Nitric oxide (NO) production in injured and intact brain regions was compared by EPR spectroscopy in a model of brain and spinal cord injury in Wistar rats. The precentral gyrus of the brain was injured, followed by the spinal cord at the level of the first lumbar vertebra. Seven days after brain injury, a reduction in NO content of 84% in injured brain regions and 66% in intact brain regions was found. The difference in NO production in injured and uninjured brain regions persisted 7 days after injury. The copper content in the brain remained unchanged one week after modeling of brain and spinal cord injury. The data obtained in the experiments help to explain the problems in the therapy of patients with combined brain injury. Nitric oxide (NO) serves as a vital signaling molecule that regulates cellular metabolism and various physiological functions in the human body ,2,3,4,5.There is ample evidence pointing to the fact that the disruption of nitric oxide biosynthesis is the primary factor of the brain pathophysiological response to hypoxia-ischemia ,26,27. TEarlier, together with the team of Prof. V.B. Koshelev (Moscow State University), we conducted studies that aimed to investigate the content of NO in the focus of cerebral ischemia (left hemisphere) by using EPR spectroscopy. It showed that in the ischemic part of the left hemisphere cortex, the NO content in the spin trap decreased five times after 5 h of modeling an ischemic stroke, and this decrease persisted for a day after the stroke . In anotCerebral ischemia triggers the accumulation of excitatory amino acids in brain tissues and the activation of calcium-dependent nitric oxide synthase (NOS) isoforms, namely neuronal NOS and endothelial NOS. However, while selective inhibition of neuronal NOS demonstrates neuroprotective effects, selective inhibition of endothelial NOS produces neurotoxic outcomes ,53,54,55Disruption of cerebral oxygen supply also occurs in cases of thrombosis or an aneurysm of a blood vessel, and it often ends in the development of ischemic or hemorrhagic stroke ,15. The Ischemia and trauma of the brain and spinal cord are characterized by primary injury and subsequent secondary phase of injury ,64,65. A2−) by the cytosolic enzyme Cu,Zn-SOD [Activation of antioxidant enzymes represents a crucial defense mechanism against highly toxic oxygen radicals. The majority of these enzymes are associated with copper-containing proteins ,68. The u,Zn-SOD . This enBrain injury following subarachnoid hemorrhage occurs in two phases: an acute ischemic stroke during the initial bleeding and subsequent secondary events, among which the most fatal is the cerebral vasospasm occurring 3–7 days later . In ordeConsidering the aforementioned literature, we aimed to investigate not only the dynamics of nitric oxide production but also the copper content in both injured and non-injured regions of the frontal lobes of the brain, as well as the hippocampus, after modeling a combined brain and spinal cord injury. 2+-(DETC)2 and (DETC)2-Fe2+-NO complexes with amplitudes equal to their contribution to the spectrum of the sample. The details of determining these parameters were provided in the experimental procedures section.EPR spectroscopy was employed to study the relative intensity of NO production and copper content (as an indicator of the first and third subunits of superoxide dismutase) in injured and non-injured  areas of the brain , as well as in the hippocampus after combined injury of the brain and spinal cord. The EPR spectrum of a sample from the frontal lobe of the rat brain is given in 2+-(DETC)2 complex, representing the interaction of copper with diethyldithiocarbamate (DETC) [2-Fe2+-NO) complex spectrum (2-Fe2+-NO). As an example, we have given the EPR spectrum of the liver, the signal from which is usually intense (2-Fe2+-NO)  ,82,83. Tspectrum . In the  intense . The fraFe2+-NO) . The rel2-Fe2+-NO signal in the spectra of the investigated biological tissue samples obtained by EPR spectroscopy. This figure illustrated the spectral characteristics of both injured and non-injured  brain areas after a combined injury of the brain and spinal cord, enabling the assessment of NO production in brain tissues. The results indicated a significant reliable decrease in NO production at 84%  in the injured brain area, as well as a significant but unreliable decrease in NO production at 66%  in the non-injured  brain area, seven days after injury modeling. These findings demonstrated a distinct difference in NO production between the injured and contralateral brain areas . In the experimental data on the control samples, there were two data points close to 60; they were very different from the others. We carried out a processing option when excluding these two points from the statistical analysis (t-test (p = 0.021) and between the group “Injured rats-injured area” and group “Injured rats-non-injured area” (p = 0.05), and there is a significant difference when comparing all three groups by ANOVA test. In this case, a posteriori tests of different types showed a significant difference between these two groups 2 and g = 2.035 for (DETC)2-Fe2+-NO. The EPR signal for this complex exhibits a triplet hyperfine structure. Similar data were previously obtained [obtained .The results of spectrum analysis, as shown in The study of traumatic and ischemic brain injuries remains a prominent challenge in modern medicine ,74,78,85Trauma and ischemia of the brain involve various pathological mechanisms that contribute to the disruption of nerve and glial cell integrity, as well as damage to blood vessels ,87,88. TBrain injuries disrupt the functioning of neural networks primarily due to mechanical damage to nervous tissue and blood vessels ,91. AparIn these processes of hypoxia-ischemia and mechanical brain damage, the role of NO appears to be contradictory, capable of both neurotoxic and neuroprotective functions ,51. ConsUsing EPR spectroscopy, we investigated the relative intensity of NO production and the copper content in both injured and non-injured areas of the brain , as well as in the hippocampus, during the simulation of a combined injury to the brain and spinal cord. These molecular components are of interest to researchers who are studying the mechanisms of brain function in normal and pathological conditions. Various methodological approaches are employed for experimental analysis, the EPR spectroscopy being one of the most sensitive available techniques ,93. Signt-test (p = 0.021) and between the group “Injured rats-injured area” and group “Injured rats-non-injured area” (p = 0.05) and when comparing all three groups by ANOVA test was shown. In this case, posteriori tests of different types showed a significant difference between these two groups.The experimental analysis of brain injuries revealed a notable decrease in NO production seven days after the injury simulation, both in the injured and non-injured  areas of the brain. These results showed a distinct difference in NO production between the damaged and contralateral regions of the brain. In the experimental data on the control samples, there were two data points close to 60, which were different from the others. We carried out a processing option when excluding these two points from statistical analysis. There is a significant difference in a separate comparison between the group “Control rats” and group “Injured rats-injured area”) by In contrast, the copper content remained unchanged after seven days of injury modeling. Consequently, the trauma led to a significant decrease in NO production in both the injured and the contralateral intact brain area, while no alterations were observed in the activity of the antioxidant system. Notably, no changes in the NO production and copper content were observed in the hippocampus. This finding aligned with our previous measurements, where a brain injury was simulated using a different approach .Considering the limited efficacy of current therapeutic approaches for brain injuries and strokes and ongoing debates regarding the reperfusion period, it is prudent to conduct more in-depth research on the mechanisms and therapeutic potential of existing approaches. Moreover, it is essential to take into account the experimental findings presented by the authors of the article. These results highlighted notable distinctions in the dynamics of nitrosyl stress and the status of antioxidant protection between brain trauma and hemorrhagic stroke. Such differences offered an experimental foundation for the development of novel comprehensive therapeutic tactics in this field of medicine.n = 20) weighing between 200 and 300 g. The rats were housed in standard vivarium conditions with ad libitum access to food and water. The brain and spinal cord injury modeling was conducted at the Center of the Brain, Institute of Physiology, National Academy of Sciences of Belarus in Minsk. The experimental procedures followed the approved protocol of the Ethics Commission  of the Institute of Physiology, National Academy of Sciences of Belarus, Minsk. Tissue samples from the injured and non-injured areas of the frontal lobes of the brain, as well as the hippocampus, were collected seven days after the surgery (n = 5), and the same number of animals (n = 5) were left to evaluate the effectiveness of restoration of central control of motor functions after surgery. Tissue samples taken from intact rats (n = 5) were also used as a control group, and 5 animals were left for assessment of motor functions. These dates were chosen for two reasons: on the one hand, it is the accounting of data in previously conducted experiments with immunohistochemical staining of damaged areas of the brain [The study involved 20 male rats , xylazine (5.5 mg/kg), and acepromazine (1.1 mg/kg), administered intraperitoneally .Laboratory rats were anesthetized and secured in the prone position on the surgical table stretched by the limbs. The head of the animal was firmly secured, and the cranial vault area was prepared by removing hair and applying a 2% iodine solution to sterilize the skin. A midline incision of 10–12 mm was made along the cranial midline using a scalpel to access the underlying tissues. Locally, the periosteum was carefully dissected over the precentral gyrus, and a craniotomy was performed using a drill. The precentral region of the brain on the left hemisphere was then specifically targeted for localized brain tissue damage using a stylet. The procedure lasted approximately 3–4 min. Following the intervention, the incision was sutured, and the skin was treated again with a 2% iodine solution to minimize the risk of infection.At the next stage, we continued to conduct a surgical procedure but were already at the lumbar spinal cord level. The hair in the lumbar region was removed, and the skin was sterilized using a 2% iodine solution. A longitudinal incision was made through the skin and soft tissues, aligning with the projection of the lumbar vertebrae. With utmost care, the stylet was inserted into the spinal cord at the level of the first lumbar vertebra. When the stylet was removed, the duration of wound bleeding was observed and noted in the diary. Once the bleeding ceased, the wound was closed with two sutures, and the skin was treated again with a 2% iodine solution.Before the operation, a day after the operation, and a week (seven days) after the operation, pain thresholds  were determined in all animals.After a period of one week (seven days) following the surgical procedure, tissue samples were extracted from both the injured area and the non-injured contralateral region of the brain , specifically from the frontal lobe. Additionally, tissue samples were collected from the hippocampus. The control group of animals did not undergo surgical interventions and served as a baseline for comparison.2+ and DETC to capture NO and generate a stable ternary complex, denoted as (DETC)2-Fe2+.The problem of quantitative determination of NO in living systems needs an unambiguous solution since binding all NO produced by living organisms with iron-dithiocarbamate traps is, in principle, impossible since part of the free NO molecules bypasses the traps. Nevertheless, their complete capture is theoretically possible and can be achieved through the use of ultra-high concentrations of NO traps in cells and tissues. However, this approach entails significant disturbances in cellular metabolism . The maj4 × 7H2O, Sigma, St. Louis, MO, USA) at a dose of 37.5 mg/kg and sodium citrate at a dose of 187.5 mg/kg  was prepared immediately before injection [2-Fe2+-NO, which was insoluble in water, was formed in the presence of NO (2-Fe2+. Spin trap complex with NO (DETC)2-Fe2+-NO is characterized by an easily recognizable EPR spectrum with a g-factor value of g = 2.038 and three components of hyperfine structure [In this study, this spin trap technique was utilized for measurements. To form a spin trap, like previous experiments, DETC-Na was administered intraperitoneally at a dose of 500 mg/kg in 2.5 mL of water. Next, a solution mixture consisting of ferrous sulfate 2 complexes were recorded using a Bruker X-band (9.5320 GHz) EMX/plus spectrometer. The sample in a Broker finger Dewar was placed in a 2-cavity double resonator (model ER 4105DR) at a magnetic field modulation frequency of 100 kHz, modulation amplitude of 2 G, microwave radiation power of 2 mW, time constant of 327 ms and temperature of 77 K. Throughout the experiments, the modulation amplitude, gain, and microwave power settings were carefully selected to ensure that overmodulation and saturation of the electron paramagnetic resonance signal were avoided. These parameters remained consistent across all measurements. The sample weight used for the experiments was approximately 100–200 mg. The amplitude of the EPR spectra was consistently normalized to the sample weight to ensure accurate comparison and analysis [The spectra of the biological sample (DETC)analysis . The finger Dewar sample was placed in the first cavity from a 2-cavity double resonator, and the reference sample was placed in another cavity of the same resonator. Since each test sample was under the same conditions as the reference sample, this made it possible to quantify the intensity of the test samples and compare them in intensity with each other. 2-Fe2+-NO, which was characterized by an easily recognizable EPR spectrum with a g-factor value of g = 2.038 and three components of hyperfine structure. The g-factor is determined by the well–known formula [2+-(DETC)2 complex with a g-factor value of 2.04. As known, the spectra of this complex split into four components of the HFS [ formula ,100:hν = the HFS ,82,101. The integral intensity of the EPR spectrum is measured by the area under the absorption line ,100. For2-Fe2+-NO and Cu2+-(DETC)2 in the observed spectrum of the sample was determined sequentially. First, the relative intensity of the EPR spectrum of the complex Cu2+-(DETC)2 was calculated by the amplitude of its extreme high-field component of the hyperfine structure (HFS) (as the difference between the minimum and maximum of the first derivative of the absorption line) [2+-(DETC)2 complex with a previously determined amplitude was subtracted from the EPR spectrum of the sample. Thus, we got rid of the contribution of the signal from the Cu2+-(DETC)2 complex in the area where the signal from the complex (DETC)2-Fe2+-NO is observed. Then, the relative intensity of the EPR spectrum of the complex (DETC)2-Fe2+-NO was determined using the measurements of its central component of the HFS (as the difference between the maximum and minimum of the first derivative of the absorption line). The relative signal intensity from complexes (DETC)on line) ,99. Thent-test and Mann–Whitney test. Differences were considered significant at p < 0.05.The data are presented as the mean ± standard error of the mean (M ± m). Statistical analysis was performed using the Student’s


Through different combination schemes, the effects of different nano-SiO2 and cement contents on the strength of the stabilized materials were explored. The test results show the following: In the synergistic modification of nano-SiO2 and cement, nano-SiO2 can significantly improve the early unconfined compressive strength of red mud-based stabilized soil. In the synergistic modification of nano-SiO2, gypsum, and cement, the 7 d unconfined compressive strength of red mud-based stabilized soil is greater than 2 MPa, which meets the strength requirements of road base materials and shows the superiority of synergism. The nominal stress–strain curves are divided into five stages: compressed and compacted stage, elastic deformation stage, plastic deformation stage, damage deformation stage, and residual deformation stage. The macroscopic compressive damage pattern of the specimens shows that the modified red mud-based stabilized soil mostly exhibits brittle damage. Tests have shown that the strength of modified terracotta-based stabilized soil meets the requirements of roadbed strength.Based on the existing research results, this research team developed roadbed stabilized soil materials using nano-SiO Red mud is a solid waste generated during alumina production ,2, and iThe key to solving environmental problems in red mud disposal is to develop technologies that can directly consume large quantities of red mud or convert it into a secondary resource for reuse. Currently, in the engineering field, red mud is mainly used in the manufacture of bricks and ceramics or as a raw material for road base material ,9,10,11.2 has a high specific surface area and good volcanic ash activity in alkaline environments, which can accelerate the hydration of nano-SiO2-cement systems to form complex microstructured C-S-H gels to improve early strength [2 can play a role in the reuse of red mud. Ahmed et al. [2 in the synthesis of a geopolymer binder with red mud as the main solid source and found that the addition of suitable levels of nano-SiO2 contributed to the formation of geopolymer gels and C-S-H, giving geopolymer higher compressive strength. The relevant literature shows that nano-SiO2 has obvious performance advantages and can play a great role in civil engineering. However, there is little research on how to utilize the advantages of nanomaterials in red mud modification for strength improvement. Meanwhile, whether the strength of the modified red mud-based stabilized soil meets the strength requirements of roadbed materials and strength characteristics needs to be further studied. Therefore, this paper aims to develop red mud-based stabilized soil materials and synergistically involves nano-SiO2 in the modification of red mud stabilized soil to study the effect of nano-SiO2 on the enhancement of the strength of red mud stabilized soil. The thesis focuses on analyzing the strength characteristics of modified red mud-based stabilized soil and studying the feasibility of using it as a road base material from the perspective of strength. The research results can provide a reference for the resource utilization of red mud.Nano-SiOstrength ,22,23,24d et al.  added naThe red mud used was Bayer red mud, taken from an aluminum company in Guangxi Province. The specific gravity of the tested red mud was 3.06. The natural moisture content of the red mud was in the range of 28.10~35.21%.In accordance with the standard for geotechnical testing method , the parThe red mud contains trace heavy metal elements. In accordance with the Chinese industry’s standard solid waste extraction procedure for leaching toxicity—the acetic acid buffer solution method —a leachiCombined with the Chinese national standard for pollution control on the landfill site of municipal solid waste , it was 2 has a high specific surface area and good volcanic ash activity in alkaline environments, which improves early strength. The selected nano-SiO2 was produced by the mechanical crushing process. The nano-SiO2 is a white spherical powder with 99.9% purity. Its particle size ranges between 1 and 100 nm. The specific surface area of the nano-SiO2 particle is 240 m2/g.Nano-SiO2/kg and a density of 3.10 g/cm3. According to the Standard Specification for Portland Cement [Cement is a commonly used curing agent that significantly increases the strength of modified soils. The cement used for the test was 42.5-grade ordinary silicate cement with a specific surface area of 340 md Cement , the sel2+ ions to the liquid phase of red mud-based stabilized soil. Under the alkaline environment, the secondary hydration reaction occurs, generating C-S-H and C-A-H hydrated gels, which enhance the strength of the modified soil. The gypsum chosen for the experiment is a kind of construction gypsum. It is a white powder with a density of 2.32 g/cm3, and its chemical formula is CaSO4-0.5H2O.Gypsum can continuously provide Ca2 was incorporated into the red mud-based stabilized soil at a mass ratio of 0.5%, 1%, 1.5%, 2%, 2.5%, and 3%; gypsum was incorporated into the red mud-based stabilized soil at 6% of mass ratio; and cement was incorporated into the red mud-based stabilized soil at 1%, 3%, 5%, 7%, and 9% by mass.In combination with the studies of ,30, nanoAdding cement alone to dry red mud and testing the effect of the individual admixture of cement on the strength of the specimen;2 dosing of 1% was selected to test the effect of different cement dosing on the unconfined compressive strength of specimens under the synergistic effect of nano-SiO2;The nano-SiO2 were added on this basis to test the synergistic effects of the three modified materials on strength control and to determine the optimum nano-SiO2 dosage.The optimum dose of 3% cement and 6% gypsum was selected from both strength and economic considerations, and different mass ratios of nano-SiOThe test procedure was as follows:2, cement, and gypsum, respectively; the following number refers to the blending mass ratios of corresponding materials (%).The synergistic combination scheme of the experimental design is shown in The stabilized soil with different sterilizers, as shown in Firstly, the sampling red mud was dried at room temperature and crushed into powder with a plastic hammer; then, the crushed powder was sieved using a 0.5 mm steel sieve; the sieved red mud was oven-dried at 105 °C to further remove the moisture.In accordance with the optimal water content determined by the compaction test, the modified materials  and a certain mass of deionized water were added into the red mud according to the designed dosage and mixed thoroughly.The stabilized soil was compacted to a 5 mm × 5 mm cylindrical column. Note that the compaction should be done within 1 h after adding cement.The compacted specimens were sealed with plastic film and placed in an environmentally controlled chamber with a temperature of 20 °C and relative humidity of 95° for curing. After reaching different curing periods of 1, 7, 14, 28, 60, and 120 days, the specimens were taken out for unconfined compressive strength tests.The specimen preparation and curing steps are as follows:The unconfined compression test was carried out by a TSZ series fully automatic triaxial instrument produced by Nanjing Soil Instrument Factory Co. . The instrument can directly obtain the experimental maximum compressive strength and the relationship curve between the main stress difference and axial strain. The experimental parameters were set as follows: specimen height, 5 cm; specimen diameter, 5 cm; rigid steel ring coefficient, 30 N/mm; axial strain, 15%; loading level, 1 level; sampling step, 0.125 mm; shear rate, 2.5 mm/min.Once the experiment has started, the instrument can automatically collect the compressive strength data and generate the stress–strain curve simultaneously until the specimen is completely damaged and loses its compressive capacity. uq is the compressive strength of the specimen (MPa), accurate to 0.01 MPa; P is the breaking load of the specimen (N); A is the pressure-bearing area of the specimen (mm2).The unconfined compressive strength is calculated according to Equation (1):When the cement was modified alone, the specimens were dosed with 1%, 3%, 5%, 7%, and 9% of cement. The test results are shown in The unconfined compressive strength of cement-modified red mud-based stabilized soil increased with the increase in the curing time. The unconfined compressive strengths of cement with 3% admixture are 463, 948, 1289, and 1466 kPa at 1, 7, 14, and 28 d, respectively, with the growth values of the first 7 and 28 d compressive strengths accounting for 48.3% and 82.3% of the growth values of the 28 d compressive strength.2, gypsum, and cement will be analyzed, focusing on the effect of the synergistic effect of nano-SiO2 on the strength of red mud-based stabilized soil.Management scientist Ansoff  believes2 with the cement admixture still at 1%, 3%, 5%, 7%, and 9% and the nano-SiO2 in cooperation with the cement. The test results are shown in The increase in the unconfined compressive strength of the red mud-based stabilized soil was tested by adding 1% nano-SiO2 co-cement showed a linear increase with the increase in cement admixture. For example, the unconfined compressive strength at 7 d was 865, 1434, 1892, 2273, and 2547 kPa for 1%, 3%, 5%, 7%, and 9% of cement admixture, respectively. For each 2% increase in cement, the increases were 569, 458, 381, and 274 kPa, respectively.2 co-cement increased with the increase in the curing time, but the growth rate of the unconfined compressive strength was significantly greater when the curing time increased from 1 d to 7 d than when the curing time increased from 7 d to 14 d and from 14 d to 28 d. The growth rate of the unconfined compressive strength of the red mud-based stabilized soil modified with nano-SiO2 co-cement increased with the increase in the curing time.The unconfined compressive strength of the red mud-based stabilized soil modified with nano-SiO2 with and without the addition of nano-SiO2, provided that the cement admixture is 3%. The NS1PC3 combination of nano-SiO2 synergistically modified with cement showed a large increase in unconfined compressive strength with curing time. For the same curing age, the unconfined compressive strength of the NS1PC3 synergistically modified combination increased by 27.7%, 51.2%, 54.5%, and 56.1%, respectively, compared to the PC3 alone modified combination. In addition to this, there is a characteristic that the growth of the lateral limit compressive strength tends to increase from 1 to 7 d, and the subsequent growth is more moderate, indicating that the growth rate of the lateral limit compressive strength is mainly concentrated from 1 to 7 d. This indicates that the synergistic effect of nano-SiO2 and cement improves the early unconfined compressive strength of the red mud-based stabilized soil.2 was selected at 0.5%, 1%, 2%, and 3% to test the increase in unconfined compressive strength of red mud-based stabilized soil under the action of nano-SiO2 in cooperation with cement and gypsum. The test results are shown in Under the premise of 3% of cement and 6% of gypsum, nano-SiO2 with 0.5%, 1%, 2%, and 3% doping were 2421, 2748, 2467, and 2156 kPa, respectively. The unconfined compressive strength did not increase with the increase in nano-SiO2 doping, and the highest strength was achieved with the combination of nano-SiO2 with 1% doping. Referring to the Technical Guidelines for Construction of Highway Roadbases [It can be found that when the curing time was 7 d, the unconfined compressive strengths of nano-SiOoadbases , the 7 d2 dosing of 1%. 2. The 7 d unconfined compressive strength of NS1CS6PC3 reached 2748 kPa, which meets the strength requirements as a general road stabilized soil. The cement dosing was not the highest for the selected combination, considering the economic requirements, which is the optimal combination from the strength point of view. The next best combination is NS2CS6PC3.In contrast, the unconfined compressive strength of the modified red mud-based stabilized soil increased with the increase in the curing time, and the growth rate of the unconfined compressive strength was the largest in the curing age of 7 d. The growth value of compressive strength in the first 7 d accounted for 69.2% of the growth value of compressive strength at 28 d, based on the nano-SiO2, gypsum, and cement will be analyzed, focusing on the synergistic effect of nano-SiO2.In this section, the synergistic modification characteristics of nano-SiO2, were tabulated and analyzed as shown in The 7 d unconfined compressive strength results of the gypsum and cement dosing for the optimal combination determined in the test, i.e., at 6% gypsum and 3% cement, for the corresponding combinations with and without nano-SiO2 before and after modification concluded the following:(1)When the red mud is unmodified, the unconfined compressive strength of the specimens made under the conditions of 93% compaction, optimum moisture content, and maximum dry density is 388 kPa, which has a structural strength. However, because no modified material is added, the unconfined compressive strength cannot be enhanced with the increase in curing time. At the same time, the structure of the compacted specimens will be damaged if disturbed by external forces.(2)2 was added, the compressive strength of the red mud-based stabilized soil reached 1434 kPa, which was 1.5 times that of the compressive strength of the red mud-based stabilized soil modified by PC3 alone. The synergistic effect of nano-SiO2 promoted the modification of the red mud-based stabilized soil and led to further growth of the lateral-free compressive strength.Cement modification alone can make the red mud-based stabilized soil obtain higher compressive strength than that of unmodified, and the 7 d unconfined compressive strength with 3% cement admixture is 948 kPa, which is about 2.5 times that of unmodified compressive specimens. When 1% nano-SiO(3)2 was modified with CS6 and PC3, the modified red mud-based stabilized soil obtained higher unconfined compressive strength. The 7 d unconfined compressive strength obtained at 1% nano-SiO2 was 2748 kPa, which was greater than the strength of 591 kPa of NS1 modified with CS6 and 1434 kPa of NS1 modified with PC3, and greater than the sum of 2025 kPa. This value is greater than the strength of NS1-modified soil with CS6 of 591 kPa and the strength of NS1-modified soil with PC3 of 1434 kPa and is greater than the sum of both of them of 2025 kPa. The synergistic effect of nano-SiO2 with CS and PC has obtained the effect of “1 + 1 > 2”.When nano-SiO(4)The above series of unconfined compressive strength tests gradually revealed the optimal amount of the three modified materials while further revealing the superiority of the synergistic effect to enhance the compressive strength of the modified materials, and NS1CS6PC3 was the best modified solution for the test from both economic and strength considerations.The analysis of the synergistic effects of the involvement of nano-SiO2, gypsum, and cement synergistically modified at the age of 28 d are used to label the stage division.In the first stage, the OA section, the slope of the stress–strain curve increases continuously and is concave, but the course is short. The analysis suggests that the specimen is formed in this stage because the pore ratio under pressure becomes smaller, the specimen soil particles and the modified materials not involved in the reaction are further compacted, and the stiffness increases, resulting in increasing compressive strength. This stage belongs to the “compacted stage”, and the shape of the curve of the red mud-based stabilized soil is basically the same in this stage under each modification condition.2, while In the second stage, the AB section, the stress–strain relationship curve in this stage is approximately linear, and the nominal stress of the red clay-based stabilized soil increases linearly with the increase in the nominal strain. This stage is the “elastic deformation stage”, and the stress corresponding to the B point is the proportional limit. The shape of the second stage is slightly different under different modification conditions, but in general, the higher the compressive strength is, the higher the B point is in the stress rise stage. As shown in In the third stage, the BC section, the slope of the stress–strain curve in this section is decreasing, the shape of the curve is concave, the stress reaches the peak and then stops growing, and the peak stress, i.e., the corresponding stress at point C is the unconfined compressive strength of the test material. This stage is the “plastic deformation stage” of the test material, which is also the “yielding stage”. In this stage, after the stress exceeds the proportional limit, the strain increases significantly with the increase in stress, and the terracotta stabilized soil softens, resulting in microcracks in the test material, which are mainly parallel to the loading direction. Then, with a further increase in load, the microcracks in the specimen also increase and gradually extend and expand, and the duration of this process is relatively short. The presence of penetrating microcracks implies irreversible damage to the red mud-based stabilized soil. However, the curve pattern shows that the specimen material can still withstand the increased load until the stress reaches the peak. When the stress state reaches the peak, a fall occurs, which is caused by the continuous development of microcracks through the development of the material load-bearing capacity decreases and destabilization, and finally enters the fourth stage—the damage deformation stage.In the fourth stage, the CD section, after the curve crosses the peak from point C, the nominal stress decreases sharply with the increase in strain; this stage is the “damage deformation stage” of the material. Also similar to the second stage, the curve shape is slightly different under different modification conditions. In general, the higher the strength of the material, the more rapidly the stress decay, such as PC alone. For example, the higher the PC dose, the higher the rate of decline of the curve for the red clay-based stabilized soil modified by PC alone, and the greater the rate of decline of the curve for the red clay-based stabilized soil modified by NS1CS6PC3, the greater the rate of decline of the curve at this stage with the increase in the curing age, showing the characteristics of “brittle damage”. In the “damage deformation stage” of the material, the cracks of the red clay-based stabilized soil penetrate the top and bottom of the specimen; the cracks keep increasing, and the material strain of the specimen softens and destabilizes, leading to the rapid decay of the material resistance.The fifth stage, the DE section, is the “residual deformation stage” of the test material. In this stage, the specimens produce a lot of plastic deformation. Terracotta-based stabilized soil, after the destruction of the stress, does not disappear completely, and even some specimens still retain a small value; the strength is the residual strength, but with the increase in stress, the nominal stress will eventually tend to zero. The compressive specimens of each modified red mud-based stabilized soil also roughly show two different characteristics at this stage. Most of them have a stress “damage platform”, and after the “damage platform”, the nominal stress decays rapidly again, and a few of them do not have a “damage platform”, and the stress gradually decays. For example, in the case of the red mud-based stabilized soil specimen modified by cement alone, the higher the PC admixture, the higher the unconfined compressive strength. Furthermore, the “damage platform” is shown in the fifth stage, where the nominal stress does not continue to decay but appears to “stagnate” with strain growth; the nominal stresses decayed rapidly again and tended to zero until the end of the test. The stress–strain curves of NS1PC-modified red clay-based stabilized soil showed the characteristics of “damage platform” in all specimens at this stage, with the difference that NS1CS6PC3-modified red mud-based stabilized soil, the nominal stress did not show the platform effect when the curing age was short, but when the curing age reached 120 d, the platform effect was obvious. Combined with the analysis of the typical damage pattern of red mud-based stabilized soil under compression in The ratio of residual stress to peak stress is shown in From the above analysis, it can be seen that the red mud-based stabilized soil has different deformation mechanisms during uniaxial compression. During the compressive compacting stage, the material mainly shows that the pore ratio becomes smaller, the material particles are further compacted, and the compressive strength is further enhanced. In the elastic stage, the material particle compactness continues to be strengthened, and the external load is resisted through the cohesion and friction between particles. When the external load is continuously increased, the resistance of the material is continuously enhanced, but still, no cracks appear to form in the material. In the plastic stage, microcracks appear in the material, gradually extend and expand, penetration cracks form and irreversible damage occurs. However, the material is not destabilized and damaged, and the compressive strength can still increase with the increase in external load and reaches the peak before the material destabilization and damage. Moreover, there is an obvious strain softening behavior of the material. In the damage stage, the cracks keep increasing and are accompanied by the specimen fragment body falling off from the main body of the specimen. The material resistance decays rapidly, but before the compressive capacity completely disappears. Before the complete loss of compressive capacity, most of the specimens showed the ductility characteristics of increasing stress invariant stress, indicating that the red mud-based stabilized soil has good buffering performance and still has a certain bearing capacity after the damage. Finally, with the increase in compressive time, the specimens were completely destabilized and destroyed.(1)2 is modified with cement, nano-SiO2 can significantly improve the early unconfined compressive strength of red mud-based stabilized soil; when nano-SiO2, gypsum, and cement are modified with 6% gypsum and 3% cement, under the synergistic effect of nano-SiO2 , the 7 d unconfined compressive strength of the red mud-based stabilized soil was greater than 2 MPa. The maximum was achieved at 1% nano-SiO2, satisfying the strength requirements of the roadbed material. The synergistic results of the addition of nano-SiO2, gypsum, and cement showed the superiority of synergy. Compared with other modification research results, the amount of red mud in the red mud-based stabilized soil is relatively high, accounting for 90%, so the application of the research results in roadbed filling can consume a large amount of red mud and has a good development prospect.Cement alone can improve the unconfined compressive strength of red mud-based stabilized soil; when nano-SiO(2)The compressive damage patterns of the specimens showed that most of the modified terracotta-based stabilized soils exhibited brittle damage, especially when the modified materials and the age of maintenance promoted conditions that increased the nominal stresses. Under the condition of increasing uniaxial pressure, vertical cracks appeared in the specimens first, and with the increase in cracks, slip appeared at the bottom. As the pressure increases, transverse cracks appear in the specimen, and the transverse cracks promote shear damage on one side of the specimen. When the other side without transverse shear damage also produces damage, the specimen is finally completely destroyed.(3)The compressive deformation of the red mud-based stabilized soil shows the characteristics of elastic-plastic deformation, and the nominal stress–strain curves of the red mud-based stabilized soil under each modified condition are divided into five stages: “compressive compacting stage”, “elastic deformation and plastic deformation stage”, “damage deformation and residual deformation stage”, and so on. Most of the specimens showed “damage platform”. Most of the specimens showed a ductile character with small changes in stress but with an increase in stress variation before the resistance to compression was completely lost, indicating that the red mud-based stabilized soil has good buffering performance. It is more suitable to be applied as road base material for general roads.In this experiment, the stabilized soil material was prepared by modifying the red mud from aluminum industrial waste, and the strength characteristics of the red mud-based stabilized soil with different modified materials and different amounts of modified materials were tested and analyzed. The main findings were as follows:


The formation of AlF3-based nano- and micro-wires can bring new functionalities to AlF3 material. AlF3 nanowires are used, for example, in functionally modified microprobes for a scanning probe microscope. In this work, we investigate the AlF3 samples obtained by the reaction of initial aluminum with an aqueous hydrofluoric acid solution of different concentrations. The peculiarity of our work is that the presented method for the synthesis of AlF3 and one-dimensional structures based on AlF3 is simple to perform and does not require any additional precursors or costs related to the additional source materials. All the samples were obtained under normal conditions. The morphology of the nanowire samples is studied using scanning electron microscopy. We performed an intermediate atomic force microscope analysis of dissolved Al samples to analyze the reactions occurring on the metal surface. The surface of the obtained samples was analyzed using a scanning electron microscope. During the analysis, it was found that under the given conditions, whiskers were synthesized. The scale of one-dimensional structures varies depending on the given parameters in the system. Quantitative energy-dispersive x-ray spectroscopy spectra are obtained and analyzed with respect to the feedstock and each other.AlF AlF3-based glasses demonstrate enhanced chemical and thermal stability and excellent moisture resistance, and are successfully used in infrared lasers [Metal fluorides are promising for catalysis applications ,2,3,4,5,d lasers .3), which is an inorganic crystalline substance under normal conditions. Due to its electro-physical properties, it finds applications as a catalyst in organic synthesis, as an additive for electrolytes for lowering melting points, as flux for oxide separation and removal [3 is a component of the AlF3/ThF4 heterostructures, which are superior to the LiF/ThF4 optical structures in terms of their optical parameters. The authors of the work [3/SiO2/Si system allows one to localize a high density of fixed negative charges in fluorine vacancies, serving as a source of a strong drift field [3/polyimide films increase dielectric permeability as well as reduce leakage currents compared to conventional polyimide films [3 can also be used to prevent tooth discoloration [3 can be used as a film to cover the electrode surfaces of lithium-sulfur batteries to prevent the “shuttle effect”, which results in the transfer of polysulfide and the formation of dendrites. This leads to a sharp decrease in productivity and low kiln efficiency [3 as a surface coating improves the electrochemical characteristics of K1.39Mn3O6 microspheres, which, in turn, has a beneficial effect on the cyclic stability, reversible capacity, and high-speed capacity of batteries. The stabilized structure of AlF3 can play the role of a physical isolator between the active substances and electrolytes to prevent the occurrence of adverse reactions and inhibition of transition metal ions in batteries [3 material, which is why a cost-effective synthesis technology of one-dimensional AlF3 structures is highly desirable.One of the most important representatives of binary compounds, MeF3, is aluminum fluoride  structures, such as nanorods, nanowires (NWs), and nanotubes, enables a high surface-to-volume ratio. This makes 1D AlF3-based structures promising for use in supercapacitors and nano-probes of different types [3-based NWs [3 without the use of aggressive hydrofluoric acid HF. One of the most popular methods for synthesizing AlF3 nanoparticles is the fluorolitic sol-gel synthesis [Synthesis of AlFnt types ,21,22,23ased NWs ,28,29,30ynthesis , which cIn the first reaction, water as a reactant is completely replaced with hydrogen fluoride, which leads to the formation of M-F bonds. The second reaction, if performed correctly, leads to the formation of either metal oxides or nanoscale metal fluorides. Fluoride ions tend to form stable bonds. Consequently, there are not many examples of crystalline fluorides containing fluorine at the ends. One problem with solution-based synthesis methods is that in such reactions we face a system depending on several parameters including time, solution saturation, and amount of solution. In addition, when synthesizing metal fluorides, it should be taken into account that they have a high lattice energy, which makes it difficult to form regular crystal structures . Helical3 for use in a large variety of applications, developing a more simple method to synthesize AlF3 NWs is desired. The newly proposed production technology should ensure the repeatability of synthesized one-dimensional structures, should not require extreme parameters of the medium, and it is preferred that this method is realized under normal conditions. The current paper presents the synthesis method for AlF3 NWs satisfying all these conditions and reports the results of the morphological and compositional characterization of the obtained NWs. These NWs are synthesized in the direct reaction of hydrofluoric acid solution with aluminum under normal conditions. Two cases are considered: a synthesis reaction with food-grade aluminum used for crockery and household appliances, which includes a small proportion of additional components, as well as a reaction with aluminum of a purity of 99.99%. The morphology and composition of the NW samples are studied versus the concentrations of hydrofluoric acid reacting with pure aluminum.As follows from the promising nature of 1D AlFf). In the analysis of the alloy using EDX method, the following composition was determined: Al = 98.95%, Si = 0.67%, Ca = 0.05%, Fe = 0.21%, Ni = 0.13%, and Zn—0.02%. Pieces of this raw aluminum alloy were cut into 20 × 20 mm samples  of different concentrations, see The experiments were carried out as follows. Two types of aluminum alloy were investigated. The first was the food-grade aluminum taken from a 1.7 L pot by KALITVA COOK and served as a raw material for the study (Alp) in the form of pellets, with a nominal pellet mass of m = 2.435 g. This aluminum of grade N4 was produced under technical conditions ETO.021.051 and contains a mass ratio of additives of 0.015% or less. In the second group of experiments, a single pellet was exposed to 40 mL of the hydrofluoric acid of different concentrations, see The second sample under investigation was the pure aluminum  Zeiss Supra 25 , equipped with an energy dispersive X-ray analyzer (EDX) Ultim Max 100 . An intelligent microscope, NT-MDT NTEGRA THERMA , was used for atomic force microscope (AFM) analysis.3∙H2O was obtained, while both reactants and the conditions of the reaction sufficiently differ from those reported in the literature. One of the best-known methods of obtaining aluminum fluoride is neutralizing hydrofluoric acid with aluminum hydroxide 3HF + AL(OH)3 = AlF3 + 3H2O at 90–95 °C applied for one hour. In the course of the reaction, aluminum fluoride crystallizes as AlF3∙H2O, after which the precipitate is dehydrated at 350 °C [f pellets.In the first experiment, it was assumed that after a reaction between hydrofluoric acid and an aluminum sample, AlFt 350 °C . It is pAccording to the AFM results obtained, exposure to HF disturbed the integrity of the original surface, forming a stepped-grid structure, shown in A series of tests with hydrofluoric acid of different concentrations was carried out. As the concentration of hydrofluoric acid in the solution increased, the initial structure of the resulting precipitate changed. During the reaction of sample 6.1 with 8% solution, the precipitate obtained during the reaction copied the shape of the container in which the experiment took place in 2. EDX was also used to determine the microwire composition.2.The following analysis revealed that the percentage of Zn in the microwires was higher than in the matrix as a whole. It is interesting that, depending on the concentration of the solution of HF with which the initial material interacted, the size of the wires and their geometry can change. For example, 2.The SEM of sample 4.1 is given in During the study of the formation of 1D structures, an interesting fact was discovered. It transpired that NWs did not form in the reaction with maximum concentration. Thus, in the synthesis of sample 1.1, no NWs were formed, and the microstructure of the material is a rough surface.p) samples. f and Alp reactions appear very similar.To further clarify and strengthen the results, we performed a series of experiments with pure Al  at magnification, the sample began to crack. The microstructural surface was smooth (the inhomogeneities presented on it could appeared due to dislocation defects) and the 1D structures were inside the clefts. In the samples with a solution concentration of 32.6%, 1D structures were nanoscale and did not have hexagons at their base, but rather resembled needles, see The difference can be also found in the resulting macrostructure. In the 16.3% solution, the sample is completely white without the formation of an additional phase, while in the 40% solution the precipitate is flake-like crystallites. The flakes formed with Alf and Alp are stoichiometric compounds of AlF3. In the case of Alf, the total impurity is less than 1%.After synthesis, samples 5.1 and 6.1 with the formed NWs were heated to 65 °C. The NW surface remained unchanged, indicating the thermal stability of the obtained structures.3 structures under normal conditions by direct exposure of aluminum to the hydrofluoric acid in accordance with the general equation.We have demonstrated the possibility of obtaining one-dimensional AlF4. The food-grade alloy exposed to HF showed an intensive reaction catalyzed by additives, while the pure aluminum reacted calmly. The analysis of the reaction products was carried out using AFM, SEM, and EDS, confirming that in most cases AlF3 NWs are synthesized.Two types of aluminum alloy were investigated: food-grade aluminum and pure aluminum N3. Under normal conditions, two thermodynamically stable phases of AlF3 are known, denoted as α and β, and some metastable phases . The α-AlF3 phase has a rhombic structure similar to that of perovskite, while the β-AlF3 phase has a hexagonal structure [3 phases of Al, Fe and Cr are isostructural and exhibit a hexagonal tungsten bronze structure (HTB) in which MF6-octahedra form hexagonal channels through the structure [3 phase in our experiments. To date, there have been two main methods of β-AlF3 synthesis: by dehydration of α-AlF3∙3H2O and by growing crystals from chloride flux [3.The question remains on the obtained allotrope of AlFtructure ,34. In g3 was formed, and the dendritic morphology of the resulting structure is due to the high thickness of the residue (approximately 700 microns). It cannot be said that the growth of one-dimensional structures occurred parallel to each other in view of the possible curvatures of the polypropylene substrate on which the synthesis took place. At some point, the structures must intersect and break in view of the influences exerted on each other and the presence of structural deformations. On the foundation of the already formed NWs, the synthesis of new ones begins, with which exactly the same process occurs. After some time, we observe an entire surface occupied with one-dimensional structures fused one into the other. Based on the data obtained, it is also possible to assume a decreasing dependence of the height of a NW on its diameter: the smaller the diameter is, the higher the nanowire is [We assume that a monolayer of filamentous AlFowire is .3 NWs versus the conditions of our synthesis process in more detail, it is required to conduct a series of tests for growing the NWs under different supersaturations of the solution and on different substrates, for example 4H-SiC, in order to determine the evaporation rate of the solution, the corresponding rate of nucleation, and the axial growth rate of the NWs, similarly to what has been achieved for III-V semiconductor NWs [In order to study the mechanism, growth kinetics, and crystal structure of AlFctor NWs . To set When analyzing the structures using SEM, a tendency of charging of the samples was observed. From the first sample to the sixth, the charging capacity of the sample increased, due to which the obtained images had a noisy background.3 nanowires might be lower with the proposed technique than with the existing ones, which implies that NWs may be widely applied in sensors, high-performance electronics, and scanning probe microscopy. The obtained stoichiometric Alp-based AlF3 NWs can also be used as a dielectric in supercapacitors due to their predisposition to active charge accumulation. The robustness of the technological method under normal conditions enables the fabrication of new composite materials based on AlF3, obtaining multilayer structures with 1D nanocrystals with interesting electro-physical properties that can be used for the design of different microelectronic components.Due to the easiness and simplicity of the production method, the possible production costs of AlFFuture studies will be dedicated to increasing the quality of the NW output as well as finding the optimal concentration of HF and additives conducive to the best performance of the reaction. Developing an industrial-scale technology from the shown experimental one is of certain interest as well.


Soil-bentonite vertical cut-off wall is an emergency technique used for contaminant control in geo-environmental engineering, high-density polyethylene (HDPE) geomembrane (GM) with an extremely low-permeability coefficient is expected to enhance the contaminant barrier effect of the vertical cut-off wall. To evaluate the barrier performance of the composite barrier composed of GM and soil-bentonite mixture towards organic contaminant, while also quantitively revealing the impact of GM defects and placement, a one-dimensional transport model for organic contaminants in composite barrier is solved under semi-infinite boundary conditions. The proposed transport model is validated by numerical simulations using COMSOL Multiphysics 5.4, and the effects of GM defect rate, placement within the composite isolation wall, and contact level with soil-bentonite on contaminant transport behavior are further studied. The results show that as the average frequency of GM defects increases from 2.5 to 50 holes per hectare, the breakthrough time of organic contaminants through composite barrier decreases by almost 70%. Poor contact level between GM and soil-bentonite mixture may reduce the breakthrough time of the composite cut-off wall by 65%. Although the selection of GM placement has limited impact on the transient flux of contaminants, it does affect the total flux of contaminants over a certain period of time. The effects of permeability coefficient, effective diffusion coefficient, distribution coefficient, and hydraulic head of the composite cut-off wall can be considered by the proposed analytical solution, which would provide guidance and reference for the design and service performance evaluation of the composite cut-off wall. The employment of a liner barrier constitutes a crucial engineering intervention aimed at curtailing the spread of organic contaminants to the surrounding ecosystem, particularly in regions including but not limited to landfill sites, mining smelter ponds, and industrial parks . OverallThe investigation of contaminant transport and the barrier effects of liners is a topic of great importance to engineers and researchers. The diffusion coefficient of organic contaminants in liner materials plays a critical role in determining breakthrough time, and the utilization of low-permeability GM + GCL composite liner can be challenging due to its inherent difficulty in taking full advantage of its low-permeability coefficient . Wu et aThe defect of GM cannot be ignored, and the impact of leakage on contaminant transport should be clarified. Lee et al. 2000)  found th. (2006)  studied . (2006)  found th00  foundIn this study, considering convection, diffusion, and adsorption effects, a one-dimensional transport model of organic contaminants in a composite vertical impermeable cut-off wall with defective GM and soil-bentonite barrier was established. The mathematical physical equation method was used to obtain the analytical solution of the model, and then the calculation results of the analytical solution were compared with the calculation results of the numerical simulation method to verify the accuracy of the model. Then, further analysis was conducted on the influence of parameters such as GM defects, location, and adsorption capacity on contaminant transport in the vertical impermeable cut-off wall.The schematical diagram of the organic contaminant transport in composite vertical cut-off wall with defective GM is shown in C0; (4) molecular diffusion follows Fick’s second law, and the contaminant adsorption is an isothermal linear process that has reached equilibrium; (5) the barrier and aquifer are homogeneous and isotropic, and under the head of the filtration liquid, the seepage reaches a steady state.To obtain an analytical solution for the one-dimensional migration of organic contaminants in the vertical contaminant barrier, the model adopts the following assumptions based on previous theoretical foundations and related experimental studies: (1) the contaminant in the filtration liquid is a single organic contaminant and undergoes one-dimensional migration in the horizontal direction; (2) the vertical impermeable cut-off wall remains undeformed with a constant pore volume, and the geomembrane contains holes; (3) the contaminant migration considers convection, diffusion, and adsorption effects, and contaminant concentration in the leachate is assumed to be constant at f is the contaminant flux, n is the total porosity of soil, v is the seepage velocity, C is the contaminant concentration, and D is the molecular diffusion coefficient.Considering the convection and diffusion effects of contaminants, the flux of contaminants along the C1 is the contaminant concentration at any position x within the geomembrane, D1 is the effective diffusion coefficient of the GM, and v1 is the average linear velocity of the contaminant in the geomembrane.In the geomembrane, contaminants mainly undergo convection and diffusion. Considering its relatively thin thickness, here it is assumed to be in a steady-state transport. The steady-state transport governing equation for the GM is:dR is the retardation factor of the soil-bentonite barrier [2C is the contaminant concentration at any position x in the soil-bentonite barrier at any time 2D is the effective diffusion coefficient of the soil-bentonite barrier, and 2v is the average linear velocity of the contaminant in the soil-bentonite barrier.dρ is the dry density of the soil-bentonite barrier; n2 is the porosity of the soil-bentonite barrier; and dK is the distribution coefficient of soil-bentonite barrier.The soil-bentonite barrier has a low permeability, which can prevent the penetration of contaminants and adsorb contaminants within a limited thickness. According to previous assumptions and the law of conservation of mass, the transient one-dimensional transport governing equation of contaminants in the soil-bentonite barrier can be expressed as follows. barrier , C2 is tAssuming that the background concentration of contaminants in the vertical cut-off wall is zero and the redistribution process of contaminants at the interface between the infiltration liquid and the GM is instantaneous, the boundary at the interface between leachate and GM can be expressed as follows:gK is the concentration distribution coefficient between the GM and the adjacent medium, and gK’ is equal to dK [The continuity conditions between the GM and the soil-bentonite barrier are:al to Kd .When considering convection in contaminant transport, boundary conditions have little effect on the transport results . Here, wk1 and k2 are undetermined parameters, here we set r1= v1/D1 and r2= v2/D2. By substituting the Equation (5) and the Equation (7) into Equation (10):The general solution of the governing Equation (2) is:Substituting Equations (10)–(12) into the Equation (8):U is the Laplace transform of C2 with respect to t and p is the transform parameter.For the governing Equation (3), we use Laplace transform method to solve it:k3 and k4 are constants, and expressions of λ1 and λ2 are as follows:Taking Laplace transform on both sides of the governing Equation (3):Laplace transform of the Equations (9) and (13):By substituting Equations (20) and (21) into Equation (17):Substituting the obtained parameters into Equation (17):Applying the inverse Laplace transform principle and related properties to Equation (24), we can obtain:Substituting Equation (25) into Equation (1) yields the expression of contaminant flux:The application of numerical methods in engineering is quite common. In order to further verify the accuracy of the analytical model, this paper uses the numerical simulation software COMSOL for simulation research, and the related calculation parameters are listed in t = 5 a, 10 a and 20 a, the calculation results of the analytical model in this paper are in good agreement with the concentration distribution curve obtained by the numerical simulation software. This further validates the correctness of the analytical model proposed in this paper.dh on both sides of the vertical barrier is 0.3m and the initial concentration of benzene C0 is 1.63 mg/L, the breakthrough criterion was set to be 0.1, which means that the barrier was considered to be breached when the ratio of the outside concentration of the vertical cut-off wall to the initial concentration reached 0.1.Based on the one-dimensional transport model established in this article, the impacts of convection, diffusion, and adsorption on the transport of organic contaminants in the composite cut-off wall were systematically studied. The effects of model parameters on the transport of organic contaminants in this vertical cut-off wall were comprehensively analyzed. Benzene, which has a strong migration ability, was selected as the single organic contaminant in landfill leachate . Assumindh is the hydraulic head difference, wL is the connected fold lengths, l is the thickness of adjacent media, k is the permeability coefficient of adjacent media, wb is the half-width of the folds, θ is the transmissivity between GM and adjacent media. The expressions for excellent contact, good contact, and poor contact conditions are provided by Equations (28) to (30), respectively [Considering the situation where GM has holes, the simplified formula for calculating the volume leakage rate of the vertical barrier is provided by the following equation .(27)Q=2ectively .(28)logam on the GM is expressed per hectare, the Darcy flux through the barrier is provided by the following equation [A is the cross-sectional area of the area under investigation.Assuming that the hole frequency equation .(31)va=According to the law of mass conservation, the relationship between the seepage velocity in the GM and the soil-bentonite barrier is provided by the following equation:wL = 500 m. The thickness l and permeability coefficient k of the soil-bentonite barrier were used. The half-width of the folds is wb = 0.1 m, and the transmissivity is θ = 3.2 × 10−9 m2 [In this study, the fold length  10−9 m2 . Other p 10−9 m2 ,30, and 2 [The phenomenon of geosynthetic liner with holes is quite common and can be caused by various factors. The shape and size of the holes are also diverse. The hole frequencies on GM were 4 and 22 holes/ha respectively under good and poor construction quality with an average hole area of approximately 1 cm2 . Figure The interface hydraulic conductivity between the GM and adjacent media can affect the amount of leakage, and its magnitude is determined by the contact conditions. In order to investigate the influence of GM location on the anti-seepage performance of vertical cut-off wall, the organic contaminant benzene was selected as the target contaminant, and the GM was studied and analyzed under three different placement conditions. To investigate the effect of percolation fluid head on the one-dimensional transport of contaminants, Based on the semi-infinite boundary condition assumption, one-dimensional transport model of organic contaminants in composite vertical cut-off wall with defective high-density polyethylene geomembrane is established and solved numerically. The influences of GM pore ratio, GM placement position, and the contact level between GM and soil-bentonite cut-off wall on the migration law of pollutants are analyzed by the relative pollutant concentration, breakthrough time and contaminant flux. The following conclusions were mainly drawn:(1) Compared with the defect-free geomembrane, the service life of composite barriers with the defective geomembrane is significantly reduced. When the hole frequency increases from 5 to 25 and 50, the service life decreases by 55% and 65%, respectively.(2) The results show that the quality of the liner–soil contact significantly affects the flux of contaminants in the vertical cut-off wall. Specifically, compared with excellent contact conditions, the breakthrough time is respectively shortened by 39% and 65% under good and poor contact conditions, respectively. This influence on the transport behavior of contaminants cannot be ignored, and it is recommended that the construction process carefully control the contact conditions to ensure good performance.(3) The choice of the geomembrane position has limited impact on the transient flux of contaminants, but it does affect the total flux of pollutants over a certain period of time. For example, when benzene is the target contaminant, the total contaminant flux is the smallest when the GM is inserted inside the soil, and it is the largest when the liner is outside the soil.(4) Increasing the thickness of the cut-off wall can effectively extend its service life and improve its anti-contaminant effect. When the barrier thickness is increased from 0.4 m to 0.6 m and 0.8 m, the breakthrough time increases by 165% and 307%, respectively.(5) An increase in the hydraulic head of the leachate can accelerate the one-dimensional transport process of organic contaminants and significantly increase the outflow boundary flux. When the hydraulic head of the leachate is increased from 0 m to 0.1 m, 0.3 m, and 1 m, the breakthrough time is shortened by 37%, 71%, and 83%, respectively. Therefore, it is necessary to control the hydraulic head difference of the leachate in actual engineering to ensure the service life of the composite barrier.


The type of additive, its concentration, and the distribution between the surface and the volume of SnO2 crystallites have a significant effect on semiconductor gas sensor characteristics, namely sensitivity and selectivity. This review discusses the recent approaches to analyzing the composition of SnO2-based nanocomposites  and systematizes experimental data obtained using a set of analytical methods for studying the concentration of additives on the surface and in the volume of SnO2 nanocrystals. The benefits and drawbacks of new approaches to the high-accuracy analysis of SnO2-based nanocomposites by ICP MS and TXRF methods are discussed.Tin dioxide has huge potential and is widely studied and used in different fields, including as a sensitive material in semiconductor gas sensors. The specificity of the chemical activity of tin dioxide in its interaction with the gas phase is achieved via the immobilization of various modifiers on the SnO The pentavalent Sb and Nb, which are close to Sn4+ in ionic radius, exhibit donor properties and increase the concentration of free charge carriers when replacing Sn4+ cations in the SnO2 crystal lattice, as well as fluorine F− anions when replacing oxygen O2− anions.Tin dioxide SnO and WO3 ) with a  and WO3 ,5,6, inc and WO3 ,10,11,12 and WO3 ,14,15,16 and WO3 ,20,21,22 and WO3 , transpa and WO3 ,26,27,28 and WO3 ,32,33,34 and WO3 ,36,37, c and WO3  and meta and WO3 , catalys and WO3 , and che and WO3 ,42,43,442 in air is necessary to ensure long-term functioning at the elevated operating temperatures that are usually realized when detecting gases; a large specific surface area is needed to increase the proportion of material in direct contact with the gas phase; the reactivity of the surface determines the possibility of the adsorption of the target gas molecules and the occurrence of the reactions responsible for the sensor response formation; and a suitable level of electrical conductivity should make it possible to register the changes when interacting with gases, both electron donors and acceptors. Discussing the use of SnO2-based materials for gas sensor applications, it is worth noting that the phase composition, the chemical composition of the surface, the spatial distribution of the components, and the real structure of the materials are determined by the synthesis conditions. In turn, these characteristics determine the reactivity of the materials and the mechanism of their interaction with the gas phase; the concentration and mobility of the charge carriers; and, consequently, the sensor parameters, namely sensitivity, selectivity, and stability. The specificity of the chemical activity of tin dioxide in the interaction with the gas phase is achieved via the immobilization of various modifiers on the SnO2 surface: clusters or nanoparticles of precious metals and their oxides  or transition metal oxides  /[Sn] ratios prepared from appropriate mechanical mixtures of oxides were used as reference materials.The reliability of determining the additive concentration at the level of 1–5 wt.% by the EDX method is often questionable. For example, in , to studmate. In , 0.5, 1,r method ,79. Therr method , for SnOfied. In , for a cThe analysis of the phase composition of nanocrystalline materials is a difficult task because of the significant broadening of the diffraction maxima; furthermore, traditional X-ray diffraction studies require the use of additional methods.2-based nanocomposites, the crystalline phase containing the additive is often detected only at a sufficiently high concentration of the introduced additive and high annealing temperatures; in other cases, it is possible to form a solid solution and/or segregation of the amorphous phase containing the additive on the surface of the SnO2 crystallites. The implementation of one or the other option is determined by both fundamental reasons—for example, the difference in the ionic radii of Sn4+ (0.69 Å) and the additive’s cation Mn+—and the synthesis conditions—the method of introducing the additive, the concentration of the additive, and the temperature treatment. Based on the values of the ionic radii of metal cations in an oxygen octahedral environment /[Sn] = 0, 5, 10, and 15 mol.%, the unit cell parameters were analyzed by Rietveld refinement. It was found that when the [Ni]/[Sn] ratio was set at less than 10 mol.%, the unit cell parameters decreased with the increase in the Ni2+ concentration. However, for the sample with [Ni]/[Sn] = 15 mol.%, the unit cell parameter increased. The authors attributed such a change in the unit cell parameters to the achievement of the Ni2+ solubility limit in the form of substitution defects in the SnO2 structure. Unfortunately, there was no information in the article about the Ni2+ concentration in the SnO2 bulk; however, it was indicated that the actual Ni content in the samples determined by the XPS method varied from 1.8 to 6.3 mol.%. Given that XPS has a small depth of analysis  on a diffractogram of a mixture containing 50 wt.% of components. The sensitivity of the analysis varies for different phases, and the minimum detectable concentration is 5–15 wt.%. This approach is rarely used /[Sn] = 1 at.%) obtained by SnO2 impregnation with Mn(acac)3 and subsequent thermal annealing /[Sn] ratio of about 2 at.%) obtained via the hydrothermal method /[Co2+] ratio decreased with an increased total cobalt concentration. For cobalt-doped SnO2 nanobelts prepared by the chemical vapor deposition method /[Sn] = 1 and 10 mol.%, respectively. Thus, although the manganese was introduced as a surface modifier via the impregnation route, there was a doping effect caused by the redistribution of manganese between MnOx surface segregation and the SnO2 crystal structure. The manganese cations introduced in the SnO2 lattice acted as electroactive additives. Surface MnOx segregation had a significant influence on the sensor properties of the SnO2/MnOx nanocomposites. The presence of manganese in the total concentration of [Mn]/[Sn] = 1 mol.% increased SnO2 sensitivity towards CO and prevented signal inversion when detecting NO.SnOnnealing  with var2 matrix, followed by the analysis of the obtained solutions by TXRF and ICP MS methods, allows one to determine the additive concentrations on the surface and in the volume of SnO2 nanocrystals with high accuracy. It should be noted that, despite the proposed approaches to the decomposition of the SnO2 matrix in a mixture of acids using an autoclave, the dissolution conditions, namely the ratio of acid concentrations and the temperature regime, must be adapted to a specific material. This time-consuming stage complicates the analysis procedure. An alternative is the use of multielement TXRF for the analysis of suspensions of undisturbed nanocomposites and the SnO2 matrix after flushing additives from the surface. The selection of an internal standard for quantitative calculations makes it possible to reproducibly determine the concentration of the additive at the level of 1 wt.%.A detailed and thorough characterization of new nanocrystalline oxide materials used as a sensitive layer in semiconductor gas sensors is a necessary basis for reliably establishing the relationship between synthesis conditions, composition, structure, and sensory parameters (sensitivity and selectivity) in detecting gases of various natures. Whereas the term “composition” is complex and includes the gross quantitative elemental composition, phase composition, surface composition, electronic state of additives and main components, and distribution of additives between the volume and the surface of the metal oxide crystallites, to determine each of the abovementioned constituents, it is necessary to choose an adequate method of analysis. Besides this, the methods for determining the composition of nanocrystalline materials have a number of features. Given the small particle size and complex distribution of the additive in thin near-surface layers, the characterization of nanocomposites should be carried out using complementary methods. Along with X-ray diffraction, important information about the structure and phase composition of such systems can be obtained by scanning and transmission electron microscopy, electron diffraction, Raman spectroscopy, and Mössbauer spectroscopy. Traditional methods of surface investigation (Auger electron spectroscopy and X–ray photoelectron spectroscopy) also provide information averaged over a layer of 2–2.5 nm, which is comparable to the minimum diameter of crystal grains of 3 nm. These methods require the use of high vacuum, which creates additional difficulties in result interpretation. The approach based on the selection of a reagent for transferring an additive immobilized on the surface of tin dioxide to a solution without dissolving the SnO


A lamb of the same age with MAs in the 1:8 titer was 100% protected from infection with the field PPRV. Therefore, it is recommended that lambs of the Kazakh fine-wool breed be immunized from the age of 14 weeks or older to avoid a period of susceptibility.In this article, we first assessed peste des petits ruminants (PPR) antibodies in vaccinated pregnant ewes of Kazakh breed fine-fleeced immunized with the PPR vaccine and the duration of maternal immunity in their lambs. Ewes in the last trimester of pregnancy and gestation were immunized with a vaccine from the Nigeria 75/1 strain of the PPR virus (PPRV) produced by the Research Institute of Biological Safety Problems (RIBSP), Kazakhstan. Serum samples from lambs born from vaccinated and unvaccinated ewes were collected a week after birth and at intervals of 7 days for 18 weeks after birth. Serum samples collected from lambs were tested for PPR antibodies using competitive ELISA and virus neutralization test (VNT). Maternal antibodies (MAs) in lambs born from vaccinated ewes were detected for up to 18 weeks, with a tendency to decrease starting at week 14, and by the end of the experiment receded below the protective level (<1:8). In the blood serum of a 14-week-old lamb with MAs (1:8), post vaccination with a field dose (10 Morbillivirus genus in the Paramyxoviridae family [Saiga antelope, which are susceptible to the PPR virus. However, a serological study conducted in Kazakhstan in the period from 2012 to 2014 did not reveal Saiga antelopes seropositive for PPR [Peste des petits ruminants (PPR) is a highly contagious, infectious viral disease of small ruminant species that is caused by the peste des petits ruminants virus (PPRV), the prototype member of the e family . The dise family . Despitee family . Currente family . Five yee family ,5. Sincee family ,7. These for PPR .To date, due to the outbreak of PPR in Mongolia, the regions of Eastern Kazakhstan are at risk of PPR infection.To achieve PPR eradication, which is targeted for 2030, a PPR Global Control and Eradication Strategy (PPR GCES) was developed, based on a progressive reduction in PPR incidence and spread through targeted vaccination .Within the territory of the Republic of Kazakhstan, annual routine vaccination of small ruminants against PPR is carried out in border regions in order to prevent the introduction of PPR from neighboring countries that are disadvantaged by this disease. In Kazakhstan, live attenuated vaccines are mainly used for the prevention of PPR, which create 1-year immunity against PPR.To increase the immunogenicity of the PPR vaccine, we developed a live vaccine based on the Nigeria/75/1 strain. The live vaccine from the Nigeria/75/1 strain is the most widely used PPR vaccine approved by the OIE . It has There are few reports on the duration of persistence of maternal antibodies in lambs/kids born from ewes vaccinated against PPR . MaternaTo avoid negative consequences when immunizing young lambs and to determine the optimal age of lambs for vaccination against PPR, we studied the persistence of maternal antibodies in lambs born from ewes of Kazakh breed fine-fleeced vaccinated against PPR.In the southern regions of Kazakhstan, sheep mating occurs more often in the months of October and November, and lambing occurs most often in March and April. In this regard, in September, we purchased sheep of Kazakh breed fine-fleeced of either sex . All animals were dewormed by oral administration of albendazole. Food and water were available in unlimited quantities throughout the experiment. The animals were labeled and kept in isolation in the RIBSP quarantine zone for 30 days. Body temperature was regularly measured in the animals, and blood serum was collected to determine the presence of specific antibodies to PPRV. Detection of antibodies to PPRV in sheep sera was performed using a virus neutralization test (VNT) [Ewes in the third trimester of pregnancy were used for the research. Pregnancy periods in ewes were determined using ultrasonography. Estrus synchronization in ewes was not performed; therefore, as soon as the lambs were born, they were included in experimental studies. Newborn lambs were kept together with their mothers so that they could suck colostrum freely.Experimental studies were conducted in compliance with international and national ethical standards. The protocol was approved by the Ethics Committee for Animal Experimentation at the RIBSP (Permission number: 2908/22).3 TCID 50/mL). Four healthy ewes in the 3rd trimester of pregnancy were used as control animals (unvaccinated). All of the vaccinated and unvaccinated ewes were monitored daily for clinical signs of PPR, and rectal temperature was measured for 21 days post vaccination (dpv).Out of 15 females, 10 became pregnant. Ewes (n = 6) in the 3rd trimester of pregnancy were immunized with PPR vaccine (Nigeria 75/1 strain) produced by the RIBSP, Kazakhstan. Ewes were immunized subcutaneously with a single field dose of the vaccine , ID.vet, Montpellier, France) was used [Blood sera of experimental animals were additionally examined for the presence of antibodies in c-ELISA. As an additional test for detecting anti-PPRV antibodies to nucleoprotein (NP) in the blood sera of experimental animals, a c-ELISA kit . Aliquots of RNA were stored in a freezer at a temperature of −70 °C until tested.All types of samples were analyzed by real-time RT-PCR to detect the presence of viral nucleic acid with the RT-qPCR kit , using the Applied Biosystems 7500 system .3 TCID50/mL. On 0, 7, and 14 dpv, blood samples were collected to determine the titer of serum antibodies.When the first two newborn lambs reached the age of 14 weeks, they were used for research to assess the effectiveness of passive immunity. Before starting the study, the lambs’ blood sera were tested for the presence of maternal antibodies in c-ELISA. The titer of maternal antibodies circulating in the blood sera of these lambs was 1:8. One of them was subcutaneously immunized with a vaccine at a dose of 1.0 × 10The second 14-week-old lamb was used to assess protective passive immunity.As unvaccinated animals, 2 lambs of 14 weeks of age were used, born first from unvaccinated ewes.5.0 TCID50). After control infection, experimental and unvaccinated animals were observed for 14 days with daily measurement of body temperature, sampling of swabs  and blood, as well as the identification of clinical signs of PPR. Clinical signs of PPR detected in all animals were evaluated in points [On 14 dpv, 2 experimental lambs (one unvaccinated and one vaccinated) born with maternal antibodies and 2 unvaccinated lambs were inoculated with the control strain of PPRV (Kentau-7)  subcutann points ,17. Durip ≤ 0.05 indicated that there was a significant difference between the data obtained. The difference in efficiency between the groups was compared using a one-sided Fisher exact criterion for two proportions at an alpha level of <0.05.During the statistical analysis, GraphPad Prism software (version 8.0.1.) was used. Differences between antibody titers and between temperature and clinical parameters of experimental and control animals after immunization and infection with a control virus were determined using bilateral ANOVA tests. The value of 2, which disappeared within 4–5 days. During the observation period (21 dpv), the body temperature of the ewes fluctuated in the range of 38.5–39.8 °C , all pregnant ewes were seronegative for PPRV antibodies. In the first week post immunization, the average titers of neutralizing antibodies (NAs) increased to 1.6 log2. On 14 dpv, the level of NAs to the PPRV in pregnant ewes was 5.6 log2, and the indicated antibody titer increased to 7.2 log2 on the 21st day post vaccination . UnvacciAll samples of blood sera of pregnant ewes were negative before immunization with the vaccine against PPRV and had a ratio of S/N > 150%. Within 7 dpv, the S/N ratio in pregnant ewes was 87%. Protective titers of antibodies to the PPRV were found in 43% of animals. In 32% of animals, the titer of the produced antibodies exceeded the recommended threshold of S/N values (60%) for positive samples. In the remaining 25% of pregnant ewes, the results of c-ELISA were doubtful (50–60%). On 14 dpv, judging by the antibody titers, 92% of pregnant ewes were protected from PPRV, and the S/N ratio was 46%. The lowest S/N% value in vaccinated ewes (18%) was recorded on 21 dpv .A total of 10 lambs were born from vaccinated ewes at different times. In all lambs (n = 6) born from vaccinated pregnant ewes, the level of MAs produced was in the range of 5.5 log2 and 7.2 log2, and provided 100% humoral protection of the offspring from the PPRV up to the 14th week. Starting from the 14th week, there was a gradual decrease in MAs titers below the protective level (<1:8), and by the end of the 18th week, the MA titers in lambs were in the range from 1.0 to 2.25 log2 . UnvacciBlood serum samples were collected from all lambs a week after birth to assess the level of MAs. In all collected samples of lambs’ blood serum, the S/N ratio was lower than <50%, which indicated a high level of passive immunity in newborn lambs.p > 0.05). At the same time, the average value of S/N was in the range of 20–55% , the titer of NAs in the vaccinated lamb was 4.0 log2. In the first week post vaccination, the titer of NAs increased to 4.7 log2. At 2 weeks post vaccination, the level of NAs was 5.4 log2. PPRV antibodies were not found in the blood of the unvaccinated lambs.PPRV genome was not detected in blood samples and smears of lambs born with MAs . SimilarIn contrast, according to the results of RT-qPCR analysis, all types of samples taken from challenged lambs turned out to be positive . In chal2 at the injection site of the vaccine, which resolved within 4 dpc. However, the results of the RT-qPCR analysis were negative.Vaccinated at 14 weeks of age, the lamb was not ill with the manifestation of clinical signs of the PPRV. However, within 2 days (on the 3rd–4th day), he had an increase in body temperature to 40.0 °C, which then normalized ; at the 2 was observed in the lamb at the injection site of the vaccine, which resolved within 6 dpc. All types of samples and swabs collected from an unvaccinated lamb as a result of PCR analysis were negative.An unvaccinated 14-week-old lamb born with MAs post challenge with the control strain had an increase in rectal temperature to 40.2 °C on the 3rd dpc, which normalized on the 6th day of the control test; at this stage , the lamOn 3 dpc, challenged lambs had an increase in rectal temperature, which reached up to 40.8 °C on 5 dpc . Pyrexia2 was observed at the site of vaccine administration. On the 5th–6th dpc in intact lambs, nasal discharge became thick, purulent and yellow-greenish in color. In both challenged lambs, the gums became hyperemic. On the 7th–8th dpc wheezing was heard in the breasts of the lambs, while they had no appetite and were apathetic and sluggish, and liquid pus accumulated in the corners of the eyes (acute conjunctivitis). In addition, both lambs had loose stools, estimated at 3 clinical points , and a pink spot with a diameter of 2.0 cml points . At 10 dl points . After el points .During the necropsy and examination of the internal organs of the euthanized lambs, changes were found in the lymph nodes , small intestine and lungs. The lymph nodes were enlarged a–c. CataIt is known that proper vaccination of ewes before mating is of great importance for the immune system of the offspring, since vaccines stimulate the production of MAs, which then pass into colostrum and provide newborn lambs with additional passive protection.Conversely, vaccination of newborn lambs causes an insignificant immune response, because their immune system is not yet fully developed and cannot produce antibodies until the third or fourth week of life. In addition, it is known that vaccines administered to lambs up to 2 weeks of age bind MAs, and the young body remains defenseless.Therefore, determining the optimal age for vaccination of young animals, which will come at a time when the level of MAs will significantly decrease and the young body will be able to develop its own protective adaptive immunity in response to the introduction of the vaccine with the formation of immunological memory, is of great importance. It should be noted that the formation of maternal immunity in offspring largely depends on the breed of the animal and the effectiveness of the strain used in the manufacture of a vaccine applicable for the immunization of pregnant animals.Previously, in Kazakhstan, a live attenuated vaccine from the G45-MK strain was used to prevent PPR, which protected immunized animals from PPR for 1 year. Due to the short duration of immunity in vaccinated animals after immunization with a vaccine against PPR from the G-45MK strain, RIBSP employees decided to use a highly immunogenic strain (Nigeria 75/1) as the main agent for the development of a vaccine against PPR.Although the Nigeria 75/1 strain is the main agent recommended by the OIE for the development of a vaccine against PPR, there is currently limited information on the optimal age at which lambs should be vaccinated with this vaccine.These studies were devoted to assessing the duration of maternal immunity in lambs born from pregnant ewes of Kazakh breed fine-fleeced, immunized with a vaccine from the attenuated Nigeria 75/1 strain.The post-vaccination results for pregnant ewes obtained by us proved the effectiveness of the vaccine used for sheep of the Kazakh breed fine-fleeced, since immunized pregnant ewes had protective antibody titers formed on day 14 (SN ≥ 1:8) to the PPRV . In prevLambs born from sheep of Kazakh breed fine-fleeced immunized with a vaccine from the Nigeria 75/1 strain after receiving a sufficient amount of colostrum had protective levels of maternal antibodies against PPR for 14 weeks. From week 14 to the end of the experiment (18 weeks), a decrease in antibody activity was observed, and at week 18, all lambs had titers <1:8 . In thisSimilar results were reported in a previously published work by Bodo et al. (2006), where the authors recommend immunizing lambs born from Djallonké ewes in the interval from 11 to 14 weeks after birth .Markus et al. 2019) and Abdollahi et al. (2023), who conducted similar studies, recommend immunizing kids born from Kano brown and Saanen goats vaccinated with the Nigeria 75/1 strain at the age of 10 weeks ,20, whil19 and AbIt is known that for reliable protection of animals from PPR, the level of VNA in the blood serum of animals should be ≥1:8 ,24. SincIn a similar study conducted by Balamurugan et al. (2012) in a lamb immunized with the Sungri vaccine strain, protective titers of antibodies to the PPRV began to increase from the 21st day post vaccination (21 dpv) . It is pThe total clinical score calculated by us during the control trial using the field strain PPRV was for the experimental and control groups of lambs 2 and 41 , respectAt the same time, the lambs of the experimental group had a two-day increase in body temperature and pink spots on the site of the introduction of the vaccine, which disappeared by themselves within 4 dpc .However, the results of RT-qPCR analysis turned out to be negative when examining blood samples and swabs collected from an experimental group of lambs after vaccination and control infection .The unvaccinated lambs showed pronounced clinical signs of PPRV after the control test. In addition, all swabs and blood samples collected from the unvaccinated group of lambs were positive when examined using RT-qPCR . Due to p > 0.05). Although a minimum number of lambs were used to determine the effectiveness of the vaccine, the results obtained indicate that lambs born from a fine-fleeced Kazakh breed should be vaccinated from the age of 14 weeks or older.The results of this study once again prove the safety and effectiveness of the vaccine from the Nigeria 75/1 strain for pregnant ewes, since the vaccine did not affect the course of pregnancy in ewes of the Kazakh breed fine-fleeced, while all ewes were protected from PPR from 2 weeks post vaccination. The maternal immunity formed in lambs born from vaccinated sheep of the Kazakh breed fine-fleeced persisted until 14 weeks after birth, with slight fluctuations in antibody titers (It is important to note that, despite the limited number of animals in our study, the results offer opportunities for careful design, meticulous data analysis, and collaboration. By implementing these strategies and viewing this limitation as a stepping stone for future research, we can work toward eliminating this constraint and gaining more robust insights in the future.Analyzing the results we obtained in this study, we came to the conclusion that during routine vaccination against PPR, lambs born from sheep of Kazakh breed fine-fleeced should be immunized from the age of 14 weeks or older to avoid a period of susceptibility in lambs to the PPRV. Since the same vaccine against PPR can cause different immune reactions in different breeds of sheep and goats, it is necessary to conduct further studies on other breeds of sheep and goats living in Kazakhstan in order to determine the appropriate period of immunization of small cattle with a vaccine from the Nigeria 75/1 strain.