Additive Concentration Research Articles

The addition of ascorbic acid improves the microbiological quality and shelf life of Atlantic mackerel (<i>Scomber scombrus</i>) fillets stored in ice

Ascorbic acid is one of the most promising additives for improving fish shelf life, but studies on its antimicrobial activity during product storage are limited. In this experiment, we assessed the effect of ascorbic acid on the preservability of Atlantic mackerel (Scomber scombrus) fillets during storage in ice. Fillets were treated to reach an ascorbic acid concentration of 0.30 mg/g (T1) and 0.15 mg/g (T2). Samples were stored in ice at 0°C and analyzed at 0, 2, 7, 9, and 14 days for total viable count, specific spoilage organisms (SSOs), Pseudomonas spp., potentially histamine-producing bacteria (HPB), and Enterobacteriaceae. Growth curves were constructed using the DMfit tool of Combase, and the shelf life was estimated in relation to microbiological limits reported in the literature. Sensory evaluation was performed using a quality index method scheme. At 7 and 9 days of storage, treated samples exhibited bacterial counts from 0.5 to 1.7 Log CFU/g lower than controls, with a logarithmic reduction proportional to the additive concentration. The antimicrobial action appeared to diminish after 14 days. A consistent effect was observed for potentially HPB, with counts of 1.7 Log CFU/g lower in T1 samples compared to controls at 9 days. The moderate effect on SSOs limited the estimated shelf life, as the critical limit was reached after 7 days and 8.4 days (T1 and T2). Ascorbic acid positively impacted the microbiological characteristics of mackerel fillets. Further investigation into the decay dynamics of the additive in fish products during storage is advisable.

Density functional theory of freezing transition in a binary mixture of spheres and soft-ellipsoids

ABSTRACT This study uses the classical density functional theory (DFT) of freezing to investigate phase transitions in ellipsoidal-spherical binary mixtures interacting via a generalised Gay-Berne (GB) intermolecular potential, with a focus on I-N, I-SmA and N-SmA transitions. The mixtures, consisting mainly of ellipsoids, contain spherical additives at concentrations of 5 % , 10 % and 15 % . The pair correlation functions, which are crucial for the DFT, are derived from Percus-Yevick integral equation theory. Our results show a significant influence of spherical additives on liquid crystalline phases formed by ellipsoids. At an ellipsoid length-to-width ratio of 3.0, only the I-N transition is observed, with the SmA phase remaining unstable under all conditions. Increasing the ellipsoidal length-to-width ratio to κ = 4.0 introduces the SmA phase, whose stability depends on the concentration and size of the spherical additives. The stability of the SmA phase decreases with increasing concentration and size of the spheres. Phase diagrams, which are shown in temperature-density and pressure-temperature planes, emphasise the influence of the size of the spherical dopants on the phase stability.

“Hexacelsian slurry development for 2D woven alumina fiber impregnation in CMC fabrication”

The rheological properties of BAS (BaAl2Si2O8) slurries are investigated in order to optimize the impregnation of an alumina preform to manufacture oxide/oxide composite materials. The fiber preform morphology has been deeply investigated, especially the fiber to fiber gap within tows and compared to the grain size of the matrix powder. The slurry viscosity is measured as a function of powder and organic additives concentration to find the best combination. The optimal combination is evaluated by different measurements including: zeta potential, sedimentation and wettability to verify the slurry behavior for the fibers infiltration. An aqueous slurry containing 20–25 vol% of BAS with 1 wt% of dispersing agent (Darvan 821-A™) improved the rheological properties for fibers infiltration. Finally, characterizations of the composite show a good infiltration in the fiber tows spaces and indicate a mean porosity of 37 vol%, including 9 vol% of macroporosity.

Determination of biological activity of ethanol extracts of date-plum (Diospyros lotus) fruits and seeds growing in Turkey

This study was carried out to evaluate quality criteria such as chemical composition and antioxidant and antibacterial activity values in 80% ethanol extracts of date-plum (Diospyros lotus) fruits and seeds. In addition, the macro and microelement concentrations of fruits and seeds were also investigated. According to the data obtained, when fruit and seed were compared, it was determined that the seed (81.72%) contained more components than the fruit (79.4%), and the antioxidant activity of the seed was also higher. While the main component of the seed was “Methyl hydrogen disulfide” with 43.21%, the main component of the fruit was “5-Hydroxymethylfurfural” with 24.2%. As a result of antimicrobial activity tests, neither seeds nor fruits have antimicrobial activity. At the same time, the nutritional content values of the seeds and fruits of this plant were analyzed and evaluated. When the data obtained are evaluated in terms of both macro and micronutrients, it has been observed that the nutritional content values of the fruit (K (3.63%), P (0.68 %), Cu (24.31%), Zn (10.49 mg kg–1) and Mn (25.29 mg kg–1) for fruits) are higher than the seeds. In conclusion, the findings from the evaluation of Diospyros lotus fruit and seeds in this study highlight the richness in chemical composition and high antioxidant activity of the seeds, as well as the nutritional superiority of the fruit. Therefore, further research to better understand and harness the potential health benefits of this plant could contribute to a deeper understanding of this field.

Analytical Method Development by Using UV-Spectrophotometer for Estimation of Valsartan in Bulk

In order to accurately determine valsartan (API), this work aims to build a straightforward and exact UV spectroscopic approach. To improve sensitivity and accuracy, the procedure entails methodically optimizing experimental parameters, including solvent choice and wavelength selection. The produced stock solutions were tested for absorbance at 249 nm using a UV spectrophotometer. With %RSD values below 2% for both intra- and inter-day, the devised approach was determined to be quite accurate. At each additional concentration, the approach was shown to be accurate, yielding good drug recoveries ranging from 98 to 101%. The process was validated for linearity, specificity, accuracy, precision and limit of detection (LoD) and limit of quantification (LoQ) as per International Council of Harmonization (ICH) criteria. Its dependability for quantitative analysis of valsartan in pharmaceutical formulations was demonstrated. This UV spectroscopic approach offers a cost-effective and efficient alternative for routine quality control in pharmaceutical industries.

Tribological Properties of Nano-Scale Al2O3 Particles with Different Shapes as Lubricating Oil Additives

Enhancing lubrication across various tribological systems in the maritime industry is essential for improving safety, efficiency, and environmental sustainability. Al2O3 nanoparticles, employed as additives in lubricating oils, demonstrate favorable tribological properties including anti-wear and anti-friction characteristics. In this work, nano-scale γ-Al2O3 particles with different shapes, i.e., nanosheet, nanorod, nanosphere, and irregular-shaped nanoparticles, were prepared and calcinated forming the same crystalline phase with nanoscale size, which dispersed well in lubricating oil. The tribological properties of Al2O3 nanoparticles as lubricating oil additives were examined using block-on-ring wear tests, and the effects of the particle shape and particle concentration were investigated. The results indicated that the frictional properties are largely influenced by the particle shape and the concentration of the Al2O3 additives, with the optimal concentration being around 0.1 wt% for each shape. The lubricating oil with nanosheet additives presented the best tribological performance, followed by those with nanorod, nanosphere, and irregular-shaped Al2O3 nanoparticle additives. Al2O3 nanosheets as the lubricating oil additives reduced the stress effect on the friction surface because of their larger bearing area and are inter-particle-sheared during sliding due to the movement of friction pairs, which can further improve the tribological properties compared to other shapes.

Synthesis of a water‐soluble high hydroxymethyl content phenolic resin crosslinker and the associated polyacrylamide weak gel property investigation

AbstractAs an in‐depth profile control agent, water‐soluble phenolic resin crosslinking polyacrylamide weak gel has been widely used in the middle and high water cut stage of water flooding reservoir. In this study, the phenolic resin was synthesized by two‐step alkali catalysis. Factors influencing the synthesis of phenolic resin, including the molar ratio of phenol and formaldehyde, catalyst types, reaction time, were investigated with hydroxylmethyl and aldehyde content as the criterion. When the molar ratio of phenolic resin was 1:2 and NaOH was catalyst, at 80°C for 4 h, the phenolic resin had the highest hydroxymethyl content (49.37%) and the lowest free aldehyde content (2.95%). Weak gel was formed by the reaction of LT002‐polyacrylamide with phenolic resin. Taking the gelation time and strength as criteria, the factors influencing the crosslinking property, including hydroxymethyl content, crosslinker addition, and polyacrylamide concentration were investigated respectively. Under optimal formulation, the property investigation shows that the hydroxymethyl group in the phenolic resin can be crosslinked with the amide group in polyacrylamide, the gelation time is long (50–60 h), and the gelation strength is larger than 5 × 104 mPa s, which is conductive to the plugging of deep oil layers. When the permeability was 5061 × 10−3 μm2, the plugging rate was 72.73%.

Fatty acid profile, physicochemical composition and carcass traits of young Nellore bulls fed Acacia mearnsii extract

Fatty acid profile, physicochemical composition, and carcass traits of 32 young Nellore bulls were assessed following the supplementation of Acacia mearnsii extract at levels of 0, 10, 30, and 50 g/kg of total dry matter (DM) in a completely randomized experiment with four treatments and eight replicates. Adding 50 g/kg DM of condensed tannins (CT) from Acacia mearnsii in the bulls' diet reduced DM intake, average daily gain, and meat lipid oxidation (P ≤ 0.05). The pH, centesimal composition, collagen, and meat color indexes of the longissimus muscle were not altered by the addition of Acacia mearnsii (P > 0.05). Cooling loss increased (P = 0.049) linearly. Including Acacia mearnsii in diet reduced the Warner-Bratzler shear force (WBSF, P = 0.018) of longissimus muscle of the bulls. The concentration of C16:0, C17:0, C24:0, t9,10,11,16–18:1, c9t11–18:2, C18:2n–6, C20:4n–6, 20:5n–3, 22:5n–3, and 22:6n–3 in the muscle increased due to the addition of Acacia in the diet (P ≤ 0.05), with the highest muscle concentrations caused by the addition of 10 to 30 g Acacia. c9–18:1 and t16–18:1 reduced linearly. ƩSFA, ƩBI, Ʃcis– and ƩMUFA, Ʃn–3, Ʃn–6, and ƩPUFA (P ≤ 0.05) quadratically increased at higher concentrations of addition of Acacia, above 30 g/kg DM. It is recommended to include Acacia mearnsii extract up to 30 g/kg total DM in diets for young bulls as it improves CLA, PUFA and TI and reduces lipid oxidation. Acacia mearnsii extract as source of CT at 50 g/kg DM negatively impacted the young bulls performance.

Evaluation of Various Concentrations of Rumen Waste in making Liquid Organic Fertilizer

Slaughterhouses are known as places to produce meat for human consumption. On the other hand, slaughterhouses produce livestock waste, one of which is rumen. The rumen's high nutrient and microbial content provide an excellent opportunity for its use as liquid organic fertilizer for plant growth and development. However, evaluation of rumen addition concentration during the manufacture of liquid organic fertilizer is still scarce and needs to be carried out. Therefore, this research aims to obtain a suitable rumen addition formulation for making liquid organic fertilizer. Rumen waste was varied in 4 concentrations, namely 20%, 40%, 60% and 80%. Supporting ingredients, such as laos, ginger, turmeric, galangal, and rice washing water, are mixed with the rumen, which is then incubated for 15 days to obtain liquid organic fertilizer. Analysis of total nitrogen content, C/N ratio, total phosphate, total potassium, total microbes, and physical characteristics was carried out to evaluate the quality of liquid organic fertilizer. The results showed that the addition of 80% rumen was able to play a role in producing liquid organic fertilizer with high total nitrogen (2.35%), low C/N ratio (6.05), high total phosphate (1.19%), and high total potassium (1.75%). Furthermore, liquid organic fertilizer made with the addition of 80% rumen contains high total microbes (5.5 x 1010 CFU/mL), is bright brown, yellowish in color, and has an earthy aroma. This research indicates that adding 80% rumen can produce good quality liquid organic fertilizer. This information can be the basis for further research regarding the rumen potency as an ingredient of organic fertilizer.

Response of Stand Spatial Structure to Nitrogen Addition in Deciduous Broad-Leaved Forest in Jigong Mountain

Significant influences on tree growth and forest functionality are attributed to nitrogen (N) addition. However, limited research has been conducted on the effects of N addition on forest spatial structure. In this study, we examined the effects of different N addition methods and concentrations on the stand spatial structure of a deciduous broad-leaved forest over the period 2012 to 2017. Five N addition treatments were implemented: CK (control group without N addition), CN25 (low N concentration added to the canopy), CN50 (high N concentration added to the canopy), UN25 (low N concentration added to the understory), and UN50 (high N concentration added to the understory). The results showed a moderate influence of N addition (CN25, CN50, UN25, UN50) on optimizing the stand spatial structure. CN25, CN50, and UN25 increased the mean values of the mingling degree (M) and neighborhood comparison (U), while decreasing the mean value of the uniform angle index (W), although these effects were not significant. Enhancements in the average value of the crowding degree (C) and comprehensive spatial structure index (CSSI) between 2012 and 2017 were found in all five treatments, demonstrating statistical significance. Assessing the distribution of the stand spatial structure index, CN25, CN50, and UN25 increased the proportion of M at an intensity (M = 0.75) and extreme intensity (M = 1), while decreasing the proportion at zero intensity (M = 0), weak intensity (M = 0.25), and moderate intensity (M = 0.5). A decrease in the proportion of trees was noted when U = 0 (excluding UN50), with no discernible pattern found in the frequency distribution of other values. CN50 and UN25 increased the proportion of W at a moderate level (W = 0.5), while CN25 and UN50 reduced it. No clear pattern was detected in the frequency distributions of other values. All five treatments increased the proportion of C at the maximum level (C = 1), while decreasing the proportions at levels of 0, 0.25, and 0.5 in 2017. Intriguingly, nitrogen addition treatments appeared to optimize the stand spatial structure to some extent and stimulated the growth of trees with larger diameters. Nevertheless, the short duration of the data collection period, spanning only five years, may have influenced the significance of the outcomes, underlining the requirement for extended studies. Conclusively, N deposition adjusted and enhanced the stand spatial structure to various degrees within the research region, providing valuable insights for further optimization of forest management.

An economic, accessible and stable sulphated cyclodextrin polymer as selector for efficiently separating chiral drugs in HPLC

In this study, sulfopropyl ether β-cyclodextrin polymer (SPE-β-CDP) with simple synthesis steps using cheap reagents was large-scalely prepared. Characterization results showed the average sulfonic group substitution in each β-CD molecule was about 7.261, and there were 195.87 μmol/g β-CD units in polymer. It was low viscosity and produced a little effect on column pressure. It was used as chiral selectors first time to add into mobile phase to separate 13 chiral drugs in HPLC. After investigation, results showed buffer pH, chiral additive concentration, organic phase proportion in mobile phase and flow rate could affect chiral separation. High separation ability of SPE-β-CDP was proved through baseline separation of 12 drugs which attributed to the homogeneity of SPE-β-CDP in sulfonic acid group substitution degree and position. The resolutions of salbutamol, bisoprolol, chlorpheniramine, propranolol and metoprolol could be even up to 7.47–19.02, which were significantly better than that of some references. Separations of 4 chiral drugs were even better than that of CE. Compared with monomer, SPE-β-CDP showed better chiral separation ability. SPE-β-CDP could be used in both of C8 and C18 columns. It was stable in batches and showed good recyclability and reusability. These provided a new strategy for chiral separation.

Additives Depletion by Water Contamination and Its Influences on Engine Oil Performance

Water enters engine oil in different ways and moves in the lubrication system causing an increase in wear, oil degradation and additives depletion. It has been proposed that water in the lubricants can transfer from dissolved to free phase leading to additives depletion in the oil. Different additives in the lubricants can easily latch to water molecules forming reverse micelles. The separation of reverse micelles from the oil causes additives depletion. This experimental and analytical study aims to investigate how the separation of free water above the saturation level can diminish the efficiency of additives in engine oils. The effect of varied levels of water on oil performance and its additives was investigated in this study. A new saturation method was used to determine the water saturation level in engine oil at different temperatures. The results reveal a decrease in additive concentration with increased separation of free water from the oil. Free water separation from engine oil is expected to reclaim the tribological performance, however, the results demonstrate that tribological performance after the separation of free water from the oil has been affected. The study showed not only does the removal of free water diminish the efficiency of additives due to additives depletion (≈ 10 wt%), but also the remaining dissolved water which is ≈ 2600 ppm can also affect wear and tribofilm chemistry. The results prove that two main mechanisms influence oil performance expressed as additives depletion by free water and remaining dissolved water.

MmpR5 protein truncation and bedaquiline resistance in Mycobacterium tuberculosis isolates from South Africa: a genomic analysis

The antibiotic bedaquiline is a key component of new WHO regimens for drug-resistant tuberculosis; however, predicting bedaquiline resistance from bacterial genotypes remains challenging. We aimed to understand the genetic mechanisms of bedaquiline resistance by analysing Mycobacterium tuberculosis isolates from South Africa. For this genomic analysis, we conducted whole-genome sequencing of Mycobacterium tuberculosis samples collected at two referral laboratories in Cape Town and Johannesburg, covering regions of South Africa with a high prevalence of tuberculosis. We used the tool ARIBA to measure the status of predefined genes that are associated with bedaquiline resistance. To produce a broad genetic landscape of M tuberculosis in South Africa, we extended our analysis to include all publicly available isolates from the European Nucleotide Archive, including isolates obtained by the CRyPTIC consortium, for which minimum inhibitory concentrations of bedaquiline were available. Between Jan 10, 2019, and July, 22, 2020, we sequenced 505 M tuberculosis isolates from 461 patients. Of the 64 isolates with mutations within the mmpR5 regulatory gene, we found 53 (83%) had independent acquisition of 31different mutations, with a particular enrichment of truncated MmpR5 in bedaquiline-resistant isolates resulting from either frameshift mutations or the introduction of an insertion element. Truncation occurred across three Mtuberculosis lineages, and were present in 66% of bedaquiline-resistant isolates. Although the distributions overlapped, the median minimum inhibitory concentration of bedaquiline was 0·25 mg/L (IQR 0·12-0·25) in mmpR5-disrupted isolates, compared with 0·06 mg/L (0·03-0·06) in wild-type M tuberculosis. Reduction in the susceptibility of M tuberculosis to bedaquiline has evolved repeatedly across the phylogeny. In our data, we see no evidence that this reduction has led to the spread of a successful strain in South Africa. Binary phenotyping based on the bedaquiline breakpoint might be inappropriate to monitor resistance to this drug. We recommend the use of minimum inhibitory concentrations in addition to MmpR5 truncation screening to identify moderate increases in resistance to bedaquiline. US Centers for Disease Control and Prevention.

Hydrogen/deuterium exchange in 1-alkyl-3-methylimidazolium-based water and methanol solutions

The hydrogen/deuterium (H/D) exchange of ionic liquid (IL) occurred in the deuterated solutions. Kinetic H/D exchange was investigated via Raman spectroscopy and pH measurements. The ILs employed were amphiphilic 1-alkyl-3-methylimidazolium triflate ([Cnmim][OTf] (n = 2, 4, 6, and 8)) and hydrophilic [C2mim][X] (X = Cl, Br, I, and BF4). The H/D exchange occurred in the [C2mim][OTf]-deuterated methanol (MeOD-d4) solutions and was dependent on the additive concentration. For [C2mim][X]-D2O (X = Cl, Br, and I), which did not possess nano-heterogeneity and the anionic anisotropic shape factor, significant relationships were observed among the H/D exchange rate, pD, and ion-pairing strength.

Addition of S-servicia Dry Yeast at Different Densities and its Effect in Some Productive Traits of Quail

Background: Dry yeast is considered a food additive that is used as a probiotic. In this study, it was added to the diet of quails that were raised at different densities to enhance growth and raise production performance, especially with the high density of birds per unit area. Methods: This research was conducted in the field of poultry production, College of Agriculture and Forestry/University of Mosul, (50 days) to study the effect of adding yeast in concentrations of (0, 2, 4, 6) gram/liter of drinking water with three densities of breeding (56, 72, 88) birds/m2 for the purpose of identifying the productive performance and some characteristics that are related to egg production for quail birds. Result: Statistical analysis showed that: - Average body weight, weight gain and feed consumption increased significantly with increasing the density, while the feed conversion factor decreased with the increase of egg mass at a density of 72 birds/m2. From the other hand, the egg weight increased significantly at the density of 88 birds/m2. - Body weight and weight gain increased significantly with increasing the amount of the yeast added and the consumed feed decreased with the improvement in the feed conversion factor. Moreover, there was a significant increase in egg mass, both of the weight of egg, yolk, albumin, shell, egg length, height of yolk and albumin. - The combination 72 bird/m2 +4 gm yeast gave the best body weight, weight gain, egg mass, while the conversion factor decreased with the addition of yeast for all densities in addition to a significant increase in the weight of each of egg, yolk, albumin and the shell. The feed consumption increased significantly in the density 88 bird /m2 with different concentrations of yeast addition.

Supplemental effect of Pediococcus acidilactici CNCM I-4622 probiotic on the laying characteristics and calcium and phosphorus metabolism in laying hens

The close link between intestinal microbiota and bone health (‘gut-bone’ axis) has recently been revealed: the modulation of the amount and nature of bacteria present in the intestinal tract has an impact on bone health and calcium (Ca) metabolism. Probiotics are known to favorably impact the intestinal microbiota. The objective of this study was to investigate the effect of Pediococcus acidilactici CNCM I-4622 (PA) on laying performance, egg/eggshell quality, Ca metabolism and bone mineralization and resistance in relatively old layers (50 wks old at the beginning of the experiment) during 14 weeks. 480 Hy Line brown layers were divided into 2 groups (CON and PA: 3 layers/rep, 80 rep/group) and fed with a diet formulated to be suboptimal in calcium (Ca) and phosphorus (P) (− 10% of the requirements). The total egg weight was improved by 1.1% overall with PA, related to an improvement of the weight of marketable eggs (+ 0.9%). PA induced a decreased % of downgraded eggs, mainly broken eggs (− 0.4 pts) and FCR improvement (− 0.8% for all eggs, − 0.9% for marketable eggs). PA also led to higher Haugh units (HU: + 7.4%). PA tended to decrease crypt depth after the 14 weeks of supplementation period in the jejunum (− 25.2%) and ileum (− 17.6%). As a consequence, the VH/CD ratio appeared increased by PA at the end of the trial in the jejunum (+ 63.0%) and ileum (+ 48.0%). Ca and P retention were increased by 4 pts following PA supplementation, translating into increased bone hardness (+ 19%), bone cohesiveness (+ 43%) and bone Ca & P (+ 1 pt) for PA-supplemented layers. Blood Ca and P were respectively improved by 5% and 12% with PA. In addition, blood calcitriol and osteocalcin concentrations were respectively improved by + 83% and + 3% in PA group at the end of the trial, compared to CON group. There was no difference between the 2 groups for ALP (alkaline phosphatase) and PTH (parathyroid hormone). PA significantly decreased the expression of the following genes: occludin in the small intestine, calbindin 1 in the ovarian tissue and actin B in the bone. PA therefore improved zootechnical performance of these relatively old layers, and egg quality. The parallel increase in Ca and P in the blood and in the bone following PA supplementation suggests an improvement of the mineral supply for eggshell formation without impacting bone integrity, and even increasing bone resistance.

Structural and viscosity studies of dendritic hyper branched polymer as viscosity index improvers

Star-like structural compounds were synthesized from different moles % of either dodecyl acrylate or triethylenetetramine using a one-pot commercial synthesis technique. The polymers that were created had various terminations. Fourier Transform Infrared (FTIR) spectroscopy and 1HNMR were used to verify the produced polymers' chemical composition with different terminations. Furthermore, by analysis of Dynamic Light Scattering (DLS), the size and distribution of the synthesised branched polymers were evaluated. Using a Gel-permeation chromatograph, the modified hyperbranched polymer's molecular weight, synthesized with various end points, were assessed. The unorganized structured prepared compounds with various molar feed ratios dodecyl acrylate: triethylenetetramine (DDA: TETA) was designed as A, B, C, D and E. Moreover, the synthesized additives function as viscosity index improvers (VII). As the concentration of polymeric additives increases, it leads to higher VI values. Similarly, with the increase in percentage of triethylenetetramine in the prepared hyperbranched polymers, the VI also increases. Notably, the most effective VI achieved is (E) = 212. It is noteworthy that all the synthesized hyperbranched polymers exhibited Newtonian behavior in the rheological study.

Molecular dynamics study of the temperature dependence of viscosity and thermal conductivity of molten salts FLiNaK and FLiNaK with LaF3 or NdF3

In this work, the temperature dependence of the viscosity and thermal conductivity of molten systems FLiNaK and FLiNaK-MeF3 (Me = La, Nd) was studied using the molecular dynamics method with Born-Mayer-Huggins potential. The dependencies were obtained in the temperature range of 800 < T < 1020 K, as well as for the concentration of lanthanide fluoride additives up to 15 mol.%. The temperature behavior of these kinetic properties is explained based on an MD model of dynamic ionic connectivity. The main contribution to the connectivity of pure FLiNaK ions is made by Li-F ion pairs, and in the presence of LaF3 and NdF3 dissolved in the salt mixture, the connectivity in the system is supplemented by ion pairs formed by lanthanides with fluorine. Both viscosity and thermal conductivity decrease with increasing temperature and rise when lanthanide trifluorides are added to the molten salt.

Development and characterization of semi-refined iota carrageenan/fish gelatin-based biocomposite film incorporated with SiO2/ZnO nanoparticles

Food packaging based on natural polymers from polysaccharides and proteins can be an alternative to replace conventional plastics. In the present study, semi-refined iota carrageenan (SRIC) and fish gelatin (FG) were used as polymer matrix film with different concentration ratios (0.5:1.5 %, 1.0:1.0 % and 1.5:0.5 % w/w) and SiO2-ZnO nanoparticles were incorporated as fillers with the same concentration in all formulas (0.5:1.5 % w/w carrageenan-fish gelatin). This study aimed to develop films for food packaging applications with desirable physical, mechanical, optical, chemical, and microbiological properties. The results showed that incorporating SiO2-ZnO nanoparticles significantly (p < 0.05) improved the films' elongation at break, UV-screening properties, and antimicrobial activity. Also, the films' thickness, degradability, and transparency significantly (p < 0.05) increased with the higher concentration of fish gelatin addition in the SRIC matrix polymer. The best formula was obtained on the SRIC-FG film at the ratio of 1.5:0.5 % w/w, which performed excellent antimicrobial activity. Thus, semi-refined iota carrageenan/fish gelatin-based biocomposite film incorporated with SiO2-ZnO nanoparticles can be potentially developed as eco-friendly and intelligent food packaging materials to resolve traditional plastic-related issues and prevent food waste.

Solidification of sodium sulfate saline loess by biomineralization of reactive magnesium oxide binder

This study aims to solidify sodium sulfate saline loess by biomineralization of reactive magnesium oxide (MgO) binder. The impact of Na2SO4 concentration on the viability and urease activity of S. pasteurii, the mechanism and products of biomineralization of MgO, and the effectiveness of the biomineralization-MgO binder in solidifying saline loess with varying salt content (1%, 3%, and 5%) were investigated. Results showed that low and moderate concentrations of Na2SO4 favored bacterial proliferation. However, the presence of Na2SO4 inhibited bacterial urease activity, and the inhibition was more significant at higher Na2SO4 concentrations. In addition, low and moderate concentrations of Na2SO4 decreased the specific urease activity, whereas high concentrations of Na2SO4 significantly increased specific urease activity. S. pasteurii was able to use carbonate ions formed by urea hydrolysis for the mineralization of MgO and to form magnesium carbonate minerals dominated by rosette-like dypingite and hydromagnesite crystals. The primary mechanism involves microbial cells and extracellular polymeric substances leading to partial dehydration of Mg2+ ions from the Mg2+-H2O complex and allowing for further association with carbonate anions to from Mg-bearing carbonates. Unconfined compressive strength tests conducted on the saline loess samples after 7 days of curing revealed a significant influence of urea concentration on the strength of the solidified soil. The optimal urea concentration to obtain a better 7-day UCS ranged from 4 mol/L to 5 mol/L. Furthermore, solidified soil with 5% salinity yielded the highest 7-day UCS and soil with 3% salinity exhibited the lowest 7-day UCS at the same urea concentration. XRD and SEM analysis of the solidified soil samples indicated that the formation of magnesium carbonate minerals in the soil matrix by the biomineralization-MgO binder was responsible for the UCS enhancement. The remarkable 7-day UCS of saline loess solidified with biomineralization-MgO binder demonstrates the effectiveness of this material in curing saline loess.