experimental results of the skin friction study showed that the skin friction coefficient changes with hydration time following a “bell-shape” curve. It also showed that the corresponding thickness of the stratum corneum of the examined fingers increased due to the transmission of water in skin tissues. This leads to an increase in the contact area and friction force with hydration time.

Characterization and mechanism of early hydration of calcium aluminate cement with anatase-TiO2 nanospheres additive

Aiming to shorten the hydration time of calcium aluminate cement (CAC) at 20 ℃, anatase-TiO2 nanospheres (nano-TiO2) additive at the content range from 1 to 5% (mass percent) was added in CAC with water to cement ratio (w/c) of 0.4. Isothermal calorimetry in combination with conductimetric measurements, TG-DTA, XRD, optical microscopy and SEM were adopted to investigate the heat change, ion concentration change, phase and microstructure of CAC samples during the early hydration. The results show that the main hydration products of CAC added with nano-TiO2 change from CaAl2O4·10H2O (CAH10) and Ca2Al2O5·8H2O (C2AH8) to CAH10, with no presence of other new phases. Nano-TiO2 can promote the hydration process of CAC. However the promotion effect varies depending on its content. Especially, the end time of induction period and early hydration period with 3% nano-TiO2 addition are shortened by 4 h and 6 h, respectively. Based on this, the hydration promotion mechanism of nano-TiO2 additive is further clarified from the point of vacancy and nucleation.

Evaluation of hydrophylic montmorillonite nanofluids and xantane gum in saline environment

With an estimated increasing oil demand in the coming decades, the need to explore non-applicable areas is intensified, and associated with them, before the high exploration costs, the need to improve available technologies. In this sense, in the last decade, the application of nanoparticles to improve drilling fluids has been intensified. In this scenario, montmorillonite nanoclays and xanthan gums were little explored for the development of nanofluids. In this work, the influence of hydrophilic nanoclay on the rheological parameters of xanthan, sodium and calcium chlorides solutions was verified. For this, first, the clay was characterized by XRD, XRF and TGA. Then, maintaining constant the salt and xanthan concentrations, the influence of the variation in the concentration of nanoclay on the rheology of the solution was evaluated. Then, keeping the components concentrations constant, the influence of temperature was verified and then the hydration time on the rheology of the mixture. Finally, to assess the interaction of the mixture, it was verified the Electrical Conductivity and the Potential Zeta, varying the concentration of the nanoclay and the hydration time. It was concluded that: for certain nanoclay concentrations, there is an improvement in the rheology of xanthan solutions; an addition of nanoclay favors rheology in the mixture of xanthan with increased temperature; hydration time does not affect the rheology of the nanofluid; there is interaction between nanoclay and xanthan.

Carbonation of CEM III mortar – Influence of impure CO2 (with SO2 and NO2) and chloride rich brine

With regard to CCS (carbon capture and storage) technology, the interaction was investigated of mortar specimen (produced with CEM III) with CO2, featuring small amounts of SO2 and NO2 (each about ~ 70 ppm) in the presence of chloride-rich brine at 333 K and 16 MPa. Chemical and mineralogical properties of the cement were characterized. The mineralogy of hardened cement pastes was evaluated by PXRD (powder X-ray diffraction). DSC-TG (differential scanning calorimetry with thermogravimetry) measurements were carried out and coupled with mass spectrometry (MS). For the evaluation of the mechanical properties mortar prisms (160 mm × 40 mm × 40 mm) were produced according to the German standard DINEN196–1:2005. After a hydration time of 29 days, the samples were treated with CO2 in chloride-rich brine at 333 K and 16 MPa for ~ 35 days. The compressive strength of the samples were investigated before and after treatment with impure CO2 and chloride-richbrine. The mortar specimens were treated with CO2 (accompanied with SO2 and NO2) in chloride-rich brine (230 g/L NaCl, 15 g/LCaCl2, 5 g/LMgCl2) at 333 K and 16 MPa for ~ 35 days. After 35 days in an autoclave the samples seemed to be undamaged by visual inspection. Loss of compression strength was not observed. Due to these promising results further investigation should be considered of the chosen cement system.

Insights into the properties and chloride binding capacity of β-hemihydrate in the presence of slag powder and white calcium aluminate cement

Calcium chloride (CaCl2) as a common concomitant in flue-gas desulfurization gypsum has a great negative impact on gypsum-based construction materials. Chloride binding in the form of Friedel's salt in the gypsum-dominating system is of great significance, but the feasibility of this approach has not yet been systematically clarified. In this paper, granulated blast-furnace slag (GBFS) powder and white calcium aluminate cement (CAC) were used as the components to explore their roles on the properties and chloride binding capacity of β-hemihydrate. Experimental results prove that CAC significantly improves compressive strength, water resistance, and chloride binding capacity of hardened paste. The XRD, DTG, SEM-EDS and thermodynamic modeling confirm that Friedel's salt forms in this system even at an early hydration time of 30 min. Mercury intrusion porosimetry and SEM results verify that the use of CAC decreases the volume of the pores in the 0.1–100 μm range. Thermodynamic modeling outcomes are consistent with the experimental data helping to explain the hydration and evolutions of β-hemihydrates in the presence of CaCl2, GBFS, and CAC at early hydration ages.

Rheological assessment of the interaction between hydrophobic nanoclay and xanthan gum in saline environment, for application in drilling nanofluid

In the last decade, exploration in high temperature and pressure wells has motivated the improvement of drilling fluids with the application of nanoparticles. In this context, nanoclay, the most available of nanoparticles, has been applied in the development of nanofluids, mainly associated with polymers. In parallel, among the polymers used, xanthan gum has been little explored for this purpose. In this work, the interaction between xanthan gum, hydrophobic nanoclay, sodium and calcium chloride and their influence on the rheological parameters of the mixture was evaluated in solution. The influence of temperature and hydration time on the rheological parameters of the mixture was also evaluated. For this purpose, nanoclay was first characterized with XRF, XRD and TGA. Then, a complete factorial design 24 was adopted, varying the concentrations of nanoclay, xanthan, sodium and calcium chlorides. Third, a Doehlert Matrix of the 7x5x3 type was adopted, varying the concentrations of nanoclay, xanthan and temperature, with the concentrations of the constant salts. In the fourth, select the effect of the hydration time on the color rheological parameters. Finally, Conductivity and Potential Zetas of sizes were verified, varying the concentration of the components and the hydration time of the mixtures. It was concluded that the interactions between the components of the mixture do not stabilize; the temperature, the salts have no significant influence on the rheology of the mixture; nanoclay in concentrations not exceeding 5% (m/v) interacts with the Minimum Shear Stress; the rheological parameters stabilize after 96h of hydration.

Study on desulfurization mechanism of adsorbents prepared by high ratio circulating fly ash and lime

Under the conditions of low temperature, low humidity and different mixture ratios, a variety of adsorbents were prepared by using a new preparation method and the Shendong high ratio circulating fly ash of the No Gap Desulfurization process was chosen as raw material. The desulfurization performance of adsorbents were characterized by the fixed-bed desulfurization reactor, and the effects of desulfurization process conditions (moisture content, mixing ratio, desulfurization temperature and initial concentration of SO2) on desulfurization removal efficiency have been experimentally investigated. The optimum desulfurization process conditions were found under the conditions of the hydration time was 3 h, moisture content was 15%, desulfurization temperature was 70 °C and initial concentration was 200 μL/L, and at this time the effective desulfurization time was 93.95 min, the maximum desulfurization efficiency was 99.12%. Through systematic analysis of the whole process of desulfurization reaction, it was concluded that the desulfurization efficiency was controlled by the desulfurization reaction rate and gas diffusion rate at the initial and later stages of the reaction respectively. Reducing the difference between the desulfurization reaction rate and gas diffusion rate can improve the desulfurization efficiency, which laying a theoretical foundation to improve the desulfurization efficiency of No Gap Desulfurization process.

Intranasal Niosomal In Situ Gel as a Promising Approach for Enhancing Flibanserin Bioavailability and Brain Delivery: In Vitro Optimization and Ex Vivo/In Vivo Evaluation.

Flibanserin (FLB) is a multifunctional serotonergic agent that was recently approved by the FDA for the oral treatment of premenopausal women with hypoactive sexual desire disorder. FLB is a centrally acting drug that has a low oral bioavailability of 33% owing to its exposure to the hepatic first-pass effect, as well as its pH-dependent solubility, which could be an obstacle hindering the drug dissolution and absorption via mucosal barriers. Thus, this work aimed at overcoming the aforementioned drawbacks and promoting the nose-to-brain delivery of FLB via the formulation of an intra-nasal in situ niosomal gel. The Box–Behnken design was employed to study the impact of Span® 85 concentration (X1), hydration time (X2), and pH of the hydrating buffer (X3) on the vesicle size and drug entrapment. The optimized formulation exhibited a spherical shape with a vesicular size of 46.35 nm and entrapment efficiency of 92.48%. The optimized FLB niosomes integrated into gellan gum-based in situ gel exhibited enhanced ex vivo permeation and improved plasma and brain concentrations after nasal administration in rats compared to raw FLB. These findings highlight the capability of the proposed intra-nasal FLB niosomal in situ gel to boost the drug bioavailability and to promote its direct delivery to the brain.

Dipolar interactions among magnetic dipoles of iron oxide particles dispersed in mili-size hydrogel beads

The recently published Mean Field Interacting Superparamagnet Model (MFISP model), which introduces the effective demagnetizing factor NE, is tested in specimens having a random-like spatial distribution of magnetic nanoparticles, where different hierarchies of clustering are present. These specimens are ferrogel PVA/iron oxide beads synthesized by a one-pot route, having spheroidal shapes and sizes of about 1 mm, and chain and disk-like arrays (superstructures) of beads. Raman analyses indicated that magnetic nanoparticles are composed by a mixture of magnetite and maghemite. Beads swell 208% by hydration in about 40 min.The increase of the ac susceptibility as a function of hydration time closely reflects the effect of bead swelling, in agreement with the expected diminution of dipole–dipole interactions. Measured susceptibility is analyzed in terms of the susceptibility χ of non-interacting particles and the effective demagnetizing factor NE of the specimen, which depends on swelling. The Specific Absorption Rate of electromagnetic power by the beads grows with the hydration time in agreement with ac susceptibility behavior.For long hydration times susceptibility and high field magnetization decrease. This is explained by the occurrence of oxidation of magnetite/maghemite to hematite.Isothermal magnetization experiments are performed on each superstructure in two perpendicular principal directions each. Results are consistently described with the MFISP model by considering two hierarchies of clustering: beads themselves and clusters within the beads.From the whole set of experiments, it is possible to estimate values for the volume fractions of particles in clusters and clusters in beads, given by xpc=0.46(15) and xcb=0.16(5). The susceptibility of non-interacting particles, χ=13(4), is also obtained, which results about five times larger than the measured (apparent) one.The MFISP model proves to be a convenient and efficient tool for the analysis of magnetization studies of complex 3d dispersions of magnetic nanoparticles, allowing an experimental determination of relevant physical information, otherwise not accessible by magnetic measurements.

Effects of Nano Silica on oil well cement slurry charactreistics and control of gas channeling

In this work, different percentages of Nano silica additive have been added to the two basic drilling cement samples, with 90PCF and 118PCF densities. The results showed that not only has the rate of gas migration in cement decreased, but also other conventional properties of cement, including strength, have improved in some cases. Possible and testable percentages of Nano additive were 0.11, 0.22, 0.33 and 0.55 percent. Measurements by the SGSA device have shown a reduction in the transient time or critical time of cement hydration. In 90PCF slurry, the transient time from 120min to 55MIn has been reduced by adding 0.33% Nano silica. Compressive strength increased from 723psi to 1239psi. The FMA also showed a decrease in fluid migration from 38ml to 15ml. Triaxial experiments have shown an increase in Peak Stress from 22MPa to 25 MPa. In slurries with a density of 118PCF, adding 0.11% Nano silica, the transient time was reduced from 170min to 100min. The compressive strength has been increased from 2089psi to 3020psi. The rate of fluid migration in cement has decreased from 4ml to 0ml. Also, the peak stress rate has increased from 60MPa to 71MPa. In addition, the XRD experiment emphasized the improvement of the cement microstructure after the addition of Nano-silica

Development and Characterization of a Novel Peptide-Loaded Antimicrobial Ocular Insert.

Infectious ocular keratitis is the leading cause of blindness worldwide. Bacterial resistance to classical pharmacological treatments raised the interest of researchers towards antimicrobial peptide (AMP)-based therapy. hLF 1-11, a synthetic antimicrobial peptide derived from the N-terminus of human lactoferrin, proved effective against different bacteria and yeast but, like all proteinaceous materials, it is unstable from chemical, physical, and biological points of view. In this study, new freeze-dried solid matrices containing mucoadhesive polymers were prepared and characterized in terms of rheology, hydration time, bioadhesion, drug content, and in vitro release. The formulation HPMC/T2/HA/hLF 1-11fd was selected for the delivery of hLF 1-11, since it showed good drug recovery and no chemical degradation up to at least 6 months (long-term stability). Furthermore, the HPMC/T2/HA/hLF 1-11fd matrix allowed for the release of the drug in a simulated physiological environment, linked to an optimal hydration time, and the peptide antimicrobial activity was preserved for up to 15 months of storage, a very promising result considering the chemical liability of proteinaceous material. For its properties, the freeze-dried matrix developed in this study could be a good platform for the delivery of antimicrobial peptides in the precorneal area to treat infectious phenomena of the ocular surface.

Visualization and quantification of pore structure of oil-well cement slurry in liquid-solid transition stage using high-resolution computed tomography

Understanding the pore structure of oil-well cement slurry during early hydration is key to resolving short-term gas migration in natural gas wells. This study evaluated the three-dimensional microstructure and pore structure of oil-well cement slurry during early hydration using in situ high-resolution X-ray computed tomography and image reconstruction techniques. Experimental results showed that in the initial hydration stage the microstructure of the oil-well cement slurry comprised ‘dispersed particles’. When the hydration rate increased, some hydration products formed between the dispersed particles, and the microstructure of the slurry changed from a ‘dispersed particles’ structure to an ‘agglomerated skeleton’ structure. Furthermore, when the hydration time increased from 180 to 600 min, the porosity of the slurry decreased from 11.46% to 10.14% (a 11.52% decrease), the porosity of pores with volumes of 201 or more voxels reduced from 2.96% to 1.81% (a 38.83% decrease), and the connected porosity decreased from 4.47% to 2.26% (a 49.47% decrease). These results indicate that during early hydration, the formation of hydration products reduces the pore volume and cuts off some connected pores to produce many pores with small volumes. Based on the Kelvin−Laplace equation, the reduction in pore size increases the capillary pressure of the pore solution and shifts the weight of the pore solution acting on the agglomerated skeleton to reduce the hydrostatic pressure of the slurry. This study further proves that the pore structure of oil-well cement slurry is a key factor in reducing hydrostatic pressures and enabling short-term gas migration.

Swelling pressures and hydration times in a clay seal

Underground repositories for nuclear fuel waste will eventually become filled, and access shafts will have to be sealed. In many international studies, the preferred sealant is a compacted sand–bentonite mixture in which montmorillonite in the bentonite swells as it absorbs groundwater and develops swelling pressure. Lowered porosities in the bentonite lead to reduced hydraulic conductivity. Sealing is most effective when the seal is saturated and swelling pressure has been maximised. The time required to reach complete hydration is important. This paper describes the development of swelling pressures during hydration of a field-scale shaft-sealing experiment at Canada’s underground research laboratory. Numerical modelling used the finite-element program Code_Bright and hydro-mechanical parameters from laboratory tests to determine time-dependent porosities, total pressures and degrees of saturation in the full-scale field project. Data from laboratory-scale ‘wetting’ tests on specimens of seal material were then used in models by Liu and Dueck and Börgesson to evaluate changes in swelling pressures with time. Six years of data from field instruments indicate that the seal was functioning as designed. In the future, when the seal becomes fully hydrated and reaches stress equilibrium, the modelling suggests that swelling pressures in the seal will be in the range of 0.43–0.86 MPa. This is broadly similar to the value of 0.8 MPa suggested by a separate series of laboratory swelling tests. Full saturation and maximum swelling pressure can be expected in 17–19 years after the seal has been completed.

Artificial neural network (ANNs) and mathematical modelling of hydration of green chickpea

The present study was aimed to model the hydration characteristics of green chickpea (GC) using mathematical modelling and examine predictive ability of artificial neural network (ANN) modelling. Hydration of GC was performed at different temperatures 25, 35, 45, 55 and 65 °C. Different mathematical models were tested for the hydration at different temperatures. In ANN modelling, the hydration time and hydration temperature were used as input variables and moisture ratio, moisture content and hydration ratio were taken as output variables. Peleg model best described the hydration behavior at 25 °C; while hydration at high-temperature was better described by Page model and Ibarz et al. model. The optimum temperature obtained for hydration was 35 °C. Effective mass diffusion coefficient (De) increased from 1.55 × 10-11-1.79 × 10-9 m2/s with the increase in the hydration temperature. The low activation energy (39.66 kJ/moL) shows the low-temperature sensitiveness of GC. Low temperature hydration (25 °C) required higher time (>200 min) to achieve the equilibrium moisture content (EMC), however high temperature hydration (35–65 °C) reduced the EMC time (150 min). ANN was used to predict the hydration behavior and K fold cross validation was performed to check the over fitting of ANN model. Results show that the LOGSIGMOID transfer function showed better performance when used at the hidden layer input node in conjunction to both PURELIN and TANSIGMOID. TANSIGMOID was found suitable for moisture ratio (MR) and hydration ratio (HR) prediction, as opposed to PURELIN for moisture content (MC) data. Satisfactory model prediction was obtained when the number of neurons in the hidden layer for MC, MR and HR was 12, 8 and 15, respectively. Mathematical and ANN modelling results are useful to improve/predict the MC, MR and HR during hydration process of GC at different temperature and other similar process.

Standardization Study of Extraction Tests over Hydration Time for Hydrogel Ophthalmic Lenses

Standardization Study of Extraction Tests over Hydration Time for Hydrogel Ophthalmic Lenses

Study on the hydration and moisture transport of white cement containing nanomaterials by using low field nuclear magnetic resonance

In order to characterize the hydration and moisture transport process of white cement containing nano-SiO2 (NS) and nano-Al2O3 (NA), the transverse relaxation time (T2) spectrum signals of the cement paste and mortars were measured by low field nuclear magnetic resonance (LF-NMR). The effect of NS and NA on the T2 spectrum, T2 geometric average values, and porosity of cement paste from 15 min to 72 h of hydration were studied. Moreover, the compressive strength, flexural strength, and pore structure tested by mercury intrusion porosimetry were given. Furthermore, the variation in gel pore and capillary pore of mortar as a function of moisture transport, including drying and moisture absorption (deionized water and 3% NaCl solution) process, was revealed. The results indicate that the induction time of hydration is shorten and the early porosity is reduced by introducing NS and/or NA. In the case of drying, free water evaporates from large pores to small pores, and the water in the gel pore cannot be extracted during drying. With respect to moisture absorption, the incorporation of 1 wt% NS reduces the number of gel pores, the number of capillary pores is decreased by adding 0.5 wt% NS and 0.5 wt% NA, and the mortar containing 0.5 wt% NS and 0.5% NA shows the lowest hygroscopic rate.