A5046253472- Power Transformer Diagnostics and Insulation
- High voltage insulation and dielectric phenomena
- Electrohydrodynamics and Fluid Dynamics
- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Electrochemical Analysis and Applications
- Air Quality Monitoring and Forecasting
- NMR spectroscopy and applications
- Electrostatic Discharge in Electronics
- Atmospheric and Environmental Gas Dynamics
- Lightning and Electromagnetic Phenomena
- Atmospheric Ozone and Climate
- Thermodynamic properties of mixtures
- Currency Recognition and Detection
- Laser-induced spectroscopy and plasma
- Power Quality and Harmonics
- Petroleum Processing and Analysis
- Spectroscopy and Quantum Chemical Studies
- Semiconductor materials and devices
- Carbon Nanotubes in Composites
- Coal Properties and Utilization
- Vehicle emissions and performance
- Plasma Diagnostics and Applications
- Hydrocarbon exploration and reservoir analysis
- Industrial and Mining Safety
Kentucky imaging Technologies (United States)
2023-2024
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2022-2024
Karlsruhe Institute of Technology
2020-2023
Rutgers, The State University of New Jersey
1987-2005
University of Strathclyde
2003
European University of Rome
2002
Keio University
2002
Sapienza University of Rome
1992
University at Buffalo, State University of New York
1986-1988
ExxonMobil (United States)
1976-1987
Abstract. Megacities and other major population centres (MPCs) worldwide are sources of air pollution, both locally as well downwind. The overall assessment prediction the impact MPC pollution on tropospheric chemistry challenging. present work provides an overview highlights a new contribution to understanding this issue based data analysis EMeRGe (Effect transport transformation pollutants Regional Global scales) international project. focuses atmospheric chemistry, dynamics, local...
A technique has been developed which allows the determination of specific conductance in bulk a liquid, independent electrode materials or separation. By this method, benzene saturated with air determined to be 1.1±0.1×10—14 Ω—1 cm—1 for fields between 50 and 400 V/cm. Measurements potential gradients electrodes show them strongly asymmetric. The temperature dependence dark current conduction shown follow typical relation normally associated semiconductance. value E 0.42±0.4 eV both liquid...
Agricultural greenhouse gas (GHG) release is the most dominant anthropogenic emission sector of methane (CH4) and nitrous oxide (N2O), therefore contribute significantly to global warming. However, there are large uncertainties in both, top-down bottom-up estimates especially on regional scale. Process models have difficulties properly reproduce complexity underlying GHG formation processes. In addition, complicated measurement conditions, such as areas, strong temporal variability spatial...
Abstract. This study introduces a helicopter-borne mass balance approach, utilizing the HELiPOD platform, to accurately quantify methane (CH₄) emissions from coal mining activities. Compared conventional research aircraft use of an external sling load configuration eliminates need for aeronautical certifications, facilitates easier modifications and enables local helicopter companies conduct flights. Furthermore, it allows plume probing as close several hundred meters downwind emission...
Sulfur dioxide (SO2) is an air pollutant that toxic to humans and, as a precursor sulfuric acid, has far-reaching consequences for the environment and climate. Anthropogenic emissions are responsible two-thirds of total SO2 into atmosphere. Stricter regulations technical developments, such installation desulfurization systems in coal-fired power plants, reducing parts world Europe. However, inventories show stagnation Middle East region recent years. In global catalogue provided by NASA,...
Global warming is proceeding rapidly and quick actions are required to suspend the increasing temperatures globally. Here we give an overview of a series measurement studies, supported funded by UNEP´s International Methane Emissions Observatory (IMEO) in 2022-2023. (CH4) primary focus all these since it one most potent greenhouse gases, which at same time has relative short lifetime. Due specific characteristics, CH4 presently prime target for mitigating emissions from industrial...
Flaring is the controlled burning of natural gas, a common practice in oil and gas (O&G) industry. Ideally, combustion process supposed to convert potent methane (CH4) completely into carbon dioxide (CO2), yet real-world situations this not case. According International Energy Agency (IEA), flaring responsible for about 10 % total emission O&G sector.  Therefore, it important understand quantify how efficiently flared fuel converted CO2, support mitigation emissions....
The phenomenon of electrical breakdown in condensed matter has been the subject many studies. While ultimate result is relatively easy to observe and study, attempts uncover its initial phases that lead short circuit as evidenced by light acoustical emissions defied discovery. In past decades some process have elucidated with help sophisticated devices permit registration on photographic film and/or transient digitizing instruments. progress made this field summarized an attempt establish...
The prebreakdown and breakdown processes have been recorded in n-hexane toluene Marcol 70, both a pure state with selected impurities. study was carried out using point-plane geometry. A low ionization potential additive had only small effect on the voltage or streamer propagation speed but did significantly alter shape of when needle positive, an anode. For negative needle, cathode, chemical impurities affected voltage. significance these findings is discussed detail.
The electrical breakdown process in highly purified and degassed liquid hydrocarbons has been studied, using high speed schlieren photography as well photomultipliers an optical multichannel analyzer. It was shown that the appears to be initiated primarily on cathode surface. ensuing formation of tree-like streamers found associated with light emission. This same spectral composition given off during actual breakdown. Spectral analysis emitted indicated presence atomic molecular hydrogen,...
The events occurring just prior, during, and after electrical break-down in liquid hydrocarbons have been photographed using 15 ns laser pulses produced with a ruby laser, to illuminate the space between two parallel plate electrodes, schlieren optics. In this manner it was possible obtain experimental evidence of density gradients by movement charge carriers during prebreakdown energy released breakdown. Bysplitting beam delaying one half 40 respect other, electrode gap could be studied as...
The phenomenon of electrical breakdown in insulating liquids has been investigated extensively for decades by many researchers all over the world. Several theories have advanced, based on more or less limited experimental evidence. Also attempts were made to apply concepts derived solids and gases. In last decade advent very high speed electrooptical tools it possible elucidate this process much detail than was previously possible. It become show that at least three stages are involved...
Abstract. The number of large urban agglomerations is steadily increasing worldwide. At a local scale, their emissions lead to air pollution, directly affecting people's health. On global an increase greenhouse gases, climate. In this context, in 2017 and 2018, the airborne campaign EMeRGe (Effect Megacities on transport transformation pollutants Regional Global scales) investigated European Asian major population centres (MPCs) improve understanding predictability pollution outflows. Here,...
It is noted that the past three decades have seen significant changes in types of materials used for electrical insulation. These were brought about by realization some previously detrimental to environment and people who came contact with them. The use polychlorinated biphenyls was prohibited, replacement had be developed. Paper replaced a large extent polymer film, paraffinic oils finally as derived from naphthene. At same time progress made understanding nature charges how they move...
Different dielectric fluids used in HV electrical components were subjected to AC stresses, and the partial discharge (PD) spectra produced under nonuniform uniform field conditions recorded with help of an detector a multichannel analyzer (MCA) as function applied stress. The analysis collected data confirms that PD activity liquid is random phenomenon well breakdown process. presence may be related bubbles near electrode interface low density region (vapor phase), which first step...
High-speed electrooptical techniques are used to study prebreakdown behavior in n-hexane and toluene at pressures between 0.1 5 MPa. The results show that pressure inhibits the formation of low-density regions increases inception voltage. observed effects suggest region is result liquid vaporization near electrode. Results obtained with a chopped voltage pulse indicate shape applied not critical streamer growth. Streamers were growing after had been removed, which suggests growth process is:...
High-speed schlieren studies have been carried out on the electrical breakdown of liquid hydrocarbons using a pulsed ruby laser. The development and propagation charge carrier trajectories were recorded photographically prebreakdown, breakdown, postbreakdown events occurring in very pure, oxygen-free samples hexane, benzene, toluene, isooctane parallel plate electrode geometry. initiation was characterized by growth narrow streamers creation which attributed to field injected electrons at...
The electric conductance of methyl-substituted benzenes has been determined between 20° and 65°C both in the presence absence oxygen over a range fields (50 to 1200 V/cm). Five six compounds studied resembled benzene their behavior. Although conduction level decreased with increasing number substituent methyl groups, thermal activation energy, within experimental error, was same similar that benzene. behavior 1,3,5-trimethylbenzene found differ all respects from other members this series....
The electric conductance of aliphatic and olefinic type hydrocarbons has been determined between 25° 65°C. both in the presence absence oxygen using fields 50 to 1200 V/cm. Based on observed potential distribution, thermal activation energies, conductivities, it was concluded that conduction processes two types compounds are distinctly different. appears be attributable very low concentrations polar impurities. Olefinic-type were found have higher conductivities as structurally similar...
At present, several definitions of partial discharge inception voltage (PDIV) have been advanced. To establish the value each these definitions, four practical electrical insulating fluids are selected, and their PDIV is determined according to three different specifications. The results suggest that use as a quality criterion generally not warranted. significance findings discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
The dielectric properties of six test fluids (MDBT, DTE, DINP, PXE, PFPE, and PPMS) were evaluated under AC DC stresses. data suggest that conduction is less sensitive to molecular structure effects than impurities while reflects more characteristics. Within a family such as liquid aliphatic hydrocarbons, both the breakdown level are adversely affected by which increase their conductivities. Among different types fluids, has significant impact on impulse breakdown. Conventional (50 or 60 Hz)...