Main Phase Research Articles

Treatment Free Remission after Nilotinib Plus Peg-Interferon Alpha Induction and Peg-Interferon Alpha Maintenance Therapy for Newly Diagnosed Chronic Myeloid Leukemia Patients; The Tiger Trial

Background: The TIGER-trial (NCT01657604) is a multicenter, randomized phase III study to evaluate efficacy and tolerability of nilotinib (NIL) vs NIL+pegylated interferon alpha2b (IFN) combination therapy with IFN maintenance as first-line treatment for patients (pts) with chronic myeloid leukemia (CML) in chronic phase. Methods: A total of 717 pts were recruited from 110 sites in Germany, Switzerland, and the Czech Republic. A pilot phase (n=25) validated the feasibility of the combination of NIL 300 mg BID and IFN (30-50µg/week according to tolerability and commenced after ≥6 weeks NIL monotherapy). In the main phase, 692 pts were randomly assigned to NIL (n=353) and NIL/IFN (n=339). Achievement of major molecular remission (MMR, BCR::ABL1 ≤0.1% on the International Scale, IS) after >24 months (mo) of therapy was the trigger to start the maintenance phase; treatment-free remission (TFR) started in pts with ≥12 mo persistence of MR 4 ( BCR::ABL1 ≤0.01% IS) after >36 mo total therapy. Quality of life (QoL) was evaluated using EORTC QLQ-C30 and CML24 questionnaires. Results: From 692 randomized pts, 411 were male (59%), median age was 51 years (range, 18-85). In the monotherapy arm, median treatment duration with NIL was 3.1 years (0.02-8.9), median daily dose 600 mg (183-764). In the combination arm, median treatment duration with NIL was 2.3 years (0.02-9.1), median daily dose 600 mg (106-792). Median duration of IFN therapy was 2.4 years (0-9.0). A median of 77 (0-485) IFN injections were administered, the median dose of IFN per injection was 30µg (0-50). Probabilities of MMR and MR 4.5 ( BCR::ABL1 ≤0.0032% IS, Fig 1) by 24 mo were 89% (95% CI: 85-92%) and 49% (44-55%) vs 93% (89-95%) and 64% (59-69%) with NIL vs NIL/IFN, respectively. In 356 pts (53%) qualifying for the discontinuation phase (NIL, n=197; NIL/IFN, n=159), probabilities of maintained MMR by 24 mo were 53% (45-60%) and 62% (54-70%) after NIL and NIL/IFN, respectively, in an intention-to-treat-analysis (p=0.13). 273 (40%) eligible pts actually discontinued therapy (per-protocol-analysis, NIL, n=163; NIL/IFN, n=110). Probabilities of TFR by 24 mo were 53% (45-61%) vs 59% (49-68%) for NIL and NIL/IFN, respectively (Fig 2). Fifteen pts (2.2%) with atypical BCR::ABL1 transcripts (e1a2, n=7; e19a2, n=4; e8a2, n=2; e13a3 and e14a3, n=1 each) were randomized to receive NIL (n=7) or NIL/IFN (n=8). After a median treatment period of 37 mo (36-39) 9 pts achieved and maintained a BCR::ABL1 reduction of at least 4 orders of magnitude and were eligible for TFR. 6 pts failed to achieve an individual transcript decline by at least 3 logs. TFR was commenced in 7 and maintained in 6 pts after 32 (range, 20-84) mo. Adverse events of special interest grades 3-5 were arterio-vascular disorders in 9 vs 8%, fatigue in 2 vs 4%, thrombocytopenia in 8 vs 8%, and alanine aminotransferase elevation in 4 vs 9% of pts in the NIL vs NIL/IFN arms, respectively. QoL analyses revealed the perception of a decreased cognitive function and higher rates of fatigue in pts in the NIL/IFN arm, particularly in pts older than 40 years. In total, 24 pts (NIL, n=13; NIL/IFN, n=11) progressed to advanced disease. By 8 years, progression-free survival was 94% (95% CI: 90-96%) and 92% (88-95%), overall survival 95% (92-97%) and 94% (91-97%) in the NIL and NIL/IFN arms, respectively. 28 pts (3.9%) received an allogeneic stem cell transplantation, 14 after disease progression. 35 pts died (NIL, n=18; NIL/IFN, n=17), 9 related to CML. Conclusions: Survival of CML pts has reached probabilities close to normal. The combination of NIL with IFN is associated with a higher rate of molecular responses but also impaired tolerability. IFN maintenance is feasible, and resulted in a trend towards higher rates of long-term TFR. The study was conducted on behalf of the German CML Study Group in cooperation with the East German Study Group on Hematology and Oncology (OSHO) and the Swiss Group for Clinical Cancer Research (SAKK).

Enhanced independent component analysis and fuzzy C-mean clustering based on novel bat algorithm for noisy image segmentation

Fuzzy c-means clustering is widely recognized as one of the most effective methods for image segmentation and achieving accurate classification. However, this method has two significant drawbacks: its sensitivity to noise and its convergence to local minimum clusters’ centroids. In this paper, we proposed a novel model called EIFCMNB, which incorporates enhanced independent component analysis (EICA), fuzzy c-means clustering (FCMC) and novel bat algorithm (NBA) for noise image segmentation. The suggested model consists of two main phases: image denoising and extraction of the regions of interest (ROIs). In the first phase, the enhanced independent component analysis (EICA) algorithm is used for recovering a good quality image, from a noisy image of poor quality. Several noisy images, with noise variances ranging from 5 to 20, were filtered. The resulting images were then evaluated based on several criteria viz: Peak Signal to Noise Ratio (PSNR), Relative Norm Error (RE), Normalized Cross-Correlation (NCC), and Structural Similarity index measure (SSIM). In the second phase, the fuzzy c-means clustering based on a novel bat algorithm is adopted to calculate optimal clusters’ centroids and extract the ROIs. By incorporating the new bat algorithm, we aim to overcome the problem of converging to local minimums and achieve improved segmentation accuracy. Promising experimental results have been obtained by applying the proposed model to MRI brain images and x-ray welding images. Two criteria viz: VPE end VPC have been employed to evaluate the suggested approach. The experiments clearly demonstrate that our suggested model effectively addresses the sensitivity to noise problem and provides optimal clusters’ centroids. Moreover, it outperforms several FCMC-based algorithms, exhibiting superior performance in terms of image segmentation and classification.

Large Scale Traveling Ionospheric Disturbances During Geomagnetic Storms of 17 March and 23 June 2015 in the Australian Region

AbstractLarge scale traveling ionospheric disturbances (LSTIDs) can be detected using the critical frequency of F2 layer (foF2) of the ionosphere. The HF interferometry (HF‐int) technique is applied to the ionosonde data from low and mid latitude stations over Australia. For the first time, we present a comparison of TIDs detected during the geomagnetic storms of 17 March and 23 June 2015. The TID response for these two comparable superstorms is significantly different owing to the differing storm evolution patterns. The storm associated TIDs are more intense and longer compared to the solar terminator. Results demonstrate that the morphology of parameters continually varies over time due to highly dynamic ionospheric response to geomagnetic storms. For the March storms, TIDs velocities were 400–700 m/s at the onset phase, ∼500 m/s during the main phase and ∼600 m/s during the recovery phase. Their propagation directions were equatorward with east/west deviations. Lower period (∼60 min) TIDs were determined during storm onset whereas higher periods (∼140 min) were detected during the recovery phase. The June storm produced a different response. The TID velocity at the onset phase was ∼500 m/s but during the main and recovery phases the velocities were greater than 1,000 m/s. There were large deviations in velocity vectors at the different stations suggesting multiple sources of TID generation and possible resonating effects at middle and low latitude stations. Our findings indicate that while TID detection and storm phases co‐occur, the propagation characteristics of TIDs change dramatically throughout the storm.

Microstructure and mechanical properties of cast Mg-6Gd–Zr alloy with different Y addition

Microstructures and mechanical properties of Mg-6Gd-xY-0.5Zr (wt.%, x = 0, 0.5, 1 and 3) alloys with different conditions (solution-treated and 200 °C peak-aged) are investigated. Species of precipitates in Mg-6Gd-0.5Zr alloys are modified by Y addition. In 0Y, 0.5Y and 1Y alloys, β′ precipitates and tentacle-like structures with specific crystallographic directions around β′ body are the main phases. The crystallographic directions of tentacle-like structures are {112‾0}Mg. When 3Y is added, β′ and β1 precipitates become the main phases. Except that, the size and area number density of β′ precipitate are also influenced by adding Y. With Y addition, the size of β′ precipitate is refined, and its area number density increases. This phenomenon has been explained by theoretical method in this paper. According to the study, Mg-6Gd-1Y-0.5Zr alloy with good combination properties is developed. The yield strength, ultimate tensile strength and elongation of Mg-6Gd-1Y-0.5Zr alloy are 164.4 MPa, 280.6 MPa and 16.1 %, respectively. The strengthening precipitates in the peak-aged Mg-6Gd-Y-0.5Zr alloys are β′ precipitates, and the strengthening effect of the β′ precipitates on the yield strength of the Mg-Gd-(Y)–Zr alloys with low Gd/Y content is more obvious than the Mg-Gd-(Y)–Zr alloys with high Gd/Y content.

The Variation of Ionospheric O+ and H+ Outflow on Storm Timescales

AbstractGeomagnetic storms are primarily driven by stream interaction regions (SIRs) and coronal mass ejections (CMEs). Since SIR and CME storms have different solar wind and magnetic field characteristics, the magnetospheric response may vary accordingly. Using FAST/TEAMS data, we investigate the variation of ionospheric O+ and H+ outflow as a function of geomagnetic storm phase during SIR and CME magnetic storms. The effects of storm size and solar EUV flux, including solar cycle and seasonal effects, on storm time ionospheric outflow, are also investigated. The results show that for both CME and SIR storms, the O+ and H+ fluences peak during the main phase, and then declines in the recovery phase. However, for CME storms, there is also significant increase during the initial phase. Because the outflow starts during the initial phase in CME storms, there is time for the O+ to reach the plasma sheet before the start of the main phase. Since plasma is convected into the ring current from the plasma sheet during the main phase, this may explain why more O+ is observed in the ring current during CME storms than during SIR storms. We also find that outflow fluence is higher for intense storms than moderate storms and is higher during solar maximum than solar minimum.

An Investigation on the Ionospheric Response to the Volcanic Explosion at Hunga Ha'apai in 2021

AbstractThe Hunga Ha'apai volcano eruption (20.536°S, 175.382°W in Tonga), which started intermittently around December 2021 and most violently erupted on 15 January 2022, is considered to be the largest volcanic outbreak in recent decades. In this research, we derived the ionospheric total electron content (TEC) over Sanya (18.400°N, 109.600°E), Wuhan (30.530°N, 114.610°E), and Mohe (53.500°N, 122.370°E), from the Global Navigation Satellite System observations. Then we investigated the coupling between the volcano eruption and ionosphere through the TEC variations. The TEC anomaly decayed from about 10 days before main eruption of the Hunga Ha'apai volcano, and showed obvious fluctuations during the eruption phase. The TEC anomaly propagated periodically, with its autocorrelation‐analyzed period of about 16.5 hr during the intermittent outbreak and about 8 hr during the main outbreak phase. Its independently derived wavelet‐analyzed periods are about 9.4 hr during the intermittent outbreak and about 9.4 and 18.8 hr during the main outbreak phase. The propagation is mainly expressed in low frequencies, with energy concentrated in the range of 0–10−3 Hz. This study highlights that the preeruption activities may play an important role in the coupling between the volcanic eruption and ionosphere disturbances.

Magnetic Storm Effects on the Occurrence and Characteristics of Plasma Bubbles

AbstractThe Communications/Navigation Outages Forecast System satellite mission was designed to investigate the ionospheric conditions that lead to the formation of irregularities. Here, we have studied the effect of magnetic storms on the formation and evolution of plasma bubbles during the satellite's lifetime (2008–2015). During this period encompassing solar minimum and maximum conditions, many magnetic storms of varying intensity developed, producing a unique and rich data set of 248 storms (14 intense, 69 moderate, and 165 weak) that occurred during the same timeframe to examine the role of external magnetospheric drivers in the production and dynamics of equatorial plasma bubbles. We have used the Planar Langmuir Probe and Ion Velocity Meter instruments to elucidate the role of magnetic storm intensity on the bubble's depth, internal speed, width, occurrence, and lifetime. The pre‐reversal enhancement (PRE) tends to increase during the main phase and when BZ is southward. New bubbles occur during large excursions of the PRE value. The bubble lifetime extends and remains active during the main and part of the recovery phase. The plasma velocity within the bubbles increases and typically becomes over 100 m/s during significant PRE and BZ negative times. The depth of bubbles reaches values close to 100% during intense storms. In general, the intensity of the storms seems to control and augment the plasma bubbles' depth, width, and internal velocity.

Improved Thermosphere Mass Density Recovery During the 5 April 2010 Geomagnetic Storm by Assimilating NO Cooling Rates in a Coupled Thermosphere‐Ionosphere Model

AbstractThe recovery of thermosphere mass density following geomagnetic storms is a result of competing heating and cooling processes. Simulations often underestimate the speed of the recovery. In this study, for the first time, we report that assimilating the Thermosphere Ionosphere Mesosphere Energetics and Dynamics Sounding of the Atmosphere using Broadband Emission Radiometry nitric oxide (NO) cooling rate profiles into a coupled thermosphere‐ionosphere model via the ensemble Kalman filter improves the thermosphere mass density recovery following a geomagnetic storm. This is due to the impact of the assimilation on both the cooling processes and the thermosphere circulation. The dynamical changes due to the assimilation include stronger upwelling and equatorial transport. These lead to an effective increase in NO at all altitudes at mid‐high latitudes, resulting in the improved recovery. The improved representation of cooling processes in the storm's main phase also results in improved >24 hr forecasts of the density recovery.

ИСТОРИЯ ФОРМИРОВАНИЯ ЗАЛЕЖЕЙ УГЛЕВОДОРОДОВ В ПЛАСТАХ МАЛЫШЕВСКОЙ СВИТЫ НА ТЕРРИТОРИИ КАРСКО-ЯМАЛЬСКОГО РЕГИОНА

The paper describes the characteristics of source beds, considers the structure of fluid seals and formation stages of anticline structures within Kara-Yamal region, bounded from the south by the Messoyakha inclined ridge. Investigations were carried out on the basis of comprehensive generalization of published geological and geochemical materials. It is shown that all formations of the Lower and Middle Jurassic containing aquagene, terragene and mixed types of kerogen in various proportions, possessed oil and gas generating properties. The significant implementation of generation potential due to the high OM catagenetic transformation in rocks of the Middle and especially Lower Jurassic caused the formation of mainly condensate gas accumulations in reservoirs of the Malyshevka Formation. The stages of formation of clay fluid seal in the process of lithogenesis are considered, it was determined by the feature of subsequent transgressive-regressive sediment filling relative to the deep–sea basin in the Late Berriasian – Early Aptian. The history of the anticline structure formation in the roof of the Jurassic structural stage is analyzed separately. According to the results of this analysis, it was found that hydrocarbon accumulations matured within the structures whose main stages of development coincided with the Jurassic period and Early Cretaceous epoch. The beginning time of filling traps with hydrocarbons was defined on the basis of information comparison about the time of compaction of clay strata of the Late Bathonian – Kellovian to the state of fluid seal and time of implementation of the HC main generation phases by oil –and- gas generating rocks. It is concluded that the lithification asynchrony of the fluid seal clay deposits predetermined the time diversity of the HC accumulation generation in the Malyshevka Formation in geological past.

Asynchronous generator replacement scheme with internal capacitive reactive power compensation

The relevance of using compensated induction machines in the generator mode of autonomous power supply systems is determined by their ability to provide a stable and reliable power supply even in the absence of an external grid. The research aims to develop a procedure for determining the characteristics of an equivalent circuit of compensated induction generators that considers the mutual influence between the main and additional phase windings of the armature. The theory of an idealised induction machine with the representation of electromechanical energy conversion processes and basic physical parameters in the form of equations of electrical equilibrium and drive motion was used to obtain the calculated characteristics of the generator’s operating modes of this class. The generalised system of differential equations made it possible to calculate dynamic and static processes for symmetrical and asymmetrical modes at given machine parameters under different methods of excitation and voltage stabilisation under variable load. For the practical implementation of modelling the parameters of an induction generator, the equations of electrical equilibrium of the stator and rotor circuits for the symmetrical steady-state mode are used, which is a special case of the generalised mathematical model of the machine for both transient and steady-state processes with constant parameters of the substitution scheme. Consideration of the structural and functional features of compensated induction generators was made possible by using a mathematical model with the armature winding divided into two coaxial or spatially offset half-windings. In this case, the number of calculation equations doubles. The use of an autotransformer scheme for switching on the stator phase half-windings to capacitors required the introduction of an additional differential equation for the electrical equilibrium of the stator phases. This made it possible to substantiate the values of active and inductive resistances used in the replacement circuit of an induction generator with internal capacitive reactive power compensation. The mutual inductive coupling of the main and additional half-windings of the generator stator phase windings due to both the operating magnetic flux and the magnetic fluxes of dissipation was considered. The practical significance of the obtained results is to increase the efficiency and stability of the power supply, which helps to reduce losses and improve the operation of electric power systems

Effect of the addition of acetic acid on spinning sol and mullite fibers properties

The preparation of mullite fibers by sol-gel method is the preferred method in industrial production, where the stability, rheological properties and microstructure of spinning sols are essential for the preparation of continuous, low-defect fibers. In this study, aluminum carboxylate solutions (ACs) were prepared using aluminum powder, formic acid and acetic acid as raw materials, silica sol was added, and spinnable sol was obtained by concentration and aging. After dry spinning and calcination at 1200 °C, continuous mullite fibers with mullite as the main crystal phases were obtained. The effect of acetic acid addition on the stability of Al-Si mixed sol was studied, and the polymerization process of spinning sol was studied on its rheological properties and microstructure. The cross-section of mullite fibers obtained after calcination at 1200 °C was “dumbbell” type, and the cause of this cross-section was discussed, which laid a foundation for subsequent optimization research.

Identification of Penetration and Disturbance Dynamo Electric Fields and Their Effects on the Generation of Equatorial Plasma Bubbles

AbstractA very challenging task in ionospheric studies is to determine the separate contributions of penetration and disturbance dynamo processes in the generation of equatorial plasma drift during magnetic storms. In this study, we analyze the ion drift measured by the Communications/Navigation Outage Forecasting System satellite during the magnetic storm on 15–16 July 2012. A unique feature of this storm is the exceptionally long period of continuous southward interplanetary magnetic field (IMF) for 32 hr. The storm‐induced net change of the meridional/vertical ion drift, the difference drift between the storm time and the quiet time, is derived during the storm main phase and the first 20 hr of the recovery phase with southward IMF. The difference drift during the recovery phase cannot be explained by the disturbance dynamo effect alone. A new method is used to separate the drifts caused by the penetration and disturbance dynamo processes. The penetration drift is represented by an empirical pattern of penetration electric field and depends on the IMF magnitude, and the disturbance dynamo drift is obtained by subtracting the penetration drift from the measured difference drift. The derived disturbance dynamo drift is in good agreement with previous statistical pattern. This is the first effort to identify the separate contributions of the penetration and disturbance dynamo processes to the total drift from observed data. The results have important implications in identifying storm‐time penetration and disturbance dynamo electric fields and their effects on the generation and evolution of plasma bubbles.

Effect of Cobalt and Chromium Content on Microstructure and Properties of WC-Co-Cr Coatings Prepared by High-Velocity Oxy-Fuel Spraying.

To explore the Co/Cr ratio impact on the high-velocity oxygen fuel (HVOF)-sprayed WC-Co-Cr coatings microstructure and performances, three kinds of WC-Co-Cr coatings, namely WC-4Co-10Cr, WC-7Co-7Cr, and WC-10Co-4Cr, were prepared by using a high-velocity oxygen fuel (HVOF) spraying process. The three coatings' phase composition, microstructure, basic mechanical properties, abrasive wear, and corrosion resistance were investigated. The results show that all three WC-Co-Cr coatings comprise the main phase WC, minor W2C, and amorphous W-Co-Cr phase, besides the WC-4Co-10Cr coating containing a small amount of CrxCy phase. In addition, WC-7Co-7Cr coating exhibited the highest hardness and abrasive wear resistance, followed by WC-10Co-4Cr and WC-4Co-10Cr coatings. The corrosion resistance as a hierarchy was found to be WC-10Co-4Cr > WC-7Co-7Cr > WC-4Co-10Cr.

Research on microstructure and properties of 3D plasma spray welding repair layer of continuous casting segmented rollers

In this paper, the Fe-Cr-Ni-Si powder was used in a 3D plasma spray welding machine to perform spray welding repair tests on continuous casting segmented rollers for service life improvement. The phase composition, hardness distribution, abrasion resistance and thermal stability of the spray welding layer were analyzed. Results indicated that the spray welding layer produced by 160 A welding current was more uniform and was with finer organization. The main phase zone was a single γ-Fe and the fusion zone was metallurgically combined with the base metal in a planar grain manner. The hardness of the spray welding layer was the maximum when the welding current was 160 A. The abrasion resistance for each position of the spray welding layer was uniform. The γ-Fe phase zone decreased and the α-Fe phase zone increased with reduction of average hardness after the thermal stability test. In industrial tests, the optimum spray welding parameters were verified and the service life of the continuous casting segmented rollers with spray welding was 2 longer than rollers using surfacing welding process.

Source and Generation Parameters of the Granitoid Melts of the Archean Charnockite–Enderbite Complex in Karelia, with Reference to the Pon’goma-Navolok Massif

—The paper presents authors’ original detailed data on rocks of the Archean Pon’goma-Navolok charnockite−enderbite complex in northern Karelia. The rocks practically have not been modified and are preserved within a rigid block among Paleoproterozoic zones of ductile deformations and metamorphism. The geochemistry of the rocks and their isotope−geochemical features indicate that the protolith from which the enderbite melts of the main phase of the massif were derived may have been amphibolites. The enderbite melts were derived from these amphibolites under the effect of K2O-, Na2O-, and SiO2-bearing fluids; and the enderbites were subsequently charnockitized with the involvement of fluids enriched in K2O and SiO2. Physicochemical modeling indicates that the enderbite melt was derived from the amphibolite protolith at a depth of about 45 km (P = 14.8 kbar, T = 1030−1080°C) under the effect of saline H2O−CO2 fluid. Comparison of the P−T parameters of the granulite-facies metamorphism of the metabasites and the parameters under which the enderbite melts were derived indicates that Archean granulite-facies metamorphism in the Belomorian belt in northern Karelia was of contact but not regional nature and was induced by the high-temperature field of an emplaced enderbite massif. The orthogneisses hosting the Pan’goma-Navolok massif inherit geochemical features of the unsheared, ungneissose, and unmetamorphosed enderbites. This means that enderbites analogous to those of the Pan’goma-Navolok massif may have served as the protolith of some of the orthogneisses, and that enderbites may have been spread more widely in the Archean than the currently preserved single enderbite massifs.

Influence of Electron Beam Treatment on Structure and Phase Composition of TiB2–Ag Coating Deposited by Electrical Explosion Spraying

Due to many factors, the electrical explosion spraying process is not stable, which directly causes unstable coating quality and structure. Electron beam treatment may be used to improve the surface and modified structure of coatings sprayed by electrical explosions. In this study, a new TiB2–Ag metal matrix composite coating was deposited by electrical explosion spraying and modified by electron beam treatment. The prepared coatings were characterized by surface macro- and microanalysis, XDR, cross-section SEM, and TEM. The composition of the spray-coating phase differs from sample to sample. The electron beam treatment normalized the phase composition. Ag TiB2 B2O became the main phase in the modified coating. Increasing the pulse energy density and duration leads to a reduction in the low-melting Ag phase and the formation of copper contact phases due to heating and melting of the copper substrate by excess electron beam energy. The coating structure consists of a silver matrix and TiB2 inclusions. The electron beam treatment did not affect the structure; however, the microstructure of the coating transformed into a cellular crystallization structure. The silver matrix nanostructure was transformed into a nanocrystalline structure with an average crystal size ranging from tens to hundreds of nanometers.

Effect of substituting Na2O with B2O3 on the crystallization and properties of MgO–Al2O3–SiO2 transparent glass-ceramics

MgO–Al2O3–SiO2 (MAS) transparent glass-ceramics were prepared with ZrO2 as a nucleating agent, and the substitution of B2O3 for Na2O on the properties of the MAS glass-ceramics was investigated systematically. The results show that the substitution of B2O3 increased the glass transition temperature, crystallization temperature, and crystallization activation energy. Additionally, there was no change in the main crystal phase of the glass-ceramics, which were ZrO2 (JCPDS PDF#.50-1089) and Al0.52Zr0.48O1.74 (JCPDS PDF#.53-0294). The crystal growth mode shifted from three-dimensional growth to two-dimensional growth, and the crystal morphology transformed from a spherical appearance to a star-shaped appearance. Moreover, the mechanisms of the property changes induced by B2O3 substitution are revealed and discussed. The transmittance of MAS glass-ceramics without B2O3 decreased from 88 % to 32 % as the crystallization temperature increased from 800 °C to 920 °C, and decreased from 90 % to 8 % when B2O3 was added. Additionally, the Vickers hardness of MAS glass-ceramics decreased from 6.37 GPa to 6.13 GPa, after the introduction of B2O3, while, the fracture toughness increased from 1.48 MPa m1/2 to 1.55 MPa m1/2. The scratch behaviour of glass-ceramics exhibits a negative correlation with the applied load, but a positive correlation with the crystallization temperature. In particular, the incorporation of B2O3 substantially enhances the scratch resistance of glass-ceramics. The conclusions provide researchers with the roles of B2O3 in crystallization kinetics, microstructure, transmittance, and mechanical properties of MAS transparent glass-ceramics for various applications such as covers.

Determination of the number of clusters of normalized vegetation indices using the k-means algorithm

The process of clustering of normalized vegetation indices in five regions with a total area of 2565 hectares of the North Kazakhstan region was studied. A methodological approach to organizing the clustering process is proposed using the vegetation indices NDVI, MSAVI, ReCI, NDWI and NDRE, taking into account individual characteristics in the three main phases of spring wheat development As a result of the research, vegetation indices were grouped into 3 classes using the k-means clustering method. The first cluster contained vegetation indices whose maximum values occupied about 33.98% of the total area of the study area. It was found that NDVImax located in the first cluster was positively correlated with soil-corrected vegetation indices MSAVI and crop moisture indicators NDMI (R2=0.92). The second cluster is characterized by minimum values of NDVImax coefficients at the germination, tillering and ripening phases (from 0.53 to 0.55). The lowest values of vegetation indices occupied 35.9 % in the germination phase, 37.9 % in the tillering phase, and 40.1 % of the field from the total area. The third cluster is characterized by average values of vegetation indices in all three phases. A correlation matrix was also constructed to assess the closeness of the relationship between actual yield and NDVI vegetation indices. The maximum coefficient was obtained at the germination phase, R=0.94 with a minimum significance coefficient p=0.018. The approach used in this study can be useful in the analysis of satellite data, as it can improve the sensitivity of the constellation procedure. From a practical point of view, the results obtained make it possible to assess the condition of agricultural crops in the early stages of the growing season, which makes it possible to improve their productivity based on the results of cluster analysis

Magnetic properties of (Nd1-xCex) Fe11Ti alloys produce by melt - spinning process

Magnetic properties can be enhanced by doping of different elements and special preparation process which has an effect to the magnetic characteristics of NdFe11Ti alloys. The doping of Ce on the Nd site ((Nd1-xCex) Fe11Ti; with x = 0, 0.1, 0.2, 0.3 of the alloys produced by melt – spinning process have result to the proportion of the main phase with ThMn12-type structure exceeding 88 vol% of the alloys composition. The highest content of the 1:12 phase founds at, x = 0 and 0.2. However, a decrease in size of the unit cell with ThMn12-type structure phase observed due to increase in x values (x = 0 – 0.3). The impurity phase of the studied alloys found to be α-Fe. Moreover, the TEM result shows that, melt-spinning process can transform the initial multiphase alloys to an intermetallic compound with single phase of (Nd, Ce) Fe11Ti. However, the increase in coercive force and residual magnetization in comparison with that of the alloys as cast, can be explained by the increase in the dispersion of grain structure, an increase in field and the constant of magnetocrystalline anisotropy of ThMn12-type structure phase, due to the partial replacement of Nd ions with Ce ions.

Nd-doping-induced perovskite/Ruddlesden-Popper heterointerfaces boost the ORR activity and CO2 tolerance for SrFeO3-δ-based cathode

The development of cathode materials with high oxygen reduction reaction (ORR) activity is crucial to realize the wide application of solid oxide fuel cells. Nd-doped SrFeO3-δ (SNF) two-phase nanocomposite was fabricated by a dopant-induced in situ self-assembly process. The SNF nanocomposite comprises 63.4 wt% perovskite main phase (P–SNF) and 36.6 wt% Ruddlesden-Popper second phase (RP-SNF). The average thermal expansion coefficient (TEC) of SrFeO3-δ is reduced by 36.5 % and down to 13.9 × 10−6 K−1. At 750 °C, SNF demonstrates an impressive output power of 779 mW cm−2, which is twice that of the single-phase SrFeO3-δ. The superior performance stems from the heterointerface effect of the in situ self-assembled two phases. This effect increases the content of oxygen vacancies, thereby enhancing both chemical oxygen surface exchange coefficient and bulk diffusion coefficient. Moreover, the SNF composite exhibits excellent CO2 tolerance than the single-phase SrFeO3-δ. This work presents a promising avenue for exploring multifunctional materials through interface engineering, offering new possibilities for future energy conversion devices.