5 Minutes with...Hamed Ghaednia

5 Minutes with...

Hamed Ghaednia, PhD Student, Mechanical Engineering at Auburn University

Hamed with his poster at the 2013 STLE Annual Meeting

What got you interested in tribology, and where has that interest led you? Looking back, I can recognize a couple of events over the course of my studies that prepared me and got me interested in the field of tribology.  While I was working on my undergrad I was offered to enter a double major program as part of an honors program.  I was given the choice to select a second major and I chose to study chemical engineering because of my fascination with chemical processes.  I did not know it at the time, but the mechanical/chemical engineering combination gave me a boost through my career in the field of tribology. My first exposure to tribology research was when I started working on my master’s degree.  I was looking for research topics that included both of my majors so I started working on the semi-active control of a rotor mounted on magneto-rheological journal bearings.  My research involved: numerical simulations of a rotors’ vibrations, MR fluid journal bearing modeling and design of a fuzzy control system.  My Master’s thesis was partly related to tribology. However, I had the opportunity to engage in a variety of research topics related to tribology when I began my PhD research at Auburn University.  That was when I began to really appreciate the complexity and interdisciplinary approach to tribology in solving unique and cutting edge problems, which got me interested in tribology. I have been active in the field of tribology ever since as a Research Assistant in the Multiscale Tribology Laboratory at the Auburn University and I have been involved in a range of topics such as nanotribology, lubrication and contact mechanics.

Can you give us some detail on your research? Currently, I am focused on the effect of nanoparticle additives on lubricants as my PhD project. Nano-sizes particles are small enough to infiltrate the small gaps between surfaces in contact and alter the tribological characteristics. However the particles’ exact enhancing mechanisms remain unknown (with a few exceptions). This project has different angles and challenges to be explored, such as stability of nanoparticle suspensions. Usually the base oils are non-polar so there is no strong intermolecular force available to suspend the particles. Nanoparticles change the bulk properties of the lubricants, such as viscosity and thermal conductivity, which need to be quantified. The main goal of the project is to understand the effect of particles on friction and wear and to study the interaction of particles with surfaces under high pressure.  This project involves a variety of different experimental techniques ranging from purely chemical tests to friction and surface analysis tests. In addition, I am working on developing a contact model for nanoparticles between rough surfaces. Therefore it is a very good opportunity for me to get involved in various tribological topics and try to increase my knowledge of tribology. I am two and half years into this project and have tackled multiple fronts of the project. Results so far are very interesting and I have couple of papers in publication and in preparation on the subject.

During my Master’s program I was working on magnetorheological (MR) journal bearings. MR bearings consist of a conventional bearings filled with the MR fluid.  MR fluid is a suspension of micron size ferromagnetic particles in a base oil. MR fluids’ viscosity and rheology changes under an applied external magnetic field that could be utilized to control the response of the bearing in a feedback control system.  The first goal of the study was to develop a heat transfer model for the bearings and explore the effect of temperature rise on the performance of the rotor-bearing system. The second goal was to design and implement a semi-active fuzzy control system to minimize the vibrations of the system.

What recommendations would you give to other students and researchers in the field? Grad school is usually stressful, lengthy and typically revolves around your research. Therefore take plenty of time to explore your possibilities and choose the research topic that you like and enjoy learning about. This can significantly improve your grad school experience.

As known, tribology mainly explores the contacts between different materials. These can be in different phases and are governed by different physical or chemical principles. Tribology links different physical and chemical concepts together in search of an answer.  Tribology does not stop at the edge of the materials; it bridges the gaps. Hence, if you are want to be involved in this field, my advice is to be willing to bridge the gaps and learn every day.

Any final thoughts you’d like to give readers? Don’t forget that many breakthroughs in the history of mankind came from early tribologists.  Examples of these are cavemen making fire out of friction and the invention of the first rolling element bearing, the wheel. Thus, it is probable that a tribologist will invent the next revolutionary device or discover the key to the next chapter of engineering!

For more info, click here to read The 10 Greatest Events in Tribology History (article and poster)

Hamed’s Favorites 
Tribology book/reference: Even though I use several tribology-related books on a regular basis, I can name three books as my favorites:

• Contact Mechanics by K.L. Johnson
• Intermolecular & Surface Forces by J. Israelachvili
• Fundamentals of Fluid Film Lubrication by Hamrock, Schmid and Jacobson | Read the review

Favorite professor(s)/mentor(s): Dr. Jackson and Dr. Ohadi, my PhD and Master’s advisors, are my favorite professors and mentors.
Favorite online resource related to your research: http://www.tribology-abc.com/
Favorite quote:  “Believe those who are seeking the truth. Doubt those who find it.” – Andre Gide, French critic, essayist, & novelist (1869 - 1951)

Biography
Hamed Ghaednia received his BS degrees in Mechanical Engineering and in Chemical Engineering from the Tehran Polytechnic (also known as Amirkabir University of Technology), Iran, in 2007 and 2010, respectively. During his undergraduate he was a member of the Parsian Robotic Group and participated in several international robotic competitions and won awards. He received his MS degree in Mechanical Engineering from Tehran Polytechnic in 2010 while working as a Graduate Assistant for the Vibration and Noise Control Laboratory. He is currently pursuing his PhD in Mechanical Engineering, in the field of Tribology, at Auburn University. He is currently a Research Assistant at the Multiscale Tribology Laboratory. He has published papers in the fields of: nano particle lubricants, magneto-rheological fluid (MR fluid) bearings and contact mechanics. His current research involvements are nanoparticle lubricants, nanotribology and contact mechanics.

Mr. Ghaednia is a member of the Society of Tribologists and Lubrication Engineers (STLE) and American Society of Mechanical Engineers (ASME).

5 Minutes With...Juliane Benedet, MechEng PhD Student, Imperial College London

5 Minutes with… 

Juliane, STLE Annual Meeting 2010, Las Vegas

Juliane Benedet, PhD student, Mechanical Engineering at Imperial College London

What got you interested in tribology, and where has that interest led you? To support myself through my undergraduate degree in Chemical Engineering I worked for the National Service for Industrial Training in Brazil, which is a network of nonprofit professional schools and technology centres that have been established and maintained by the Brazilian Confederation of Industry. These institutions provide formal training for specialized workers in the areas of chemistry, mechanics, construction, etc. Having always been interested in research, I found myself surrounded by like minded people who had a strong academic background. They encouraged me to specialise and pursue postgraduate qualifications.

Upon moving to the UK in 2006, I had the opportunity to work on the research and development of additives for both fuels and lubricants and when the opportunity to do a PhD in Tribology presented itself in the end of 2007, I did not think twice. When I first started I was looking forward to learning more about lubrication and lubricants, but given the multidisciplinary nature of this amazing science I have learnt so much more. It has been a great privilege to work alongside chemists, physicists, material scientists, chemical engineers and mechanical engineers in the Tribology group at Imperial College London, which has an outstanding reputation for experimental tribological research.

Can you give us some detail on your current research? Because energy demands are expected to double by 2050, lubricants are required to reduce friction and thus energy consumption, while maintaining reliability; throughout my PhD I have investigated the film-forming, friction and wear-reducing properties of a very wide range of potential, low and zero sulphated ash, phosphorus and sulphur (SAPS) antiwear additives of different chemical types to replace ZDDP in engine oils and mitigate its deleterious effects, i.e. (i) degradation of exhaust aftertreatment systems, (ii) increase in engine friction, which compromise fuel economy and (iii) corrosive-abrasive wear with soot in diesel engines.

I employed a multi-technique approach, i.e. MTM-SLIM, MTM-Reciprocating, AFM, FIB-SIMS, FIB-TEM, ToF-SIMS and XANES, in order to determine which classes of lubricant additive types are able to form protective boundary films that reduce wear and friction in rubbing contacts. This study benefits designers of the next generation of engine lubricants and also helps us understand at a more fundamental level the various ways that lubricants can control wear in boundary lubrication conditions.

What recommendations would you give to other students and researchers in the field? Although very rewarding, research can also be quite lonesome sometimes, so try to have perseverance, keep a close eye on the details and ask for help or a second opinion.

Tribologists and tribologists-to-be: don’t mind if most people have no idea what Tribology is. There are endless examples of “tribology-at-work” from cars and machines to joint replacements, food and hair products. No matter how much you try to explain, some people will still look puzzled and either say you are brainy or make a few lubrication-related jokes, don’t worry you can always count on your fellow tribologists.

What are some of your favorites?
Tribology/Mechanical Engineering book: Engineering Tribology by Gwidon Stachowiak and Andrew Batchelor
Professor: Professor Hugh Spikes, for his invaluable support, insights and encouragement throughout my PhD.
Website: Tribology ABC http://www.tribology-abc.com/
Interests: Because I am of Italian-Brazilian descent I have inherited a passion for food and cooking so I spend my free time trying new recipes and entertaining my good friends and family.

Biography
Juliane has received her Bachelor degree in Chemical Engineering in 2005, from the University of Southern Santa Catarina in Brazil, where she worked for the National Service for Industrial Training (SENAI, 1998-2005) in the investigation, optimization and knowledge transfer of rheological aspects of ceramic suspensions.

She began working in the R&D of additives in 2006 at Infineum UK, where she investigated lubricity and detergency improvers for diesel fuels, afterwards joining Castrol Ltd in 2007 to investigate the thermal stability of lubricating oils. She briefly re-joined Infineum in 2011 as a Power Transmission Fluid Technologist, responsible for proposing technical solutions to fluid related hardware issues.

Currently, she is a PhD student in the Tribology Group of the Mechanical Engineering Department at Imperial College London, where she has investigated the film-forming, friction and wear-reducing properties of a very wide range of alternative low and zero sulphated ash, phosphorus and sulphur (SAPS) antiwear additives of different chemical types to improve the next generation of engine oils and extend the life of vehicle exhaust aftertreatment systems.

5 Minutes with... Brendan Hanrahan, PhD Candidate, Materials Science and Engineering at the University of Maryland

Brendan Hanrahan

Biography

Brendan is currently working in the Energy and Power Division at the U.S. Army Research Laboratory while finishing his Ph.D. degree at the University of Maryland in Materials Science and Engineering. His research is focused on novel materials and fabrication methods for small-scale, portable power systems. The tribology of micro-scale ball bearing systems, designed to support micro-turbines, -pumps, and -generators, is the main focus of his research. Upon graduation in December, Brendan plans on seeking out an engineering position in industry.

Sniegowski: What got you interested in tribology?
Hanrahan: I started as a graduate student in Materials Science and Engineering at the University of Maryland in 2006. I joined the MEMS Sensors and Actuators Laboratory that Fall and my first project was to create a retainer ring (a restraining system for the balls that goes inside the device) for micro-scale ball bearing devices. The senior students in the group were developing micro-turbines, micro-pumps, and micro-motors at the time. While all of these devices were functional, they were all also limited by the micro-scale ball bearings, which were not really well understood. We got together and determined that one of us would need to focus on understanding the tribology of the microball bearings to improve the platform for all future devices. Being a Materials Scientist in a group of device engineers, the fundamental study fell into my lap. From that point, I designed experiments help us better understand the sources of friction, the different wear regimes, and the applicability of lubrication for micro-scale ball bearings.

Sniegowski: What are you currently working on?
Hanrahan: My current research at the U.S. Army Research Lab is focused on micro-scale ball bearing systems, designed to support power and energy applications, including small generators, fuel pumps, sensor platforms, and an array of other applications. The biggest part of this research has been focused pinpointing the sources of rolling friction when you utilize micro-scale geometries, silicon materials systems, and microfabrication technologies. My Ph.D. hypothesis is centered around the influence of adhesion on rolling friction. To address adhesion I have designed experiments that independently address various aspects of adhesion, such as real contact area and adhesive energy. These results, plus continued studies on wear regimes and new microfabrication geometries, will provide a reference point for the engineering of future microfabricated ball bearing systems.

Sniegowski: What recommendations would you give to other students in the field?
Hanrahan: First, teach your parents, colleagues, and teachers what “tribology” means! Second, you may find yourself at the business end of a number of lubrication (lube), friction, or ball-related jokes. Don’t be fazed! Just ask them if they appreciate the fact their car stops, windmills turn, or their engines last a long time. Third, I would guess that with few exceptions, most undergraduates haven’t been introduced to tribology as field of study, so most graduate students don’t seek out tribology, but rather tribology finds them. This comes in the form of a part wearing out, a slow motor, or some other issue that needs solving. My advice to them is to dive-deep into some of the older, seminal works of tribology. You will find that every problem in tribology is specific to the geometry, materials, and operating parameters of your system. It’s best to go back and learn the general formulas, test methods, and models which are universally true before looking into something more specific.

Some of the papers Brendan recommends:

• "Surface Energy and Contact of Elastic Solids" - Johnson, Kendall, Roberts, 1971
• "The Mechanism of Rolling Friction 1: The Plastic Range" - Eldredge and Tabor, 1955
• "The Mechanism of Rolling Friction 2: The Elastic Range" - Tabor, 1955
• "Elastic Deformation and the Laws of Friction" - Archard, 1957

If you'd like to be interviewed for our 5 Minutes highlight, just send me (Kara) an email at klemar@stle.org.