Who We Are

We Are The Particle Testing Authority

We specialize in the characterization of fine powders and solid material. With more than 55 years of experience, we have earned an excellent reputation in the particle and materials characterization field and continue striving to excel in our knowledge and service toward our customers.


Our roots come from Micromeritics Instrument Corporation, and we have not ceased to work very closely with the esteemed scientists and engineers of Micromeritics.   In recent years we have started to work with many other suppliers of analytical equipment which complement our established technologies and allow us to better serve our customers’ needs.   Our suppliers and partners include Malvern Instruments, Surface Measurement Systems, TA Instruments, Particle Sizing Systems, Phenom World, and Zeiss microscopes.  In addition to this, Micromeritics’ 2018 acquisitions of Freeman Technologies and PID Tech & Eng. have expanded our capabilities and expertise in powder flow rheology with the FT4 and catalytic studies with the Effi Microreactor.


Moreover, we have formed a network of labs which are highly reputable and qualified in their specific areas.  Working with so many industry leading instrumentation suppliers and laboratory service providers allows us to offer the best and broadest solutions possible to even the most challenging problems.


Nevertheless, the most important asset for any company is its employees, and at Particle Testing Authority every member of our team has a unique contribution to our world-class service.

Greg Thiele

General Manager

Thao Gastaldo

Laboratory Manager

Mansi Patel

Quality Manager

Tamara Davis

Lab Coordinator

Bryan Shaw

Sales Engineer

Jan Gifford

Lab AR

Henry Forrest

Quality Assurance Associate

Jacek Jagiello

Senior Scientist

Jeff Kenvin

Group Leader, Scientific Services Group

Tony Thornton

Director of Technical Information

Simon Yunes

Senior Scientist

Ping Guo

Technology & Applications Consultant

Jack Saad

Associate Scientist

Chris Brown

Lab Analyst II

Pearl Kwon

Lab Analyst II

Jacob Goodman

Lab Analyst I

Israel Tordoya

Lab Analyst I

Hoang Nguyen

Lab Analyst II

Sanissa Xayamounkhoun

Lab Analyst I

Katharina Peikert

Scientific Services Europe

Torben Sick

European Laboratory Manager

Greg Thiele - General Manager

Greg has worked in the material characterization field more than 23 years and has a deep understanding of the techniques used at Particle Testing Authority and how they apply to the different industries and applications. Greg currently serves as the General Manager for all Lab Services, including our labs in Norcross, Houston, Aachen Germany, and Shanghai China.

Thao Gastaldo - Laboratory Manager

Thao Gastaldo has been with Micromeritics since May 2008.  She graduated from Georgia Tech with a BS in Biology.  Thao has had a few different roles since she began working in the lab.  She started out as a Lab Analyst then transitioned to Lab Compliance Specialist, Quality Assurance Manager, and her current position is as Lab Manager.  Thao is responsible for overseeing the day to day operations of the lab and ensuring everything runs smoothly.

Mansi Patel - Quality Manager

Mansi Patel has received her degree in Pharmaceutical Science from Campbell University, NC.  She has been working in the Quality Assurance field for more than 10 years and has recently joined Micromeritics in March 2018.  Mansi is responsible for the overall Quality Management System. In her free time, she likes to watch movies, paint with her daughters, and create memories with her family.

Tamara Davis - Lab Coordinator

“Promoting Excellent Customer service to our clients with our growing company.”

Tamara Davis moved from Orlando, Florida to Duluth , Georgia about 2 years ago to pursue new endeavors. She is currently studying to get her business degree at Southern New Hampshire University. She is a registered pharmacy technician and very passionate about helping our customers. Tamara loves going shopping and being a dedicated cheer Mom for her daughter. Tamara is eager to assist our customers with all their business needs.

Bryan Shaw - Sales Engineer

Bryan recently joined Particle Testing Authority as a sales and customer service engineer.  He is a graduate of Georgia Tech and has spent much of his time since graduation in labs working on various applications within the polymer industry.   Bryan also has experience as a project manager in the materials characterization industry at FAI Materials Testing Services.   He has a passion for connecting with the people he meets and is driven to add value to each of his relationships.  We are excited to have Bryan join our team, and he will be a valuable resource to customers.  

Jeff Kenvin - Group Leader, Scientific Services Group

Dr. Kenvin received his B.S. degree in Chemical Engineering from Drexel University in Philadelphia , Pa. He received his Ph.D. degree in Chemical Engineering from the Georgia Institute of Technology in Atlanta, Ga.

His areas of expertise are in the characterization of porous materials and catalysts using physical and chemical adsorption and in mercury porosimetry.

While employed by the Mobil Research and Development Company as a member of the Mobil Lubes – Process and Products Research Division, Dr. Kenvin managed research and development projects involving the commercialization of new hydrotreated base oils. He was the innovator of the use of chemometrics to define base oil quality standards. These chemometric models subsequently led to the development and implementation of novel techniques for characterizing composition and optimizing refinery lube operations, and the technology was successfully implemented in all Mobil lube refineries. In 1994, Dr. Kenvin received the Products Division – Technology Award for his contribution to the Mobil Corporation.

Later, as a member of the Hoechst A.G. North America Next Generation Process-Polymer Group, Dr. Kenvin directed leveraged-research at the Georgia Institute of Technology. His research involved the identification of new technologies for the process and development of low-cost terephthalic acid and novel monomers for improving the properties of PET (polyester terephthalate), including the application of super-acid catalysis for the carbonylation of toluene.

Dr. Kenvin has been invited to present scientific lectures at more than 100 seminars and regularly participates in short courses on particle technology. He also serves on international advisory boards and is an officer of the ASTM D-32 committee on catalysis.

Tony Thornton - Director of Technical Information

Anthony W. Thornton received both his B.S. degree in Chemistry (cum laude) and his M.S. degree in Analytical Chemistry from Emory University in Atlanta, in 1980.

Tony’s research at Emory involved liquid chromatography, specifically the use of ion-pair chromatography and isocratic separation of catecholamines and metabolites. His work supported early research into potential treatment of Parkinson’s disease between Emory and the Veterans Administration hospital in Atlanta.

By 1983, Tony’s work with liquid chromatography evolved into the study of particle sizing using liquid chromatography, specifically using a technique known as Hydrodynamic Chromatography. His work involved the packing of columns where separation occurs and the co-development of Micromeritics’ first use of the Non-negative Least Squares deconvolution method, later used with Laser Light Scattering and Non-Local Density Functional Theory (NLDFT).

As Micromeritics developed its suite of particle size analysis instrumentation (the SediGraph® 5000ET, 5100, and 5120) over the next several years, Tony worked with sample cell and fluid handling design to improve repeatability and reproducibility of results. He participated in performance testing, final testing, and then test development, and he now assumes responsibility for all phases of the testing process.

During the development of the Saturn DigiSizer®, Tony became involved with its applications and sample dispersion, both in its later development stages and in assuming responsibility for training users in the field of laser particle size analysis.

With the development of the Elzone™ II 5390, Tony assumed responsibility for ensuring the compatibility of results with earlier versions of this instrumentation and the smooth conversion of its user interface to align with that of the entire Micromeritics line of instruments. Similarly, with the introduction of the Particle Insight instrument, Tony was responsible for evaluating its operation and reliability as an offering in the Particulate Systems line of products.

For many years, due to his background in chemistry and his intimate understanding of the Micromeritics product line, Tony has assumed the responsibility for technical training of both customers and Micromeritics personnel, covering all aspects of education from theory of operation to report generation.

In his current role as the Director of Product Integrity and Performance, as well as in his prior roles as Senior Product Scientist and Laboratory Manager, he has provided ongoing applications support to customers for particle size instrumentation as well as for other product lines, including the physisorption and chemisorption instrumentation and pycnometer instrumentation.

Jacek Jagiello - Senior Scientist

Dr. Jacek Jagiello received his M.S. degree in chemistry from Jagiellonian University, in Krakow, Poland, with a specialty in Quantum Chemistry. He received his Doctorate in Chemistry at M. Curie-Sklodowska University, Lublin, Poland in 1984, studying the thermodynamics of physical adsorption on heterogeneous surfaces, under the supervision of Prof. W. Rudzinski.

Dr. Jagiello has authored and co-authored more than 90 scientific publications, including two book chapters and more than 40 lectures presented at international conferences. He has also co-authored four U.S. patents.

In 2008, Dr. Jagiello joined Micromeritics, where he is involved in the development of methods for interpretation and modeling of adsorption measurements. His research interests are focused on adsorption properties of non-porous and porous materials – with special interest in the advancement of the understanding and characterization of activated carbons.

He began his study of the theory of physical adsorption on heterogeneous surfaces as an Assistant Professor and Research Assistant at the University of Science and Technology (AGH) in Krakow. As a Postdoctoral Research Associate at the Centre National de la Recherché Scientifique (CNRS) in Mulhouse, France, he studied Inverse Gas Chromatography, participating in a group under the direction of Dr. Papirer. Later, holding a second postdoctoral position with Prof. Schwarz at Syracuse University, Syracuse, New York, he worked on hydrogen and methane storage on activated carbons.

In 1996, Dr. Jagiello moved from academic to industrial research when he joined the Carbon Research Group at the Charleston Research Center of Westvaco Corporation in Charleston, South Carolina . His research projects were primarily related to the development of methods for characterization of activated carbons and to the pore structure-based modeling of carbon performance for specific applications. Later, collaborating with several international scientific groups, Dr. Jagiello contributed to research in the area of adsorption of various gases, including hydrogen, on carbon nanotubes, metal organic frameworks, and other porous materials, while he worked at Quantachrome, Boynton Beach, Florida. One year before joining Micromeritics he returned briefly to academia as a visiting scientist at The University of Kentucky Center for Applied Energy Research, where he conducted research projects in the areas of energy storage in carbon double layer capacitors and the capture of CO2 from the flue gas of coal fired power plants.

Simon Yunes - Senior 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.

Jack Saad - Associate Scientist

As an undergraduate, he worked with a variety of tungsten compounds to induce photo-initiated polymerization of cyanoacrylate using specific wavelengths of visible light, an application used in the adhesive industry.

Mr. Saad began his career at Micromeritics Instrument Corporation as a particle size analyst for their contract laboratory service where he developed protocols to obtain particle size distributions using light scattering, x-ray sedimentation, and electro-zone sensing techniques.

Beginning in 2004, Mr. Saad worked in the pharmaceutical industry at Kiel Laboratories and Elan Pharmaceuticals as a laboratory analyst for seven years for raw materials testing, manufacturing support, research and development, and quality control.

Mr. Saad rejoined Micromeritics in July 2011 as an Applications Specialist. In this position, he is responsible for applications support for particle size instrumentation and conducting research on potential applications for instruments and techniques.

Mr. Saad is also the Accreditation Coordinator for MLC. In this role, he organized the procedures and policies for Micromeritics instrument training program. He maintains the database of policies and procedures that govern the training program. His work prepared Micromeritics Learning Center for accreditation by the Accrediting Council for Continuing Education and Training (ACCET).

Mr. Saad is a member of the American Chemical Society (ACS) and American Association of Pharmaceutical Scientists (AAPS).

Chris Brown - Lab Analyst II

Christopher Brown graduated from the University of Georgia in with a B.S. in Biology.   He has been with Micromeritics since 1999 and specializes in Mercury Porosimetry.  Chris has run more varieties of samples for Mercury Porosimetry than anyone else in the world.

Pearl Kwon - Lab Analyst II

Pearl Kwon graduated from the University of Georgia with dual BS degrees in Chemistry and Biochemistry & Molecular Biology. She started working at Micromeritics in May 2017 as a Lab Analyst in charge of Gas Adsorption.

Jan Gifford - Lab AR

Jan Gifford graduated from Gwinnett Tech with an Associate degree in Business Management.
Jan has been working with Particle Testing Authority since 2017 in the Accounts Receivable Department.

Henry Forrest - Quality Assurance Associate

Henry Forrest recently joined the Particle Testing Authority team in March of 2018 as the Quality Assurance Associate.  A portion of his job duties is to conduct quality reviews of the analysis before the results reach the customer.  Prior to joining the team, Henry spent 5 years in the United States Marine Corps as a Military Policeman and 13 years as a Police Officer in the Metro Atlanta area.  His free time is spent with his son and daughter, listening to live music and finding new and interesting places to eat.

Jacob Goodman - Lab Analyst I

Jacob Goodman graduated from University of Georgia in December of 2018 with a B.S. in Environmental Health. He has been with Micromeritics since March 2019 and is currently the main analyst for the particle size section.

Ping Guo - Technology & Applications Consultant

Dr. Guo has been fascinated by nanomaterials since her college research experiences at Shandong University in China and National University of Singapore. After receiving her Bachelor of Science degree in chemistry with honors from Shandong University, she went to the University of Michigan in Ann Arbor to pursue a Ph.D. in chemistry. Advised by Prof. Adam Matzger and in collaboration with Prof. David Gidley, Dr. Guo studied water interaction with metal organic frameworks using positron annihilation lifetime spectroscopy (PALS). Dr. Guo’s work has been published in leading journals such as Journal of the American Chemical Society.

A passion in advanced analytical technologies brought her to a career in scientific instrumentation after her graduation. As a technology and applications consultant at Micromeritics, she uses her expertise in characterization of porous materials to help clients achieve success in research and development.

Israel Tordoya Henckell – Lab Analyst I

Israel Tordoya Henckell is a graduate from The University of Georgia, where he earned a dual Bachelors/Master’s degree in Pharmaceutical and Biomedical Sciences. He has a research background, writing his thesis on the role of leptin in obesity-associated breast cancer. He is excited to be a part of the Particle Testing team!

Hoang Nguyen – Lab Analyst II

Hoang graduated from the University of California, Irvine in 2011 with a B.S. in Chemical Engineering. Previously he worked as a Research and Development Engineer for Rosemount Analytical for several years and generated several patents. He joined Particle Testing Authority in March 2019 and is involved in several test areas.

Sanissa Xayamounkhoun – Lab Analyst I

Sanissa Xayamounkhoun graduated from the University of Florida (Go Gators!) with a BS degree in Microbiology and Cell Science. She started working at Micromeritics in January 2019 as a Lab Analyst in charge of Gas Adsorption.

Katharina Peikert – Scientific Services Europe

Dr. Katharina Peikert studied chemistry at the University of Hamburg. The area of materials science fascinated her already during her main studies. Her PhD under Prof. Michael Fröba has taken her into the world of porous materials, where she has focused on the synthesis and characterization of nanoporous metal-organic frameworks (MOFs) for the specific storage and release of nitric oxide.

In 2016, Dr. Peikert joined the German Micromeritics team and since then supports our customers with her experience in the characterization of porous materials.

Torben Sick – European Laboratory Manager

Dr. Sick has been managing the European laboratory in Germany since April 2018.

He has been studying porous solids since the beginning of his chemistry studies at the University of Hamburg. Working with zeolitic imidazolate frameworks (ZIFs) and hierarchically nanoporous carbon led him to a doctoral degree at the LMU in Munich focused on micro- and mesoporous covalent network compounds (COFs).