scholarly journals A Study of Recycling Process of Cobalt-based Conversion Coating Formed on Aluminium Alloys

2021 ◽  
Author(s):  
Di MA ◽  
Shubai LI ◽  
Dongmei YU ◽  
Bin WANG ◽  
Zou CHEN ◽  
...  

In this study, the influence of different cyclic treatment and reuse process on the performance of the conversion film was systematically studied by electrochemical test, surface characterization and determination of cobalt ions in the conversion solution, and new technology of chemical conversion of cobalt salts in aluminum alloys were determined. Mode A indicated the practice of cyclical processing of the test object in the original conversion solution, in which components of the circulation liquid were consumed continuously. After the first cycle, the Ecorr and Rp were – 691.8 V and 63.5 kΩ. In the later time, Rp was just about 13.0 kΩ, and the corrosion resistance of conversion film degraded progressively. Mode B represented the practice of adding to the original solution before cyclical processing of the test object, so that volume of the solution remains unchanged, and components of the circulation liquid kept increasing. RP increased from 9.3 kΩ to the 69.9 kΩ at the beginning of the cycle, followed by a slow descent, and content of cobalt in the film was stable, also higher than that under model A. This demonstrates that mode A has high utilization of the cobalt in the conversion solution in the early recycling, whereas mode B can prolong the cyclic service life of the conversion solution in circulation. After adding oxidants, as NaClO3, NaBrO3, H2O2, NaClO, and KMnO4, to the circulation liquid before recycling, the reuse and recycle ratio of cobalt reaches up to 41.3 %, and Rp can be promoted to123.2 kΩ at most. The life of the recycling was prolonged, while the costs of chemical conversion of cobalt were reduced.

2021 ◽  
Author(s):  
Jędrzej Matla ◽  
Kaźmierczak Andrzej

The following article presents the method of verification of EURO III standard in real life conditions for special vehicles. The test object qualified as a special vehicle of N3G category was tested in road conditions along a defined route, and then the obtained measurement results were compared to the exhaust emission standard (EURO III) applicable for this vehicle in transient testing mode. A method of comparing the emission factors in road conditions with the indicators obtained on the engine dynamometer was proposed. An AVL mobile exhaust gas analyzers (PEMS) dedicated for the Real Driving Emissions (RDE) road tests were used in the research.


2020 ◽  
Vol 6 (6) ◽  
pp. 48-54
Author(s):  
M. Dziuba ◽  
L. Mushinskii ◽  
R. Brovko ◽  
V. Doluda

The surface properties of microporous aluminosilicates are of primary importance in chemical technology and catalysis. The determination of the surface area, pore volume, and pore size and size distribution for microporous aluminosilicates is a complex scientific and technical problem related to both accurate measurements and the correct choice of a mathematical model that adequately describes the physicochemical processes occurring on the test surface. Currently, t-plot, as-plot, Dubinin-Radushkevich model, Dillimore model and Horvath-Kawazoe model are frequently used, each of which has certain advantages and certain disadvantages, to determine micropores in the material. It should be noted that t-plot model found the most frequent use. This is a consequence of the good correlation of volumes and pore areas obtained with its help with theoretically calculated values for various materials. In this point, the article provides a calculation of Zn-modified zeolite H-ZSM-5 surface properties using the t-plot model, for which nitrogen adsorption isotherms were originally obtained. The nitrogen adsorption isotherms of the initial zeolite H-ZSM-5 can be attributed to the first type of isotherms, and the modified samples to the fourth type of isotherms according to Brunauer’s classification. It was found that the initial zeolite is a typical microporous zeolite of H-ZSM-5 type, while the modified samples are micro- and mesoporous materials. Calculation of nitrogen adsorption isotherms using the t-plot model allows to determine the volume of micro and mesopores, which varied in the range of 0.11–0.14 cm3/g for micropores and 0.04–0.07 cm3/g for mesopores. Based on the obtained data, it can be concluded that when zeolite is modified with zinc at a zinc concentration less than 15 wt.%, micropores are not filled with zinc, while mesopores are predominantly filled and an additional surface of zinc oxide is formed on the external surface of the zeolite.


2016 ◽  
Vol 27 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Klester Santos Souza ◽  
Ruth Flavia Vera Villamil Jaimes ◽  
Sizue Otta Rogero ◽  
Pedro Augusto de Paula Nascente ◽  
Silvia Maria Leite Agostinho

Abstract In order to evaluate its application as a dental prosthesis material, a CoCrW alloy was subjected to in vitro cytotoxicity test, surface characterization and electrochemical studies performed in artificial saliva and 0.15 mol.L-1 NaCl medium. The used techniques were: anodic polarization curves, chronoamperometric measurements, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) analysis and X-ray photoelectron spectroscopy (XPS). Cytotoxicity test was also performed. The electrochemical behavior of CoCrW alloy was compared in both studied media, from corrosion potential (Ecorr) to a 600 mV anodic overvoltage. From the electrochemical measurements it was observed that the CoCrW alloy in both media presents only generalized corrosion. SEM and EDS analysis showed that the alloy presents carbide niobium and silicon and manganese oxides as nonmetallic inclusions. XPS results indicated that cobalt does not significantly contribute to the passivating film formation. Cytotoxicity test showed no cytotoxic character of CoCrW alloy. These results suggest that the CoCrW alloy can be used as biomaterial to be applied as prosthesis in dental implants.


Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 493
Author(s):  
Daniel Schwabl ◽  
Markus Bauer ◽  
Markus Lehner

In this paper, an arc was drawn over ten years of research activities from three chairs of the Montanuniversitaet Leoben, as well as industrial partners. The superior objective of this research effort was to develop a wet-mechanical process for the recovery of polyolefin concentrates (90 wt% polyolefins) from mixed waste fraction for use in chemical recycling and to advance this new technology to commercial maturity. As a bridge technology, it would close the gap between state-of-the-art dry processing of mixed plastic waste materials and chemical plastic recycling via thermo-chemical conversion. The methods used were mainly tested in a lab-scale plant with a throughput capacity of 50 to 200 kg/h depending on the bulk density of the used feedstock. Further studies for the treatment and usage of the main products and by-products, as well as chemical analyses of them, were completed during the investigation. Within these series of tests, polyolefin concentrates, which satisfied the requirements for chemical recycling, could be recovered. With these data, a concept for an industrial pilot plant was developed and evaluated from an economic point of view. According to this evaluation, the realization of such an industrial pilot plant can be recommended.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
E.D. Wolf

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.


Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.


2020 ◽  
Vol 477 (14) ◽  
pp. 2679-2696
Author(s):  
Riddhi Trivedi ◽  
Kalyani Barve

The intestinal microbial flora has risen to be one of the important etiological factors in the development of diseases like colorectal cancer, obesity, diabetes, inflammatory bowel disease, anxiety and Parkinson's. The emergence of the association between bacterial flora and lungs led to the discovery of the gut–lung axis. Dysbiosis of several species of colonic bacteria such as Firmicutes and Bacteroidetes and transfer of these bacteria from gut to lungs via lymphatic and systemic circulation are associated with several respiratory diseases such as lung cancer, asthma, tuberculosis, cystic fibrosis, etc. Current therapies for dysbiosis include use of probiotics, prebiotics and synbiotics to restore the balance between various species of beneficial bacteria. Various approaches like nanotechnology and microencapsulation have been explored to increase the permeability and viability of probiotics in the body. The need of the day is comprehensive study of mechanisms behind dysbiosis, translocation of microbiota from gut to lung through various channels and new technology for evaluating treatment to correct this dysbiosis which in turn can be used to manage various respiratory diseases. Microfluidics and organ on chip model are emerging technologies that can satisfy these needs. This review gives an overview of colonic commensals in lung pathology and novel systems that help in alleviating symptoms of lung diseases. We have also hypothesized new models to help in understanding bacterial pathways involved in the gut–lung axis as well as act as a futuristic approach in finding treatment of respiratory diseases caused by dysbiosis.


2019 ◽  
Vol 28 (4) ◽  
pp. 993-1005 ◽  
Author(s):  
Gitte Keidser ◽  
Nicole Matthews ◽  
Elizabeth Convery

Purpose The aim of this study was to examine how hearing aid candidates perceive user-driven and app-controlled hearing aids and the effect these concepts have on traditional hearing health care delivery. Method Eleven adults (3 women, 8 men), recruited among 60 participants who had completed a research study evaluating an app-controlled, self-fitting hearing aid for 12 weeks, participated in a semistructured interview. Participants were over 55 years of age and had varied experience with hearing aids and smartphones. A template analysis was applied to data. Results Five themes emerged from the interviews: (a) prerequisites to the successful implementation of user-driven and app-controlled technologies, (b) benefits and advantages of user-driven and app-controlled technologies, (c) barriers to the acceptance and use of user-driven and app-controlled technologies, (d) beliefs that age is a significant factor in how well people will adopt new technology, and (e) consequences that flow from the adoption of user-driven and app-controlled technologies. Specifically, suggested benefits of the technology included fostering empowerment and providing cheaper and more discrete options, while challenges included lack of technological self-efficacy among older adults. Training and support were emphasized as necessary for successful adaptation and were suggested to be a focus of audiologic services in the future. Conclusion User perceptions of user-driven and app-controlled hearing technologies challenge the audiologic profession to provide adequate support and training for use of the technology and manufacturers to make the technology more accessible to older people.


2014 ◽  
Vol 4 (1) ◽  
pp. 23-29
Author(s):  
Constance Hilory Tomberlin

There are a multitude of reasons that a teletinnitus program can be beneficial, not only to the patients, but also within the hospital and audiology department. The ability to use technology for the purpose of tinnitus management allows for improved appointment access for all patients, especially those who live at a distance, has been shown to be more cost effective when the patients travel is otherwise monetarily compensated, and allows for multiple patient's to be seen in the same time slots, allowing for greater access to the clinic for the patients wishing to be seen in-house. There is also the patient's excitement in being part of a new technology-based program. The Gulf Coast Veterans Health Care System (GCVHCS) saw the potential benefits of incorporating a teletinnitus program and began implementation in 2013. There were a few hurdles to work through during the beginning organizational process and the initial execution of the program. Since the establishment of the Teletinnitus program, the GCVHCS has seen an enhancement in patient care, reduction in travel compensation, improvement in clinic utilization, clinic availability, the genuine excitement of the use of a new healthcare media amongst staff and patients, and overall patient satisfaction.


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