Solutions Of Various Concentrations Research Articles

Performance investigation on electrodialysis regeneration of potassium formate desiccant solution for liquid desiccant air-conditioning systems

In this work, the ED regeneration experiments were conducted using KCOOH (potassium formate) liquid desiccant, which is attracting attention due to its non-corrosiveness and low toxicity. Varying solution concentration, solution temperature, and current density, effect of the operating conditions on overall transport number, overall hydration number, overall osmotic coefficient, and area-specific resistance (ASR) was analyzed. In particular, effect of the solution temperature on the ASR, which was frequently ignored in previous research, was evaluated. As the solution temperature increased from 21 °C to 30 °C, the ASR decreased 21% and 17% at different concentration conditions. Additionally, the overall transport number of the KCOOH was compared with experimental data of different liquid desiccants in other research. The result showed that at low solution vapor pressure condition, KCOOH recorded the largest overall transport number so that it has a potential to be an energy-efficient working fluid for ED regeneration system. Furthermore, the analysis results and the regression equations can be utilized in developing a system modelling of the liquid desiccant regeneration using ED with KCOOH desiccant in future research.

Diffusiophoresis in a Taylor-dispersing solute

The motion of particles in a channel containing solute is, in part, a result of diffusiophoresis. Previous studies of diffusiophoresis in narrow channels have focused on quasi-one-dimensional dynamics. We consider the two-dimensional dynamics in an early-time regime. In this regime, spanwise variations in solute concentration have not yet diminished, and cross-channel particle migration may be significant.

The kinetics of dissolution and cluster formation of fullerene in polar and low polar solutions

Fullerene and fullerene like nanostructures play a main role in various research areas. Theamount of investigations of fullerene C60 and C70 has grown up considerably due to their several unique properties [1-2, 6]. In this report we present theoretical models for cluster growth, the modeling of small angle neutron scattering curves, and the results of structural analysis (SANS) for polar solutions of these macromolecules. Investigation of kinetics of dissolution and complex formation are studied for C60/Benzene, C60/Toluene and C60/Nmethyl-2-pyrrolidone (NMP) solutions of various concentrations by UV-Vis spectrometry. We model the kinetics of simultaneously occurring processes in the solution via a system of basic kinetic equations and obtain the corresponding parameters dependence on preparation conditions. The investigation of structural properties of fullerene solution in CS2 was performed at the YuMO instrument of the IBR-2 reactor. The results are compared tomolecular dynamics simulations, and other research works

Unraveling the binding microprocess of individual Streptococcus mutans cells via sucrose-dependent adhesion based on surface plasmon resonance imaging

ABSTRACT The initial microprocess of a major cariogenic bacterium Streptococcus mutans forming biofilm at a single-cell level via sucrose-dependent adhesion has not been observed because the cells’ high moisture content caused measurement challenges. To develop a high-sensitivity biosensor chip and a real-time, label-free method to observe bioactive molecule interactions with single cells from oral biofilms. We made the chips of immobilized bacteria by micronano-processing. A surface plasmon resonance imaging (SPRI) system was used to detect and record the association and dissociation microprocess of S. mutans with sucrose/dextran solutions of various concentrations, and the calculus model was adopted to treat the data. At the location of S. mutans, a unique ‘comet-tail’ SPRI signal was observed. The binding patterns of S. mutans differed between individual cells exposed to the same solution as well as between sucrose and dextran. The different cells exhibited different affinities with dissociation constants for sucrose being 5.697 × 10−3 to 3.689 M and for dextran 1.235 × 10−3 to 1.282 M, indicating cell-to-cell heterogeneity. Our SPRI detection method is effective in investigating microbial binding, initial biofilm formation, and oral microecology. It offers new possibilities for studying oral microorganism characteristics and development of oral diseases.

Analytical Modeling of Solute Transport in a Two-Zoned Porous Medium Flow

The objective of this study is to model the transport of groundwater contamination in one-layered and two-zoned porous medium flows by an analytical approach. The one-dimensional advection–dispersion equation (ADE) has usually been used to describe the problems of pollutant transport in a water environment. This study presents some exact solutions to the one-dimensional ADE to examine the variation of solute concentration with and without the biodegradable effect in an unconfined aquifer of a finite domain by the generalized integral transform method (GITM). The modeling results for the concentration of groundwater contamination show that the pollutant concentration is more sensitive to the Peclect number than to the retardation factor and the first-order decaying coefficient in uniform groundwater flow. In composite soil zones, decaying and diffusion factors have significant effects on the contamination concentration around the interface, especially over a long-term period. The transport flux between the two regions is determined by the concentration gradient at the interface of the two regions. The contaminated concentration decreases as the retardation factor, Peclect number, and the first-order decaying coefficient increase for every location at a fixed duration. Moreover, the contaminated concentration is more sensitive to the Peclect number than to the retardation factor and the first-order decaying coefficient in uniform groundwater flow.

Effect of solute clusters on plastic instability in magnesium alloys

The interaction between solute atoms and matrix dislocations during plastic deformation of materials strongly influences the flow behavior and can lead to plastic instability at the macroscopic scale. In this study, Lüders band formation and dynamic strain aging phenomena were investigated in a Mg–1%Mn-1%Nd (wt.%) alloy, deformed in uniaxial tension at ambient temperature and 150 °C. The investigated alloy was studied in the initial as-extruded state and after a subsequent heat treatment at 275 °C for 120 min, which allowed for a variation of solute concentration in the microstructure, and thus for a different type/level of solute – dislocation interaction. Microstructure investigations at near-atomic resolution using three dimensional atom probe tomography were carried out in order to visualize the spatial distribution of alloying elements and reveal potential solute clustering trends in connection with the occurrence of plastic instability. Identified nanoscale solute clusters were analyzed on the basis of their size distribution, chemical composition, and statistical significance. Results demonstrate that the number, as well as the types of solute clusters, play an essential role in triggering plastic instability by interacting with deformation carriers at the atomic scale.

Increasing ionic strength and valency of cations enhance sorption through hydrophobic interactions of PFAS with soil surfaces

The effect of soluble cations on sorption in soils of a range of anionic PFAS is not well studied. We investigated the role of three common cations (Na+, Ca2+, and Mg2+) at varying solution concentrations on the sorption coefficients (Kd) of 18 anionic PFAS in two contrasting soils. The effective charge of the soil suspension (Zeta potential) became less negative as the concentration of these cations increased in the soil solutions. Perfluorinated compounds showed greater sorption than polyfluorinated compounds, with sulfonates of comparable chain lengths showing higher sorption than the carboxylates. We observed that the Kd values of several PFAS in the two soils were positively correlated with the concentration of cations in solution, especially in the presence of polyvalent cations (Ca2+and Mg2+). The changes in sorption with cation concentration were more prominent for long-chain PFAS, with C > 10 PFAS being completely removed from solution at higher cation concentrations. The emerging PFAS (replacement compounds GenX and ADONA) showed negligible or little sorption (Kd < 0.6 L/kg). While several mechanisms contribute towards sorption of PFAS in the presence of cations, we conclude that the primary effect of cations is through screening of negative charges on head groups of PFAS and reorientation of molecules at the interface between organic matter surfaces and soil solution as well as charge neutralisation at soil solid surface. Screening of negative charges allows for greater hydrophobic interaction between hydrophobic tails of PFAS and soil surfaces resulting in greater sorption. Increasing cation concentrations in soil solutions could thus reduce mobility of PFAS through a soil profile.

Evaluation of Antimicrobial Efficacy of Titanium Dioxide on Dental Plaque Colonisers: An In-vitro Study

Introduction: Denture Stomatitis (DS), a common inflammatory condition of the denture bearing mucosa amongst denture wearers is strongly related to poor denture hygiene. Various materials have been incorporated into denture base acrylic resins to have an antimicrobial effect. The antimicrobial efficacy of Titanium dioxide (TiO2 ) on denture base acrylic resins has been demonstrated; however, studies are lacking in assessing the effective dose concentration of TiO2 in inhibiting microorganisms present in denture plaque. Aim: To investigate the effectiveness of TiO2 coating on denture base acrylic resin in inhibiting colonisers of denture plaque. Materials and Methods: The in-vitro study was conducted in the Department of Prosthodontics and Crown &amp; Bridge and Department of Microbiology, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India between August 2021 to September 2021. Stock solutions of various concentrations of TiO2 were prepared to evaluate the effective dose concentration. Forty specimens of heat cure acrylic denture base resin were divided into two groups: an uncoated group (n=20) and TiO2 coated group (n=20). They were further subdivided into 4 groups, namely specimens containing Streptococcus sanguinis, Staphylococcus aureus, Candida albicans, and specimens containing a mixture of the above organisms. After inoculating, the specimens were UV treated, incubated for 24 hrs, and then washed with phosphate buffer saline. Subcultures were obtained and microbial growth colonies were measured using automated bacterial colony counter. The obtained results were subjected to statistical analysis (SPSS software version 21) and Mann-Whitney U test to compare between the groups, p value of less than or equal to 0.05 (p≤0.05) was considered significant. Results: Colonisers of denture plaque in the uncoated acrylic group was higher (mean:12973.33, 441998.33, 9126.66, and 13.3 CFU) when compared to the TiO2 coated acrylic resin group (mean:1, 0.99, 1, and 1 CFU). The obtained results between the groups was statistically significant (p≤0.05). Conclusion: TiO2 coating on denture base acrylic resin can inhibit the growth of microorganisms associated with denture plaque.

Effects of alkali treatment on properties of willow bark fiber as potential fillers for polymer composites

In this work, willow fiber was extracted from willow inner bark and modified with alkali solution of various concentrations, temperature and time. The morphology, surface functional group, crystal and thermal stability were investigated by using a scanning electron microscopy, a Fourier transform infrared spectroscopy, an X-ray powder diffractometer, and a simultaneous thermal analyzer, respectively. The acid (H2SO4, 2 ml/l) extraction procedure removed the hemicellulose and part of lignin from willow bark, cleared the aggregation of WB, kept the crystal structure of willow fiber, dramatically increased the crystal length of fiber (from 18.46 to 30.15 nm), and enhanced the onset degradation temperature (from 262.23℃ to 297.62℃) and chemical reactivity (DTG: from 0.57%/s to 0.84%/s). The alkali treatment further removed lignin from willow fiber, smoothed the fiber surface, increased the intensity of cellulose [Formula: see text] from 646 counts to 1292 counts, and lengthened the crystal length from 30.15 to 41.84 nm. Varying the alkali treating condition, the crystal index and thermal stability reached to the climax at 60℃ of treating temperature and 7 h treating time. The treated willow fiber may have potential applications to composite with polymer, and to be used in pharmaceutical field as additives.

A Feasibility Study of Non-invasive Blood Glucose Level Detection Using Near-Infrared Optical Spectroscopy

Diabetes mellitus, a common disease of the modern era, is a glucose level disorder in the human body that affects the vital organs of the body and damages them gradually if left untreated. Regular blood glucose monitoring is one of the prescribed routines to control the complications of diabetes. Unfortunately, most available methods of blood glucose level measurement involve invasive ways. Invasive techniques are painful, make the finger skin calloused and the patients suffer from the risk of infectious diseases. Hence, there lies a need to develop an effective non-invasive blood sugar measurement technique to relieve the patients from the nuisance. In order to address the issue, a non-invasive technique has been designed and implemented using 940 nm near-infrared (NIR) LED and a corresponding photodiode. Initially, the in-vitro test was performed over the glucose solution of various concentrations to check the sensitivity of the device. After that pilot experiments were carried out on diabetic patients. The obtained results conformed the theory of near infra-red spectroscopic optical theory. The results also showed that the developed technique can be comparable with the conventional invasive glucometer based method. Furthermore, the implemented prototype is economically viable, especially for the low-income population. This promising results thus pledge the potentials, feasibility, and reliability of the NIR based non-invasive blood glucose detection devices.&#x0D; Bangladesh Journal of Medical Physics Vol.14 No.1 2021 P 1-13

Effect of chlorine dioxide on avian influenza A (H7N9) virus

Avian influenza remains a threat to human wellbeing. Hypochlorite derivatives are commonly used as disinfectants to prevent the spread of the disease. The World Health Organization (WHO) has listed chlorine dioxide (ClO2) as an A1-level, safe, and efficient disinfectant. In this study, we tested the efficacy of ClO2, in aqueous solution and gas forms, against avian influenza A (H7N9) virus. The virus suspension was mixed with ClO2 aqueous solutions of various concentrations and for various time intervals. Aliquots of the mixture were then serially diluted, and the 50% tissue culture infective dose (TCID50) was measured with a hemagglutination test on MDCK cells. ClO2 gas produced from generators was introduced in a chamber containing the virus suspension in a Petri dish. The infective activity of the surviving virus was measured by the hemagglutination test. An aqueous solution of ClO2 at 126 µg/mL for 15 s was effective given that no surviving virus was detected with the hemagglutination test. ClO2 gas at >5 µL/L sustained for 1 h inactivated the virus effectively, while at 2.5 µL/L for 1 h, it only partially inactivated the virus. ClO2 as gas or aqueous solution at a certain concentration is effective in inactivating the H7N9 virus, and can be applied for the decontamination and disinfection of environments.

Laboratory Measurements of Zeta Potential in Fractured Lewisian Gneiss: Implications for the Characterization of Flow in Fractured Crystalline Bedrock

Despite the broad range of interest and possible applications, the controls on the electric surface charge and the zeta potential of gneiss at conditions relevant to naturally fractured systems remain unreported. There are no published zeta potential measurements conducted in such systems at equilibrium, hence, the effects of composition, concentration and pressure remain unknown. This study reports zeta potential values for the first time measured in a fractured Lewisian gneiss sample saturated with NaCl solutions of various concentrations, artificial seawater and artificial groundwater solutions under equilibrium conditions at confining pressures of 4 MPa and 7 MPa. The constituent minerals of the sample were identified using X-ray diffraction and linked to the concentration and composition dependence of the zeta potential. The results reported in this study demonstrate that the zeta potential remained negative for all tested solutions and concentrations. However, the values of the zeta potential of our Lewisian gneiss sample were found to be unique and dissimilar to pure minerals such as quartz, calcite, mica or feldspar. Moreover, the measured zeta potentials were smaller in magnitude in the experiments with artificial complex solutions compared with those measured with NaCl, thus suggesting that divalent ions (Ca2+, Mg2+ and SO42−) acted as potential determining ions. The zeta potential was also found to be independent of salinity in the NaCl experiments, which is unusual for most reported data. We also investigated the impact of fracture aperture on the electrokinetic response and found that surface electrical conductivity remained negligibly small across the range of the tested confining pressures. Our novel results are an essential first step for interpreting field self-potential (SP) signals and facilitate a way forward for characterization of water flow through fractured basement aquifers.

JELLY FOOD CONCENTRATE WITH ENCAPSULATED HIBISCUS EXTRACT

Background. Taking into consideration the intense rhythm of life, the development of technologies for instant food products of increased nutritional value is urgent. Typically, food concentrates for desserts include fruit or fruit and berry fillings and require cooking to prepare ready-made meals. In this case, heat treatment of the mixture (boiling) negatively affects the thermolabile biologically active compounds. The aim of the work was to develop a recipe for instant food jelly concentrates of increased nutritional value based on encapsulated powdery hibiscus extract. Materials and methods. To encapsulate the aqueous-alcoholic extract of hibiscus and obtain a powdered semi-finished product, swelling potato starch was used. Rheological studies were carried out using a "REOTEST-2" rotational viscometer. Results. In order to enrich food concentrates of instant kissel with biologically active substances, we studied a method for extracting dry hibiscus flowers with aqueous-alcoholic solutions of various concentrations. It was found that the extractivity and the transfer of polyphenolic compounds, including anthocyanins, to the extract are improved when a water-alcohol mixture with an ethyl alcohol concentration of 30 % is used as an extractant. For the preparation of a powdery hibiscus extract, modified swelling starch was used, which has the property of swelling in cold water, which makes it possible not to subject the mixture to prolonged heat treatment for preparing a ready-made dish and to preserve the biologically active substances of the hibiscus extract. In addition, this starch is an effective solid carrier that plays a protective role for thermolabile vitamins and bioflavonoids. On the basis of experimental studies, formulations of instant jelly have been developed, which include fructose, powdered hibiscus extract, apple pectin and ascorbic acid. The study of the rheological properties of semi-finished products based on hibiscus extract, as well as ready-made jelly, testifies to the receipt of a finished dessert with a delicate creamy consistency. Conclusion. A method for obtaining a powdery encapsulated hibiscus extract based on swelling potato starch and a composition of a food jelly concentrate using this semi-finished product have been developed. It was found that for the extraction of raw materials it is better to use a water-alcohol mixture with an ethanol content of 30 %, since most of the anthocyanins are converted into the extract under these conditions. The developed semi-finished product of dry hibiscus extract can be used as a thickener, acidifier and colorant in recipes for food concentrates for instant dessert dishes. Due to the use of swelling starch, food concentrates of jelly do not need to be boiled, and the presence of vitamins, organic acids, flavonoids and especially anthocyanins in the hibiscus extract increases the nutritional value of the finished product.

Preparation of 1060, 2024 and 7075 Aluminum Alloy Anodic Oxide Films

On aluminum alloys of grades 1060, 2024 and 7075, regular and highly uniform oxide films were formed by anodic oxidation. Anodizing was carried out at a constant pressure in a phosphoric acid solution of various concentrations. Using scanning electron microscopy (SEM) and X-ray diffraction (XRD), the optimal characteristics of the method of anodic oxidation for forming uniform oxide films on aluminum alloys were determined: anodic oxidation time, temperature, voltage and the concentration of H3PO4. It was found that, in the process of anodizing, the films have gone through four stages: a non-porosity stage, a mixed stage, an ordered porosity stage and a disordered porosity stage.

Direct fabrication of high performance moisture-driven power generators using laser induced graphitization of sodium chloride-impregnated cellulose nanofiber films

High performance moisture-driven power generators were developed by laser induced graphitization (LIG) of sodium chloride-impregnated cellulose nanofiber films (CNFs). CNFs impregnated with different amounts of NaCl were obtained by immersing CNFs in NaCl solutions of various concentrations. A CO2 laser engraver was employed to convert the CNFs to porous graphitic carbon films (GCFs) under ambient conditions. By focusing the laser beam on the top surface of the CNF, the laser intensity was the highest on the top surface and gradually decreased toward the bottom surface. Since the focal temperature of the laser beam was higher than the boiling point of NaCl, the NaCl particles near the top surface evaporated more rapidly, creating a NaCl concentration gradient along the thickness direction. When the GCF was exposed to moisture, the dissociated ions migrated between the top and bottom surfaces, producing an electrical current. The maximum voltage and current outputs were 0.65 V and 550 μA/cm2, respectively, at 90% relative humidity (RH). Due to abundant dissociated ions, the current output was produced continuously rather than pulsed, and was the highest current reported so far. We demonstrated that six vertically stacked GCFs (each 3 mm × 3 mm × 240 µm in size) at 75% RH were sufficient to turn on green light emitting diodes (LEDs) operating at an onset potential of 2 V for 48 h without any auxiliary devices, such as rectifier circuits and capacitors.

Climate Variability Drives Watersheds Along a Transporter‐Transformer Continuum

AbstractWe examined how climate variability affects the mobilization of material from six watersheds. We analyzed one to seven years of high‐frequency sensor data from a temperate ecosystem and a tropical rainforest. We applied a windowed analysis to correlate concentration‐discharge (C‐Q) behavior with climate anomalies, providing insight into how hydrological and biogeochemical processes change in response to climate variability. Positive precipitation anomalies homogenized the C‐Q responses for dissolved organic matter, nitrate, specific conductance and turbidity, indicating that hydrological processes dominate the C‐Q signal and watersheds act as “conveyor belts” of material. In contrast, drier and warmer conditions led to C‐Q behavior associated with variation in solute concentration, suggesting that biogeochemical processes are a primary control on solute export and their response to flow. Results indicate that climate variability can move watersheds along a continuum from transporter‐to‐transformer of biologically active solutes and responses can potentially vary by biome.

The influence of synthetic foaming agents on seed germination of coniferous species

Water is the most frequently used substance for extinguishing of wildfires. Ones of the most commonly used additives enhancing the extinguishing efficiency are foaming agents. This article deals with the influence of foaming agents on germination of coniferous species. Foaming agents Moussol-APS F-15 and Sthamex F-15, foaming solutions of various concentrations were used for the tests. Germination of seeds of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) was observed. The percentage of germinating seeds was recorded every 7 days. The results were evaluated in the form of graphs.&#x0D; When the concentration levels of foaming solutions ranged from 0.1 vol% to 0.25 vol%, their influence on germination of both coniferous species seeds varied from negligible to slightly positive. Subsequently, the negative effect increased considerably and with concentrations exceeding 1 vol% - 1.5 vol% the germination of samples reached zero values. While foaming solutions of Sthamex F-15 showed less significant influence on germination of the Scots pine seeds, seeds of the Norway spruce were less influenced by foaming agent Moussol-APS F-15. Based on obtained results it is possible to recommend minimisation of foaming agents amounts, eventually application of substances with less negative effect on plants germination for extinguishing of wildland fires, in order to gain restoration of affected area as fast as possible. Key words: foaming agent, germination, wildfire (wildland fire), foaming solution

Effect of Non-stoichiometry and oxygen deficiency in In2O3 thin films on gas sensing performance

The non-stoichiometric and oxygen deficiencies in Indium oxide (In2O3) are the key properties which help to improve the gas sensitivity of the In2O3. In2O3 thin films were deposited using simple spin coating method with varying precursor solution concentration. The variation of solution concentration has revealed the systematic growth of leaflet like structure. The In2O3 thin films coated at solution concentration of 0.15 M showed maximum sensor response of ∼ 25.27 at optimum temperature of 200 °C against NO2 gas for 100 ppm concentration. The highest performance of In2O3 gas sensor can be attributed to the defects present in In2O3 as confirmed by PL spectra.

Design of Bridge Type C-Band Planar RF Sensor for Detection of Solute Concentration Level in Water

In this paper, a planar Micro-strip-based bridge topology CSRR is proposed for the detection of various solute concentrations in water sample. The designed bridge topology CSRR (B-CSRR) sensors resonates at 5.18 GHz with a Q-factor of 170, which exhibits a fractional sensitivity (10.17%). To avoid the contamination of test liquids, use of the thin Teflon layer is incorporated on top of the sensor region. The numerical analysis of the sensors for various scenarios including the sensor loaded with several lossy samples are carried out and accordingly shift in resonant frequency is recorded. The optimized design topology helps to attain better electric field confinement at the resonant frequency, which eventually leads to improved dielectric sensitivity. In the next part, an equivalent circuit of the proposed sensor is developed using the Advanced Design System (ADS) software. Afterwards, the designed sensor is fabricated on 0.8mm thick Taconic TLY-5 substrate ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\boldsymbol {\varepsilon }_{r}$ </tex-math></inline-formula> = 2.2). Finally, the measurement of B-CSRR sensor is carried out for different solute concentration in pure water, which is in present scenario are salt and detergent concentration, respectively. The developed sensor is found to be quite sensitive which produces a substantial change in the measured insertion loss even for small variation in solute concentration. For instance, a typical 2% variation in detergent, and salt concentration leads to nearly 1.5 dB, and 2.0 dB, change in measured S21.

THE INFLUENCE OF THE SALTITY OF THE MOISTURIZING SOLUTION ON THE DIELECTRIC PERMEABILITY OF CLAYS IN THE FREQUENCY RANGE FROM 1 MHZ TO 8 GHZ

The article presents the results of measurements of the complex dielectric constant of clays saturated with NaCl solution of various concentrations in a wide frequency range. The measurements were carried out at positive temperatures. It was revealed that several relaxation processes are observed in the spectra. A model is proposed that makes it possible to take into account the relaxation processes and their dependence on the concentration of the salt solution. The concentration practically does not affect the parameters of the processes, in contrast to the temperature.