Sam Barros – Project Manager / Research Engineer at Nostrum Energy
h5. How did you get into electronics/ engineering and when did you start?
I like to think I got started in electronics when I was 7 years old: I bent a hair pin so I could stick it in an electrical outlet, blackening the wall around it tripping the breaker. My experiments have obviously become a lot more sophisticated since then, but that basic sense of curiosity and passion for discovery that lead me to try something out to see what would happen remains to this day. As a child, and then later on a teenager, I participated in a lot of science fairs, and did fairly well, winning scholarships and travelling abroad to compete in larger events, and this helped consolidate in my mind the feeling that there were real worthwhile opportunities in a science career, so when I graduated high school, the decision to enroll in Engineering school was well cemented in my mind. I chose Engineering instead of a more broad, scientific degree, because to me it represents applied science, which is what I strive for; I’ve always enjoyed learning about a subject, and then using that knowledge in a practical manner to create or improve on something.
h5. What are your favorite hardware tools that you use?
Too many to list! On a daily basis, my Ti-nspire CX calculator (substituting my trusty old TI-89 that served me so well through years of Engineering school), a Fluke 115 True-RMS DMM (nice enough to give me data I can trust, but cheap enough that I don’t worry if something happens to it), and a Tecktronix four channel storage scope to help me make sense of complex systems where one signal can depend on two or more inputs. I’m not afraid to leave the laboratory and spend the day machining if a custom part needs to get done, so I am very glad to be experienced in using mills, lathes, welders and, to a smaller degree, some CNC machines we have available at the lab. Similarly, I’ve also had the pleasure to use some rapid prototyping technologies in my line of work, and am always impressed by how quickly we can go from design concept to fully functional prototype via that route.
h5. What are your favorite software tools that you use?
Microsoft Excel is probably number one. It allows me to sort through massive amounts of data and manipulate it in ways that make sense; performance trendlines, outliers, and averages all become obvious when sorted in the right way. I always try to sort all my data in Excel because I find that it makes it a lot easier to communicate the bottom line to upper management once I can identify what the fundamental trend is. The entire Microsoft Office suite suits my job well, and I use Word, Power Point, Access, etc daily. A second favorite would be Solid Works; I recently switched from ProEngineer (I like both, but work has chosen Solidworks as our current design platform, so I adapted), and I spend a lot of time refining models that represent what the final part will be like. I enjoy running FEA simulations on almost everything I design in SolidWorks, and believe that, while simulations like FEA are not the be-all-end-all to engineering design, they certainly help cut down on costly mistakes before a part is ever produced. In the electronics world we also have Micro Sim PSpice, which does with electronic circuits what FEA does for mechanical devices. Another software tool required on my job is GTPower, a very powerful engine simulation suite that I am still trying to become effective with.
h5. What is the hardest/trickiest bug you have ever fixed?
A few come to mind: In my previous job I worked for a company that specialized in High Voltage special effects; we used large Spark Gap driven Tesla Coils to produce real lightning bolts that could be up to several million volts, and incorporated these into shows, movies, etc… The high voltage sources could be real interference nightmares at times; broadband RF from the sparkgap, large ground currents, and a strong signal at the resonant frequency of the source. In one of my jobs we were at a large expo center in New York City for the unveiling of a major automaker’s new car; there were tens of millions of dollars of sound and lighting equipment around the car and the publicity company wanted the car to be hit by a lightning bolt as it drove towards the audience. We assembled a Tesla Coil upside down on the ceiling and ran a transmission line over to where the car would be. When the power was switched on, we then found that all the intelligent lighting around it would stop working, the speakers popped and crackled, and a large screen on the back of the display would crash and had to be rebooted. We were at a loss trying to figure out what was causing the interference; some of the team believed it was coming back through the power lines, others thought it was caused by poor grounding. I isolated the problem by taking one single intelligent light, mounting it on a chair across the room, and gradually bringing it closer to the coil; it worked far away and stopped working at a certain distance, which confirmed my suspicion that the interference was neither caused by ground currents or by inductive kickback into the power lines. The cables on all those lights are shielded, and my conclusion is that the shield was coupling RF power that was being broadcast by the coil and then forming a ground loop between the light and its controller. Lifting the ground at the controller solved that problem completely. The screen was too close and coupled too much power, so we put a grounded faraday cage in front of it, and interference on the speakers was solved via RF attenuating chokes that consisted of ferrite cores with a few turns of wire wrapped around them. All this was done in just two days since the unveiling could not be moved back!
In my electronics hobby I like to work with large high voltage power supplies, particularly capacitor banks that I use for electromagnetic acceleration projects (RailGuns, CoilGuns, etc). The basic principle is simple; a power source stores energy over a long period of time in a capacitor bank, and the bank then releases it almost instantaneously. That way a 3Kilowatt power supply can charge 300 thousand joules worth of energy in about a minute and a half, and then the energy storage medium can release that energy back at a rate of several million, or even a billion plus watts for a few uS. The results are always spectacular; magnetic fields bend and buckle inch wide bussbars, and small metal objects can be moved at supersonic speeds by virtue of the electromotive forces alone. Conversely though, managing those pulses poses very difficult challenges for which there is not a lot of published literature; measuring those currents is particularly difficult; if not for the challenge in finding a current shunt or Ragowski coil that can handle them, but also for the fact that a very strong EMP is generated during the pulse (enough to make overhead fluorescent lamps flash momentarily). Without good data on what is happening, optimization becomes very difficult. Identifying stray inductances and finding where the source of oscillations in the circuit requires as much imagination as it does hard scientific knowledge, and designing components to survive the resulting forces is an ongoing challenge. Making a railgun survive a 180kilojoule shot that saw peak currents reaching over 3.5million amperes was a particularly challenging endeavour that cost equal amounts in both hardware and test equipment.
On my day job, a lot of my work revolves around implementing and operating computer engine management on prototype engines that were originally designed for mechanical controls. In those engines, the challenge is instrumenting the engine is such a way as to provide the engine control unit (ECU) with all the information it needs about engine operation (speed, airflow, air/fuel ratio, etc), and then creating a set of tables that allow it to make the correct decisions regarding fuel delivery and injection timing. Challenges here stem from situations where a change in operating parameters causes the engine operating condition to deviate from ideal, but attempts by the ECU to correct that cause the system to oscillate as it “chases its own tail”, so to speak; each subsequent change causes the operating condition to deviate further from ideal. At some point you have to start making compromises and trading efficiency for stability.
If there is one thing I have learned from troubleshooting different systems is that it is very easy to focus on the problem you see, and lose track of the fact that many times (most times?) what is being observed is a symptom of something else more fundamental that is happening upstream. The good engineer must always be able to differentiate between root causes and symptoms and systematically follow a problem upstream to find what originates it.
h5. What is on your bookshelf?
Thousands and thousands of pages printed out of IEEE transactions on magnetic and SAE conference proceedings, and mostly reference books; anything from “TI-Nspire for dummies” and “Microsoft Expression Web in 24 hours”. To Haywood’s “Internal Combustion Engine Fundamentals”, “The Merck Index”, CRC Encyclopedia of Science and Technology”, “Machinery Handbook”, “Mechanism Design”, etc… I only buy books I know I’ll come back to time and time again when I need hard facts, figures, or a good reference on how to do something right; for anything else, there is the library.
h5. Do you have any tricks up your sleeve?
I write down notes at the end of the day concerning what was done at work and what is pending, and I sort all my project results in Microsoft Excel, but I think these are tricks any good Engineer has…
h5. What has been your favorite project?
Hands down working on my Railgun, since it is a hobby project and therefore something I do when I feel like it and however I want to; having the freedom to come up with my own designs and not have to answer to upper management is great. A close second would be a job I did in Hong Kong back in my High Voltage Special Effects days; I designed a stunt where a performer wore a chainmill suit and walked atop an insulated platform during his show (a 15 day tour that sold out the very day tickets became available!); 3 other performers, also wearing chainmill surrounded the platform, and a very large Tesla Coil was lowered from the ceiling, causing 20 foot long lightning bolts to come down on the singer, who would then point his hands to each of the performers and send out a second spark to them, equal in length to the distance between his feet and the bottom of the platform. It was one of the most difficult projects I’ve ever been involved in, it was extremely stressful to install and work out all the kinks, I was working with only one other technician and we had such a short deadline that I ended up working back to back 18+ hour days for almost a week, but when it all came together it was absolutely spectacular and the crowd was thrilled. Personal satisfaction is an important part of a job well done and this one really delivered in that aspect. You can see a short clip of the stunt on Youtube.
h5. Do you have any note-worthy engineering experiences?
I once discharged a 10,000 volt, 10Kilojoule pulse capacitor through a watermelon just to see what would happen. The capacitor was a 150 pound metal can left over from a government laser research project and could literally dump millions of amperes into the watermelon. It sounded like a bomb going off and literally painted the walls of my garage with chunks. Cleaning that up was no fun, but it was one of the most vivid demonstrations of electrical power I have ever seen. Here’s a picture.
h5. What are you currently working on?
A million different things! For my job I am currently developing two different power generating units; one a multi fuel unit designed to burn Diesel/Biodiesel/JP-8, and the other one a spark ignited natural gas generator; both involve a couple of sub-projects in air charge temperature management and fuel atomization. As a hobby, I am putting together a 10-Stage full wave Cockroft-Walton voltage multiplier that I am hoping will take in 40kV and step it up to 400kV DC; I plan on using that high voltage source for some experiments with electrostatic propulsion. I’m still working on my Railgun research as well, and I would like to build my first large MARX generator by the end of the year; I’ve got all the capacitors and am trying to come up with a compact design that will output a one million volt DC spark.
h5. Can you sum up Nostrum Energy in one sentence?
Nostrum Energy is a startup company out of New Jersey that researches alternative fuels and high efficiency power generators.
h5. What are the main goals for Norstrum Energy and how do you accomplish these goals?
The main goal for my job is to increase the fuel efficiency of our research engines. There are several ways I accomplish this, but unfortunately I can not discuss them since we are still filing patents…
h5. What are some exciting things we can expect to see from Nostrum Energy in the near future?
I expect that we will be unveiling a line of very high efficiency power generators in the near future which will set the standard for fuel efficiency and reliability in their market segment.
