scholarly journals IMPREGNATION OF POROUS METAL CASTING WITH POLYMER COMPOSITIONS: CURRENT TRENDS

2020 ◽  
pp. 55-61
Author(s):  
I. O. Leushin ◽  
A. U. Subbotin ◽  
D. A. Gorokhov
Keyword(s):  
Block Diagram ◽  
Practical Interest ◽  
Porous Metal ◽  
Polymer Materials ◽  
Current Trends ◽  
Impregnating Compound ◽  
Sealing Materials ◽  
Cast Parts

Modern sealing materials for impregnation of cast parts are considered, as well as types of casting defects that require such processing. The block diagram of impregnation is given, its operations are described. A classification of modern methods of impregnation of castings with polymer materials is proposed, and the results of their comparative evaluation are presented. The most practical interest among manufacturers is the method of impregnation «wet vacuum / pressure» in combination with the use of the impregnating composition Loctite Resinol 88 C. This is due to the best combination of price and quality of the sealant, as well as the fact that this impregnating compound can withstand the highest temperature (250 °C) compared to its analogues and is characterized by the lowest consumption when processing products (1.5 g/kg).

scholarly journals Possibility for Replicating Mechanoscopic Surface Marks in the Hybrid Vacuum-Pressure Casting Process

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 874
Author(s):  
Mariusz Frankiewicz ◽  
Karol Kobiela ◽  
Tomasz Kurzynowski
Keyword(s):  
Geometrical Structure ◽  
Casting Process ◽  
Polymer Materials ◽  
Vacuum Pressure ◽  
Pressure Casting ◽  
Main Research ◽  
Casting Technology ◽  
The Individual ◽  
Cast Parts

Vacuum-pressure casting technology allows small batches of components to be manufactured from polymer materials, mainly from thermosetting plastics such as polyurethane and epoxy resins. Apart from being very simple, the process is also advantageous in that it offers a very accurately reproduced geometrical structure of the surfaces of master patterns used in mold manufacturing. This article presents the results of analyses performed for the process of replicating mechanoscopic marks with the use of three vacuum casting variants, including a hybrid vacuum-pressure casting process developed in particular for the replication purposes. The main research objective was to analyze and evaluate the influence of the parameters of the individual process variants on the quality of the obtained cast parts and on the replication accuracy without introducing additional artifacts on their surfaces. The article discusses the individual stages of the process and provides an analysis of their parameters. The replicas were evaluated for their porosity and reproduction quality with the use of CT methods and comparative photographs obtained from a light microscope.

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

Paepalanthus fabianeae (Eriocaulaceae): A New Microendemic Species from a Morphologically Coherent Clade

2020 ◽  
Vol 45 (4) ◽  
pp. 794-801
Author(s):  
Caroline Oliveira Andrino ◽  
Marcelo Fragomeni Simon ◽  
Jair Eustáquio Quintino Faria ◽  
André Luiz da Costa Moreira ◽  
Paulo Takeo Sano
Keyword(s):  
New Species ◽  
Iucn Red List ◽  
Phylogenetic Position ◽  
Similar Species ◽  
Infrageneric Classification ◽  
Espinhaço Range ◽  
Nuclear Its ◽  
Two Populations

Abstract—We describe and illustrate Paepalanthus fabianeae, a new species of Eriocaulaceae from the central portion of the Espinhaço Range in Minas Gerais, Brazil. Previous phylogenetic evidence based on analyses of nuclear (ITS and ETS) and plastid (trnL-trnF and psba-trnH) sequences revealed P. fabianeae as belonging to a strongly supported and morphologically coherent clade containing five other species, all of them microendemic, restricted to the Espinhaço range. Due to the infrageneric classification of Paepalanthus being highly artificial, we preferred not assigning P. fabianeae to any infrageneric group. Paepalanthus fabianeae is known from two populations growing in campos rupestres (highland rocky fields) in the meridional Espinhaço Range. The species is characterized by pseudodichotomously branched stems, small, linear, recurved, and reflexed leaves, urceolate capitula, and bifid stigmas. Illustrations, photos, the phylogenetic position, and a detailed description, as well as comments on habitat, morphology, and affinities with similar species are provided. The restricted area of occurrence allied with threats to the quality of the habitat, mainly due to quartzite mining, justifies the preliminary classification of the new species in the Critically Endangered (CR) category using the guidelines and criteria of the IUCN Red List.

MEDIATEXT IS A TOOL THAT DETERMINES THE QUALITY OF INFORMATION

2020 ◽  
Vol 6 (3) ◽  
pp. 158-164
Author(s):  
Navruza Yakhyayeva ◽  
Keyword(s):  
Functional Properties ◽  
Linguistic Features ◽  
Text Linguistics ◽  
Quality Of Information ◽  
The Creation ◽  
Linguistic Units ◽  
Scientific Classification

The quality and content of information in the article media text is based on scientific classification of linguistic features. The study of functional styles of speech, the identification of their linguistic signs, the discovery of the functional properties of linguistic units and their separation on the basis of linguistic facts is one of thetasks that modern linguistics is waiting for a solution. Text Linguistics, which deals with the creation, modeling of its structure and the study of the process of such activity, is of interest to journalists today as a science.

IMPROVEMENT OF CLASSIFICATION OF FACTORS AFFECTING THE QUALITY OF SILICON CONNECTIONS IN SEWING PRODUCTS

2019 ◽  
pp. 86-88
Author(s):  
R. H. Batirova ◽  
S. S. Tashpulatov ◽  
I. V. Cherunova ◽  
M. A. Mansurova ◽  
S. L. Matismailov
Keyword(s):  
Factors Affecting

LEARNING MATERIALS: THE “NUCLEUS” OF LANGUAGE TEACHING

2018 ◽  
Vol 3 (1) ◽  
pp. 1-8
Author(s):  
Desy Damayanti ◽  
Adin Fauzi ◽  
Azizatul Mahfida Inayati
Keyword(s):  
Language Teaching ◽  
Language Teachers ◽  
Learning Materials ◽  
Authentic Materials ◽  
Authentic Texts ◽  
Radio Broadcasting ◽  
Language Classroom ◽  
Level Of Understanding

Among some components of effective language classroom, learning materials indisputably play a focal role. They improve the quality of language teaching; facilitate teachers in doing their duties, and lead students to a higher level of understanding in learning. This research aims to discuss the notion of materials in language teaching. It made use of works of literature to outline the importance of materials in language teaching, and to analyze kinds of materials, which are relevant to language teaching. The analysis resulted in the classification of materials into two broad categories namely (1) created materials, which include course book, audio materials, and video materials; and (2) authentic materials, which cover authentic texts, movie/film, radio broadcasting, television program, graphs, maps, tables, and charts. This paper serves as an invaluable resource to facilitate language teachers in selecting appropriate materials for effective language teaching.

Current Progress in Biomedical Applications of Chitosan-Carbon Nanotube Nanocomposites: A Review

2020 ◽  
Vol 20 (16) ◽  
pp. 1619-1632
Author(s):  
Katarzyna Pieklarz ◽  
Michał Tylman ◽  
Zofia Modrzejewska
Keyword(s):  
Carbon Nanotube ◽  
Medical Science ◽  
Antimicrobial Properties ◽  
Polymer Materials ◽  
Biological Macromolecules ◽  
Medical Sciences ◽  
New Generation ◽  
High Degree ◽  
Dressing Materials

The currently observed development of medical science results from the constant search for innovative solutions to improve the health and quality of life of patients. Particular attention is focused on the design of a new generation of materials with a high degree of biocompatibility and tolerance towards the immune system. In addition, apart from biotolerance, it is important to ensure appropriate mechanical and technological properties of materials intended for intra-body applications. Knowledge of the above parameters becomes the basis for considerations related to the possibilities of choosing the appropriate polymer materials. The researchers' interest, as evidenced by the number of available publications, is attracted by nanobiocomposites based on chitosan and carbon nanotubes, which, due to their properties, enable integration with the tissues of the human body. Nanosystems can be used in many areas of medicine. They constitute an excellent base for use as dressing materials, as they exhibit antimicrobial properties. In addition, they can be carriers of drugs and biological macromolecules and can be used in gene therapy, tissue engineering, and construction of biosensors. For this reason, potential application areas of chitosan-carbon nanotube nanocomposites in medical sciences are presented in this publication, considering the characteristics of the system components.

Coordination of technology of railway operation of the Republic of Tajikistan and organization of railways in international traffic

2018 ◽  
Vol 77 (4) ◽  
pp. 211-217 ◽  
Author(s):  
P. N. Pulatov
Keyword(s):  
Rolling Stock ◽  
Railway Transport ◽  
Transport Services ◽  
Railway Infrastructure ◽  
External Conditions ◽  
The Republic ◽  
Railway Operation ◽  
Required Quality

Current geopolitical and economic conditions for the functioning of railway transport in most post-Soviet states are such that it is extremely difficult to provide required quality of transport services and break-even operations at high expenses for maintaining the railway infrastructure and rolling stock. Dynamics of transportation of the Tajik Railway (TSR) is shown, which displays that most of its sections are classified as low-intensity ones. The paper proposes methodical principles, setting and qualitative analysis of the task of rationalization of operational work and organization of car flows for international transportation, taking into account the specifics of the Tajik Railway. There is a problem of complex maintenance of the efficiency of operational work in modern conditions based on the synthesis of the tasks of self-management (rational internal operational technology of the Tajik Railway) and coordination tasks (technological interaction with railway administrations of other states). Author substantiated the necessity of solving this problem. Proposed classification of technological restrictions and controlled variables in the performance of transport takes into account methods for changing external conditions for the functioning of the railway landfill and methods for increasing internal efficiency of its operation. The search for the solution of the problem involves direct search of variants along its ordered set with clipping of groups of variants that do not correspond to constraints, with the subsequent finding of compromise control over a set of effective alternatives.

scholarly journals Assessment of quality of products from polymer materials for machine-building purposes

2020 ◽  
Vol 1614 ◽  
pp. 012044
Author(s):  
D Gramakov ◽  
A Larchenko ◽  
N Filippenko ◽  
A Livshits ◽  
D Bakanin ◽  
...  
Keyword(s):  
Machine Building ◽  
Polymer Materials ◽  
Quality Of Products

scholarly journals Classification of endonasal HHT lesions using digital microscopy

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
F. Haubner ◽  
A. Schneider ◽  
H. Schinke ◽  
M. Bertlich ◽  
B. G. Weiss ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Treatment Modalities ◽  
Hereditary Haemorrhagic Telangiectasia ◽  
Digital Microscopy ◽  
Digital Microscope ◽  
Lower Severity ◽  
Gender Specific Differences ◽  
Vegf Level

Abstract Background Recurrent spontaneous epistaxis is the most common clinical manifestation and the most debilitating symptom in hereditary haemorrhagic telangiectasia (HHT) patients. To this date, there exist only a classification of HHT patients by different genetic mutations. There is no standard classification for the mucocutaneous endonasal manifestations of HHT. The aim of the present study was to document the variety of endonasal HHT lesions using digital microscopy and to propose a clinical classification. Methods We recorded the endonasal HHT lesions of 28 patients using a digital microscope. We reconstructed the 3D images und videos recorded by digital microscope afterwards and classified the endonasal lesions of HHT in two classes: Grade A, presence of only flat telangiectasias in the mucosa level and Grade B, (additional) presence of raised berry or wart-like telangiectasia spots. We investigated also Haemoglobin level by routine laboratory procedures, plasma VEGF level by ELISA, Severity of epistaxis by epistaxis severity score (ESS) and quality of life by a linear visual analogue scale (VAS). Results We found a higher quality of life and a lower severity of epistaxis in Grade A patients in comparison to Grade B patients. No difference in plasma VEGF level and in Haemoglobin between Grad A patients and Grade B patients could be detected. Plasma VEGF levels showed no gender specific differences. It could also not be correlated to the extranasal manifestation. Conclusion The classification for endonasal manifestation of HHT proposed in this study indicates severity of epistaxis und quality of life. Digital microscopy with the ability of 3D reconstruction of images presents a useful tool for such classifications. The classification of endonasal HHT lesions using digital microscopy allows to evaluate the dynamic of HHT lesions in the course of time independent of examiner. This allows also to evaluate the efficacy of the different treatment modalities by dynamic of HHT lesions. Moreover digital microscopy is very beneficial in academic teaching of rare diseases.

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