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 Urban forest soil is often disturbed by rapid urbanization. Organic mulching effective for improving quality and aggregate stability. This study evaluated how binding agents changed stability through organic in urban soils. Three treatments were applied Jiufeng National Forest Park, Beijing: (1) no mulch (control); (2) wood chips alone (5 cm thickness); and, (3) + compost (This was div...

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...

this study determined some spectral characteristics and relationship between landsat spectral reflectance and soil surface color in the arid region of iran (kashan). the study carried out in the kashan area that covers 90000 ha. consisting of mountain, hills and flood plain. enhanced thematic mapper (etm+) data collected on july 2002 were used for this research. the color composite images produ...

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...

The main goal of this study was to improve the knowledge of ultrafine particle number distributions in large urban areas and also to call the attention to the importance of these particles on assessing health risks. Measurements of aerosol size distributions were performed during 2 weeks, with distinct pollutant concentrations (polluted and clean periods), on the rooftop of a building located i...

Soil emissivity signatures were constructed using the digital imaging and remote sensing image generation (DIRSIG) model and Blender three-dimensional (3-D) graphic design software. Using these tools, the geometry, radiometry, and chemistry of quartz were exploited to model the presence of particle size effects in the thermal spectra of disturbed soil. Using the physics engines within the Blend...

In order to effectively control vibration related problems, the development of a reliable vibration monitoring system and the proper assessment of attenuation characteristics of various vibrations are essential. Various ground vibrations caused by train loading, blasting, friction pile driving and hydraulic hammer compaction were measured using 3D geophones inside of the borehole as well as on ...