The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Burtron H. Davis - One of the best experts on this subject based on the ideXlab platform.

  • ^14C-Labeled Alcohol Tracer Study: Comparison of Reactivity of Alcohols over Cobalt and Ruthenium Fischer–Tropsch Catalysts
    Topics in Catalysis, 2015
    Co-Authors: Muthu Kumaran Gnanamani, Venkat Ramana Rao Pendyala, Dennis E. Sparks, Debanjan Chakrabarti, Arno Klerk, Robert A. Keogh, Wilson D. Shafer, Burtron H. Davis
    Abstract:

    The reactivity of ^14C-labeled ethanol (CH _3 ^14 CH_2OH) and 1-propanol (CH_3CH _2 ^14 CH_2OH) added during Fischer–Tropsch synthesis (FTS) was studied in a continuous-flow well-stirred reactor operated at 220 °C and 18.7 atm using a supported cobalt or ruthenium catalyst. The added labeled alcohols are mostly found in the product gas and water phase (≥99 %) without being involved in any reaction over both fcc and hcp metallic cobalt. The data indicate that C–O bond of ethanol and 1-propanol remains mostly stable on cobalt under FTS conditions. However, 1-propanol is likely to be involved in a chain initiation after decarbonylation apart from being degraded into methanol on ruthenium.

  • 13C-Tracer Study of the Fischer–Tropsch synthesis: another interpretation
    Catalysis Today, 2000
    Co-Authors: Burtron H. Davis
    Abstract:

    Abstract The 13C-Tracer results from the introduction of 13C2H4 into syngas prior to conversion with a rhodium catalyst have been used to support a surface vinyl mechanism for Fischer–Tropsch synthesis. The results were first interpreted by a mechanism that involved a decrease in 13C species on the surface as the carbon number increased. This model is shown to be incorrect. Considering only the 13C-labeled products, the data are consistent with earlier Tracer studies showing that the added 13C2H4 initiates chains.

  • 13C-Tracer Study of the Fischer-Tropsch synthesis : another interpretation
    2000
    Co-Authors: Burtron H. Davis
    Abstract:

    The 13 C-Tracer results from the introduction of 13 C 2 H 4 into syngas prior to conversion with a rhodium catalyst have been used to support a surface vinyl mechanism for Fischer-Tropsch synthesis. The results were first interpreted by a mechanism that involved a decrease in 13 C species on the surface as the carbon number increased. This model is shown to be incorrect. Considering only the 13 C-labeled products, the data are consistent with earlier Tracer studies showing that the added 13 C 2 H 4 initiates chains.

Wan Rohaida Wan Husain - One of the best experts on this subject based on the ideXlab platform.

  • IIUM Tracer Study 2016 follow up
    2017
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Wan Rohaida Wan Husain, Muhammad Karimi Sulaiman
    Abstract:

    The IIUM Tracer Study 2016: Follow Up is the third report of the Tracer Study 2016 project conducted by the International Islamic University Malaysia (IIUM) under the purview of the Alumni and Global Network Division (AGND). This project is a substantial initiative and effort by AGND that receives a strong support from the University to publish a well comprehensive quantitative data report about IIUM’s graduates in collaboration with the Ministry of Higher Education (MOHE). The objective of the survey is to update the employment status of IIUM graduates (Class of 2016). The data was collection 6-months after their graduation (May – October 2017). A total of 4,481 graduates participated in the Study, involving 3,815 First Degree graduates and 666 Postgraduate. The respondents for the Study were the graduates of the 32nd IIUM Convocation. They include; 1. Ahmad Ibrahim Kulliyyah of Laws (AIKOL), 2. IIUM Institute of Islamic Banking and Finance (IIiBF), 3. International Institute of Islamic Thought and Civilisation (ISTAC), 4. International Institute for Halal Research and Training (INHART) 5. Kulliyyah of Allied Health Science (KAHS), 6. Kulliyyah of Architecture and Environmental Design (KAED), 7. Kulliyyah of Dentistry (KOD), 8. Kulliyyah of Engineering (KOE), 9. Kulliyyah of Economics and Management (KENMS), 10. Kulliyyah of Education (KOED), 11. Kulliyyah of Information and Communication Technology (KICT), 12. Kulliyyah of Islamic Revealed Knowledge and Human Sciences (KIRKHS), 13. Kulliyyah of Language and Management (KLM) 14. Kulliyyah of Medicine (KOM), 15. Kulliyyah of Nursing (KON), 16. Kulliyyah of Pharmacy (KOP), and 17. Kulliyyah of Science (KOS). Given that the Tracer Study series have yielded important employment related findings and facts that provide useful information to the University in particular and the nation in general, it is hoped that this particular Report will continue to provide useful, comprehensive and exhaustive information to all, particularly to IIUM and MOHE.

  • IIUM Tracer Study 2016 first degree and post-graduate
    2017
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Mariam Adawiah Dzulkifli, Wan Rohaida Wan Husain
    Abstract:

    Much research has been conducted to Studying graduates’ employability and their pattern of employment after graduation. Research of such nature is known as Tracer Study. The aim of the Tracer Study is to track graduates’ performance or progress after completing their undergraduate/ postgraduate studies. While data on employment among graduates is important, other higher- education related issues are as equally important. A total of 4479 graduates responded to this Study that comprised both of rst- degree graduates and post-graduates. They comprised both undergraduates and postgraduates from all Kulliyyah. They include; 1. Ahmad Ibrahim Kulliyyah of Laws (AIKOL), 2. IIUM Institute of Islamic Banking and Finance (IIiBF), 3. International Institute of Islamic Thought and Civilisation (ISTAC), 4. International Institute for Halal Research and Training (INHART) 5. Kulliyyah of Allied Health Science (KAHS), 6. Kulliyyah of Architecture and Environmental Design (KAED), 7. Kulliyyah of Dentistry (KOD), 8. Kulliyyah of Engineering (KOE), 9. Kulliyyah of Economics and Management (KENMS), 10. Kulliyyah of Education (KOED), 11. Kulliyyah of Information and Communication Technology (KICT), 12. Kulliyyah of Islamic Revealed Knowledge and Human Sciences (KIRKHS), 13. Kulliyyah of Language and Management (KLM) 14. Kulliyyah of Medicine (KOM), 15. Kulliyyah of Nursing (KON), 16. Kulliyyah of Pharmacy (KOP), and 17. Kulliyyah of Science (KOS). An online survey method was adopted in this Study. The instrument used was an online questionnaire prepared by the Alumni and Global Networking Division with cooperation from relevant K/C/D/Is and Information Technology Division. The questionnaire was posted online a month prior to the 32nd convocation ceremony which was held from 5th November to 7th November 2016. The respondents submitted their online questionnaire latest by 5th November 2016.

  • IIUM Tracer Study 2015 follow up
    2016
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Mariam Adawiah Dzulkifli, Aznan Zuhid Saidin, Wan Rohaida Wan Husain
    Abstract:

    The IIUM Tracer Study 2015: Follow Up is the third report of the Tracer Study 2015 project conducted by the International Islamic University Malaysia (IIUM) under the purview of the Alumni and Global Network Division (AGND). This project is a substantial initiative and effort by AGND that receives a strong support from the University to publish a well comprehensive quantitative data report about IIUM’s graduates in collaboration with the Ministry of Higher Education (MOHE). The objective of the survey is to update the employment status of IIUM graduates (Class of 2015). The data was collection 6-months after their graduation (May – October 2016). A total of 4,897 graduates participated in the Study, involving 4,186 First Degree graduates and 711 Postgraduate. The respondents for the Study were the graduates of the 31st IIUM Convocation. They comprised both undergraduates and Postgraduate from all Kulliyyah. They include the Ahmad Ibrahim Kulliyyah of Laws (AIKOL), Human Science (HS), IIUM Institute of Islamic Banking and Finance (IIIBF), Islamic Revealed Knowledge (IRK), International Institute of Islamic Thought and Civilisation (ISTAC), Kulliyyah of Architecture and Environmental Design (KAED), Kulliyyah of Allied Health Science (KAHS), Kulliyyah of Economics and Management (KENMS), Kulliyyah of Information and Communication Technology (KICT), Kulliyyah of Dentistry (KOD), Kulliyyah of Engineering (KOE), Kulliyyah of Education (KOED), Kulliyyah of Medicine (KOM), Kulliyyah of Nursing (KON), Kulliyyah of Pharmacy (KOP) and Kulliyyah of Science (KOS). Given that the Tracer Study series have yielded important employment related findings and facts that provide useful information to the University in particular and the nation in general, it is hoped that this particular Report will continue to provide useful, comprehensive and exhaustive information to all, particularly to IIUM and MOHE.

  • IIUM Tracer Study 2015 first degree and post-graduate
    2016
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Wan Rohaida Wan Husain, Mariam Adawiah Dzulkifli, Aznan Zuhid Saidin
    Abstract:

    The First Degree and Post-Graduate IIUM Tracer Study 2015 Report is the sixteenth Tracer Study project conducted by the International Islamic University Malaysia (IIUM) under the purview of the Alumni and Global Network Division (AGND). This project is a substantial initiative and effort by AGND that receives a strong support from the University to publish a well comprehensive quantitative data report about IIUM’s graduates – both the First Degree and Post-Graduate – in collaboration with the Ministry of Higher Education (MOHE). Given that the Tracer Study series have yielded important employment related findings and facts that provide useful information to the University in particular and the nation in general, it is hoped that this particular Report will continue to provide useful, comprehensive and exhaustive information to all, particularly to IIUM and MOHE. A total of 4,894 graduates participated in the Study, involving 3,599 first-degree graduates and 666 postgraduates. The respondents for the Study were the graduates of the 31st IIUM Convocation. They comprised both undergraduates and postgraduates from all Kulliyyah. They include the Ahmad Ibrahim Kulliyyah of Laws (AIKOL), Human Science (HS), IIUM Institute of Islamic Banking and Finance (IIIBF), Islamic Revealed Knowledge (IRK), International Institute of Islamic Thought and Civilisation (ISTAC), Kulliyyah of Architecture and Environmental Design (KAED), Kulliyyah of Allied Health Science (KAHS), Kulliyyah of Economics and Management (KENMS), Kulliyyah of Information and Communication Technology (KICT), Kulliyyah of Dentistry (KOD), Kulliyyah of Engineering (KOE), Kulliyyah of Education (KOED), Kulliyyah of Medicine (KOM), Kulliyyah of Nursing (KON), Kulliyyah of Pharmacy (KOP) and Kulliyyah of Science (KOS). An online survey method was adopted in this Study. The instrument used was an online questionnaire prepared by the Ministry of Higher Education (MOHE), a standard format used by all participating universities. The MOHE Tracer Study questionnaire comprised seven (7) different sections, which captured information related to the graduates’ (a) background information, (b) evaluation of programmes and services offered by the university/institution, (c) evaluation of effectiveness of Study programme and self-readiness, (d) further studies, (e) current status, (f) employment, and (g) unemployment and others. The questionnaire was posted online a month prior to the 31st convocation ceremony which was held from 7th November to 9th November 2015. The respondents submitted their online questionnaire latest by 15th November 2015. The data were analysed using SPSS. For descriptive statistics, frequency, percentage, mean, standard deviation and cross tabulation were used for the Study.

  • IIUM Tracer Study 2014: follow up
    2015
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Mariam Adawiah Dzulkifli, Aznan Zuhid Saidin, Saodah Abd Rahman, Wan Rohaida Wan Husain
    Abstract:

    IIUM Tracer Study 2014 Follow-Up (IIUMTS2014FU) is a pioneering research project that has been initiated by the Ministry of Education, Malaysia (MOE). The objective of the research is to update the employment status of the university graduates in Malaysia. The sample is the graduates in 2014. The data was collected 6-months after their graduation. The sampling involved a random selection by MOE. The nature of the inquiry was the follow-up questions on the employment status of the graduates from all universities in Malaysia. The methodology was to conduct telephone interview to the sample based on the name list provided by MOE. The research managed to collect a total of 300 graduates via phone interview and online survey. IIUMTS2014FU was commenced in April 2015. The pre-set questions of MOE were in Malay language (Bahagian A - G). It was checked and modified by the researchers prior to the data collection stage. The modification was done not to change the questions but to better fit to the nature of IIUM students so that the data collection process would run smoothly. A mock interview session was conducted on three graduates for practical rehearsal and for validation purposes. The real interview session took about 20 minutes to complete. Among the topic coverage of IIUMTS2014FU are the graduates' current employment status, main occupation group, job status, monthly income and employment sector

Rohaiza Abd. Rokis - One of the best experts on this subject based on the ideXlab platform.

  • IIUM Tracer Study 2016 follow up
    2017
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Wan Rohaida Wan Husain, Muhammad Karimi Sulaiman
    Abstract:

    The IIUM Tracer Study 2016: Follow Up is the third report of the Tracer Study 2016 project conducted by the International Islamic University Malaysia (IIUM) under the purview of the Alumni and Global Network Division (AGND). This project is a substantial initiative and effort by AGND that receives a strong support from the University to publish a well comprehensive quantitative data report about IIUM’s graduates in collaboration with the Ministry of Higher Education (MOHE). The objective of the survey is to update the employment status of IIUM graduates (Class of 2016). The data was collection 6-months after their graduation (May – October 2017). A total of 4,481 graduates participated in the Study, involving 3,815 First Degree graduates and 666 Postgraduate. The respondents for the Study were the graduates of the 32nd IIUM Convocation. They include; 1. Ahmad Ibrahim Kulliyyah of Laws (AIKOL), 2. IIUM Institute of Islamic Banking and Finance (IIiBF), 3. International Institute of Islamic Thought and Civilisation (ISTAC), 4. International Institute for Halal Research and Training (INHART) 5. Kulliyyah of Allied Health Science (KAHS), 6. Kulliyyah of Architecture and Environmental Design (KAED), 7. Kulliyyah of Dentistry (KOD), 8. Kulliyyah of Engineering (KOE), 9. Kulliyyah of Economics and Management (KENMS), 10. Kulliyyah of Education (KOED), 11. Kulliyyah of Information and Communication Technology (KICT), 12. Kulliyyah of Islamic Revealed Knowledge and Human Sciences (KIRKHS), 13. Kulliyyah of Language and Management (KLM) 14. Kulliyyah of Medicine (KOM), 15. Kulliyyah of Nursing (KON), 16. Kulliyyah of Pharmacy (KOP), and 17. Kulliyyah of Science (KOS). Given that the Tracer Study series have yielded important employment related findings and facts that provide useful information to the University in particular and the nation in general, it is hoped that this particular Report will continue to provide useful, comprehensive and exhaustive information to all, particularly to IIUM and MOHE.

  • IIUM Tracer Study 2016 first degree and post-graduate
    2017
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Mariam Adawiah Dzulkifli, Wan Rohaida Wan Husain
    Abstract:

    Much research has been conducted to Studying graduates’ employability and their pattern of employment after graduation. Research of such nature is known as Tracer Study. The aim of the Tracer Study is to track graduates’ performance or progress after completing their undergraduate/ postgraduate studies. While data on employment among graduates is important, other higher- education related issues are as equally important. A total of 4479 graduates responded to this Study that comprised both of rst- degree graduates and post-graduates. They comprised both undergraduates and postgraduates from all Kulliyyah. They include; 1. Ahmad Ibrahim Kulliyyah of Laws (AIKOL), 2. IIUM Institute of Islamic Banking and Finance (IIiBF), 3. International Institute of Islamic Thought and Civilisation (ISTAC), 4. International Institute for Halal Research and Training (INHART) 5. Kulliyyah of Allied Health Science (KAHS), 6. Kulliyyah of Architecture and Environmental Design (KAED), 7. Kulliyyah of Dentistry (KOD), 8. Kulliyyah of Engineering (KOE), 9. Kulliyyah of Economics and Management (KENMS), 10. Kulliyyah of Education (KOED), 11. Kulliyyah of Information and Communication Technology (KICT), 12. Kulliyyah of Islamic Revealed Knowledge and Human Sciences (KIRKHS), 13. Kulliyyah of Language and Management (KLM) 14. Kulliyyah of Medicine (KOM), 15. Kulliyyah of Nursing (KON), 16. Kulliyyah of Pharmacy (KOP), and 17. Kulliyyah of Science (KOS). An online survey method was adopted in this Study. The instrument used was an online questionnaire prepared by the Alumni and Global Networking Division with cooperation from relevant K/C/D/Is and Information Technology Division. The questionnaire was posted online a month prior to the 32nd convocation ceremony which was held from 5th November to 7th November 2016. The respondents submitted their online questionnaire latest by 5th November 2016.

  • IIUM Tracer Study 2015 follow up
    2016
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Mariam Adawiah Dzulkifli, Aznan Zuhid Saidin, Wan Rohaida Wan Husain
    Abstract:

    The IIUM Tracer Study 2015: Follow Up is the third report of the Tracer Study 2015 project conducted by the International Islamic University Malaysia (IIUM) under the purview of the Alumni and Global Network Division (AGND). This project is a substantial initiative and effort by AGND that receives a strong support from the University to publish a well comprehensive quantitative data report about IIUM’s graduates in collaboration with the Ministry of Higher Education (MOHE). The objective of the survey is to update the employment status of IIUM graduates (Class of 2015). The data was collection 6-months after their graduation (May – October 2016). A total of 4,897 graduates participated in the Study, involving 4,186 First Degree graduates and 711 Postgraduate. The respondents for the Study were the graduates of the 31st IIUM Convocation. They comprised both undergraduates and Postgraduate from all Kulliyyah. They include the Ahmad Ibrahim Kulliyyah of Laws (AIKOL), Human Science (HS), IIUM Institute of Islamic Banking and Finance (IIIBF), Islamic Revealed Knowledge (IRK), International Institute of Islamic Thought and Civilisation (ISTAC), Kulliyyah of Architecture and Environmental Design (KAED), Kulliyyah of Allied Health Science (KAHS), Kulliyyah of Economics and Management (KENMS), Kulliyyah of Information and Communication Technology (KICT), Kulliyyah of Dentistry (KOD), Kulliyyah of Engineering (KOE), Kulliyyah of Education (KOED), Kulliyyah of Medicine (KOM), Kulliyyah of Nursing (KON), Kulliyyah of Pharmacy (KOP) and Kulliyyah of Science (KOS). Given that the Tracer Study series have yielded important employment related findings and facts that provide useful information to the University in particular and the nation in general, it is hoped that this particular Report will continue to provide useful, comprehensive and exhaustive information to all, particularly to IIUM and MOHE.

  • IIUM Tracer Study 2015 first degree and post-graduate
    2016
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Wan Rohaida Wan Husain, Mariam Adawiah Dzulkifli, Aznan Zuhid Saidin
    Abstract:

    The First Degree and Post-Graduate IIUM Tracer Study 2015 Report is the sixteenth Tracer Study project conducted by the International Islamic University Malaysia (IIUM) under the purview of the Alumni and Global Network Division (AGND). This project is a substantial initiative and effort by AGND that receives a strong support from the University to publish a well comprehensive quantitative data report about IIUM’s graduates – both the First Degree and Post-Graduate – in collaboration with the Ministry of Higher Education (MOHE). Given that the Tracer Study series have yielded important employment related findings and facts that provide useful information to the University in particular and the nation in general, it is hoped that this particular Report will continue to provide useful, comprehensive and exhaustive information to all, particularly to IIUM and MOHE. A total of 4,894 graduates participated in the Study, involving 3,599 first-degree graduates and 666 postgraduates. The respondents for the Study were the graduates of the 31st IIUM Convocation. They comprised both undergraduates and postgraduates from all Kulliyyah. They include the Ahmad Ibrahim Kulliyyah of Laws (AIKOL), Human Science (HS), IIUM Institute of Islamic Banking and Finance (IIIBF), Islamic Revealed Knowledge (IRK), International Institute of Islamic Thought and Civilisation (ISTAC), Kulliyyah of Architecture and Environmental Design (KAED), Kulliyyah of Allied Health Science (KAHS), Kulliyyah of Economics and Management (KENMS), Kulliyyah of Information and Communication Technology (KICT), Kulliyyah of Dentistry (KOD), Kulliyyah of Engineering (KOE), Kulliyyah of Education (KOED), Kulliyyah of Medicine (KOM), Kulliyyah of Nursing (KON), Kulliyyah of Pharmacy (KOP) and Kulliyyah of Science (KOS). An online survey method was adopted in this Study. The instrument used was an online questionnaire prepared by the Ministry of Higher Education (MOHE), a standard format used by all participating universities. The MOHE Tracer Study questionnaire comprised seven (7) different sections, which captured information related to the graduates’ (a) background information, (b) evaluation of programmes and services offered by the university/institution, (c) evaluation of effectiveness of Study programme and self-readiness, (d) further studies, (e) current status, (f) employment, and (g) unemployment and others. The questionnaire was posted online a month prior to the 31st convocation ceremony which was held from 7th November to 9th November 2015. The respondents submitted their online questionnaire latest by 15th November 2015. The data were analysed using SPSS. For descriptive statistics, frequency, percentage, mean, standard deviation and cross tabulation were used for the Study.

  • IIUM Tracer Study 2014: follow up
    2015
    Co-Authors: Rohaiza Abd. Rokis, Shukran Abdul Rahman, Ainol Madziah Zubairi, Mohd. Feham Ghalib, Tunku Mohar Tunku Mohd Mokhtar, Mohd Yazid Zul Kepli, Mariam Adawiah Dzulkifli, Aznan Zuhid Saidin, Saodah Abd Rahman, Wan Rohaida Wan Husain
    Abstract:

    IIUM Tracer Study 2014 Follow-Up (IIUMTS2014FU) is a pioneering research project that has been initiated by the Ministry of Education, Malaysia (MOE). The objective of the research is to update the employment status of the university graduates in Malaysia. The sample is the graduates in 2014. The data was collected 6-months after their graduation. The sampling involved a random selection by MOE. The nature of the inquiry was the follow-up questions on the employment status of the graduates from all universities in Malaysia. The methodology was to conduct telephone interview to the sample based on the name list provided by MOE. The research managed to collect a total of 300 graduates via phone interview and online survey. IIUMTS2014FU was commenced in April 2015. The pre-set questions of MOE were in Malay language (Bahagian A - G). It was checked and modified by the researchers prior to the data collection stage. The modification was done not to change the questions but to better fit to the nature of IIUM students so that the data collection process would run smoothly. A mock interview session was conducted on three graduates for practical rehearsal and for validation purposes. The real interview session took about 20 minutes to complete. Among the topic coverage of IIUMTS2014FU are the graduates' current employment status, main occupation group, job status, monthly income and employment sector

P. Skeldon - One of the best experts on this subject based on the ideXlab platform.

  • Tracer Study of pore initiation in anodic alumina formed in phosphoric acid
    Electrochimica Acta, 2013
    Co-Authors: A Baronwiechec, P. Skeldon, Hiroki Habazaki, G.e. Thompson, M G Burke, T Hashimoto, J J Ganem, I Vickridge
    Abstract:

    Abstract Arsenic species are utilized as Tracers in a Study of pore initiation in anodic films that were formed at constant potentials on aluminium in phosphoric acid. The films were grown first in sodium arsenate solution and then in phosphoric acid, and examined using ion beam analysis and scanning and transmission electron microscopies. The analysis of the arsenic content of specimens indicates that the growth mechanisms of incipient and major pores involve mainly field-assisted dissolution and field-assisted flow of the alumina, respectively. The transition between incipient and major pore formation is suggested to be initiated by preferential growth of certain incipient pores, leading to a locally increased current density at the pore bases. The major pores subsequently develop by the flow oxide away from the pore bases, which is evident from the behaviour of the arsenic Tracer. The results suggest that the flow is associated with the non-uniform distribution of ionic current and a relatively low volume of formed film material compared with the volume of oxidized aluminium.

  • 18 o Tracer Study of porous film growth on aluminum in phosphoric acid
    Journal of The Electrochemical Society, 2010
    Co-Authors: A Baronwiechec, P. Skeldon, G.e. Thompson, S J Garciavergara, J J Ganem, I Vickridge
    Abstract:

    (18)O Tracer is used to investigate the development of porous anodic films at constant current in phosphoric acid on electropolished aluminum. A barrier layer and porous region form initially with the pore size related to the surface texture of the substrate. Subsequently, major pores emerge, with their sizes related to the anodizing voltage. The evolution of the film is accompanied by increases in growth rate and formation efficiency. The (18)O ions of a preformed oxide are retained in the film during anodization in a nonenriched electrolyte, with (18)O being partitioned among (i) the surface region of texture-dependent porosity, (ii) the walls of major pores, and, in diminishing amounts, (iii) the inner region of the barrier layer. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3490640] All rights reserved.

  • a Tracer Study of porous anodic alumina
    Electrochemical and Solid State Letters, 2006
    Co-Authors: P. Skeldon, G.e. Thompson, S J Garciavergara, L Iglesiasrubianes, C E Blancopinzon
    Abstract:

    The present Study employs a tungsten Tracer incorporated into the aluminum substrate to investigate the development of porosity in anodic alumina formed in phosphoric acid electrolyte. An unusual inversion of the Tracer distribution is revealed as the Tracer layer traverses the barrier region. Although initially incorporated into the barrier layer at locations beneath pore bases, associated with the scalloped metal/oxide interface, the Tracer at these locations subsequently lags behind that found at the cell walls. The behavior is contrary to expectations of a field-assisted dissolution model of pore development, with usual migration behaviors of film species in the barrier layer. However, the findings are consistent with pore formation due mainly to flow of alumina from the barrier layer toward the cell walls, driven by film growth stresses. Flow of film material can also account for the presence of phosphorus species in the film and the increased thickness of the film relative to that of the oxidized metal. Anodic alumina films are used extensively in protection and functionalization of aluminum alloys, in electronics through aerospace to architecture. The films are usually formed in aqueous electrolytes, with two morphological types recognized that depend upon composition of the electrolyte, pH, current density, voltage, temperature, etc. Fig. 1. 1-4 Barrier films consist of compact, amorphous alumina of uniform thickness, up to a few hundred nanometers. Porous films comprise a thin barrier layer next to the metal and an outer layer of porous alumina, up to tens of m thick. 2,3 The pores are of approximately cylindrical section and extend from the film surface to the barrier layer. The thickness of the barrier layer and the diameter of the pores are related to the forming voltage, with ratios of 1n m V 1 , while the thickness of the porous layer depends primarily upon the anodizing charge for a particular current density. The porosity has often been explained by massively increased dissolution of the alumina at the pore base under the high electric field of the barrier layer. 5 An early suggestion was made of a role of oxide flow in the dissolution process, with flow occurring due to electrostriction stresses, estimated to be of the order 100 MPa and sufficient to deform oxides. 6

  • A Tracer Study of Oxide Growth during Spark Anodizing of Aluminum
    Journal of The Electrochemical Society, 2006
    Co-Authors: F. Monfort, P. Skeldon, A. Berkani, Endzhe Matykina, Hiroki Habazaki, G.e. Thompson, K. Shimizu
    Abstract:

    Sequential anodizing is employed to investigate the mechanism of coating growth on aluminum under sparking in a phosphate electrolyte. Thus, coatings are formed in a silicate electrolyte and then in the phosphate electrolyte, with the location of phosphorus in the final coating being identified by electron probe microanalysis. The presence of silicon primarily in the outer region of the coating and of phosphorus primarily in the inner region of the coating indicates short-circuit transport of phosphorus species through the coating, with new coating material being formed in the vicinity of the metal/coating interface. The transport path is presumed to be associated with pores, cracks, and channels in the coating produced by dielectric breakdown events. © 2005 The Electrochemical Society. All rights reserved.

  • a Tracer Study of oxide growth during spark anodizing of aluminum
    Journal of The Electrochemical Society, 2005
    Co-Authors: F. Monfort, P. Skeldon, A. Berkani, Endzhe Matykina, Hiroki Habazaki, G.e. Thompson, K. Shimizu
    Abstract:

    Sequential anodizing is employed to investigate the mechanism of coating growth on aluminum under sparking in a phosphate electrolyte. Thus, coatings are formed in a silicate electrolyte and then in the phosphate electrolyte, with the location of phosphorus in the final coating being identified by electron probe microanalysis. The presence of silicon primarily in the outer region of the coating and of phosphorus primarily in the inner region of the coating indicates short-circuit transport of phosphorus species through the coating, with new coating material being formed in the vicinity of the metal/coating interface. The transport path is presumed to be associated with pores, cracks, and channels in the coating produced by dielectric breakdown events.

G.e. Thompson - One of the best experts on this subject based on the ideXlab platform.

  • Tracer Study of pore initiation in anodic alumina formed in phosphoric acid
    Electrochimica Acta, 2013
    Co-Authors: A Baronwiechec, P. Skeldon, Hiroki Habazaki, G.e. Thompson, M G Burke, T Hashimoto, J J Ganem, I Vickridge
    Abstract:

    Abstract Arsenic species are utilized as Tracers in a Study of pore initiation in anodic films that were formed at constant potentials on aluminium in phosphoric acid. The films were grown first in sodium arsenate solution and then in phosphoric acid, and examined using ion beam analysis and scanning and transmission electron microscopies. The analysis of the arsenic content of specimens indicates that the growth mechanisms of incipient and major pores involve mainly field-assisted dissolution and field-assisted flow of the alumina, respectively. The transition between incipient and major pore formation is suggested to be initiated by preferential growth of certain incipient pores, leading to a locally increased current density at the pore bases. The major pores subsequently develop by the flow oxide away from the pore bases, which is evident from the behaviour of the arsenic Tracer. The results suggest that the flow is associated with the non-uniform distribution of ionic current and a relatively low volume of formed film material compared with the volume of oxidized aluminium.

  • 18 o Tracer Study of porous film growth on aluminum in phosphoric acid
    Journal of The Electrochemical Society, 2010
    Co-Authors: A Baronwiechec, P. Skeldon, G.e. Thompson, S J Garciavergara, J J Ganem, I Vickridge
    Abstract:

    (18)O Tracer is used to investigate the development of porous anodic films at constant current in phosphoric acid on electropolished aluminum. A barrier layer and porous region form initially with the pore size related to the surface texture of the substrate. Subsequently, major pores emerge, with their sizes related to the anodizing voltage. The evolution of the film is accompanied by increases in growth rate and formation efficiency. The (18)O ions of a preformed oxide are retained in the film during anodization in a nonenriched electrolyte, with (18)O being partitioned among (i) the surface region of texture-dependent porosity, (ii) the walls of major pores, and, in diminishing amounts, (iii) the inner region of the barrier layer. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3490640] All rights reserved.

  • a Tracer Study of porous anodic alumina
    Electrochemical and Solid State Letters, 2006
    Co-Authors: P. Skeldon, G.e. Thompson, S J Garciavergara, L Iglesiasrubianes, C E Blancopinzon
    Abstract:

    The present Study employs a tungsten Tracer incorporated into the aluminum substrate to investigate the development of porosity in anodic alumina formed in phosphoric acid electrolyte. An unusual inversion of the Tracer distribution is revealed as the Tracer layer traverses the barrier region. Although initially incorporated into the barrier layer at locations beneath pore bases, associated with the scalloped metal/oxide interface, the Tracer at these locations subsequently lags behind that found at the cell walls. The behavior is contrary to expectations of a field-assisted dissolution model of pore development, with usual migration behaviors of film species in the barrier layer. However, the findings are consistent with pore formation due mainly to flow of alumina from the barrier layer toward the cell walls, driven by film growth stresses. Flow of film material can also account for the presence of phosphorus species in the film and the increased thickness of the film relative to that of the oxidized metal. Anodic alumina films are used extensively in protection and functionalization of aluminum alloys, in electronics through aerospace to architecture. The films are usually formed in aqueous electrolytes, with two morphological types recognized that depend upon composition of the electrolyte, pH, current density, voltage, temperature, etc. Fig. 1. 1-4 Barrier films consist of compact, amorphous alumina of uniform thickness, up to a few hundred nanometers. Porous films comprise a thin barrier layer next to the metal and an outer layer of porous alumina, up to tens of m thick. 2,3 The pores are of approximately cylindrical section and extend from the film surface to the barrier layer. The thickness of the barrier layer and the diameter of the pores are related to the forming voltage, with ratios of 1n m V 1 , while the thickness of the porous layer depends primarily upon the anodizing charge for a particular current density. The porosity has often been explained by massively increased dissolution of the alumina at the pore base under the high electric field of the barrier layer. 5 An early suggestion was made of a role of oxide flow in the dissolution process, with flow occurring due to electrostriction stresses, estimated to be of the order 100 MPa and sufficient to deform oxides. 6

  • A Tracer Study of Oxide Growth during Spark Anodizing of Aluminum
    Journal of The Electrochemical Society, 2006
    Co-Authors: F. Monfort, P. Skeldon, A. Berkani, Endzhe Matykina, Hiroki Habazaki, G.e. Thompson, K. Shimizu
    Abstract:

    Sequential anodizing is employed to investigate the mechanism of coating growth on aluminum under sparking in a phosphate electrolyte. Thus, coatings are formed in a silicate electrolyte and then in the phosphate electrolyte, with the location of phosphorus in the final coating being identified by electron probe microanalysis. The presence of silicon primarily in the outer region of the coating and of phosphorus primarily in the inner region of the coating indicates short-circuit transport of phosphorus species through the coating, with new coating material being formed in the vicinity of the metal/coating interface. The transport path is presumed to be associated with pores, cracks, and channels in the coating produced by dielectric breakdown events. © 2005 The Electrochemical Society. All rights reserved.

  • a Tracer Study of oxide growth during spark anodizing of aluminum
    Journal of The Electrochemical Society, 2005
    Co-Authors: F. Monfort, P. Skeldon, A. Berkani, Endzhe Matykina, Hiroki Habazaki, G.e. Thompson, K. Shimizu
    Abstract:

    Sequential anodizing is employed to investigate the mechanism of coating growth on aluminum under sparking in a phosphate electrolyte. Thus, coatings are formed in a silicate electrolyte and then in the phosphate electrolyte, with the location of phosphorus in the final coating being identified by electron probe microanalysis. The presence of silicon primarily in the outer region of the coating and of phosphorus primarily in the inner region of the coating indicates short-circuit transport of phosphorus species through the coating, with new coating material being formed in the vicinity of the metal/coating interface. The transport path is presumed to be associated with pores, cracks, and channels in the coating produced by dielectric breakdown events.