Senior Application Scientist
Dr. Yunes received his B.S. degree in Chemistry from the Central University of Venezuela. He received both his M.S. and Ph.D. degrees in Physical Chemistry from Catholic University of Louvain, Louvain-La-Neuve, Belgium, with “La Plus Grande Distinction,” the highest honor to be granted by the University. His Ph.D. thesis was carried out under the supervision of Prof. Bernard Delmon, worldwide authority in the field of catalysis.
Dr. Yunes is recognized worldwide for his contribution to the field of adsorption and the application of adsorption techniques to the characterization of solids, particularly catalysts.
During his studies in Belgium, Dr. Yunes was able to synthesize hydrotreating (HDT) catalysts from natural laterite and bauxite (naturally abundant in Venezuela) to efficiently remove impurities from Venezuelan heavy crude oil and lengthen the life of the classical catalysts used in such a process. His knowledge and interest in adsorption began at that time. All the synthesized catalysts were characterized using adsorption techniques for both physical adsorption, to study structure, and chemisorption, to determine the active metal dispersion of the catalysts.
Dr. Yunes joined Micromeritics in May 1984, where he held the position of Senior Application Scientist, conducting experiments on adsorption, assisting the development of new products and writing application notes. His primary function at Micromeritics was to support customers worldwide with their applications, and to find or assist in developing new technologies to meet the needs of customers.
From 1992 to 1996 Dr. Yunes managed a Micromeritics laboratory at the Venezuelan Research Institute (IVIC) in Caracas, Venezuela. This position was dedicated to assisting under-graduate and post-graduate students in characterizing their catalysts and to support their research for attaining their degrees.
From 2004 to 2009 Dr. Yunes supervised the Catalyst Characterization Laboratory at the Venezuelan Petroleum Institute INTEVEP, serving all national refineries belonging to PDVSA, the Venezuelan National Oil Company.
In September 2009, Dr. Yunes returned to the Micromeritics headquarters in Norcross, Ga, where his primary responsibility is the support of customers worldwide in their application of Micromeritics technologies.
Dr. Yunes has given more than 150 presentations and seminars around the world in many languages. He speaks six languages, and he is a co-author of the Micromeritics book Analytical Methods in Fine Particle Technology.
o "Automne Course", Aussois, France, organized by the National Council for Scientific Research (CNRS) on the Study of Surface Solid Phenomena. Sept. 26, 1980
o The International Symposium organized by Prof. Rouquerol and Prof. Sing. Aix-en-Provence, France. On The Adsorption of Gas-Solid and Liquid-Liquid Interfaces. Sept. 21, 1981
o Training course organized by Dr. Jacquin on: The use of some equipment for the study of Solid Mechanical Resistance. Institut Français du Pétrole. Sept. 16, 1982
o The NATO Advanced Study Institute on: Surface Properties and Catalysis by non-metal Oxides, Sulfides and other Transition Metal Compounds. Lille, France. Sept. 20, 1982
o Training Course on: The use of Micromeritics Instruments for Physisorption and Chemisorption Analysis. May 26, 1983
o Training in the use of Operation of Catalysts Cracking Unit "MAT" W.R. Grace-Davison. Baltimore MD, USA. June 1982
o Heterogeneous Catalysis organized by the University of Houston. April 5-10, 1990
Dr. Yunes is author, or co-author, of more than 30 technical publications, including:
1) J. Laine, J. Brito and S. Yunes. The Surface acidity of The Promoted MoO3/Al2O3 Catalyts. IIIInternational Congress on: The Use of Chemical Molybdenum. Michigan, USA. PP.111, 1970
2) J. Laine, J. Brito, and S.Yunes. The Effect of Nickel on The Acidity and Hydrodesulfurization Activity of Supported Molybdate Catalysts. ACS. San Francisco, USA. pp. 438(3). August, 1980
3) P. Andreu, A. Ayerbe, J. Laine and S. Yunes. Surface Acidity of Hydrodesulfurization Catalysts. 7th. Symposium Iberoamericano de Catalisis, La Plata, Argentina. July, 13-18, 1980
4) J. Laine, S. Yunes, J. Brito and P. Andreu., Relationship between the Number and Strength of the Acid Sites on Solid Surface Using Ammonia Adsorption., J. Catalysis, 157-160, 62, 1980
5) J. Laine, S. Yunes and P. Andreu., Evaluation of the Correlation between Acidity and Acid Strength Using Ammonia Adsorption. AsoVac Meeting, Maracay, Venezuela, 1978
6) J. Laine, J. Brito, S.Yunes and E. Gonzalez. Effects of the Metallic Contents and Sulfidation on the Acid of NiMo SupportedCatalysts.AsoVac Meeting. Barquisimeto, Venezuela, 1979
7) J. Laine, J. Blanco, C. Villamizar, S. Yunes and J. Brito. New Method for the Preparation of HDS Catalysts, Patent Pending. Ministerio de Fomento, Venezuela
8) J. Laine, J. Brito and S.Yunes. On the Role of Nickel in Hydrodesulfurization Catalysts. J. Chem. Tech. Biotech., 33A, 227-231, 1983
9) J. Laine, J. Brito, S.Yunes and P. Andreu. AcidStrength Distribution in the Mo-Al-Si and Ni-Mo-Al Oxides Systems by Ammonia Adsorption. Reaction Kinetics and Catalysis Letters, pp.514, 1984
10) S. Yunes, A. Sherwood and J. Smithwick. Chemisorption: Its Definition, Advantage and Application in Economical Production and Uses of Catalysts. 8th. National Symposium, Dhambad, Bihar, India, 1987
11) S.Yunes, R. Maley, H. Stanley and R Johnson. Surface Area and Pore Size Distribution by a New Accelerated Nitrogen Adsorption Analyzer. IUPAC, Bad Soden, Fed. Rep.of Germany, April 26, 1987
12) J. Brito, S.Yunes and J. Laine,. Effects of the COTreatment of the Promoter Itself on Copper and Chromium as Non-Supported Catalysts. Symposium Iberoamericano de Catalisis, Merida, Venezuela. August 1986
13) S. Yunes, P. Grange , M. Oves, H. Stanley and B. Delmon., Study of the Behavior of Iron on Hydrotreatment Catalyst. Symposio Iberoamericano de Catalisis, Merida, Venezuela. August, 1986
14) S.Yunes, R. Prada, A. Arteaga, P. Grange and B. Delmon. The Influence of the Reoxidation and Sulfurization Temperature on the Active Phase Dispersion on HDS Catalysts. Correlation between Chemisorption of Probe Molecules and XPS. 3rd. Symposium on Catalysis. Bahia, Brasil, August 1985
15) C.S. O'Neil, S. Yunes and C. Orr. An Automated Method for the Determination of Pore Size and Pore Shape Distribution by Mercury Porosimetry. Pittsburgh Conference, Atlantic City, USA. March 1986
16) S.Yunesand C. O'Neil. A comparison of Nitrogen and Oxygen of Adsorption Data on Micropore Solids. The 5th International Conference on Surface and Colloids. Clarkson University, Postdam, N.Y., June 24-28, 1985
17) S.Yunes, P.Grange, A. Herbillon and B. Delmon. Identification and Characterization of Natural Laterite. The 6th Euroclay Symposium, Seville, Spain, 1987
18) S.Yunes, D.S . Thakur, P. Grange and B. Delmon. Influence of Calcination Temperature on the Texture of Laterite. The 6th Euroclay Symposium, Seville, Spain, 1987
19) S. Yunes, D.S. Thakur, P.Grange and B. Delmon. Laterite as a Catalyst for the Hydrotreatment of Heavy Oil. I: Identification and Characterization of a Venezuelan Laterite. Bull. Soc. Chim. Belge. Vol.97, No.11-12, PP.831, 1988
20) S.Yunes, D.S. Thakur, P. Grange and B. Delmon. Laterite as a Catalyst for the Hydrotreatment ofHeavy Oil. II: Influence of Chemical and Thermal Treatments on The HDS and HDM Activity. Bull. Soc. Chim. Belge. Vol.97, No.11-12, PP.841, 1988
21) A. Thornton, S. Yunes, J. Bienemann and B. Conklin. Mercury Porosimetry Analysis Performed with Combined High Sample Throughput and Ensured Pore Volume Resolution. Partikle Technologie, Nurnberg. Federal Republic of Germany, April 19-21, 1989
22) S. Yunes, D.S. Thakur, P. Grange and B. Delmon. Preparation, Physico Chemical Characterization and Catalytic Activity of Iron-based Hydrotreating Catalysts. Catalysts in Petroleum Refining . Kuwait, March 5-8, pp.317, 1989
23) A. Corma, F. Melo, A. Mifsud and S. Yunes. Study with Different Adsorbents of the Microporosity in Dealuminated Zeolites. IUPAC. Alicante, Spain. May , 1990
24) S. Yunes, R. Prada Silvy, A. Arteaga, P. Grange and B. Delmon. 3th Meeting on Catalysis, Instituto Brasilero de Petroleo., Rio de Janeiro, Brasil. pp.224, 1985
o The Venezuelan Institute of Scientific Research "IVIC" as a research student. Three years of research conducted with Dr. J. Laine,1975-1978.
o The National Hydrocarbon Funds of Venezuela "FONINVES" for postgraduate studies conducted in Belgium.