USE OF MODIFIERS FOR INCREASE OF OPERATIONAL PROPERTIES OF PAINT COATINGS ON THE BASIS OF THE EPOXY FILM-FORMING (review)

2021 ◽  
pp. 63-72
Author(s):  
V.A. Kuznetsova ◽  
◽  
V.V. Yemelyanov ◽  
G.G. Shapovalov ◽  
N.A. Kovrizhkina ◽  
...  
Keyword(s):  
Synthetic Polymers ◽  
Main Attention ◽  
Epoxy Oligomers ◽  
Film Forming ◽  
Long Time ◽  
Paint Coatings ◽  
Physical And Chemical ◽  
Epoxy Paint

Epoxy oligomers are one of the most widespread synthetic polymers who during already enough long time apply to manufacturing of paint and varnish materials. Possessing number of valuable properties, epoxy paint and varnish materials have also shortcomings for which elimination use different receptions, including physical and chemical updatings using different mono- and elastomeric, silicon- and organophosphorous and other connections. The main attention is given to use of different modifiers for improvement of operational properties of anticorrosion paint coatings.

scholarly journals Enzymes Involved in Plastic Degradation

2021 ◽  
pp. 95-110
Author(s):  
S.Z.Z. Cobongela
Keyword(s):  
Polyethylene Terephthalate ◽  
Synthetic Polymers ◽  
Chemical Degradation ◽  
Natural Resistance ◽  
Aquatic Life ◽  
Carbon Backbone ◽  
Catabolic Enzymes ◽  
Plastic Degradation ◽  
Global Increase ◽  
Physical And Chemical

The global increase in production of plastic and accumulation in the environment is becoming a major concern especially to the aquatic life. This is due to the natural resistance of plastic to both physical and chemical degradation. Lack of biodegradability of plastic polymers is linked to, amongst other factors, the mobility of the polymers in the crystalline part of the polyesters as they are responsible for enzyme interaction. There are significantly few catabolic enzymes that are active in breaking down polyesters which are the constituents of plastic. The synthetic polymers widely used in petroleum-based plastics include polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polyurethane (PUR), polystyrene (PS), polyamide (PA) and polyethylene terephthalate (PET) being the ones used mostly. Polymers with heteroatomic backbone such as PET and PUR are easier to degrade than the straight carbon-carbon backbone polymers such as PE, PP, PS and PVC.

Triclinic boron nanosheets high-efficient electrocatalysts for water splitting

2021 ◽  
Author(s):  
Maoping Xu ◽  
Rui Wang ◽  
Kan Bian ◽  
Chuang Hou ◽  
Yaxing Wu ◽  
...  
Keyword(s):  
Active Sites ◽  
Theoretical Calculations ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Energy Storage And Conversion ◽  
High Efficient ◽  
Long Time ◽  
Time Cycle ◽  
Metal Properties ◽  
Physical And Chemical

Abstract Recently, two-dimensional (2D) boron nanosheets have been predicted to exhibit exceptional physical and chemical properties, which is expected to be widely used in advanced electronics, optoelectronic, energy storage and conversion devices. However, the experimental application of 2D boron nanosheets in hydrogen evolution reactiuon (HER) has not been reported. Here, we have grown ultrathin boron nanosheets on tungsten foils via chemical vapor deposition (CVD). The prepared triclinic boron nanosheets are highly crystalline, which perfectly match the structure in the previous theoretical calculations. Notably, the boron nanosheets show excellent HER performance. The Tafel slope is only 64 mV/dec-1 and the nanosheets can maintain good stability under long-time cycle in acidic solution. The improvement of performance is mainly due to the metal properties and a large number of exposed active sites on the boron nanosheets, which is confirmed by first-principle calculations.

scholarly journals Effects of physical and chemical factors on pseudorabies virus activity in vitro

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Lang Gong ◽  
Qiwei Deng ◽  
Runda Xu ◽  
Chihai Ji ◽  
Heng Wang ◽  
...  
Keyword(s):  
Pseudorabies Virus ◽  
Irradiation Time ◽  
Biological Characteristics ◽  
Economic Losses ◽  
Multiple Factors ◽  
Alkaline Environments ◽  
Long Time ◽  
Chemical Factors ◽  
Physical And Chemical

Abstract Background Pseudorabies (PR) is latent and can persist in infected sows for a long time, and thus, convalescent sows can carry the virus throughout life, causing severe economic losses to farmers and posing a tremendous challenge to PR prevention and control. Here, to investigate the biological characteristics of pseudorabies virus (PRV), a variety of physical and chemical factors were analyzed under controlled conditions. Results The results showed that a high ambient temperature and dry environment led to faster virus inactivation. PRV had a certain resistance to weakly acidic or alkaline environments and was rapidly inactivated in strongly acidic or alkaline environments. The effect of ultraviolet (UV) radiation on PRV activity primarily depended on the frequency, intensity, and irradiation time of the UV exposure. Exposure to sunlight inactivated PRV via multiple factors, including temperature, sunlight intensity, UV intensity, and environmental humidity, and any shielding from sunlight strongly lowered the killing effect. Conventional disinfectants had a good disinfection effect on PRV. Conclusions The biological characteristics of different PRV strains are variable. Generally, the activity of PRV is affected by multiple factors, which can show both synergy and antagonism. Real-world conditions should be taken into consideration to guide pork production.

Physical and chemical aspects of the development of overpressuring in sedimentary environments

Clay Minerals ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 425-437 ◽  
Author(s):  
P. L. Hall
Keyword(s):  
Fluid Pressure ◽  
Sediment Thickness ◽  
Volume Changes ◽  
Sedimentary Environments ◽  
Vertical Permeability ◽  
Burial Rate ◽  
Long Time ◽  
Physical And Chemical ◽  
First Time ◽  
Applied Stresses

AbstractFluid pressures in argillaceous sediments depend on, inter alia, mechanical stresses, temperature, diagenetic volume changes and permeability. However, the relative influence of the pressuring mechanisms depends critically upon the long time-scale compliance, C, of the overpressured layer.In sediments undergoing first-time burial and currently exposed to their historically maximum applied stresses, C can be relatively large. Here, fluid pressure increases are principally due to mechanical causes, and overpressuring will be associated with undercompaction. The tendency for undercompaction (compaction disequilibrium) depends on the sediment thickness, burial rate and vertical permeability. In other cases, when applied stresses have been reduced by uplift, or when impermeable hard caps or seals have been formed, C may be substantially smaller. Here pore pressures may be predominantly controlled by diagenetic and aquathermal processes, with mechanical (undercompaction) phenomena being relatively less significant.Three-dimensionally sealed overpressured zones may exhibit vertical fluid pressure discontinuities. Within a sealed aquifer, fluid pressures may rise to almost lithostatic values, relieved by episodic fracturing of the seal.

scholarly journals Identification of carotenoid pigments of pumpkin grown in the South of Russia

2020 ◽  
Vol 161 ◽  
pp. 01106
Author(s):  
Lyudmila Rodionova ◽  
Irina Sobol ◽  
Lyudmila Donchenko ◽  
Natalia Limareva
Keyword(s):  
Chemical Analysis ◽  
Nutritional Value ◽  
Raw Material ◽  
Carotenoid Pigments ◽  
Modern Methods ◽  
Time Differential ◽  
Quantitative Characteristics ◽  
Long Time ◽  
Physical And Chemical

The article presents the results of studies of changes in the vitamin composition of pumpkin, grown in the Kuban region. Standard and modern methods of physical and chemical analysis were used in the research. It is shown that the nutritional value of this raw material allows to maintain its nutritional value for a long time. Differential determination of carotenoid pigments contained in pumpkin fruits was carried out. The quantitative characteristics of carotenoids were established and the predominant carotenoid pigments for the studied pumpkin varieties were specified.

Numerical Prediction and Optimization of Depressurized Sodium-Water Reaction Experiment With Counter-Flow Diffusion Flame

2008 ◽  
Author(s):  
Akira Yamaguchi ◽  
Takashi Takata ◽  
Hiroyuki Ohshima ◽  
Yoshitaka Kohara
Keyword(s):  
Diffusion Flame ◽  
Liquid Sodium ◽  
Counter Flow ◽  
Pressurized Water ◽  
Sodium Fast Reactor ◽  
Transfer Tube ◽  
Reaction Region ◽  
Long Time ◽  
Design Basis Accident ◽  
Physical And Chemical

Sodium-water reaction (SWR) is a design basis accident of a Sodium Fast Reactor (SFR). A breach of the heat transfer tube in a steam generator (SG) results in contact of liquid sodium with water. Typical phenomenon is that the pressurized water blows off, vaporizes and mixes with the liquid sodium. In this paper, a new computer program has been developed and the SWR in a counter-flow diffusion flame is studied by a numerical simulations and an experiment. The experiment is designed with the numerical simulation so that the stable reaction flame is maintained for long time and physical and chemical quantities are measured. From the comparison of analysis and experiment, there exist discrepancies that may be caused by the assumptions of chemical reaction. Hence, a new experiment is proposed to enhance the measurement accuracy and to investigate the reason of the disagreement. The authors propose a depressurized experiment. With the depressurization, it is expected the flame location can be controlled and the reaction region becomes thicker because of decrease in reactant gas density.

The Research on the Stress Analysis of Overhead Steam Pipeline

2020 ◽  
Author(s):  
Zhe Pu ◽  
Jielu Wang ◽  
Bin Ren ◽  
Pan Song ◽  
Fan Zhao
Keyword(s):  
High Temperature ◽  
Stress Analysis ◽  
Industrial Production ◽  
Inspection Method ◽  
Steam Pipeline ◽  
Periodic Inspection ◽  
Whole Plant ◽  
Calculation Results ◽  
Long Time ◽  
Physical And Chemical

Abstract Industrial production is accompanied by a large number of physical and chemical reactions. Steam, whose heat was often used to carry out various production activities, is a common medium in industrial production. Steam pipeline has the characteristics of high temperature and high pressure. The pipeline has been in service at high temperature for a long time, which is prone to metal material degradation such as graphitization and spheroidization. Cause of the expansion of steam pipeline after heating, the natural compensation structure is generally adopted in the whole plant pipe gallery. In recent years, the accidents of steam pipeline occurred frequently, so we must pay more attention to the safety of steam pipeline. Periodic Inspection Regulation for Industrial Pressure Piping (TSG D7005-2018) explicitly requires stress analysis and checking in some cases to determine the safety of the pipeline. The traditional inspection method adopts a random sampling model which has the risk of over inspection and missing inspection. Taking a whole plant steam pipeline as an example, this paper introduced the stress check criterion of pipeline in ASMEB31.3.The model of the pipeline was established by the software, and the stress state and displacement of each node of the pipeline were calculated. According to the calculation results, a targeted inspection scheme was established and effective data support was provided for the regular inspection of steam pipeline.

Review of Physical and Chemical Properties of Perfluorooctanyl sulphonate (PFOS) with Respect to its Potential Contamination on the Environment

2012 ◽  
Vol 518-523 ◽  
pp. 2183-2191 ◽  
Author(s):  
Sheng Zhang ◽  
David N Lerner
Keyword(s):  
Chemical Properties ◽  
Hydrocarbon Fuel ◽  
The United States ◽  
Breakthrough Curves ◽  
Film Forming ◽  
Perfluorinated Surfactants ◽  
Blood Banks ◽  
Single Well ◽  
Physical And Chemical ◽  
By Products

Perfluorinated surfactants have emerged as priority environmental contaminants due to their detection in environmental and biological matrices as well as concerns regarding their persistence and toxicity. They have been found in groundwater, particularly at sites used for training firefighters. They do not biodegrade easily in groundwater, and are not retarded during transport. The most common chemical is Perfluorooctanyl Sulphonate (PFOS), which is mainly used in aqueous film forming foam (AFFF) to extinguish hydrocarbon-fuel fires. It is also used in many herbicide and insecticide formulations, cosmetics, greases and lubricants, paints, polishes, and adhesives. PFOS and related fluoro-organic chemicals have been used since the 1950s. A quantity of fluorosurfactants and related products are still in use all over the world. Intensive studies over the last few years discovered that PFOS and certain by-products were both ubiquitous in the environment and highly persistent. PFOS does not biodegrade in the environment and very limited degradation has been observed in wastewater treatment. The breakthrough curves of a single-well push-pull test indicated that there was no retardation for PFOS as well. It was detected in part-per-billion levels in blood samples obtained from blood banks in the United States, Japan, Europe, and China. There have been more and more reports on the accumulation and effect of PFOS in wild animals’ liver, serum and muscle as well. This suggests that PFOS can bioaccumulate to higher levels of the food chain.

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