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We utilized tunable superomniphobic surfaces with flower-like TiO2 nanostructures to fabricate a simple device with precisely tailored surface energy domains that, for the first time, can sort droplets by surface tension. We envision that our methodology for droplet sorting will enable inexpensive and energy-efficient analytical devices for personalized point-of-care diagnostic platforms, lab-on-a-chip systems, biochemical assays and biosensors.

A differential sputter yield measurement technique is described, which consists of a quartz crystal monitor that is swept at constant radial distance from a small target region where a high current density xenon ion beam is aimed. This apparatus has been used to characterize the sputtering behavior of various forms of carbon including polycrystalline graphite, pyrolytic graphite, and PVD-infiltrated and pyrolized carboncarbon composites. Sputter yield data are presented for pyrolytic graphite and carbon-carbon composite over a range of xenon ion energies from 200 eV to 1 keV and angles of incidence from Oo (normal incidence) to 60°.

Molybdenum oxide (MoOx) and molybdenum oxynitride (MoON) thin film back contacts were formed by a unique ion-beam sputtering and ion-beam-assisted deposition process onto CdTe solar cells and compared to back contacts made using carbon–nickel (C/Ni) paint. Glancing-incidence x-ray diffraction and x-ray photoelectron spectroscopy measurements show that partially crystalline MoOx films are created with a mixture of Mo, MoO2, and MoO3 components. Lower crystallinity content is observed in the MoON films, with an additional component of molybdenum nitride present. Three different film thicknesses of MoOx and MoON were investigated that were capped in situ in Ni. Small area devices were delineated and characterized using current–voltage (J-V), capacitance–frequency, capacitance–voltage, electroluminescence, and light beam-induced current techniques. In addition, J-V data measured as a function of temperature (JVT) were used to estimate back barrier heights for each thickness of MoOx and MoON and for the C/Ni paint. Characterization prior to stressing indicated the devices were similar in performance. Characterization after stress testing indicated little change to cells with 120 and 180-nm thick MoOx and MoON films. However, moderate-to-large cell degradation was observed for 60-nm thick MoOx and MoON films and for C/Ni painted back contacts.

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Firefighting personnel have long suffered physiological strain as a result of exposure to strenuous activity and harmful environments. Some of the strain is due to heat induced from lengthy exposure to high temperature environments and when performing strenuous work during long fire suppression activities. The results of these work conditions can lead to high internal body (core) temperature and cardiac events from overexertion, which has been identified as the leading cause to firefighter deaths. Thermoelectric refrigeration has been shown to have applications for portable cooling of firefighting personnel, having higher heat removal rates when compared to vapor compression refrigeration systems. This project focused on system design and analysis of a thermoelectric cooling (TEC) module using bulk thermoelectric materials. Specifically, a TEC system has been integrated into a closed-loop water circulation system. The closed loop system continuously cools the circulating water, which is used to absorb heat from a heat source represented by either simulated or actual volunteer fire fighting personnel. The cooling rate was characterized as a function of both water flow rate and TEC power input. To simulate operation of the TEC module in elevated temperature environments, tests were conducted in an environmental chamber under varying water flow rates and TEC input power. In addition, core temperatures were measured for each firefighter test subject. Corresponding heat removal rates and coefficients of performance are provided for each test. A heat removal rate of 160 W was achieved during firefighter cooling, while more than 250 W of heat was removed during environmental chamber tests. Maximum COP values of 0.6 and 1 were obtained from firefighter and environmental chamber experiments, respectively.

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