bluuebunny/crossref_metadata_2025 huggingface dataset:
Video conferencing software selection based on hybrid MCDM and cumulative prospect theory under a major epidemic
Authors: Xu Jie , Lv Jian , Yang Hong-Tai , Li Yan-Lai
Published: August 2021

The video conferencing software is regarded as a significant tool for social distancing and getting incorporations up and going. Due to the indeterminacy of epidemic evolution and the multiple criteria, this paper proposes a video conferencing software selection method based on hybrid multi-criteria decision making (HMCDM) under risk and cumulative prospect theory (CPT), in which the criteria values are expressed in various mathematical forms (e.g., real numbers, interval numbers, and linguistic terms) and can be changed with natural states of the epidemic. Initially, the detailed description of video conferencing software selection problem under an epidemic are given. Subsequently, a whole procedure for video conferencing software selection is conducted, the approaches for processing and normalizing the multi-format evaluation values are presented. Furthermore, the expectations provided by DMs under different natural states of the epidemic are considered as the corresponding reference points (RP). Based on this, the matrix of gains and losses is constructed. Then, the prospect values of all criteria and the perceived probabilities of natural states are calculated according to the value function and the weighting function in CPT respectively. Finally, the proposed method is illustrated by an empirical case study, and the comparison analysis and the sensitivity analysis for the loss aversion parameter are conducted to prove the effectiveness and robustness. The results show that considering the psychological characteristics of DMs in selection decision is beneficial to avoid the unacceptable and potential loss risks. This study could provide a useful guideline for managers who intend to select appropriate video conferencing software.
Grey relational analysis method based on cumulative prospect theory for intuitionistic fuzzy multi-attribute group decision making
Authors: Zhang Shanshan , Gao Hui , Wei Guiwu , Chen Xudong
Published: August 2021

The Multi-attribute group decision making (MAGDM) problem is an interesting everyday problem full of complexity and ambiguity. As an extended form of fuzzy sets, intuitionistic fuzzy sets (IFSs) can provide decision-makers (DMs) with a wider range of preferences for MAGDM. The grey relational analysis (GRA) is an effective method for dealing with MAGDM problems. However, in view of the incomplete and asymmetric information and the influence of DMs’ psychological factors on the decision result, we develop a new model that GRA method based on cumulative prospect theory (CPT) under the intuitionistic fuzzy environment. Moreover, the weight of attribute is calculated by entropy weight, so as to distinguish the importance level of attributes, which greatly improves the credibility of the selected scheme. simultaneously, the proposed method is used to the selection of optimal green suppliers for testifying the availability of this new model and the final comparison between this new method and the existing methods further verify the reliability. In addition, the proposed method provides some references for other selection problems.
Vanishing congenital lung malformations: What is the incidence of true regression?
Authors: Griggs C. , Schmaedick M. , Gerall C. , Fan W. , Orlas C. , Price J. , Simpson L. , Miller R. , DeFazio J. , Stylianos S. , Rothenberg S. , Duron V.
Published: August 2021

BACKGROUND:

A congenital lung malformation (CLM) that is diagnosed on prenatal ultrasound exam may subsequently become undetectable on later scans, a “vanishing” CLM.

OBJECTIVE:

The purpose of our study is to characterize the prenatal natural history and postnatal outcomes of “vanishing” lesions treated at our institution.

METHODS:

We performed a retrospective chart review of 107 patients diagnosed prenatally with CLM at our institution. Comparisons were made using Kruskal-Wallis or t-test for continuous variables and Fisher’s exact test or Chi-Square test for categorical variables. Multivariable analysis using logistic regression was performed.

RESULTS:

Of the 104 patients, 59 (56.7%) had lesions that became sonographically undetectable on serial ultrasound scans. Patients with lesions that vanished prenatally tended to need less Neonatal Intensive Care Unit (NICU) admission at birth (persistent CLM: 54.8%vs vanished CLM: 28.8%), decreased need for supplemental O2 at birth (persistent CLM: 31.0%vs vanished CLM: 11.9%), and decreased delay in feeds (persistent CLM: 26.2%vs vanished CLM: 8.5%) compared to those with persistent CLM. After multivariate analysis controlling for maternal steroid administration and sex, admission to NICU maintained a slight statistical significance, with patients in the vanishing CLM group 2.5 times less likely to be admitted to the NICU. None of our patients whose lesions vanished prenatally required mechanical ventilation. Eighty-six patients underwent postnatal computed tomography (CT) chest. Only 2 patients had lesions that regressed on postnatal CT.

CONCLUSION:

Lesions that vanish on prenatal imaging may be associated with improved clinical outcomes. The rate of true regression at our institution was as low as 2.3%.
Safety and efficacy of a home nasogastric monitoring program for premature infants
Authors: Vergales Brooke D. , Murray Peter D. , Miller Sarah E. , Vergales Jeffrey E.
Published: August 2021

BACKGROUND:

A novel home monitoring program, in which premature infants are cared for at home with a nasogastric tube in place prior to achievement of full oral feeding, was evaluated. The program combines a digital, fully EMR-integrated, virtual daily rounding platform with direct provider video and telephone contact.

METHODS:

A case-control study was performed evaluating infants < 34 weeks’ gestation who were followed in our program. A historical control group, was created by matching 2 : 1 based on gestational age±6 days, retroactively.

RESULT:

15 patients discharged in the program were compared with 30 controls. The home cohort gained an average of 30 g/day compared with the in-hospital group at 27g/day ( p = 0.325). The home group required a mean of 5.9±2.9 days to full oral feeding once discharged, not different from the control group at 5.4±3.7 days ( p = 0.606). The percentage of oral feeds for the home cohort, however, increased at a rate of 12.2%before discharge compared to rising 57%at home ( p < 0.001). The control group spent an additional 8.1±3.9 days in the hospital after reaching criteria. There were no reported adverse events or readmissions.

CONCLUSION:

Premature infants can safely advance oral feeds using a home monitoring program. While at home, infants gained weight similarly to their inpatient controls, yet gained full oral skills at a significantly faster rate compared to when they were in the hospital.
Physiotherapists are knowledgeable about sport-related concussion
Authors: Al Attar Wesam Saleh A. , Husain Mohamed A.
Published: August 2021

PURPOSE: Sport-related concussions (SRC) are common, especially in rugby (3.00 incidents per 1000 athletic exposures) and American football (0.08 per 1000 athletic exposures). Physiotherapists should be aware of how to assess and manage cases with SRC. The purpose of this study was to assess the knowledge of SRC among physiotherapists. METHODS: The self-administered survey consisted of 16 questions related to physiotherapists’ knowledge in managing SRC patients, case identification, and preventive measures. Countries were divided into regions based on World Physiotherapy regions. Data were analysed using a one-way Analysis of Variance (ANOVA) with Tamhane’s T2 post hoc test. RESULTS: A total of 276 male (53.4 %) and 241 female (46.6%) physiotherapists participated. The survey scores ranged from 40% to 100%, with an average score of 62.7%. A master’s degree was the highest educational qualification (46.4%) recorded. There was a difference in the score based on participant qualifications (Welch’s F (4, 58.37) = 15.03, p < 0.001). Participants with a Doctor of Philosophy (PhD) degree (73.8±14.6%) or a fellowship (73.0±19.5%) or a masters’ degree (MSc) (62.7±18.5%) obtained greater scores than participants holding a bachelors’ degree (56.7±13.8%, p < 0.001). Furthermore, there was no difference in the survey score based on participants’ region (Welch’s F (4, 143.3) = 0.08, p = 0.988). CONCLUSIONS: The results suggested that many physiotherapists worldwide are aware of the current SRC assessment and management guidelines.
Post-COVID-19 ergonomic school furniture design under fuzzy logic
Authors: Incekara Cetin O.
Published: August 2021

BACKGROUND: Because of wrong sitting position, children have back-pain and related musculoskeletal pain (MPD). Due to inappropriate designed class furniture by not taking into account the children’s anthropometric measurements have negative effect on children musculoskeletal systems. The impact of the COVID-19 pandemic crisis has changed the furniture industry’s production trends. OBJECTIVE: This study aimed to develop a new fuzzy based design of ergonomic-oriented classroom furniture for primary school students considering the measured anthropometric dimensions of students’ safety, health, well-being, i.e. ergonomic criteria, socio-psychological aspect and post-COVID policies. METHODS: In the study 2049 number of primary school students are assessed considering COVID-19 pandemic policies and their static anthropometric dimensions were measured between 7-10-year-old (between 1st-4th grade students) and descriptive statistics of children among their ages and genders are calculated; mean, standard deviation, percentiles. The data collected from the students were analyzed quantitatively by using Significance Analysis: Mann-Whitney U test statistic, t-test, Regression Analysis and one-way ANOVA. In the study interviews with experts are performed and fuzzy mathematical model (by using fuzzy-AHP, fuzzy-TOPSIS and fuzzy-VIKOR) is developed to calculate Turkey’s three schools’ furniture. RESULTS: Results showed statistically significant differences between two genders. And it is observed that the seating bench height is too high for primary school students and lower than the height of the classroom’s blackboard from the floor. Fuzzy Multi Criteria Decision Making Method’s (FMCDM) results show that primary school students’ ergonomic classroom furniture should be mainly designed by considering “COVID-19 Criteria”, “Ergonomic Criteria” and “Socio-Psychological Aspect”. Students’ existing seating benches and tables are changed by considering post-COVID policies/protocols, Ergonomic Criteria and Socio-Psychological Aspect. And a new seating bench/chair and table’s dimensions is proposed in the study. CONCLUSIONS: Children study at school for long periods and their activities involve long periods of time on their desks in schools. As per the results of the study, it can be concluded that school management must consider the genders, ages of students and take into account the post-COVID policies/protocols while procuring the classroom furniture. The COVID-19 pandemic is the single largest event to have affected children globally in their access to school in recent times; estimates suggest that over 85%of the world’s total enrolled learners, 1.5 billion children and youths, have been affected. The coronavirus pandemic also creates dramatic changes for the school furniture.
Analytical expressions for electrodynamic parameters of the shielded microstrip line
Authors: Kovalenko A. N. , Yarlykov A. D.
Published: August 2021

On the basis of an electrodynamic model of a screened microstrip line, built on the basis of the projection method using the Chebyshev basis, which explicitly takes into account the edge features of the field, a mathematical model of a microstrip line with a strip conductor was developed. The line width does not exceed the height of the substrate. In this case, the current density on the strip conductor is approximated by only one basis function. Analytical expressions are presented in the form of a sum of slowly and rapidly converging series to determine the main electrodynamic parameters of the line – wave resistance and deceleration coefficient. Due to logarithmic features, slowly converging series are summed up and transformed into rapidly converging power series. In addition, limit expressions in the form of improper integrals are given for the main electrodynamic parameters of an open microstrip line in the quasi-static approximation. Due to the logarithmic features, these integrals are also converted to rapidly converging power series. As a result, simple approximate formulas were obtained. They allow calculating the deceleration coefficient and wave impedance of the line with an error not exceeding 1%, when the width of the strip conductor is less than twice the thickness of the substrate. The results of calculating the electrodynamic parameters obtained on the basis of the developed mathematical model and on the basis of the projection method with an accuracy of up to 5 significant digits are presented. These results make it possible to establish the limits of applicability of the quasi-static approximation and to determine the error in calculating the deceleration coefficient and wave resistance using the obtained analytical expressions. The error does not exceed 0.1%, if the width of the strip conductor is less than twice the thickness of the substrate in a wide range of changes in the substrate dielectric constant and frequency.
Spatial relationships of road network and cellular coverage based on the Open Geodata: review and user case of Irkutsk Region
Authors: Podolskaia E. S.
Published: August 2021

Geographic information technologies and data are widely used to identify a variety of spatial relationships. The paper is devoted to the study of the mutual location between the road network (as exemplified by the public roads network) and cellular coverage of the Russian telecom operators on the territory of Russia. Transport researches are characterized with an emphasis of GIS projects. Then, an overview of modern web services, Open Data and Open Source developments in transport projects is made. The data, geodata services and web projects of cellular coverage for the territory of Russia are described by the examples of Russian-language sources. The practical part of the study shows the global transport accessibility raster datasets for the test region of Russia (Irkutsk Region, Siberian Federal District). An analysis of spatial relationships between roads and cellular coverages provided by VimpelCom/ Beeline, Megafon and MTS is based on the Open Data in the Open Source GIS application QGIS. Coverage varies between 63% (VimpelCom for the buffer zone of 2.5 km) and 94% (Megafon for the zone of 10 km), where 100% is the total number of cells (polygons) within the network of a respective operator in the region. We have noted that Open Data on the public road network and cellular communication for the territory of Russia differ by region, the studied communication datasets and data services do not contain significant attributive information, they consist of polygon geometry only. Frequency of their updates depends on the operating companies. The operators then provide the data for the publication to the Russian ministries and regional administrations.
Transition to Employment: A Guide for Supporting Post-Secondary Students with Disabilities
Authors:   UPEI Career Services,   UPEI Accessibility Services
Published: August 2021

This guide is a resource for supporting post-secondary institutions, namely representatives from career services, co-operative education, and disability support offices. The guide is designed to help those supporting post-secondary students with disabilities as they transition to the workforce.
Penambahan Sr pada Aluminium Paduan A356 dengan Metode Lost Foam Casting (LFC)
Authors: Suherman Suherman , Sarjianto Sarjianto , Bahri Nisfan , Sai'in Ali
Published: August 2021

Pemilihan proses pengecoran dan laju pendinginan sangat menentukan morfologi partikel autektik silicon yang dihasilkan pada aluminium paduan. Proses pendinginan aluminium paduan dengan metode pengecoran metode Lost Foam Casting (LFC) berjalan sedikit lambat sehingga menghasilkan sifat mekanis yang rendah. Tujuan penelitian ini adalah untuk mempelajari pengaruh penambahan modifier Sr pada aluminium A356 pada struktur mikro dan sifat mekanis dengan metode LFC. Aluminium A356 ditambahkan kedalam logam cair sesaat sebelum dituangkan kepermukaan pola polystyrene yang telah dilapisi bahan refaktori. Penambahan modifier Sr dipelajari pengaruhnya terhadap perubahan struktru mikro dan sifat mekanis (kekerasan, kekuatan impak dan kekuatan tarik). Hasil penelitian ini menunjukkan terjadinya perubahan partikel autektik silicon dari bentuk acicular ke bentuk berserabut. Nilai kekerasan, kekuatan tarik maksimum dan kekuatan impak meningkat masing-masing sebesar 27%, 26% dan 22% setelah penambahan.
The Effect of Quality Care on Patient Loyalty Mediated with Patient Satisfaction and Moderated by Age and Gender (Study in Outpatients at a Private Hospital)
Authors: Ricca Ricca , Antonio Ferdi
Published: August 2021

An increasingly competitive business climate and changes in patient behavior, fostering hospital managers to pay more attention in regard to factors that could affect patient loyalty. Quality care is well known as a major contributor to patient loyalty. The purpose of this study is to examine the effect of quality care on patient loyalty with patient satisfaction as the mediating variable, while age and gender as the moderators. This research model was tested empirically in outpatients at a private hospital. The results demonstrate that quality care has a significant positive effect on patient loyalty. Several managerial implications were found for hospital management to increase patient loyalty, especially considering the gender of the patient in providing services.
The Effect of Transformational Leadership and Organizational Culture on Lecturer Performance Through Innovative Work Behavior at Catholic Universities in Surabaya
Authors: Ferdinan Bernardus Aris , Lindawati Tuty
Published: August 2021

This paper aims to investigate the effect of transformational leadership and organizational culture on innovative behavior and work performance. The sample consisted of 204 lecturers from three catholic universities in Surabaya. The data were obtained from Google form and analyzed using Structural Equation Modeling (SEM) with LISREL program. The results of the study indicate that transformational leadership has a negative and significant effect on innovative work behavior, organizational culture has a positive and significant effect on innovative work behavior, innovative work behavior has a positive and significant effect on performance, transformational leadership has a negative and significant effect on performance, organizational culture has a positive effect and significant on performance, transformational leadership has a negative and insignificant effect on performance through innovative work behavior, and organizational culture has a positive and significant effect on performance through innovative work behavior. It suggests the university leaders apply appropriate leadership styles, maintain and enhance their organizational culture.
A Study on Consumer Behaviour: Transition from Traditional Shopping to Online Shopping During the COVID-19 Pandemic
Authors: Aryani Dwi Nita , Nair Rajesh Kumar , Hoo Dana Xing Yue , Hung Daisy Kee Mui , Lim Deborah Hong Ru , Chandran Dharaniya A/P Ravi , Chew Wei Ping , Desai Amey
Published: August 2021

This study aims to investigate Malaysian and Indian consumers’ preferred ways of shopping, the reasons behind their choices, and problems of transactions they faced during the pandemic. Data were primarily collected through a survey distributed to 200 respondents. The study concluded that it is unlikely for online shopping to replace traditional shopping as many consumers remain value physical examination of the products prior to purchase. However, many have opted for online shopping for its various advantages. Regardless of which method of shopping, respondents face similar problems in their transactions. The findings of this study may serve as a guideline for businesses to integrate into online shopping platforms for potential future development.
N. Rózsa Erzsébet – Hagyomány és modernitás. Az iráni külpolitika kihívásai a 21. század elején
Authors: Bosnyák Henrietta
Published: August 2021

Recenzió
A német stratégiai vízió átalakulása a 2010-es években
Authors: Altdorfer Domonkos , Csiki Varga Tamás
Published: August 2021

A tanulmány az elmúlt évtizedben elfogadott német stratégiai dokumentumok és szakpolitikai iránymutatások primer elemzésén keresztül vizsgálja a német stratégiai gondolkodás elmozdulását az aktívabb nemzetközi szerepvállalás irányába, rámutatva a 2020-as évekre kialakult stratégiai jövőkép jellemzőire is. Az elemzés elsőként az egyes dokumentumok stratégiai környezetről kialakított koncepcióját vizsgálja, azaz, hogy milyen földrajzi fókuszú és milyen jellegű fenyegetésekkel számolnak, milyen lehetőségeket látnak az érdekérvényesítésre, milyen külpolitikai eszközöket helyeznek előtérbe, milyen keretben képzelik el a honvédelmet és a nemzetközi műveleteket, illetve hogy hogyan viszonyulnak a katonai erő alkalmazásához. A vizsgált tényezők második csoportja a fegyveres erőkhöz kapcsolódóan azt vizsgálja, hogyan változott a német védelmi költségvetés 2008 óta, illetve hogy hogyan néz ki az egyes költségvetési területek finanszírozása, mi a stratégiai jövőkép a fegyveres erők használatához kapcsolódóan, illetve mik a fegyveres erők feladatkörei. Arra is kitér az értékelés, hogy a nemzetközi együttműködés fokozása megjelenik-e a képességfejlesztés területén. Mindebből átfogó képek alkotnak a szerzők a német stratégiai vízió változásáról kül-, biztonság- és védelempolitikai megközelítésben.
Gyerekkatonák a jemeni polgárháborúban
Authors: Prantner Zoltán
Published: August 2021

Jemenben napjainkra humanitárius krízis alakult ki a több éve folyamatosan zajló polgárháború eredményeként. A szemben álló felek mindegyike kihasználta a kritikus életkörülményeket, a vallási–politikai meggyőződéseket, valamint a jemeni tradíciókat, amikor intenzív toborzó tevékenységet folytattak fegyveres erejük növelésére a 18 év alatti fiatalok között, súlyosan és tudatosan megsértve ezzel a vonatkozó nemzetközi előírásokat. A tanulmány célja, hogy a statisztikai adatok szemléltetése mellett részleteiben elemezze a gyerekek csatlakozásának okait, a toborzásukra alkalmazott módszereket, kiképzésüket, és bevetésüket, valamint a mindezekkel összefüggő propagandatevékenységet. A szerző kitér a kedvezőtlen folyamat megállítására tett intézkedésekre is, valamint a gyerekkatonák rehabilitációjának problematikájára és a kedvezőtlen kilátásokra, amennyiben a jelenlegi tendencia akuttá válna.
A diszkriminációtól a rendkívüli intézkedésekig
Authors: Thomázy Gabriella
Published: August 2021

Chile célországgá vált mindazok számára, akik Latin-Amerikán belül szeretnének új hazát találni. Ilyenek a haitiak, az egyik új bevándorló csoport. A tanulmány fő célja a jelenlegi chilei tendenciák, azon belül a haiti migrációval kapcsolatos kihívások és jövőbeli szcenáriók elemzése a szektorális biztonságelmélet (koppenhágai iskola: Wæver, Buzan és de Wilde) társadalmi fókuszának segítségével, a helyzet társadalom általi biztonságiasításától egészen az állam által foganatosított rendkívüli intézkedésekig.
Kell-e készülnünk a földönkívüli civilizációkkal való találkozásra?
Authors: Dobos Gábor
Published: August 2021

Tavaly volt 70 éve, hogy Enrico Fermi megfogalmazta híres paradoxonát: ha lennének földönkívüli civilizációk, már találkoznunk kellett volna velük. Az elmúlt évtizedekben számos kísérlet történt az ellentmondás feloldására, de annak tisztázására csak alig, hogy az egyes magyarázatokból milyen stratégia következik az emberiség számára – pedig egy ilyen esemény potenciálisan a teljes megsemmisülésünkkel járhat. Jelentenek-e fenyegetést a földönkívüliek? Mit tegyünk, hogy túléljük a velük való találkozást? Az ezekre a kérdésekre adott válasz nagyban függ attól, hogy milyen magyarázatokat tartunk valószínűnek a Fermi által felvetett problémára. Ez a tanulmány nem vállalkozik arra, hogy kimerítően elemezze – vagy akár csak felsorolja – az elmúlt évtizedekben javasolt számtalan lehetséges választ, megelégszik azzal, hogy a legfontosabbakat négy nagy kategóriába rendezze, és erre építve megvizsgálja, hogy a különböző feltételezések milyen cselekvési irányt tesznek szükségessé az emberiség biztonságának megóvása érdekében.
Kim Dzsongün és Kim Dzsongün – Egy személy, két nézőpont
Authors: Háda Béla
Published: August 2021

Recenzió
Coronavirus in the Children’s World: Discourses and Drawings
Authors: Duban Nil , Şen Fatma Gül
Published: August 2021

More than 1.5 billion students and young people worldwide have been affected by school and university closings due to the COVID-19 outbreak. With the closure of schools due to the COVID-19 pandemic in Turkey, a free distance education system was launched by the Ministry of Education on 23 March 2020 with a national level television and internet-based curriculum. The opinions of the children who have just started primary school but whose school has been closed due to the pandemic in the spring term are considered to be necessary. The aim of this study was to determine the perspectives of 1st grade primary school (6.5-7 years old) students on the Coronavirus and its effects. In current study, the perspectives of 1st grade primary school students on Coronavirus and its effects were investigated. In this context, interview and document analysis techniques were used within the scope of qualitative research methods. A total of 16 primary school students from four provinces in different geographical regions of Turkey were included in the study to ensure maximum diversity. These students formed the working group of the research. In the study, semi-structured interviews and pictures drawn by students were used to reveal students’ perspectives on Coronavirus and the effects of the virus. In the research, semi-structured interviews were used for content analysis, and the pictures drawn were utilized for document analysis. In the study, it was assumed that 1st grade primary school students have the consciousness that Coronavirus has tremendous and adverse effects on human life and threatens health. it was concluded that 1st grade primary school students gained awareness about proper handwashing, using masks and gloves as a means of protection from Coronavirus.
Ежекторний детонаційний двигун на екологічно чистих компонентах палива
Authors: Сосновська Олександра Валеріївна , Золотько Олександр Євгенович , Золотько Олена Василівна , Столярчук Віталій Васильович
Published: August 2021

The subject of research in the article is engines operating on the detonation principle of converting the energy of the working fluid. In recent years, there has been an exponential growth in the number of scientific papers devoted to detonation engines, and the most promising direction is the study of detonation engines with an ejector nozzle (EN). The work aims to obtain the results of studies of the defining characteristics of a detonation engine with an ejector nozzle. The main tasks are the scientific analysis of the working process of the pulse detonation engine with EN; modeling of working processes occurring in the flow path of the engine; numerical implementation of a mathematical model and a computational experiment. Methods, for the numerical implementation of the model of a detonation engine with an ejector, a finite-difference TVD scheme of the second order of accuracy was used. According to the results of the work performed, we observe two regions on the pressure curves, within which the pressure remains unchanged for a certain time interval (pressure plateau). An increase in the length of the ejector leads to an increase in the duration of the stage of the outflow of detonation products from the flow path of the engine, an increase in the added mass of atmospheric air, and contributes to a significant increase in the specific impulse of thrust. The value of the thrust impulse was obtained by integrating the excess pressure on the traction wall over time. Conclusions. The scientific novelty is as follows. The change in pressure overtime on the traction wall of the detonation chamber when using cylindrical EHs of different lengths was investigated by the method of numerical simulation. The value of the thrust coefficient of the ejector nozzle for the starting conditions is obtained. The studies carried out in this work are aimed at analyzing the operating mode of a promising propulsion system and are aimed at modeling the gas-dynamic processes of a pulsed detonation engine with an ejector to obtain the data necessary for preliminary design, consideration of alternative design options, and an operational assessment of the possible characteristics of an engine with an ejector. The main advantages of the engine are the ultra-high-speed of energy release in the detonation process, which leads to an increase in the efficiency of the thermodynamic cycle, simplification and cost reduction of the design, and a significant gain in in-flight performance.
Вибір оптимальних методів чистової обробки лопаток закритих моноколіс турбонасосних агрегатів, отриманих адитивним методом прямого лазерного спікання порошку
Authors: Шашко Юрій Анатолійович , Кулик Олексій Володимирович , Максимчук Роман Федосійович , Санін Анатолій Федорович
Published: August 2021

The creation of complex structural elements of aircraft using is promising and is widely used since such elements have several structural and technological advantages over the manufacture of parts using classical technologies. However, it requires the solution of several scientific and technical problems to obtain products of high accuracy and roughness, the development of a technological process, the development of processing modes, and sometimes the development of a new design of products. For the development of technologies in modern rocketry, improving the quality and accuracy of the production of turbines of turbopump units, an important task is to search for new and improve existing technological solutions for the manufacture of such parts with high surface quality. The work aimed to analyze the existing processing methods for parts of turbopump units with complex geometry and select the most technologically advanced one for further use in technological processes. The objective of this article is an analytical review of existing methods of surface treatment of critical parts and the selection of the most technologically advanced method for finishing the blades of a closed-type turbine (with a shroud) to reduce the roughness and improve the quality of the working surface. The object of the research is the process of machining a segment of a turbine impeller made of Inconel 718 nickel alloy (domestic analog – alloy HN45MVTJuBR), which is a key element of a turbopump unit. The blank part of the turbine monowheel type was made using 3D printing technology. As a result of the work, the optimal processing method was chosen, namely, the DryLyte dry electrochemical polishing technology, which has quite significant advantages in comparison with illogical methods. This method has been tested experimentally and is being actively implemented abroad. To introduce this DryLyte technology, it is necessary to carry out additional experiments on finishing the inner channels of small size (24 mm) using the example of interscapular channels of turbines, which will make it possible to fully assess the capabilities of the technology.
Компактный аппаратно-программный комплекс для диагностики электронных регуляторов САУ ГТД в эксплуатации
Authors: Буряченко Анна Григорьевна , Бурунов Дмитрий Сергеевич , Немченко Ольга Владимировна
Published: August 2021

The relevance of creating a compact hardware and software complex is analyzed to ensure a full check of the operability of electronic regulators of gas turbine engines, in particular, the AI-35 engine, developed by SE "Ivchenko-Progress". The article describes the composition and functionality of the device developed by Element JSC, which was named “Complex of software and hardware for imitation of actuators and engine sensors”. The complex under consideration is intended both for autonomous use and for work as part of an automated workstation (AWS), which in turn is a part of the AI-35 engine semi-natural simulation stand. A feature of the complex is that it contains built-in mathematical models of the engine, electric drive pump-fuel regulator, as well as sensors installed on the engine. Based on the results of processing digital signals from an automated workstation or a touchscreen display, the complex generates output analog and frequency signals – rotor speed, pressure at the compressor outlet, the temperature at the compressor inlet, temperature of gases at the outlet of the turbine. The complex also generates control signals for the imitation of igniting pyro plugs and a fuel pyrovalve, in particular, it provides an imitation of their "combustion" by breaking the circuit. The built-in touchscreen display makes it easy for the operator conducting the governor and engine tests to use the complex as intended. With the help of the display, without using a PC, the operator can manually control the process of simulating the issuance of a command to start the engine by changing the values of the rotor speed, form various modes of engine operation, setting the appropriate parameters, simulate engine surge, etc. The functionality of the developed complex provides debugging of GTE control algorithms and subsequent tests of the regulator.
Simulation of the business processes of the developing enterprise to create complex products with multi-level component architecture
Authors: Федорович Олег Євгенович , Прончаков Юрій Леонідович , Єлізєва Аліна Володимирівна , Лещенко Юлія Олександрівна
Published: August 2021

The problem of research of business processes related to the organization and management of projects to create the new complex technical products in aerospace, shipbuilding, and other fields of mechanical engineering is stated and solved. The relevance of the study is related to the planning of a set of business processes, taking into account the architectural representation of the complex product being created. The study aims to develop a new method of synthesis of the multilevel complex of business processes to manage the creation of new technology, taking into account the multi-component representation of the complex product architecture. Much attention is paid to the complex product architecture, which is presented as a set of interconnected components. The following component types are outlined: components that can be reused; components that can be adapted to the requirements of the new product; innovative components. The types of components are studied in terms of the building of the set of business processes on their creation, taking into account the main indicators (costs, execution time, risks). Using the positive experience of past developments in the form of ready-to-use business processes helps to minimize the risks, and the new business solutions in their turn ensure the competitiveness of the complex product. The information base of positive past business processes in the form of precedents base is being built. The precedents base is used to find the close analogs of ready-to-use business processes. The set of business processes related to the management of complex product creation is formed. It has a multilevel representation that fully corresponds to the tree-like component architecture of the complex product. The method to synthesize the complexity of business processes that are planned to perform the tasks on the management of projects on creation of complex products for the developing enterprise is constructed. It is based on the “from top to bottom” system design principle. The optimization model to find the minimum costs, time, and risks in the process of business processes creation that takes into account the multilevel structure of the business process is built. The simulation event-based model in the form of a related agent set is used to study the successful execution of planned business processes related to the creation of the complex product. The results of this study should be used in the practice of creating innovative technical products that have a complex multi-level component architecture for the organization and planning of business processes related to development management. Mathematical methods used: systems analysis, precedent theory, lexicographic ordering, component design, integer optimization, simulation modeling.
Теплофизические характеристики теплозащитного пакета корпуса ракетного двигателя при программированном нагреве
Authors: Евдокименко Юрий Игоревич , Гусарова Ирина Александровна , Фролов Геннадий Александрович , Кисель Вячеслав Михайлович , Боровик Дмитрий Валериевич , Бучаков Сергей Васильевич
Published: August 2021

An experimental determination of the temperature dependences of the thermophysical characteristics of the MFP-92 multifunctional coating in the operating temperature range under thermal loading, simulating standard flight conditions, has been carried out. Heating was carried out with a jet of an industrial oxygen-propane burner mounted on a tripod with the possibility of varying the distance to the surface of the sample. The programs of the material operating modes include two peaks of heating to a temperature of ~1400 ° C with a heating and cooling rate of 20 - 40 deg / s. Under such conditions, thermal degradation of the MFP-92 material occurs, which changes its phase composition, structure, and, accordingly, thermophysical characteristics (TPС). The main transformations in the MFP-92 material occur in the temperature range up to 1000 °C, therefore, the heat transfer in it for given heating programs can be described using a simplified TРС model. This model assumes the existence of material in two states - initial (phase A) and annealed with completely completed transformation processes (phase B), each of which is assigned its own set of TPC. To determine the TPC of the MFP-92 material in its samples during thermal testing, temperature fields were recorded, which were then processed using the method of solving the inverse (coefficient) problem of thermal conductivity on a computer model. As a result, the temperature dependences of the specific heat and the coefficient of thermal conductivity of phases A and B were obtained, as well as the value of the most powerful thermal effect of the phase transition at 110 °C in phase A. The remaining phase transitions were taken into account by the corresponding changes in the specific heat. During material testing, the emissive of the material is also determined. Verification of the two-phase model of the MFP-92 material and the obtained values of its TPC was carried out based on the temperature fields obtained during the thermal tests of the samples of the three-layer thermal protection package "MFP-92 material-thermal insulation-steel substrate" under heating conditions according to the operating mode program confirmed their adequacy.
Методи діагностування дефектів деталей авіаційних двигунів з композиційних матеріалів
Authors: Пальчиковський Володимир Олександрович , Морозов Андрій Володимирович , Торба Юрій Іванович
Published: August 2021

The key priority in improving the technical and economic performance of gas turbine engines lays in the use of new composite materials. The use of composites in the components of critical load-carrying structures operating under static and dynamic loads during long service lives determines the need to predict the component lives. Also, in order to increase the safety of engine operation and improve the parts manufacturing process, timely defect detection in such structures is of great importance. This article is devoted to the detection of the composite parts defects and damages that occur at different stages of manufacturing and operation. The aim is to investigate the existing methods of non-destructive testing of composite materials, describe their functional concept, and determine the field of their application. The article considers acoustic, thermal, optical, and radiation testing methods. Among the acoustic methods, the phased array method is selected as the most informative and multipurpose. The acoustic emission method is also selected; it will allow real-time monitoring of defect growth during testing. Out of thermal methods, the vibrothermography method was selected as the most advanced among the thermographic sub-methods. It allows using the phenomenon of local defect resonance and thus ensures effective defect detection. Shearography is selected for investigation out of optical methods. The special aspects of the use of X-ray methods are considered through the example of X-ray computed tomography. It is concluded that the approach combining several methods can significantly increase the efficiency of defect detecting and help to assess their criticality. Active thermal testing is well suited for fast scanning of large-sized parts and searching for areas of defect accumulation. In the following, local methods, such as impedance, vibrothermography, or one of the ultrasonic, should be used. To measure deformations under static load, it is a good practice to use shearography. To identify progressive defects under static load, it makes sense to use the acoustic emission method.
Анализ сертификационных требований к организации-разработчику изделий гражданской и государственной авиации
Authors: Маринина Анна Николаевна , Степаненко Сергей Михайлович , Харченко Виталий Григорьевич
Published: August 2021

Certification of developers, manufacturers and aviation equipment for civil aviation is carried out by the State Aviation Administration of Ukraine in accordance with the requirements of the Aviation Regulations APU-21 (Part-21). Certification of developers, manufacturers and aviation equipment for state aviation is carried out by the Department for Regulation of State Aviation of Ukraine in accordance with the requirements of the certification rules of Part-21B. Part-21B certification rules use the principles of EASA Part-21, EU Commission Regulation N 748/2012, as well as the European Military Airworthiness Requirements EMAR 21, approved by the Military Airworthiness Forum under the auspices of the European Defense Agency. The article presents the results of a comparative analysis of certification requirements for state aviation in accordance with Part-21B and for civil aviation in accordance with APU-21 (Part-21). Such an analysis makes it possible to identify differences that must be taken into account in quality management procedures in order for the enterprise to obtain developer, manufacturer and type certificates for both civil aviation equipment and state aviation equipment. The degree of coincidence of the requirements in Part-21B and in APU-21 (Part-21) is classified as follows: identical, overlapping, conflicting, completely different, the absence in one of the rules. When registering the analysis results, a graphical form was selected for visualizing numerical information in the form of a "Radar" diagram. It was concluded that the results of comparing the requirements in the field of obtaining a certificate of the development organization in accordance with Chapter J, type certification in accordance with Chapter B, approval of changes in the design of aviation equipment in accordance with Chapter D show that the requirements of the certification rules of Part-21B and the Aviation rules of the APU- 21 (Part-21) for the most part do not contradict each other and have few differences. This allows the enterprise to have a limited amount of differing evidentiary documentation to meet the certification needs of a developer, manufacturer and aircraft for civil and state aviation.
Удосконалення процесу сумішоутворення в камерах згоряння теплових двигунів
Authors: Морозова Ирина Владимировна , Терещенко Юрий Матвеевич
Published: August 2021

Improving the mixture formation and combustion of various types of fuels in the combustion chamber is one the ways for the development of modern engines. Requirements for reliability, durability, tactical and technical characteristics and, importantly, for environmental friendliness pose new problems in this area of science and technology. This is largely determined by the degree of perfection individual processes in the engine operating cycle. An increase in power in accordance with the requirements for an increase in energy saturation and productivity of transport vehicles is limited by the resource and reliability of the engine due to an increase in thermal and mechanical loading of the main parts. The expansion the scope of application is limited by increased emissions harmful substances with exhaust gases, levels noise and vibration a running engine. Consumption increasing amounts liquid fuels requires further improvements in fuel efficiency. The main process of the working cycle a piston engine is the process fuel combustion. Fuel efficiency, power, service life and environmental performance depend on its quality. Therefore, the greatest attention is paid to the improvement of this process. The development of modern engines consists in the study and improvement of the working process on liquid and gaseous fuel components. Based on the foregoing and in accordance with the urgency of this problem, the method of electromagnetic action on fuel was studied. The results of experimental studies have shown the effectiveness the use of electro physical effects on hydrocarbon fuel to improve the parameters and characteristics of heat engines. It has been established that the electro physical effect on hydrocarbon fuel increases the completeness of fuel combustion by 4 ... 6% and reduces the deposition of carbon deposits in the combustion chamber of a gas turbine engine by 20 ... 25%. Improvement the fuel combustion processes in the previous phases leads to a reduction in the afterburning phase, which entails a decrease in the exhaust gas temperature, a decrease in the concentration of carbon monoxide by 0.64 ... 0.7%, the concentration of hydrocarbons by 25 ... 35% and the concentration of nitrogen oxide by 12 ... 16%.