Hydration Procedure Research Articles

Study of the Hydration Process of Synthetic Preparation of Ettringite by Direct Addition of Aluminum Sulfate and Calcium Hydroxide

The stability of ettringite as high-watery mineral is highly dependent on the ambient temperature. Under standard laboratory conditions, onset of decomposition of this phase occurs at temperature of 80°C already and the theoretical temperature of the complete decomposition of ettringite is 180°C. Ettringite decomposition can occur at significantly different temperatures under humidity conditions other than the laboratory ones. Within the work verification of the possibility of synthetic preparation of ettringite by direct addition of aluminum sulfate, Al2(SO4)3·18H2O, and calcium hydroxide, Ca (OH)2, as an alternative method to the yeelimite hydration procedure was carried out. The stability of the resulting systems was examined in two different environments, namely in a laboratory environment and the environment of saturated water vapour. The phase composition of the samples was determined by X-ray diffraction (XRD) analysis, thermal analysis and scanning electron microscopy (SEM).

Direct shear testing of GCLs at elevated temperature and in a non-standard solution

The objective of this study was to develop, verify, and assess a direct shear apparatus to measure the internal shear strength of geosynthetic clay liners (GCLs) when exposed to elevated temperature and non-standard hydration solutions. Shear boxes were developed to facilitate testing 300 mm square and 150 mm square specimens. Preliminary experiments documented the effectiveness of a GCL gripping system and a two-stage hydration procedure. Direct shear experiments were performed to evaluate the new apparatus with respect to the following variables: (i) specimen size; (ii) GCL peel strength; (iii) GCL heat treatment; (iv) test temperature; and (v) hydration solution. Direct shear results were verified via comparison to literature, which also supported the use of 150 mm square GCL specimens to measure internal shear behavior and shear strength. Shear tests on heat-treated and non-heat-treated GCLs at 20°C and 80°C yielded a 40% reduction in internal peak strength with increase in temperature. Hydration in a high-alkaline synthetic mining solution indicated a loss in peak strength with increasing hydration times from 15 to 60 days. A systematic reduction in peak and large-displacement shear strength with increasing normal stress was observed for 60 days’ hydration in the alkaline solution relative to hydration for 4 days in de-ionized water.

Endoglin based in vivo near-infrared fluorescence imaging of tumor models in mice using activatable liposomes

BackgroundEndoglin (CD105) is overexpressed on tumor cells and tumor vasculatures, making it a potential target for diagnostic imaging and therapy of different neoplasms. Therefore, studies on nanocarrier systems designed for endoglin-directed diagnostic and drug delivery purposes would expose the feasibility of targeting endoglin with therapeutics. MethodsLiposomes carrying high concentrations of a near-infrared fluorescent dye in the aqueous interior were prepared by the lipid film hydration and extrusion procedure, then conjugated to single chain antibody fragments either selective for murine endoglin (termed mEnd-IL) or directed towards human endoglin (termed hEnd-IL). A combination of Dynamic Light Scattering, electron microscopy, cell binding and uptake assays, confocal microscopy and in vivo fluorescence imaging of mice bearing xenografted human breast cancer and human fibrosarcoma models were implemented to elucidate the potentials of the liposomes. ResultsThe mEnd-IL and hEnd-IL were highly selective for the respective murine- and human endoglin expressing cells in vitro and in vivo. Hence, the hEnd-IL bound distinctly to the tumor cells and enabled suitable fluorescence imaging of the tumors, whereas the mEnd-IL bound the tumor vasculature, but also to the liver, kidney and lung vasculature of mice. ConclusionsThe work highlights key differences between targeting vascular (murine) and neoplastic (human) endoglin in animal studies, and suggests that the hEnd-IL can serve as a delivery system that targets human endoglin overexpressed in pathological conditions. General significanceThe endoglin-targeting liposomes presented herewith represent strategic tools for the future implementation of endoglin-directed neoplastic and anti-angiogenic therapies.

Membrane properties of giant polymer and lipid vesicles obtained by electroformation and pva gel-assisted hydration methods

Giant Unilamellar Vesicles (GUV) are the most commonly used biomimetic membrane model. Their production in physiological conditions through the well-known electroformation process is complex and other gel-assisted hydration procedures have recently emerged to circumvent some limitations of the process. In this work, the membrane physical properties of Giant Polymer Unilamellar Vesicles (Polymersomes) and lipid vesicles (Liposomes) obtained from the gel-assisted hydration procedure and electroformation, have been evaluated thoroughly by different techniques: micropipettes aspiration (MPA), Fluorescence Recovery After Photo Bleaching (FRAP) and Laurdan Generalized Polarization (GP). The study was performed on GUVs made of either phospholipids (POPC and DPPC) or amphiphilic copolymers based on Poly(dimethylsiloxane) and poly(ethyleneoxide). A significant deviation of stretching modulus, lateral diffusion coefficient and membrane packing was observed for GUVs formed by the PVA gel-assisted hydration method compared to the classical electroformation process. We were able to show that this deviation was due to the presence of PVA chains in the membrane and in the suspending medium. Globally our findings reveal that particular attention has to be paid on the gel assisted hydration process as the vesicles obtained present altered mechanical behaviour.

The role of hydration on the cooking quality of bran-enriched pasta

Hydration of multi component systems, such as pasta enriched with wheat bran, is a complex phenomenon due to water competition in the mixture. The influence of the hydration method on the quality of wheat pasta loaded with wheat bran is addressed in this work. In particular, spaghetti containing wheat bran were produced by two different hydration methods: the durum wheat semolina and bran were first mixed together and then hydrated (-BT); durum wheat semolina and bran were separately hydrated and then mixed together (-BS). Two different concentrations of wheat bran, 20 g/100 g and 25 g/100 g, were prepared. Size exclusion-HPLC analysis was performed to investigate conformational polymeric changes of how the gluten network is affected by the hydration procedure. Sensory properties and the cooking quality of the samples were also assessed. Results suggest that the hydration method markedly affects the formation of disulphide bonds, suggesting that separate hydration increases the number of disulphide bonds, the strength of the gluten network. As a matter of fact, samples obtained by separated hydration recorded a significant improvement of both sensory attributes and cooking quality parameters as compared to samples obtained by simultaneous hydration.

Development of artificial intelligence based systems for prediction of hydration characteristics of wheat

Hydration characteristics (moisture content, moisture ratio and hydration rate) of wheat kernel during soaking process were studied and simulated. Hydration procedure was performed at five different experimental water temperatures (30, 40, 50, 60 and 70 (°C)) with respect to hydration time changes. Hydration characteristics of samples were modeled using one of the most popular simulation frameworks of artificial intelligence, adaptive neuro-fuzzy inference system (ANFIS). A comparison was also made between results of the best developed ANFIS model and those of the another well-known artificial intelligence technique, artificial neural network (ANN). The hydration temperature and time were used as input parameters and moisture content, moisture ratio and hydration rate were taken as output parameters of the intelligent modeling frameworks. To attain the best model with the highest predictive ability, developed models were compared based on statistical parameters of coefficient of determination, root mean square error and mean relative deviation modulus. According to the results, although the best framework of both ANFIS and ANN were able to accurately predict hydration characteristics, the best ANN simulation framework with a simple structure (2–4–3) was easier to use than the ANFIS with three different structures. ANN surface plots also illustrated that increasing the hydration temperature and time increased moisture content and decreased moisture ratio. Moreover, ANN modeling results indicated that the hydration rate increased in the initial and decreased in the middle and final phase of hydration procedure.

Tracing hydration feature of aluminophosphate cementitious materials by means of electrochemical impedance method

In this paper, electrochemical impedance spectroscopy (EIS) is adopted as a nondestructive testing method for tracing the hydration procedure of aluminophosphate cementitious (APC) materials. A newly proposed electrochemical model is used to explain the hydration related features. The experimental results show that the electrochemical impedance behavior of APC varies with the process of hydration, along with hydration time increasing, as the ion transport processes resistance (Rct1, the parameter of the electrochemical impedance model) increasing gradually. In addition, Rct1 has a similar growth law with compressive strength of APC during whole hydration procedure. Moreover, Rct1 and high-frequency semicircle form its Nyquist curve reduces gradually with water-cement ratio increasing; and after the contrastive investigation on different boric acid content of APC impedance spectroscopy, it can be obtained that Rct1 need more time to reach steady with boric acid content increasing. The experimental results show that electrochemical impedance method is reasonable for tracing the hydration feature of APC materials.

Perceptions of health professionals on subcutaneous hydration in palliative care: A qualitative study

Background: Evidence indicates that hypodermoclysis is as safe and effective as intravenous rehydration in the treatment of the symptomatology produced by mild to moderate dehydration in patients for whom oral route administration is not possible. However, the knowledge about the use of the subcutaneous hydration and its correlates is still limited. Aim: To explore the perceptions, attitudes and opinions of health professionals in palliative care on the administration of subcutaneous hydration. Design: This is a qualitative focus group study with health professionals of palliative care. Four focus groups were carried out until data saturation. A qualitative content analysis was performed. Setting/participants: A total of 37 participants, physicians and nurses, were recruited from different services of palliative care in Spain. Results: In all, 856 meaning units were identified, from which 56 categories were extracted and grouped into 22 sub-themes, which were distributed among four themes: ‘factors which influence the hydration decision’, ‘factors related to the choice of the subcutaneous route for hydration’, ‘the subcutaneous hydration procedure’ and ‘performance guidelines and/or protocols’. Conclusions: Variables which most often influence the use of subcutaneous route to hydration are those that are linked to the characteristics of the patient, the team and the family, and other like the context and professionals’ subjective perceptions about this medical practice.

Temperature evolution of hydration shells in solid DNA didecyldimethylammonium chloride complex studied by 1H NMR spectroscopy

In the case of DNA and its derivatives hydration effect are of paramount importance for many characteristics. Despite years of extensive research this phenomenon is not completely understood yet. A model DNA–lipid complex with didecyldimethylammonium chloride was subjected to gaseous phase hydration procedure. Using 1H NMR spectroscopy a qualitative change in hydration pattern was identified when the material was conditioned in atmosphere of 10.1% of relative humidity. At the threshold hydration level on the top of the first hydration shell appear water molecules that may be attributed to the second hydration shell. This value is lower, that cited in the bibliography as the saturation point of the first hydration level.

The interaction of H3PO4and steam with PBI and TPS polymeric membranes. A TGA and Raman study

Thermogravimetric analysis (TGA) and Raman spectroscopic experiments were carried out in order to study the interaction of H3PO4 and steam with the chemical structure of polybenzimidazole (PBI) and pyridine bearing aromatic polyethers (TPS). The interaction of the polymers with H3PO4 causes a blue Raman shift on the imidazole and the pyridine bands, which is larger for the imidazole ring. It has been found that one H3PO4 molecule is needed to neutralize one imidazole group, while ca. five H3PO4 molecules are necessary for full protonation of the pyridine group. This observation is reflected on the hydration procedure of the imbibed membranes at high temperatures (150–170 °C) as this was studied by TGA. At low acid doping levels (130–150 wt%) the hydrolysis of pyrophosphoric acid into ortho-phosphoric acid is not reversible in the case of PBI, thus indicating that the chemical structure influences the chemical equilibrium of the hydrolysis reaction. The evaporation rate of H3PO4 increases with increasing steam partial pressure and is lower in the case of PBI than in TPS. Nevertheless in all cases the evaporation rate is by a factor of two lower than that of the pure phosphoric acid under the same steam partial pressure.

Thermal cracking analysis of concrete with cement hydration model and equivalent age method

In this research, a developed microstructural model of cement particles was presented to describe the cement hydration procedure. To simplify the hydration process, the whole hydration was analyzed in a series of sub-steps. In each step, the hydration degree, as well as the microstructural size of the hydration cell, was calculated as a function of the radius of the unreacted cement particles. With the consideration of the water consumption and the reduction of the interfacial area between water and hydration products, the micro-level expressions of the cement hydration kinetics were established. Then the heat released and temperature history of the concrete was carried out with the hydration degree obtained from each sub-steps. The equivalent age method based on the Arrhenius law was introduced in this research. Based on the equivalent age method, a maturity model was applied to describe the evolution of the mechanical properties of the material during the hydration process. The finite element program ANSYS was used to analyze the temperature field in concrete structures. Then thermal stress field was calculated using the elasticity modulus obtained from code formulate. And the risk of thermal cracking was estimated by the comparison of thermal stress and concrete tensile strength.

Transtympanic Injections of N-acetylcysteine for the Prevention of Cisplatin-induced Ototoxicity

Ototoxicity is a common and irreversible adverse effect of cisplatin treatment with great impact on the patients' quality of life. N-acetylcysteine is a low-molecular-weight agent which has shown substantial otoprotective activity. The role of transtympanic infusions of N-acetylcysteine was examined in a cohort of patients treated with cisplatin-based regimens. Twenty cisplatin-treated patients were subjected, under local anesthesia, to transtympanic N-acetylcysteine (10%) infusions in 1 ear, during the hydration procedure preceding intravenous effusion of cisplatin. The contralateral ear was used as control. The number of transtympanic infusions was respective to the number of administered cycles. Hearing acuity was evaluated before each cycle with pure tone audiometry by an audiologist blinded to the treated ear. A total of 84 transtympanic infusions were performed. In treated ears, no significant changes in auditory thresholds were recorded. In the control ears cisplatin induced a significant decrease of auditory thresholds at the 8000 Hz frequency band (P=0.008). At the same frequency (8000 Hz), the changes in auditory thresholds were significantly larger for the control ears than the treated ones (P=0.005). An acute pain starting shortly after the injection and lasting for a few minutes seemed to be the only significant adverse effect. Transtympanic injections of N-acetylcysteine seem to be a feasible and effective otoprotective strategy for the prevention of cisplatin-induced ototoxicity. Additional studies are required to further clarify the efficiency of this treatment and determine the optimal dosage and protocol.

Interpretation of the Early Hydration Procedure of Standard Cement Materials by Electrodeless Resistivity Method

In this paper, the early hydration procedure of standard cement materials is tested and analysized with electrodeless resistivity method. The experimental results show that for standard cement material, the early hydration procedure can be divided into 4 stages: dissolution period, setting period, acceleration period and deceleration period, respectively. Moreover, the characteristic point according the experimental data can be defined to determined stage in the hydration procedure, and be related with the key parameters for cement materials in hydration procedure, such as water/cement ratio. The electrodeless resistivity method can be used to predict the hydration behavior, especially early hydration behavior of cement as a new measurement technology.

The Study on Preparation of Kaolin-Acrylic Super Absorbent Polymer and its Internal Curing Effect in the Hydration Procedure of Cement Materials

In this paper, a new kind of superabsorbent polymer (SAP) is designed and prepared. Using sodium persulfate as initiator and N,N’-methylene bisacrylamide as Crosslinker, monomer of acrylic acid can be grafted into the skeleton of natural mineral kaolin with the method of microwave irradiation. The performance of water adsorption for SAP is tested in saturated Ca(OH)2 solution. Also, the internal curing effect of SAP to hydration procedure of cement paste is studied. The result shows that the compressive properties and flexural strength of cement paste specimens in early stage have significant improvement in contrast to those without superabsorbent polymer or excessive or a small amount of superabsorbent polymer, when superabsorbent polymer is accounted for 0.3% to 0.5% of the total cement.

Interpretation of the Early Hydration Procedure of Standard Cement Materials by Electrodeless Resistivity Method

In this paper, the early hydration procedure of standard cement materials is tested and analysized with electrodeless resistivity method. The experimental results show that for standard cement material, the early hydration procedure can be divided into 4 stages: dissolution period, setting period, acceleration period and deceleration period, respectively. Moreover, the characteristic point according the experimental data can be defined to determined stage in the hydration procedure, and be related with the key parameters for cement materials in hydration procedure, such as water/cement ratio. The electrodeless resistivity method can be used to predict the hydration behavior, especially early hydration behavior of cement as a new measurement technology.

Measuring and Modeling Analysis of Electrochemical Impedance Spectroscopy for Hydration Procedure of Cement Materials

In this paper, the electrochemical impedance spectroscopy method is applied to characteristic the hydration procedure in cement materials. And a new equivalent circuit model is developed to express the hydration procedure of cement material. As cement paste is a complicated electrochemical system with multi-phase transmission, the equivalent circuit model is considered with the additional double layer capacitance effect at the interface among the hydration products in cement materials. It can express the electrochemical station in cement material, as the multi-phase mass transmission in the cement-based material during the hydration procedure.

A Study of Size, Microscopic Morphology, and Dispersion Mechanism of Structures Generated on Hydration of Proliposomes

Proliposomes were made by coating lactose monohydrate (LMH), sucrose or sorbitol particles with phosphatidylcholine. Proliposomes hydrated under static (i.e., no shaking) conditions instantly generated liposomes which deaggregated immediately using sorbitol carrier and over a period of 5 minutes using LMH or sucrose particles. Manual dispersion of sucrose-based or sorbitol-based proliposomes generated spherical vesicles, while vesicles generated from LMH-based proliposomes were rich in elongated wormlike structures. The effect of formulation on liposome size was minimal. Overall, carrier type and hydration procedure of proliposomes had a marked effect on liposome morphology while formulation had minimal effect on liposome size.

Influence of Stone Dust in Manufactured Sand on Resisting Chloride Penetration in Marine Concretes

In China, manufactured sand has been widely used as fine aggregate in concrete. Therefore, it is necessary to investigate the effect of manufactured sand on durability of concrete. This research studies the influence of stone dust content in manufactured sand on resisting chloride penetration in marine concrete by strength and other physical mechanical tests, XRD, TGA and pore structure analysis. Test results have shown that the chloride diffusion coefficient increased with increasing the stone dust content in manufactured sand when the stone dust content increasing from 3% to 13%. The stone dust in fine aggregate was participated in hydration procedure of cementitious, which will promote the hydration degree of cementitious and increase the chloride binding capacity of hydration product. The influence of stone dust in fine aggregate on chloride diffusion coefficient were the combined effects of concrete pore structure and cementitious hydration products, and the porosity and pore size distribution were the main factors that influence the changes of diffusion coefficient.

Influence of the Preparation Route on the Supramolecular Organization of Lipids in a Vesicular System

A confocal fluorescence microscopy-based assay was used for studying the influence of the preparation route on the supramolecular organization of lipids in a vesicular system. In this work, vesicles composed of cholesterol and CTAB (1/1 mol %) or cholesterol and DOPC (2/8 mol %) and incorporating two membrane dyes were prepared by either a compressed fluid (CF)-based method (DELOS-susp) or a conventional film hydration procedure. They were subsequently immobilized and imaged individually using a confocal fluorescence microscope. Two integrated fluorescence intensities, I(dye1) and I(dye2), were assigned to each tracked vesicle, and their ratio, I(dye1)/I(dye2), was used for quantifying the degree of membrane inhomogeneity between individual vesicles within each sample. A distribution of I(dye1)/I(dye2) values was obtained for all the studied vesicular systems, indicating intrasample heterogeneity. The degree of inhomogeneity (DI) was similar for Chol/DOPC vesicles prepared by both procedures. In contrast, DI was more than double for the hydration method compared to the CF-based method in the case of Chol/CTAB vesicles, which can suffer from lipid demixing during film formation. These findings reveal a more homogeneous vesicle formation path by CFs, which warranted good homogeneity of the vesicular system, independently of the lipid mixture used.

Experimental study on the swelling behaviour of bentonite/claystone mixture

A mixture of the MX80 bentonite and the Callovo-Oxfordian (COx) claystone were investigated by carrying out a series of experiments including determination of the swelling pressure of compacted samples by constant-volume method, pre-swell method, zero-swell method and swell–consolidation method. Distilled water, synthetic water and humidity controlled vapour were employed for hydration. Results show that upon wetting the swelling pressure increases with decreasing suction; however, there are no obvious effects of synthetic water chemistry and hydration procedure on the swelling behaviour in both short and long terms. For the same initial dry density, the swelling pressure decreases with increasing pre-swell strain; whereas there is a well defined logarithmic relation between the swelling pressure and final dry density of the sample regardless of the initial dry densities and the experimental methods. It was also found that swelling pressure depends on the loading-wetting conditions as a consequence of the different microstructure changes occurred in different conditions. Furthermore, it was attempted to elaborate a general relationship between the swelling pressure and the final dry density for various reference bentonites.