Dr. Bruno has been a leader in the area of fuel characterization throughout his 30 years at NIST. He initially worked on gaseous mixtures of hydrogen and hydrocarbons and natural gas constituents, developing a direct measurement of hydrogen fugacity. He and his colleagues developed approaches to study the thermophysical properties of chemically reacting fluids (primarily fuel related), an activity that has continued to the present, with decomposition kinetics measurements on modern fuels. Interestingly, this work resulted in the development of one of the world's longest Arrhenius plots (spanning 11 orders of magnitude) for the thermal decomposition of the rocket propellant, RP-1. Most recently, he introduced the advanced distillation curve (ADC) approach for the characterization of complex fluids (primarily fuels). This method links thermodynamically consistent boiling temperatures to fluid composition, thus providing a theoretically meaningful basis on which to model fuel volatility. The method is used in numerous labs worldwide, and the essential components have been commercialized. To view a brief movie about this method, visit: http://www.nist.gov/public_affairs/techbeat/tb2008_0610.htm#crude).
Trace Constituent Analysis:
The importance of trace constituents on the overall properties of complex fluids (such as fuels, bioproducts, etc.) is well understood. The contamination the natural gas pipelines with traces of polychlorinated biphenyls (PCBs) was recognized two decades ago, and the effect of PCBs on mixture properties were critical to design separation methods. Dr. Bruno and his colleagues developed the first concatenated approach to vapor pressure measurement, to rapidly characterize the 209 PCB congeners. This has lead to the 18-station instruments that we use today. Related to PCB analyses are our developments of surface energetics measurements. Beginning with the PCBs, we have developed metrology to measure interaction energies of trace fluids on surfaces. Our Group's extensive work with alternative refrigerants required the development of many trace constituent analytical procedures, standard data and databases. This work played an important role in the effective development of many of the thermodynamic and transport property models that have been released. In the area of bioproducts separation, Dr. Bruno and his colleagues made extensive use of supercritical fluid and alternative solvents (including alternative refrigerants) for extraction, resulting in many measurement methods and model development. He introduced Sepsol (separator/solvator) to simplify extraction and solute stabilization.
The chemical analysis of condensed phase constituents can often be simplified by measuring them in the vapor space above their bulk, a concept called headspace analysis. The method has come a long way since the earliest purge and trap methods were introduced. Dr. Bruno recently introduced a new approach to headspace sampling: PLOT cryoadsorption. This method uses a porous layer of sorbent in a capillary column as the trap. He and his colleagues have shown that quantitative measurements can be obtained (with an uncertainty of 10 %) from a matrix with 10 ppb of the target solute, and a qualitative measurement with only 2 ppb. They have applied the method to energetic materials, food spoilage and the location of illegally buried corpses.
Areas of Research / Professional Expertise
Properties of liquid and gaseous fuels