Reinforcement of Polymers. I. Tear Resistance of Filled Mixes and Adhesion of Elastomer to Filler as a Function of Duration and Temperature of Elastomer and Filler Contact

1968 ◽  
Vol 41 (3) ◽  
pp. 601-607
Author(s):  
V. G. Raevskii ◽  
S. M. Yagnyatinskaya ◽  
S. N. Episeeva ◽  
S. S. Voyutskii

Abstract In accordance with the concepts being developed by the authors of the present paper, the influence of fillers on the properties of filled systems is determined by adhesion of the polymer to the filler. There are indications of the significance of this factor in many papers dealing with the study of reinforcement. However, they do not advance adhesion as a basic factor which determines reinforcement. This has become possible after the development of a procedure for the evaluation of adhesion of polymers to powdered fillers. This paper lists experimental data on the correlation between the duration and temperature of contact of the elastomer with filler particles on the tear resistance of filled mixes, on one hand, and the time and temperature dependence of the adhesion of the system components to one another, on the other. The selection of tear resistance as a characteristic of the physicomechanical properties of the system is governed by the fact that failure starts, as a rule, from a random local defect. Most frequently this is a small cut or surface crack. For this reason, the assertion of a number of researchers that the operating properties of products are more fully characterized by tear resistance rather than by tensile strength is fully acceptable. Besides, tearing is the most general type of destruction of materials, inasmuch as it takes place during rupture as well as during wear.

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3487
Author(s):  
Walid Abotbina ◽  
S. M. Sapuan ◽  
M. T. H. Sultan ◽  
M. F. M. Alkbir ◽  
R. A. Ilyas

This work aims to develop cornstarch (CS) based films using fructose (F), glycerol (G), and their combination (FG) as plasticizers with different ratios for food packaging applications. The findings showed that F-plasticized film had the lowest moisture content, highest crystallinity among all films, and exhibited the highest tensile strength and thermostability. In contrast, G-plasticized films showed the lowest density and water absorption with less crystallinity compared to the control and the other plasticized film. In addition, SEM results indicated that FG-plasticized films had a relatively smoother and more coherent surface among the tested films. The findings have also shown that varying the concentration of the plasticizers significantly affected the different properties of the plasticized films. Therefore, the selection of a suitable plasticizer at an appropriate concentration may significantly optimize film properties to promote the utilization of CS films for food packaging applications.


2020 ◽  
Vol 54 (30) ◽  
pp. 4853-4873 ◽  
Author(s):  
Lucas L Vignoli ◽  
Marcelo A Savi ◽  
Pedro MCL Pacheco ◽  
Alexander L Kalamkarov

The analysis of several micromechanical models for estimating strength of composite laminae is presented. Longitudinal tensile, compressive and in-plane onset shear strengths are analytically estimated and compared with experimental data available in the literature. The tensile longitudinal load predominantly induces rupture of fibers. On the other hand, the compressive strength is highly influenced by fiber misalignment, inducing a wide range of failure mechanisms. The material response to in-plane shear presents a strong nonlinear response. The estimation of longitudinal tensile strength based on the rule of mixture approaches is compared with 27 experimental data. A novel improvement is proposed assuming that in situ strength of fiber is smaller than fiber strength measured individually due to manufacturing induced damage. For the in-plane shear, 6 models are compared with 10 experimental stress-strain curves, including a novel closed-form expression based on the concentric cylinders model. Finally, for the longitudinal compressive strength, 8 micromechanical models, including a novel model to estimate misalignment effect in fiber crushing, are compared with 61 experimental data are analyzed. Results indicate that the minimal average error for the longitudinal tensile strength is 12.4% while for the compressive strength it is 15%. For the shear strength, the closest prediction depends on the strength definition and the proposed damage onset strength presents the best predictions. In general, the newly proposed models present the best estimations compared with the other models.


2021 ◽  
Vol 77 (1) ◽  
pp. 1-13
Author(s):  
Md. Shamsuzzaman ◽  
Ziad Abdul Awal ◽  
Dip Das

This paper investigates the changes in the properties of denim garments with respect to laser intensities of different DPI and Pixel Time. The laser added value to denim garments can fade the outer surface and the yarn portion significantly. In this research, DPI 20 and 25 along with Pixel Time 100, 150 and 200 were applied on samples to investigate the fabric weight, absorbency, crease recovery, tear resistance, tensile strength, pilling and abrasion resistance. For each of the cases, increased DPI and Pixel Time had much greater impact than other parameters on the denim garment samples. After treatment, the fabric sample indicated around 10-30% in weight reduction. The absorbency property of the sample on the other hand showed that higher DPI and Pixel Time required less time to absorb the water on the fabric surface. Furthermore, fabric crease recovery property reduced sharply where maximum 33% crease could not recover after laser exposure. For both tear resistance and tensile strength, especially warp way direction, property reduced more compared to weft way direction due to higher fading effects. After 12,000 cycles, both pilling and abrasion resistance property demonstrated significant reduction for higher laser intensities.


Author(s):  
Raquel Cristine Kuhn ◽  
Francisco Maugeri Filho

This work aimed to describe the adsorption of sugars (glucose, fructose, sucrose and fructooligosaccharides) employing different adsorbents (celite, active carbon and NaX zeolite) by means of isothermal models. At the adsorbent selection step, the active carbon exhibited a higher affinity for the adsorption of fructooligosaccharides. On the other hand, the adsorbents NaX zeolite and celite presented the highest adsorption stability with glucose, giving values of 1.496 g glucose/g zeolite and 1.35 g glucose/g celite. Therefore, zeolite and celite were the adsorbents selected for the determination of isothermal kinetics and it was shown that the linear model (q*= k.C*) provided the best fit for the experimental data. The temperatures studied were 30, 40 and 50 °C, and the 50°C resulted in the highest partition coefficient (k) for glucose on celite, indicating that higher temperatures benefit sugar adsorption.


2021 ◽  
Vol 2090 (1) ◽  
pp. 012130
Author(s):  
A Plachá ◽  
P. Ruliński ◽  
L. Rybakiewicz

Abstract The choice of material, type of braid and rope parameters are a broad issue of great importance in the designing process. An equally important issue is the proper selection of knot type used for attaching the rope to the other elements of a structure, as this is a critical point accumulating major stresses. Inappropriate tying of a rope may decrease its tensile strength by over 50%; therefore, it is an important issue in terms of structural strength. This article investigates different tying configurations of the same rope and shows the influence of knot types on rope static tensile strength.


1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.


Author(s):  
Zimmatul Liviana

The research grammatical interference in a collection ofshort stories Biarkan Aku Memula iwork Nurul F. Hudaisa collection ofshort storiesset in the back that Is start work Let Nurul F. Huda contains many grammatical interference.The problem of this   study were(1)how   the various morphologi calinterference containedin   a   collection of short stories Biarkan Aku Memulai work Nurul F. Huda. (2)how the various syntactic interference contained in a collection of short stories Biarkan Aku Memulai work Nurul F. Huda. The purposeof this studyis to describe the morphological and         Syntactic interference contained in a collection of short stories Biarkan Aku Memulai work Nurul F. Huda. Sociolinguistics is the study of language variation and use in society. Interference is the event of the use of language elements of one into the other language elements that occur in the speakers themselves. This research uses descriptive qualitative method because to describe the actual realityin order to obtainan accurateand objective. Qualitative descriptive methods were used to analyzethe elements ofa word orphrase that incorporated elements of other languages with the analysis and description of the formulation of the problem is the answer. Data collection techniques using observation techniques, the determination ofthe object of research, the selection of short stories.Based on the analysis of the data in this study can be found that there are six forms of interference morphology, namely (1) the prefix nasal N-sound, (2) the addition of the suffix, (3) the exchange prefix, (4) exchange suffixes, (5) exchange konfiks, (6) removal affixes. While the syntactic interference only on the words and phrases in a sentence. The results of the study it can be concluded that the interference morphology more common than syntactic interference.


Author(s):  
Yochai Benkler ◽  
Robert Faris ◽  
Hal Roberts

This chapter presents a model of the interaction of media outlets, politicians, and the public with an emphasis on the tension between truth-seeking and narratives that confirm partisan identities. This model is used to describe the emergence and mechanics of an insular media ecosystem and how two fundamentally different media ecosystems can coexist. In one, false narratives that reinforce partisan identity not only flourish, but crowd-out true narratives even when these are presented by leading insiders. In the other, false narratives are tested, confronted, and contained by diverse outlets and actors operating in a truth-oriented norms dynamic. Two case studies are analyzed: the first focuses on false reporting on a selection of television networks; the second looks at parallel but politically divergent false rumors—an allegation that Donald Trump raped a 13-yearold and allegations tying Hillary Clinton to pedophilia—and tracks the amplification and resistance these stories faced.


Author(s):  
D. Josephine Selvarani Ruth

AbstractNickel Titanium Naval Ordinance Laboratory (NiTiNOL) is widely called as a shape memory alloy (SMA), a class of nonlinear smart material inherited with the functionally programmed property of varying electrical resistance during the transformation enabling to be positioned as a sensing element. The major challenge to instrument the SMA wires is to suppress the wires’ nonlinearity by proper selection of two important factors. The first factor is influenced by the mechanical biasing element and the other is to identify the sensing current for the sensing device (SMA wires + biasing). This paper focuses on developing SMA wires for sensing in different orientation types and configurations by removing the non-linearity in the system’s output by introducing inverse hysteresis to the wires through the passive mechanical element.


Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3311
Author(s):  
Riccardo Ballarini ◽  
Marco Ghislieri ◽  
Marco Knaflitz ◽  
Valentina Agostini

In motor control studies, the 90% thresholding of variance accounted for (VAF) is the classical way of selecting the number of muscle synergies expressed during a motor task. However, the adoption of an arbitrary cut-off has evident drawbacks. The aim of this work is to describe and validate an algorithm for choosing the optimal number of muscle synergies (ChoOSyn), which can overcome the limitations of VAF-based methods. The proposed algorithm is built considering the following principles: (1) muscle synergies should be highly consistent during the various motor task epochs (i.e., remaining stable in time), (2) muscle synergies should constitute a base with low intra-level similarity (i.e., to obtain information-rich synergies, avoiding redundancy). The algorithm performances were evaluated against traditional approaches (threshold-VAF at 90% and 95%, elbow-VAF and plateau-VAF), using both a simulated dataset and a real dataset of 20 subjects. The performance evaluation was carried out by analyzing muscle synergies extracted from surface electromyographic (sEMG) signals collected during walking tasks lasting 5 min. On the simulated dataset, ChoOSyn showed comparable performances compared to VAF-based methods, while, in the real dataset, it clearly outperformed the other methods, in terms of the fraction of correct classifications, mean error (ME), and root mean square error (RMSE). The proposed approach may be beneficial to standardize the selection of the number of muscle synergies between different research laboratories, independent of arbitrary thresholds.


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