This paper reports an integrated micro gas chromatography (μGC) architecture which utilizes a bi-directional micropump. Four integral components—the bi-directional Knudsen pump (KP2), a two-stage preconcentrator-focuser (PCF2), a separation column, and a gas detector—are integrated in a 4.3 cm3 stack, forming a serial flow path. All four components are fabricated using the same three-mask proce...

Pattern generation of well-controlled block copolymers (BCPs) with a high Flory-Huggins interaction parameter (χ) is important for applications in sub-20 nm nanolithography. We used mixed solvents of dimethylformamide (DMF) and toluene to control the morphology as well as the time to achieve the targeted morphology via self-assembly of BCPs. By precisely controlling the volume ratio of DMF and ...

Recently, a new type of bioreactor for air pollution control referred to as the foamed emulsion bioreactor (FEBR) has been developed. The process relies on the emulsion of an organic phase with a suspension of an actively growing culture of pollutant-degrading microorganisms, made into a foam with the air undergoing treatment. In the current paper, a diffusion and reaction model of the FEBR is ...

A lab-scale biofilter packed with mixed packing materials was used for degradation of toluene. Different empty bed residence times, 148.3, 74.2 and 49.4 s, were tested for inlet concentration ranging from 0.2 to 1.2 g/m(3). The maximum elimination capacity of 36.0 g/(m(3) h) occurred at an inlet loading rate of 45.9 g/(m(3) h). The contribution of the lower layer was higher than other layers an...

Clay-supported TiO2 photocatalysts can potentially improve the performance of air treatment technologies via enhanced adsorption and reactivity of target volatile organic compounds (VOCs). In this study, a benchtop photocatalytic flow reactor was used to evaluate the efficiency of hectorite-TiO2 and kaolinite-TiO2, two novel composite materials synthesized in our laboratory. Toluene, a model hy...

We describe herein the construction of simple, low-power, broadly responsive vapor sensors. Insulating polymer-conductor composites have been shown to swell reversibly upon exposure to vapors. Thin films of polymer composites have been deposited across two metallic leads, with swelling-induced resistance changes of the films signaling the presence of vapors. To identify and classify vapors, arr...

Teflon chambers are ubiquitous in studies of atmospheric chemistry. Secondary organic aerosol (SOA) formation can be underestimated, owing to deposition of SOAforming vapors to the chamber wall. We present here an experimental protocol and a model framework to constrain the vapor–wall interactions in Teflon chambers. We measured the wall deposition rates of 25 oxidized organic compounds generat...