bluuebunny/crossref_metadata_2025_split huggingface dataset:
Az alsó végtagi varicositas spontán rupturája
Authors: Bihari Imre , Bihari Anna , Bihari Péter 
Published: May 2024

Bevezetés: Az alsó végtagi varicositas spontán rupturájából
származó vérzés az alapbetegség ritka, riasztó, esetenként halálos szövődménye.
Célkitűzés: Az alsó végtagi varicositasból származó spontán
vérzés előfordulási gyakoriságának, a vérzésforrás mibenlétének és
elhelyezkedésének, valamint az ellátás részletkérdéseinek vizsgálata.
Módszer: Betegeinknél fizikális és ultrahangvizsgálatot
alkalmaztunk a vérzés hátterében fennálló kóros állapotok meghatározására. A
leletek összesítéséhez és feldolgozásához a Microsoft Office szoftvert
alkalmaztuk. Tanulmányunk egyetlen centrum eredményeinek retrospektív
feldolgozását tartalmazza. Eredmények: Saját, 25 000 betegre
vonatkozó anyagunkban spontán varixruptura 0,26%-ban fordult elő. Ezt az ország
felnőtt népességére kivetítve: évente átlag 659,7 esettel kell számolni. Inkább
a középkorúakat és az időseket érinti (átlag: 56,8 ± 15,3 év), több férfit
(59,5%), mint nőt. Gyakrabban a boka-lábfej tájon fordul elő (60,5%). Meglepően
a kisebb méretű, kb. 1 mm átmérőjű, vékony falú ereket érinti, nem a
vastagabbakat. A háttérben mindig varicositas, illetve krónikus vénás
elégtelenség áll. Azonnali ellátásra inkább a nyomókötés javasolt. A definitív
ellátás sclerotherapiával történik, a korábban alkalmazott aláöltés helyett. Az
öltés helyén ugyanis gyakran fekély alakul ki. Végleges megoldásra és
prevencióra radikális varicectomia javasolt. Következtetés: A
korábban csak esztétikai eltérésnek tekintett, kb. 1 mm átmérőjű, alsó végtagi
vénák jelentős, olykor halálos vérzést okoznak. Ez a szövődmény, bár ritkán
fordul elő, de a vénás betegségek gyakorisága alapján ellátására a sürgősségi
ellátásban részt vevőknek fel kell készülniük. A vénás betegséggel foglalkozók
részére – akár megelőzési, akár végleges kezelési céllal – endovénás vagy
hagyományos sebészi beavatkozás javasolt. Orv Hetil. 2024; 165(18): 711–716.
Influence of electrochemical hydrogen charging on the mechanical, diffusional, and interfacial properties of an amorphous alumina coating on Fe-8 wt% Cr alloy
Authors: Gopalan Hariprasad , Rao Jing , Patil Piyush , Jung Chanwon , Kim Se-Ho , Goodrich Silas , Wetegrove Marcel , Kruth Angela , Scheu Christina , Dehm Gerhard , Duarte Maria Jazmin 
Published: May 2024

AbstractAmorphous alumina coatings, intended as hydrogen barriers, were successfully deposited on Fe-8 wt% Cr substrates by plasma ion-assisted deposition technique. The amorphous structure of the coatings was confirmed by transmission electron microscopy and X-ray diffraction. The interfacial and mechanical properties of the coating-substrate system were evaluated using an in-house custom-designed backside electrochemical hydrogen charging method. In this approach, the substrate side faces the electrolyte (hydrogen entry side) and the mechanical behavior was tested on the coating side (hydrogen exit side). A Kelvin-probe-based measurement was performed to determine the hydrogen diffusivity in these amorphous alumina coatings at room temperature using a similar backside charging approach. Chemical and microstructural characterizations, in combination with scratch and hardness testing, show that interfacial hydrogen accumulation is strongly responsible for drastic changes in the scratch morphology of the coating and its adhesion to the substrate. Scratch testing promises to be a quick and easy technique to fingerprint changes at the coating/substrate interface upon hydrogen exposure.
Graphical abstract
Identification of an algorithm for the analysis and study of urban road network trajectories
Authors: Naizabayeva Lyazat , Turken Gulzat , Abdiakhmetova Zukhra , Temirbekova Zhanerke , Satymbekov Maxatbek 
Published: May 2024

The object of this study is a clustering algorithm using various technologies.
This paper compares clustering algorithms that are more commonly used to analyze urban road network trajectories, the growth curve model, with the elbow method and the x-means algorithm. Experiments were conducted with various volumes of big data to determine calculation time, accuracy, and ways to increase calculation time. These results can be used to manage traffic jams in congested areas and city streets. Considering the widespread use of clustering algorithms for solving various problems, this study proposes to introduce GCM, SPGK methods for monitoring and analyzing the state of congestion on city roads. The work was carried out in the following steps: research and selection of methods based on efficiency and time, implementation of parallel computing technologies to improve computation speed, demonstration of the selected method based on collected data from a real city with visualization of the results. The growth curve model algorithm has been proven to be almost 5 times more effective than the elbow method and the x-means algorithm. The time allocated for data processing has been calculated. An increase in the volume of processed data showed an almost stable execution time t = 3 s for the GCM algorithm for data with a volume of up to almost 2,000 units. The effectiveness of SPGK-means was shown for different values of the number of points. Models of the Chengdu transport network obtained using a clustering algorithm with maximum grid density of neighborhoods are presented. There are some deviations between the grid and the road network due to the large grid size. This error is explained by an error of up to one between the points and the real grid.
The results obtained clearly show how optimization of congested roads can be influenced. They provide information to obtain data on available routes, which allows you to analyze the road network individually and as a whole
Reducing the volume of computations when building analogs of neural networks for the first stage of an ensemble classifier with stacking
Authors: Galchonkov Oleg , Baranov Oleksii , Chervonenko Petr , Babilunga Oksana 
Published: May 2024

The object of research in this work is ensemble classifiers with stacking, intended for the classification of objects in images with the presence of small sets of labeled data for training. To improve the quality of classification at the first stage of such a classifier, it is necessary to place more primary classifiers that differ in heterogeneous structured processing. However, the number of known neural networks with appropriate characteristics is limited. One approach to solving this problem is to build analogs of known neural networks that make classification errors on other images compared to the base network. The disadvantage of the known methods for constructing such analogs is the need to perform additional floating-point operations. The current paper proposes and investigates a new method to form analogs through random cyclic shifts of rows or columns of input images. This has made it possible to completely eliminate additional floating-point operations. The effectiveness of using this method is explained by the structured processing of input images in basic neural networks. The use of analogs obtained by the proposed method does not impose additional restrictions in practice. This is because the heterogeneity of structured processing in basic neural networks is a typical requirement for them in an ensemble classifier with stacking.
The simulation for the CIFAR-10 data set demonstrated that the proposed technique for constructing analogs allows for a comparative quality of classification by the ensemble classifier. Using MLP-Mixer analogs provided an improvement of 4.6 %, and CCT analogs – 5.9 %
Devising a scientific-methodical apparatus for the appropriate distribution of damaged weapons among specialized repair and restore units
Authors: Maistrenko Oleksandr , Khoma Vitalii , Kurban Volodymyr , Rakhmanyi Oleksandr , Shvets Mykola , Stehura Serhii , Horbenko Serhii , Pochynok Serhii , Isenko Vitaly , Kuznetsov Valeriy 
Published: May 2024

The object of this study is the process of distribution of damaged weapons and military equipment of various types among specialized repair and restoration units.
The problem being solved is the lack of adaptability of the existing scientific and methodical apparatus to the expedient distribution of damaged weapons and military equipment of various types among specialized repair and restoration units.
An algorithm for the expedient distribution of damaged weapons and military equipment among specialized repair and restoration units is proposed, which is based on the method of non-linear programming (the method of two functions). The essence of the developed algorithm is to take into account the non-linearity of objective functions of both the consumer and the resource.
A feature of the developed algorithm of expedient distribution is taking into account the heterogeneity of both damaged weapons and military equipment, as well as the specificity of repair and restoration units.
The scope of practical application of the proposed algorithm is management processes in military hostilities during combat operations.
The procedure for appointing specialized repair and restoration units for the restoration of damaged weapons and military equipment has been improved.
The peculiarity of the proposed procedure is that it is based on the distribution of damaged weapons and military equipment not only on the basis of the capacity of certain repair and restoration units but also taking into account their compliance. The specified procedure makes it possible to select those repair and restoration units that could allow for an increase in the level of restoration of damaged weapons and military equipment by 20 %.
The scope of practical application of the improved procedure is the management processes of the technical support system of troops when planning measures to restore damaged weapons and military equipment
Determining directions for transforming the organization's competence structure depending on its life cycle stage in the context of enabling effective operation in the market
Authors: Gruzina Inna , Lepeyko Tetyana , Lohinova Kateryna , Pererva Ivanna , Myronova Olga 
Published: May 2024

The object of research is the process of functioning of organizations at different stages of the life cycle (LC). Papers addressing the management of organizations ignore the need for them to acquire competence to successfully solve the tasks of each stage. This directed the research to the definition of priority management tasks, determined by the nature of activity at different stages of LC, and the competencies necessary for their solution. The directions of the transformation of the structure of organizational competence due to the change in the frequency of reference by heads of organizations to its members in the process of solving tasks have been determined. The importance of functional and basic component competencies at the birth stage was noted (36.7 and 38.7 % of reference in the total number). The increase in the frequency of reference to the competencies of synergistic, key, and strategic components (3.4; 2.2; 1.66 times) at the stage of intensive growth is explained by the organization gaining authority in business circles, the possibility of its use for lobbying organizational interests. Among the competences at the stage of maturity, representatives of the synergistic and functional components prevail – the increase in the frequency of reference by 1.44 and 1.1 times, respectively. The share of reference to the competences of the basic component is also high (40 %). At the stage of decline, functional and basic competencies remained important (36.9 and 39.5 %), in particular, the competencies of managers in ensuring the most painless liquidation of the organization.
A distinctive feature of the study is the addition of the procedure for determining the stage of LC with a list of priority tasks and the competencies necessary for their solution. This made it possible to understand the directions of the transformation of competence, to identify the need for the development of competences due to the organization's position on the life cycle curve or its change
Determining the effect of laboratory testing conditions on working parameters of the ST-25 hall thruster
Authors: Petrenko Olexandr , Pererva Viktor , Maslov Viktor 
Published: May 2024

The object of this study is the ST-25 Hall thruster with limited discharge power, no more than 200 W, designed by Flight Control LLC (Ukraine). The problem that was solved in the current paper was to determine the effect of residual gas pressure in vacuum chambers on the operating parameters of the Hall thruster. To solve this task, the operating parameters of the ST-25 thruster were determined, which was tested in three vacuum chambers with different sizes of residual pressure. As a result of the laboratory study into the operating parameters of the ST-25 thruster, the volt-ampere characteristics of the engine discharge at fixed values of the working gas (xenon) flow rate were obtained. The dependences of the engine thrust on the mass flow rate of the working gas at fixed values of the discharge voltage were derived. Based on the experimental data, the dependences of the specific impulse of the engine anode unit on the discharge voltage, as well as the dependence of efficiency of the engine anode unit on the discharge voltage were calculated. The studies showed that when the residual pressure in the vacuum chamber is reduced by 2–3 times, the operating parameters of the engine increase by 15–20 %. Such a reduction in residual pressure increases thrust by 25–40 %. Special feature of the results is the determination of threshold values of residual gas pressure in vacuum chambers during experimental studies, in which the operating parameters of the Hall thruster are similar to its operating parameters under space conditions. This work’s findings could be used in practice when conducting experimental studies of electric rocket engines, when it is necessary to estimate the operating parameters of Hall thrusters that will be obtained under actual space conditions
Improving a method for detecting stealth aerial vehicles by using a network of two small-sized radars with decentralized information processing
Authors: Khudov Hennadii , Zvonko Andrii , Kostyria Oleksandr , Myroniuk Mykola , Bashynskyi Dmytro , Solomonenko Yuriy , Irkha Artem , Dudar Yevhen , Snitkov Kostiantyn , Polishchuk Andrii 
Published: May 2024

The object of this study is the process of detecting stealth aerial vehicles by a network of two small-sized radars with decentralized signal processing. The main hypothesis of the study assumed that combining two small-sized radars into a network could improve the quality of detection of stealth aerial vehicles with decentralized signal processing.
The improved method for detecting a stealth aerial vehicle by a network of two small-sized radars with decentralized processing, unlike the known ones, provides for the following:
– each radar emits its own probing signal;
– each radar receives only its own signal;
– coordinated filtering in the reception system of each radar of its signal;
– quadratic detection of its signal in each radar;
– finding the sum of detected signals in each radar at the output of its matched filter;
– preliminary detection of the signal is carried out by each radar separately;
– in each range element, the signal is compared with the threshold level;
– when the threshold level in the range element is exceeded, such range element is assigned a value of one, otherwise – zero;
– the sequence of zeros and ones obtained in this way in each radar of the network is transmitted to the central processing point;
– at the central processing point, a decision is made about the presence or absence of a stealth aerial vehicle in the range element. Such a decision is made based on the results of the combined processing of binary sequences coming from the radars according to the "k out of m" criterion.
It was established that when detecting a stealth aerial vehicle by a network of two small-sized radars, decentralized information processing provides a higher value of the conditional probability of correct detection, by (19–26) % on average
Effect detection of using a modified Redlich-Kwong-Aungier equation of state on the calculation of carbon dioxide flow in a centrifugal compressor
Authors: Vorobiova Hanna , Dolmatov Dmytro , Fesenko Kseniia , Sysoiev Iurii , Dehtiarov Oleh , Ivashchenko Maryna 
Published: May 2024

Supercritical CO2 (S-CO2) cycles have found applications in power generation and can achieve high efficiency in a wide range of temperatures and pressures. The Redlich-Kwong-Aungier real gas equation of state is used to describe the thermodynamic properties of the CO2 working fluid. The main problem in its application lies in modeling the phase transition between different states and the region near the critical point of the working fluid.
The object of the study is the working process in a centrifugal compressor located in the compression loop with the CO2 working fluid. The proposed mathematical model of the modified Redlich-Kwong-Aungier equation of state allows for a first-order phase transition from the liquid to the supercritical region even near the critical point. A scaling factor was added to the modified equation of state, significantly reducing the error in pressure determination in a wide range of temperatures compared to the original equation of state. The proposed mathematical model can be applied in the pure liquid region, limited to the temperature range from 220 K to 300 K.
The mathematical model was used to solve the 3D gasdynamic problem, specifically to determine the thermodynamic and kinematic properties of the flow in a centrifugal compressor in a wide range of operating modes. A comparison of the calculation results with experimental data from the Sandia National Laboratories (USA) report was conducted. A satisfactory agreement of the results at the design point of the compressor characteristic was obtained (less than 5 % discrepancy).
Due to the simplicity of the equation of state and the small number (seven) of empirical coefficients, the obtained mathematical model can be used for practical CFD tasks without significant computational time costs.
Indirect temperature protection of an asynchronous generator by stator winding resistance measurement with superimposition of high-frequency pulse signals
Authors: Nurmaganbetova Gulim , Issenov Sultanbek , Kaverin Vladimir , Em Gennady , Asainov Gibrat , Nurmaganbetova Zhanara , Bulatbayeva Yuliya , Kassym Ruslan 
Published: May 2024

The article deals with the indirect methods for calculating the temperature of asynchronous generators with the introduction of a pulse component in the power supply circuit of the stator windings of asynchronous generators with squirrel-cage rotor. The relevance of this issue is determined by the need to improve asynchronous energy converters to increase their reliability and safety.
The object of the study is an asynchronous generator with squirrel-cage rotor, which consume 40 % of the total electricity generated, and are the most affordable. One of the dangerous modes of asynchronous generators is their overheating as a result of increased currents and temperatures.
The thermal protection of the stator winding of asynchronous generators relies primarily on measuring or determining the winding temperature.
An indirect method for determining temperature based on measuring the resistance of the stator of an asynchronous generator with squirrel-cage rotor is proposed. The method is based on superimposing pulse signals of small amplitude and high frequency of 600 Hz on an alternating sinusoidal voltage with a frequency of 50 Hz. A simulation model for a 3 kW asynchronous generator has been developed. There were given the simulation results. The estimated values of the active resistances of the stator can be used to indirectly determine the temperature of the windings in thermal protection devices of asynchronous generators, as well as for control, monitoring and diagnostics of the technical condition. The research results confirm the possibility of indirect temperature determination and the creation of a thermal protection system for asynchronous energy converters based on the use of estimation methods.
Application of anterior bilateral sacrospinous fixation in the treatment of apical genital prolapse
Authors: Popov A. A. , Gadzhieva S. A. 
Published: May 2024

Aim: to increase the clinical effectiveness and safety of apical prolapse treatment by applying anterior bilateral sacrospinous fixation (SSF) with a polypropylene mesh implant.Materials and Methods. A single-center open prospective comparative clinical study in parallel groups in parallel groups was carried out at the Clinic of Academician Krasnopolsky Moscow Regional Research Institute of Obstetrics and Gynecology. There were examined and treated 155 patients with stage II–IV symptomatic genital prolapse according to the Pelvic Organ Prolapse Quantification System (POP-Q) who underwent various variants of SSF. The patients were stratified into 3 groups: group 1 (LPSSF) – 34 patients with symptomatic apical genital prolapse who underwent SSF through the posterior vaginal wall using LPSSF ligatures (ligature posterior sacrospinous fixation); group 2 (LASSF) – 42 patients with symptomatic apical or anterior-apical genital prolapse, who underwent ligature SSF using the anterior approach LASSF (ligature anterior sacrospinous fixation); group 3 (MESH TASSF) – 79 patients with symptomatic apical or anterior-apical genital prolapse, who were treated by applying the anterior bilateral SSF method using synthetic tape MESH TASSF (tape anterior sacrospinous fixation). The frequency of intra- and postoperative complications, patient complaints, and relapse rates were assessed post-surgery. Functional outcomes were assessed using the PFDI-20 questionnaire (Pelvic Floor Distress Inventory-20) at 3, 6 and 12 months after treatment. Patients in group 3 were treated by applying a method we developed for correction of apical genital prolapse and concomitant cystocele reconstruction.Results. The method presented here was characterized by a lower blood volume loss compared to posterior SSF, minimized intra- and postoperative complications: decreased incidence of hematomas, buttock pain, rate of urinary disorders (stress incontinence, mixed forms of urinary incontinence, urgent urinary incontinence, urinary difficulty, bladder hypotension). Applying MESH TASSF fixation allowed to decrease duration of hospital treatment and alleviate pain severity in the postoperative period, and additionally contributed to improved patients' quality of life sustained for as long as 12 months post-surgery.Conclusion. The treatment results confirmed that the MESH bilateral SSF method using an anterior approach is clinically effective, relatively safe, and contributes to a markedly reduced rate of disease relapses. The presence of anterior-apical or apical genital prolapse (C or Ba+C prolapse, stages II–IV according to the POP-Q) should be considered as indications for performing anterior bilateral SSF.