Twenty-First Century Research Needs in Electrostatic Processes Applied to Industry and Medicine

From the early century Nobel Prize winning (1923) experiments with charged oil droplets, resulting in the discovery of the elementary electronic charge by Robert Millikan, to the early 21st century Nobel Prize (2002) awarded to John Fenn for his invention of electrospray ionization mass spectroscopy and its applications to proteomics, electrostatic processes have been successfully applied to many areas of industry and medicine. Generation, transport, deposition, separation, analysis, and control of charged particles involved in the four states of matter: solid, liquid, gas, and plasma are of interest in many industrial and biomedical processes. In this paper, we briefly discuss some of the applications and research needs involving charged particles in industrial and medical applications including: (1) Generation and deposition of unipolarly charged dry powder without the presence of ions or excessive ozone, (2) Control of tribocharging process for consistent and reliable charging, (3) Thin film (less than 25 micrometers) powder coating and Powder coating on insulative surfaces, (4) Fluidization and dispersion of fine powders, (5) Mitigation of Mars dust, (6) Effect of particle charge on the lung deposition of inhaled medical aerosols, (7) Nanoparticle deposition, and (8) Plasma/Corona discharge processes. A brief discussion on the measurements of charged particles and suggestions for research needs are also included

Thermodynamic properties and structural stability of thorium dioxide

Using density functional theory (DFT) calculations, we have systematically investigated the thermodynamic properties and structural stabilities of thorium dioxide (ThO$_2$). Based on the calculated phonon dispersion curves, we calculate the thermal expansion coefficient, bulk modulus, and heat capacities at different temperatures for ThO$_2$ under the quasi-harmonic approximation. All the results are in good agreement with corresponding experiments proving the validity of our methods. Our theoretical studies can help people more clearly understand the thermodynamic behaviors of ThO$_2$ at different temperatures. In addition, we have also studied possible defect formations and diffusion behaviors of helium in ThO$_2$, to discuss its structural stability. It is found that in intrinsic ThO$_2$ without any Fermi energy shifts, the interstitial Th$_i^{4+}$ defect other than oxygen or thorium vacancies, interstitial oxygen, and any kinds of Frenkel pairs, is most probable to form with an energy release of 1.74 eV. However, after upshifting the Fermi energy, the formation of the other defects also becomes possible. For helium diffusion, we find that only through the thorium vacancy can it happen with the small energy barrier of 0.52 eV. Otherwise, helium atoms can hardly incorporate or diffuse in ThO$_2$. Our results indicate that people should prevent upshifts of the Fermi energy of ThO$_2$ to avoid the formation of thorium vacancies and so as to prevent helium caused damages.Comment: 11 pages, 11 figure

Response to fertilizer nitrogen and water of post-rainy season sorghum on a Vertisol. 1. Biomass and light interception

Sorghum cv. SPH-280 was grown in the post-rainy season at ICRISAT (Andhra Pradesh, India) with and without irrigation and at six rates of nitrogen from zero to 150 kg/ha applied before sowing. The biomass of top components was measured weekly and of roots every 2 weeks. Interception of solar radiation was monitored continuously in all treatments. Leaf expansion was strongly influenced both by water and by N, whereas specific leaf area was almost independent of treatment. In the irrigated treatment, the Biomass Radiation Coefficient (e) for the main growth period was almost independent of N application at 1.3-1.4 g/MJ and was also independent of leaf N. In consequence, the main source of differences in yield was a decrease in radiation interception with decreasing N. In contrast, without irrigation, biomass, yield, e and leaf N were all maximal at 60 kg/ha N. At 33 days after emergence (DAE), root mass was almost independent of N whether water had been applied or not, but was somewhat smaller with irrigation. Later, root, leaf, and panicle mass all responded to N and to water, but stem mass was unresponsive to N with irrigation. There was evidence of translocation from stem to grain in most treatments. With irrigation, a maximum grain yield of 4.8 t/ha was obtained at 150 kg/ha N and without irrigation the maximum was 3.2 t/ha at 90 kg/ha

Choosing and Using a Plant DNA Barcode

The main aim of DNA barcoding is to establish a shared community resource of DNA sequences that can be used for organismal identification and taxonomic clarification. This approach was successfully pioneered in animals using a portion of the cytochrome oxidase 1 (CO1) mitochondrial gene. In plants, establishing a standardized DNA barcoding system has been more challenging. In this paper, we review the process of selecting and refining a plant barcode; evaluate the factors which influence the discriminatory power of the approach; describe some early applications of plant barcoding and summarise major emerging projects; and outline tool development that will be necessary for plant DNA barcoding to advance

Thermal diffusivity and thermal conductivity studies on europium, gadolinium and lanthanum pyrohafnates

The measurement of thermal properties forms an important aspect of the research on materials of interest in nuclear technology. In particular thermal diffusivity and thermal conductivity data are of relevance in the quantitative evaluation of the heat flow and temperature variations in materials operating at high temperatures. Since isotopes of several lanthanide elements and hafnium have high neutron absorption cross-sections, their compounds are potential candidates for control rod applications. In this paper, our studies on rare earth pyrohafnates R2Hf2O7 (where R represents a rare earth), which are 2:1 solid solutions of hafnium dioxide and a rare earth sesquioxide, are reported. Thermal diffusivity and thermal conductivity data obtained on europium, gadolinium and lanthanum pyrohafnates, employing a laser flash apparatus set up in our laboratory and covering the temperature range 600-1300 K, are presented

Thermal conductivity of rare earth-uranium ternary oxides of the type RE<SUB>6</SUB>UO<SUB>12</SUB>

The knowledge of thermophysical properties of the rare earth uranium ternary oxides of the type RE6UO12 (RE=La, Gd and Dy) is essential to understand the fuel performance during reactor operation and for modeling fuel behavior. Literature on the high temperature properties of this compound is not available and there is no report at all on the thermal conductivity of these compounds. Hence a study of thermal conductivity of this compound has been taken up. The compounds were synthesized by a solution combustion method using metal nitrates and urea. Thermal diffusivity of these compounds was measured by the laser flash method in the temperature range 673-1373 K. The specific heat data was computed using Neumann-Kopp's law. Thermal conductivity was calculated using the measured thermal diffusivity value, density and specific heat data for different temperatures. The temperature dependence of thermal conductivity and the implication of structural aspects of these compounds on the data are discussed here

Stormtime Variation of TEC over Walt air

31-34TEC measurements made at Waltair (17.7°N; 83.3°E) using the telemetry signal from the ETS-II geostationary satellite at 136•1123 MHz are used to study the stormtime variation of total electron content (TEC) during 21 SC type of geomagnetic storms pertaining to the period Mar. 1978- Feb. 1979. It is found, from these measurements, that the effect of a geomagnetic storm on TEC is to increase in the case of daytime storms and decrease in the case of nighttime storms. The percentage increase is proportional to the main phase magnitude. During winter the increase in TEC is more and during summer the increase is less and delayed

A study of the non-stoichiometry in U<SUB>3</SUB>O<SUB>8</SUB>

Measurements of the oxygen-to-uranium ratio in U3O8 were performed using two independent methods, namely thermogravimetry and wet chemical analysis by cerimetry. The O/U variations in U3O8 were delineated as a function of temperature in the range 450-900&#176;C. The experimental conditions for the attainment of the stoichiometric state were also examined

Bridging a High School Science Fair Experience with First Year Undergraduate Research: Using the E-SPART Analyzer to Determine Electrostatic Charge Properties of Compositionally Varied Rock Dust Particles as Terrestrial Analogues to Mars Materials

NASA missions to Mars confirm presence of surficial particles, as well as dramatic periods of aeolian reworking. Dust deposition on, or infiltration into, exploration equipment such as spacecraft, robotic explorers, solar panel power supplies, and even spacesuits, can pose significant problems such as diminished power collection, short circuits / discharges, and added weight. We report results conducted initially as a science fair project and a study now part of a first year University undergraduate research experience