Solution Composition Research Articles

The Development and Analysis of a Preliminary Electrodialysis Process for the Purification of Complex Lithium Solutions for the Production of Li2CO3 and LiOH

Direct lithium extraction (DLE) is emerging as a promising alternative to brine extraction although it requires further processing to obtain high-quality products suitable for various applications. This study focused on developing a process to concentrate and purify complex LiCl solutions obtained through direct lithium extraction (DLE). Two different chemical compositions of complex LiCl solutions were used, dividing the study into three stages. In the first part, lithium was concentrated to 1% by mass by evaporation. In the second, electrodialysis was used to alkalinize the LiCl solution and remove magnesium and calcium impurities under different current densities. The best results obtained were magnesium and calcium removals of 99.8% and 98.0%, respectively, and lithium recoveries of 99% and 96%. In the third stage, the selectivity of two different commercial cationic membranes (Nafion 117 and Neosepta CMS) was evaluated to separate Li+, K+, and Na+ cations under different current densities and volumetric flow rates. The Neosepta CMS membrane demonstrated higher lithium recovery. This study evaluated the quality of the purified lithium-rich solution and its potential use both in the production of Li2CO3 as well as in the electrochemical production of LiOH.

Implantation of web-like cellulose nanofibrils on electrospun fibrous membrane for boosting filtration performance.

Air pollution such as particulate matter is always a serious threat to public health, thus many disposable and degradable air filters were designed to deal with this severe challenge avoiding the secondary pollution after discarding. Herein, inspired by the natural spider web structure, a hierarchical porous composite fibrous membrane containing web-like cellulose nanofibrils (CNF) was developed. The implanted porous CNF membranes with web-like among the inter-fiber voids of electrospun poly(ethylene-co-viny alcohol) fibrous membrane were realized via a layer-by-layer (LBL) method followed by an elevated-temperature drying, which exhibit a smaller diameter with one or two orders of magnitude reduction comparing with the substrate fibers. The morphology of implanted CNF membranes can be regulated by changing the CNF dispersion concentration, PH, solution composition as well as the LBL times. The addition of a small amount of isopropyl alcohol to the CNF solution can efficiently facilitate the implantation of web-like CNF on substrate, resulting in both improvements on the mechanical properties and filtration capacity. The result shows that the implanted web-like CNF of as-prepared composite membrane can enhance the PM 0.3 capture ability (reaching 96.8%) while not surge its pressure drop (225.7Pa) exceeding N95 standard. This work presents a new design and fabrication of CNF-based filter materials directly without using freeze drying, which can not only provide a fully or partially biodegradable air filter but also give encouragement to explore new filters efficiently.

Application of Composite Soaking Solution in Fillet Storage and Caco-2 Cell Antioxidant Repair

The inhibitory effect of compound soaking solution on the quality deterioration of fish fillets during storage and its repair effect on a cell oxidative damage model were investigated. Water holding capacity, cooking loss, thawing loss, thiobarbituric acid and sensory evaluation were used to verify that the composite soaking solution could improve the water loss and quality deterioration of fillets during frozen storage. At 180 d, water holding capacity was increased by 4.59% in the compound soaking solution group compared with the control. Cooking loss decreased by 6.47%, and thawing loss decreased by 13.06% (p < 0.05). The TBA value was reduced by 50%, and the degree of lipid oxidation was lower (p < 0.05). The results of the microstructure analysis showed that the tissue structure of fillets treated by the compound soaking solution was more orderly. The oxidative damage model of cells was achieved by soaking in treated fish fillet digestive juice, which inhibited the increase in reactive oxygen species content, maintained the integrity of the cell structure, and increased cell viability by 32.24% (p < 0.05). Compound soaking solution treatment could inhibit the quality deterioration of fish fillets during storage, and the digestive solution of fish fillets could improve the oxidative stress injury of Caco-2 cells induced by H2O2.

Effectiveness of the use of a plant immunostimulator for feline bordetelliosis

In veterinary practice, veterinary specialists solve the important problem of the occurrence and development of immunodeficiency during respiratory infectious pathology in cats with the help of biologically active additives, probiotics, enzymes, immunostimulators and vitamins. Interferons are one of the most popular in use from the list of endogenous immunomodulators. But often the disadvantage of purely immunomodulatory drugs is their difficult transfer and the presence of a negative effect on the body of domestic animals. Therefore, an alternative to interferons in order to increase the immune resistance of the body and improve the well-being of cats is the search, development and use of preparations based on plant raw materials. The article presents the results of the study of the effectiveness of the herbal immunomodulator in comparison with the interferon drug "Anfluron", which was used in two complex treatment schemes for cats suffering from Bodetheliosis infection. To increase the immune resistance of cats for bordeteliosis, an aqueous solution of a medicinal composition based on the Rhodiola rosea root, Oplopanax root, Rozae fruits, Urtica dioica, Crataegus fruits, Hypericum perforatum fruits was used in an effective ratio of 1:1:1:0.8:0.8:0.5. As a result of the use of the specified herbal preparation, a positive trend in the reduction of the manifestation of clinical signs in sick cats was established from the 6th day of use with a direct correlation of the decrease in the manifestation of clinical signs in sick animals treated with a classic interferon drug. As a result of the application of complex therapeutic regimens using various immunomodulatory drugs, a significant alignment of hematological indicators to the physiological norm was noted on the 10th and 14th day of treatment in animals of both study groups. The results obtained in the comparative aspect showed that the proposed herbal preparation has an immunostimulating effect, improves the general condition and can be used in the complex treatment of cats with bordetelliosis.

MACROCOMPONENT COMPOSITION AND GENESIS OF PORE SOLUTIONS IN HYDROTHERMAL CLAYS OF THE PAUZHETKA GEOTHERMAL SYSTEM (southern Kamchatka)

We have studied the macrocomponent composition of pore solutions in hydrothermal clays forming extended thick strata in the thermal fields of the Pauzhetka geothermal system. Two zones have been identified in the vertical sections of the clay strata, which differ in the physicochemical parameters, composition, and formation conditions of pore solutions. It is shown that the pH of the solutions plays a crucial role in the change of their macrocomponent composition with depth. The conclusion is drawn that the pore solutions resulted from the direct impact of deep-level infiltrating thermal waters on the matrix of hydrothermal clays, which led to the redistribution of elements between the rock and the contact solution. Along with the general regularities, we have established significantly different conditions of formation of pore solutions in the Upper Pauzhetka and East Pauzhetka thermal fields, which is due to the different geologic positions and hydrogeochemical regimes of these fields.

A Composite Vase Solution Using Silicon (Si) and Other Preservatives Improved the Vase Quality of Cut Lily (Lilium ‘Siberia’) Flowers

A Composite Vase Solution Using Silicon (Si) and Other Preservatives Improved the Vase Quality of Cut Lily (Lilium ‘Siberia’) Flowers

Formation of a Novel Antagonistic Bacterial Combination to Enhance Biocontrol for Cucumber Fusarium Wilt.

Paenibacillus polymyxa strain PJH16, isolated and tested by our team, suppresses cucumber Fusarium wilt as an efficient biocontrol agent. For further investigation, the strain has been combined with two other Bacillus strains (Bacillus velezensis VJH504 and Bacillus subtilis JNF2) to enhance biocontrol ability, which formed high-efficiency microbial agents in the current study. The methodological target taken is based on achieving the optimal growth conditions of the combined microbial agents; hence, the medium composition and culture conditions were optimized through a single-factor test, orthogonal test and response surface methodology. Following this, the effectiveness of the microbial combination was assessed through pot experiments, which provided a theoretical foundation for the synthesis of microbial flora to significantly control cucumber Fusarium wilt. The results showed excellent compatibility, proving suitable for the proliferation and growth of Paenibacillus polymyxa PJH16, Bacillus velezensis VJH504, and Bacillus subtilis JNF2 strains together, specifically, when the inoculation amounts were adjusted to 4% of each. Using the single-factor test and orthogonal test analysis, the optimum composition of culture medium for the composite strain was identified as 3% glucose as the optimal carbon source, 2% yeast extract powder as the preferred nitrogen source, and 1% dipotassium hydrogen phosphate as the most suitable inorganic salt. Furthermore, the optical density (OD600) of the composite strain solution reached its highest level at 3.16 under the following culture conditions: inoculation volume of 200 µL, 171 rpm culture speed, 21.6 h culture time, 30 °C cultural temperature, and an initial pH of 7.0. The pot experiment demonstrated that the mixed bacterial solution achieved a relative control efficacy of 93.4% against cucumber Fusarium wilt, which was significantly superior to that of single- strain or pesticide treatment, and also promoted cucumber growth. In summary, the microbial flora synthesized by the three Bacillus strains displayed a high bacterial concentration, following the optimization of culture conditions, and exerted remarkable control and growth-promoting effects on cucumber Fusarium wilt. This finding holds great significance for future developments of composite microbial agents.

Antimicrobial Efficacy of Five Wound Irrigation Solutions in the Periprosthetic Joint Infection Microenvironment In Vitro and Ex Vivo.

Background/Objectives: Periprosthetic joint infections (PJI) are difficult to treat due to biofilm formation on implant surfaces and the surrounding tissue, often requiring removal or exchange of prostheses along with long-lasting antibiotic treatment. Antiseptic irrigation during revision surgery might decrease bacterial biofilm load and thereby improve treatment success. This in vitro study investigated and compared the effect of five advanced wound irrigation solutions to reduce bacterial burden in the PJI microenvironment. Methods: We treated in vitro biofilms grown on titanium alloy implant discs with clinical bacterial strains isolated from patients with PJIs, as well as abscess communities in a plasma-supplemented collagen matrix. The biofilms were exposed for 1 min to the following wound irrigation solutions: Preventia®, Prontosan®, Granudacyn®, ActiMaris® forte ('Actimaris'), and Octenilin®. We measured the bacterial reduction of these irrigation solutions compared to Ringer-Lactate and to the strong bactericidal but not approved Betaseptic solution. Additionally, ex vivo free-floating bacteria isolated directly from clinical sonication fluids were treated in the same way, and regrowth or lack of regrowth was recorded as the outcome. Results: Irrigation solutions demonstrated variable efficacy. The mean CFU log10 reduction was as follows: Octenilin, 3.07, Preventia, 1.17, Actimaris, 1.11, Prontosan, 1.03, and Granudacyn, 0.61. For SACs, the reduction was: Actimaris, 8.27, Octenilin, 0.58, Prontosan, 0.56, Preventia, 0.35, and Granudacyn, 0.24. Conclusions: All solutions achieved complete bacterial eradication in all tested ex vivo sonication fluids, except Granudacyn, which was ineffective in 33% of the samples (2 out of 6). Advanced wound irrigation solutions have the potential to reduce bacterial burden in the PJI microenvironment during revision surgery. However, their efficacy varies depending on bacterial species, growth state, and the composition of the irrigation solution. This underscores the importance of considering these factors when developing future PJI-specific irrigation solutions.

Integrated removal of chromium, lead, and cadmium using nano-zero-valent iron-supported biochar: Mechanistic insights and eco-toxicity assessment.

The contamination of water and soil by heavy metals (HMs) is a global issue that should be given much more concern. Modified nano-zero-valent iron (nZVI) composites offer an effective strategy for HMs remediation, but few studies have focused on removing coexisting HMs and the eco-toxicity of the composite. In this study, corn straw biochar-supported nZVI composites (nZVI-BC) were synthesized, characterized and used for the removal of Cr6 +, Pb2+, and Cd2+ in single and multi-system at different composites dosages, metal concentrations, and solution pH. This study indicated that the composites exhibited enhanced removal capacities for Cr6+, Pb2+, and Cd2+ (respectively 82.24, 737.2, and 545.28 mg g-1), which were considerably superior to those observed with the sole application of biochar (0.05, 89.88, and 108.49 mg g-1) and nZVI (39.8, 297.35, and 191.02 mg g-1). Results of the remediation application of the composites to multi-metal systems revealed that intricate interplay existed between coexisting HMs, which hindered the simultaneous removal effect. The coexistence of Cr6+ and Cd2+ decreased both removal efficiencies by 58.16 % and 14.06 % at high Cr6+ levels, respectively, while the coexistence of Cd2+ and Pb2+ resulted in a decrease in Cd2+ removal efficiency by 14.3 %. An in-depth characterization of the underlying adsorption mechanism was performed by using kinetic and isotherms models such as Pseudo-first-order, Pseudo-second-order, Langmuir and Freundlich, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis. Each HM exhibited a distinct adsorption mechanism. The primary removal processes for Cr6+ and Pb2+ involved adsorption, reduction, and precipitation, whereas Cd2+ was mainly removed by adsorption and precipitation. Eco-toxicity experiments revealed that nZVI-BC enhanced pak choi (Brassica rapa L.) seeds germination (13.32, 17.22, and 23.33 %) and vigor indexes (1.22, 1.44, and 1.15) under Cr6+, Pb2+, and Cd2+ contamination, respectively. Nevertheless, an observed shift in toxicity occurred when the composites dosage for Cr6+, Pb2+, and Cd2+ exceeded 2, 4, and 4 g L-1, respectively, thereby instigating adverse effects on the early stages of plant growth. This work elucidates the removal mechanism and intricate reactions between co-existing HMs, highlighting the potential of nZVI-BC as a remediation strategy for HMs contamination.

A-site composition tuning in methylammonium-based metal halide perovskite colloidal nanocrystals

Utilizing the soft-lattice nature of metal halide perovskites, we employ post-synthetic cross-ion exchange to synthesize a series of narrow band-gap colloidal nanocrystals of methylammonium-based lead iodide solid solutions of composition...

Self-limiting selective phase separation of graphene oxide and polymer composite solution.

Homogeneous mixtures undergo phase separation to generate rich heterogeneous structures as well as enable complex physiological activity and delicate design of artificial materials. Beyond free space, the strong coupling between migrating components and spatial confinement plays a crucial role in determining the essential spatial compartment of phase separation, warranting further continuous exploration. Herein, we report the selective phase separation (SPS) behavior of polymers under a mobile two-dimensional (2D) confinement by graphene oxide (GO) sheets. The selection of a poor solvent triggers the occurrence of SPS in a homogeneous solution of GO and polymers. We reveal that the self-limiting spatial confinement of GO sheets leads to the migration of polymers to form independent and continuous phase in 2D confinement. We examine the quantitative rule of size and continuity of polymer phases in correlation with solvent properties and solute constitutes. The observed SPS allows the facile generation of heterogenous nanostructures in GO/polymer composites. We initiate a SPS wet-spinning to fabricate radial heterogenous fibrous graphene composite fibers with ultrahigh elongation at break and superior flexibility. The observed SPS can inspire more exceptional phase separation behaviors under mobile 2D confinement and offers a facile method to delicately design 2D heterogeneous nanostructured materials.

THERMODYNAMIC AVAILABILITY OF PLANT NUTRITION FROM SOIL DEPENDING ON CHANGES IN WEATHER FACTORS IN THE DAILY CYCLE

The weather is one of the determining factors in crop productivity. The purpose of this publication is to experimentally confirm and highlight the mechanism of the emergence of the dynamics of pore solution’s chemical composition and its thermodynamic accessibility to plants during the interaction of black soil with thermodynamic weather factors in the daily cycle. It has been established that the dynamics of availability should be sought precisely in the daily cycle of soil interaction with the environment. The basis of experimental laboratory research was the thermodynamic hydrophysical method. Samples of typical light loamy black soil of undisturbed structure from the Obukhiv district of the Kyiv region were studied. The studies have found that the emergence of the dynamics of thermodynamic accessibility of the pore solution and its chemical composition is ensured by subordinate processes that occur in the soil under the influence of cyclic environmental factors - temperature, atmospheric pressure, and moisture saturation. During the laboratory experiments, reproducible dynamics of the chemical composition of the pore solution were obtained in the daily range of changes in the specified factors. It is likely that the formation of such dynamics in three cycles of desorption - sorption is provided by all five categories of soil absorption capacity. The chemical composition of the pore solution is functionally related to the heterogeneity parameter of soil environment, which is determined by the thermodynamic potential of moisture. Among the components of the chemical composition, the dynamics of the content of nitrate ions (NO3-), as one of the most important biogenic compounds, deserves an increased attention. The unique dynamics of NO3- content consists in its increase as the heterogeneity (desorption) of the soil (soil moisture) increases, approximately to the values of field capacity. This is explained by the specific behavior of these ions, which have a negative adsorption capacity (physical absorption capacity), between the two surfaces: solid particles-liquid and liquid-air, namely their concentration near the surface of separation in contact with the atmosphere. For structured soil with the presence of trapped air in macropores, nitrate ions are protected from leaching by the flow of moisture and are released into the pore solution in a volley when the macropores open, which is important for the conditions of nitrogen nutrition of plants. The conducted research outlines a whole section of thermodynamic research of soils with undisturbed structure, the implementation of which will result in parametric models for ensuring the production process of plants.

Electrodeposition of Corrosion Protective Zinc Films from Reverse Micellar Solutions

Abstract Electrodeposition of metallic zinc (Zn) from reverse micellar solutions of cetyltrimethylammonium bromide (CTAB) of different compositions was successfully performed using constant potential electrolysis on copper (Cu) substrate. Electrochemical behavior of ZnSO4 was investigated in reverse micellar solutions of CTAB on a glassy carbon (GC) electrode by cyclic voltammetric technique and the electroreduction of Zn(II) to Zn(0) was suggested to be an electrochemically irreversible diffusion controlled process. Morphology and microstructure of the electrodeposited Zn films onto a Cu substrate were examined by scanning electron microscopy, while elemental characterizations were carried out by energy dispersive X-ray spectroscopic method and X-ray diffraction technique. Electrodeposition of Zn from reverse micellar solutions occurred with definite homogeneous shapes whereas, inhomogeneous/random gross Zn deposition was obtained from aqueous system. Moreover, morphology of the electrodeposited Zn films obtained from reverse micellar solutions was found to be varied with the variation of composition of reverse micellar solutions of CTAB. The corrosion protective behavior of the electrodeposited Zn films evaluated through electrochemical impedance spectroscopy and potentiodynamic polarization techniques with 3.5 wt.% NaCl solution as corrosion media showed that Zn deposits obtained from reverse micellar solutions exhibited better corrosion protection behavior compared to that obtained from aqueous solution.

Prolonging neutrophil room temperature storage with clinically-approved solutions: Implications for granulocyte transfusion

Abstract Introduction Granulocyte concentrates (GC) are leukocyte preparations enriched in neutrophils that can potentially save neutropenic patients from life-threatening, antimicrobial-resistant infections. The main challenge of GC transfusions is preserving the viability and antimicrobial activity of neutrophils beyond 24 h to reduce the logistical burden on collection centers and increase the availability of this cell therapy. Thus, the aim of this study was to explore extending the ex vivo viability and antimicrobial activity of GC neutrophils up to 72 h with a unique combination of the clinically-approved additives Plasma-Lyte, SAGM, AS-3 and Alburex. Methods Neutrophils isolated from healthy donors were resuspended in autologous plasma (AP) at the same concentration as in GCs and diluted with various combinations of Plasma-Lyte, SAGM, AS-3 and/or Alburex with or without the addition of buffers, and stored at room temperature for up to 72 h. During storage, neutrophil viability, phagocytosis and intracellular reactive oxygen species production were measured by flow cytometry. Extracellular reactive oxygen species production was measured by spectrophotometry and chemotaxis by the number of calcein stained neutrophils that migrated towards the chemotactic peptide, N-Formyl-Met-Leu-Phe (fMLF). The same assays were performed on pooled, residual leukocyte units generated by the Reveos system, after storage in the additive combination that most effectively preserved the viability and function of isolated neutrophils. Results The additive combination that best performed in the majority of the assays contained Plasma-Lyte, buffers and AS-3. Neutrophil viability was preserved for a maximum of 48 h and phagocytosis of opsonized bacteria and reactive oxygen species production up to 72 h of storage at room temperature. In contrast, fMLF-induced chemotaxis decreased by 20 % after 24 h storage while extracellular reactive oxygen species production increased significantly within the same time period. Supplementing GCs prepared from pooled, residual leukocyte units with this storage solution after the standard 16-24 h processing period as per the blood center guidelines, did not significantly improve the preservation of neutrophil viability and function. Conclusion Our findings provide proof of concept that mixtures of clinically-approved additives can be tailored to significantly prolong the viability and function of freshly isolated neutrophils during room temperature storage. The unique additive composition of this storage solution that we developed for freshly isolated neutrophils, requires further optimization for use with pooled, residual leukocyte units as well as the time point at which the solution is added during processing to prolong the viability and functions of neutrophils in this blood product.

Эколого-географическая характеристика озера Пелёнкино (Ростовская область) по материалам ретроспективных и современных исследований

The physical and geographical characteristics and geological structure of Lake Pelenkino are described. During the analysis of the results of the satellite survey, it was found that the area, length and width of the water surface of the reservoir, as well as the length of the lake's shoreline, the elongation index, and the compactness of the lake vary significantly both by year and by season. It has been suggested that the water surface area and the chemical composition of the water are influenced by both the amount of precipitation and wind-driven effects in the Sea of Azov. The chemical composition of water and mud solution is prone to accumulation of an equivalent amount of Mg2+ relative to Ca2+ over time, which may be due, along with the influence of a hydrological factor, to a change in the physical and chemical equilibrium in the water-mud system. According to the description of the well cores, deposits up to a depth of about 15-35 cm are represented by silt (mud), which first turns into steel-gray clay of a semi-liquid consistency, and then to the bottom of the layer into denser clay. The physical and chemical parameters of the mud of Lake Pelenkino allow us to classify them as continental, silt, mineral, medium mineralized, slightly alkaline, slightly sulfide peloids. Lithological control was found for a set of parameters (pH, Eh, CH4, Ssulfide), which manifests itself in their synchronous change during the transition from silts to the bedrock sediments of the reservoir bed – steel-gray clays. The content of gross mercury in the mud and sediments of the lake does not exceed the threshold of the Low range of Exposure (EQL), equal to 0.15 micrograms/g of dry weight. The bottom sediments of the rivers of the Pelenkino Lake basin and its mud themselves are under anthropogenic influence, which primarily forms a low level of perfringence titer values and its virulence. The use of lake mud for therapeutic purposes without prior preparation is not recommended.

Assessment of the durability of hardening products of modified fly ash cement compositions

This work is devoted to the study of the durability of hardening products of modified gold-cement compositions. The influence of sulfate and carbonate additives of various origins on the kinetics of increasing the strength of artificialstone was studied.To reveal the mechanism of the processes of strength synthesis of the developed binder systems, their hydration products and the composition of new formations were studied using X-ray diffraction (XRD), differential thermal analysis(DTA) and electron microscopy.It was established that with simultaneous modification of the plasticized fly ash cement composition with sulfate and carbonate additives, the synthesis of strength is ensured due to the formation of hydration products in the composition atthe early stages of hardening of ettringite and its analogues containing carbonate and ferric components. It has been determined that the presence of hydrosulfoaluminate-type new formations in the hydration products and the presence of active mineral additives in its composition on the one hand, and on the other hand, the contact of cement stonewith the environment can cause the appearance of dangerous compounds (such as thaumasite) in hardening systems, the synthesis of which leads to the emergence of stresses in the structure of the material and its destruction. It has been established that as a result of the processes of isomorphic substitution, compounds of variable composition are formed, similar to solid solutions, due to which the strength of artificial stone is ensured in the later stages of hardening. On the other hand, the released sulfate ions can replace silicon groups in the tobermorite gel and form compounds similar to epistilbite (Ca6(Si(OH)6)3·(SO4)3·24H2O) (d=0.584; 0.399; 0.369; 0.354 nm). The strength indicators of artificial stone basedon modified fly ash cement binder compositions were investigated. It is associated with the directed formation of crystallochemically similar phases that can grow together, and the formation of artificial stone capable of structural and functional adaptation in various operating conditions will likely be due to the formation of solid solutions of hydrosulfoaluminocarbosilicate composition, hydrogarnet phases of the composition 3СаО·Al2O3·1,6SiO2·2,8H2O and modified calcium hydrosilicates of the epistilbite type Ca6(Si(OH)6)3·(SO4)3·24H2O) and scoutite (Са6Si6O18·2H2O·CaCO3). in the composition of new formations.

Novel 3D composite for efficient photocatalysis in environmental remediation

AbstractHighly porous, self-supported 3D interconnected network-based nanomaterials hold immense promise in revolutionizing the field of catalysis. These materials combine two critical features; a large accessible surface and an overall active surface that leads to substantial catalytic effects. In this study, we developed a novel class of 3D composite material composed of zinc oxide tetrapods (ZOT) and polyethylene glycol (PEG) polymer, specifically designed for photocatalysis. A polymer composite of ZOT with PEG has been synthesized with 2.5 wt.% ZOT powder mixed with a PEG solution forming a 3D electrode. A consistent composite solution was obtained using probe-sonication and its thick layers were deposited on various substrates using the spin coating technique which were subsequently characterized for optical, morphological, and structural properties. The catalytic response of the fabricated 3D composite was evaluated both in solution and thin film forms under UV exposure. The surface-engineered ZOT-PEG composites showed an excellent capability to degrade the methylene blue (MB) dye in different forms under UV and normal light, opening their potential scopes in environmental remediation.

Ecological and geochemical studies of clastic material from the Bureya landslide after cyclic freezing/thawing <i>in vitro</i>

The paper presents the results of experimental study (in vitro) of the transformation of clastic material (CM) sampled from a landslide body at the Bureya water reservoir. СM samples are considered as a model for assessing the influence of abiogenic and biogenic factors on the transformation (destruction, dissolution) of Si-containing minerals under various conditions of cyclic freezing/thawing, i. e., the dry sample; the samples placed in deionized water and in the presence of a solution of low molecular weight peptides. Freezing was carried out at a temperature of –18 °C, and thawing at a different temperature range (+4°C and +23°C). The elemental composition of aqueous solutions was determined by ICP-MS, and the microstructure of the CM surface was determined using scanning electron microscopy. As a result of 5 cycles after 7 days of freezing/thawing of CM samples in deionized water, the content of water-soluble forms of chemical elements (Fe, Ni, Cu, Zn, As, Mo, Ag, Cd, Tl, Bi, As) was below the detection limits of the device ( 0.001 µg/l). However, in the presence of a nutrient medium with peptone and a natural microbial consortium that retained its viability, the concentrations of a number of elements (Al, Ca, Mg, Fe, Mn, As, Hg) in the aquatic environment increased significantly. According to SEM images, a significant change in the microstructure of the surface of the samples CM occurred regardless of the thawing temperature when microorganisms were activated by low-molecular peptides. The formation of biofilms on the surface of CM grains was accompanied by the formation of various isomorphic microaggregates.

Some constructions for solving routing problems using decompositions and transformations of target sets

Issues related to solving the additive problem of sequential traversal of sets with precedence restrictions and cost functions that allow dependence on the list of tasks are considered. The basic method is a broadly understood dynamic programming (DP), supplemented in the case of problems of appreciable dimension by decompositions of the family of tasks and transformation of the parameters of the original problem. Possible applications are related, in particular, to the problem of tool control in figured sheet cutting of parts on CNC machines. In this problem, an important circumstance is taking into account the precedence conditions, which have, in particular, the following meaning: in the case of a part with holes, cutting of each of the internal contours (corresponding to the holes) should precede cutting of the external contour. The quality criterion itself in this problem, as a rule, is additive. Another type of constraints concerns avoiding thermal deformations of parts. When using the approach with penalties for violating the conditions associated with effective heat dissipation during cutting, cost functions arise that allow dependence on the list of tasks completed to date. Note that in another applied problem, namely, in the problem of dismantling radiation hazardous objects, cost functions arise with dependence on the list of tasks that have not been completed at the moment (and, consequently, concern the objects that have not been dismantled). As a result, we arrive at a very general problem with precedence constraints and cost functions with dependence on the list of tasks. The decomposition applied in the case of a noticeable dimensionality with subsequent implementation of the DP requires, on the one hand, the development of clustering methods, and, on the other, the construction of an adequate structure for distributing global precedence conditions among clusters. In the theoretical part of the work, the case of two clusters is discussed, which makes it possible to cover with a single scheme a number of practically interesting problems of a range (in terms of dimensionality) type. An algorithm for constructing a composite solution is indicated, including a stage of clustering training based on a greedy algorithm. This “composite” algorithm is implemented on a PC; a computational experiment was carried out.

Black spruce boreal forest soil solution inorganic nitrogen is highly resilient to 20 years of elevated nitrogen deposition

Soil solution is the liquid phase of soil containing nutrients that are essential for vegetation’s health and growth. As such, soil solution chemistry is directly related to nutrient cycling and productivity in forest ecosystems. However, the long-term impacts of elevated N deposition on boreal forest soil solution composition remain uncertain. In this study, we investigate the effects of two decades of ammonium nitrate addition applied at rates of 3 (LN treatment) and 10 (HN treatment) times the ambient N deposition on soil solution collected weekly during the snow-free period at a black spruce boreal forest site located in eastern Canada. We show that N addition corresponding to 60 years (LN treatment) and 200 years (HN treatment) of accelerated ambient N deposition had nearly no important nor lasting impacts on soil solution NO3− and NH4+ concentrations. This reveals that N deposition will most likely not significantly impact Canadian boreal forests soil solution inorganic N concentration in the future. Based on these results and along with NOx emissions data measured globally in North America and on NO3–N deposition recorded at our experimental forest site, it is also likely that N deposition never affected Canadian forests’ soil chemistry in the past, even at the peak of N emission in North America in the 70 s. Our results indicate a surprisingly strong and widespread resilience of the eastern Canadian boreal forest soil solution chemistry and inorganic N content to long-term N deposition. This resilience can be partially explained by an important N-limitation in high-latitude forest ecosystems.