17 research outputs found
Fabrication and Performance of a Multidischarge Cold-Atmospheric Pressure Plasma Array
Cold atmospheric-pressure plasma (CAP) has been shown to kill bacteria and remove biofilms. Here, we report the development of a unique CAP array device consisting of a parallel stack of eight linear-discharge plasma elements that create a ∼5-cm2 (2.4 cm × 2 cm) treatment area. The CAP device is fabricated from low-temperature cofired ceramic (LTCC) layers to create 24-mm-long linear-discharge channels (500-μm gap) with embedded opposing silver metal electrodes. A 20-kHz ac voltage (0.5–5 kV) applied to the electrodes generates an Ar/O2 plasma a between the plates, with the gas flow directing the reactive species toward the biological sample (biofilms and so on) to affect the antimicrobial treatment. External ballast resistors were used to study discharge uniformity in the stacked array elements, and internal thick film ballast resistors (≈150 kΩ) were developed to create a fully integrated device. Typical element discharge currents were 1–2.5 mA with the total array current tested at 20 mA to provide optimal device uniformity. The plasma discharge was further shown to produce reactive hydrogen peroxide and exert antimicrobial effects on Pseudomonas biofilms and Salmonella contaminated eggshell samples, with \u3e99% of the bacterial cells killed with less than 60 s of plasma exposure
Recommended from our members
Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures
The level of agreement between climate model simulations and observed surface temperature change is a topic of scientific and policy concern. While the Earth system continues to accumulate energy due to anthropogenic and other radiative forcings, estimates of recent surface temperature evolution fall at the lower end of climate model projections. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. Applying the methodology of the HadCRUT4 record to climate model temperature fields accounts for 38% of the discrepancy in trend between models and observations over the period 1975–2014