BARACK OBAMA'S ADDRESS TO THE 2004 DEMOCRATIC NATIONAL CONVENTION

DAVID A. FRANK,MARK LAWRENCE MCPHAIL 한국수사학회 2009 수사학 Vol.0 No.10

MCFC fed with biogas: Experimental investigation of sulphur poisoning using impedance spectroscopy

Cigolotti, V.,McPhail, S.,Moreno, A.,Yoon, S.P.,Han, J.H.,Nam, S.W.,Lim, T.H. Pergamon Press ; Elsevier Science Ltd 2011 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.36 No.16

The combination of biogas from anaerobic digestion and molten carbonate fuel cell (MCFC) enables highly efficient utilisation of a renewable energy source, maximizing the energetic yield from alternative fuels and minimizing environmental impact in terms of polluting emissions. However, the contaminant levels in the biogas are often unacceptable for performing and durable operation of an MCFC; it is thus desirable to establish and improve the tolerance level of the fuel cell to these contaminants. In this work, the effect of hydrogen sulphide (H<SUB>2</SUB>S) in the fuel gas is investigated on the electrochemical performance and the regenerative capacities of a single MCFC. Different concentrations of H<SUB>2</SUB>S (1, 3, 5, 8 ppm) were added to the anode gas composition during cell operation and the respective effects are investigated. Electrochemical impedance measurements are carried out to identify the processes which take place in the anode. Experimental results will be presented, showing the effects and implications of cell poisoning with H<SUB>2</SUB>S, the most common contaminant from biogas produced by anaerobic digestion, harmful to both the MCFC anode and the reforming catalyst. This investigation is required in order to identify the tolerance limits of current MCFC materials, especially as regards different concentrations of H<SUB>2</SUB>S that can occur due to composition variations of the produced biogas.

Wewakamide A and Guineamide G, Cyclic Depsipeptides from the Marine Cyanobacteria Lyngbya semiplena and Lyngbya majuscula

( Han Bing Nan ),( Harald Gross ),( Kerry L. Mcphail ),( Doug Goeger ),( Claudia S. Maier ),( William H. Gerwick ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.9

Two new cyclic depsipeptides wewakamide A (1) and guineamide G (2) have been isolated from the marine cyanobacterium Lyngbya semiplena and Lyngbya majuscula, respectively, collected from Papua New Guinea. The amino and hydroxy acid partial structures of wewakamide A and guineamide G were elucidated through extensive spectroscopic techniques, including HR-FABMS, 1D 1H and 13C NMR, as well as 2D COSY, HSQC, HSQCTOCSY, and HMBC spectra. The sequence of the residues of wewakamide A was determined through a combination of ESI-MS/MS, HMBC, and ROESY. Wewakamide A possesses a β-amino acid, 3-amino-2-methylbutanoic acid (Maba) residue, which has only been previously identified in two natural products, guineamide B (3) and dolastatin D (4). Although both new compounds (1,2) showed potent brine shrimp toxicity, only guineamide G displayed significant cytotoxicity to a mouse neuroblastoma cell line with LC50 values of 2.7 ?M.

Experimental analysis of SO₂ effects on Molten Carbonate Fuel Cells

Di Giulio, N.,Bosio, B.,Han, J.,McPhail, S.J. Pergamon Press ; Elsevier Science Ltd 2014 International journal of hydrogen energy Vol.39 No.23

The aim of this work is to investigate how SO<SUB>2</SUB> can affect MCFC performance and to discover the possible mechanisms involved in cathode sulphur poisoning, specifically considering the possible use of MCFCs in CCS (Carbon Capture and Storage) application. The different contributions of cathodic, anodic and electrolyte reactions have been considered to get a complete picture of the evolution of performance degradation. Experimental tests have been performed at the Fuel Cell Centre laboratories of Korea Institute of Science and Technology (KIST) thanks to 100 cm<SUP>2</SUP> single cell facilities and comparing results using both an optimized gas for laboratory conditions and a gas composition that simulates MCFCs when running in a Natural Gas Combined Cycle (NGCC) power plant. Polarisation curves, endurance tests, impedance measurements and gas analyses have been carried out to support the investigation.

Accurate in-operando study of molten carbonate fuel cell degradation processes -part I: Physiochemical processes individuation

Santoni, F.,Della Pietra, M.,Pumiglia, D.,Boigues Muñ,oz, C.,McPhail, S.J.,Cigolotti, V.,Nam, S.W.,Kang, M.G.,Yoon, S.P. Elsevier 2018 ELECTROCHIMICA ACTA Vol.291 No.-

<P><B>Abstract</B></P> <P>This work has the difficult task to deeply study the electrochemical processes that occur inside a 100 cm<SUP>2</SUP> of Molten Carbonate Fuel Cells (MCFC) impedance spectra using the high resolution of Distribution of Relaxation Time (DRT) method. Using this method, it is possible to shed light on the different physicochemical processes occurring within these cells, identifying the characteristic relaxation times by means of an appropriate experimental campaign where temperature and gas compositions in anode and cathode were varied one at a time. The quality of the recorded spectra was verified by Kramers-Kronig relation before applying DRT calculations. In this work, five distinct and separated peaks with different time constants ranging from 0.01 to 500 Hz were identified and associated with physiochemical processes of the cell. Three peaks at high frequency represent the charge transfer processes in anode and cathode active sites. The other two, located at low frequency, are associated with the gas diffusion in the electrodes and to the gas conversion process. This study represents the first application of the DRT approach to this technology allowing to understand the physicochemical origin of the individual polarization processes controlling the cell performance and the degradation. The analysis of degradation processes using the DRT method and the physiochemical processes identification presented in this paper will be shown in part II of this work.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The first application of DRT approach to MCFC impedance Spectra is presented. </LI> <LI> Five processes controlling the cell performance are individuated using DRT method. </LI> <LI> Repeatability and reproducibility of the DRT results in MCFCs are demonstrated. </LI> <LI> Three peaks with a high-frequency domain are related to Charge Transfer Processes. </LI> <LI> Two peaks with a low-frequency domain are associated with Mass Transfer Mechanisms. </LI> </UL> </P>

Experimental influence of operating variables on the performances of MCFCs under SO₂ poisoning

Di Giulio, N.,Audasso, E.,Bosio, B.,Han, J.,McPhail, S.J. Elsevier 2015 International journal of hydrogen energy Vol.40 No.19

<P><B>Abstract</B></P> <P>Molten Carbonate Fuel Cells have reached the status of commercialization and are now ready for the challenge of market penetration. Nevertheless, new innovative applications such as the use of non-conventional fuels and their possible implementation in a Carbon Capture and Storage system, have given new importance to research activities. In particular, the gas feedings used in these applications contain impurities that can damage MCFCs and, of these, sulphur compounds seem to be the most harmful, even at low concentrations.</P> <P>The aim of this work is to test the effect of SO<SUB>2</SUB> on the role of the operating variables governing the electrochemical kinetics of MCFCs, investigate the relationships and advance additional data necessary for the reading of the complex interaction phenomena taking place in these conditions. The current work is therefore not intended to probe into the fundamental electrochemical mechanisms, but more to validate the window of viable operating conditions that can be expected in real applications. In particular, an experimental campaign was performed, feeding 2 ppm of SO<SUB>2</SUB> to the cathode of MCFC single-cells at different operating temperature and gas partial pressures (H<SUB>2</SUB>, CO<SUB>2</SUB>, O<SUB>2</SUB>), taking into account possible chemical, electrochemical and physical poisoning mechanisms.</P> <P>The experimental tests were performed at the Fuel Cell Research Centre laboratories of KIST (South Korea) and a preliminary theoretical analysis was also proposed to suggest operating strategies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Low temperatures favour the SO<SUB>2</SUB> poisoning effect, especially under 640 °C. </LI> <LI> Optimal range for hydrogen composition is between 40% and 60%. </LI> <LI> The Oxygen concentration does not influence SO<SUB>2</SUB> poisoning for CO<SUB>2</SUB>/O<SUB>2</SUB> < 0.9. </LI> <LI> CO<SUB>2</SUB> compositions under 6% strongly amplify the impact of SO<SUB>2</SUB> poisoning. </LI> </UL> </P>

The electrochemical studies of the corrosion resistance behaviour of hydroxyapatite coatings on stainless steel fabricated by electrophoretic deposition

Kean-Khoon Chew,Sharif Hussein Sharif Zein,Abdul Latif Ahmada,David S. McPhail,Muhammad Faiq Abdullah 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.4

HA was coated on stainless steel (SS) 316L by using electrophoretic deposition to impart corrosion resistance upon SS 316L. Consequently, corrosion behaviour of HA coated SS 316L deposited from applied voltages 10 V to 60 V (denoted as HA/SS316L-10V until -60V) was evaluated in comparison with pristine SS 316L by various electrochemical studies. As results, linear potentiodynamic polarisation result suggested that HA/SS316L-40V exhibits highest open circuit potential indicating that successful protection of HA coating. Additionally, cyclic polarisation studies revealed that HA coated SS 316L improves pitting corrosion resistance. Finally, EIS results demonstrated that higher polarisation resistance and lower capacitance values for HA/SS316L-40V.