scholarly journals Effect of Alkali Hydroxide on the Properties of PTFE Graphite Bonded Aluminium Titanium Composite Sheet

2020 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Hot Rolling ◽  
Alkali Metals ◽  
Spray Coating ◽  
Alkali Halides ◽  
Hot Water ◽  
Intrinsic Properties ◽  
Polymer Emulsion ◽  
Composite Sheet ◽  
The Stability ◽  
Alkali Hydroxide

This study focused on the effect of some alkali hydroxide on the properties of a composite sheet prepared by power spray coating of clean aluminium-titanium sheets with PTFE/graphite emulsion. The blank sheets were washed with hot water and dried at 80 °C for 5-6 minutes before power spraying of colorless polytetrafluoroethylene PTFE/graphite emulsion in perfluoro kerosene followed by hot-rolling under a pressure of 150-200 KPa at the temperature 50 °C higher than the melting temperature of the PTFE polymer (Du Pont). The obtained sandwich was sintered at 550 °C for a few minutes. Alkali hydroxide was added to the polymer emulsion before spraying. Results showed that temperature and time enhanced the extent of adhesion of the two metals to form a homogeneous composite metal sheet. Alkali hydroxide inclusion deteriorates the stability of the prepared sheet. The alkali effect was because PTFE is inactive material, Incompatible with molten alkali metals and alkali hydroxide. The disability of the alkali hydroxide to be incompatible with the polymer material experienced changes in its intrinsic properties. Alkali halides have insignificant effect. Alkali halides just displayed a filling in material.

scholarly journals Effect of Hot Rolling on the Intrinsic Properties of Aluminium-Titanium Bonded by PTFE/ C -Cyanoacrylate

2021 ◽  
pp. 12-22
Author(s):  
Mahmoud A. Rabah
Keyword(s):  
Hot Rolling ◽  
Linear Thermal Expansion ◽  
Rolling Process ◽  
Oh Radicals ◽  
Intrinsic Properties ◽  
Composite Sheet ◽  
Oxygenated Water ◽  
Soft Metal ◽  
Coated Surfaces ◽  
Effect Of Hot Rolling

The concern of this study shows the effect of hot rolling on the properties of a composite sheet prepared from aluminium bonded to titanium metals sandwiching PTFE (Du Pont)/graphite emulsion in perfluoro kerosene. The metals were soaked in hot oxygenated water and dried at 80 °C for 5 - 10 minutes to create a thin film of oxide. The metals were bonded with cyanoacrylate blended to the polymer emulsion that applied to the oxidized surface of the clean metals. Two coated surfaces sandwich the polytetrafluoroethylene (PTFE)/graphite emulsion followed by ‎hot-rolling. The rolling process was matched at 500- 560 °C (≈ 150 °C, over the melting point of the PTFE) under a pressure of 150-200 KPa. The obtained composite sheet was annealed at 550 °C to remove any residual stresses. Results revealed that upon cooling, the mix microphase would separate with the OH radicals on the metal surface and the CF displaced away. The temperature and time of cyanoacrylate application enhanced the extent of adhesion to create a homogeneous composite metal sheet. The effect of the hot rolling conditions was ascribed to the PTFE underactivity and incompatibility. Rolling imparts squeezing of the metals and changes the intrinsic properties. Linear thermal expansion coefficient of the composite sheet confirms partial diffusion of the soft metal in the harder one across the adhesive. The applied technique deforms the PTFE particles without inhibiting the adhesion strength of the cyanoacrylate. The prepared sheet has physical properties that would be suitable for bailiwick and structural ‎application.

scholarly journals Study On Setting Method of Flatness Target Curve of SUNDWIG 20-High Mill Considering Target Crown

2021 ◽  
Author(s):  
Jianliang Sun ◽  
Mingze Yan ◽  
Mingyuan Li ◽  
Tongtong Hao
Keyword(s):  
Control Theory ◽  
Cold Rolling ◽  
Hot Rolling ◽  
New Method ◽  
Discrimination Model ◽  
Flatness Control ◽  
Simulation Results ◽  
The Stability ◽  
And Control

Abstract The flatness target curve is important in the flatness control theory. The accuracy of flatness target curve is an important factor to determine the load of flatness control means and flatness quality. Aiming at the defect that crown of each pass after rolling cannot be controlled quantitatively in the traditional target curve formulation of cold rolling, a new method considering the target crown was proposed. Specifically, the target crown of each pass can be set by combining the total proportional crown change in hot rolling field to each pass and the instability discrimination model in cold rolling field. the total proportional crown change of incoming material and finished product is allocated to each pass, and the instability discrimination model is applied to ensure the stability of the plate. The purpose of new method is to control of the crown of each pass quantitatively, so that the flatness and thickness of plate can meet the production requirements. Taking SUNDWIG 20-high mill and typical rolling products as an example, the simulation results show that, on the basis of ensuring the flatness and obtaining the minimum available crown after rolling, the model can make the flatness and crown meet the production requirements at the same time and control the crown of each pass after rolling quantitatively by setting the target crown of each pass.

scholarly journals Carbonitration of a Tool for Pressing Stainless Steel Pipes

2020 ◽  
Vol 7 (2) ◽  
pp. C17-C21
Author(s):  
I. V. Ivanov ◽  
M. V. Mohylenets ◽  
K. A. Dumenko ◽  
L. Kryvchyk ◽  
T. S. Khokhlova ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Heat Resistance ◽  
Alkali Metals ◽  
Matrix Ring ◽  
High Hardness ◽  
Operating Conditions ◽  
Matrix Rings ◽  
Conventional Heat Treatment ◽  
The Stability

To upgrade the operational stability of the tool at LLC “Karbaz”, Sumy, Ukraine, carbonation of tools and samples for research in melts of salts of cyanates and carbonates of alkali metals at 570–580 °C was carried out to obtain a layer thickness of 0.15–0.25 mm and a hardness of 1000–1150 НV. Tests of the tool in real operating conditions were carried out at the press station at LLC “VO Oscar”, Dnipro, Ukraine. The purpose of the test is to evaluate the feasibility of carbonitriding of thermo-strengthened matrix rings and needle-mandrels to improve their stability, hardness, heat resistance, and endurance. If the stability of matrix rings after conventional heat setting varies around 4–6 presses, the rings additionally subjected to chemical-thermal treatment (carbonitration) demonstrated the stability of 7–9 presses due to higher hardness, heat resistance, the formation of a special structure on the surface due to carbonitration in salt melts cyanates and carbonates. Nitrogen and carbon present in the carbonitrided layer slowed down the processes of transformation of solid solutions and coagulation of carbonitride phases. The high hardness of the carbonitrified layer is maintained up to temperatures above 650 °C. If the stability of the needle-mandrels after conventional heat treatment varies between 50–80 presses, the needles, additionally subjected to chemical-thermal treatment (carbonitration) showed the stability of 100–130 presses due to higher hardness, wear resistance, heat resistance, the formation of a special surface structure due to carbonitration in melts of salts of cyanates and carbonates. Keywords: needle-mandrel, matrix ring, pressing, heat treatment, carbonitration.

scholarly journals Development of Temperature Process Control Method Using Smith Predictor

2019 ◽  
Vol 111 ◽  
pp. 06016
Author(s):  
Nikolajs Bogdanovs ◽  
Romualds Beļinskis ◽  
Ernests Petersons ◽  
Andris Krūmiņš ◽  
Artūrs Brahmanis
Keyword(s):  
Time Delay ◽  
Control Method ◽  
Distributed Delay ◽  
Heating System ◽  
Smith Predictor ◽  
Hot Water ◽  
Test Bed ◽  
Hot Water Supply ◽  
The Stability ◽  
System With Time Delay

The analysis of a problem of development of control systems for objects with big time delay is carried out in this work. For such objects it is difficult to provide high-quality control, because the control is carried on the last status of object’s output. The main setup methods of PID regulators have been examined. Based on this analysis the technique of complete synthesis of the regulator of higher level is given in order to regulate building’s heating system. This work offers a new method of object’s control with distributed delay. As the test bed for the offered structure of control the valve of hot water supply in a heat-node is used. Using the test bed the stability of the system with time delay have been studied, which is controlled by the PID-regulator assisted by Smith Predictor used to compensate the dead time.

scholarly journals Influence of the degree of soil organic matter lability on the calcium carbonate equilibrium of soil water

2010 ◽  
Vol 5 (No. 2) ◽  
pp. 58-68
Author(s):  
S. Kužel ◽  
L. Kolář ◽  
J. Gergel ◽  
J. Peterka ◽  
J. Borová-Batt
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Soil Water ◽  
Saturation Index ◽  
Farmyard Manure ◽  
Hot Water ◽  
Organic Matters ◽  
Langelier Saturation Index ◽  
The Stability ◽  
Carbonate Equilibrium

: In average samples of three sandy-loamy acid Cambisols from a South Bohemian area labile organic matters were determined by the permangate method modified by the dichromate method, and the rate constant of their biochemical oxidation was determined in hot water extracts of the samples. The need of liming was determined by means of 2 methods. In soil solutions of these samples, all values necessary to evaluate their calcium carbonate equilibriums were determined. The soil samples were enriched with 3% of dry matter of two organic materials, farmyard manure and meadow clover meal, and were incubated at 25&deg;C for 180 days under wetting above 50% of their retention water capacity, and after this procedure all analyses were repeated. Both methods were found to increase the need of liming in all three soils: the more labile the organic matter in 3% addition, the higher the need. The meadow clover matter was more labile than the farmyard manure matter. All three methods for the study of soil carbon lability yielded similar results while the potassium permanganate method was more sensitive than the dichromate one. Increases were observed in equilibrium [Cr(H<sub>2</sub>CO<sub>3</sub>* )] and in Langelier saturation index I<sub>s</sub>. This means that soil liming cannot be considered only as an adjustment to the soil acidity and supply of calcium to plants to meet their requirements, but also as a replacement of the spontaneous adjustment to calcium carbonate equilibrium of soil water, for which through mineralisation of labile organic matters in conditions of our experiment about 220 kg CaCO<sub>3</sub> per hectare of land were consumed on condition that it was not necessary to re-establish it. The process of Ca-compound consumption to establish the calcium carbonate equilibrium is controlled exclusively by the degree of mineralising organic matters lability while the influence of soil properties is only marginal. The same results were provided by the comparison of calcium carbonate equilibriums in nine &Scaron;umava brooks of the total watershed area 78 564 km<sup>2</sup> with the degree of lability of organic matters in their sediments in 1986, 2001 and 2004. A reduction in the intensity of agricultural production in 1986&ndash;2004 resulted in an increase in the stability of organic matters in the sediments, in a decrease in I<sub>s</sub>, and in a lower corrosivity of brooks water towards CaCO<sup>3</sup>. However, the quality of soils and their potential soil fertility decreased due to the loss of labile organic matters.

Radiation and thermal effects on polymeric immobilization devices used in patients submitted to radiotherapy

2011 ◽  
Vol 11 (2) ◽  
pp. 101-106
Author(s):  
C. Pereira-Loch ◽  
R. Benavides ◽  
M. Fogliato S. Lima ◽  
B.M. Huerta
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Young’S Modulus ◽  
Thermal Effects ◽  
Young's Modulus ◽  
Thermal Conditions ◽  
Joint Effect ◽  
Hot Water ◽  
Slight Variation ◽  
The Stability

AbstractImmobilization devices in radiotherapy are made of a soft plastic easy to mould when immersed in hot water. Same item is usually used for 6 patients (according to protocol), but at Hospital Sao Jose (HSJ) they have been showing some deformation during the re-utilization process. The latter is the reason for this research where devices were treated with 6 thermal conditions, 6 irradiation procedures and the joint effect of both treatments. DSC, TGA and WAXD indicated devices are made of polycaprolactone (PCL), but no signs of degradation, except a slight variation in crystalinity; however, mechanical properties by means of Young’s modulus steadily increase its values through number of treatments up to a 20%. Activation energy (Ea) obtained by multi-ramps of TGA-Arrhenius evaluated for the most treated samples (6th treatment) indicates that temperature facilitates degradation while irradiation and joint treatments enhance the stability of PCL, apparently by crosslinking.

On the stability of alkali metals in the interlayer spacing of graphite

1990 ◽  
Vol 38 (3) ◽  
pp. 403-406
Author(s):  
H Shioyama ◽  
K Tatsumi ◽  
I Souma
Keyword(s):  
Alkali Metals ◽  
Interlayer Spacing ◽  
The Stability

scholarly journals Development of a Stable TiO2Nanocomposite Self-Cleaning Coating for Outdoor Applications

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
F. Madidi ◽  
G. Momen ◽  
M. Farzaneh
Keyword(s):  
Mechanical Stability ◽  
Low Cost ◽  
Spray Coating ◽  
Dielectric Behavior ◽  
Superhydrophobic Coatings ◽  
Angle Measurements ◽  
Coating Method ◽  
Specific Frequency ◽  
Self Cleaning ◽  
The Stability

A convenient and low-cost approach for the elaboration of a stable superhydrophobic coating is reported, involving the use of TiO2nanoparticles via the spray coating method. This method can be used for preparing self-cleaning superhydrophobic coatings on large areas for different kinds of substrates. The synergistic effect of the micro/nanobinary scale roughness was produced by a multilayer RTV SR/TiO2composite. The influence of the nanofiller concentration in a specific frequency range (40 Hz to 2 MHz) on the dielectric behavior was analyzed as well. It was found that the real relative permittivity (εr′) increases as the nanofiller concentration increases. Superhydrophobic behavior is analyzed by contact angle measurements, scanning electron microscopy (SEM), and profilometer. The stability of the developed coating also has been evaluated in terms of immersion in various aqueous solutions, heating, adhesion, and exposure to UV irradiation, and the results showed good stability against these factors. The coating retained its superhydrophobicity after several days of immersion in solutions of different pH levels (2, 4, 6, and 12) and different conductivities. In addition, they also exhibited exceptional stability against UV radiation and heating, as well as good mechanical stability.

scholarly journals Vulnerable species interactions are important for the stability of mutualistic networks

2019 ◽  
Author(s):  
Benno I. Simmons ◽  
Hannah S. Wauchope ◽  
Tatsuya Amano ◽  
Lynn V. Dicks ◽  
William J. Sutherland ◽  
...  
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Species Interaction ◽  
Interaction Networks ◽  
Ecological Communities ◽  
Ecological Context ◽  
Intrinsic Properties ◽  
Network Stability ◽  
Starting Point ◽  
The Stability

AbstractSpecies are central to ecology and conservation. However, it is the interactions between species that generate the functions on which ecosystems and humans depend. Despite the importance of interactions, we lack an understanding of the risk that their loss poses to ecological communities. Here, we quantify risk as a function of the vulnerability (likelihood of loss) and importance (contribution to network stability in terms of species coexistence) of 4330 mutualistic interactions from 41 empirical pollination and seed dispersal networks across six continents. Remarkably, we find that more vulnerable interactions are also more important: the interactions that contribute most to network stability are those that are most likely to be lost. Furthermore, most interactions tend to have more similar vulnerability and importance across networks than expected by chance, suggesting that vulnerability and importance may be intrinsic properties of interactions, rather than only a function of ecological context. These results provide a starting point for prioritising interactions for conservation in species interaction networks and, in areas lacking network data, could allow interaction properties to be inferred from taxonomy alone.

scholarly journals Home Administration of CVD 103-HgR: A Live Attenuated Oral Cholera Vaccine

2021 ◽  
Vol 104 (4) ◽  
pp. 1232-1240
Author(s):  
R. Paul Duffin ◽  
Michael Delbuono ◽  
Lawrence Chew ◽  
James Johnstone ◽  
Volker Niedan ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Oral Vaccine ◽  
Storage Conditions ◽  
Hot Water ◽  
World Health ◽  
Self Administration ◽  
Health Agencies ◽  
Oral Cholera Vaccine ◽  
The Stability ◽  
User Friendly

ABSTRACTVaccination is a well-established means for prevention and spread of disease in people traveling abroad. Although vaccines to diseases such as cholera are recommended by world health agencies, they are seldom required even when traveling to endemic regions. Consequences of noncompliance can affect traveler’s health and spread diseases to new regions, as occurred in Haiti in 2010 when United Nations peacekeepers from Nepal, where a cholera outbreak was underway, introduced the disease to the region. Steps to increase vaccine recommendation compliance should therefore be an integral part of vaccine development. PXVX0200 contains Center for Vaccine Development 103-HgR live, attenuated recombinant Vibrio cholerae vaccine strain, and is indicated for single-dose immunization against the bacteria that causes cholera. It is supplied as one buffer and one active component packet to be mixed into water and ingested. Administration instructions are designed to be “user friendly” with flexibility for self-administration, thus promoting compliance. Studies to support self-administration were conducted to cover stability of the vaccine outside of normal storage conditions, potency in case of misadministration, and disposal procedures to minimize environmental impact. The principal findings showed that the stability of vaccine was maintained under conditions allowing for transport times and temperature conditions as well as when misadministration errors were made. Finally, the vaccine was effectively neutralized with hot water and soap to prevent bacterial environmental contamination in the event of an accidental spill. The conclusion is that PXVX0200 oral vaccine is stable, easy to formulate and dispose of, and is amenable to self-administration.

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