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Bioactive Ceramics and Metals for Regenerative Engineering
Published in Yusuf Khan, Cato T. Laurencin, Regenerative Engineering, 2018
Changchun Zhou, Xiangfeng Li, Junqiu Cheng, Hongsong Fan, Xingdong Zhang
When metals react with body fluid, they release electrons and form positive ions. In electrochemistry, the values of standard electrode potential provide a way to compare the relative ease of different metal elements to lose electrons and form ions in solutions. For biodegradable metals, they have a greater tendency to form their ions compared to hydrogen. The degradation mechanism of BMs is mainly electrochemical corrosion, and electrochemical measurements are conduced to predict the corrosion rate of BMs in vitro.
Electrodeposition
Published in Vidya Nand Singh, Chemical Methods for Processing Nanomaterials, 2021
The term electrochemistry deals with the chemical and electrical phenomena in chemical reactions that exchange energies among the participating species. The chemical reactions involving ionic species can readily give rise to an electromotive force (emf) or potential, as in batteries or fuel cells. Conversely, the application of emf in a solution of ions or molten salts brings about the chemical reactions that may form or deposit a new material. This process is known as electrodeposition. In a typical electrodeposition process, an electrode (a solid, electronically conductive support or substrate) is immersed into an electrolyte (ionic conductor) containing positive or negative ions of the material to be deposited. Application of a certain emf or potential across the electrode/electrolyte interface brings about a charge transfer reaction known as a half-cell electrochemical reaction that results in the precipitation/ deposition of material onto the substrate. Similarly, another half-cell electrochemical reaction occurs at the other electrode, forming an electrochemical cell in which an electrical charge involving the transfer of electrons and ions, is passed. The driving force for such an electrochemical process is the applied potential, which dictates the material formation process, its nano-to-micro-structural evolution, and other physicochemical properties. The efficiency of such electrochemical reactions depends on several factors, such as the thermodynamics and kinetics of electrolyte, charge and electron transfer processes, and the interfacial electrode processes. This chapter is precisely focussed on the electrochemical synthesis overview of metals and semiconductor nanostructures.
Electrochemical Studies for Biomedical Applications
Published in Mu Naushad, Saravanan Rajendran, Abdullah M. Al-Enizi, New Technologies for Electrochemical Applications, 2020
Analytical chemistry is the field where analytical techniques determine an analyte’s concentration or characterize the chemical reactivity by measuring its potential, charge, or current (Siddiqui, AlOthman, and Rahman 2013). Electrochemistry is a branch of analytical chemistry that deals with the interaction of electrical and chemical effects; where the chemical changes are due to the passage of electrical current and the production of electrical energy by chemical reaction. Movement of electrons is an oxidation–reduction reaction, hence this field is named electrochemistry (Prabhulkar et al. 2012). Though there is much diversity in instrumentation, the majority of the electrochemical techniques and methods share numerous similar features (Kim et al. 2011). Because of its high sensitivity and precision, as well as a broad linear dynamic range with relatively economical instrumentation, these electrochemical methods (Figure 15.1) have become dominant and versatile analytical techniques in the field of biomedical applications (Nemiroski et al. 2014; Turner 2013). In traditional laboratories, this can be time-consuming and expensive. It is attractive to provide low-cost fabrication methods and point-of-care diagnostic tools with the capacity to detect and check various biological and chemical compounds. By combining well-established materials and fabrication methods, it is possible to produce electrochemical devices that meet the needs of many patients, healthcare and medical professionals, and environmental specialists. Furthermore, continuing to innovate, by merging each of these favorable electrochemical sensing techniques and materials, is incredibly selective and provides accurate and repeatable quantitative results without expensive measurement equipment.
State of play in technology and legal framework of alternative marine fuels and renewable energy systems: a bibliometric analysis
Published in Maritime Policy & Management, 2022
Paweł Kołakowski, Mateusz Gil, Krzysztof Wróbel, Yuh-Shan Ho
The most productive of those with TP above 10, are presented in Table 5 (for a full version of the collation please see Table A3 in the Appendix). Furthermore, the annual publications of the top five productive subject categories are analyzed in Figure 6. The number of scientific articles per category grew steadily since 2006, which indicates that the study subject had been systematically developed across various categories. In terms of an increasing number of articles, the energy and fuels category is the leading one during the study period. Physical chemistry, electrochemistry, and marine engineering attracted far less interest and thus were increasing at a slower rate. Noticeable is that the environmental sciences WoS category signifies an increase since 2018. That could be influenced by a strong focus on international environment-friendly strategies in the relation to GHG emission reduction. With increasing funding devoted to environmental research (Overland and Sovacool 2020) comes additional scientific output.
Ion-pairs of structurally related polyoxotantalate clusters and divalent metal cations
Published in Journal of Coordination Chemistry, 2020
Jiahui Chen, Yachun Ma, Dongdi Zhang, Yuqing Yang, Mrinal K. Bera, Jiancheng Luo, Ehsan Raee, Tianbo Liu
Polyoxometalates (POMs) are nanosized clusters built from metal oxide octahedra and heteroatoms. POMs have drawn substantial interest due to their applications in electrochemistry, catalysis, magnetism, supramolecular chemistry, etc. Among the pioneers in the POM chemistry, Professor En-Bo Wang and his colleagues made important contributions [1–6]. One reason that POMs feature such plentiful properties is due to their structural versatilities. Examples of well-defined structures include Keggin, Dawson, Anderson, Waugh, Strandberg, Lindqvist, Keplerate, Preyssler, etc., and some structures exhibit isomerism typically based on rotation of building units [7–9]. Isomers of POMs can be synthesized by carefully tuning the reaction conditions; structure transitions can be achieved in some cases. Slight changes in the isomeric structure can induce significant changes in the properties of POMs. For example, the isomers of Keggin POMs demonstrate different stabilities and redox properties [10]. This leads to an important topic of how to correlate the isomeric structures of a cluster with their properties.
Parallel Inductor Multilevel Current Source Inverter for Input Ripple Current Reduction in PEM Fuel Cell Applications
Published in IETE Journal of Research, 2020
Nik Fasdi Nik Ismail, Nasrudin Abd. Rahim, Siti Rohani Sheikh Raihan, Yusuf Al-Turki
However, storing this energy is problematic and challenging: batteries or storage units perform well over short timescales, but over periods of months or year different methods are necessary, making storage units not attractive options for utility companies and consumers [1]. Energy storage in the form of hydrogen offers a possible alternative. This energy storage or a fuel cell is a direct electrochemical energy conversion device. Through electrochemistry, fuel cell directly converts chemical energy into electrical energy. Unlike a battery which can be depleted, a fuel cell will continue to produce electricity as long as hydrogen is supplied. The potential for highly reliable and long-lasting systems can be achieved [2]. Nevertheless, fuel cell technology is still new and faces challenges and barriers to its implementation such as the cost of the fuel cell, power density and performance, hydrogen storage and fuel cell durability under start-stop cycling [2,3].