Effect of Particle Shape and Charge on Bulk Rheology of Nanoparticle Suspensions

The rheology of nanoparticle suspensions for nanoparticles of various shapes with equal mass is studied using molecular dynamics simulations. The equilibrium structure and the response to imposed shear are analyzed for suspensions of spheres, rods, plates, and jacks in an explicit solvent for both charged and uncharged nanoparticles. For the volume fraction studied, ?$\phi_{vf}=0.075$, the uncharged systems are all in their isotropic phase and the viscosity is only weakly dependent on shape for spheres, rods, and plate whereas for the jacks the viscosity is an order of magnitude larger than for the other three shapes. The introduction of charge increases the viscosity for all four nanoparticle shapes with the increase being the largest for rods and plates. The presence of a repulsive charge between the particles decreases the amount of stress reduction that can be achieved by particle reorientation.Comment: 15 pages, 9 figures, in pres

A Preliminary Analysis of Precipitation Properties and Processes during NASA GPM IFloodS

The Iowa Flood Studies (IFloodS) is a NASA Global Precipitation Measurement (GPM) ground measurement campaign, which took place in eastern Iowa from May 1 to June 15, 2013. The goals of the field campaign were to collect detailed measurements of surface precipitation using ground instruments and advanced weather radars while simultaneously collecting data from satellites passing overhead. Data collected by the radars and other ground instruments, such as disdrometers and rain gauges, will be used to characterize precipitation properties throughout the vertical column, including the precipitation type (e.g., rain, graupel, hail, aggregates, ice crystals), precipitation amounts (e.g., rain rate), and the size and shape of raindrops. The impact of physical processes, such as aggregation, melting, breakup and coalescence on the measured liquid and ice precipitation properties will be investigated. These ground observations will ultimately be used to improve rainfall estimates from satellites and in particular the algorithms that interpret raw data for the upcoming GPM mission's Core Observatory satellite, which launches in 2014. The various precipitation data collected will eventually be used as input to flood forecasting models in an effort to improve capabilities and test the utility and limitations of satellite precipitation data for flood forecasting. In this preliminary study, the focus will be on analysis of NASA NPOL (Sband, polarimetric) radar (e.g., radar reflectivity, differential reflectivity, differential phase, correlation coefficient) and NASA 2D Video Disdrometers (2DVDs) measurements. Quality control and processing of the radar and disdrometer data sets will be outlined. In analyzing preliminary cases, particular emphasis will be placed on 1) documenting the evolution of the rain drop size distribution (DSD) as a function of column melting processes and 2) assessing the impact of range on groundbased polarimetric radar estimates of DSD properties

Biomarkers of aging associated with past treatments in breast cancer survivors.

Radiation and chemotherapy are effective treatments for cancer, but are also toxic to healthy cells. Little is known about whether prior exposure to these treatments is related to markers of cellular aging years later in breast cancer survivors. We examined whether past exposure to chemotherapy and/or radiation treatment was associated with DNA damage, telomerase activity, and telomere length 3-6 years after completion of primary treatments in breast cancer survivors (stage 0-IIIA breast cancer at diagnosis). We also examined the relationship of these cellular aging markers with plasma levels of Interleukin (IL)-6, soluble TNF-receptor-II (sTNF-RII), and C-reactive protein (CRP). Ninety-four women (36.4-69.5 years; 80% white) were evaluated. Analyses adjusting for age, race, BMI, and years from last treatment found that women who had prior exposure to chemotherapy and/or radiation compared to women who had previously received surgery alone were more likely to have higher levels of DNA damage (P = .02) and lower telomerase activity (P = .02), but did not have differences in telomere length. More DNA damage and lower telomerase were each associated with higher levels of sTNF-RII (P's < .05). We found that exposure to chemotherapy and/or radiation 3-6 years prior was associated with markers of cellular aging, including higher DNA damage and lower telomerase activity, in post-treatment breast cancer survivors. Furthermore, these measures were associated with elevated inflammatory activation, as indexed by sTNF-RII. Given that these differences were observed many years after the treatment, the findings suggest a long lasting effect of chemotherapy and/or radiation exposure

An Experimental Study of the Rainfall Variability Within TRMM/GPM Precipitation Radar and Microwave Sensor Instantaneous Field of View During MC3E

Dual tipping bucket gauges were operated at 16 sites in support of ground based precipitation measurements during Mid-latitude Continental Convective Clouds Experiment (MC3E). The experiment is conducted in North Central Oklahoma from April 22 through June 6, 2011. The gauge sites were distributed around Atmospheric Radiation Measurement (ARM) Climate Research facility where the minimum and maximum separation distances ranged from 1 to 12 km. This study investigates the rainfall variability by employing the stretched exponential function. It will focus on the quantitative assessment of the partial beam of the experiment area in both convective and stratiform rain. The parameters of the exponential function will also be determined for various events. This study is unique for two reasons. First is the existing gauge setup and the second is the highly convective nature of the events with rain rates well above 100 mm h-1 for 20 minutes. We will compare the findings with previous studies

Flies associated with floral canopies of the new oilseed crop, pennycress, in the Midwestern U.S.A.

Flies are frequent visitors to flowers of many species of plants within the mustard family (Brassicaceae). They derive nutrition from these flowers, and some fly species are pollinators. Field pennycress (Thlaspi arvense) is a mustard species that is being developed as a new “cash cover crop,” i.e., an autumn-sown cover crop whose oil-rich seeds can be harvested profitably in spring. Although pennycress is largely wind- and self-pollinated, its flowers also attract insect visitors. However, the extent of visitation to pennycress flowers by flies remains largely unknown, especially the identities of those flies. Thus, we examined flies associated with pennycress flowering canopies at five site-years in Illinois and Minnesota. The number of fly species averaged 16 per site-year. Hover flies (Syrphidae) were common visitors to pennycress flowering canopies, representing 24% of all Diptera collected. Toxomerus marginatus (margined calligrapher), whose larvae are aphid predators, was especially abundant within this family. However, the most common flies detected were Delia spp. (Anthomyiidae, root maggot flies), which averaged 51% of all flies collected. Adults of these flies are known pollinators, but their larvae also are pests that can damage seedlings of common summer crops. Although seedling damage to plants that are double- or relay-cropped (i.e., inter-seeded in spring) with pennycress has not been observed yet, close observation of this insect group and its effects may be needed if pennycress is widely sown in the future as a cash cover crop

Spatial Correlation of Rain Drop Size Distribution from Polarimetric Radar and 2D-Video Disdrometers

Spatial correlations of two of the main rain drop-size distribution (DSD) parameters - namely the median-volume diameter (Do) and the normalized intercept parameter (Nw) - as well as rainfall rate (R) are determined from polarimetric radar measurements, with added information from 2D video disdrometer (2DVD) data. Two cases have been considered, (i) a widespread, long-duration rain event in Huntsville, Alabama, and (ii) an event with localized intense rain-cells within a convection line which occurred during the MC3E campaign. For the first case, data from a C-band polarimetric radar (ARMOR) were utilized, with two 2DVDs acting as ground-truth , both being located at the same site 15 km from the radar. The radar was operated in a special near-dwelling mode over the 2DVDs. In the second case, data from an S-band polarimetric radar (NPOL) data were utilized, with at least five 2DVDs located between 20 and 30 km from the radar. In both rain event cases, comparisons of Do, log10(Nw) and R were made between radar derived estimates and 2DVD-based measurements, and were found to be in good agreement, and in both cases, the radar data were subsequently used to determine the spatial correlations For the first case, the spatial decorrelation distance was found to be smallest for R (4.5 km), and largest fo Do (8.2 km). For log10(Nw) it was 7.2 km (Fig. 1). For the second case, the corresponding decorrelation distances were somewhat smaller but had a directional dependence. In Fig. 2, we show an example of Do comparisons between NPOL based estimates and 1-minute DSD based estimates from one of the five 2DVDs

The Lantern Vol. 65, No. 1, Fall 1997

• The Substitute • Style • The Greatest of These • The No-Zone • The Smell of Flowers • The Wine Cellar • Last Rites • The Missing Sock • In Loving Memory • New Jersey • Let\u27s Play a Game • Track Eleven • U Cab Chan Kina • Confined • Ekphrasis from Ursinus Campus in Snow • Five Elements • A Puzzle • Wh-?https://digitalcommons.ursinus.edu/lantern/1151/thumbnail.jp