This paper describes simple modifications to thermally diffusive laminar flow ultrafine condensation particle counters (UCPCs) that allow detection of ∼1 nm condensation nuclei with much higher efficiencies than have been previously reported. These nondestructive modifications were applied to a commercial butanolbased UCPC (TSI 3025A) and to a diethylene glycol-based UCPC (UMN DEG-UCPC). Size a...

Overexposure to welding fume constituents, particularly manganese, is of concern in the construction industry due to the prevalence of welding and the scarcity of engineering controls. The control effectiveness of a commercially available portable local exhaust ventilation (LEV) unit was assessed. It consisted of a portable vacuum and a small bell-shaped hood connected by a flexible 2 inch (50....

BACKGROUND Camellia sinensis is the source of tea leaves and it is an economic crop now grown around the World. Tea seed oil has been used for cooking in China and other Asian countries for more than a thousand years. Tea is the most widely consumed beverages after water in the world. It is mainly produced in Asia, central Africa, and exported throughout the World. Some engineering properties (...

A previous study used a PortaCount Plus to measure the ratio of particle concentrations outside (C out) to inside (C in) of filtering facepiece respirators (FFRs) worn by test subjects and calculated the total inward leakage (TIL) (C in/C out) to evaluate the reproducibility of the TIL test method between two different National Institute for Occupational Safety and Health laboratories (Laborato...

Abstract. Secondary organic aerosol (SOA), formed through oxidation of volatile compounds (VOCs), displays complex viscosity and phase behaviors influenced by temperature, relative humidity (RH), chemical composition. Here, the efficacy a multi-stage electrical low-pressure impactor (ELPI) for indirect water uptake measurements was studied ammonium sulfate (AS) aerosol, sucrose ?-pinene-derived...

Compact low-cost sensors for measuring particulate matter (PM) concentrations are receiving significant attention as they can be used in larger numbers and in a distributed manner. Most low-cost particle sensors work on optical scattering measurements from the aerosol. To ensure accurate and reliable determination of PM mass concentrations, a relationship of the scattering signal to mass concen...

Downward and upward ultrafiltration (UF) was performed using the suspensions of nanosized colloidal silica with different particle diameters and their filtration rates were compared. In downward UF, the filtration rate decreases as the particle diameter decreases because the specific filtration resistance of the filter cake becomes significantly higher. In contrast, the filtration rate in upwar...

Geometric constraints impact the formation of a broad range of spatial networks, from amino acid chains folding to proteins structures to rearranging particle aggregates. How the network of interactions dynamically self-organizes in such systems is far from fully understood. Here, we analyze a class of spatial network formation processes by introducing a mapping from geometric to graph-theoreti...

The use of pollen shape (spiked sphere) particles for dry powder inhalation is studied. Pollen shape hydroxyapatite (HA) particles are synthesized to cover both size ranges of typical drug and carrier particles for pulmonary drug delivery. The HA particles produced have geometric diameter range from 5-50 μm and effective density range from 0.2-0.72 g/cm. The flow properties of the powders are c...