bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diseño y administración de proyectos de robótica educativa: lecciones aprendidas
Authors: Acuña Zuñiga Ana Lourdes 
Published: July 2021

El inicio de proyectos educativos que incluyen la robótica como recurso de enseñanza y aprendizaje requieren plantearse en función de las capacidades y desempeños que se esperan consolidar en la población meta. Estas capacidades son el punto de partida para delinear los énfasis de contenido, los desempeños deseados, las tecnologías que se necesitan, los procesos de capacitación y seguimiento que hay que diseñar. La robótica educativa es propicia para apoyar habilidades productivas, creativas, digitales y comunicativas; y se convierte en un motor para la innovación cuando produce cambios en las personas, en las ideas y actitudes, en las relaciones, modos de actual y pensar de los estudiantes y los educadores. Si esos cambios son visibles en la práctica cotidiana, entonces estamos ante una innovación porque la robótica habrá transcendido sus intuiciones y se reflejara en sus acciones y productos.
Diseño funcional y propuesta de implementación de una herramienta de apoyo a la construcción colaborativa de conocimiento
Authors: Garcia Gonzalez Iolanda 
Published: July 2021

Este artículo describe el proceso de conceptualización y diseño funcional de un foro electrónico, que se propone facilitar aquellos procesos de aprendizaje que toman como base la comunicación, pero también la colaboración y la construcción de conocimiento, así como su seguimiento y evaluación. La experiencia se basa en un proyecto de innovación que implicó el diseño, el desarrollo y la implementación piloto de esta herramienta de comunicación asíncrona, en el contexto del campus virtual de la Universitat Oberta de Catalunya (UOC). El diseño de la herramienta parte del análisis de distintos modelos de referencia en lo que respecta al apoyo tecnológico de procesos de aprendizaje colaborativo y de construcción social de conocimiento. En paralelo, y tras analizar algunos modelos para el estudio de la construcción colaborativa de conocimiento en entornos virtuales, se presenta una propuesta de análisis y evaluación de este tipo de procesos mediados por herramientas de comunicación asíncrona similares a la diseñada.
Fracture Resistance of Anterior CAD/CAM Nanoceramic Resin Endocrowns with Different Preparation Designs
Authors: Badr Aly Abdelkawy , Abozaid Amira Ahmed , Wahsh Marwa Mohamed , Morsi Tarek Salah 
Published: July 2021

Objective: The aim of the study was to evaluate the effect of extension of endocrown in pulp space and the effect of ferrule on the fracture resistance of anterior endocrowns made of nano-ceramic resin blocks. Material and Methods: Twenty-eight freshly extracted human upper central incisor teeth were prepared to receive CAD/CAM nanoceramic resin endocrowns with four different designs. The specimens were divided into two groups (n = 14) according to the extension of the endocrown inside root canal (A:short and B:long), then each group was further subdivided into another two subgroups (n = 7) according to the presence or absence of ferrule effect (1:ferrule and 2: no ferrule). Endocrowns were then fabricated using CEREC in lab and nanoceramic resin blocks (DENTSPLY Sirona, Germany) and LAVA ultimate (3M ESPE, Germany) blocks size 14L. Results: Two-way ANOVA showed that the ferrule (P > 0.0001) had statistically significant effect on the fracture resistance. However, the extension of the endocrown into the canal had no statistical significant effect on the fracture resistance (P = 0.837). The interactions between the independent variables (extension into the canal and ferrule) had statistically significant effect on the fracture resistance(P = 0.029). Load to fracture for group 1A was 439.53 N, 1B was 306.46 N, 2A was 516.29 N and 2B was 242.04 N. Conclusions: Fracture resistance was not improved by the long or short extensions of the endocrowns in the pulp space, however, the ferrule effect shows significant improvement of the fracture resistance of the nanoceramic resin endocrowns.

Keywords
Anterior endocrowns; Endocrown extensions; Fracture resistance; Nanoceramic resin blocks.
Influence of Preparation Design, Restorative Material and Load Direction on The Stress Distribution of Ceramic Veneer in Upper Central Incisor
Authors: Meirelles Laura Célia Fernandes , Pierre Fernanda Zapater , Tribst João Paulo Mendes , Pagani Clovis , Bresciani Eduardo , Borges Alexandre Luiz Souto 
Published: July 2021

Objective: Evaluate the effect of four preparation designs, two ceramic materials, and two occlusion contact types on the stress distribution of ceramic veneer in upper central incisor. Material and methods: 3D-models were performed in the modeling software containing enamel, dentin, pulp, periodontal ligament and a base of polyurethane resin. The designs were modeled and exported to the computer aided engineering software to perform the static structural analysis. For the mesh, a total of 155429 tetrahedron elements and 271683 nodes were used, after a 10% convergence test. Two materials, lithium disilicate and feldspathic ceramics, were simulated. A static load of 100 N on 45º was applied on the incisal and middle thirds of the palatal tooth region, guided by the occlusal plane. The base was constrained in all directions. The Maximum Principal Stress was the failure criteria chosen for the analysis. Results: The Finite Element Analysis showed that the most conservative designs presented less stress concentration on the ceramic veneer. However, the highest tensile stress concentrations were observed on lithium disilicate veneer with extend design, on the middle third. The type of occlusal contact presented different stress patterns among the preparation designs; the incisal contact showed higher stress concentration compared to middle third contact regardless the ceramic material. Conclusions: To perform a ceramic veneer in upper central incisor, the feldspathic ceramic presented promising results and should be recommended when the extended design was done. Regarding contact types, the incisal contact is more prone to failure regardless the ceramic and preparation design.

Keywords
Ceramics; Dental veneers; Finite element analysis.
Cone Beam Computed Tomography Based Sex Estimation by Volume of Odontoid Process of The Second Cervical Vertebra
Authors: Costa André Luiz Ferreira , Barbieri Ana Amelia , Costa Gonçalves Bianca , Felisbino Silva Camila , Massahiro Ogawa Celso , De Almeida Baldini Cardoso Cristiane , Castilho Fardim Karolina Aparecida , Pereira de Castro Lopes Sérgio Lucio 
Published: July 2021

Objective: The aim of this study was to evaluate whether the volume of odontoid process of the second cervical vertebra on CBCT images can be used for sex estimation. Material and Methods: The volume of odontoid process on CBCT images of 138 subjects was measured. In addition, the patients were classified into five age groups. The comparisons between the groups in relation to sex and age were performed by using Mann-Whitney’s test and Kruskal-Wallis’ test, respectively. The ROC curve was used to assess the sensitivity and specificity of the volume to determine the sex. Results: No statistically significant difference was observed between age and volume. Males had significantly larger volumes than females. Values of volume equal to or greater than 1.254 mm3 have sensitivity of 68.2% and specificity of 68.1% to determine male sex. Conclusion: The volume of the odontoid process tends to be larger in males than in females and can be used as sex estimation.
KEYWORDS
Cone beam computed tomography; Diagnostic imaging; Sex determination processes; Image processing; Computer-assisted.
The ability of platelet-rich plasma to regenerate a non-vital immature permanent teeth
Authors: Abdo Salma , Alkaisi Amera 
Published: July 2021

Objectives: To test the ability of platelet-rich plasma clinically and radiologically for pulp regeneration of immature teeth with apical periodontitis. Material and Methods: An experimental study was conducted From (March/2018-July/2020) 12 upper central immature incisors with acute apical periodontitis and necrotic pulp from six patients receiving regenerative endodontic treatment using concentrated platelets rich plasma were performed by the same endodontist at Mediclinic Middle East Hospitals. Informed consent, including explanation of risks and alternative treatments or no treatment were prepared and filled by the patient parents. The therapeutic protocol was involved accessing the pulp chamber; irrigation copiously with sodium hypochlorite; applying calcium hydroxide as intracanal medicament and a provisionally sealing it after 4 weeks. The canal was cleaned, dried and injected with concentrated platelets rich plasma which serve as a scaffold for pulp regeneration. MTA was used to seal the chamber before final filling with composite. Evaluations: All teeth were monitored clinically (mobility, palpation, percussion, and sensitivity cold test) and radiographically. Results: Twenty months follow-up all teeth showed resolution of periapical radiolucencies, continued root development with positive response to sensitivity cold test and no discoloration. Conclusion: The results of this study confirmed the previous finding that pulp regeneration can be gained by using cPRP successfully

Keywords
Immature teeth; Necrosis; cPRP; Regeneration.
The Judgment as Revelation
Authors: Kunc François 
Published: July 2021

Abstract
The judge’s judgment is intended to be the definitive means of quelling controversy – the last word. While judgments have always been open to question by various means, the current social and political environment is especially prone to challenging the judgments of courts. This paper will consider the judgment through the lens of ideas about text, truth and legitimacy to explore the pressure such challenges can place on the capacity of law to hold the line in times of uncertainty.
Emissivity measurements on reflective insulation materials
Authors: Adibekyan Albert , Kononogova Elena , Hameury Jacques , Lauenstein Marcus , Monte Christian , Hollandt Jörg 
Published: July 2021

Abstract
The development and use of new thermal insulation products in many industrial sectors, ranging from building insulations to power generation or satellite applications, requires the accurate knowledge of the radiative properties of the investigated material, i. e. its emissivity. A major objective of the research project “Improvement of emissivity measurements on reflective insulation materials” within the framework of the European Metrology Programme for Innovation and Research was to improve and validate reference techniques for the measurement of the total hemispherical emissivity of low emissivity foils with an absolute measurement uncertainty below 0.03. The calibration and measurement procedures developed within this project shall lead to a significant benefit for industrial manufacturers of reflective foils as well as for the end-users of the industrial instruments used to characterize them.
Gestational Age at Term and Educational Outcomes at Age Nine
Authors: Hedges Amanda , Corman Hope , Noonan Kelly , Reichman Nancy E. 
Published: July 2021

OBJECTIVES
To estimate associations between gestational age (GA) and teacher-reported academic outcomes at age 9 years among children born at term (37–41 weeks).

METHODS
A secondary data analysis of 1405 children participating in a national US birth cohort study was conducted. At age 9 years, students were evaluated by their teachers in the areas of mathematics, science and social studies, and language and literacy. Unadjusted and adjusted logistic regression models of associations between GA and teacher-reported academic outcomes were estimated and neonatal morbidities were explored as potential pathways.

RESULTS
A continuous measure of GA in weeks was significantly associated with above-average rankings in all areas. The associations were similar across outcomes (eg, mathematics [odds ratio (OR): 1.13; confidence interval (CI): 1.02–1.25], science and social studies [OR: 1.13; CI: 1.01–1.26], and language and literacy [OR: 1.16; CI: 1.05–1.28]) in a model that adjusted for child sex, maternal characteristics, and obstetric risk factors and delivery complications. Other specifications indicate a positive association between late term (41 weeks) and mathematics and a negative association between early term (37–38 weeks) and language and literacy, compared with term (39–40). The associations did not appear to operate through neonatal morbidity.

CONCLUSIONS
The findings highlight the importance of GA, even at term. Whereas current guidelines suggest waiting until at least 39 weeks to deliver when possible, our findings add to a small group of studies suggesting that GA through 41 weeks is associated with improvements in some educational outcomes.
The use of mica schist from Indonesia as raw material for lithium extraction process using sulfate roasting and acid leaching
Authors: Natasha Nadia Chrisayu , Lalasari Latifa Hanum , Andriyah Lia , Arini Tri , Yunita Fariza , Haryono Didied , Rinanda Fani 
Published: July 2021

Lithium minerals become a sub-economic raw material for lithium production to fulfill the lithium demand. This study is about lithium extraction from mica schist using the roasting and leaching processes. The mica schist located in Kebumen, Indonesia was used to study the phenomena during the lithium extraction process. Sodium sulfate was used as a roasting agent while 0.36 M sulfuric acid was used as a leaching agent. Solid/liquid ratio (1:5, 1:10, 1:15 and 1:20 (g/mL)) and leaching time (30, 60, 90 and 120 minutes) were used as variables in this study. The roasting process was done at 700 °С for 40 minutes while the leaching process was done at 70 °С and 350 rpm. The ratio of additive and mica schist was 1.5:1 (g/g). XRD, ICP-OES, and SEM were used to observe the formed compounds, chemical composition and morphology of the materials. HighScore Plus (HSP) was used to interpret the content of each compound in mica schist, roasted mica schist, and residue. ICP analysis confirmed that the mica schist contains 45.28 ppm of lithium. It is supported by XRD that lithium exists in mica schist as lepidolite (KLi2AlSi4O10(F,OH)2). Sulfate roasting did not affect the type of lepidolite but the lepidolite reactivity against the chemical agent. SEM analysis shows that the roasting process reduced the average particle size from 32.17 to 27.16 µm. ICP analysis of roasted mica schist shows that lithium concentration was reduced from 45.28 to 1.27 ppm. The optimum result from this study was 97.66 % extraction of lithium while solid/liquid ratio was 1:5 (g/ml) and leaching time was 30 minutes. HSP shows that lepidolite contents in initial mica schist, roasted mica schist and residue were 60.6; 24.3 and 18.7 %, respectively. Lithium concentration in the residue according to ICP analysis is 1.06 ppm.
Justifying the prolongation of the service life of the bearing structure of a tank car when using Y25 bogies
Authors: Fomin Oleksij , Lovska Alyona , Ivanchenko Kseniia , Medvediev Ievgen 
Published: July 2021

This paper substantiates the use of Y25 bogies under tank cars in order to prolong their service life. The reported study has been carried out for a tank car with rated parameters, as well as the actual ones, registered during full-scale research. Mathematical modeling was performed to determine the basic indicators of the tank car dynamics. The differential equations of motion were solved by a Runge-Kutta method using the Mathcad software package (USA). It was established that the use of Y25 bogies under a tank car with rated parameters could reduce the acceleration of its bearing structure by almost 39 % compared to the use of standard 18‒100 bogies.
Applying the Y25 bogies under a tank car with the actual parameters reduces the acceleration of its load-bearing structure by almost 50 % compared to the use of standard 18‒100 bogies.
The derived acceleration values were taken into consideration when calculating the bearing structure of a tank car for strength. The calculation was performed using the SolidWorks Simulation software package (France). The resulting stress values are 18 % lower than the stresses acting on the load-bearing structure of a tank car equipped with 18‒100 bogies.
For the load-bearing structure of a tank car with the actual parameters, the maximum equivalent stresses are 16 % lower than the stresses when the 18‒100 bogies are used.
The design service life of the load-bearing structure of a tank car was estimated taking into consideration the use of Y25 bogies. The calculations showed that the design service life of the bearing structure of a tank car equipped with Y25 bogies is more than twice as high as that obtained for 18‒100 bogies.
The study reported here would contribute to compiling recommendations for prolonging the service life of the load-bearing structures of tank cars
Determining the width of a layer cut with saws with multidirectional teeth
Authors: Okhrimenko Oleksandr , Vovk Vyacheslav , Maidaniuk Serhii , Lashyna Yuliia 
Published: July 2021

To predict the workability of a tool structure at the design stage, it is necessary to calculate the parameters of the cut layer when this tool is used because the cut layer’s size determines the strength and dynamic characteristics of the cutting process.
It is known that the size and shape of the cut layer are affected by the allowance cutting scheme embedded in the tool design. Therefore, the parameters of the cut layer with the tool must be investigated taking into consideration the actual shapes and location of the cutting edges of the tool teeth and the cutting scheme with individual teeth.
Existing analytical dependences on determining the thickness of the cut layer do not take into consideration the group arrangement of the teeth, which have a different shape and location of their cutting edges. Therefore, a procedure for determining the thickness of the cut layer analytically has been proposed, using the example of circular saws with multidirectional teeth while taking into consideration the patterns in the arrangement of the cutting edges of individual teeth and the real movements of the tool during its operation.
The proposed procedure makes it possible to determine the parameters of the layer cut with the tool at both constant and progressive allowance cutting schemes. One can also specify the parameters of the cut layer at any time of the tool’s operation and analyze the change in the shape of the slice in time.
Based on the analysis of the parameters of the cut layer, it has been established that saws with multidirectional teeth do not work with the entire width of the cutting edge but only in its part, whose share does not exceed 55 % of the width of the tool.
The procedure reported here could be used to determine the loading of the cutting tool part with a more complex cutting scheme, which also includes tools that are operated by the form-generating method
Identifying changes in the technical parameters of milking rubber under industrial conditions to elucidate their effect on the milking process
Authors: Paliy Andriy , Aliiev Elchyn , Nanka Alexander , Bogomolov Oleksiy , Bredixin Vadim , Paliy Anatoliy , Shkromada Oksana , Musiienko Yurii , Stockiy Aleksandr , Grebenik Natalia 
Published: July 2021

Many years of experience in the operation of milking machines show that milking rubber was and remains a short-lived and unreliable link in the technological process of machine milking. During operation, rubber quickly loses its strength and elastic properties, becomes stiff and less elastic, deforms, and changes its shape.
The purpose of this study is to identify changes in the technical parameters of milking rubber under industrial conditions in order to establish their impact on the milking process. The obtained results could make it possible to rationally choose the milking rubber for teat cups, which would ensure an effective milking process.
During this study’s initial stage, the physical and mechanical condition of milking rubber was experimentally established at steam disinfection and as a result of saturating the article with milk fats. The following stage implied detecting the effect of milking rubber tension in a teat cup on the speed of milking.
It was established that milking rubber during operation is actively exposed to milk fat, which leads to the loss of its weight relative to its original value. On day 1,000 of work, the weight loss relative to the initial value (100 g), under the washing regime temperature of 85 °C, 50 °C, 35 °C, and 20 °C, was 1 g, 3.3 g, 5 g, and 4.2 g, respectively. The dependences have been derived for the swell mass of milking rubber M on the temperature of washing solutions T and the duration of operation t as a result of saturation with milk fats.
The dependence of milk yield rate V on the tension force of milking rubber F in teat cups has been established. Thus, it was found that when the tension force of milking rubber changes from 25 to 60 N, the difference in the average intensity of milk yield is 0.13 kg/min (10.8 %). Regarding the amount of milk yield at the specified tension, the difference is 0.15 kg (2.5 %). At rubber tension from 60 to 25 N, the average milking time increases by 0.46 min (8.3 %). Thus, it was determined that a milking machine with milking rubber at different tension over a total milking time would unevenly milk different parts of the cow’s udder.
The study reported here expands the idea about the technical and manufacturing characteristics of rubber articles, namely changes in them at steam disinfection and as a result of saturation with milk fats
Determining the loose medium movement parameters in a centrifugal continuous mixer using a discrete element method
Authors: Statsenko Volodymyr , Burmistenkov Oleksandr , Bila Tetiana , Demishonkova Svitlana 
Published: July 2021

The processes to form the compositions of loose materials in centrifugal mixers of continuous action have been considered. Based on the method of discrete elements, a mathematical model of the movement of particles in the rotor of the centrifugal mixer was built, taking into consideration their geometric and physical-mechanical parameters. To assess the extent of influence of these parameters on the nature of particle movement, a well-known mathematical model in the form of a system of differential equations was used, which was built on the basis of classical laws of mechanics. The process of mixing particles of two loose materials under different initial conditions of movement was modeled. The trajectories of individual particles along the bottom and side wall of the rotor were calculated.
The results of the research reported here have established that the model built on the basis of the discrete element method makes it possible to improve the accuracy of determining the parameters of the movement of loose materials in the mixing zone. Calculations that involved this method show that the length of the particle trajectory is 2.9, and the movement time is 9 times greater than those calculated by the system of differential equations. The built and known mathematical models demonstrated the same nature of the distribution of components in the mixer. The value of the Pearson correlation coefficient between the calculated values of the coefficients of variation is 0.758. The best homogeneity is achieved by separating the flows of the mixture components and reducing the distance between their centers.
The experimental study was carried out using a centrifugal mixer of continuous action with a conical rotor. Particle trajectories were constructed; it was established that the shape of the trajectory built by a discrete element method is closer to the experimental one.
The results reported in this paper make it possible to predict the impact of the structural and technological parameters of the mixers of continuous action on the uniformity of the mixture