Adduct Rubbers: A Versatile New Family of Elastomers

1958 ◽  
Vol 31 (2) ◽  
pp. 213-243 ◽  
Author(s):  
R. M. Pierson ◽  
W. E. Gibbs ◽  
G. E. Meyer ◽  
F. J. Naples ◽  
W. M. Saltman ◽  
...  
Keyword(s):  
Methyl Mercaptan ◽  
Double Bonds ◽  
New Family ◽  
Wide Range ◽  
Aging Properties ◽  
Base Polymer ◽  
Free Radical Addition ◽  
Better Than ◽  
Acrylonitrile Copolymers ◽  
Ozone Resistance

Abstract A versatile family of elastomers has been prepared by free radical addition of aliphatic mercaptans to the double bonds of diene polymers. High saturation levels were readily achieved without degradation of the basic polymer chain. The technology is similar to ordinary emulsion polymerization. By varying the nature of the base polymer, the mercaptan used, and the extent of saturation, a wide range of compositions and of physical properties were attained in the adducts. In general, resistance to aging, ozone attack, heat, solvent swelling, and to permeation by gases increased with increasing extent of saturation. Outstanding performance in these qualities was achieved by adducts of polymers whose double bonds had been over 90 per cent saturated. A highly saturated methyl mercaptan adduct of polybutadiene showed (1) stress-strain and air aging properties at 400° and 500° F better than commercially available ethylacrylate copolymers and various semicommercial heat resistant elastomers; (2) permeability resistance equivalent to butyl; (3) solvent swell intermediate between neoprene and medium nitrile content butadiene-acrylonitrile rubbers, with a Tg below −30° C; (4) ozone resistance comparable to the better commercially available saturated rubbers. Increased solvent resistance was obtained by preparing adducts of the appropriate butadiene-acrylonitrile copolymers. Adducts with saturation levels up to about 85 per cent could be cured by the same procedures used for the base polymers. Activated or butyl-type curing systems were required for higher saturation levels. The relative rates at which aliphatic mercaptans add to the several types of double bonds present in emulsion diene polymers have been examined in a preliminary way.

Ordering and aging properties of systems with dependent components governed by the Archimedean copula

2021 ◽  
pp. 1-28
Author(s):  
Tanmay Sahoo ◽  
Nil Kamal Hazra
Keyword(s):  
Stochastic Orders ◽  
Archimedean Copulas ◽  
Stochastic Comparisons ◽  
Dependency Structure ◽  
Distributed Components ◽  
Wide Range ◽  
The Family ◽  
Aging Properties ◽  
Dependency Structures ◽  
Better Than

Abstract Copula is one of the widely used techniques to describe the dependency structure between components of a system. Among all existing copulas, the family of Archimedean copulas is the popular one due to its wide range of capturing the dependency structures. In this paper, we consider the systems that are formed by dependent and identically distributed components, where the dependency structures are described by Archimedean copulas. We study some stochastic comparisons results for series, parallel, and general $r$ -out-of- $n$ systems. Furthermore, we investigate whether a system of used components performs better than a used system with respect to different stochastic orders. Furthermore, some aging properties of these systems have been studied. Finally, some numerical examples are given to illustrate the proposed results.

Research of the activity and viability of spermatozoa at different concentrations and proportions of diluents after incubation

2020 ◽  
pp. 88-95
Author(s):  
Svitlana Lobchenko ◽  
Tetiana Husar ◽  
Viktor Lobchenko
Keyword(s):  
Plasma Concentration ◽  
Incubation Time ◽  
Coefficient Of Variation ◽  
Incubation Medium ◽  
Wide Range ◽  
Series Of Experiments ◽  
The Subject ◽  
Boar Spermatozoa ◽  
Native Plasma ◽  
Better Than

The results of studies of the viability of spermatozoa with different incubation time at different concentrations and using different diluents are highlighted in the article. (Un) concentrated spermatozoa were diluented: 1) with their native plasma; 2) medium 199; 3) a mixture of equal volumes of plasma and medium 199. The experiment was designed to generate experimental samples with spermatozoa concentrations prepared according to the method, namely: 0.2; 0.1; 0.05; 0.025 billion / ml. The sperm was evaluated after 2, 4, 6 and 8 hours. The perspective of such a study is significant and makes it possible to research various aspects of the subject in a wide range. In this regard, a series of experiments were conducted in this area. The data obtained are statistically processed and allow us to highlight the results that relate to each stage of the study. In particular, in this article it was found out some regularities between the viability of sperm, the type of diluent and the rate of rarefaction, as evidenced by the data presented in the tables. As a result of sperm incubation, the viability of spermatozoa remains at least the highest trend when sperm are diluted to a concentration of 0.1 billion / ml, regardless of the type of diluent used. To maintain the viability of sperm using this concentration of medium 199 is not better than its native plasma, and its mixture with an equal volume of plasma through any length of time incubation of such sperm. Most often it is at this concentration of sperm that their viability is characterized by the lowest coefficient of variation, regardless of the type of diluent used, which may indicate the greatest stability of the result under these conditions. The viability of spermatozoa with a concentration of 0.1 billion / ml is statistically significantly reduced only after 6 or even 8 hours of incubation. If the sperm are incubated for only 2 hours, regardless of the type of diluent used, the sperm concentrations tested do not affect the viability of the sperm. Key words: boar, spermatozoa, sperm plasma, concentration, incubation, medium 199, activity, viability, rarefaction.

Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

1996 ◽  
Vol 118 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Chuen-Huei Liou ◽  
Hsiang Hsi Lin ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Spur Gear ◽  
Tooth Size ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Wide Range ◽  
Gear Contact ◽  
Center Distance ◽  
Selection Of ◽  
Better Than

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

scholarly journals Cache-efficient sweeping-based interval joins for extended Allen relation predicates

2021 ◽  
Author(s):  
Danila Piatov ◽  
Sven Helmer ◽  
Anton Dignös ◽  
Fabio Persia
Keyword(s):  
Data Structure ◽  
Experimental Evaluation ◽  
State Of The Art ◽  
Temporal Databases ◽  
Access Method ◽  
Wide Range ◽  
Interval Relation ◽  
Cache Efficient ◽  
Join Algorithms ◽  
Better Than

AbstractWe develop a family of efficient plane-sweeping interval join algorithms for evaluating a wide range of interval predicates such as Allen’s relationships and parameterized relationships. Our technique is based on a framework, components of which can be flexibly combined in different manners to support the required interval relation. In temporal databases, our algorithms can exploit a well-known and flexible access method, the Timeline Index, thus expanding the set of operations it supports even further. Additionally, employing a compact data structure, the gapless hash map, we utilize the CPU cache efficiently. In an experimental evaluation, we show that our approach is several times faster and scales better than state-of-the-art techniques, while being much better suited for real-time event processing.

Triazole, Benzotriazole, and Naphthotriazole as Corrosion Inhibitors for Brass

CORROSION ◽  
1976 ◽  
Vol 32 (10) ◽  
pp. 414-417 ◽  
Author(s):  
R. WALKER
Keyword(s):  
Corrosion Inhibitors ◽  
Lower Cost ◽  
Solution Ph ◽  
Inhibitor Efficiency ◽  
Wide Range ◽  
Better Than

Abstract The use of triazole, benzotriazole, and naphthotriazole as corrosion inhibitors for brass is briefly reviewed. The corrosion of 70/30 brass immersed in a wide range of solutions is reported both with and without the inhibitors. The inhibitor efficiency of benzotriazole is given as a function of the solution pH and the concentration used. Triazole was only effective in mildly corrosive solutions and benzotriazole and naphthotriazole were much better. Generally naphthotriazole was better than benzotriazole but is much more expensive and a higher concentration of benzotriazole can give the same protection as naphthotriazole at a much lower cost.

Poisson mixtures

1995 ◽  
Vol 1 (2) ◽  
pp. 163-190 ◽  
Author(s):  
Kenneth W. Church ◽  
William A. Gale
Keyword(s):  
Negative Binomial ◽  
Probability Distributions ◽  
Hidden Variables ◽  
Heterogeneous Structure ◽  
Text Compression ◽  
Inverse Document Frequency ◽  
Poisson Mixtures ◽  
Document Frequency ◽  
Wide Range ◽  
Better Than

AbstractShannon (1948) showed that a wide range of practical problems can be reduced to the problem of estimating probability distributions of words and ngrams in text. It has become standard practice in text compression, speech recognition, information retrieval and many other applications of Shannon's theory to introduce a “bag-of-words” assumption. But obviously, word rates vary from genre to genre, author to author, topic to topic, document to document, section to section, and paragraph to paragraph. The proposed Poisson mixture captures much of this heterogeneous structure by allowing the Poisson parameter θ to vary over documents subject to a density function φ. φ is intended to capture dependencies on hidden variables such genre, author, topic, etc. (The Negative Binomial is a well-known special case where φ is a Г distribution.) Poisson mixtures fit the data better than standard Poissons, producing more accurate estimates of the variance over documents (σ2), entropy (H), inverse document frequency (IDF), and adaptation (Pr(x ≥ 2/x ≥ 1)).

scholarly journals 3 per cent-accurate predictions for the clustering of dark matter, haloes, and subhaloes, over a wide range of cosmologies and scales

2020 ◽  
Vol 499 (4) ◽  
pp. 4905-4917
Author(s):  
S Contreras ◽  
R E Angulo ◽  
M Zennaro ◽  
G Aricò ◽  
M Pellejero-Ibañez
Keyword(s):  
Dark Matter ◽  
Spatial Distribution ◽  
Cosmological Parameters ◽  
Galaxy Surveys ◽  
Circular Velocity ◽  
Initial Application ◽  
Wide Range ◽  
Massive Neutrinos ◽  
Dynamical Dark Energy ◽  
Better Than

ABSTRACT Predicting the spatial distribution of objects as a function of cosmology is an essential ingredient for the exploitation of future galaxy surveys. In this paper, we show that a specially designed suite of gravity-only simulations together with cosmology-rescaling algorithms can provide the clustering of dark matter, haloes, and subhaloes with high precision. Specifically, with only three N-body simulations, we obtain the power spectrum of dark matter at z = 0 and 1 to better than 3 per cent precision for essentially all currently viable values of eight cosmological parameters, including massive neutrinos and dynamical dark energy, and over the whole range of scales explored, 0.03 < $k/{h}^{-1}\, {\rm Mpc}^{-1}$ < 5. This precision holds at the same level for mass-selected haloes and for subhaloes selected according to their peak maximum circular velocity. As an initial application of these predictions, we successfully constrain Ωm, σ8, and the scatter in subhalo-abundance-matching employing the projected correlation function of mock SDSS galaxies.

scholarly journals Keep the nest clean: survival advantages of corpse removal in ants

2014 ◽  
Vol 10 (7) ◽  
pp. 20140306 ◽  
Author(s):  
Lise Diez ◽  
Philippe Lejeune ◽  
Claire Detrain
Keyword(s):  
Social Insects ◽  
Survival Advantage ◽  
Social Immunity ◽  
Wide Range ◽  
Nest Maintenance ◽  
Colony Survival ◽  
Better Than

Sociality increases exposure to pathogens. Therefore, social insects have developed a wide range of behavioural defences, known as ‘social immunity’. However, the benefits of these behaviours in terms of colony survival have been scarcely investigated. We tested the survival advantage of prophylaxis, i.e. corpse removal, in ants. Over 50 days, we compared the survival of ants in colonies that were free to remove corpses with those that were restricted in their corpse removal. From Day 8 onwards, the survival of adult workers was significantly higher in colonies that were allowed to remove corpses normally. Overall, larvae survived better than adults, but were slightly affected by the presence of corpses in the nest. When removal was restricted, ants removed as many corpses as they could and moved the remaining corpses away from brood, typically to the nest corners. These results show the importance of nest maintenance and prophylactic behaviour in social insects.

scholarly journals Multiple Sclerosis Recognition by Biorthogonal Wavelet Features and Fitness-Scaled Adaptive Genetic Algorithm

2021 ◽  
Vol 15 ◽  
Author(s):  
Shui-Hua Wang ◽  
Xianwei Jiang ◽  
Yu-Dong Zhang
Keyword(s):  
Multiple Sclerosis ◽  
Genetic Algorithm ◽  
Data Augmentation ◽  
Area Under The Curve ◽  
Adaptive Genetic Algorithm ◽  
Biorthogonal Wavelet ◽  
Wide Range ◽  
Wavelet Features ◽  
The Brain ◽  
Better Than

Aim: Multiple sclerosis (MS) is a disease, which can affect the brain and/or spinal cord, leading to a wide range of potential symptoms. This method aims to propose a novel MS recognition method.Methods: First, the bior4.4 wavelet is used to extract multiscale coefficients. Second, three types of biorthogonal wavelet features are proposed and calculated. Third, fitness-scaled adaptive genetic algorithm (FAGA)—a combination of standard genetic algorithm, adaptive mechanism, and power-rank fitness scaling—is harnessed as the optimization algorithm. Fourth, multiple-way data augmentation is utilized on the training set under the setting of 10 runs of 10-fold cross-validation. Our method is abbreviated as BWF-FAGA.Results: Our method achieves a sensitivity of 98.00 ± 0.95%, a specificity of 97.78 ± 0.95%, and an accuracy of 97.89 ± 0.94%. The area under the curve of our method is 0.9876.Conclusion: The results show that the proposed BWF-FAGA method is better than 10 state-of-the-art MS recognition methods, including eight artificial intelligence-based methods, and two deep learning-based methods.

scholarly journals Perancangan dan Analisis Perbandingan Implementasi OSPF pada Jaringan IPv4 dan IPv6

2014 ◽  
Vol 2 (1) ◽  
pp. 40
Author(s):  
PAULINE RAHMIATI ◽  
DWI ARYANTA ◽  
TAUFIQ AGUNG PRIYADI
Keyword(s):  
Network Design ◽  
Shortest Path ◽  
Routing Protocol ◽  
Convergence Time ◽  
The Third ◽  
Wide Range ◽  
Packet Tracer ◽  
Maximum Limit ◽  
Better Than

ABSTRAKOSPF (Open Shortest Path First) adalah suatu routing protokol bersifat terbuka dan didukung oleh berbagai perangkat network. IPv4 telah mencapai batas maksimum dalam jumlah alamat sehingga IPv6 merupakan solusi dalam hal tersebut. Seperti IPv4, IPv6 juga sudah mulai diimplementasikan untuk routing protokol OSPF, oleh karena itu pada penelitian ini akan dirancang suatu routing protokol OSPF IPv6 dan sebagai bahan perbandingan akan dibandingkan dengan OSPF IPv4. Software Cisco Packet Tracer 5.3 digunakan untuk mensimulasikan perancangan jaringan yang dibuat. Pada penelitian ini akan dibandingkan 2 buah jaringan berbasis routing protokol OSPF, yaitu OSPF untuk IPv4 dan IPv6. Skenario pertama dilakukan 100 kali dalam 5 kasus untuk mengetahui nilai delay OSPF IPv4 dan OSPF IPv6. Skenario kedua dilakukan pemutusan link dilakukan sebanyak 30 kali, hal yang dilihat dari pengujian ini adalah hasil trace route dari cost yang ada. Skenario ketiga dilakukan dengan mengamati waktu konvergensi dari OSPF IPv4 dan IPv6. Secara keseluruhan nilai delay OSPF IPv6 lebih kecil dibandingkan dengan OSPF IPv4 sebesar 3-6%, Trace route dan nilai cost pada OSPF IPv6 dan OSPF IPv4 sama tetapi nilai delay OSPF IPv6 lebih kecil sebesar 3-6% dan waktu konvergensi OSPF IPv4 bernilai sama dengan OSPF IPv6 yaitu 10 detik.Kata kunci: OSPF, IPv4, Ipv6, delay, konvergensiABSTRACTOSPF (Open Shortest Path First) is a routing protocol that opened and supported by a wide range of network devices. IPv4 has reached the maximum limit on the number of addresses that IPv6 are a solution in this case. Same as IPv4, IPv6 also has begun to be implemented for the OSPF routing protocol, therefore this study wiould design an IPv6 OSPF routing protocol and as a comparison will be compared to IPv4 OSPF. Cisco Packet Tracer 5.3 software was used to simulate the made network design. This research would compare two pieces of network-based routing protocol OSPF, OSPF for IPv4 and IPv6. The first scenario was done 100 times in of 5 cases to determine the value of delay OSPF OSPF IPv4 and IPv6. The second scenario was carried out link terminations 30 times, it was seen from the tests was the result of trace route from the existing cost. The third scenario was done by observed at the convergence time of OSPF IPv4 and IPv6. The overall delay value OSPF IPv6 better than IPv4 OSPF by 3-6%, the trace route and the OSPF cost value of IPv6 and IPv4 OSPF were same but delay OSPF IPv6 was better 3-6% and convergence time was the same as IPv4 OSPF OSPF IPv6 as 10 seconds.Keywords: OSPF, IPv4, IPv6, delay, convergence

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