Salt Solutions Of Different Concentrations Research Articles

Hybrid super absorbent resin based on waste slag modified zeolite: A potential component adopted to agricultural water retention

The hybrid super absorbent resin (SAR), Poly(acrylicacid-co-acrylamide-co-2-acrylamido-2-methyl-1-propane sulfonic acid) based on zeolite synthesized from solid waste slag (P(AA-co-AM-co-AMPS)/zeolite) was synthesized. The chemical and structural characteristics of the materials were examined through FTIR, XRD, and SEM studies. In the presence of zeolite, the flat surface of the composite transformed into interconnected porous structure. The deionized water equilibrium swelling capacity of the hybridized SAR (835.79 g/g) was higher than that of the pure SAR (524.53 g/g). As much as 40 % of the water was released from the fully swollen hybrid SAR when it was centrifuged. P(AA-co-AM-co-AMPS)/zeolite had a swelling loss rate just of 27.64 % after five swelling/drying cycles. In addition, it still had good absorption in ionic salt solutions of different concentrations and good water retention at different temperatures. This confirmed that the hybridized SAR had excellent water holding capacity and salt solution adsorption. The FTIR and XRD results showed that the excellent performance of the hybridized SAR may originate from the interconnection of the zeolite and the pure SAR. The P(AA-co-AM-co-AMPS)/zeolite may be utilized as an agricultural water retaining agent.

Experimental Investigation on the Effect of Salt Solution on the Soil Freezing Characteristic Curve for Expansive Soils

With the development of the Belt and Road Initiative in China, high-speed railways are booming and inevitably pass through seasonal frost regions. In Nanyang basin, due to seasonal changes, railway subgrades will undergo frost heaving and thawing subsidence. The freezing characteristics of the soil are characterized by the freezing characteristic curve, and the important factors affecting the freezing characteristic curve are the content of expansive clay minerals in the soil and the salt solution. Therefore, three soil samples with different montmorillonite contents were saturated with salt solutions of different concentrations, and the freezing temperature of the soil samples was controlled by a cold bath. After the temperature equilibrium, the frozen stable soil samples were put into a nuclear magnetic resonance instrument to test the unfrozen water content, and the relationship between the freezing temperature and the unfrozen water content of expansive soil under different salt solution concentrations was obtained. Additionally, a unified model was used to simulate the test results. The results show that SFCC shifts to the left, that is, the sodium chloride salt solution reduces the freezing point of the soil sample so that it has more unfrozen water at the same temperature. At the same time, the soil’s freezing characteristic curves are closely related to content of expansive clay minerals in the soil. The more expansive clay mineral content, the greater the corresponding unfrozen water content. These results provide some basic insights for improving the frost heave and thaw subsidence problems of railway subgrades in seasonal permafrost regions, which will have a positive impact on promoting the management and rational application of land resources and the promotion of sustainable development.

Effect of dialysate type on ultrasound-assisted self-assembly Zein nanocomplexes: Fabrication, characterization, and physicochemical stability

This study aims to investigate the effect of the dialysate type on the properties of nanocomplexes. Nanocomplexes of zein-sodium caseinate-curcumin (ZNC) and zein-gum arabic-curcumin (Z-G-C) were prepared by ultrasound-assisted dialysis using salt solutions of different concentrations (Na+ and Ca2+; 2 – 10 mM). With increasing Na+ concentration, the overall particle size of ZNC and Z-G-C decreased first and then increased. The Ca2+ concentration did not affect the particle size of ZNC and Z-G-C, with good storage stability. The encapsulation efficiency of ZNC decreased significantly from 72.3 ± 6.2 % to 59.8 ± 8.6 % with increasing Na+ concentration, while that of Z-G-C increased first and then decreased. The encapsulation efficiency of Ca2+ treated ZNC nanoparticles was higher than that of Na+ induced nanoparticles. Ca2+ did not affect the encapsulation efficiency of Z-G-C nanoparticles. Fluorescence spectroscopy analyses, CD, FTIR, and XRD showed Na + and Ca2+ dialysis modified the secondary structure of ZNC and Z-G-C through adding hydrogen bonding and electrostatic interactions. Na+ and Ca2+ improved the thermal stability of Z-G-C and reduced the thermal stability of ZNC. After encapsulating curcumin, the crystallinity of ZNC and Z-G-C induced by Na+ and Ca2+ decreased to 45.9 % − 63.9 %, and the amorphous area increased. The above results indicated that Ca2+ dialysis could increase the encapsulation efficiency and thermal stability of the nanoparticles, and improve the loading characteristics of zein nanoparticles. The Z-G-C nanoparticles induced by Na+ and Ca2+ showed better thermal and storage stability.

Influence of Composition Parameters, Curing Conditions and Salt Solutions on Geopolymer Concrete Properties.(Dept.C)

The growing demand for environmentally friendly construction has been the driving force behind the production of sustainable and cost-effective construction materials. Portland cement (PC), which is not considered an environmentally friendly material, is an important ingredient in concrete. In contrast to Portland cement, geopolymers are gaining increased interest as low-CO2 emission binders. This research consists of two basic stages, the first stage investigates the effects of many parameters on the properties of geopolymer concrete based on fly ash, in particular the compressive strength, tensile strength, and flexural strength .The parameters included were fly ash content, degree of solution molarity, alkaline liquid ratio to fly ash content, curing conditions, fine aggregate to coarse aggregate ratio. Second stage of the research concerned with the durability of geo-polymer concrete developed using fly ash class-F. As a guide for assessing the durability of geo-polymer concrete, the efficiency of ordinary Portland cement (OPC) concrete is also discussed. The influence of salt solutions of different concentrations through various periods of wetting – drying cycles on the weight loss, water absorption, and geo-polymer concrete has been investigated for its compressive strength. According to the first stage results, the best parameters which gave the highest geo-polymer concrete's mechanical properties, were: fly ash content of 400 kg/m3, 16 M degree of molarity, curing time of 3 days in oven, the ratio of alkaline liquid to the content of fly ash equals 0.5 and ratio of fine aggregate to coarse aggregate equals to 1:2, where the compressive strength reached its highest value (387 Kg/cm2). The results of second stage revealed that geopolymer concrete is less affected than cement concrete with respect to compressive strength and more affected in weight loss and water absorption. Geopolymer concrete showed an increase in water absorption compared to OPC concrete, after 9 weeks of wetting – drying cycles in salt solutions, by about 176% &184% for 5% & 10% solutions concentration, respectively. Also, more weight loss for geopolymer concrete specimens was revealed compared to OPC concrete by about 33% & 30% for 5% & 10% solutions concentration, respectively. However, the geopolymer concrete (GPC) showed less reduction in compressive strength due to the exposure to salt solutions (wet – dry cycles) than OPC. For both solution concentrations (5% & 10%), the average reductions in GPC compressive strength were 18%& 25%, respectively, while the corresponding reductions in OPC were 25% & 34%.

Ag nanoparticle ink coupled with graphene oxide cellulose paper: a flexible and tunable SERS sensing platform.

Surface-enhanced Raman scattering (SERS) is highly promising for ultra-sensitive detection in a series of applications. Although extensive advances have been achieved in SERS technologies, the preparation of highly efficient SERS substrates still suffers from several limitations, including complex preparation procedures, high cost, and instability for long time storage. To address these problems, we report a novel, to the best of our knowledge, SERS platform that combines graphene oxide (GO) and cellulose composite paper with colloidal silver nanoparticle (Ag NP) ink. As an efficient substrate, the GO and cellulose composite paper that features hierarchical micro-nanostructures and improved interaction with target molecules can be fabricated on a large scale, and the Ag NP ink can be well stored, avoiding being oxidized in ambient conditions. In this way, our SERS platform not only reduces the cost, but also improved the stability. The sensitivity, reproducibility, and tunable SERS detection performance were evaluated using rhodamine 6G as probing molecules. To demonstrate the capability of our SERS platform in practical analysis, the SERS spectra of two monosodium salt solutions of different concentrations have been collected. The SERS platform has revealed great potential for practical application of SERS technologies.

ЭФФЕКТЫ СОДЕРЖАНИЯ ПРОИЗВОДИТЕЛЕЙ И МОЛОДИ РЫБ В РАСТВОРАХ ПОВАРЕННОЙ СОЛИ РАЗЛИЧНОЙ КОНЦЕНТРАЦИИ

The aim of the research is to develop new efficient method of fish cultivation in a medium with totally controlled conditions. The main task is the morpho-physiological and piscicultural-biological analysis effects of farming fish- breeders and juvenils in salt solutions of different concentrations. Laboratory and industrial fish contents tests for sea water and salt solutions medium of different salinity have been implemented on the most valuable fish species: russian and stellate sturgeon, rainbow trout, bullhead and roach.The results were evaluated by piscicultural-biological and physiological indicators: content state of hemoglobin, total protein, serum osmolarity, abdominal fluid and urine. Cytomorphometrical analysis of the hypothalamic-hypophysial neurosecreto-ry system (HHNS) status was performed by light and electron microscopy. The enhance effects of fish survival, breeders reproductive quality, youngs growth rates were first established for medi-um with "critical" salinity 4-8‰ For breed-ers originally it was shown the possibility to change sea water on the table salt solution of the same concentration. With such a low concentration of salt a new biostimulating effect of this artificial medium on the fish body was installed, due to the absence of its well-known toxicity. The highest degree of survival and delayed sex maturation of roach and stellate sturgeon were specifically in-stalled for the same concentration of indus-trial salt solutions. The best physiological body state was also shown in this solution (5‰) by physiological and biochemical analysis, regarding minimal losses in hemo-globin and serum protein. Histophysiological analysis of the sevruga HHNS state showed the smallest degree of activity in this solu-tion to the end of the experience, proportion-ate to the severity of stress. Such moderately active HHNS in solution of salt 5‰ clearly indicates the status of the eustress and high HHNS activity for control groups indicates the typical status of the stress. By electron microscopy study HHNS state sevruga and sturgeon in hypertonic salt solutions of dif-ferent concentrations it was shown, that at 17 and 22‰ they were under stress and at 32‰ represented irreversible disstress. All 3 in-stalled stress status depends on the intensity and duration of exposure. Their effects are alternative and therefore are managed, trans-forming from bio-stimulation in reversable stress and, after reaching the limits of physi-ological species cause toxic effect and then a state of disstress and death. The possibility of changing the sea water to industrial salt solution 5-7‰, allowed to develop "A meth-od to reserve fish breeders", which ,however, can not be applied for the young fish breed-ing. So the next stage in the development of this method was to test it already on juvenile and young fish, in order to determine its effective cultivation in this artificial biostim-ulating medium. The results of the search experience on trout fingerlings showed the increased survival and growth in salt solu-tions, especially in 12‰ as compared to con-trol. The first experimental verification of this method on the clarias bullhead finger-lings in the recycling aquacultural system (RAS) showed the largest growth rates in 5‰ salt solution, and its total survival in all variants. Received data and analysis of biostimu-lated effects impact on the body's critical salinity gives the opportunity to develop a fundamentally new way of cultivation of valuable fish species in an artificial biostim-ulated habitat. This technique can allow to manage breeding - obtaining offspring and the cultivation of young fish. It is aimed at improving the efficiency of breeding fish in aquaculture due to the availability of the application for any type of fish farms with the effects of increasing survival rate and young growth rate. It is expected that the change of the sea water with the cheap solu-tion of table salt can be widely practiced at fish plants in various fields and at all stages of fish biotechnology works, especially RAS.

Swelling pressure of Na- and Ca-montmorillonites in saline environments: A molecular dynamics study

The swelling pressure of bentonite clay is an important characteristic that influences its use in nuclear waste disposal repositories. A molecular dynamics study was performed to investigate the influence of salt solutions of different concentrations on the swelling pressure of Na-montmorillonite and Ca-montmorillonite in NaCl and CaCl2 solutions, respectively. Na-montmorillonite shows a gradual increase in swelling pressure as the dry density increases, while Ca-montmorillonite shows a slow increase as the dry density increases, after which a steeper increase in swelling pressure was observed. There is an overall decrease in swelling pressure of Na- and Ca-montmorillonites as the salinity of the surrounding solution increases. The influence of ionic strength was most prominent for Na-montmorillonite at moderate to high dry densities. At low to moderate dry densities, the swelling pressure of Na-montmorillonite was greater than that of Ca-montmorillonite; however, at high dry densities and ionic strengths, Ca-montmorillonite exhibits the higher swelling pressures.

2D materials as an emerging platform for nanopore-based power generation

Osmotic power generation, the extraction of power from mixing salt solutions of different concentrations, can provide an efficient power source for both nanoscale and industrial-level applications. Power is generated using ion-selective channels or pores of nanometric dimensions in synthetic membrane materials. 2D materials such as graphene and MoS2 provide energy extraction efficiencies that are several orders of magnitude higher than those of more established bulky membranes. In this Review, we survey the current state of the art in power generation with both 2D materials and solid-state devices. We discuss the current understanding of the processes underlying power generation in boron nitride nanotubes and 2D materials, as well as the available fabrication methods and their impact on power generation. Finally, we overview future directions of research, which include increasing efficiency, upscaling single pores to porous membranes and solving other issues related to the potential practical application of 2D materials for osmotic power generation. Synthetic nanopores in 2D materials are an emerging platform for power harvesting from the controlled mixing of fresh and salty water. This Review surveys their physics and materials properties and the progress in the design of new, high-density, ion-selective membrane materials.

Role of Salt Migration in Destabilization of Intra Permafrost Hydrates in the Arctic Shelf: Experimental Modeling

Destabilization of intrapermafrost gas hydrate is one possible reason for methane emission on the Arctic shelf. The formation of these intrapermafrost gas hydrates could occur almost simultaneously with the permafrost sediments due to the occurrence of a hydrate stability zone after sea regression and the subsequent deep cooling and freezing of sediments. The top of the gas hydrate stability zone could exist not only at depths of 200–250 m, but also higher due to local pressure increase in gas-saturated horizons during freezing. Formed at a shallow depth, intrapermafrost gas hydrates could later be preserved and transform into a metastable (relict) state. Under the conditions of submarine permafrost degradation, exactly relict hydrates located above the modern gas hydrate stability zone will, first of all, be involved in the decomposition process caused by negative temperature rising, permafrost thawing, and sediment salinity increasing. That’s why special experiments were conducted on the interaction of frozen sandy sediments containing relict methane hydrates with salt solutions of different concentrations at negative temperatures to assess the conditions of intrapermafrost gas hydrates dissociation. Experiments showed that the migration of salts into frozen hydrate-containing sediments activates the decomposition of pore gas hydrates and increase the methane emission. These results allowed for an understanding of the mechanism of massive methane release from bottom sediments of the East Siberian Arctic shelf.

Numerical simulation of renewable power generation using reverse electrodialysis

We numerically investigate renewable power generation using reverse electrodialysis (RED), by harnessing salinity gradient energy of two constant inflows of salt solutions of different concentrations via a charged nanochannel. We compute and elucidate coupled flow, ion flux, electrical potential, and resultant electric outputs in the nanofluidic RED battery. The results of power output density and ion transfer across the nanochannel strongly depend on nanochannel height, whereas open-circuit voltage, short circuit current, and nanochannel resistance on the length. Energy conversion efficiency, on the other hand, display a non-linear dependence on both dimensions. More importantly, the results of nanochannel resistance and power output density reveal a power-law dependence on the concentration difference, quantitatively shedding light on the optimal RED flow designs. For the first time, our simulations at different inflow velocities show that the output power and conversion efficiency remain nearly constant at low speed but increase by ≈2.3 times and 10%, respectively, at high rate when advection effect becomes significant comparing to diffusion. These results quantitatively show profound effects of nanochannel dimensions, concentration difference, and inflow velocity on the renewable electrical energy outputs, offering optimal designs for maximizing reverse electrodialysis power.

An Adsorption Reverse Electrodialysis system for the generation of electricity from low-grade heat

A novel process is presented to generate electricity from low-grade heat by combining a Reverse Electrodialysis membrane with an Adsorption desalinator in a closed-loop system. A Reverse Electrodialysis membrane generates electricity by controlled mixing of two salt solutions of different concentrations. An Adsorption desalinator restores the initial salt gradient by utilising low-grade heat for the separation. In this study the process is designed from optimising the salt and material selection to the development of the real system application. Energy and exergy efficiencies of the proposed system show the potential of this novel renewable energy technology. The efficiencies of 227 salts with a range of different valences and 10 adsorption materials have been investigated over a large number of system parameters. The results show that the optimised system can achieve an exergy efficiency of up to 30%. Moreover, high salt concentrations do not significantly increase the specific energy consumption of the Adsorption desalinator, which allows operating the Reverse Electrodialysis membrane at the optimal salt concentrations.

Induced-Charge Enhancement of the Diffusion Potential in Membranes with Polarizable Nanopores.

When a charged membrane separates two salt solutions of different concentrations, a potential difference appears due to interfacial Donnan equilibrium and the diffusion junction. Here, we report a new mechanism for the generation of a membrane potential in polarizable conductive membranes via an induced surface charge. Itresults from an electric field generated by the diffusion of ions with different mobilities. For uncharged membranes, this effect strongly enhances the diffusion potential and makes it highly sensitive to the ion mobilities ratio, electrolyte concentration, and pore size. Theoretical predictions on the basis of the space-charge model extended to polarizable nanopores fully agree with experimental measurements in KCl and NaCl aqueous solutions.

Swelling induced structural changes of a heterogeneous cation-exchange membrane analyzed by micro-computed tomography

3D reconstruction of heterogeneous ion-exchange membranes when swollen in an appropriate electrolyte by micro-computed tomography (μ-CT) can provide important information on structural changes caused by their swelling or shrinkage and used this knowledge along with their electrochemical characteristics for optimization of the structure of these industrially important polymeric composites. We developed a methodology that allows scanning of swollen membrane samples while not being immersed in the solution, a condition necessary for μ-CT analysis of polymeric samples. Qualitative description of membrane swelling and shrinkage induced by volume-changing ion-exchange resin particles demonstrates their strong effect on structural changes in the membrane and identifies salt concentration as one of the major factors affecting the extent to which the membrane swells or shrinks. Experimental study focused on investigating the effect of salt concentration reveals that membrane volume decreases with increasing salt concentration. The dependence between the volume of the membrane and the concentration was well fitted with a natural logarithm. This fit can be used as an empirical equation for estimating the volumetric changes of the membrane caused by immersion in salt solutions of different concentrations.

Development of Cost-Effective Ion-Exchange Membranes for High Performance Reverse Electrodialysis

Reverse electrodialysis (RED) is one of the promising processes for generating electricity from the salt concentration gradient between river and sea water. A RED stack contains alternately arranged anion- and cation-exchange membranes (AEMs and CEMs, respectively) which separate salt solutions of different concentrations. The power generation performance of REDs significantly depends on the characteristics of ion-exchange membranes (IEMs). The important membrane properties dominating the power generation in RED processes are the ion-exchange capacity, water swelling degree, electrical resistance, permselectivity, membrane thickness, and surface morphology etc. Moreover, the cost-effectiveness of IEMs is the most significant factor determining the successful commercialization of the RED process. In recent years, pore-filled IEMs (PFIEMs) in which an inert porous substrate provides excellent mechanical and chemical stabilities while a filling ionomer selectively transports ions through the membrane have been receiving great interests in the application to various energy conversion processes such as fuel cells and redox flow batteries. Simple and cheap mass production by a roll-to-roll process is one of the main advantages of the PFIEMs. In this work, we have investigated the optimum design parameters of the PFIEMs for successful application to a RED process. In addition, we have studied on the surface modification of the PFIEMs through facile methods for the improvement of the membrane properties. (This work was supported in part by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korea government (MSIP) (2015R1A1A1A05001486) and the Technology Innovation Program funded by the Korea government (MOTIE) (No. 10047796).)

The Effects of Hydrophobic Coatings on an Insulative Skirt Layer to Decouple Galvanic Corrosion Between Mechanically-Coupled Aluminum Alloy and Carbon-Fiber Reinforced Polymer-Matrix Composites

Lightweight metals such as aluminum (Al) are being frequently coupled to polymer-matrix composites (PMCs) to reduce weight and improve performance in a multitude of applications in the defense, aerospace, automotive and civil-infrastructure industries. The intimate contact of carbon-fiber reinforced (CFR) PMCs with Al alloys can result in galvanic corrosion of the Al alloys. The electrically conductive carbon fibers in the CFR PMCs serve as cathodes and induce galvanic corrosion of the Al. The galvanic corrosion between 6061-T6 Al and CFR PMC can be effectively attenuated by decoupling Al from CFR PMC using an insulating skirt layer. The deposition of salts on the insulative skirt, however, can create a continuous ionically-conductive electrolyte film that can bridge the CFR PMC and Al, thus reducing the effectiveness of the skirt. The utilization of hydrophobic coatings on the skirt can help to attenuate galvanic corrosion by breaking up the continuous electrolyte film. In this study, the effect of hydrophobic coatings on insulative skirt materials was investigated to attenuate galvanic corrosion between mechanically coupled 6061-T6 Al and CFR PMC. Experiments were conducted in accelerated laboratory and outdoor conditions. The galvanic corrosion rates were monitored for coatings of different degrees of hydrophobicity, various skirt lengths, and exposure conditions and. Initially, the galvanic corrosion rates for couples with different insulating-skirt lengths coated with a silane-based ceramer (i.e., Siloxel) were monitored in a humidity chamber at 30o C and 90% RH over a period of up to 3 days using the zero resistance ammeter (ZRA) technique. The couples were sprayed with salt solutions of different concentrations. Results from this accelerated humidity ZRA experiment showed that a skirt length of only 0.5 inch was very effective in attenuating galvanic corrosion. To study the effectiveness of different coatings, specimens were fabricated with a 0.5-inch long skirt and coated with either Siloxel, epoxy, polyurethane or latex. The resulting galvanic corrosion rates were then compared. The two best coatings in attenuating galvanic corrosion (i.e., Siloxel and polyurethane) were selected for outdoor exposure. CFR PMC/Al galvanic couples with 0.5 inch insulating skirts (with either the Siloxel or polyurethane coatings, or no coatings) were exposed at rain forest (Manoa) and severe marine (MCBH) environments for 2 months. The CFR PMC/Al galvanic specimens at the severe marine site were exposed in two conditions: sheltered and unsheltered. The sheltered specimens were subjected to significant salt build up; whereas, the unsheltered specimens were subjected to cleansing effects of rain. The effect the salt deposition characteristics on galvanic corrosion between the sheltered and the unsheltered conditions was studied.

Effect of ambient carbon dioxide on salt permeability and sorption measurements in ion-exchange membranes

Characterizing ion sorption and transport properties in charged polymers is critical for developing fundamental understanding necessary to prepare high performance membranes. The presence of dissolved CO2 from the atmosphere in aqueous solutions can interfere with measurements of salt permeability and sorption in ion-exchange membranes, frustrating characterization of ion transport properties. In water or aqueous saline solutions, CO2 speciates to form ions such as H+ and HCO3−. NaCl or other salt permeability experiments are often performed by exposing a membrane to two salt solutions of different concentrations in a conventional diffusion cell and monitoring the conductivity rise with time in the receiving chamber (i.e., the chamber containing the lower salt concentration). H+ and HCO3− ions in the external solutions on either side of the membrane undergo ion exchange with counter-ions in cation- and anion-exchange membranes, respectively. This CO2-induced ion exchange interferes with conductivity measurements designed to measure receiver salt concentration change with time due to ion permeation through the polymer from the higher salt concentration chamber (i.e., the donor chamber). This phenomenon results in non-linear changes in downstream conductivity with time, which is most pronounced at low donor cell NaCl concentrations, especially for anion-exchange membranes. Furthermore, this effect is absent when an anion-exchange membrane in the HCO3− form is tested using NaHCO3 rather than NaCl for permeability measurements. The effect of CO2 on NaCl permeability measurements can be significantly reduced when ultra-high purity N2 gas is bubbled through the donor and receiver solutions in the diffusion cell during the experiment, making it possible to obtain true NaCl permeability values. During NaCl sorption experiments, when an ion-exchange membrane was equilibrated with a NaCl solution of 0.1M or lower, the amount of desorbed mobile counter-ions was significantly greater than the amount of desorbed mobile co-ions. The desorption of unequal amounts of ions can also be attributed to ion exchange between the membrane and solution phase and has implications for determining the mobile NaCl sorption coefficient. Procedures for addressing these issues are described.

Oral mucosal immunization using glucomannosylated bilosomes.

The present study embarks on the feasibility of GM-bilosomes as a rationally designed vehicle for oral mucosal immunization. Bilosomes containing BSA as a model antigen were found to have vesicle size of 157 +/- 3 nm, PDI of 0.287 +/- 0.045, zeta potential of -21.8 +/- 2.01 mV and entrapment efficiency of 71.3 +/- 4.3%. Bilosomal formulations were freeze dried and entrapped BSA in freeze dried formulations was found to retain its structural and conformational stability as evident by SDS-PAGE and CD analysis. The GM-bilosomes were also found stable in different simulated biological fluids and bile salt solutions of different concentrations. In-vitro drug release revealed that GM-bilosomes were able to sustain drug release up to 24 h. In-vitro cell uptake in RAW 264.7 macrophage cells demonstrated significantly higher uptake of GM-bilosomes in comparison with bilosomes and free antigen. Intestinal uptake studies on excised rat intestinal sections further demonstrated higher uptake of vesicular systems throughout the intestinal region in comparison with free antigen. Significantly higher (p < 0.05) systemic immune response (serum IgG level) was observed in case of GM-bilosomes in comparison with bilosomes and alum adsorbed BSA (BSA-AL) following oral administration. The immune response observed in case of GM-bilosomes was comparable to BSA-AL administered through im route without any significant difference (p > 0.05). More importantly, GM-bilosomes were found capable of inducing mucosal immune response as well as cell mediated immune response which was not induced by im BSA-AL. In conclusion, GM-bilosomes could be considered as promising carrier and adjuvant system for oral mucosal immunization and productively exploited for oral delivery of other candidate antigens.

Force Interactions of Nonagglomerating Polylactide Particles Obtained through Covalent Surface Grafting with Hydrophilic Polymers

Nonagglomerating polylactide (PLA) particles with various interaction forces were designed by covalent photografting. PLA particles were surface grafted with hydrophilic poly(acrylic acid) (PAA) or poly(acrylamide) (PAAm), and force interactions were determined using colloidal probe atomic force microscopy. Long-range repulsive interactions were detected in the hydrophilic/hydrophilic systems and in the hydrophobic/hydrophilic PLA/PLA-g-PAAm system. In contrast, attractive interactions were observed in the hydrophobic PLA/PLA and in the hydrophobic/hydrophilic PLA/PLA-g-PAA systems. AFM was also used in the tapping mode to determine the surface roughness of both neat and surface-grafted PLA film substrates. The imaging was performed in the dry state as well as in salt solutions of different concentrations. Differences in surface roughness were identified as conformational changes induced by the altered Debye screening length. To understand the origin of the repulsive force, the AFM force profiles were compared to the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory and the Alexander de Gennes (AdG) model. The steric repulsion provided by the different grafted hydrophilic polymers is a useful tool to inhibit agglomeration of polymeric particles. This is a key aspect in many applications of polymer particles, for example in drug delivery.

Comparison between fresh and exposed swelling elastomer

Last decade has seen growing use of swelling elastomers in various applications by the oil and gas industry. Elastomers with special properties have been developed to sustain the specific downhole conditions of temperature, pressure, and chemical environment in different wells. Apart from targeted short-term tests conducted by rubber developers and drilling application companies, little is known about material characterization of such elastomers. Even these test results are not generally available in the public domain due to proprietary rights. In particular, an important factor that has not been previously explored is the effect of exposure on material response of swelling elastomers. Zonal isolation packers and other forms of elastomer-mounted tubulars are often stacked in open yards for a long time before their deployment in wells. Properties of elastomers may significantly change due to their exposure to air, sunlight, and humidity. Some results from a comparative study of the behavior of fresh and exposed samples of an ethylene propylene diene monomer (EPDM)-type water-swelling elastomers are reported here. Methodology of the swelling test was developed in consultation with petroleum engineers and rubber manufacturers. Other experiments were designed and performed in line with standard ASTM test methods. Properties of elastomers that are investigated are hardness, compression set, tensile set, tensile properties, and swelling behavior. Elastomer samples were allowed to swell for a total test duration of 1000 h. Two specimen geometries were tested for swelling: unconfined disc samples to study the behavior of free elastomer and plate samples (elastomer vulcanized on steel plate) to emulate the actual seal performance. Swelling was carried out in salt solutions of different concentrations and at different temperatures. Hardness of exposed elastomer samples (EPDM1) was generally higher than that of fresh samples (EPDM2). Similarly, exposed elastomer showed significantly higher amount of compression set when compared with fresh elastomer. Short-duration tensile set values (10 min test) were almost the same for both sample types. However, tensile set results for the longer-duration tests (10 h and 20 h) were higher for exposed samples. Surprisingly, stress–strain graphs for both fresh and exposed elastomers were almost linear, while rubber-type materials typically show a highly nonlinear behavior. Values of modulus of elasticity and stress at fracture were considerably higher for exposed samples. In contrast, percentage elongation results were higher for fresh samples. Amount of swelling against swelling time showed an up-and-down trend for both the sample types. At the same temperature and under brine solution of the same concentration, fresh elastomer generally swelled far more than the exposed one. The overall observation from the variety of experimental results is that exposure to sun and moisture for extended periods of time reduces the flexibility and swelling capacity of these elastomers.

Inductance-based sensing technique for wireless, remote-query measurement in liquid media

A novel inductance-based sensing technique is presented for remote query measurement in different liquid media including organic solvents and inorganic solutions. The inorganic solutions tested included salt solutions of different concentrations, and the organic solvents detected included 1,4-dioxane and tetrahydrofuran. To extend the application of the sensor, bacterial culture media were also detected, and the growth of Escherichia coli (E. coli) was controlled. The influential factors which may affect the inductance responses were studied in detail. It was found that quantitative relationships exist between the sensor’s inductance response and the physico-chemical parameters of the liquid media. The sensor’s inductance response (L) decreases with the increase of salt concentration (C) and its ionic valence (e) according to a semi-logarithmic equation LgL = aeC + b, where a and b are constants, which is in accordance with the theoretically deduced equation. The inductance variation rate (K)