bluuebunny/crossref_metadata_2025 huggingface dataset:
DESEMPEÑO DEL MODELO DE LOTKA-VOLTERRA Y HOLLING APLICADO A SISTEMAS PRESA-DEPREDADOR
Authors: Gutiérrez-Borda Alberto Ernesto
Published: September 2022

En este trabajo se demuestra computacionalmente la condición crítica del modelo Lotka-Volterra, partiendo de la suposición formal de crecimiento presa-depredador en relación 1:1, utilizando el método Runge-Kutta y asumiendo valores hipotéticos de las constantes fijas positivas A (tasa de crecimiento de la presa), B (tasa a la que los depredadores destruyen a la presa), C (tasa de mortalidad de los depredadores), y D (tasa a la que los depredadores aumentan al consumir presas respectivamente); interactuando entre sí en el ecosistema, de forma tal que se estimó la dependencia de las variables x(presa) e y(depredador) en función del tiempo a través de los diferenciales dx/dt y dy/dt. Se consideró también un modelo depredador-presa de respuesta funcional de tipo II de Holling, observando que el depredador presentó una saturación y fue necesario un período de tiempo para la captura, según las curvas diferenciales de trayectorias y campos de dirección; el resultado concluyente es la variable presa que se superpone a la variable depredador, ajustándose los valores a una colinealidad en función del tiempo. Este estudio tuvo como objetivo implementar el Modelo de Lotka-Volterra y Holling para ser aplicado a sistemas presa-depredador.
A proposal for estimating intensity functions in a three-state model in the presence of arbitrary censoring
Authors: Rosales Cerquera Luisa Fernanda , Iral Palomino René , Mazo Lopera Mauricio Alejandro , Salazar Uribe Juan Carlos
Published: September 2022

Multi-state are useful tools to model the dynamics of recurring processes over time or some changing phenomenon over time. This paper presents a methodology to estimate time-dependent intensity functions in the presence of interval censoring and right-hand censoring when considering a three-state model like the disease-death one. The likelihood function is deduced mathematically, which incorporates information that has been collected longitudinally, as well as the different modes of censoring. This likelihood should be optimized numerically with the help of a Gauss quadrature since in that expression there is an integral which is related to censored units. A piecewise function-based method is explored through a simulation study to obtain an estimate of the intensities.
Salicylic acid, cinnamaldehyde, and thymol incorporated into cassava starch coatings for mango preservation
Authors: Santacruz Stalin , Coloma Hurel José
Published: September 2022

Mango is a fruit consumed all over the world. There are some methods used during storage such as modified atmosphere, hot steam, irradiation, wax coating, and immersion in hot water to extend mango shelf life. However, heat treatment accelerates maturation and reduces organoleptic quality. Edible coatings are also used to extend the shelf life of food. Edible coatings are layers made of proteins, polysaccharides, lipids, antimicrobial components, antioxidants, or a mixture of them. Additives with antimicrobial, antioxidant, or other properties, are added to coatings to improve their functionality. Coatings improve food quality by slowing down unwanted changes and extending shelf life. Knowing that starch is not the best material for preparing edible coatings, in the present work, it was modified by adding salicylic acid or a cinnamaldehyde-thymol mixture to the cassava starch coating-forming solution. Cassava starch or chitosan coatings were applied to Tommy Atkins mangoes. Total soluble solids, titratable acidity, weight loss, and instrumental texture (firmness) were determined over four weeks of storage at 12 °C and 90% of relative humidity. Mangoes coated with cassava starch containing salicylic acid (SSA) had the highest weight loss, while fruits coated with starch-cinnamaldehyde-thymol (SCT) had the lowest weight loss during the whole storage time. The titratable acidity showed a decrease throughout the four weeks of storage. However, in the third week of storage, mangoes coated with chitosan, SSA, and SCT samples ripened more slowly, as indicated by higher acidity than uncoated samples. The SSA and chitosan-coated mangoes showed statistically similar penetration forces that were also higher than the SCT and uncoated samples. Cinnamaldehyde-thymol improved the hydrophobic characteristics of the starch coatings and therefore, it reduced the weight loss of mango during storage.
Delimitación automática y análisis morfométrico de cuencas y subcuencas usando un conjunto digital de datos de elevación en la jurisdicción de Cornare, Antioquia, Colombia
Authors: Pérez López Astrid Elena , Ferreira Melo Valdinar , Fernandes Filho Elpídio Inácio , Rocha Francelino Marcio
Published: September 2022

Los parámetros hidrológicos y morfométricos de una cuenca constituyen estimaciones que deben realizarse sobre un mapa con suficiente información. La recopilación de esta in situ se ha visto limitada por problemas de orden público. Entre los índices morfométricos de una cuenca se encuentra el índice de circularidad (Ic), que hasta el momento no ha sido calculado para las cuencas en estudio. La delimitación automática de cuencas realizada a partir de Sistemas de Información Geográfica (SIG), ha permitido la investigación y manejo de las mismas debido a la eficiencia en el procesamiento de datos, facilidad y bajo costo, además de la creciente disponibilidad de imágenes y bases de datos. El objetivo de este trabajo fue evaluar la metodología propuesta para utilizar el Modelo Digital de Elevación (MDE) SRTM de la jurisdicción de la Corporación Autónoma Regional de las Cuencas de los Ríos Negro y Nare (Cornare) y extraer de este el drenaje numérico, para delimitar cuencas y subcuencas, así como calcular índices, tales como densidad de drenaje (Dd) e Ic. El mapa de declividad mostró terrenos con relieve muy suave a muy fuerte. La delimitación automática de cuencas con base en el orden de drenaje ≥ 6 fue la que más se acercó a la realidad; en cuanto a la delimitación de subcuencas, fue aquella con base en el orden ≥3. Los índices Dd e Ic, indicaron que las subcuencas tienen drenaje, nivel de escorrentía y capacidad de infiltración moderados y tienden a ser más alargadas que circulares.
Evolúciós pszichológia: Miért és hogyan tanítjuk?
Authors: Meskó Norbert , Gyuris Petra , Putz Ádám , Kocsor Ferenc , Bereczkei Tamás
Published: September 2022

Az evolúciós pszichológia (EP) a viselkedéstudományoknak az emberi viselkedés evolúciós gyökereire fókuszáló ága. Képviselői abból indulnak ki, hogy az ember pszichológiai (kognitív, affektív, társas stb.) működése alaposabban megérthető, ha figyelembe vesszük, hogy az egyes pszichológiai vonások milyen szelekciós előnyt jelenthettek az ember evolúciója során. Számos tudományos irányzatot szintetizál, így például felhasználja a kognitív pszichológia, a genetika, az etológia, az antropológia, a viselkedésökológia és a szociobiológia megközelítésmódját és eredményeit. A Pécsi Tudományegyetemen a pszichológusképzés indítása óta, azaz 30 éve oktatunk evolúciós tárgyakat. A bolognai képzési rendszer bevezetése óta mindhárom képzési szinten (BA, MA, PhD) vannak evolúciós kurzusok. Ebben az írásban összefoglaljuk, hogy milyen meggyőződésből és szakmai háttérből kiindulva oktatunk evolúciós kurzusokat Pécsett, és bemutatunk néhány általunk alkalmazott oktatási módszert, amely sikeresnek bizonyult az elmúlt években. Így beszélni fogunk az evolúciós vitafórumokról, a Facebook-profil-gyakorlatról és a filmrészletek elemzéséről. Összegzésként kiemeljük, hogy az evolúciós kurzusok milyen fontos szerepet töltenek be a pszichológusképzésben azáltal, hogy a hallgatók szerteágazó stúdiumainak integrálására alkalmas elméleti keretet nyújtanak.
Experimental evaluation of the influence of excessive electric current on the fire hazard of lithium-ion power cell
Authors: Lazarenko Oleksandr , Berezhanskyi Taras , Pospolitak Vitalii , Pazen Oleg
Published: September 2022

Panasonic NCR18650B (LiNi0.8Co0.15Al0.05O2) lithium-ion power cell (LIPC) and its performance after exposure to excess direct current are considered in this paper. The basic fire hazard indicators (element ignition temperature, flame temperature, element heating time, etc.) were experimentally established and mathematically confirmed for the examined LIPC.
According to the results of experimental studies, the time of occurrence of an irreversible thermochemical reaction in a lithium-ion power cell was determined depending on the different DC current strengths. Additionally, the critical temperature of the onset of an irreversible thermochemical reaction and the total combustion temperature of the element have been established. The application of the Joule-Lenz and Fourier laws allowed for a mathematical notation of the dependence (influence) of DC strength over time and the heating of the element to a critical temperature.
The heating time of Panasonic NCR18650B LIPC (LiNi0.8Co0.15Al0.05O2) to a critical temperature of 100–150 °C under the influence of excess current was experimentally established and mathematically confirmed.
The determined critical indicators of the element (temperature, time, etc.) make it possible to further devise a number of necessary regulatory documents that will allow them to be certified, tested, and, in general, to better understand the dangers that they may pose. A mathematical model was built, which, taking into account the geometrical parameters of the element, makes it possible to calculate the onset of the critical temperature of such elements with excellent geometric parameters without conducting experimental studies
Principle of the assessment of the readiness of motor transport enterprises for economic development based on a two-component methodological approach
Authors: Volynets Lyudmila , Gorobinska Iryna , Nakonechna Svitlana , Petunin Andrii , Romanyuk Svitlana , Khomenko Inna , Zachosova Nataliia
Published: September 2022

The object of this study is to assess the financial stability and readiness of motor transport enterprises for economic development. The proposed two-component methodological approach makes it possible to optimize the assessment of the readiness of enterprises for development based on the calculation of the integral indicator of investment sufficiency and the level of material cost.
The proposed methodical approach was tested, which showed the low resource capacity of enterprises. The dynamics of the integral indicator of investment sufficiency showed that, in general, for enterprises engaged in road freight transportation, its level is much lower than the standard value, which is equal to 3. Its value fluctuated on average at the level of 1.2–1.7, that is, it was in the range of lack or limited resources for economic development.
This indicates the dominance of survival strategies, not development, among motor transport enterprises, and a weak state policy that does not stimulate investment activity in a legal transparent environment. It is proposed to take into consideration the developed approach in the implementation of the state policy of supporting and stimulating enterprises that actively invest, and increase legal turnover, income, and labor reimbursement.
The obtained results can be used both at the level of individual motor transport enterprises and for aggregated assessment in the industry as a whole. An additional advantage of the developed two-component methodological approach to assessing the state and readiness of the enterprise for development is the possibility of using different components for each component, differentiating their weight in the integral assessment, and the possibility of adjusting target ranges.
Revealing the mechanism of stability loss of a two-fraction granular flow in a rotating drum
Authors: Deineka Kateryna , Naumenko Yuriy
Published: September 2022

The qualitative nature and quantitative parameters of motion instability of a two-fraction granular filler of a rotating drum were determined.
The factors of motion instability and key parameters of the oscillating system were identified and their influence on the self-excitation of pulsed self-oscillations was estimated.
Two continuous and one periodic steady-state modes of filler motion were found. Periodic self-oscillations due to the development of instability during the transition from continuous circulation mode to the wall layer mode were revealed. As factors of motion instability, filler dilatancy and damping effect of fine fraction particles on the pulsed interaction of coarse fraction particles were taken.
It turned out that the main key parameter of the oscillating system is the drum speed, which determines a change in dilatancy. The increase in instability is realized as a reduction of the bifurcation values of speed and dilatancy. Other key parameters are the content of the fine fraction in the filler κff and the filling degree of the chamber κlf, the growth of which increases the self-oscillating instability.
The features of the oscillatory system are the relaxation type, discontinuous nature of self-oscillations and hard self-excitation mode under bistability. The discontinuous character and oscillatory hysteresis increase with decreasing κff and κlf.
The limit values of the dynamic motion parameters corresponding to the conditions of self-excitation of self-oscillations in the absence and presence of fine fraction were determined: 0.96–1.11 and 0.218–0.382 for the bifurcation value of relative speed, 0.745–0.855 and 0.24–0.322 for the bifurcation value of dilatancy.
The effects found make it possible to substantiate the parameters of the self-oscillating process of processing polygranular materials in drum-type machines.
Development of a thematic and neural network model for data learning
Authors: Аkanova Akerke , Ospanova Nazira , Sharipova Saltanat , Мauina Gulalem , Abdugulova Zhanat
Published: September 2022

Research in the field of semantic text analysis begins with the study of the structure of natural language. The Kazakh language is unique in that it belongs to agglutinative languages and requires careful study. The object of this study is the text in the Kazakh language. Existing approaches to the study of the semantic analysis of text in the Kazakh language do not consider text analysis using the methods of thematic modeling and learning of neural networks. The purpose of this study is to determine the quality of a topic model based on the LDA (Latent Dirichlet Allocation) method with Gibbs sampling, through neural network learning. The LDA model can determine the semantic probability of the keywords of a single document and give them a rating score. To build a neural network, one of the widely used LSTM architectures was used, which has proven itself well in working with NLP (Natural Language Processing). As a result of learning, it is possible to see to what extent the text was trained and how the semantic analysis of the text in the Kazakh language went. The system, developed on the basis of the LDA model and neural network learning, combines the detected keywords into separate topics. In general, the experimental results showed that the use of deep neural networks gives the expected results of the quality of the LDA model in the processing of the Kazakh language. The developed model of the neural network contributes to the assessment of the accuracy of the semantics of the used text in the Kazakh language. The results obtained can be applied in systems for processing text data, for example, when checking the compliance of the topic and content of the proposed texts (abstracts, term papers, theses, and other works).
Determining the effect of the structural and technological parameters of a gas blower unit on the air flow distribution in a gas generator
Authors: Golub Gennadii , Tsyvenkova Nataliya , Golub Victor , Chuba Viacheslav , Omarov Ivan , Holubenko Anna
Published: September 2022

The object of this study is the structural and technological parameters of the gas blower unit in the gasification chamber of a gas generator. The task to enable uniform distribution of air masses in the gas generator has been solved using the ANSYS Fluent software. The study is based on a simulation of the movement of air flows in the characteristic cross-sections of the gas generator, in particular the cross-section of the gasification chamber at the border of the oxidation and reduction zones. Seven structures of the gas blower unit were analyzed, the effectiveness of which was determined by the coefficient of variation. The most effective was the design whose value of the coefficient of variation is the smallest and equal to 93 %. At the same time, the total area of zones with no movement of air masses, that is, the absence of a gasification process, does not exceed 12 % of the total cross-sectional area of the gas generator. The speed of air masses at the boundary of the oxidation and reduction zones is aligned in the entire cross-section of the chamber and is V»4.5 m/s. The average value of the vertical component of the speed of air masses in the cross-section at the inlet to the recovery zone of the gasification chamber is V»0.6 m/s. Under such conditions, the production of synthesis gas of high calorific value with the absence of resins, acids, heavy hydrocarbons, and mechanical impurities is ensured. The correspondence of the simulation results with experimental data is confirmed by the coefficient of determination, which amounted to 0.87.
The results reported here could be the basis of a modernized methodology for the study of aerodynamic, heat and mass exchange processes that occur during biomass gasification. This would make it possible to define the rational structural and technological parameters of gas generators and improve the efficiency of the gasification process as a whole.
Implementation of finite element analysis for solving the constraints in forming process of large steel parts
Authors: Kadhim Kamil Jawad , Jaber Jabbar A. , Ibrihim Hadi Raheem
Published: September 2022

In recent years, the demand for high-durability parts are rising too much. These challenges are difficult to overcome without an innovative framework based on an accurate database. The problems of high stress generated due to the hard friction and severe crystal dislocation during the forming process need to be solved. High frictional forces between the contact surfaces while forming lead to high sticking between the parts. In this work, forming process of the large sheet metal has been explored based on some parameters like material properties, stress generation, and their effects on the product quality. For this purpose, square sheet metal of 721*721*5 mm is considered, and the product formation through many forming steps was carried out. This work includes adopting some design steps, modeling, and analysis to control some parameters and minimize the generation stresses. The finite element software (ABAQUS/CAE) has been adopted for analyzing this process. In this simulation, the forming process evolution in different steps has been analyzed, and the influence of the effective parameters was performed. As a result, it’s found that the generation stresses are highly concentrated near the fillet zones and proportional to the pressure, and depend on the nature of contact and friction. Simulation results also revealed that the uniform pressure during forming will leads to minimizing the friction and stress generation (5 %) and this will improve the product quality. Also, it’s possible to identify and facilitate many difficulties and evaluate the possibilities before further investing in tooling. It’s concluded that any accurate process like this must depend on some sequence steps like design, modeling, and simulation. Moreover, folding the large surface area needs accurate and adjustable types of equipment.
Improvement of quarry and slagheap reclamation technology
Authors: Baikalov Yaroslav , Dzhygyrey Iryna , Bendiuh Vladyslav , Proskurnin Oleg , Berezenko Kateryna , Boichenko Sergii , Kryuchkov Anatoliy , Serhiienko Mykola , Danilin Oleksandr , Kutniashenko Oleksii
Published: September 2022

This paper considers and analyzes a relevant issue of treatment of disturbed soils. The equipment to carry out various processes of mining reclamation of waste heaps and quarries with a significant reduction in the level of environmental risks through the operation of an energy-saving small-sized apparatus has been designed. The use of the developed soil reclamator is also adequate for pre-sowing and other types of agrotechnical tillage, plant care in agricultural fields, as well as in areas with a heterogeneous landscape. The functionality of the unit is able to provide energy autonomy and automation of the technological process. The low weight of the device makes it possible to reduce the pressure on the soil, which minimizes the environmentally hazardous formation of dust during the treatment of waste heaps, the destruction of its structure, the machine degradation of the fertile layer during the processing of all types of territories. The device also reduces the risk of fertile soils slipping from the slopes of mine dumps due to the fact that the soil reclamator is self-propelled and functions without the need to involve a heavy tractor. The mathematical modeling of the operation of the proposed technical support for the treatment of waste heap reclamation in comparison with the opposed analog proves the ecological and economic efficiency of the eco-adaptive soil reclamator. The average value of profit ratios, when using the proposed soil reclamator, is 121.82 % higher than with the involvement of opposed equipment. Indicators of the negative environmental impact of the designed equipment are 100 % lower than the environmental impact when operating the analog. The proposed technical solution can be effectively applied both in schemes of sanitary cleaning of settlements, and in the process of modernization of agricultural machinery
Implementation of demand system restrictions and accuracy of QUAIDS model estimator on animal food demand in Indonesia
Authors: Iriany Atiek , Sui Jeky , Anindita Ratya , Khoiriyah Nikmatul , Sa’diyah Ana
Published: September 2022

Demonstration on restrictions and accuracy of an estimator is pivotal since the incomplete restrictions will make the estimator inaccurate that they cannot be used for the need of decision making. In this study, the demand system’s three primary requirements-adding up, homogeneity, and symmetry ‒ are examined. This current research was intended to demonstrate restrictions and accuracy of Quadratic Almost Ideal Demand System (QUAIDS) model estimator. The source of the data was referred to the results of National Socio-Economic Survey of Indonesia in 2016, involving 291,414 households in total. Iterated Nonlinear Seemingly Unrelated Regression method was used for the estimation procedure. Parameter estimation is used to calculate the elasticity of animal protein. The results have indicated that the three restrictions of the QUAIDS model estimator, i. e. adding up, homogeneity, and symmetry, have been completed. Further, the estimation made by the QUAIDS model is valid and efficient; therefore, the estimation is potentially used as a means of calculating own and cross price elasticity, either Marshallian or Hicksian. In addition, some other parameters, such as price, income, and income squared, are also employed to calculate income elasticity. The findings show that demand is elastic for all animal proteins, except for eggs, which are inelastic. Beef is most elastic. According to the income elasticity results, all animal proteins are considered luxury foods in Indonesia, except for eggs, which have an income elasticity of less than one. To fulfill Indonesian households’ needs for animal protein, the income policy is more suited for beef, while the price strategy is more effective for animal proteins including chicken, milk, fresh fish, and eggs
The morphological analysis of crystalline methadone: a novel combination of microscopy techniques
Authors: Al-Hasani Noor R. , Royall Paul G. , Rayment Neil , Wolff Kim
Published: September 2022

The aim: to evaluate combined microscopy techniques for determining the morphological and optical properties of methadone hydrochloride (MDN) crystals.

Materials and methods: MDN crystal formation was optimized using a closed container method and crystals were characterized using polarized light microscope (PLM), scanning electron microscopy (SEM) and confocal microscopy (CM). SEM and CM were used to determine MDN crystal thickness and study its relationship with crystal retardation colours using the Michel-Levy Birefringence approach.

Results: Dimensions (mean±SD) of diamond shaped MDN crystals were confirmed using SEM and CM. Crystals were 46.4±15.2 Vs 32.0±8.3 µm long, 28.03±8.2 Vs 20.85±5.5 µm wide, and 6.62±2.9 Vs 9.6±4.6 µm thick, respectively. There were significant differences between SEM and CM thickness measurements (U=1283, p<0.05), as the SEM exhibited thinner diamond crystals. The combined use of PLM and Michel-Levy chart enabled the observation of a predominantly yellow coloured MDN crystal, mean thickness at (428 nm) mean retardation value.

Conclusion: The SEM was superior and successfully determined MDN crystal dimensions for the first time, whilst the CM results were affected by the Rhodamine dye staining process used for visualisation. The qualitative analysis of the crystallinity status of methadone hydrochloride optimally achieved using a combination of PLM and SEM techniques
Preparation Cobalt Ferrite–Silver Nanocomposite Via Green Chemistry Approach
Authors: AKPINAR Yeliz , AVCI Begüm
Published: September 2022

Nanocomposites are formed by joining two or more materials, at least one of which must have a size in the nanometer range (1 nm -100 nm). In this study, cobalt ferrite-silver nanocomposite was prepared with a green synthesis approach. The aim was to combine the magnetic properties of cobalt-ferrite nanoparticles with both the antimicrobial and conductivity properties of silver nanoparticles. Thus, the prepared material can be used for biological, optical, electrical, and magnetic applications. Cobalt ferrite nanoparticles were prepared using the co-precipitation method. Silver nanostructures were incorporated into cobalt ferrite nanoparticles using waste grass extract. Scanning Electron Microscope (SEM), Infrared Spectrometer, UV-VIS Spectrometer, X-RAY Diffraction Spectrometer, Dynamic Light Scattering Technique were used for characterization studies.
The Affect of Aging Process on Wear Properties of Al6061/GNP Metal Matrix Composite
Authors: ASLAN Nail , TÜRKOĞLU Türker
Published: September 2022

In this study, affect of aging on wear characteristics of the nano GNP reinforced Al6061 metal matrix composites. In this scope, the samples were produced by hot press at 500 ℃ temperature under 50 MPa pressure for 30 minutes. The wear characteristics of the composites were determined using the ball-on disc wear test method. The affect of aging on the friction coefficient and wear ratio were investigated. Graphene reinforcement significantly increased the friction coefficient between the stainless steel ball and specimen but aging process lowered the coefficient of friction to a better level. Also artificially aged specimens showed significant increase in hardness values. Key factors are affecting the mechanical performance of the Al based alloy is reinforcement and aging process.
Comparison of Accelerated Exposure Tests on Organic Coatings via Electrochemical Means
Authors: TAYSUN Mehmet Bengi , GİZLİ Ali
Published: September 2022

Metal yüzeyleri korozyonun etkisinden korumak için organik kaplamalar yaygın olarak kullanılır. Organik kaplamalar ile korozyon korumasının mekanizmaları bilinmesine rağmen, bu mekanizmaların gelişiminin tuzlu sis (ASTM B-117) ve yoğuşma kabini (ASTM D4585) gibi geleneksel hızlandırılmış maruziyet testleri ile izlenmesi mümkün değildir. Bu testlerde korozyon sadece görsel emarelerin ortaya çıkmasıyla gözlenebilir, bu durum kaplama altında korozyon başlangıcından çok sonra gerçekleşebilir ve dolayısıyla numuneler arasında farkların ortaya çıkması için uzun test sürelerine ihtiyaç duyulabilir.

Bu çalışmada bir organik kaplamanın iki farklı hızlandırılmış maruziyet testi etkisi altında yıpranması takip edilmiştir. Farklı sürelerde maruziyet görmüş numunelerin elektriksel empedans spektrumlarının ölçülmesi ve uygun eşdeğer elektriksel devreler ile modellenmesi kaplama altında meydana gelen yıpranmayı göstermiştir. Görsel inceleme ile herhangi bir korozyon etkisi görülmese de, EIS ile 60 saat tuzlu sis testinde korozyon başlangıcı gözlemlenmiştir, ancak 240 saat yoğuşma kabini korozyon başlangıcı için yeterli olmamıştır. Sonuçlar test edilen kaplama sistemi için tuzlu sis testinin, yoğuşma testine göre çok daha fazla yıpranma meydana getirdiğini göstermiştir.
Power Factor Increase of Electric Drives of Railway Shunting Winches
Authors: Marenych O. L. , Karzova O. O.
Published: September 2022

Purpose. The main purpose of the work is to develop recommendations for increasing the power factor of electric drives of railway shunting winches, taking into account the peculiarities of the technological process at loading and unloading sites. To achieve this purpose, the following tasks were set: to choose a rational way to increase the power factor of the electric drive of shunting winch, taking into account the peculiarities of the technological process, simplicity and reliability of the electrical circuit; develop a methodology (calculation algorithm) to determine the elements of the circuit, which are designed to increase the power factor; conduct research to determine the numerical technical characteristics of these elements, using the developed methodology; assess the power factor increase for the electric drive of some models of winches; formulate recommendations on possible modernization of the electric drive of shunting winches. Methodology. An algorithm for calculating the reactive power of an unregulated cosine capacitor, which has to be permanently connected to the terminals of a three-phase induction motor of a shunting winch drive in order to increase the power factor, is developed. Findings. Studies have shown that the proposed method of increasing the power factor gives a significant increase in different values of the load factor of the shunting winch motor, while ensuring the simplicity of the scheme and its reliability. Originality. For the first time, taking into account the peculiarities of the technology of unloading and loading cars, a method of calculating the required reactive power of an unregulated cosine capacitor, which is connected to the terminals of the drive motor, is proposed. The formula for determining the load factor of the electric motor depending on the ratio of unloaded and loaded cars that move with a winch is proposed. The formula for determining the load factor of the electric motor depending on the ratio of unloaded and loaded cars, which move using a winch is proposed. Practical value. The results are of practical value because the obtained numerical values of increasing the power coefficients of the drives of shunting winches and reactive power required for this cosine capacitors can be used as primary information in deciding whether it is advisable to modernize winch drives by connecting to the terminals of three-phase induction motor.
Modernization of platform Schnabel car with a carrying capacity of 220 tons
Authors: Kebal I. Y , Krasnoshchok O. L
Published: September 2022

Purpose. The article is aimed to calculate the strength of the element of the special design of the Schnabel car to increase the carrying capacity up to 250 tons, as well as consider the possibility of using special cars to transport the oversized cargo according to the strength calculation results of the span bolster of the Schnabel car. Methodology. A special design of the span bolster of the Schnabel car was developed, which allowed increasing the carrying capacity of the platform Schnabel car to 250 tons. SolidWorks CAD allowed testing the span bolster strength of the modernized Schnabel car. Findings. A review analysis of railway Schnabel cars has been performed. The possibility of testing the strength of the Schnabel car design details using modern SolidWorks CAD is considered. When loading the span bolster of the modernized Schnabel car with a compressive force of 2.5 MN, the stresses do not exceed the allowable, and the design has no weaknesses. The specialists of Design and Development Technological Bureau for the Design and Modernization of Rolling Stock, Track and Artificial Structures performed research and development for the production of a sixteen-axle platform Schnabel car with a capacity of up to 250 tons. Originality. The mathematical model of the modernized sixteen-axle platform Schnabel car with a loading capacity up to 250 t was further developed. The implementation of the mathematical model in SolidWorks CAD allowed testing the design for the strength of the Schnabel car. Practical value. The results of the work can be useful for the design departments for rolling stock design and relevant specialists. Modern CAD in some way simplifies the process of designing parts and assemblies of mechanisms, allowing one to test certain system parameters with high accuracy.
Improving the Bench Testing Method of Sliding Contacts of Electric Transport
Authors: Ustymenko D. V , Diab Al Said Ahmad Mohammad Ahmad
Published: September 2022

Purpose. The work is aimed to present the results of a comprehensive study of the bench testing procedure of high-current sliding contact of electric transport, which together provide a basis for proposals, recommendations for improving the standard method of these tests. Methodology. The research is based on two classical methods of scientific research. The first one is the observation and processing of the results of a real experiment in the laboratory; the second is the development of mathematical model for determining the temperature effect in the area of sliding contact on the wear of the contact wire, with subsequent determination of the resource of this sliding contact. Findings. The result of these studies is a list of recommendations on the procedure and content of the program-methodology of bench tests of inserts of current collectors of electric transports. The obtained scientifically substantiated results will allow to assert that their introduction will reduce time, energy and other expenses for performing obligatory bench tests of new samples of current collector inserts. Originality. By means of non-destructive temperature control at the point of current collection of high-current sliding contact, taking into account the temperature limit value during current collection process, for the first time the values of the heating time constant of the «insert fragment – contact wire ring» were obtained for different insert materials. This makes it possible to predict the final result of bench tests as successful or unsuccessful already at the initial testing stage (the first 10 thousand disk passes). Based on statistical processing of experimental data, the dependences of the contact wire wear on the number of test bench passes were obtained, which creates conditions for forecasting the value of contact wire wear during bench tests relative to the reference sample. Practical value. It is experimentally proved that the dependence of the contact wire wear on the number of passes of the test bench disk is linear, which allows accelerated resource testing of high-current sliding contact elements while maintaining the adequacy of the results. In general, the comprehensive application of the received recommendations creates conditions for saving time, energy and other costs when conducting bench tests of sliding contacts of electric transport.
Research of Duration Influence of Loading and Unloading Operations on the Use Efficiency of Technological Motor Transport on Open Pit Iron Mines
Authors: Razumova K. M , Temchenko O. A. , Maksymov  S. V , Maksymova O. S.
Published: September 2022

Purpose. The most common type of technological transport in open pit mines is automobile, which uses dump trucks with a capacity of 45 to 220 tons. The rock mass transportation volume with the use of motor transport at the iron ore industry is more than 350 million tons per year, or 27% of the total volume of open pit mines in the industry. Most of Ukraine’s high-capacity iron mines are forced to work in the conditions of intensification of mining operations, constant deepening and complication of mining and geological conditions. With increasing the depth of mines there is an increase of 1.3-1.7 times the transportation volume relative to the volume of the shipped rock mass and, as a consequence, a decrease in the efficiency of technological vehicles. The purpose of this work is to analyze the influence of using BELAZ open-pit dump trucks during loading and unloading operations on the efficiency. This will allow to develop the management measures to implement effective transport technologies aimed at reducing the cost of open pit iron ore mining and purposefully influence these production processes. Methodology. In order to solve the set tasks, the methods of technical-economic, correlation-regression, factor and situational analysis were used (to study the operation of open-pit dump trucks at mining enterprises). In order to formalize the methods of improving the efficiency of equipment and transport technologies, the methodology of operational accounting of mining conditions of open-pit dump trucks operation at mining enterprises was used. To assess the economic efficiency of the proposed management system of mining activities of open-pit dump trucks, a method of comparative economic analysis was proposed. Findings. The results of the research are practically implemented in the real conditions of operation of open-pit dump trucks and the economic effect of the implementation of the proposed measures is determined. Originality. The obtained results are practically implemented in the real conditions of operation of open-pit dump trucks and the economic effect of the implementation of the proposed measures is determined. Practical value. The forms of functional connection are substantiated and analytical dependences between the indicators characterizing the use efficiency of open-pit dump trucks during the technological transportations of iron ore and the time needed for loading and unloading operations are received. This dependency allows determining the reserves for improving the operation efficiency of open-pit dump trucks and the economic effect from the implementation of the measures proposed.
TITANIUM CLIPS FOR CLOSURE OF THE PERITONEAL FLAP DURING LAPAROSCOPIC INGUINAL HERNIA REPAIR
Authors: Trindade Eduardo Neubarth , Martins Eduardo Ferreira , Trindade Manoel Roberto Maciel
Published: September 2022

ABSTRACT BACKGROUND: The laparoscopic approach for inguinal hernia repair has been widely used since its introduction in the 1990s. As a step in the procedure, the surgeon must access the preperitoneal space through an incision in the peritoneum, creating an adequate dissection for mesh placement. At the end of the procedure, the peritoneal flap must be closed to avoid adhesions. There are several methods to close the peritoneum. AIMS: The aim of this study was to propose a simple method for closing the peritoneal flap, using titanium clips, exposing its advantages and disadvantages. METHODS: Description of the peritoneum flap closure technique, using titanium clips, in the last 15 years. RESULTS: The pneumoperitoneum was reduced to a pressure of 7 mmHg; then, the two edges of the peritoneal flap were approximated together and, with the aid of a Maryland grasper, were kept together; titanium clips were used to close the flap. The process is repeated along the entire peritoneal incision until it is completely closed. CONCLUSIONS: The use of titanium clips proved to be a fast, inexpensive, and effective method for closing the peritoneal flap in videolaparoscopic inguinal hernioplasties, with no major or recurrent complications reported. Therefore, it is an effective and safe method for the closure of the peritoneal defect.
Physical attributes and yield of wheat seeds originated from plants under temporary flooding of the soil
Authors: Monteiro Manoela Andrade , Koch Felipe , Araújo Bruno Oliveira Novais , Uliana Adriel Somavilla , Rolim Jessica Mengue , Altmann Thomas , Martinazzo Emanuela Garbin , Pedó Tiago , Aumonde Tiago Zanatta
Published: September 2022

ABSTRACT: The aim of this work was to evaluate whether there is any influence of temporary soil flooding on the agronomic performance and yield of wheat varieties. The experimental design was completely random blocks, in an 11x2 factorial scheme (eleven varieties and two soil water conditions), with four replications. Stress was imposed in the stage prior to plant anthesis. The assessments were made in two seasons (2016/2017) in relation to the number of spikelets in the main ear, number of seeds in the main ear, mass of seeds in the main ear, number of seeds in the tiller ear, mass of seeds in the tiller ear and yield in the useful area. The physical attributes number of seeds, seed mass and wheat seed yield, according to variety and agricultural year, are negatively affected by the temporary flooding (12 days) of the soil. There is influence of temporary soil flooding on the agronomic performance and yield of wheat varieties. The varieties TBio Toruk, TBio Sinuelo, TBio Sintonia, and CD151 are superior in soil flooding condition for the number of spikelets, number of seeds end for the seed mass attribute. In the soil at field capacity, the seeds produced have higher yield compared to those produced under flooding period, reaching about 309.2 Kg more for the variety TBio Sinuelo, 262 Kg for TBio Toruk and 114 Kg in CD1303.
Por que são convocadas as Audiências Públicas no Supremo Tribunal Federal?
Authors: Marona Marjorie , Magalhães Lucas Fernandes de , Araújo Mateus Morais
Published: September 2022

RESUMO Introdução: As audiências públicas (AP) no Supremo Tribunal Federal (STF) foram previstas pela legislação brasileira desde 1999, mas a primeira delas ocorreu apenas em 2007. Das centenas de ações anualmente distribuídas no STF, não mais do que duas vão contar, ao longo de seu processamento, com a realização de uma AP. São eventos raros. Mas por que são convocadas? Materiais e Métodos: A pesquisa procura responder a essa questão. A partir de uma base de dados contendo ações de controle concentrado distribuídas entre 1988 e 2020, foram testadas empiricamente duas hipóteses: as chances de convocação de uma AP aumentam (1) quanto maior a saliência da causa em questão e (2) quando existe divergência entre os ministros do Tribunal. Resultados: As balizas legais que regulam a convocação da audiência pública no STF são bastante vagas e a literatura, até o momento, não se desimcumbiu da função de explicar porque algumas ações contam com audiência e outras não. O presente artigo inova e contribui para a agenda ao identificar alguns padrões envolvendo o chamamento de audiências no STF. Os dados levantados mostram que quanto maior o número de petições de amici curiae protocoladas em uma ação e de notícias publicadas sobre ela (medidas usadas como proxy da repercussão social), maiores as chances de o Relator convocar uma audiência pública. Também foi identificado que ações com julgamentos majoritários (isto é, nos quais há pelo menos uma divergência) possuem mais chances de contar com uma audiência pública em relação àquelas ações com decisões unânimes. Discussão: Os resultados encontrados corroboram ambas as hipóteses levantadas pelo artigo. Os ministros parecem estar atentos à repercussão social dos casos sob julgamento, vislumbrando nas audiências uma oportunidade de comunicação com o público e uma janela para, talvez, ampliar o apoio difuso à corte. Ademais, a convocação da AP parece servir como mecanismo para reduzir as chances de derrota do relator quando há divergência entre os ministros, seja como um análogo do controle de agenda, seja como uma fonte de argumentos de autoridade que reforçam e tornam o voto mais persuasivo perante os pares. Em outras palavras, fatores exógenos (repercussão social) e endógenos (divergência interna) parecem influenciar a decisão dos ministros pela convocação das audiências.
Scheduling for Additive Manufacturing: a literature review
Authors: Dall’Agnol Gabriela , Sagawa Juliana Keiko , Tavares Neto Roberto Fernandes
Published: September 2022

Abstract: Advancements in production technologies and materials have facilitated the use of additive manufacturing (AM) (i.e., 3D printing) in the large-scale production of finished products with high level of customization, simplification of the factory floor, and fast delivery. Production sequencing is a well-established topic in this research area; however, its application to an AM environment suffers from specific issues that are yet to be explored. This paper presents a systematic literature review for mapping the state-of-the-art production sequencing methods in AM and for discussing the content of 26 articles published in magazines between 2017–2020. The main mathematical models, algorithms adopted for their solution, and main characteristics of computational experiments performed in these articles are identified; the results indicate that some characteristics of the problem can still be included in these models, such as the possibility of outsourcing and technology restrictions, which are yet to be explored in the literature. Further, authors observed the need for more robust computational experiments to better evaluate the proposed solutions.
Characterization of dystocia in a herd of Holstein dairy cows in Brazil
Authors: Lourenço Jean Carlos Steinmacher , Ossani Paulo Cesar , Salles Márcia Saladini Viera , Bánkuti Ferenc Istvan , Almeida Rodrigo de , Rossoni Diogo Francisco , Osorio Jesús Alberto Cardozo de , Santos Geraldo Tadeu dos
Published: September 2022

Abstract The objective of this study was to characterize calvings with low and high difficulty based on the productive and reproductive performance of dairy cows. Calvings were grouped in no calving assistance, calving with low assistance, and calving with high assistance. The original data set comprised 1,902 calving records obtained from a large dairy farm in Southeast Brazil. Factor analysis was applied using the SAS® Studio 3.8 statistical program through the factor procedure, considering the Multivariate Analysis category. Milk fat (0.92–0.79) and total solids (0.91–0.80) were strongly correlated with Factor 1. Calving interval (0.87– 0.68) and the number of AI (artificial inseminations) per conception (0.87–0.71) showed high correlations with Factor 2. Milk yield (0.84–0.76) and accumulated milk yield (0.84–0.77) were strongly correlated with Factor 3. Based on the results, we conclude that the three calving scenarios were characterized by well-defined and independent factors. Cows which required a high assistance at calving showed a lower variance explained by the model for milk fat and total solids contents, calving interval, and the number of AIs per conception.