It aims to improve and increase the productivity of technologies for the production of artificially carbonated building materials and products. Soda production wastes, limestone dust and finely dispersed limestone dust were used as the research objects. Secondary raw materials have been investigated using modern methods of phase composition and granulometry test. Intensive methods of production of accelerated carbonation of systems consisting of soda wastes were tested using multi-parameter optimization methods. The effects of recycled lime materials on the strength and hydrophysical properties of the obtained material were determined. The secondary raw materials effect depended on the composition of the raw mixture, molding conditions, CO2 concentration applied to the carbonate curing chamber, and the duration of exposure to environments with high CO2 content. It was found that the most effective way of providing accelerated carbonation curing of construction materials and products is a combined carbonation method, combining the principles of dynamic and static methods. It was concluded that the optimal CO2 concentration in the gas-air mixtures used for carbonate curing is 30%–40%.The article is dedicated to the research and development of intensive methods for curing products by capturing and binding CO The global environmental problems of climate change as a result of human impacts on nature have been firmly established as the most internationally discussed issues (Conference of Parties (COPs) in Warsaw (COP-19 in 2013), in Lima (COP-20 in 2014), in Paris (COP-21 in 2015), and most recently in Marrakech (COP-22 in November of 2016). The increasing concentration of greenhouse gases in the atmosphere at the current stage of economic development requires the development of new products and production methods characterized by lower CO2 into the atmosphere is the construction materials industry, which is in second place after the energy sector in terms of global CO2 emissions. Thus, the production of Portland cement and other binders alone accounts for up to 8% of the world’s anthropogenic CO2 emissions [2 sequestration is one of the most important technical challenges of our time [One of the branches of industry that emits a significant amount of anthropogenic COmissions ,2,3,4. Iour time .2 can be used both as an effective additive of cement concrete curing accelerator and as the main raw material component [2 and bind it into stable compounds.It is noteworthy that at the same time, it is the construction industry that has significant potential in terms of creating technologies for the production of various materials and products that use carbon dioxide in their manufacturing process. It is shown in ,7 that Component ,9,10. Re2 binding have been revealed, scientific and technological bases for introduction of the received results in the industry have been developed [2 have been issued [A significant reserve of raw materials in the production of building materials and products hardening due to carbon dioxide are various wastes and industrial waste products, which at certain technological processing can exhibit bindering properties and enter into chemical interaction with carbon dioxide, forming an artificial stone. As a result of numerous research studies ,13,14,15eveloped , and morn issued .2 emissions into the atmosphere to significantly increase the environmental friendliness of the technology, it is transferred to the "low-carbon" class.One of the promising secondary raw materials for the production of carbonate hardening building materials is the waste generated in the production of soda ash. The chemical process of soda ash production using ammonia technology is based on five reactions, one of which is the production of calcium oxide and carbon dioxide as a result of carbonate rock cooking in lime kilns . As a reForced carbonation is an active curing process and allows the production of materials with high physical and mechanical characteristics within a short time period (1–3 h) ,21,22. HIn this regard, the main idea of the performed research work is to research and develop intensive methods of forced carbonation of the systems consisting of soda production wastes—lime dust and finely dispersed limestone, and their influence on the formation of the basic properties corresponding for structural building materials and products, depending on the various formulation and technological factors. For this purpose, a series of experiments have been conducted, the main results of which are presented in this article.The materials used for scientific research were lime dust mechanically precipitated in cyclones and bag filters of mine lime kilns that calcin limestone. Finely dispersed marble limestone with fraction up to 5 mm, formed in the process of crushing and sorting the initial rock into a working fraction sent to the shaft kiln for cooking, was also used.The activity of lime dust, determined by standard methods of lime testing, was 45%, humidity 0.6% wt., temperature and quenching time are 41 °С and 47 min, respectively.The phase composition was determined using Perkin Elmer’s STA 8000  high-temperature synchronous analyzer (USA), in the temperature range of 30–1000 °С, at a heating rate of 10 °С/min in a nitrogen environment. The particle size of the investigated materials was determined on the laser analyzer HORIBA LA-960 .2 and CaCO3. Quantitative changes in the phase composition of lime dust depending on the conditions of its pre-preparation were investigated using synchronous Thermogravimetric and Differential thermal analysis (TG-DTA) analysis under a dynamic nitrogen atmosphere. Samples were tested in their natural state and after quenching under different conditions, in order to determine the presence of calcinated CaO particles. Samples were dried before testing. Changes in the content of the main phases in lime dust under various conditions of its preliminary preparation are presented in The lime dust is factory stored and stored in bulk in an open fenced area. It is natural to believe that under such storage conditions, a portion of the free СаО contained in it is extinguished and transferred to Ca(OH)2. Equivalent to CaO, this is 30.5%. TG-curves of freshly slaked lime dust samples show that the Ca(OH)2 content is increasing, however, it can be seen from the CaO content that there is still a significant amount of free calcinated CaO particles in the composition. After quenching and the additional maintenance of products of quenching of lime dust during 120 and 420 min, and also after boiling and maintenance during 420 min, according to the data of TG-DTA curves, the quantity of Ca(OH)2 with increase in time of maintenance increases to 55.1%, and after boiling, increases up to 59.5%. Based on the results of the thermal analysis, the amount of calcinated CaO particles in the lime dust is about 7%. According to the analysis, lime dust is found to be one-third composed of calcium carbonate—uncalcinated limestone particles. In addition, lime dust in its composition contains admixtures of silica (SiO2) and uncalcinated hard coal, manifested on thermograms in the form of exothermic effects in the temperature range of 350–400 °C.The analysis of experimental data on changes in the mineralogical composition of lime dust depending on the conditions of its preparation show that in its natural state lime dust is in a hydrated state and contains about 40% Ca(OH)Determination of the size of lime dust particles in the quick and slake state  by laserAs finely dispersed limestone in the work used by-products of crushing and sorting of limestone Balaklava deposit (Crimea) fraction to 5 mm, formed during the crushing and sorting of the original rock to the working fraction sent to the mine kiln for cooking. The main properties and content of the main rock-forming chemical compound calcium carbonate limestone are presented in Limestone from the Balaklava deposit belongs to nummulite partially recrystallized (metamorphosed) limestone and is a sedimentary dense and sufficiently strong rock. The thermogram of limestone  has one Liquid high-pressure carbon dioxide in cylinders was used as a source of carbon dioxide in laboratory studies.Research studies were carried out on the cylinder samples made by a method of semi-dry pressing of the molding mixtures, consisting of thoroughly mixed in a speed mixer of lime dust and finely dispersed limestone, passed through a sieve with the size of mesh 1.25 mm. The water content of the molding mixtures was 10% wt. These values are justified by the results presented in ,22,25. T2 in it [2 gas and air mixtures.The forced carbonation of testing samples was carried out in the carbonation unit with automatic control and maintenance of the required concentration of CO2 in it . The uni0, bi, bij, bii is correlation coefficients determined as a result of mathematical and statistical processing of experimental data; zi, zj is the value of variable formulation and technological factors.Research studies of complex influence of the composition of a raw mix, factors of reception, and also modes of the accelerated carbonation of pre-production of testing samples were spent by means of statistical methods of mathematical designing of the experiment ,28. CentThe significance of ES model correlation coefficients was determined with the help of the Student’s criterion; the second-order equation checked the adequacy of the object description by the Fisher’s F-criterion.Two four-factor experiments differing only in the method of forced carbonation—dynamic (cyclic) and static—were implemented.2 environment of a certain concentration. The rarefaction in the chamber was 5000 Pa, the prepared in advance to the required concentration gas and air mixture of CO2 was fed into the chamber from a buffer tank. The gas, seeping through the pores of the product, returns to the buffer tank, where it is brought to the desired concentration by feeding the required amount of CO2. The duration of one cycle was 180 s.The principle of the applied dynamic method of carbonation implied accelerated carbonation of the lime binder within several cycles. One carbonation cycle included several consecutive operations: vacuumization of the sample chamber, holding under conditions of rarefaction, carbon dioxide supply to the carbonation chamber, holding the samples in COThe statistical method of carbonation was based on storing testing samples in carbon dioxide gas and air environment, without creating the resolution in the carbonation chamber. Duration of carbonation of testing samples corresponded to the duration of carbonation under the dynamic method.2 (z1), the forming pressure of pressing the testing cylinder samples (z2), the content of lime dust in the lime-lime composition equivalent to Ca(OH)2 (z3) and, directly, the modes of forced carbonation, the number of cycles and time of exposure to CO2 on the testing samples (z4). The designing conditions for the experiment are presented in The choice of factors in the experiment was made, taking into account the conclusions obtained in the analysis of the structure formation and properties of artificial stone based on lime carbonate hardening ,22,25. Tc), average density (ρo), water resistance (KS), water absorption by mass (Wm) and carbonated layer thickness (δ).Main parameters of testing samples were compressive strength  and static (2) methods are presented in The correlation coefficients of ES models, obtained as a result of statistical processing of testing data, are presented in 2) and lime dust content (z3), then in the static method (model 2), along with the main factor z2, the factors responsible directly for the process of carbonation curing, such as the concentration of CO2 (z1) and carbonation time (z4), become more decisive.The estimation of the influence of separate technological factors shows that the importance of their influence on the formation of properties of materials based on lime carbonation hardening depending on the chosen method of production of artificial carbonation is different. So, if the dynamic method of carbonation (model 1), the most influencing factors can be called the factors for obtaining the testing samples, i.e. pressure pressing , in the composition of forming mixtures. Most likely, water resistance depends on the degree of carbonation contained in them Ca(OH)2, which under the above conditions and under accepted time factors, is characterized by maximum KS values.Water-resistance is mainly provided by carbonated cylinder samples obtained at forming pressures up to 10 MPa, as well as samples containing a minimum amount of lime dust (Ca(OH)S values corresponding to water-resistant materials are achieved earlier. For example, at the minimum content of lime dust is known ,29,30,312 penetration differs depending on the modes of forced carbonation of the cylinder samples. Thus, in samples carbonated by the dynamic method, the inner non-carbonated part after spraying phenolphthalein alcohol solution on it has a pale color in comparison with samples carbonated by the static method. This may indicate a deeper penetration of the carbon dioxide in forced carbonation in a dynamic (cyclic) mode. It should be noted that despite clear boundaries, the carbonated layer does not peel off the uncarbonated part of the sample, representing a solid heterogeneous conglomerate.A visual analysis of the sample also allowed one to determine that at close values of δ depth of COAs can be seen from the presented experimental calculation results of the study, it is unambiguously difficult to interpret them. It makes sense to consider the process of formation of the basic properties of carbonate hardening materials, depending on the intensity of their forced carbonation more complex, combining the maximum number of factors.The graphical processing of experimental and calculated data of models of the formation of compressive strength of investigated lime-liming systems on the basis of lime dust, depending on the simultaneous influence of varying factors at various modes of carbonation is presented in 2 concentration in the gas and air mixture up to 50%; a further increase in CO2 concentration up to 65% practically does not affect the change of Rc. A certain pattern of the dependence of Rc testing samples on the forming pressure of the pressing is traced. It can be assumed that with a further increase in the concentration of CO2, the compressive strength will be reduced due to the developing corrosion and dissolution of newly formed CaCO3 crystals, in accordance with the study of Cizer et al. [c values decrease, which, is explained by a denser structure of the material obtained at such high pressing pressures of the raw mix. Consequently, longer exposure times are required in environments with higher CO2 concentrations. Thus, this fact of reduction of Rc proves that carbonation component, which forms the future structure of artificial stone from calcite crystals, actively participates in the formation of strength indices of pressed materials, the hardening of which is organized by carbonate type [With the dynamic method of forced carbonate hardening see a, the cor et al.  Accordinate type ,33,34. 2 in the gas and air mixture fed into the carbonation chamber. This phenomenon shows that the acceleration of the lime carbonation reaction by actively seeping CO2 through the samples, simulated in the experiment as a dynamic mode of carbonation, firstly, leads to a sharp formation of a large amount of water in the system, which clogs and closes the pores in the material, and complicates the diffusion of CO2 in the pores of the material, and secondly, it can create conditions for the emergence in the system of aggressive carbon dioxide and the beginning of the dissolution and corrosion of calcite crystals of the newly formed carbonate structure [With the static method of treatment of compositions with carbon dioxide see b, the retructure ,35,36,372 and further conducting the process in a static mode, maintaining a given concentration of CO2.Estimating the obtained ES samples of forced carbonate hardening of samples on the basis of lime dust and limestone, it can be concluded that the most appropriate way to carry out the accelerated carbonation of materials based on lime, may be a combined method of artificial carbonation, which consists in creating a pre-discharge in the carbonation chamber, the subsequent supply of gas and air mixture of CO2 in the gas and air mixture at different methods of carbonation, is presented in The analysis of changes in compression strength depending on the content of lime binder, forming the pressure of pressing and concentration of CO2 concentration of more than 40%–50% of the compressive strength practically does not change, and with the growth of molding pressure of pressing increases the limit concentrations of CO2, at which Rc practically does not change. Thus, for testing samples manufactured with a pressing force of 10 and 20 MPa, the maximum concentration of CO2 is 40%, and for samples pressed at 30 and 40 MPa—60%.The dynamic method of carbonation  shows th2 up to 15% wt. in their composition, there is some decrease of compressive strength, with increasing content of lime in the composition—the strength increases. It seems that this could be an error in program calculation. The strength at the content of calcium hydroxide in the moulding mixtures within 5% wt.–15% wt. changes insignificantly, and with an increase in the content of Ca(OH)2 in compositions over 15% wt., the strength increases markedly. It should be noted that the compressive strength of samples carbonated by the static method at increased pressing pressures (hyper-pressing) over 30 MPa is 25%–35% higher than that of similar samples obtained by the dynamic carbonation method. In the conditions of static carbonation  in testic is such that, with an increase in the number of cycles (more than 5) and molding pressure, the pressing growth of compressive strength is somewhat slowed down, due to difficult access from CO2 particles to Ca(OH)2 in the deep layers of the sample, due to the blocking pores of the material water released during the carbonation reaction Ca(OH)2.The study of the influence of the number of cycles in the dynamic method of carbonation on the change in compression strength of testing samples, presented in 2 supply more than 45%.Compressive strength of samples at the static method of carbonation  in contr2. Increased factors such as molding pressure and lime content in samples, on the contrary, reduce the thickness of the carbonated layer, mainly due to the formation of a more dense initial structure of the material, which prevents the diffusion of CO2 [The formation of water-resistance of materials based on lime carbonation curing, as can be seen from the results obtained, depends on the formation of the carbonated layer, the thickening of which is facilitated by increasing the concentration and processing of samples in environments with a high concentration of COn of CO2 ,38,39,402 and the number of carbonation cycles also reduces the water absorption of samples and increasing the content of Ca(OH)2 in the raw mix increases the Wm indicator of carbonated material, impairing its hydrophysical properties.Water absorption by weight of carbonated samples determines the forming pressure of the pressing, with an increase in which the water absorption index decreases. Increasing the concentration of COs on the thickness of the carbonated layer, δ, from which it is seen that the material acquires the properties of water resistance (Ks ≥ 0.8) at δ ≥ 9 mm.As was found during the analysis of the research results, the water-resistance of the testing samples depends on the degree of the carbonation of the lime binder, which can be indirectly characterized by the carbonated layer of the samples. 2 under pressure. Their research showed that this resulted in a rapid increase in compressive strength, as well as in microstructure compaction. Ahmad et al. [2 steel slag paste. The gas was at a pressure of 0.1 MPa. They observed that the creation of CaCO3 in pastes reduced the amount of pores and thus improved their compressive strength. Studies carried out by Liu et al. [3S) paste, which is the leading phase in Portland cement. The samples were subjected to accelerated curing with carbon dioxide (4-bar pressure). The results showed that after 2 h of curing, the paste reached a compressive strength of 27.5 MPa and after 24 h up to 62.9 MPa, where the samples subjected to hydration at the same time reached 5.2 MPa and 8.6 MPa, respectively. Cement blended with ground volcanic ash subjected to carbon curing was investigated by Seo et al. [In their work, Ergenç et al.  showed td et al.  checked d et al. , Moropoud et al.  have obsd et al.  in theiru et al.  indicateu et al.  tested to et al.  They obsIn this paper, the thickness of the carbonated layer, δ, was determined by spraying a 1% alcohol solution of phenolphthalein on the cleaved surface of the test sample see . This me2 in the carbonation chamber is within 30%–40%. One of the necessary conditions for the process of forced carbonation in the manufacturing of building materials and carbonate hardening products is to ensure the intensive removal of moisture by carbonation chambers. Moisture should be removed both from the samples and from the chamber itself, by "aerating" the chamber through the flow of a gas-air mixture with a constant CO2 concentration.As a result of research studies of dynamic and static modes of carbonation of testing, it has been established that the most effective way of the accelerated carbonation hardening of the building materials and products, is a combined method of carbonation. This combination consists of dynamic and static methods. The essence of the combined method is to create a preliminary discharge in the carbonation chamber; the subsequent supply of carbon dioxide gas and air mixture and further carbonation in a static mode, maintaining a constant concentration of CO2, is not effective at high concentration of carbon dioxide in a carbonation chamber (more than 50%). Optimal concentrations of CO2 in gas and air mixtures used to produce building materials and forced carbonate hardening products can be considered to be 30%–40%. Approximately, this concentration of carbon dioxide is found, for example, in the kiln and flue gases of coal-fired charcoal kilns and thermal power plants. Taking into account the fact that at high concentrations of CO2 defects develop in the structure of forced carbonated material, it is more appropriate to increase the carbonation time.The results of the present research studies have shown that the application of the accelerated methods of carbonation of materials on the basis of a binding component containing Ca(OH)


We have performed a quantum-mechanical study of a B2 phase of Fe Antiphase boundaries (APBs) are very frequently occurring extended defects in crystals containing ordered sublattices. They are at the interface of two regions of the same ordered phase which are shifted one with respect to the other. The shift is formed, for example, during ordering processes when two grains crystallizing from the melt have the origin of their lattices in a distance which is not a multiple of translational vectors of the superlattice. As the formation of the above described interfaces occurs at elevated temperatures when diffusion processes are sufficiently active, an intermediate disordered phase can form . Dislocations with Burgers vectors that are not translation vectors of the ordered superlattice can also create APBs at any temperature, as they move through an ordered phase .a where a is the lattice parameter of the 2-atom elementary cell of the body-centered cubic (bcc) lattice. It interrupts the chemical order of the first nearest neighbors (APB-NN or APB-B2 type). As deformation APBs, both types separate partials of superdislocations in Fe-Al materials [Our theoretical study is focused on APBs in Featerials ,5,6,7,8.aterials ,17,18,19aterials ,39,40,41aterials ,43 obseraterials ,45,46. Oaterials ,50,51,52Our research is focused on APB-NN (APB-B2) in a B2-phase Fei et al. . MurakamOur quantum-mechanical calculations were done with the help of the Vienna Ab initio Simulation Package (VASP) ,54. The The B2 phase of Fe concept  and gene concept ,63,64 , we consider properties of the A2 phase computed separately as a bulk as our model for the experimental thick layers. If we take the bulk APB-free B2 phase and bulk A2 phase as references and handle the atomic configuration in The calculated value equals to 0.083 J/mRegarding magnetic properties of the atomic configuration shown in Comparing the plots shown in Our theoretical results qualitatively confirm the interpretation of experimental findings published by Murakami et al.  that theOur results allow for obtaining a deeper insight into the actual mechanisms behind the observed phenomena and a better understanding of them. In particular, we clearly show that the local magnetic moments of Fe atoms decrease with an increasing concentration of Al atoms in the 1NN shell of the Fe atoms. This trend is in the case of the B2 phase clearly nonlinear when considering the whole concentration range of Al atoms see a. The deAnalyzing the structure of the B2 phase first, one half of its {001} atomic planes contains only Fe atoms and, consequently, all Al atoms are located in the other half of {001} atomic planes where the concentration of Al becomes much higher (60%) than the overall value of 30 at.% in the FeThe situation in the A2 phase is quantitatively very different. All of the atomic planes have on average the same Al concentration and it is only 30 at.%. Leaving aside local fluctuations, 30% is then also the average concentration of Al atoms in the 1NN shells of all Fe atoms. Considering the fact that the decrease of the magnetic moment is weaker for concentration of Al atoms below 50% (prior the onset of nonlinearly stronger reduction), the magnetic moments of Fe atoms in the A2 phase will be reduced less see a than thAnother insight obtained from our simulations of sharp APBs in the B2 phase is the theoretically identified relation between the average APB energy and the concentration of Al atoms in the two atomic planes adjacent to the APB interface. The simulated APB shift leads to the situation when these planes are formed by either two Fe-only planes or two Fe-Al planes (each containing both Fe and Al atoms). None of these APB-related atomic environments exists in the APB-free B2 phase. We have performed calculations of four different sharp APBs in the B2 phase a–c whichThe change of the Al concentration at the APB interfaces by the formation of the A2 phase to 45 at.% deserves further attention as it can be partly justified in the context of thermodynamic stability of the binary Fe-Al system. According to the thermodynamic assessment by Sundman and co-workers , the comThe thermodynamic perspective can help us to explain why the insertion of A2 phase between the two Fe-only atomic planes of the originally sharp APB in the B2 phase of Fecompound ). TherefHowever, the studied systems are not formed only by the two atomic planes adjacent to the APB interface. Regarding the formation of the A2 phase at the APBs, it should be noted that, according to our calculations, the energy of the A2 phase of FeR is the universal gas constant, i runs over different chemical species, i on a sublattice R) of the B2 phase amounts to 0.3365 and that of the A2 phase is equal to 0.6109. If the energy difference of 18.5 meV per atom is to be compensated solely by the difference in the configurational entropy, it would happen at the temperature of 784 K. The experimental B2–A2 second-order transition temperature is significantly higher, 1287 K [As the B2 and A2 phases exhibit different numbers of ordered and disordered atomic sites (sublattices), we use a generalized formula  derived, 1287 K , but theThe existence of the thermally-induced A2 phase at the APBs is really crucial for the increase of magnetism detected in experiments by Murakami et al. . The shaThe increase of the averaged magnetic moment of Fe atoms in the A2 phase by 17.5%  chemical species which decrease the magnetic moment of the magnetic elements. If this reduction of magnetism is enhanced by thermodynamically-driven formation of ordered sublattices, then the APBs offer a way of decreasing the level of order in the system and that results in a statistically higher probability of magnetic species to be in magnetically more favorable environment .We have performed an ab initio study of B2 phase of Fei et al.  who repo (2–3 nm ), our si 2–3 nm ,39). Thi. Thi70AlRegarding the formation of the A2 phase at the APBs, we link it to the energetics of atomic configurations occurring at both the sharp and A2-containing thermal APBs in the B2 phase of Fe


Global navigation satellite system (GNSS) can provide dual-frequency observation data, which can be used to effectively calculate total electron content (TEC). Numerical studies have utilized GNSS-derived TEC to evaluate the accuracy of ionospheric empirical models, such as the International Reference Ionosphere model (IRI) and the NeQuick model. However, most studies have evaluated vertical TEC rather than slant TEC (STEC), which resulted in the introduction of projection error. Furthermore, since there are few GNSS observation stations available in the Antarctic region and most are concentrated in the Antarctic continent edge, it is difficult to evaluate modeling accuracy within the entire Antarctic range. Considering these problems, in this study, GNSS STEC was calculated using dual-frequency observation data from stations that almost covered the Antarctic continent. By comparison with GNSS STEC, the accuracy of IRI-2016 and NeQuick2 at different latitudes and different solar radiation was evaluated during 2016–2017. The numerical results showed the following. (1) Both IRI-2016 and NeQuick2 underestimated the STEC. Since IRI-2016 utilizes new models to represent the F2-peak height (hmF2) directly, the IRI-2016 STEC is closer to GNSS STEC than NeQuick2. This conclusion was also confirmed by the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) occultation data. (2) The differences in STEC of the two models are both normally distributed, and the NeQuick2 STEC is systematically biased as solar radiation increases. (3) The root mean square error (RMSE) of the IRI-2016 STEC is smaller than that of the NeQuick2 model, and the RMSE of the two modeling STEC increases with solar radiation intensity. Since IRI-2016 relies on new hmF2 models, it is more stable than NeQuick2. The ionosphere is an ionized region with an altitude from 60 km to 2000 km. According to the distribution of ionospheric electron density by height, the ionosphere is generally divided into D (60~90 km), E 90~140 km), F1 (140~210 km), and F2 (over 210 km) layers from low to high. Evaluating total electron content (TEC) is important for characterizing the ionosphere. TEC is measured in electrons per square meter. By convention, 1 TEC Unit (TECu) = 40 km, F1The International Reference Ionosphere (IRI) and NeQuick models are two international ionospheric empirical models, which are widely used worldwide ,3. The IThe NeQuick model is a time-dependent, three-dimensional ionospheric electron density model . Based oTo compare and demonstrate the modeling accuracy of IRI and NeQuick, researchers have performed many studies. Cherniak et al.  analyzedThe observational data used in this study were the dual-frequency observational data from GNSS stations in the Antarctic. These stations include five IGS stations, six Polar Earth Observing Network (POLENET) stations, and four GNSS stations built by members of the Antarctic expedition. The distribution of all these stations is shown in TEC calculation formula for the carrier phase smoothing pseudo-ranges is shown in Equation (1) [Because the ionospheric delay of GNSS signals is inversely proportional to the square of the signal frequency, GNSS dual-frequency observation data can be used to calculate the STEC of the signal propagation path . As the tion (1) ,21.(1)TIn this study, the aforementioned method was used to calculate ionospheric GNSS STEC in the Antarctic. To ensure the accuracy of the calculation results, the cutoff of the satellite elevation angle was set as 15°. From Equation (1), it can be concluded that the accuracy of n are the orders of the polynomial. In this equation, the polynomial model is in order to i. According to the least square principle, using Equation (3) indicates that DCBs of receivers and satellites and polynomial coefficients is paper :(4)∑i=0mFor the IRI-2016 model, the vertical electron density of the top side (top of hmF2) and bottom side (bottom of hmF2) could be calculated using different formulations. The information of vertical electron density is described in STEC is the slant TEC of the ionosphere evaluated by the IRI-2016 model, l is the radio wave propagation path, and Based on the Consultative Committee on International Radio (CCIR) files, NeQuick2 uses specific parameters such as the electron density peak parameter of the F2 layer (NmF2), F2 peak height (hmF2), F2 layer spreading factor (M(3000)F2), and the solar activity index (F10.7) to calculate the electron density in the ionosphere at a certain time. Then, by integrating the electron density, the STEC can be evaluated by the NeQuick2 mode. Nava et al.  presenteThe Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) is a satellite mission for the Earth sciences to solve some of the most important geo-scientific issues today. Placing a constellation of GPS receivers in low-Earth orbit, COSMIC provides an extremely powerful system for continuously and extensively measuring the ionosphere . COSMIC,The accuracy of GNSS STEC depends on the accuracy of the DCBs of receivers and satellites. Thus, the DCBs estimated in this study were compared with DCBs provided by the Center for Orbit Determination in Europe (CODE). The precision of the estimated DCBs of 32 satellites and DCBs of five IGS stations were evaluated by analyzing the statistics bias and STD, as shown in As seen from STEC and GNSS STEC rather than VTEC to avoid errors introduced in the projection process. Based on the analysis presented above, the calculated GNSS STEC can be regarded as the true value of STEC. To investigate the accuracy of the IRI-2016 STEC and NeQuick2 STEC, in this study, the difference and its absolute value between the GNSS STEC and the modeling STEC (IRI-2016 STEC or NeQuick2 STEC) were computed, as shown in Equation (6).In contrast to previous research methods, we compared modeling In high-latitude areas, the ionosphere dynamic depends on not only the background solar radiation, but also on the electron and proton fluxes and, especially, on their variation geomagnetic storms. The disturbance storm time (Dst) index  is obtaiIn the Antarctic, the solar radiation intensity is different in different months and is also different at different latitudes within the same month. Since the ionospheric electron density and TEC are both greatly influenced by solar radiation, it is crucial to consider the influence of solar radiation when assessing the accuracy of the empirical model of the Antarctic area. In June, the Antarctic is in Polar Night and almost all regions are not affected by solar radiation. In December, it is Polar Day and almost all regions are directly exposed to solar radiation. In March and September, half of the Antarctic area is on the day side and the other half is night side. Solar radiation on the day side gradually decreases as latitude increases, while the night side is more affected by solar radiation in high-latitude areas. Since the radiation conditions in March and September are basically the same, the Antarctic is divided into day side and night side . Then, both the day side and the night side are divided into six latitude bands with intervals of 5° in latitude, as shown in IRI-2016, NeQuick2, and COSMIC in different layers. COSMIC data, whose geographic coordinates are within the Antarctic (60° S to 90° S) during corresponding periods, were chosen. In addition, COSMIC data with an incomplete or questionable electron density (Ne) profile were rejected. Rate of misestimation of models in each ionospheric layer were calculated, as shown below:In this paper, the experimental evaluation results were assessed by the statistics of TEC deviations provided by RME means the rate of misestimation, L represents different layers  of ionosphere, model means IRI-2016 or NeQuick2, and N is total number of occultation observations.The dSTEC values of the two models with GNSS STEC are shown in To analyze the deviation between the two models’ STEC and GNSS STEC, the difference in STEC was statistically distributed according to a statistical interval of every 1 TECu, as shown in As seen in In June and December, the bias values of the two models barely varied with the change in latitude, both in the polar day and polar night. The bias values of the IRI-2016 model during the polar day and polar night were approximately 2 TECu, while those of the NeQuick2 model were quite different. The bias value in each latitude band was approximately 10 TECu during the polar day, while it was approximately 3 TECu during the polar night. The RMS values of the two models were close to each other during the polar night, approximately 2–3 TECu, which were much lower than those during the polar day. The RMS of the NeQuick2 model on a polar day was greater than that of the IRI-2016 model, and the difference increased with latitude, which was nearly 0.1 TECu in lower latitude bands while approximately 1 TECu in higher latitude bands. Accordingly, it was concluded that the stabilities of the two models were both affected by solar radiation. The stabilities of the two models were better on the night side than on the day side, and the stability of the NeQuick2 model was weaker than that of the IRI-2016 model.The above results show that the performance of the IRI-2016 model was better than that of the NeQuick2 model in terms of the accuracy and stability of the estimation results, and the quality of the two models’ results were both affected by solar radiation. The IRI-2016 model was less affected by solar radiation than the NeQuick2 model. The estimation result of the NeQuick2 model was less stable than the IRI-2016 model on both the day and night sides.In this study, the GNSS STEC with high accuracy was regarded as the true STEC value by evaluating the accuracy of DCB. The IRI-2016 STEC and NeQuick2 STEC were estimated within the altitude height range of 60 km to 2000 km, respectively. Afterward, the Antarctic was divided into different latitude bands, and the solar radiation difference was also considered in this paper. Based on the above design, the accuracy and stability of the two models were compared by analyzing the difference between the two modeled STEC and the GNSS STEC (dSTEC), bias, and RMS value. The experimental conclusions were as follows: Both IRI-2016 and NeQuick2 underestimated STEC in the ionosphere in the Antarctic. This may be because the GNSS STEC contains both the ITEC and the PTEC, while the modeled STEC was only estimated up to a height of 2000 km. However, the content of PTEC in the Antarctic is very low and cannot be the only cause of this result. Compared to the two empirical models, the IRI-2016 STEC was closer to the true STEC. In June, the STEC difference between the two models was basically maintained within 2 TECu. In March and September, the NeQuick2 STEC was approximately 3–10 TECu lower than that of the IRI-2016 model. In December, the difference between the two models was more pronounced. Since the introduction of the AMTB and SDMF2 models to simulate hmF2 directly, the IRI-2016 STEC performed significantly better than the NeQuick2 STEC. Bias of both models did not vary greatly with latitude on the night side but decreased and then increased as latitude increased on the day side. This could be because the GNSS STEC in the Antarctic is generally small and gradually decreases as latitude increases, but the modeling accuracy near the pole was poor owing to the lack of observational data. In the intermediate latitude bands (70–80° S) of the Antarctic, the bias value between day and night side was close, with a difference of approximately 0–1.5 TECu. In the lower (60–70 degrees S) and higher latitudes (80–90° S), the bias value on the day side was larger than that on the night side, with a difference of approximately 1–3 TECu. In addition, the variation of the bias value of the NeQuick2 model between different latitudes was more obvious. In conclusion, the modeling accuracy near the pole must be improved, which can be considered in the next versions of the two models. The dSTEC values of the two models were both normally distributed. The distribution range of both the modeled dSTEC increased as solar radiation increased, and the NeQuick2 STEC was systematically biased as solar radiation increased. The RMS value of the IRI-2016 model was always smaller than that of the NeQuick2 model, and the RMS values of the two models increased with solar radiation intensity.All these results indicate that the estimated results of the two models were more stable under weak solar radiation. Since the IRI-2016 uses new hmF2 models to avoid the error source connected with the M(3000)F2 approach, IRI-2016 is less affected by changes in solar radiation and its performance is more stable.


The patterning is based on a self-organized pore arrangement directly fabricated from a ternary system of a solvent-nonsolvent biopolymer. We successfully created a porous honeycomb-like pattern (HCP) on a thermally resistant polymer—fluorinated ethylene propylene (FEP). An important preparation step for HCP is activation of the substrate in Ar plasma discharge. The polymer activation leads to changes in the surface chemistry, which corresponds to an increase in the substrate surface wettability. The aim of this study was to evaluate the influence of the PLLA concentration in solution on the surface morphology, roughness, wettability, and chemistry, and subsequently, also on fibroblast proliferation. We confirmed that the amount of PLLA in solution significantly affects the material surface properties. The pore size of the prepared layers, the surface wettability, and the surface oxygen content increased with an increasing amount of biopolymer in the coating solution. The optimal amount was 1 g of PLLA, which resulted in the highest number of cells after 6 days from seeding; however, all three biopolymer concentrations exhibited significantly better results compared to pristine FEP. The cytocompatibility tests showed that the HCP promoted the attachment of cell filopodia to the underlying substrate and, thus, significantly improved the cell–material interactions. We prepared a honeycomb biodegradable support for enhanced cell growth, so the surface properties of perfluoroethylenepropylene were significantly enhanced.In this study, we present the surface patterning of a biopolymer poly( The surface morphology and roughness of materials significantly influence cellular behavior in applications, including cell seeding . In geneOne of the possibilities is the formation of porous films with various pore shapes. A typical example of a porous surface inspired by nature is the formation of hexagonal units, which is called honeycomb-like patterning (HCP) . Nishikal-lactide) (PLLA). The positive effect of PLLA as a cell scaffold has been studied for a long period [In tissue engineering, synthetic polymers, whose advantage is their easy formability , and biog period ,13. An ig period . This prg period . Honeycog period ,16. The g period . Langmuig period .Our main focus of this study was to evaluate the cytocompatibility of a polymer foil when applying a PLLA HCP-like film prepared by improved phase separation. Human primary fibroblasts were chosen for this purpose, since they are widely used in various applications in clinical practice . We focu3; stabilized with 1% ethanol A.G., Mr 119.38) and methanol  obtained from Penta, Prague, CZ, were used. For HCP (coating) formation, poly-l-lactic acid  was used. A circular substrate with a diameter of 20 mm, known as fluorinated ethylene propylene , was activated by Ar plasma discharge [3/MeOH) for 10 s at room temperature  and subsequently, the porous pattern was formed by evaporating both solvents . NanoScope Analysis software was applied for data processing. The arithmetic roughness (Ra) and root mean square (RMS) represent the average of the deviations from the center plane of the sample.The surface morphology of the prepared PLLA structures and detailed morphology of grown fibroblasts were examined by the scanning electron microscope (SEM) using an LYRA3 device . The samples were covered with a platinum conductive layer of a 20 nm thickness by a diode sputtering method (Quorum Q300T). The surface morphology and roughness were studied by the atomic force microscope (AFM) using a Dimension ICON device  using an F-MaxN analyzer and SDD detector . The samples were covered with a platinum conductive layer of a 20 nm thickness by a diode sputtering method (Quorum Q300T).The wettability of the prepared PLLA structures was studied by measuring the water contact angle. The contact angle was determined by the Surface Energy Evaluation System  by applying drops of distilled water to eight different positions.g, 1 min), the liquid was removed, and the cell pellet was gently resuspended with fresh prewarmed (37 °C) media. Nest, the cells were transferred to a dish with 10 mL of media. The cells were cultured according to the instructions of the manufacturer in Minimal Essential Media (MEM) supplemented with 2 mM L-Glutamine  and 10% fetal bovine serum . The cells were maintained at the exponential phase of growth at 37 °C, 5% CO2, and 95% humidity. The cells were passaged at a subcultivation ratio of 1:4 twice a week using 0.25% (w/v) trypsin-0.53 mM EDTA solution, and were allowed to detach for ca. 5 min. at 37 °C. Then, they were gently removed by fresh complete growth media and transferred to a new dish. The experiments were performed within 16 cell divisions, so that we were sure that the cells maintained their primary phenotype, even though the manufacturer claims that the cells are capable of 42–46 population doublings before the onset of senescence. No morphological changes were observed during the experiments.Human primary lung fibroblasts (MRC-5) were purchased from the American Tissue Culture Collection  as a frozen vial, which was unfrozen in a water bath of 37 °C. Then, it was gently centrifuged  soluted in complete phenol red-free MEM medium ; the cells were incubated for 2 h. After that, the culture medium was transferred to sterile 96-well plates  and the absorbance of the arisen formazan was spectrophotometrically recorded at 450 nm (the reference wavelength of 650 nm). As controls, MRC-5 cells seeded on standard tissue culture polystyrene wells (PS) of 12-well dishes and on pristine FEP were used.The viability of MRC-5 cells was measured using an assay that measures the cellular viability, known as the WST-1 test , as in ref. , which cIn order to examine the detailed morphology of MRC-5 cells attached and growing on the tested samples, SEM  analysis in a secondary-electron mode was performed. For this purpose, the cells were seeded as described in chapter 2.4. Then, they were washed with prewarmed (37 °C) PBS and fixed with Karnovsky solution in 0.1 M cacodylate buffer (pH 7.2) for 2 h, as described in . After tBased on the principle of improved phase separation, we were able to create a polymer HCP on a modified polymer foil. We discussed the beneficial effect of plasma modification on the FEP polymer, especially for improvement of the surface wettability, chemistry, roughness, and cytocompatibility enhancement, in our previous study . The conFirst of all, we were interested in the effect of the PLLA content in the coating solution under otherwise constant conditions (solvent volume ratio and plasma modification parameters). The surface morphology of the HCP prepared with different amounts of PLLA  is shown in We can conclude that the conditions during plasma pretreatment have a great influence on the resulting HCP. In this experiment, we worked with the parameters that showed the most promising results, according to our previous measurements (8 W and 240 s). Moreover, the shape of the pores was the most regular in a layer containing 2 g of PLLA B, with aFurthermore, we also measured the wettability of the presented porous layers, depending on the amount of PLLA in the polymer solution for one month . In the Usually, during the aging of the plasma-exposed polymer, the wettability of the surface decreases after a few days (the polarity of the surface decreases). This is due to the reorientation of oxygen functional groups formed during plasma pretreatment towards the volume of the material. In our case, we did not observe this effect, due to the character of the surface (biopolymer microstructures on plasma-exposed fluoropolymer). The fluctuating values of the contact angles of all samples during the whole month can probably be justified by the plasma modification of the substrate before the application of the layer. During the aging of the substrate, chemical changes occurred in the surface of the polymer, which led to a change in the wettability . Over thAs well as the wettability, surface chemical changes depending on plasma treatment were studied in the previous study . This tia and RMS) on the amount of PLLA supplemented with the corresponding images of the surface morphology obtained from AFM is introduced in 2; PLLA 1 g, the Sa was 102 μm2; PLLA 2 g, the Sa was 239 μm2; and PLLA 3 g, the Sa was 110 μm2. Bui reported three main points regarding an appropriate choice of methanol as a nonsolvent to induce phase separation in normal air and to support the formation of an ordered structure. Firstly, its high affinity with water. Therefore, the enrichment of methanol in the solution through solvent evaporation is favorable for absorbing water vapor from the ambient environment. Secondly, the high solubility with water-immiscible solvents, such as chloroform, was reported, and last but not least, methanol accumulation was reported to induce the transport of polymers to the surface of nonsolvent droplets [A graph of the dependence of roughness (Rdroplets  under a The second step of our work was to monitor the behavior of human primary fibroblasts (MRC-5) on the porous pattern. All prepared samples were evaluated for MRC-5 viability using the WST-1 assay 1, 3, and 6 days after seeding . As contIn this study, we covered the FEP substrate with a biopolymer porous pattern for cytocompatibility improvement. The application of the PLLA layer had a positive effect on the surface properties of the substrate, and the number of cells was significantly increased on the biopolymer microstructure compared to pristine FEP. We wanted to determine the cell response on the biopolymer micro pattern with the advantage of further biopolymer support and biodegradability, and we succeeded. The wettability and roughness of the substrate increased rapidly. The cytocompatibility tests showed very positive results after the cultivation of human primary fibroblasts on the coated FEP. The effect of the amount of PLLA proved to be a very important factor for the formation of the layer with different properties considering the morphology and wettability, and the presence of PLLA microstructures proved to be a very important factor for the growth of the MRC-5 cells. The polymer solution with a higher amount of PLLA led to a layer with the largest pores and the highest surface wettability corresponding to the highest oxygen content. The highest cell number was detected on the PLLA layer prepared from 1 g of PLLA in solution (except for tissue polystyrene). From this study, we can say that the HCP pattern from PLLA can be described as comparable and non-toxic compared to tissue polystyrene. The PLLA pattern present on the treated FEP foil can be used for the enhancement of MRC-5 cell growth. For all three concentrations of PLLA, the results for the support of cell growth were significantly better when compared to pristine FEP. The higher amount of PLLA (3 g) led to a slightly more inhomogeneous distribution of cells, which is represented by the higher error of measurement. On the contrary, for a lower PLLA concentration (1 g), the number of cells was even comparable to tissue polystyrene and the cell distribution was more homogeneous compared to 3 g of PLLA. These findings could provide a new valuable direction for further research and development in the field of tissue engineering and cytocompatibility enhancement.


This study investigated the solubilization capabilities of rhamnolipids biosurfactant and synthetic surfactant mixtures for the application of a mixed surfactant in surfactant-enhanced remediation. The mass ratios between Triton X-100 and rhamnolipids were set at 1:0, 9:1, 3:1, 1:1, 1:3, and 0:1. The ideal critical micelle concentration values of the Triton X-100/rhamnolipids mixture system were higher than that of the theoretical predicted value suggesting the existence of interactions between the two surfactants. Solubilization capabilities were quantified in term of weight solubilization ratio and micellar-water partition coefficient. The highest value of the weight solubilization ratio was detected in the treatment where only Triton X-100 was used. This ratio decreased with the increase in the mass of rhamnolipids in the mixed surfactant systems. The parameters of the interaction between surfactants and the micellar mole fraction in the mixed system have been determined. The factors that influence phenanthrene solubilization, such as pH, ionic strength, and acetic acid concentration have been discussed in the paper. The aqueous solubility of phenanthrene increased linearly with the total surfactant concentration in all treatments. The mixed rhamnolipids and synthetic surfactants showed synergistic behavior and enhanced the solubilization capabilities of the mixture, which would extend the rhamnolipids application. Hydrophobic organic compounds are commonly found in soil and groundwater in industrialized areas. Among many hydrophobic organic compounds, polycyclic aromatic hydrocarbons have caused widespread concern on account of their poisonousness to humans and to ecosystems. Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds composed of two or more aromatic rings fused with carbon and hydrogen atoms . Due to Based on this different principle, various remediation methods for PAH-contaminated sites have been proposed ,5,6. SurPseudomonas aeruginosa. Rhamnolipids (Rham) are surface-active glycolipids of microbial origin [In this paper, the interfacial behavior and solubilization capabilities of a mixture of biosurfactants with a synthetic surfactant was studied. Biosurfactant is mainly produced by microorganisms and have various structures . The mosl origin . The nonl origin . As a tyThe goal of this study is to reduce the use of synthetic surfactant. The solubilization capabilities of rhamnolipids and synthetic surfactant mixtures for the application of surfactant-enhanced remediation was investigated. Further, the mechanism of possible synergism was analyzed based on the CMC values and solubility data obtained of the single and mixed surfactants. In addition, the influential factors, including pH, ionic strength, and acetic acid concentration were studied.The biosurfactant rhamnolipids was purchased from Hunan Zhijin Biotech Co., Ltd., Changsha, China. The biosurfactant was originally received as a blend of 2/3 mono-rhamnolipid and 1/3 di-rhamnolipid, and no further alteration was performed. It is a brown viscous liquid with approximate purify of 40%. The nonionic surfactant TX100 was with purity higher than 98%, and phenanthrene was with purity greater than 97%, both substances were obtained from Tokyo Chemical Industry Co., Ltd., Tokyo, Japan. Acetic acid was purchased from J&K Scientific Ltd., Beijing, China. The selected properties of above substances are shown in The CMC values of the individual and blended Triton X-100 and rhamnolipids solution were determined by the DuNuoy ring method . A serieA stock solution was prepared by dissolving individual Triton X-100 or rhamnolipids in water. The stock solution was diluted to 3000, 2500, 2000, 1500, 1000, 500, and CMC mg/L, respectively. The mass ratios of TX100 and Rham were enacted at 1:0, 9:1, 3:1, 1:1, 1:3, and 0:1.The solubility of phenanthrene was measured in individual or mixed surfactant solutions. For each batch test, excess amount  phenanthrene was added to glass flasks containing a series of 50 mL individual or mixed surfactant solutions to ensure maximum solubility.These samples were set for the HZQ-F160 model reciprocating shaker  at approximately 200 rpm at 20 °C for 24 h. After shaking, the beakers were centrifuged with LD-5 model centrifuge  at 1666 g for 20 min. After solubilization experiments, the samples were taken with 10 mL glass syringes and filtered through a 0.2 μm poly-tetrafluoroethylene filter. Filtered samples were then analyzed with high-performance liquid chromatography . The specific experimental conditions have been described in our earlier study . All theCMC12,theor) can be predicted as proposed by Clint [1 is the bulk mole fraction of TX100 in the binary surfactants, CMC1 is the critical micelle concentration of TX100, CMC2 is the critical micelle concentration of rhamnolipids, and CMCtheor is the critical micelle concentration of ideal mixed surface agent.Based on a simple phase separation model with the assumption of ideal mixing of surfactants in the micelles, the CMC of the mixture , which be calculated by the following :(4)WSR=SWSRtheor can be calculated by the following:WSRtheor is the WSR value for phenanthrene in mixed TX100/Rham mixture system at the ideal binary state. WSR1 and WSR2 are the weight solubilization for TX100 and Rham. m1 and m2 are the mass fraction of TX100 and Rham in the mixed surfactant system, respectively.To illustrate the synergetic solubilization ability of surfactant mixture, mK is defined as the distribution of organic compounds between the micelle and the aqueous phase, which can be calculated by the following formula [mK represents the partition of the organic compound between micelles and the aqueous phase, wV represents the molar volume of water.The partition coefficient  formula :(6)Km=SamK12 is defined as partition of the neutral nonpolar organic solute between micelle and aqueous phase in a mixed surfactants system, which can be calculated by the following [mK12 is the micelle–water partition of the solute in mixed surfactants systems, mK1 is the micelle–water partition of the solute in TX100, mK2 is the micelle–water partition of the solute in rhamnolipids, and B represents the empirical parameter including inter-surfactant and surfactant-solute interaction.To obtain the partition of phenanthrene between micelle and surfactant mixture, the partition coefficient ollowing :(7)lnKm1Gs (J/mol) during the process of phenanthrene molecules incorporation into micelles can be represented by the following expression [R, T and mK are the universal gas constant, the absolute temperature, and the micelle-water partition coefficient respectively; ΔsG represents the standard free energy change.The standard free energy change Δpression :ΔGs = −RCMCtheor can be calculated by Equation (1) and is listed in the CMCexp of the mixed surfactants increased with the decrease in the mass fraction of rhamnolipids and were smaller than the CMCtheor due to the synergistic effect. This negative deviation indicates the existence of interactions between two surfactants in the mixed aggregates. The addition of small amounts of TX100 led to a reduction in the electrostatic self-repulsion between the rhamnolipids head groups [The aqueous surface tension as a function of surfactant concentration for the individual and mixed surfactants is shown in d groups .XTX100 = 0.75 due to the electrostatic forces between the headgroups. X2 (the mole fraction of rhamnolipids in the mixed surfactants system) was generally higher than α2, which may be due to the easier formation of micelles by rhamnolipids as evident from its lower CMC value [To show the interaction between Rham and TX100, the interaction parameter β was calculated by Equations (2) and (3)  and is listed in Km is greater than Log Kow (Kow is the partition coefficient for octanol/water), which shows that the apparent solubility of phenanthrene is higher in the micelles than its solubility in the octanol.The solubility of phenanthrene in the presence of a single or mixed surfactant is shown in WSR are also listed in WSRexp are bigger than values of WSRtheor for the same TX100/Rham mixture ratio, which indicates the surfactant mixture have synergetic solubilization ability. The experimental values of apparent solubility are bigger than that of the theoretical values, indicating TX100 and rhamnolipids mixture has synergistic effect. This means that that when rhamnolipids are present, the solubility power of TX100 in the mixture is enhanced due to a synergic effect. In contrast to the ideal mixed effect, there is a deviation between the experimental value and the theoretical value and the solubility data were presented as “nonideality results”. A non-toxic surfactant of rhamnolipids, to partially replace the use of toxic surfactant of TX100, has practical meaning for environmental remediation.The experimental and theory values of Mixed surfactant systems with more negative β values often have the potential to reduce the solubilization of organics in the micellar phase. Packed micelle and micelle with negative β values can resist the entrance of the phenanthrene molecule from the aqueous phase into the micellar phase . Thus, sK12) and B in the mixed surfactant solution were investigated. B values were calculated by Equation (7) and listed in the Km value. All Km values were greater than 1 and the ΔGs value must come out to be negative, which shows the spontaneity of the solubilization process.Based on thermodynamic ground, the partition coefficient of a neutral organic solute between micellar and aqueous phases  added to the surfactant solution could lower the CMC value, following the Corrin-Harkins equation [There are two possible explanations for this phenomenon. First, with the small addition of Nafactants . The numequation ,50. The equation . Adding Organic acids, such as oxalic, succinic, tartaric, and acetic acid occur widely in the soil environment, and they have a considerable effect on the solubilization capabilities of surfactants. Hence, the capabilities of mixed TX100/Rham system for phenanthrene using 5, 10, and 15 mg/L of acetic acid and a mass ratio between TX100 and rhamnolipids set at 3:1 was examined. The CMC values of the mixed surfactants solutions were 105, 85, and 72 mg/L at 5, 10, and 15 mg/L of acetic acid used, respectively. The CMC values of the mixed surfactant solutions were reduced with the increase in acetic acid concentrations, which could enhance the apparent solubilities of phenanthrene. The effect of solution acetic acid on phenanthrene solubilization is illustrated in Some possible explanations for this phenomenon are the following. First, acetic acid tended to diffuse and dissociate into the water, resulting in a decrease in the pH of the solution. Acetic acid was more susceptible to dissociation due to its higher polarity, which lowered the CMC values of the mixed surfactant and subsequently increased the solubilization capabilities. Second, acetic acid could be distributed into the surfactant tails, which would influence the mixed surfactant micelles structure. This high amount of organic acid close to the interfacial film makes it softer and more flexible, promoting the formation of a more complex structure and helping to solubilize the hydrophobic organic compounds . TherefoThe phenanthrene solubilization in a TX100/Rham mixture system was evaluated. Surface tension and micellar properties were evaluated by theoretical models. Mixed surfactant solutions show nonideality results as indicated by CMC and β values. The obtained β values and B values indicate that the solubilizing power of all mixed surfactant systems is improved. Solubilization capabilities increased with decreasing mass ratio of rhamnolipids in mixed micelles. The solubilization capabilities of the TX100/Rham mixture system for phenanthrene declined with the increase in the pH values of the solution from 5 to 9, but rose with the elevation of ionic strength and acetic acid concentrations. The mixtures of rhamnolipids and synthetic surfactants show a synergistic behavior and enhanced solubilization capabilities. Thus, the application of mixtures of rhamnolipids and synthetic surfactants will extend the use of these environmentally friendly biosurfactants and enhance their accessibility and cost-effectiveness, which will broaden the prospects for their application in the remediation of organically contaminated soil.


Existence of the eigenvalues of the discrete-time quantum walks is deeply related to localization of the walks. We revealed, for the first time, the distributions of the eigenvalues given by the splitted generating function method (the SGF method) of the space-inhomogeneous quantum walks in one dimension we had treated in our previous studies. Especially, we clarified the characteristic parameter dependence for the distributions of the eigenvalues with the aid of numerical simulation. The discrete-time quantum walks (DTQWs), as quantum counterparts of the classical random walks that play important roles in various fields, have attracted much attention in the past two decades ,4,5,6,7.Localization of the DTQWs is closely related to the existence of the eigenvalues of the unitary transition operators. However, there were few results for the study of localization from the viewpoint of the eigenvalues of the unitary operators, though there were many approaches for localization ,11,12,13In this paper, we focus on the space-inhomogeneous QWs in one dimension. As simple cases, we treat the QWs induced by the Hadamard walk we had studied in our previous studies ,17,18,19The rest of this paper is organized as follows. The definitions of our DTQWs and the main results are given in In this paper, we consider the DTQWs on t is represented byt. Here, L and R correspond to the left and right chirarities, respectively, and T stands for the transposed operator. Let us prepare a sequences of The DTQWs are defined as unitary processes in which each coin state at each position varies with given unitary operations. The quantum walker in this paper is also manipulated by unitary operations. The system of the DTQW at time S is the standard shift operator defined byPutIn our study, we consider the eigenvalue problemloped in  is one oloped in , for insThe time evolution is determined byectively .Hereafter, as simple cases of the space-inhomogeneous QWs in one dimension, we focus on the QWs originated from the Hadamard walk we had treated in our previous studies ,17,18,19H is the Hadamard gate defined byAt first, we focus on the Wojcik model, whose unitary transition operators are (1){Ax}xThe Hadamard walk can be given by Equation . We notek et al.  solved tk et al.  and Endok et al.  derived Now let o et al.  solved tHere, we give the illustrations of the movements of the eigenvalues given by the SGF method  of the W(1)(2)LettingNote that the eigenvalues can be obtained by Equations (3.8) and (3.9) of Proposition 1 in :(1)β=iαNow let Next, our one-defect model is defined by the set of unitary matrices (2){Ax}xPut given in .Now we show the illustrations of the movements of the eigenvalues given by the SGF method of the Hadamard walk with one defect  and the Note that the eigenvalues can be obtained by Proposition 3.1 in :(1)(2)PuttingPut We emphasize that the eigenvalues emerge only on Here we consider the QW whose time-evolution is determined by the unitary transition operators (3){Ax}xn detail . We shouNow the solutions of the eigenvalue problemribed in . Here, wWe remark that the illustration is a diagram of the numerical simulation to investigate the parameter dependence continuously by using mathematica. Note that the eigenvalues can be obtained by Proposition 1 in :LettingBy putting We see that the two-phase quantum walk with one defect does not have the eigenvalues on meter ϕ.  We also Lastly, we introduce the QW which does not have defects, whose unitary matrices are (4){Ax}xe defect ,16. Hereudied in ,11,22.Let us consider the eigenvalue problemgiven in . Now we Note that the eigenvalues can be obtained by Theorem 1 in :PuttingLet We emphasize that the eigenvalues emerge only on As simple cases, we focused on four kinds of the space-inhomogeneous QW models in one dimension originated from the Hadamard walk. According to the previous studies ,17,18,19on occur ,24,25,26on occur  who clai


Aging can lead to functional and cognitive alterations, sometimes limiting older adults in their social development, especially illiterate groups of older adults who receive poor attention from healthcare systems. In this context, the present investigation proposes the cognitive training program “MENTE SANA [HEALTHY MIND]” to improve the cognitive functions of illiterate older adults in Arequipa (Peru). It is a type of quasi-experimental research with a pre-test/post-test design with a homogenous control group. The sample was made up of adults 60 years old and above and of female gender. The Montreal Cognitive Assessment (MoCA) test was used to detect the level of cognitive decline in illiterate older adults. The 50-sessions program was applied to all the older adults with mild cognitive impairment that were selected for the study, on a daily basis. It was found that the tested group improved their cognitive functions compared to the control group. These results help to propose adapted cognitive training programs for illiterate people. It is estimated that the cases of dementia will increase in developing countries such as Peru, from 7.4% to 12% in 2025, and although these data could vary ” is effective for the rehabilitation or the delay of cognitive deterioration in illiterate older adults.The specific objectives were: (1) Identify the level of cognitive decline in illiterate older adults (2) Apply a cognitive training program in illiterate older adults with mild cognitive impairment (3) Measure the level of cognitive decline in illiterate older adults with mild cognitive impairment after the application of the cognitive training program (4) Compare the results obtained between the control group and treatment group.The participants of the study belong to a Peruvian Social Security Health Institution known as EsSalud, which is committed to the integral health of those insured. The III Elderly Center La Victoria and the II Elderly Center Miguel Grau were selected as generational meeting spaces aimed at improving the quality of life of older adults through the development of family integration, inter-generational, socio-cultural, recreational and productive programs with lifestyles for active aging. The people who attended these centers are retired older adult residents at home who regularly attend workshops including dance, aerobics, therapeutic gymnastics, TAI-CHI, computing, crafts, pastry, among others.The sample consisted of 30 illiterate older adult women from 65 to 75 years of age originating from urban areas of medium socioeconomic status and selected non-probabilistically for convenience. The inclusion criteria considered were: (1) daily attendance so that they can persevere in the application of the cognitive training program, (2) agreement to participate voluntarily and comply with informed consent, (3) an initial score of mild cognitive impairment (17 to 21 points) in the Montreal Cognitive Assessment test, and (4) absence of psychiatric history, sensory disturbances, or chronic diseases.In order to measure the level of cognitive impairment, the Montreal Cognitive Assessment (MoCA)  was usedIts use was based on its simplicity and speed of application, in addition to its recognized reliability, dependability, validity, and adaptation in Latin America. The results of a study indicate that the MoCA test has a high inter-rater reliability of 0.91; good internal consistency (Cronbach’s Alpha = 0.85) and is able to discriminate different levels of cognitive impairment by showing adequate sensitivity (0.84) and specificity (0.71). This allows it to be postulated as useful and appropriate for screening cognitive changes in the Latin American population. Likewise, this analysis confirms that different values were found for the cut-off point of sensitivity and specificity according to the degree of education, so in subjects with primary or lower education, the score of 21/22 is considered as the cut-off point between normality and mild cognitive impairment ,18.It consists of 19 items and 8 cognitive domains with a maximum total score of 30 points that rates activities such as: visuospatial/executive (5 points), identification (3 points), memory (no points), attention (6 points), language (3 points), abstraction (2 points), delayed recall (5 points) and orientation (6 points).In order to carry out the application of the cognitive training program, a manual for illiterate older adults was used, designed by the authors of this article and validated by the judgment of three expert clinical psychologists with experience in older adults who passed the MENTE SANA cognitive training program through an evaluation matrix in which various criteria were rated. These include the precision of the instructions, the size, and sharpness of the images, the distribution of space, the dynamics of the sessions, the preventive purpose of the manual, the relevance and necessity of the sessions, the intervention at the different levels of the individual , the specificity in the design of the manual for illiterate older adults, the duration of each session, the progressive difficulty of the sessions, the similarity of the exercises with the cultural reality of the participants and their suitability for them to comply with training cognitive skills .The MENTE SANA cognitive training manual has 50 sessions with a duration of approximately 25 min each, in which numerous exercises were performed, such as process sequence, copying and drawing images, identifying objects of everyday life, retaining information in the short term, copying graphic patterns, expressing feelings and emotions through words, searching for patterns, interpreting sentences, long-term retention of information, determining the position and movements of the body in space and time, solving mazes, narrating and creating stories, telling anecdotes, identifying differences and similarities, teaching antonyms and synonyms, identifying places, learning holiday dates, identifying people, professions, animals, naming and describing objects and doing manual work. The sessions were led by two experts who instructed the participants in the development of each session of the manual. The implementation of the cognitive training program lasted 2 and a half months and was carried out in small groups of approximately 3 to 5 people.This was implemented based on accessing the institution’s database to identify the illiterate older adults. The distribution of the groups took into account that participants residing in different centers for the elderly could not exchange information about the exercises trained during the sessions. Thus it was determined that the control group was made up of those insured by the II Miguel Grau Senior Center and the treatment group by those insured by the III La Victoria Senior Center where the independent variable (the “MENTE SANA” cognitive training program) was manipulated in order to check its effect on the dependent variable (mild cognitive impairment), taking place in a natural context .Firstly, after obtaining the research approval by the EsSalud Ethics Committee and the Research Committee of the Universidad Nacional de San Agustín de Arequipa and EsSalud, the signatures of the informed consents were collected and the participants were divided in two groups: 15 older adults from III La Victoria Senior Center were assigned to the treatment group (GT) that received “MENTE SANA cognitive training”, and 15 others to the control group (GC) belonging to the II Miguel Grau Senior Center. Both groups were submitted to the pretest evaluation in order to determine the level of cognitive impairment. Subsequently, after the application of 50 daily sessions of approximately 25 min each during a two-and-a-half-month period, a second evaluation was implemented to the total sample to check whether cognitive training had any rehabilitative effect on the treatment group participants compared to the control group.A quasi-experimental design of two intact non-randomized equivalent groups was implemented (control group and treatment group) because the participants were assigned to each group according to the center for the elderly they attended. The data were analyzed using the Statistical Package for Social Sciences , version 23. Based on the analysis of normality of the sample  and its corresponding normal distribution, a general linear model of repeated measures was obtained (pre and post) and compared between groups (treatment and control).t-test was applied between pre- and post-tests for each of the cognitive domains evaluated by the MoCA.The following analyzes were carried out in detail: (1) Classification of the level of cognitive decline in illiterate older adults of the III La Victoria Senior Center and II Miguel Grau Senior Center. EsSALUD. (2) Classification of the cognitive deterioration level in illiterate older adults of the III La Victoria Senior Center and II Miguel Grau-ESSALUD Senior Center after applying the cognitive training program. (3) A general linear model of repeated measures (pre and post) was obtained and a comparison between groups (treatment and control) was performed. (4) Student’s t-test, these were not considered significant with a value p = 0.271. Therefore, the initial stage of the experimental study started with common results in which both groups did not have significant differences in relation to the MOCA evaluation and most of them presented mild cognitive impairment.Of the distribution percentage of the normality criteria that were obtained when applying the MoCA method to illiterate older adults with mild cognitive impairment in the III La Victoria-Essalud Senior Center, in the pretest stage, 100% (15) of the control group was identified with mild cognitive impairment, and for the treatment group, 93.3% (14) was identified with mild cognitive impairment. Likewise, in the evaluation of mean values, it was observed that in the pre-test stage, the control group obtained a mean value of 18.60 points (and a standard deviation of 1.24 points) less than the treatment group with a mean value of 19.13 and a standard deviation of 1.35. These differences were identified in both control and treatment groups in the pre-test and, according to the statistical Student’s p = 0.0001) reflect significant changes in the two groups between the two evaluation times (pre and post); changes that are different for each group . These also appear as inter-group differences  with a very high effect size (ETA = 0.989) and a power of 1.000.Consequently, in t-tests between the domains evaluated by the MoCA (p = 0.001) identification , attention , language , and orientation , with the differences for the remaining scales being insignificant.This demonstrates that there is no significant improvement in cognitive functions in the control group participants, while in the treatment group there is evidence of significant improvement in the cognitive functions that existed in the participants after having implemented the cognitive training program, which led to an increase of 6.5 points on average in the test used. As can be seen, the impact sizes are moderate to considerable, and the power is very high for both intra-subject effects (change in the treatment group from pre- to post-tests) and for inter-subjects effects (differences between groups after treatment application). Student’s the MoCA  show sigThe MENTE SANA [HEALTHY MIND] program applied to illiterate elderly people with mild cognitive impairment achieved a very significant improvement in their cognitive performance, which in average values represents 6.5 points, reflecting in the treatment group that initially, according to the MOCA method, 100% 14) of the participants were identified with mild cognitive impairment and after training 46.7% (7) were identified with mild cognitive impairment, and 53.3% 8) identified as normal. That is, 53.3% of the old adults improved their initial cognitive status to normal. These subjects significantly increased their cognitive execution at a level equal to or greater than other MCI elderly people with an educational level  higher t identifi of the p