Amount Of Salt Research Articles

Preparation of salt-free Pleurotus eryngii protein with enhanced colloidal stability and emulsifying properties by ceramic membrane filtration

Fungi proteins represent a potential alternative to animal proteins, which are regarded as a prospective source of edible proteins due to more sustainable and efficient cultivation of fungi. Nevertheless, the extraction of fungi proteins typically involves alkali extraction combined with acid precipitation (AEAP), yielding considerable amounts of salt that causes aggregation and inferior functional properties of proteins. In this study, we put forward a novel extraction method by direct filtration of Na+ and OH− from the alkaline extraction solutions using ceramic membranes. This method enabled the continuous, efficient and cost-effective production of Pleurotus eryngii protein (PEP). The PEP prepared by this technology featured a uniform distribution of nanoparticles (∼129.5 nm) with higher water dispersity, colloidal stability and surface active properties as compared to that prepared by the AEAP method. Moreover, the microstructures of PEP can be tailored with various nanoparticle sizes and size distribution profiles, allowing for the adjustment of long-term stabilities and surface activities. Our study renovated the production technology of fungi proteins to enhance their functionalities as well as the application prospects in the future food industry.

Ecofriendly one-bath waterless dyeing: Systhesis of novel pyrazolone benzothiazole disperse dyes suitable for cotton-containing fabircs in supercritical CO2

Traditional dyeing utilizes a substantial amount of water and necessitates the incorporation of significant quantities of dyes, auxiliaries, and salts, leading to the discharge of highly concentrated organic wastewater and severe water pollution issues. In this study, a novel pyrazolone benzothiazole disperse dye and its triazine disperse reactive dye were designed with the same yellow shade and synthesized. The results showed that the synthesized dyes could successfully realize one-step dyeing of cotton, polyester, and polyester-cotton in supercritical CO2. At 100℃, 24 MPa, 60 min, and 2.5 % (o.w.f.) of dye concentration, the K/S value of polyester-cotton fabric was 8 by using the same amount of disperse dye and disperse reactive dye. When disperse reactive dye was used at 100℃, 24 MPa, 60 min, and the concentration of 1.5 % (o.w.f.), the K/S value of cotton fabrics can reach 7.3, and their σK/S values were less than 0.03 and 0.006, respectively. Moreover, polyester reached the maximum K/S value of 15.96 at 120°C, 24 MPa, 60 min, and a dye concentration of 2.0 % (o.w.f.) with disperse dye. The σK/S value was below 0.045. The fastness of washing and rubbing was above 4. This study provides novel disperse dye structures and dyeing methods for ecofriendly textiles dyeing in supercritical CO2, especially for one-bath low temperature dyeing polyester-cotton fabrics.

Outer Helmholtz plane adsorption regulation to achieve low-concentration of pure propylene carbonate solvent electrolytes compatible with graphite anode

The low melting point and high polarity of propylene carbonate (PC) make it an ideal solvent for electrolytes of lithium-ion batteries (LIBs), but the incompatibility with graphite anode hinders the application. In the present study, a new method is developed to solve this problem from a new viewpoint. Introduction of saturated LiNO3 (0.14 mol L‒1) into pure PC electrolyte containing lithium salt with normal concentration (1.38 mol L‒1) leads to a perfect compatibility with graphite anode. Li/Graphite cell using this pure PC electrolyte shows a reversible capacity of 350.0 mAh g‒1 and a 200-cycle capacity retention of 96.3 %. Further mechanism study and theoretical computation indicate that the NO3‒ anions are adsorbed to outer Helmholtz plane of the electric double layer at the graphite anode interface. This changes the Li+ solvation structure in the electric double layer, facilitating the Li+ desolvation process hence resulting in high compatibility with the graphite anode. The most prominent advantage of the present strategy is that, because of the adsorption of NO3‒ anions to the outer Helmholtz plane, the compatibility with graphite anode could be improved by introduction of tiny amount of Li salt without large change of the bulk phase properties of the electrolyte. This work provides a new understanding of the compatibility from the viewpoint of outer Helmholtz plane, which might deliver new insights for the optimization of electrolytes for LIBs.

Homogeneous Catalysts of RedOx Processes Based on Heteropolyacid Solutions. VI: Developing a Process for Low-Temperature Oxidation of CO with Oxygen

Research on the development of a homogeneous process for low-temperature oxidation of carbon monoxide in the presence of a “platinum group metal + vanadium-containing heteropolyacid (HPA)” catalytic system has been presented. The optimal reaction conditions, ensuring the maximum rate of CO oxidation to CO2, have been determined; for this reaction the kinetic features have been established, and its mechanism has been proposed. It has been shown that homogeneous systems based on PdII complex exhibit high activity and productivity, but have low stability and operate only at pH below 1,5. The stability of the catalyst can be increased by simultaneous introduction of σ- and π-donor ligands into the system; however, it is more effective to use the PtIV complex in the presence of catalytic amounts of palladium salt at a ratio of 100/1. The transition from HPA solutions with a low content of vanadium atoms (H7PMo8V4O40) to solutions of modified compositions (H10P3Mo18V7O84) ensures an increase in the activity and productivity of the system, with the kinetics of CO oxidation being maintained. The combined homogeneous catalyst PtIV + PdII + H10P3Mo18V7O84 remains stable during multi-cycle use without reducing activity, operates without an induction period and can be used at pH range of 1,7–2,0, which simplifies the process equipment.

Efficient treatment of printing and dyeing reverse osmosis concentrate by a Ti‐NTA/SnO2‐Sb2O3 electrocatalytic membrane

AbstractBACKGROUNDPrinting and dyeing reverse osmosis concentrates (ROC) contain large amounts of salts and organic matter, which is a major environmental issue. The unique composition of such wastewater makes the use of traditional physicochemical techniques challenging.RESULTSIn this paper, titanium dioxide nanotube arrays/SnO2‐Sb2O3 (Ti‐NTA/SnO2‐Sb2O3) electrodes were prepared by anodizing–cathodizing and sol–gel method for the electrocatalytic degradation of printing and dyeing ROC. Organic matter removal under different situations was examined, and the best treatment parameters were identified.CONCLUSIONFollowing treatment, organic matter concentration dropped from 1600 to 50 mg L−1, or even less. The outstanding removal performance of the Ti‐NTA/SnO2‐Sb2O3 electrode was validated by full‐scan ultraviolet spectra, gas chromatography–mass spectrometry and three‐dimensional fluorescence. Evaluation of the dissolved heavy metals and halogenated degradation process byproducts revealed that the electrocatalytic membranes were environmentally safe. These findings highlight the enormous potential of electrocatalytic membranes for the treatment of high‐salt ROC when equipped with a Ti‐NTA/SnO2‐Sb2O3 electrode. © 2024 Society of Chemical Industry (SCI).

Cost-Effective Salt Harvesting: Efficient and Sustainable Production through Technological Innovation

Maximizing the quantity, quality, and cost-efficiency of salt production requires innovative approaches. This study presents a novel geo-membrane (GM)-based salt production technique that significantly improves salt yield and quality for Indian salt producers. The GM method is simple to implement across various salt production facilities, requiring only basic equipment. Compared to traditional methods, statistical analyses demonstrate substantial improvements in both the quantity and quality of salt produced with the GM method. The process enhances salt purity by 12–15%, reduces production costs by 15-20%, and prevents brine leakage, optimizing solar energy utilization in crystallization ponds. Keywords: salt production, geo-membrane, salt crystallization pond, cost-efficiency,sustainability

Modeling High Concentration Bisalt-in-Sulfolane Electrolytes and the Observation of Ligand-Bridged Cation-Pair Complexes.

Despite the abundance of sodium over lithium in Earth's crust and the copious amounts of expensive lithium salt required to make Li-ion high-concentration electrolytes (HCEs), studies of HCEs made from sodium salts remain sparse. A comparative molecular-level study of Li- and Na-ion HCEs and mixed cation or bisalt HCEs in an organic solvent is missing. To fill this gap, we studied model HCEs of pure and mixed Li and Na salts of bis(fluorosulfonyl)amide (FSI) in sulfolane using a confluence of classical molecular dynamics (MD), ab initio MD (AIMD) simulations, and quantum chemical cluster calculations. While Li-ion HCEs display transport properties superior to those of Na-ion HCEs, the latter's performance can be considerably improved by replacing even 25% of Na-ions with Li-ions. While the effects of doping are largely systemic, a larger sensitivity of the identity of solvation shells of Li-ions to the Li-content of the HCE is observed; in contrast, those of Na-ions are more oblivious to it. Fascinating ligand-bridged, short-distance cation pairs observed in the classical MD simulations are confirmed using density functional theory-based AIMD simulations. Quantum chemical calculations in the gas phase reveal the thermodynamic stability of such cation pairs complexed with multiple anions and solvent molecules.

Application of salt-assisted liquid extraction in bioanalytical methods

This review provides a comprehensive analysis of bioanalytical methods employed for the quantification of drug molecules in various biological matrices, including human plasma, urine, breast milk, and mouse plasma. The study not only examines traditional sample preparation techniques such as protein precipitation (PP), liquid-liquid extraction (LLE), and solid-phase extraction (SPE), but also delves into the relatively new and innovative salting-assisted liquid-liquid extraction (SALLE). It offers a thorough comparison of analytical methods utilizing SALLE, focusing on key parameters such as analysis time, calibration range, and the type and quantity of salts and organic solvents used. This review aims to serve as an essential resource for researchers and practitioners in selecting the most suitable bioanalytical methods for pharmacokinetic studies and drug monitoring, ultimately enhancing data quality and analytical efficiency in both clinical and research settings.

Integrating Umpolung and CO2 Shuttling Strategies for the Synthesis of 12C- and 13C-α-Ketoacids from Aldehydes.

The direct carboxylation of aldehydes with CO2 is rare due to the polarity mismatch between these two electrophilic substrates. To address this challenge, we propose a sequential approach for synthesizing α-ketoacids from commercially available aldehydes by integrating umpolung and CO2 shuttling strategies. This transition metal-free shuttle carboxylation method enables the transfer of CO2 from triphenylacetic acid potassium salt to thioacetal, eliminating the need for handling pressurized CO2 gas or using specialized equipment, while also enhancing the reaction's functional group tolerance. Furthermore, the use of stoichiometric or slightly excess amounts of triphenylacetic acid potassium salt as a formal CO2 donor makes it suitable for complete 13C labeling of α-ketoacids.

Barriers and enablers to salt intake reduction in Australian adults with high blood pressure.

High dietary salt intake is a known risk factor for hypertension. However, Australians continue to consume excessive amounts of salt. The purpose of this study was to identify barriers, enablers and strategies to reduce salt in a sample of Australian adults with hypertension. This was a qualitative study. Participants were asked a set of open-ended questions during focus groups conducted between October 2020 and April 2021. Sessions were recorded and transcribed. Using an inductive approach, the transcript data from the focus groups were thematically analysed. This involved checking accuracy, becoming familiar with the data, coding responses based on questions, identifying themes through common patterns and validating themes by grouping similar questions that represented the data and study aim effectively. Thirty-one adults (55 % females) with high blood pressure participated in the focus group discussions. Participants demonstrated good knowledge of high blood pressure risk factors but lacked an understanding of recommended salt intake levels and sources of hidden salt. Challenges in reducing salt intake included the limited availability of low-salt commercial foods. Participants suggested improved food labelling and the use of technology-based interventions to promote healthier choices. Findings highlight the need for behavioural interventions, policy reforms and collaborations between the government, food industries and health organisations to address high salt intake in the population.

Improving supercapacitor performance with novel potato starch-PVA solid polymer electrolyte blend modified by sodium perchlorate-glycerol additives

The synthesis and analysis of Solid Polymer Electrolytes (SPEs) derived from a blend of Potato Starch and Poly Vinyl Alcohol (PS-PVA), enhanced with Sodium perchlorate salt (NaClO4) and Glycerol (GCL) are explored in this work. Our focus is on their suitability for Electrical Double-Layer Capacitor (EDLC) devices. GCL, a non-toxic substance, served as the plasticizer, and sodium perchlorate was incorporated to enhance the ionic conductivity of the SPE film. The conductivity at room temperature for pure PS-PVA blend, in the absence of salt and GCL, was found to be 4.16 × 10−8 S cm−1. Upon adding an optimized quantity of NaClO4 salt, the conductivity increased to 1.02 × 10−5 S cm−1. Subsequent plasticization of the salt-polymer blend with GCL induced NaClO4 dissociation, further augmenting the conductivity by one order of magnitude. A conductivity value of 10.35 × 10−5 S cm−1 was achieved for the film with 30 wt% GCL. Morphological, electrical, and structural analyses revealed that synthesized polymer films exhibited favorable characteristics. The suitability of these electrolytes for Electric Double-Layer Capacitors (EDLC) was studied using electrochemical characterizations and cycling tests for 2000 cycles. The findings demonstrate their potential for use in energy storage devices, showcasing excellent performance in specific capacitance, energy, and power densities.

Semi-continuous cultivation of microalgae to treat coal mine effluent in pilot scale: Nutrient removal, biodesalination and fatty acid composition analysis

Coal excavation is associated with discharge of an enormous amount of mine water rich in salt and trace metal ions, which require efficient treatment before use. Considering the potentiality of microalgae for high salt tolerance, salt removal and metallic pollutant removal from aqueous system, present study focuses semi-continuous cultivation of candidate microalgae Chlorella pyrenoidosa (NCIM 2738) in bubble column reactor (BCR) and open raceway pond (ORP) for nutrient supplemented coal mine effluent (NSCME) treatment. In between different hydraulic retention times (HRTs), HRT 6 d provide maximum average biomass productivity of 950 mg L−1 d−1 in BCR and 728.4 mg L−1 d−1 in ORP. HRT 9 d facilitates a maximum lipid content of 1.8 g L ̶ 1 in BCR and 1.4 g L ̶ 1 in ORP. Further, HRT 9 d had the maximum COD removal efficiency (96.5 % in BCR and 94.2 % in ORP) and maximum salinity removal efficiency (93 % in BCR and 92 % in ORP). Fatty acid methyl esters (FAME) characterization highlighted potential biodiesel applicability with cetane number (CN) of 53.94. Energy dispersive X-ray spectroscopy (EDS) revealed an excess amount of salt and metal ions deposition on the surface of harvested microalgae samples. Outdoor large-scale C. pyrenoidosa cultivation can be integrated with coal mine closure plans to meet sustainable development goals (SDGs) 6, 7 and 13.

Effect of educational intervention based on the theory of planned behavior (TPB) on amount of salt intake in pregnant women with PreHypertension

BackgroundPrehypertension is one of the common disorders during pregnancy. Reducing salt intake is among the best cost-effective interventions to reduce the risk of hypertension. The present study aimed to explore the effect of an educational intervention based on the Theory of Planned Behavior (TPB) on amount of salt consumed by prehypertensive pregnant women.MethodsThe present quasi-experimental study was conducted in 2022 on 61 prehypertensive pregnant women visiting the Comprehensive Health Services Centers in Birjand, Iran. Pregnant women were selected through a convenience sampling method and randomly assigned to intervention and control groups. A blood pressure test and a 24-hour urine test were taken in 3 stages (before, immediately after, and one month after the intervention). A reliable and valid questionnaire based on the TPB was used to measure the cognitive variables. The intervention program included three training sessions based on the TPB held on an online platform (WhatsApp social network). Data were analyzed using repeated measures ANOVA and longitudinal marginal model with the GEE approach in SPSS19. The significance level for all statistical tests was set at p < 0 0.05.ResultsAfter intervention, the mean score of perceived behavioral control (p = 0.02), intention (p = 0.004), and salt consumption behavior (p = 0.03) increased significantly in the intervention group, and the mean score of systolic blood pressure (p < 0.001) and diastolic blood pressure (P < 0.01) decreased significantly in this group. In the control group, a statistically significant difference was observed in the systolic and diastolic blood pressure of the subjects (p < 0.01). However, the score of attitude, subjective norms, perceived behavioral control, intention, salt consumption behavior and the daily salt intake did not show a statistically significant difference over time (P < 0.05).ConclusionThe present findings showed that the perceived behavioral control, intention, behavior, systolic and diastolic blood pressure can be modifiable variables to improve the amount of salt consumed by pre-hypertensive pregnant women. Therefore, we recommend that the present model be used to develop interventions to improve health indicators in pregnant women as a highly susceptible group in society.

Preconcentration of Cinnamic Acid Derivatives in Traditional Chinese Medicines by an Effective Dispersive Liquid-Liquid Microextraction Based on a Hydrophobic Deep Eutectic Solvent.

A dispersive liquid-liquid microextraction based on hydrophobic deep eutectic solvent (hDES) was developed for the extraction and quantification of four cinnamic acid derivatives in traditional Chinese medicines coupled with high-performance liquid chromatography-ultraviolet detection. In this method, a hDES (tetrabutylammonium chloride-hexanoic acid, molar ratio of 1:2) was prepared as the extractant. It only took 15 s to handle multiple samples simultaneously by hand-assisted dispersion. The use of a narrow-bore tube reduced the amount of the hydrophobic extractant with easier recovery. The approach was influenced by several key parameters, including the composition and consumption of the DES, sample phase pH, salt amount, extraction time, and centrifugation time, all of which had been investigated and optimized. Moreover, the formation of the DES was characterized by Fourier-transform infrared spectroscopy and differential scanning calorimetry. Under the optimal conditions, enrichment factors of the target analytes ranged from 135 to 220. Satisfactory linearities (r ≥ 0.9977), detection limits (0.2-0.4ng/mL), precision (<8.5%), and accuracy (recoveries: 90.0%-104.6%) were obtained. The method has been successfully applied to the simultaneous extraction and preconcentration of four cinnamic acid derivatives in Chinese medicinal samples with rapidness, high efficiency, and convenience.

Exploration of supramolecular solvent-based microextraction for crystal violet detecting in water samples

This approach highlights the advantages of supramolecular solvents in a new microextraction model. The distinct properties and behavior of this supramolecular solvent provide enhanced extraction capabilities for detecting crystal violet (CV) in water samples. The methodical experimentation was executed to optimize the critical process parameters, providing maximum efficiency of crystal violet extraction at optimal conditions with pH set at 2.7, 186 μL of extraction solvent, extraction time of 3.5 min, and a salt amount of 3.1 % w/v, yielding the best results. Analytical data from extraction experiments under these optimal conditions demonstrated a high extraction percentage. The extraction model exhibited a linear response within the range of 10–800 ng mL−1 of crystal violet, with a detection limit of 2 ng mL−1. This model enables the measurement of CV in water samples with recovery rates exceeding 97 %, offering a straightforward and accessible approach for analysis.

Characterization and Classifications of Saline/Sodic Soils of Ambo Area of Irrigated Farm Land in Golina Watershed in Raya Valley, Amhara Region, Ethiopia

All soils are known to contain a certain amount of soluble salts and exchangeable sodium, magnesium, potassium, and calcium. However, excessive enrichment of any one of them can interfere with many soil processes, including plant growth, and the effects depend on the degree of enrichment and the type of plant. Therefore, the objective of this study was to characterize the salt-affected soils of the Ambo area for irrigated farmlands in the Golina Watershed in Raya Kobo Woreda, Amhara region. One profile was excavated from an irrigated field to carry out this activity. One profile was excavated from the irrigated field to conduct this activity. Ten soil samples were taken from the soil profile at 2 m depth at 20 cm depth intervals. The samples were analyzed for several soil physical properties, including soil pH, soluble cations and anions, soluble salts (electrical conductivity, EC), exchangeable cations (Ca, Mg, Na, K), total nitrogen, organic carbon, soluble phosphorus, percent exchangeable sodium, sodium absorption, and soil physical properties (soil color, texture, bulk density, and soil porosity). Chemical properties were also analyzed. The analysis showed that the irrigated farmland soils had a pH of 7.6 to 8.8, electrical conductivity of 1.3 to 14 dsm-1, organic carbon of 0.3 to 1.2%, total nitrogen of 0.11 to 0.35%, soluble phosphorus of 24 to 41.4 mg kg-1, and cation exchange capacity of 50.3 to 65.5 cmol(+) kg-1. The distribution of exchangeable calcium was not consistent across the soil profiles of the irrigated farmlands. In general, the top layer of soil at both sites (because of its agricultural use) was considered for EC, ESP, and pH values. The irrigated farmland soils were classified as saline soils.

Synthesis of Starfish-Shaped ZnS Nanostructures by Hydrothermal Method and Their Electrochemical Sensing of Dopamine.

Introduction Dopamine serves an essential function as a neurotransmitter, influencing the regulation of movement, cognitive processes, and emotional states. The identification of abnormal dopamine levels is critical for clinical diagnoses and scientific research, given its links to various disorders, including depression, schizophrenia, and Parkinson's disease. The distinctive electrochemical characteristics, stability, and broad bandgap of zinc sulfide (ZnS) nanostructures render them particularly fascinating. The hydrothermal method is recognized as an effective and economical approach for the fabrication of ZnS nanostructures, exhibiting a range of morphologies. Utilizing this method to create ZnS nanostructures leads to the formation of structures characterized by extensive surface areas, hierarchical designs, and improved electrochemical properties. Aim The objective is to examine the electrochemical characteristics of ZnS starfish-shaped nanostructures produced through the hydrothermal technique and to assess their viability as a sensing platform for dopamine detection. Materials and methods To synthesize ZnS nanoflowers, stoichiometric amounts of transition metal salts were prepared: 10 mM of Zn(NO3)2•3H2O and 30 mM of sodium thiosulfate (Na2S2O3•5H2O) were dissolved in 30 mL of deionized water and stirred for 20 minutes. The solutions were then combined and transferred into a 100 mL Teflon autoclave reactor, which was heated at 200 °C for 12 hours in a furnace. This process utilized the hydrothermal technique to produce the desired ZnS nanoflowers. Result The crystalline arrangement of ZnS was validated by X-ray diffraction (XRD) analysis, aligning with the Joint Committee on Powder Diffraction Standards (JCPDS). Moreover, field emission scanning electron microscopy (FE-SEM) illustrated the particle morphology of ZnS, showing a range between 200 and 500 nm size. Additionally, the cyclic voltammetry results indicated that the modified electrode produced a greater current response than the bare electrode, highlighting its improved sensitivity to dopamine molecules. Conclusion ZnSnanoparticles were synthesized via a hydrothermal method and characterized using XRDand FE-SEM. These nanoparticles were used for electrochemical dopamine detection, showing potential for advanced sensing platforms. Integrating ZnS into microfluidic devices enables real-time dopamine monitoring, opening new possibilities for healthcare and neurochemical research. Exploring surface engineering techniques could further enhance the electrochemical performance of ZnS-based sensors.

Survey on the salt usage among Fish Cracker (Keropok lekor) manufacturers in several districts of Kuala Terengganu, Malaysia

Fish crackers (keropok lekor) are known for their tastiness. Although rich in protein and iodine, it contains a high amount of salt or sodium. Therefore, this study aimed to determine the manufacturers’ practice in the preparation of keropok lekor, perception and challenges concerning salt usage, and motivation to reduce salt content. This study also aimed to estimate the sodium content in keropok lekor. Seven manufacturers of keropok lekor in Terengganu were interviewed either face-to-face or online to obtain relevant information. All interviews were recorded, transcribed, and analyzed based on a thematic analysis framework. The recipes of keropok lekor were analyzed using the Nutritionist Pro software to determine the nutritional and sodium content, calculated based on the Malaysian and ASEAN Food Composition Tables. Based on the interviews, most manufacturers (90%) supported the effort to reduce salt in keropok lekor. However, the effort was met with several challenges, such as customer acceptance and negative perception of the taste, decreased sales, and increased material costs. The enabling factors include maintaining the original flavor of keropok lekor, customer requests, marketing opportunities, and the availability of salt substitutes. Support for marketing and financial technology know-how is also necessary. An estimate of 606.43 mg/100g of sodium content in keropok lekor was obtained in this study, which was mainly derived from the usage of sodium chloride and monosodium glutamate (MSG) during the preparation. This study revealed the high salt content in keropok lekor due to the addition of salt and seasonings. There is a potential to reduce salt content in keropok lekor with appropriate support provided to the manufacturers. Nevertheless, further research is needed to produce keropok lekor with reduced salt content, improved sensory, and enhanced microbial and physicochemical characteristics, which can improve customer perception.

An Investigation of the Factors Influencing the High Temperature Rheology of Polymers

Introduction: Nowadays, polymers, as an important application material in drilling engineering, have obvious advantages in solving the rock-carrying problem at the bottom of deep wells, and improving the drilling speed due to their excellent viscosity enhancement effect. Method: In this study, the effects of polymer type, concentration, shear time, electrolyte, and clay on the rheological properties of polymer solutions at high temperature and high pressure were investigated using a Fann 50SL rheometer. The experimental results showed that, except for the polymer additive amount and clay, the increase in shear time and the amount of salt both led to a decrease in the viscosity of the polymer solution, with 190°C as the critical temperature above which the viscosity decreased significantly. Results: The polymer solution containing formate showed higher viscosity retention during heating and then cooling compared to chlorides. The presence of clay enhances the reticulation of polymer molecules in the blend, which facilitates the carrying of rock cuttings at high temperatures. In addition, regression analyses showed that the increase in temperature resulted in an enhanced tendency for the polymer solution to evolve from a pseudoplastic to a Newtonian type. Conclusion: This research provides theoretical basis and data support for developing high-temperature polymers and formulating high-temperature drilling fluid systems.

State Regulation of the Salt Industry on the Astrakhan Salt Lakes in the First Half of the 19th Century

Introduction. Based on the materials of the State Archive of the Astrakhan region, which were first introduced into scientific circulation, the issues of salt extraction by the Kalmyks and its transportation by state peasants and Tatars on the Astrakhan salt lakes in the first half of the 19th century are highlighted. Methods and materials. The research is based on both published and unpublished sources. Analysis. The role of the state in organizing the selection of salt lakes, determining the amount of salt extracted and its transportation, hiring labor, remuneration, catering, and supply issues is analyzed. It was revealed that in the Astrakhan province, in addition to state-owned salt extraction, work was carried out on lakes owned by private salt producers, with the mandatory conclusion of a contract with the Astrakhan Salt Board and their payment of excise duty. Attention is focused on the rules developed by the Astrakhan Commission of Kalmyk Affairs for Kalmyks who were employed in government and private jobs. Results. Increased centralization and regulation of the organization of the salt business on the salt lakes of the Astrakhan province by the state was expressed in the identification of specific lakes for salt extraction, the organization of labor for its extraction, storage, and transportation, the establishment of wages, the price of sold salt, and the attraction of salt industrialists. It was aimed at increasing the Treasury’s income from the extraction and sale of Astrakhan salt. The contribution of the authors. Identification, collection, and processing of documents from the State Archive of the Astrakhan region were carried out by M.M. Khairlapova; preparation of sections of the article; and analysis of the process of organizing the salt industry by T.V. Yudina.