bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual and Tomographic Outcomes of a 300° Arc-length ICRS Implantation in Moderate to Advanced Central Keratoconus
Authors: Alfonso José F. , Torquetti Leonardo , Fernández-Vega-Cueto Luis , Allan Bruce , Poo-López Aranzazu , Alfonso-Bartolozzi Belén , de la Cruz José , Monteiro Tiago , Madrid-Costa David
Published: April 2021

PURPOSE:

To assess the outcomes of implanting a new 300° arc-length intrastromal corneal ring segment (ICRS) in moderate to advanced central hyperprolate keratoconus.

METHODS:

Forty-two eyes with moderate to advanced central hyperprolate keratoconus were evaluated before and after implanting an inferior 300° ICRS (AJL Ophthalmic). The clinical measurements taken included manifest refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuity (logMAR scale), and corneal tomographic analysis (Sirius; Costruzioni Strumenti Oftalmici). Changes in the anterior and posterior corneal surfaces and the root mean square (RMS) for coma-like aberrations for a pupil size of 4.5 mm were evaluated. All examinations were performed before surgery and 6 months after surgery.

RESULTS:

The mean UDVA improved from 1.12 ± 0.48 logMAR preoperatively to 0.73 ± 0.37 logMAR postoperatively (
P
< .0001). The mean CDVA changed from 0.33 ± 0.20 to 0.20 ± 0.11 logMAR (
P
< .0001). Postoperatively, the CDVA improved by two or more lines in 45.2% of the eyes and increased by one line in 19.04%, and none of the patients lost lines of CDVA. All of the anterior and posterior corneal tomographic parameters analyzed were significantly improved after surgery, except posterior flat keratometry, which remained unchanged. In 80.95% of the eyes, the postoperative mean keratometry was 50.00 diopters or less. The 6-month RMS for coma-like aberrations also declined significantly from 1.57 ± 0.68 to 1.06 ± 0.42 µm after surgery (
P
< .0001).

CONCLUSIONS:

These results suggest that implanting a 300° arc-length ICRS is a safe and effective procedure for treating patients with moderate to advanced central hyperprolate keratoconus and clear cornea.

[
J Refract Surg
. 2021;37(4):249–255.]
Lactose Intolerance in Pediatric Patients and Common Misunderstandings About Cow's Milk Allergy
Authors: Di Costanzo Margherita , Biasucci Giacomo , Maddalena Ylenia , Di Scala Carmen , De Caro Carmen , Calignano Antonio , Canani Roberto Berni
Published: April 2021

Lactose intolerance is a common gastrointestinal condition caused by the inability to digest and absorb dietary lactose. Primary lactose intolerance is the most common type of lactose intolerance. It is one of the most common forms of food intolerance and occurs when lactase activity is reduced in the brush border of the small bowel mucosa. People may be lactose intolerant to varying degrees, depending on the severity of these symptoms. When lactose is not digested, it is fermented by gut microbiota, leading to abdominal pain, bloating, flatulence, and diarrhea with a considerable intraindividual and interindividual variability in the severity of clinical manifestations. These gastrointestinal symptoms are similar to cow's milk allergy and could be wrongly labeled as symptoms of “milk allergy.” There are important differences between lactose intolerance and cow's milk allergy. Therefore, a better knowledge of these differences could limit misunderstandings in the diagnostic approach and in the management of these conditions.

[
Pediatr Ann
. 2021;50(4):e178–e185.]
Pediatric Facility Recognition Program and the Illinois EMSC Experience
Authors: Dolan Patrick , Nozicka Charles , O'Brien Cassandra R.
Published: April 2021

Emergency medical services (EMS) systems were initially developed in the United States during the late 1960s. Modeled from military experiences, EMS demonstrated that survival for prehospital patients could be improved with enhanced field triage, treatment, and transport protocols. Over the next few decades, it was identified that children and adolescents had poorer outcomes in similar acute medical situations as compared to adults. To address this, the emergency medical services for children (EMSC) program was established in 1985 as a federal initiative to ensure appropriate resources and adequately trained personnel are available to meet the emergency care needs of children who are critically ill and injured. In 1994, the Illinois EMSC program was established and a pediatric facility recognition program to improve the emergency care of pediatric patients was rolled out in 1998. This article reviews the development of EMSC facility recognition programs and discusses their unique characteristics and contributions to improved pediatric emergency care.

[
Pediatr Ann
. 2021;50(4):e165–e171.]
Iglesia San José, San Juan, Puerto Rico: perspectiva arqueológica a cinco siglos de su historia constructiva
Authors: Rodríguez López Jorge A. , Rivera Groennou Juan M.
Published: April 2021

La investigación de Arqueología de la Arquitectura en la Iglesia San José, San Juan de Puerto Rico, se enmarcó en el proyecto de restauración que lleva a cabo actualmente el Patronato de Monumentos de San Juan Inc. Dicha investigación se enfocó en analizar el desarrollo de las diferentes técnicas y materiales constructivos asociados al s. XVI: ábside, crucero y transepto. Entre sus objetivos estuvieron: aportar información sobre las técnicas y materiales constructivos utilizados; aportar criterios científicos que permitieran identificar la extensión y límites de cada una de sus fases y etapas constructivas. Los resultados permitieron la identificación de diversas técnicas constructivas utilizadas, así como una delimitación precisa de su configuración a lo largo de sus casi 500 años. Estos resultados presentan una perspectiva mucho más dinámica sobre los procesos constructivos del inmueble y confirman la necesidad de estudios arqueológicos en obras de restauración de edificios patrimoniales.
Élites, médias et « opinion publique » : la Hongrie du début du XVIIIe siècle jusqu’à l’ère des Réformes
Authors: Aubert Mathieu
Published: April 2021

L’article traite de l’adéquation du modèle théorique établi par Jürgen Habermas au sujet de l’émergence d’une sphère publique autonome avec les réalités politiques et sociales hongroises des XVIIIe et XIXe siècles. Si certains concepts du philosophe allemand semblent pertinents (diffusion des moyens techniques, dissociation des modèles décisionniste et délibératif pour la prise de décision politique, élargissement des groupes sociaux concernés par cette dernière), l’application du modèle dans son ensemble paraît plus incertaine. Ainsi, les subtilités du système politique hongrois, caractérisé par l’importance d’assemblées délibératives plus ou moins contraintes par le pouvoir viennois, s’accommodent mal de la généalogie du modèle habermassien. Par ailleurs, le rôle déterminant des élites nobiliaires traditionnelles dans les évolutions de la première moitié du XIXe siècle remet en cause l’affirmation d’une élite médiatique indépendante des élites politiques, condition censément indispensable pour l’émergence de l’opinion publique habermassienne.
La presse contre les élites ? Le cas de Charlie Hebdo dans les années 1970
Authors: Mazurier Stéphane
Published: April 2021

Journal emblématique des « années 68 », Charlie Hebdo a notamment exercé sa verve satirique envers certaines élites de la société française : les industriels, les magnats de la presse, mais surtout les responsables politiques de la droite gaullo-giscardienne. Ce discours anti-élitaire ne dévie cependant pas vers le populisme, ni même l’ouvriérisme. Les membres de la rédaction sont majoritairement issus des classes populaires, et portent un regard très distancié sur les élites intellectuelles classiques. En revanche, ils s’inscrivent parfaitement dans la « contre-culture » des années soixante-dix et s’agrègent ainsi à une espèce de « contre-élite ». Enfin, la victoire de la gauche en 1981 a pour effet de placer Charlie Hebdo dans une position délicate de soutien aux nouvelles élites politiques au pouvoir.
Mathematical modeling and effect of thin-layer drying and lyophilization on antioxidant compounds from ultrasonic-assisted extracted Muntingia calabura peels
Authors: Tavone Luciana Alves da Silva , Nascimento Kauyse Matos , Fachina Yasmin Jaqueline , Madrona Grasiele Scaramal , Bergamasco Rita de Cássia , Scapim Mônica Regina da Silva
Published: April 2021

Muntingia calabura fruits are rich in bioactive compounds such as antioxidants, and the consumption of these compounds is associated with cancer prevention and aging. In this study, mathematical models were used to fit the experimental data of the Muntingia calabura peel drying kinetics, and the effective diffusion coefficient, activation energy and thermodynamic properties of the process were determined. Then, the effect of the drying temperature on the antioxidant activity and phenolic compounds of fruit peels was examined using conventional extraction and ultrasonication. Among the analyzed models, the logarithmic model was selected to represent the drying phenomenon of the calabura peel kinetics. The effective diffusion coefficient decreased by 74% as the temperature increased from 40 to 60°C, and the activation energy for liquid diffusion during drying was 23.96 kJ mol-1. The enthalpy and entropy decreased with increasing temperature, while the Gibbs free energy increased by 5% for each 10°C increase in temperature. Regarding the content of phenolic compounds and the antioxidant activity of the calabura peel, it was observed that an increase in the drying temperature had a positive effect on the conservation of the bioactive compounds, making it possible to conclude that drying at 60°C and ultrasound extraction are the most suitable approach to conduct the process.
Technology 4.0 with 0.0 costs: fuzzy model of lettuce productivity with magnetized water
Authors: Matulovic Mariana , Putti Fernando Ferrari , Cremasco Camila Pires , Gabriel Filho Luis Roberto Almeida
Published: April 2021

In agriculture with 4.0 technologies, developing a decision model with a 0.0 cost is attractive to small farmers. In water management, if this approach could be used to promote sustainability and optimization, it could become a pathway to reach the sustainable development goal in 2030. The core of this work is the development of a 4.0 mathematical model (based on fuzzy concepts) to verify the benefits of the production of lettuce irrigated with magnetically treated water at different replacement rates. This approach is achieved using computational 4.0 software and manual methods. The aim of mathematical modeling is to understand or explain a natural phenomenon associated with a given area of knowledge, and fuzzy-rule-based systems have been widely used in different types of in-depth research.
Evidence of cytogenetic and histological damage in specimens of Astyanax lacustris (Pisces, Characidae) exposed to the hydrogen cyanide-based herbicide Dormex®
Authors: Zafra-Lemos Layon , Lopes Vera Lúcia , Rampazzo Ana Paula de Santi , Natali Maria Raquel Marçal , Borin-Carvalho Luciana Andreia , Portela-Castro Ana Luiza Brito
Published: April 2021

The herbicide Dormex®, a solution of hydrogen cyanamide, is a growth regulator capable of breaking the dormancy of fruit plants, and is commonly applied in agriculture. However, the biological effects of this product on non-target organisms are unknown. The present study investigated the biological response of Astyanax lacustris (Lütken, 1875) specimens exposed to Dormex® using a chromosome aberration test, the mitotic index, and the histological analysis of the gills. Forty specimens of Astyanax lacustris were obtained from a local breeding facility and divided into 10 groups (nine experimental and one control) with four fish in each aquarium (group). The control group was maintained for 24 hours in dechlorinated water while the experimental groups were allocated to one of nine different treatments, with three concentrations of Dormex®, 0.05, 0.1 and 0.5 mL L-1, and exposure for 24, 48 and 72 hours. The fish exposed to Dormex® presented chromosomal aberrations of a number of types, including chromosomal breaks, acentric fragments, decondensation, and gaps at the three Dormex® concentrations, at all exposure times. The mitotic index decreased significantly in comparison with the control group. The histological preparations of the gills revealed alterations such as hyperplasia, and lamellar fusion and edema, whereas in the control group the structure of the gills was preserved. The cytogenetic analysis revealed the genotoxic potential of the herbicide Dormex® and the morphological alterations of the gills demonstrated the sensitivity of the fish, which responded rapidly to the stressor. These findings reinforce the need for special care and restrictions on the use of these herbicides in agricultural areas located near aquatic environments.
Effect of essential oils on the development of Colletotrichum sp. fungus in fragments of Feijoa sellowiana fruits
Authors: Itako Adriana Terumi , Tolentino Júnior João Batista , Raduan José Luis França Pinto , Mattos Amanda do Prado , Santos Karine Louise dos , Ciotta Marlise Nara
Published: April 2021

The aim of this work was to evaluate the effect of the essential oils of Syzygium aromaticum, Cymbopogon citratus, Eucalyptus citriodora and Rosmarinus officinalis on the mycelial development of the fungus Colletotrichum sp. in fragments of Feijoa sellowiana fruits. The essential oils were incorporated in the PDA (Potato-Dextrose-Agar) medium in the concentrations of 250, 500 and 1000 ppm, 0 ppm (PDA only) (negative control), and fungicide fluazinam 1% (positive control). The area under the mycelial growth curve (AUMGC) and percent inhibition of mycelial growth (PIMG) were calculated. In the second evaluation, fruits fragments bordering the disease symptom were immersed in essential oils aqueous solution of S. aromaticum, C. citratus, and E. citriodora, at the concentration of 5000 ppm, 0 ppm (water only - negative control) and fluazinam 1% (positive control). The immersion times in the treatments were: 2, 4, 8, 12 and 24 hours, with subsequent incubation in Agar-Agar medium at 25°C. This evaluation was performed daily for 15 days, observing the moment of fungal germination through the emission of the mycelium. It was verified from the obtained results that all treatments reduced the fungal growth, and the essential oils of C. citratus and S. aromaticum totally inhibited its growth from the dose 500 and 1000 ppm, respectively. Regarding the test on fruit fragments, the essential oil of S. aromaticum at the immersion times of 12 and 24 hours was effective in inhibiting the fungus until the 15th day of evaluation.
Evaluation of the production of antifungal metabolites against Colletotrichum gloeosporioides in Streptomyces 5.1 by random mutagenesis
Authors: Castañeda-Novoa Carlos Daniel , Vinchira-Villarraga Diana Marcela , García Romero Ibonne Aydee , Moreno-Sarmiento Nubia
Published: April 2021

Streptomyces 5.1 is a bacterium isolated from rice soils in the south of the Tolima department (Colombia). This microorganism is characterized by its antagonistic activity against rubber tree phytopathogens like Colletotrichum gloeosporioides, the causal agent of leaf anthracnose. The antifungal activity of this Streptomyces isolate has been associated with secondary metabolites production. However, the identity of those metabolites is unknown because its purification and identification have not been possible through classic chemical studies. Therefore, aiming to contribute in the study of the secondary metabolites produced by 5.1 from a molecular approach, this research seeks to identify -preliminarily- the genomic fingerprint changes associated with the production of antifungal secondary metabolites produced by Streptomyces 5.1 through the evaluation of a mutant library of 5.1 obtained by random mutagenesis using controlled ultraviolet light exposure. The antifungal activity of obtained mutants was evaluated using Colletotrichum gloeosporioides (C1) fungus as a biosensor, isolated by the Biotechnology Institute of Universidad Nacional de Colombia. In this way, the library of mutants of 5.1, initially formed by 300 isolations, was classified into two phenotypic groups of interest: enhanced mutants (1 isolate) and null mutants (11 isolates) of secondary metabolites. The genomic changes in both groups were analyzed by obtaining the genomic profile of the isolates using Repetitive Extragenic Palindromic (Rep-PCR). The obtained profiles evidenced the presence of one additional band in the enhanced mutant, and the absence of a specific band in the non-producing mutants, both in comparison with the original strain. These bands are proposed for a future sequencing study which will define their role in the production process of metabolites with antifungal activity in Streptomyces 5.1.
Influence of High-Calcium Ash Composition on the Composite Binders’ Properties
Authors: Ignatova O. A. , Dyatchina A. A.
Published: April 2021

The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.
Serpentinite Magnesium Binders, Based on Technogenic Raw Materials
Authors: Zyryanova Valentina N. , Lytkina Evgeniya V. , Ochur-Ool Arzana P.
Published: April 2021

Increasing water resistance and mechanical strength of hardening magnesian binders’ products can be achieved by introducing microfillings into a hardening dispersed system. It is shown that serpentine provides an increase strength and water resistance in hydration and hardening process, being as a structure-forming component, it intensifies this process. It allows expanding the raw material base for the production of magnesia binders for construction purposes.
Stress State of 3D-Printed Plastic Dies at Thin-Sheet Aluminum Bending
Authors: Aksenov L.B. , Kononov I.Y. , Kolbasnikov N.G.
Published: April 2021

The paper deals with the problems and prospects of forming thin-sheet blanks, using ABS plastic dies, made by 3D printing. This technology combines the positive properties of plastic material and 3D-printing. The mechanical characteristics of the plastic were determined experimentally. On the basis of computer modeling, the dependence between the angle of bending the blank and the stresses arising in the dies is established. As a result of computer simulation and physical experiment, the value of the maximum thickness 0.5 mm for the aluminum 3003 blank is obtained. In this case, there is no plastic deformation of the plastic tool. The use of plastic dies does not require lubrication. The technology of sheet bending, using a plastic tool, can be implemented with the greatest efficiency in single and small-scale production.
Organic-Inorganic Composite for Extraction of Platinum(IV)
Authors: Lebedeva Oksana V. , Pozhidaev Yury N. , Raskulova Tatyana V.
Published: April 2021

A new composite adsorbent was obtained by hydrolytic polycondensation of N,N'-bis (3-triethoxysilyl propyl) thiocarbamide in the presence of poly-2-methyl-5-vinylpyridine. The sorption activity of the composite toward platinum (IV) ions was studied in hydrochloric acid solutions. The maximum extraction efficiency of Pt (IV) and the maximum values of sorptive capacity (218 mg g–1), and a coefficient of interphase distribution (7090 cm3 g–1) of the studied adsorbent in 1 М solution of HCl were found at 338 K. The Langmuir, Freundlich, and Dubinin–Radushkevich models were used to describe adsorption nature.
Synthesis of Amorphous Zirconium Dioxide from Zirconyl Nitrate in Presence of Oxalic Acid
Authors: Velyaev Yuriy , Kometiani Ilona , Miroshnichenko Olga
Published: April 2021

The article presents the results of studies on preparation of amorphous zirconium dioxide from zirconium nitrate by its hydrolysis in the presence of oxalic acid. It is determined that the balance of reagents taken for synthesis (1 ml 0,025 M ZrO(NO3)2 is 1.35 ml 4 M HOOC-COOH), and the optimum temperature of the received gel drying, which is 230 ̊С, is established, too. Morphology of the obtained ZrO2 samples was explored. It has been found that the calcining temperature is independent of the size and shape forming irregular agglomerates, consisting of smaller spherical particles, whose diameter varies between 50 and 300 nm. The X-ray analysis of the sample is represented, which showed a low degree of crystallinity of the substance. IR spectroscopy data showed the presence of zirconium dioxide-characteristic peaks on the IR spectrum. The same spectrum reflects the presence of a large amount of sorbed water in the obtained sample, as well as peaks characteristic of the gas adsorbed by the sample from the environment.
Technology for Preparation of Hybrid Sorbents Based on Plant Raw Materials and Montmorillonite
Authors: Koksharov Sergey A. , Lepilova Olga V. , Aleeva Svetlana V.
Published: April 2021

The possibility of preparation of hybrid nanocomposites, based on Burdock Arctium Lappa L biomass, modified with enzymes and montmorillonite, was substantiated. It was founded that bio-modification allowing releasing pectin into the biomass Burdock structure that allow fixing clay mineral particles onto biomass. It was found that the increase of pore spaces occurs at the expense of increasing mesopore spaces to 93 %. It allows increasing the adsorption capacity of hybrid nanocomposites to zinc ions and methylene blue to 52.2 and 166.9 mg g-1 respectively; that is 3.5 and 9 times more than adsorption capacityfor initial plant Burdock
Study of the Water-Glass Role in the Foam Glass Synthesis Using Glycerol Foaming Agent
Authors: Goltsman Boris M. , Yatsenko Lyubov A. , Goltsman Natalia S.
Published: April 2021

The article discusses the peculiarities of the "water-glass – glycerol" foaming mixture components interaction during foam glass synthesis. The important role of the foaming additive type in the foam glass porous structure formation was described, the main foaming substances were listed. The obtaining and researching technology of the samples was described, the compositions of the initial batches using the "water-glass – glycerol" mixture were developed. It was shown that a material with a highly porous structure and density below 500 kg/m3 can be obtained only with the combined introduction of water-glass and glycerol. In this case, mixtures with a predominance of water-glass in the foaming mixture possess optimal properties. Using DSC, it was shown that the addition of water-glass to the mixture completely eliminates the evaporation of glycerol at lower temperatures and intensifies its combustion at higher temperatures. Thus, the addition of water-glass to the glycerol-based foam glass batch allows glycerol to be saved up to higher temperatures that increases the resulting material porosity.
Mechanical Properties of Bio-Composites Based on Polymer Blends of Ethylene-Vinyl Acetate Copolymer and Polyethylene with Natural Fillers
Authors: Shelenkov P.G. , Pantyukhov P.V. , Popov A.A.
Published: April 2021

Highly filled bio-composites based on ethylene-vinyl acetate copolymer (EVA) with cellulose and wood flour were prepared in the previous parts of the study. The aim of this work was to dilute them with a polyethylene (PE), to prepare new bio-composites with lower EVA content and to investigate the effect of EVA/PE ratio on the mechanical properties. It was shown that melt flow index (MFI) and elongation at break increased additively with an increase of EVA content in the composition, but yield strength had an inverse tendency. The obtained results are extremely useful for choosing the right composition for the industrial implementation.
Kinetics and Adsorption Ions of Heavy Metal by Modified Alumino-Silicates
Authors: Filatova Elena G. , Pozhidaev Yury N.
Published: April 2021

Adsorption isotherms of Ni (II) and Cu (II) ions by alumino-silicates, modified with N, N'-bis (3-triethoxysilylpropyl) thiocarbamide (BTM-3), and HCl, were obtained. The adsorption kinetics of heavy metal ions is studied, using the kinetic pseudo-first and pseudo-second order models. It is shown that, when alumino-silicates are modified, the rate and energy of adsorption increase. It is established that the kinetics of the adsorption of the studied ions is best described by a pseudo-second order model. The maximum value of the adsorption rate constant of 33.7∙10-5 g/ (mmol min) corresponds to nickel (II) ions for alumino-silicates, modified with HCl. The maximum value of the adsorption rate constant value of 2.91∙10-5 g/ (mmol min) for alumino-silicates, modified with BTM-3, corresponds to Cu (II) ions.
Resonance Method of Determination of Interacting Force of Particles in the Cluster of Ferromagnetic Material
Authors: Lebedev Valery A. , Vernigorov Y.M. , Chunakhova L.V.
Published: April 2021

Anisotropy of a powder ferromagnetic product can be created by focusing separate particles in the direction of a certain crystallographic axis in a magnetic field. By fitting modes of electromagnetic field it is possible to regulate the intensity of clusters movement and powder particles, as well as to destroy clusters up to the separate particles. At the increase of constant magnetic field induction up to a certain value, typical for every material, the intensification of processes of secondary aggregation and formation of anisotropic layer structure takes place. A design model of magneto-vibrational state of finely divided powder suggested in the article enables to calculate the parameters of electromagnetic field, which provide optimal characteristics of a powder product. It has been shown that, at a certain ratio of parameters of electromagnetic field in a dispersive ferromagnetic medium, a chain system is formed. The chains are focused along magnetic-field lines and execute a vibration in a variable inhomogeneous magnetic field, according to the law of a string with fixed ends.
Micro-ECM of the Aerodynamic Surface Understating
Authors: Morgunov Yuriy A. , Petukhov S.L. , Saushkin B.P.
Published: April 2021

This paper demonstrates that 18 μm deep surface understating with a tolerance of 4.5 μm and a roughness Ra=0.4 μm can be produced to the required accuracy by electrochemical die-sinking if configured appropriately.Theoretical analysis shows that the bottom profile error can be presented as a superposition of the errors of surface alignment (non-parallel bottom) and shape (non-flat bottom). In this case, the alignment error accounts for a greater part of the size tolerance (3 μm out of 4.5 μm). This is why the attainment of desired accuracy revolves around the development, analysis, and assessment of ways to reduce this error.
Structural Heredity of Cast Iron in Bimetallic Products
Authors: Astashchenko V.I. , Mukhametzyanova G.F. , Mukhametzyanov I.R.
Published: April 2021

Properties of cast iron on the bimetallic part depend on the initial structural state of the cladded cast iron and technological parameters of its induction cladding process. Methodology of predicting the properties of the cast iron in the bimetallic valve tappets ICE largest hardness billets was used for cladding, the silicon content in the alloy cladding and the technological parameters of the process, as well. A hereditary relationship between the initial state of the cast iron of the semi-finished product, used for induction cladding, and the structural state of the layer of weld on the steel base of the part, has been established.
Prediction of Mechanical Properties of Ti-6AI-4V Titanium Alloy Bars Depending on Aluminum and Molybdenum Strength Equivalents
Authors: Egorova Yuliia B. , Davydenko Lyudmila V. , Shmyrova Alisa V.
Published: April 2021

The article provides the results of a statistical research of the relation of mechanical properties and chemical composition of Ø 15-rolled, forged, and pressed bars made of various modifications of the Ti-6Al-4V titanium alloy. The authors studied the correlation of mechanical properties and the content of alloying elements, impurities, bar diameter, and post-annealing (using various industrial modes) structural parameters, on the basis of the analysis of production data, and established regression dependencies for estimating average values of mechanical properties of bars on aluminum and molybdenum strength equivalents of alloying elements and impurities.
Forging Process Flow Development for Plate Production
Authors: Kobelev Oleg , Valeeva Lilya M. , Gerasimova Alla A.
Published: April 2021

Developed on the basis of the pilot and industrial work results, a process flow for the production of mono-block plates with 7600x7600x360 mm dimensions from a 290-ton ingot for subsequent 15H2NMFA steel bottom stamping, was carried out. A practical implementation of the developed procedure for the bottom production from mono-block large-sized plates was made. The basic technology for the mono-block plate production was applied in the conditions of Izhorskiye Zavody, OJSC and Atommash, OJSC, this technology provides for a minimum amount of reconstruction of the existing facilities of these enterprises.
Formation of a Gradient Structure in Austenitic Stainless Steel AISI 321 by Radial-Shear Rolling
Authors: Naizabekov Abdrakhman B. , Lezhnev Sergey N. , Panin Evgeniy
Published: April 2021

One of ways to increase the strength of a structural material is to grind its microstructure to an ultra-fine-grained state. But with the simultaneous increase in strength properties in ultrafine materials, there is an inevitable decrease in its plastic properties. The use of metal materials with a gradient structure is an effective way to solve the problem of increasing the plasticity of metal products in general. This work is devoted to the study of the possibility of a gradient structure forming in austenitic stainless steel AISI-321 using radial-shear rolling. The results of the studies showed that the UFG-structure extends in the bar from its surface to a depth of at least a quarter of the radius of the bar. The transition zone is in the region between 0.5 R and 0.25 R of the bar section. Anything deeper is rolling texture. Due to the structural heterogeneity of the cross-section of the bar, there is a smooth drop in the micro-hardness of the central zone of the bar by 10.2 %. All this testifies to the gradient character of the structure formed in bars of AISI-321 steel deformed on the radial-shear rolling mill.
Isothermal Heat Treatment of the Low-Carbon Martensitic Steel
Authors: Maisuradze Mikhail V. , Kuklina Aleksandra A. , Lebedev Dmitriy I.
Published: April 2021

A study of the low-carbon steel with high hardenability was carried out. The steel contained the following alloying elements, wt. %: C – 0.20; Cr – 2.0; Mn – 2.0; Si – 1.04 Ni – 1.0; Mo – 0.3. The quenching – partitioning treatment of the studied steel was implemented. The microstructure of the steel consisted of the tempered martensite laths, bainite and martensite-austenite regions. The amount of the residual austenite and the carbon concentration in the residual austenite were estimated. The possibility of the quenching – partitioning treatment of the carburized steel was shown.
The Effect of Microstructure and Temperature Gradient on Radiation-Induced Swelling of Austenitic Steel
Authors: Pastukhov Vladimir , Averin Sergey , Lobanov Mikhail L.
Published: April 2021

Radiation porosity through-thickness of the fuel pin cladding, made of 16Cr-19Ni-2Mo-2Mn-Nb-Ti-V-P-B steel, has been studied with scanning electron microscopy using backscattered electron (BSE) detector. The examined sample was irradiated at a temperature around 480 °С up to an integral damage dose of 87 dpa. It was shown that, due to the temperature gradient through the cladding thickness, the average size of radiation voids reduces, and their concentration increases from internal to external surface. Local nonuniformity of radiation porosity is observed in regions close to internal and external surfaces. It was shown that, non-uniformity of radiation porosity is determined by the material structure, microtwin density and high concentration of low-angle inter-granular boundaries, in particular.
Selection of Rational Deformation Pressing Modes in a Special Device
Authors: Uderbayeva Assemgul , Rakhmatulina Rakhmatulina , Nurakhmetova Gulzira
Published: April 2021

Various types of deformed semi-finished products are prepared from aluminum alloys, such as plates, sheets, tapes, foil, panels, profiles, pipes, rods, forged pieces, wires. These semi-finished products are obtained by processing ingots of continuous casting by pressure - rolling, rolling-off, pressing, forging, stamping or drawing. Pressed semi-finished products are made of aluminum alloys in the majority of cases. The work examines the study of the evolution of the half-finished products microstructure at different stages of their manufacturing in several passes and shows the possibility of obtaining strips of fine-grained structure using pressing in a special device. Also, the research established that, in the material of half-finished product from the AD31 aluminum alloy the smooth fine-grained structure is formed with grains of 6 - 17 μm, which leads to an increase in the strength properties of the alloy and to a preservation of good plasticity.
Evaluation of the Effect of Holding the Mandrel in the Extreme Position of the FQM Mill on the Formation of Surface Defects
Authors: Toporov Vladimir , Khalezov Alexander , Nukhov Danis Sh.
Published: April 2021

Modern continuous mills FQM are high-performance technological units that allow you to get products of a wide range. The paper presents the results of the study of the effect of the time of holding the mandrel in the extreme position of the continuous mill FQM (Fine Quality Mill) on the probability of defect formation of surface defects. The problems of сcomputational simulation of the process of continuous rolling of pipes were set and solved. It is established that the increase in the holding time of the mandrel allows to reduce the sliding of the metal on the surface of the tool, and contributes to a stable process of removing the mandrel without the formation of defects on the inner surface of the draft pipe. The results of solving the problems of сcomputational modeling allowed to formulate technical recommendations aimed at reducing the probability of surface defects in the production of pipes at the FQM mill.
Metallization of Oolitic Iron Ore after Oxidation Firing
Authors: Suleimen B. , Salikhov S.P.
Published: April 2021

Firing and metallization of brown iron ore from the Ayat deposit were investigated in present research. In order to remove carbon dioxide, carbonates, hydrated moisture and sulfur from the ore and convert goethite to hematite the oxidation firing was carried out in a Nabertherm muffle furnace at temperature of 900 ° C for 10 minutes. The effect of reduction of temperature was studied, by CO gas at 800, 900, 1000, 1050 ° C, for 3hours reduction time. The chemical composition of the initial and fired ore, as well as magnetic and non-magnetic parts of the reduced samples were studied by using an electron microscope. It was observed that at temperature of 800 ° C iron and phosphorus were not reduced. The metallized material with a low phosphorus content (0.1at%) was obtained at temperature of 1050 ° C.
Thermal State Simulation of Welded Steel Plates under Laser Welding Conditions
Authors: Ivanchenko Aleksandr , Tochilin I.P. , Zhdanov Aleksey V.
Published: April 2021

The article describes a method for determination of the welded parts temperature pattern under laser welding conditions. An algorithm is engineered to solve the non-stationary heat conduction problem by finite element method. The boundary conditions are determined by the molten pool parameters and depend on the welding regime characteristics. The dependencies for determining the molten pool geometric dimensions for laser welding conditions are proposed. Calculations of the temperature pattern change during the steel plates joint by laser welding are carried out. It is shown that the proposed model adequately describes the heat transfer process in the welding region.
Technology and Equipment for Rolling of Bimetallic Bars with Multilateral Reduction
Authors: Samodurova Marina N. , Barkov Leonid A. , Latfulina Yuliya S.
Published: April 2021

The article describes the technology and equipment used at the enterprises of the Russian Federation in 70-90 years in the XX century for the production of bimetallic rods, the basis of the new technology is described, and the designs of mills with multi-roller calibers are presented. New mill designs, patented in the U.S., Japan, Europe and other countries, have a fairly simple design, with the use of multi-roller mills it is possible to use drives from conventional two-roller mills, the presence of radial and axial adjustment of the rolls extends the technological capabilities of the mill, the calibers of different sizes can be obtained on a single set of rolls. On such mills it is possible to obtain sections from low plastic, difficult to deform materials, as well as bimetallic compositions. These products are in high demand in aviation, space, engineering and many other industries, which are strategic directions of the state development.
The Study of the Copper Alloy Structure and Properties
Authors: Brusnitsyn Sergey V. , Gruzdeva Irina A. , Sokolov Ivan A.
Published: April 2021

This paper is devoted to the possibility of using tin as an alloying element in a copper alloy for the contact wire manufacture for high-speed electrified railways. To this end, laboratory experiments were carried out to determine the effect of tin on the structure, mechanical and electrical properties of samples, made of low-alloy system Cu-Sn alloys, under the cold deformation. Cast rods and rolled billets of CuSn0,2, CuSn0,4 and CuSn0,6 alloys are made. The cast rods macrostructure is studied. The analysis showed that with the introduction of tin into copper, there is no zone of columnar crystals in the macrostructure. Moreover, it was found that grains of α-solid solution of tin in copper have a shape close to equiaxial. A structure analysis of rolled billets showed that an increase in the deformation degree leads to grinding of crystalline grains. The mechanical properties of rolled billets were determined: ultimate tensile strength σU, offset yield strength σ0.2 and elongation δ50. The dependence of the electrical resistivity of rolled billets on the deformation degree and the tin content in the alloy is determined. Еhe higher the tin content in the alloy and the deformation degree is, the higher is the electrical resistivity. The electrical resistivity of samples, made of CuSn0.2 and CuSn0.4 alloys, coincides with the GOST R 55647-2018 requirements. The laboratory studies have shown that tin-containing copper alloys (Sn is up to 0.4 wt. %) can be recommended as a material for the manufacture of contact wire.
Influence of the Melt Treatment Method on the Properties of Cast Iron
Authors: Afanasyev Vladimir K. , Sagalakova Marina M. , Tankov Evgeny V.
Published: April 2021

The article is devoted to studying the effect of liquid melt treatment with a substance having high affinity with hydrogen – lead-base silumin. Taking into account that gases (hydrogen, nitrogen and oxygen) are present everywhere, including alloys, a series of experiments was carried out on treating melt of blast furnace iron with substances having great affinity with hydrogen. It is established: when treating melt with lead-base silumin in the low-temperature test interval, there is a slight increase in the linear expansion coefficient (LEC) at 100°C, compared with the initial one, to 8.210-6, deg-1. In the temperature range of 100-150°C LEC decreases to a minimum value of 7.210-6, deg-1. In the average temperature range of 150-300°C, a sharp, anomalous increase is noticeable, compared with the initial one up to 15.5210-6, deg-1. When studying the microstructure of cast iron after processing the melt with lead silumin, the formation of ledeburite structure is stated. Samples treated with lead-base silumin were subjected to cementation by feeding water steam at 900°C for 1-5 hours. It should be noted that, in the temperature range of 50-150°C, the values of the linear expansion coefficient lie almost in a straight line in the entire field of study. The coefficient varies from 10.810-6, deg-1 at 50°C to 13.710-6, deg-1 at 450°C. Preliminary heat treatment of cast iron in the carburizer made by the Bondyuzhsky plant with water steam smoothes anomalies of LEC and increases its initial values, and grinds perlite and cementite as well. Subsequent quenching in water with a temperature of 1000°C significantly changes the linear expansion coefficient of cast iron. Hardening of samples after cementation sharply reduces the linear expansion coefficient in the test range of 150-200°C, and in the temperature range of 350-450°C negative values of LEC are observed. Thus, it can be concluded, that treating the melt with lead-base silumin, cementation in the medium of the carburizer made by the Bondyuzhsky plant and subsequent hardening leads to sharp changes of the linear expansion coefficient up to negative values. The identified properties suggest the possibility of using cast iron where it is necessary to constancy of LEC and there are no requirements for the weight of the product.
Influence of Type and Consumption of Pellets on Indicators of Blast-Furnace Smelting in the JSC Ural Steel
Authors: Dema Roman R. , Shapovalov Aleksey N. , Kal'chenko Aleksandr A.
Published: April 2021

The article presents the results of the analysis of production data on the operation of the blast furnace No. 1 of Ural Steel JSC for the period from 2013 to 2018. During this period, the Mikhailovsky GOK pellets with different basicities were used. It has been established, that the effectiveness of the use of pellets of different basicities is determined by their behavior in a blast furnace and depends on the proportion of pellets in the iron ore part of the charge. The gas-dynamic conditions of melting deteriorate with an increase in the proportion of pellets in the charge, which is accompanied by an increase in the specific pressure drop and forces the blast rate, to be adjusted. It is necessary to work on 40-45% of fluxed pellets and 20-25% acid pellets in a charge at a blast rate of 2000-2100 m3/min, to minimize coke rate and increase rate of work of blast furnace No. 1 of Ural Steel JSC. An increase in pellet consumption is possible while maintaining the efficiency of blast-furnace smelting only if their high-temperature properties are improved, as a result of optimization of basicity and increase in MgO content, which affects the structure and properties of the silicate binder.
Production of Primary Silumins Ingots Modified with Strontium
Authors: Kuz'min Mikhail P. , Kuz'mina Marina Yu. , Kuz'min Petr B.
Published: April 2021

The article examines a number of regularities in the production of primary cast ingots of AlSi7Mg, AlSi7MgSr, AlSi11Mg, and AlSi11MgSr. Peculiarities of melting and cast of these alloys, as well as the effect silicon and strontium have on the formation of the shrinkage cavities, have been explored. It has been demonstrated that strontium, when used as a modifier, changes not only the morphology of silicon, but also the nature of solidification and shrinkage of the alloy. Defects formed in the ingots manufactured from near – eutectic AlSi11MgSr alloy have been studied in greater detail.
Transfer of Abrasive Material at Grinding a Titanium Alloy with a Wheel of Cubic Boron Nitride
Authors: Nosenko Vladimir A. , Fetisov Alexander V. , Kuznetsov Semen P.
Published: April 2021

The article summarizes the results of the of the titanium alloy surface morphology and chemical composition study after grinding with a wheel of cubic boron nitride on a ceramic bond. The titanium alloy was treated using the method of cut-in grinding in the finishing mode using a synthetic water-soluble lubricant-cooling liquid that does not contain mineral oil. The research was carried out using the FEI Versa 3D LoVac electron microscope. Digital photos of the titanium alloy surface at different magnifications are given. Individual objects’ morphology allows us to identify them as wear products of abrasive tools. The chemical composition of the selected objects was studied by local x-ray spectral analysis. CBN crystals are partially or completely pressed into the treated surface and covered with a layer of the treated material. On the surface of CBN crystals, there are chemical elements that are part of the abrasive tool bond.
Microstructural Features and Properties of Al-Cu-Mg Alloy Containing Silver and Cerium
Authors: Reznik Pavel L. , Ovsyannikov Boris V.
Published: April 2021

The article presents the results of an investigation of microstructural features and mechanical characteristics of Al-5.0Cu-0.5Mg alloy containing up to 0.4 wt. % Ag and up to 0.1 wt. % Ce. The experiment was conducted using optical microscopy, Scanning Electron Microscopy as well as an electron probe micro-analyzer and Differential Scanning Calorimetry. Samples in cast condition and after heat treatment were examined. The melting temperatures of non-equilibrium eutectics (non-equilibrium solidus), equilibrium solidus and liquidus were determined. The optimal temperature of the homogenizing heat treatment was determined, which was 500°C. Using this heat treatment mode resulted in the elimination of dendritic segregation and complete dissolution of silver in aluminum. Injection of cerium into the Al-Cu-Mg-Ag system during crystallization of the melt is accompanied by the formation of a coarse four-component phase, which has the morphology of polyhedrons, is on the grain boundaries. The estimation of the relation between microstructure characteristics and mechanical properties of the alloy has been made.
Selective Laser Melting AlSi12 Alloy by Utilizing of Non-Spherical Air-Atomized Powder
Authors: Baitimerov R.M. , Bryk A.V.
Published: April 2021

AlSi12 alloy is one of the most widely used materials in selective laser melting. Selective laser melting (SLM) of AlSi12 alloy has been well studied in recent years. Researchers typically use very expensive spherical powders atomized in an inert atmosphere. For this paper, we studied SLM of air-atomized non-spherical powder to determine its printability. Nine specimens were fabricated using different SLM process parameters. The lowest porosity that was achieved was 1.3%.
Characteristics of Powders from Different Aluminum Alloys for Additive Technologies Obtained by Gas Atomization
Authors: Lykov P.A. , Glebov L.A.
Published: April 2021

Selective laser melting (SLM) is one of the additive manufacturing technologies that allows us to produce complex shape metallic objects from powder feedstock. Al-alloys are very promising materials in selective laser melting. In this paper, atomized metal powders of various aluminum alloys are investigated: 1) deformable alloys АК4, АК6; 2) cast alloys АК9ph, АК12; 3) deformable hardened alloy D16. As a part of the work, the particle shape, particle size distribution and technical characteristics of the powders were investigated, and also the compliance of materials with the requirements of additive technologies (SLM) was determined.