scholarly journals Poly(phenylene methylene)-Based Coatings for Corrosion Protection: Replacement of Additives by Use of Copolymers

2019 ◽  
Vol 9 (17) ◽  
pp. 3551 ◽  
Author(s):  
D’Elia ◽  
Magni ◽  
Trasatti ◽  
Schweizer ◽  
Niederberger ◽  
...  
Keyword(s):  
Corrosion Protection ◽  
Electrochemical Corrosion ◽  
Side Chains ◽  
Hydrophobic Coating ◽  
Corrosion Studies ◽  
Proper Design ◽  
Common Problems ◽  
Hydrocarbon Polymer ◽  
Protection Of The Metal

Poly(phenylene methylene) (PPM) is a thermally stable, hydrophobic, fluorescent hydrocarbon polymer. Recently, blended PPM has been proposed as a valuable anti-corrosion coating material, and, in particular, rheological additives such as external plasticizers resulted crucial to prevent crack formation. Accordingly, to avoid common problems related to the use of external plasticizers, the development of PPM-related copolymer-based coatings containing n-octyloxy side chains and their anti-corrosion behavior were explored in this study. The aluminum alloy AA2024, widely employed for corrosion studies, was selected as a substrate, covered with a thin layer of a polybenzylsiloxane in order to improve adhesion between the underlying hydrophilic substrate and the top hydrophobic coating. Gratifyingly, coatings with those copolymers were free of bubbles and cracks. The n-octyloxy side-chains may be regarded to adopt the role of a bound plasticizer, as the glass transition temperature of the copolymers decreases with increasing content of alkoxy side-chains. Electrochemical corrosion tests on PPM-substituted coatings exhibited good corrosion protection of the metal surface towards a naturally aerated near-neutrally 3.5% wt.% NaCl neutral solution, providing comparable results to blended PPM formulations, previously reported. Hence, the application of rheological additives can be avoided by use of proper design copolymers.

Heparan sulfate side chains have a critical role in the inhibitory effects of perlecan on vascular smooth muscle cell response to arterial injury

2014 ◽  
Vol 307 (3) ◽  
pp. H337-H345 ◽  
Author(s):  
Lara Gotha ◽  
Sang Yup Lim ◽  
Azriel B. Osherov ◽  
Rafael Wolff ◽  
Beiping Qiang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Critical Role ◽  
Arterial Injury ◽  
Side Chains ◽  
Wild Type ◽  
Injury Response ◽  
Migratory Response

Perlecan is a proteoglycan composed of a 470-kDa core protein linked to three heparan sulfate (HS) glycosaminoglycan chains. The intact proteoglycan inhibits the smooth muscle cell (SMC) response to vascular injury. Hspg2Δ3/Δ3 (MΔ3/Δ3) mice produce a mutant perlecan lacking the HS side chains. The objective of this study was to determine differences between these two types of perlecan in modifying SMC activities to the arterial injury response, in order to define the specific role of the HS side chains. In vitro proliferative and migratory activities were compared in SMC isolated from MΔ3/Δ3 and wild-type mice. Proliferation of MΔ3/Δ3 SMC was 1.5× greater than in wild type ( P < 0.001), increased by addition of growth factors, and showed a 42% greater migratory response than wild-type cells to PDGF-BB ( P < 0.001). In MΔ3/Δ3 SMC adhesion to fibronectin, and collagen types I and IV was significantly greater than wild type. Addition of DRL-12582, an inducer of perlecan expression, decreased proliferation and migratory response to PDGF-BB stimulation in wild-type SMC compared with MΔ3/Δ3. In an in vivo carotid artery wire injury model, the medial thickness, medial area/lumen ratio, and macrophage infiltration were significantly increased in the MΔ3/Δ3 mice, indicating a prominent role of the HS side chain in limiting vascular injury response. Mutant perlecan that lacks HS side chains had a marked reduction in the inhibition of in vitro SMC function and the in vivo arterial response to injury, indicating the critical role of HS side chains in perlecan function in the vessel wall.

scholarly journals On the Role of Trigger Signal Spreading Velocity for Efficient Self-Healing Coatings for Corrosion Protection

2018 ◽  
Vol 165 (16) ◽  
pp. C1017-C1027 ◽  
Author(s):  
Matthias Uebel ◽  
Loïc Exbrayat ◽  
Martin Rabe ◽  
The Hai Tran ◽  
Daniel Crespy ◽  
...  
Keyword(s):  
Corrosion Protection ◽  
Self Healing ◽  
Spreading Velocity ◽  
Trigger Signal

An Automatic Polarization Apparatus for Electrochemical Corrosion Studies

CORROSION ◽  
1969 ◽  
Vol 25 (12) ◽  
pp. 515-519 ◽  
Author(s):  
W. D. HENRY ◽  
B. E. WILDE
Keyword(s):  
Cathodic Polarization ◽  
Reference Electrode ◽  
Electrochemical Corrosion ◽  
304 Stainless Steel ◽  
Constant Current ◽  
Voltage Source ◽  
Potential Range ◽  
Alloy Development ◽  
Corrosion Studies ◽  
Potentiodynamic Anodic Polarization

Abstract Statistical alloy development programs in which electrochemical screening techniques are used require facilities to produce precision polarization data. Conventional equipment and techniques presently available for such programs are not entirely satisfactory. Therefore, modifications were made to readily available commercial equipment to significantly improve the attainable sensitivity and reproducibility. This paper describes in detail the procedures necessary to produce an apparatus that automatically measures and records anodic and cathodic polarization curves over an applied potential range of ±2.0 volts. Traverse rates between 2 × 10−3 and 3 × 104 volts per hour are attainable and can be used to polarize electrodes through zero volts (with respect to reference electrode) without the necessity of manual switching. A special mode switch is described in detail with which the basic electronic potentiostat can be used as a constant current or constant voltage source by manual selection. The results obtained from three typical polarization experiments: (1) potentiodynamic anodic polarization, (2) galvanodynamic cathodic polarization, and (3) galvanodynamic linear polarization of AISI Type 304 stainless steel in hydrogen saturated 1N H2SO4 at 25 C (77 F), showed the performance of the apparatus to be equal to or superior to that of conventional manual procedures.

Electronic Transport via Homopeptides: The Role of Side Chains and Secondary Structure

2015 ◽  
Vol 137 (30) ◽  
pp. 9617-9626 ◽  
Author(s):  
Lior Sepunaru ◽  
Sivan Refaely-Abramson ◽  
Robert Lovrinčić ◽  
Yulian Gavrilov ◽  
Piyush Agrawal ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Electronic Transport ◽  
Side Chains

scholarly journals Role of Restored Underwater Images in Underwater Imaging Applications

2021 ◽  
Vol 4 (4) ◽  
pp. 96
Author(s):  
Jarina Raihan A ◽  
Pg Emeroylariffion Abas ◽  
Liyanage C De Silva
Keyword(s):  
Machine Learning ◽  
Image Classification ◽  
Feature Detection ◽  
Sea Water ◽  
Learning Algorithm ◽  
Underwater Imaging ◽  
Underwater Image ◽  
Common Problems ◽  
Restoration Method

Underwater images are extremely sensitive to distortion occurring in an aquatic underwater environment, with absorption, scattering, polarization, diffraction and low natural light penetration representing common problems caused by sea water. Because of these degradation of quality, effectiveness of the acquired images for underwater applications may be limited. An effective method of restoring underwater images has been demonstrated, by considering the wavelengths of red, blue, and green lights, attenuation and backscattering coefficients. The results from the underwater restoration method have been applied to various underwater applications; particularly, edge detection, Speeded Up Robust Feature detection, and image classification that uses machine learning. It has been shown that more edges and more SURF points can be detected as a result of using the method. Applying the method to restore underwater images in image classification tasks on underwater image datasets gives accuracy of up to 89% using a simple machine-learning algorithm. These results are significant as it demonstrates that the restoration method can be implemented on underwater system for various purposes.

scholarly journals The Impact of Common Problems between the Sectors of Industry and Capital and Ways of their Solutions in the Russian Federation: أثر المشاكل المُشتركة بين قِطاعات الصِناعة ورؤوس الأموال وطُرُق حُلولها في روسيا الإتحادية

2017 ◽  
Vol 1 (5) ◽  
Author(s):  
Nemer Louay Badwan
Keyword(s):  
Financial Market ◽  
Success Factors ◽  
Investment Projects ◽  
Industrial Sectors ◽  
National Economic ◽  
Capital Financing ◽  
Common Problems ◽  
Industry Sectors ◽  
The Impact

This study summarizes the impact of common problems between capital and industry sectors and aims to find solutions to these problems to reduce them or to reduce them. It also clarifies the resemblance and comparison of technology to the sectors of industry and capital in Russian Russia. Russia's total over the previous years, and show what happened in the Russian financial market following the withdrawal of many capital and investors from within Russia to abroad, and also shows us this study also the rotational nature of capital in Russia, as this study shows some of its objectives as a most important explanation The capital and industry sectors, their success factors and competitiveness in their application. It also shows the impact of capital financing on industries, clarifying the role of capital finance in various investment projects and in different sectors of industry, and summarizes the scientific and practical concept of capital and industry sectors. And the process, and this can be seen through analytical, graphical and statistical tables within the Russian market in terms of products, profits and losses of the Russian industries by percentages, and the exposure of some Russian investments within Russia, As well as some of the dynamics of consumption within Russia in terms of expenditures, exports, imports and expenditures, and the structure of small and medium-sized enterprises in percentages in terms of production and consumption In the various sectors of Russian industry. The study also summarizes the role of the Russian financial market in the national economic activity and the ratios of fixed assets and the total amounts invested and taxes imposed on them. The study also examined the financial and industrial activities of most of the industrial sectors in Russia and their impact on the economic situation inside the country.

scholarly journals Uncovering the Role of Key Active Site Side Chains in Catalysis: An Extended Brønsted Relationship for Substrate Deprotonation Catalysed by Wild-Type and Variants of Triosephosphate Isomerase

2019 ◽  
Author(s):  
Yashraj S. Kulkarni ◽  
Tina L. Amyes ◽  
John Richard ◽  
Shina Caroline Lynn Kamerlin
Keyword(s):  
Active Site ◽  
Triosephosphate Isomerase ◽  
Valence Bond ◽  
Side Chains ◽  
Wild Type ◽  
Empirical Valence Bond

Manuscript and supporting information outlining an analysis of an extended Brønsted relationship obtained from empirical valence bond simulations of substrate deprotonation catalyzed by wild-type and mutant variants of triosephosphate isomerase.

scholarly journals Free Energy Landscape and Rate Estimation of the Aromatic Ring Flips in Basic Pancreatic Trypsin Inhibitor Using Metadynamics

2021 ◽  
Author(s):  
Pär Söderhjelm ◽  
Mandar Kulkarni
Keyword(s):  
Free Energy ◽  
Trypsin Inhibitor ◽  
Side Chain ◽  
Side Chains ◽  
Aromatic Residues ◽  
Basic Pancreatic Trypsin Inhibitor ◽  
Pancreatic Trypsin Inhibitor ◽  
Energy Surfaces ◽  
Aromatic Side Chains

Aromatic side-chains (phenylalanine and tyrosine) of a protein flip by 180° around the Cβ-Cγ axis (χ2 dihedral of side-chain) producing two symmetry-equivalent states. The ring-flip dynamics act as an NMR probe to understand local conformational fluctuations. Ring-flips are categorized as slow (ms onwards) or fast (ns to near ms) based on timescales accessible to NMR experiments. In this study, we investigated the ability of the infrequent metadynamics approach to discriminate between slow and fast ring-flips for eight individual aromatic side-chains (F4, Y10, Y21, F22, Y23, F33, Y35, F45) of basic pancreatic trypsin inhibitor (BPTI). Well-tempered metadynamics simulations were performed to observe ring-flipping free energy surfaces for all eight aromatic residues. The results indicate that χ2 as a standalone collective variable (CV) is not sufficient to classify fast and slow ring-flips. Most of the residues needed χ1 (N−Cχα) as a complementary CV, indicating the importance of librational motions in ring-flips. Multiple pathways and mechanisms were observed for residues F4, Y10, and F22. Recrossing events are observed for residues F22 and F33, indicating a possible role of friction effects in the ring-flipping. The results demonstrate the successful application of the metadynamics based approach to estimate ring-flip rates of aromatic residues in BPTI and identify certain limitations of the approach.

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