Salt Crystal Size Research Articles

Formation-water evaporation and salt precipitation mechanism in porous media under movable water conditions in underground gas storage

Underground gas storage (UGS) plays an important role in large-scale energy (natural gas) storage, while salt deposition may affect the storage and production capacity of UGS. However, salt precipitation mechanism of UGS under movable water conditions is not clear. This work aims at understanding salt precipitation on rock properties of an UGS in porous media under movable water conditions. Firstly, core flooding experiments are performed to establish the relationship between dynamic petrophysical properties and the amount of salt crystals. The dynamic process of salt precipitation at the pore-scale is further captured by microscopic visualization experiments, and the location and morphology of salt crystals at micro-scale are also observed using scan electron microscope (SEM). Results indicate that formation-water evaporation and salt precipitation improve the formation properties when the amount of deposited salt is less than 39 mg/g. After the amount of deposited salt is more than 48 mg/g, formation porosity and permeability can be reduced. The size of salt crystals under movable water (>40 μm) is much larger than that under irreducible water conditions (1 μm–5 μm). This work offers a methodology for analyzing the effect of salt precipitation on the UGS in porous media under movable water conditions.

Effect of interface-active proteins on the salt crystal size in waterborne hybrid materials

Aqueous processes yielding hybrid or composite materials are widespread in natural environments and their control is fundamental for a multiplicity of living organisms. Their design and in vitro engineering require knowledge about the spatiotemporal evolution of the interactions between the involved liquid and solid phases and, especially, the interphases governing the development of adhesion during solidification. The present study illustrates the effects of distinct proteins on the precipitation of sodium chloride encompassing the size, shape and distribution of halite crystals formed during the drying of droplets containing equally concentrated saline protein solutions. The precipitates obtained from aqueous sodium chloride formulations buffered with tris(hydroxymethyl)aminomethane (Tris) contained either bovine serum albumin (BSA), fibrinogen or collagen and were characterized with respect to their structure and composition using optical and electron microscopy as well as x-ray analysis. The acquired findings highlight that depending on the protein type present during droplet drying the halite deposits predominantly exhibit cubic or polycrystalline dendritic structures. Based on the phenomenological findings, it is suggested that the formation of the interphase between the growing salt phase and the highly viscous saline aqueous jelly phase containing protein governs not only the material transport in the liquid but also the material exchange between the solid and liquid phases.

Synthesis and antimicrobial properties of CaCO3-nAg and nAg-CaCO3 nanocomposites

The nanocomposites of nAg-CaCO3 and CaCO3-nAg with different mass content of silver nanoparticles were obtained in a two-stage continuous microwave process. The nanocomposites were characterized by XRD, TEM, UV–vis, and FTIR spectroscopy. The effects of microwave radiation, silver nanoparticles content in the composite and the molar ratio of tannic acid to silver on the size of salt crystallites were studied. The effectiveness of combining silver nanoparticles with CaCO3 was confirmed to exceed 99%. Depending on the input parameters applied, the size of salt crystals in nAg/CaCO3 nanocomposites ranged from 25 to 45 nm, while the size of salt crystals in CaCO3/nAg nanocomposites ranged from 26 to 41 nm. In addition, some of the compositions were tested for their antimicrobial activity on selected yeast and bacterial microorganisms. The prepared materials present a biocidal effect, which makes them suitable for use in antimicrobial preparations.

Study on salt precipitation induced by formation brine flow and its effect on a high-salinity tight gas reservoir

For the tight gas reservoir with high salinity formation water, the flow of formation brine may cause salt precipitation and thus promote scale formation. Salt deposition and the accompanying scale formation as well as swelling and shrinkage of clay minerals may cause blockage of the pore and throats, which will significantly reduce permeability and the subsequent gas production rate. In this study, the influence of salt precipitation/dissolution on the physical properties of a tight gas reservoir is studied. Core analyses, core flooding tests, core evaporation tests, and microscopic visual flooding inspections are carried out on core samples extracted from the Shahejie Formation. To simulate the depletion production process in the subsurface, brine flow characteristics are studied by core flooding tests with pressure reduction at a formation temperature of 115 °C and with the change of pressure ranging from 30 to 1 MPa. The potential changes in physical properties including permeability, porosity, pore radius, pore size distribution, and surface area are analyzed by core evaporation tests. To show the brine flow and geometry of salt deposits in the pore structure, visual brine flooding is observed under high magnification microscope. Photos of the pore structure at different stages of salt precipitation are recorded. The results reveal that salt dissolution/precipitation has a significant impact on flow-through characteristics, and it can be divided into three stages during the depletion process. The damage of salt to the core permeability could reach more than 90%, and it increases gradually with the reduction of porosity and initial permeability and the increase of specific area. The maximum formation damage caused by salt precipitation is realized when the salt crystal size and pore throat diameter are close in size. The semi-empirical Carman-Kozeny equation together with porosity and grain diameter is used to estimate the permeability after precipitation.

ALTERNATIVE METHODS OF TECHNOLOGICAL PROCESSING TO REDUCE SALT IN MEAT PRODUCTS

The world trends in table salt reduction in meat products contemplate the use of different methods for preservation of taste and consistency in finished products as well as shelf life prolongation. There are several approaches to a sodium chloride reduction in meat products. The paper presents a review of the foreign studies that give evidence of the possibility to maintain quality of traditional meat products produced with the reduced salt content. The studies in the field of salty taste perception established that a decrease in a salt crystal size to 20 µm enabled reducing an amount of added table salt due to an increase in the salty taste intensity in food products. Investigation of the compatibility of different taste directions is also interesting as one of the approaches to a sodium chloride reduction in food products. The use of water-in-oil-in-water (w/o/w) double emulsions allows controlling a release of encapsulated ingredients (salt), which enables enhancement of salty taste. The other alternative method of technological processing of meat raw material for reducing salt in meat products is the use of high pressure processing. This method has several advantages and allows not only an increase in the salty taste intensity, but also formation of a stable emulsion, an increase in water binding capacity of minced meat and extension of shelf-life.

Impact of Salt Crystal Size on in‐Mouth Delivery of Sodium and Saltiness Perception from Snack Foods

AbstractFried, sliced potato crisps were flavored with sodium chloride of varying size fractions to investigate the impact of salt crystal size on the delivery rate of sodium to the tongue and resultant saltiness, measured over 65 s with a defined chew protocol (three chews, then holding the bolus in the mouth without swallowing). Salt crystal size impacted upon the delivery rate and perceived saltiness. The smallest crystal size fraction dissolved and diffused throughout the mouth to the tongue saliva faster than the medium and the largest ones; the smallest crystal size fraction also had the highest maximum concentration and greatest total sodium. These results correlated well with the sensory perceived saltiness, where the smallest crystal size fraction resulted in the fastest Tmax, highest maximum saltiness intensity and maximum total saltiness. The different delivery rates can be explained by differential dissolution kinetics and enhanced mass transfer of sodium across the saliva.Practical ApplicationsSodium reduction is a major challenge for the global food industry. The results of this work illustrate how modification of salt crystal size fraction might impact sensory perceived saltiness, and that a smaller crystal size fraction can achieve a greater maximum saltiness per unit of sodium consumed. There are a number of technical hurdles to be overcome before implementation of this approach, both practical (limitations in processability) and sensorial (changes in the time–intensity profile), but the results do demonstrate that enhanced dissolution and diffusion kinetics can be achieved through modification of salt crystal size, which should be seriously considered by snack food manufacturers when approaching product reformulation.

Fabrication of a porous wall and higher interconnectivity scaffold comprising gelatin/chitosan via combination of salt-leaching and lyophilization methods

A novel gelatin/chitosan scaffold with higher porosity and interconnectivity was designed through salt-leaching/lyophilization (SLL) method. The properties of the fabricated scaffolds were compared with conventional scaffolds, which are obtained by thermally induced phase-separation (TIPS) method. The scaffolds made by phase-separation method have high tensile strength, but suffer from less channel interconnectivity, pore uniformity and also low surface porosity. The microstructure, porosity, phosphate-buffered saline (PBS) solution absorption and tensile strength of the prepared scaffolds by SLL method were studied. In this work, SLL as a two-step technique is introduced for creating porosity to improve both channel interconnectivity and pore uniformity for water-soluble polymers in comparison with the TIPS method. The SLL technique includes two mechanisms: the first, leaching of mixed sodium chloride crystals and particles created during recrystallization of the dissolved NaCl and the second, phase separation during lyophilization at the pore walls. These two steps in porosity formation lead to special pore morphology, which is more suitable for cell culturing because of higher interconnectivity and rich surface porosity in comparison with the phase-separated scaffolds. The prepared scaffolds, using this technique with different salt/polymer ratios and salt crystal size, have 91–97% porosity and 94–190 μm mean pore size with tensile strength of 72–215 kPa and PBS solution absorption between 12.4 and 19 times dry weight. The pore size of scaffolds prepared using the SLL method could be adjusted independently of polymer solution concentration. These scaffolds have a great potential in skin tissue engineering application.

Modification of Thai Silk Fibroin Scaffolds by Gelatin Conjugation for Tissue Engineering

Silk has been used commercially as biomedical sutures for decades. Recently silk fibroin, especially from Bombyx mori silkworm, has been explored for many tissue engineering applications such as bone and cartilage due to its impressive biological compatibility and mechanical properties. In Thailand, Thai native silkworms have been long cultivated. Distinct characteristics of cocoon Thai silk are its yellow color and coarse filament. There is more sericin in Thai silk than in other Bombyx mori silks. These characteristics provide Thai silk a unique texture for textile industry. It is therefore the aim of this study to develop three-dimensional silk fibroin-based scaffolds from Thai yellow cocoon “Nangnoi-Srisaket” of Bombyx mori silkworms using salt-leaching method. To enhance the biological properties, type A gelatin, the denature form of collagen having good biocompactibility, was used to conjugate with silk fibroin scaffolds. The pore size of salt-leached silk fibroin scaffold structure represented the size of salt crystals used (600-710µm). After gelatin conjugation, gelatin was partly formed fibers inside the pores of silk fibroin scaffolds resulting in fiber-like structure with highly interconnection. Gelatin conjugation enhanced the compressive modulus of silk fibroin scaffolds by 93%. The results on in vitro culture using mouse osteoblast-like cells (MC3T3-E1) showed that gelatin conjugation could promote the cell proliferation in silk fibroin scaffolds. Moreover, the observed morphology of cells proliferated inside the scaffold after 14 days of culture showed the larger spreading area of cells on conjugated gelatin/silk fibroin scaffolds, compared to round-shaped cells on silk fibroin scaffolds. The results implied that Thai silk fibroin looked promising to be applied in tissue engineering and gelatin conjugation on Thai silk fibroin scaffolds could enhance the biological properties of scaffolds.

Bond strengths of the lost salt procedure: A new retention method for resin-bonded fixed prostheses

Shear bond tests were described for a new lost salt procedure for developing retention to the metal framework for a resin-bonded fixed partial denture. It was found that different salt crystal sizes influence the bond strength. The salt crystal size range of 150 μm to 250 μm was significantly stronger than the smaller and larger size ranges tested. This size range produced a surface more easily evaluated visually than an etched metal surface for retention. The bond failure observed was a fracture of the bonding resin and not an adhesive pulling our of the resin from the cubic surface voids.