9,162 research outputs found
A robotic platform for high-throughput electrochemical analysis of chalcopyrite leaching
A novel robotic platform for combinatorial screening of ionic liquid-based Cu extraction from chalcopyrite with real-time, in situ monitoring of dissolved copper.</p
Simultaneous Ejection of Six Electrons at a Constant Potential by Hexakis(4-ferrocenylphenyl)benzene
A simple synthesis of a dendritic hexaferrocenyl electron donor (5) is described in which six ferrocene moieties are connected at the vertices of the propeller of the hexaphenylbenzene core. The molecular structure of 5 is confirmed by X-ray crystallography. An electrochemical analysis along with redox titrations (which are tantamount to coulometry) confirmed that it ejects six electrons at a single potential
Molecular Actuator: Redox-Controlled Clam-Like Motion in a Bichromophoric Electron Donor
The one-electron oxidation of tetramethoxydibenzobicyclo[4.4.1]undecane (4) prompts it to undergo a clam-like electromechanical actuation into a cofacially Ļ-stacked conformer as established by (i) electrochemical analysis, (ii) by the observation of the intense charge-resonance transition in the near IR region in its cation radical spectrum, and (iii) by X-ray crystallographic characterization of the isolated cation radical salt (4+ā¢ SbCl6ā)
X-ray Structural Characterization of Charge Delocalization onto the Three Equivalent Benzenoid Rings in Hexamethoxytriptycene Cation Radical
Definitive X-ray crystallographic evidence is obtained for a single hole (or a polaron) to be uniformly distributed on the three equivalent 1,2-dimethoxybenzenoid (or veratrole) rings in the hexamethoxytriptycene cation radical. This conclusion is further supported by electrochemical analysis and by the observation of an intense near-IR transition in its electronic spectrum, as well as by comparison of the spectral and electrochemical characteristics with the model compounds containing one and two dimethoxybenzene rings
Electrochemical Analysis of Coffee
The objective of this study was to determine if there is a correlation between the chemical analysis of coffee and its variety of flavors. Different types of coffee have varying chemicals, with one of the components being the differing types and quantities of polyphenols. In order to study the correlation of coffee structure and flavor, electrochemical analysis of varying coffee samples was performed. The types of analyses utilized include Cyclic Voltammetry and UV Spectroscopy, along with pH. Cyclic Voltammetry was an excellent method since it is quick, easily performed, and cost effective. UV Spectroscopy was also used to compare the structures of the varying coffee types with the determined flavor profiles of each sample. The differing acidity and alkalinity between the coffee types may play a role in the taste of each sample, which was also analyzed in this study. Flavor profiles were determined by a panel of taste testers who were given specific parameters that were used to characterize the tastes of the coffees sampled. Although taste is usually subjective among individuals, the results of the electrochemical analyses were compared to the flavor profiles assigned to each sample
Sensitive electrochemical assays of DNA structure
Electrochemical methods have been used to study the structure and function of nucleic acids for more than 50 years. These approaches complement other experimental techniques, which we illustrate by using examples from studies of processes involved in the repair of DNA damage. The excellent sensitivity of the electrochemical approaches makes them good candidates for use as biosensors of a wide range of molecules and biological processes
Phosphoric acid fuel cell power plant system performance model and computer program
A FORTRAN computer program was developed for analyzing the performance of phosphoric acid fuel cell power plant systems. Energy mass and electrochemical analysis in the reformer, the shaft converters, the heat exchangers, and the fuel cell stack were combined to develop a mathematical model for the power plant for both atmospheric and pressurized conditions, and for several commercial fuels
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Experimental and Theoretical Evidence for Nitrogen-Fluorine Halogen Bonding in Silver-Initiated Radical Fluorinations
We
report experimental and computational evidence for nitrogenāfluorine
halogen bonding in AgĀ(I)-initiated radical CāH fluorinations.
Simple pyridines form [NāFāN]+ halogen bonds
with Selectfluor to facilitate single-electron reduction by catalytic
AgĀ(I). Pyridine electronics affect the extent of halogen bonding,
leading to significant differences in selectivity between mono- and
difluorinated products. Electronic structure calculations show that
halogen bonding to various pyridines alters the single-electron reduction
potential of Selectfluor, which is consistent with experimental electrochemical
analysis. Multinuclear correlation NMR also provides spectroscopic
evidence for pyridine halogen bonding to Selectfluor under ambient
conditions
Particulate counter electrode system for enhanced light harvesting in dye-sensitized solar cells
A particulate counter electrode with photo scattering and redox catalytic properties is applied to dye sensitized solar cells (DSSCs) in order to improve photo conversion efficiency and simplify the assembly process. Our particulate counter electrode acts as both a photo reflecting layer and a catalyst for reduction of electrolyte. The reflective and catalytic properties of the electrode are investigated through optical and electrochemical analysis, respectively. A short circuit current density enhancement is observed in the DSSCs without the need to add an additional reflecting layer to the electrode. This leads to a simplified assembly process. (C) 2013 Optical Society of Americ
āA devotion to the experimental sciences and artsā: the subscription to the great battery at the Royal Institution 1808ā9
A significant but neglected theme in the history of British science in the nineteenth century is the funding of institutional research. The subscription to the āgreat batteryā at the Royal Institution in 1808 and 1809 provides the first instance of named individuals prepared to commit themselves to the provision of apparatus to be used for research in the new field of electrochemistry. This paper analyses the subscribers who were deemed to be āenlightenedā and whom Humphry Davy subsequently described as āa few zealous cultivators and patrons of scienceā. Using information from the subscription list, a distinction is made between the individual subscriptions pledged and the sums actually paid. In contextualizing the subscription, insights are provided into the Royal Society, the contemporary scientific community and the politics of metropolitan science. The voltaic subscription represents an early example of the repercussions of the nature of research funding for institutional finances and governance
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