scholarly journals Design of compositions and types of structures of injection molded dispersed filled thermoplastics with good processability and high strength

2021 ◽  
pp. 10-12
Author(s):  
I. D. Simonov-Emelianov ◽  
D. D. Krechetov ◽  
K. I. Kharlamova

The issues on the assessment of rheological properties of dispersed filled polymer composite materials (DFPCM) in terms of generalized parameters of disperse structure are considered. The dependences of pressure loss during injection molding of thin-walled DFPСM products with different types of disperse structure: dilute, low-filled, medium-filled and high-filled systems are given for the first time. It has been established that to obtain DFPCM based on thermoplastics with good processing properties and products with high strength, it is necessary to create materials having medium-filled type of structure and the generalized parameter Θ ≈ 0.5-0.6 vol/vol. The algorithm for calculating the dispersed filler content with known basic properties to provide a given type of DFPCM structure is proposed.

2020 ◽  
pp. 4-7
Author(s):  
I. D. Simonov-Emelyanov

For the first time, calculations of compositions of dispersion-filled polymer composites with given structure parameters are presented, which take into account the construction of an infinite cluster, various types of lattices, the main parameters of lattices - coordination number (Z) and packing density (kуп) according to the De Gennes – Shklovsky model, as well as generalized parameters of structures (Θ), shape, size, maximum packaging (φm) and content of dispersed filler (φн).The dependencies and tabular data on the relationship of lattice parameters (Z, kуп) with the generalized parameter Θ (the proportion of the polymer matrix for the formation of a continuous interlayer between dispersed particles) of the composite structure are given, which determine the content of the filler to create a dispersed structure with specified parameters and properties.


Alloy Digest ◽  
1976 ◽  
Vol 25 (1) ◽  

Abstract ATLANTIC 13B Alloy is a silicon bronze casting alloy offering excellent castability and corrosion resistance, good machinability and medium-high strength. It is an all-purpose alloy that is suitable for gears, valve parts and marine fittings. It is especially useful in stress-corrosion environments for thin-walled parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Cu-307. Producer or source: Atlantic Casting and Engineering Corporation.


Alloy Digest ◽  
1977 ◽  
Vol 26 (10) ◽  

Abstract ZA-27 is a zinc-aluminum-copper alloy that offers exceptionally high strength (58,000 to 64,000 psi tensile strength as cast) at modest cost. It performs best in thin-walled castings (down to 0.10 inch) which means reduced weight and lower material costs when castings are redesigned. It is similar to the general-purpose ZA-12 alloy (Alloy Digest Zn-31, September 1977) except for its higher strength and elongation, but with higher casting temperatures and poor heavy-section castability. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fracture toughness and creep. It also includes information on corrosion and wear resistance as well as casting, forming, heat treating, machining, and surface treatment. Filing Code: Zn-32. Producer or source: Eastern Alloys Inc.. See also Alloy Digest Zn-50, June 1990.


Author(s):  
Vladimir A. Lapin ◽  
Erken S. Aldakhov ◽  
S. D. Aldakhov ◽  
A. B. Ali

For the first time in Almaty full passport of apartment stock of multiapartment building was carried out. The structure of the housing stock was revealed with the allocation of groups of buildings according to structural solutions and assessment of their seismic resistance. Based on the results of certification, quantitative estimates of failure probability values for different types of buildings were obtained. Formulas for estimation of quantitative value of seismic risk are obtained. The number of deaths in the estimated zem-shakes was estimated. The results of the assessments will be used for practical recommendations to reduce risk and expected losses in possible earthquakes.


Author(s):  
Jack Corbett ◽  
Wouter Veenendaal

Chapter 1 introduces the main arguments of the book; outlines the approach, method, and data; defines key terms; and provides a chapter outline. Global theories of democratization have systematically excluded small states, which make up roughly 20 per cent of countries. These cases debunk mainstream theories of why democratization succeeds or fails. This book brings small states into the comparative politics fold for the first time. It is organized thematically, with each chapter tackling one of the main theories from the democratization literature. Different types of data are examined—case studies and other documentary evidence, interviews and observation. Following an abductive approach, in addition to examining the veracity of existing theory, each chapter is also used to build an explanation of how democracy is practiced in small states. Specifically, we highlight how small state politics is shaped by personalization and informal politics, rather than formal institutional design.


2021 ◽  
Vol 7 (3) ◽  
pp. 38
Author(s):  
Alexandra Korotaeva ◽  
Danzan Mansorunov ◽  
Natalya Apanovich ◽  
Anna Kuzevanova ◽  
Alexander Karpukhin

Neuroendocrine neoplasms (NEN) are infrequent malignant tumors of a neuroendocrine nature that arise in various organs. They occur most frequently in the lungs, intestines, stomach and pancreas. Molecular diagnostics and prognosis of NEN development are highly relevant. The role of clinical biomarkers can be played by microRNAs (miRNAs). This work is devoted to the analysis of data on miRNA expression in NENs. For the first time, a search for specificity or a community of their functional characteristics in different types of NEN was carried out. Their properties as biomarkers were also analyzed. To date, more than 100 miRNAs have been characterized as differentially expressed and significant for the development of NEN tumors. Only about 10% of the studied miRNAs are expressed in several types of NEN; differential expression of the remaining 90% was found only in tumors of specific localizations. A significant number of miRNAs have been identified as potential biomarkers. However, only a few miRNAs have values that characterized their quality as markers. The analysis demonstrates the predominant specific expression of miRNA in each studied type of NEN. This indicates that miRNA’s functional features are predominantly influenced by the tissue in which they are formed.


Author(s):  
Sandip Moi ◽  
Suvankar Biswas ◽  
Smita Pal(Sarkar)

AbstractIn this article, some properties of neutrosophic derivative and neutrosophic numbers have been presented. This properties have been used to develop the neutrosophic differential calculus. By considering different types of first- and second-order derivatives, different kind of systems of derivatives have been developed. This is the first time where a second-order neutrosophic boundary-value problem has been introduced with different types of first- and second-order derivatives. Some numerical examples have been examined to explain different systems of neutrosophic differential equation.


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1729
Author(s):  
Patrizio Raffa

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.


2021 ◽  
Vol 11 (15) ◽  
pp. 6946
Author(s):  
Bartłomiej Podsiadły ◽  
Andrzej Skalski ◽  
Wiktor Rozpiórski ◽  
Marcin Słoma

In this paper, we are focusing on comparing results obtained for polymer elements manufactured with injection molding and additive manufacturing techniques. The analysis was performed for fused deposition modeling (FDM) and single screw injection molding with regards to the standards used in thermoplastics processing technology. We argue that the cross-section structure of the sample obtained via FDM is the key factor in the fabrication of high-strength components and that the dimensions of the samples have a strong influence on the mechanical properties. Large cross-section samples, 4 × 10 mm2, with three perimeter layers and 50% infill, have lower mechanical strength than injection molded reference samples—less than 60% of the strength. However, if we reduce the cross-section dimensions down to 2 × 4 mm2, the samples will be more durable, reaching up to 110% of the tensile strength observed for the injection molded samples. In the case of large cross-section samples, strength increases with the number of contour layers, leading to an increase of up to 97% of the tensile strength value for 11 perimeter layer samples. The mechanical strength of the printed components can also be improved by using lower values of the thickness of the deposited layers.


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