A Time-of-Flight Mass Spectrometer for Upper Atmospheric Measurements

The mesosphere-lower thermosphere (MLT) is perhaps the least understood region of the earth’s atmosphere due to the difficulty of obtaining in-situ measurements. Access to the MLT is limited to high-speed sounding rockets for brief periods of at most a few minutes. Because of its wide mass range and high scan rate, Time-of-flight mass spectrometry (TOF-MS) has potential to resolve thin layers of diverse species in the MLT. However, because ambient pressures can reach into the millitorr range, TOF-MS has rarely been applied in the MLT due to its dependence on high voltages and microchannel plate (MCP) detectors. A novel dual mode, compact axial TOF-MS suitable for deployment aboard a sounding rocket for measurements in the MLT is presented. This TOF-MS is capable of operating in either a standard TOF mode or in a multiplexing mode to achieve high measurement duty cycles with a theoretically unlimited mass range. Experimental data is presented demonstrating successful MCP operation in a variety of environments including O2, N2, and air at pressures into the low millitor range. Also presented are results from extensive simulation and modeling efforts to approximate the in-flight operating environment of the TOF-MS. Gas flow modeling in a typical MLT environment is performed using the Direct Simulation Monte Carlo (DSMC) method. Standard gas flow equations are combined with DSMC results to estimate pressures inside the TOF-MS. Modeling, simulations and experimental work combine to demonstrate the potential of the new dual mode TOF-MS for deployment in the upper atmosphere

Microbial-Physical Synthesis of Fe and Fe3O4 Magnetic Nanoparticles Using Aspergillus niger YESM1 and Supercritical Condition of Ethanol

Magnetic Fe and Fe3O4 (magnetite) nanoparticles are successfully synthesized using Aspergillus niger YESM 1 and supercritical condition of liquids. Aspergillus niger is used for decomposition of FeSO4 and FeCl3 to FeS and Fe2O3, respectively. The produced particles are exposed to supercritical condition of ethanol for 1 hour at 300∘ C and pressure of 850 psi. The phase structure and the morphology measurements yield pure iron and major Fe3O4 spherical nanoparticles with average size of 18 and 50 nm, respectively. The crystal size amounts to 9 nm for Fe and 8 nm for Fe3O4. The magnetic properties are measured to exhibit superparamagneticand ferromagnetic-like behaviors for Fe and Fe3O4 nanoparticles, respectively. The saturation magnetization amounts to 112 and 68 emu/g for Fe and Fe3O4, respectively. The obtained results open new route for using the biophysical method for large-scale production of highly magnetic nanoparticles to be used for biomedical applications

The Phytoplankton of Lake Wawasee, Kosciusko County, Indiana

Lake Wawasee located at Syracuse, Indiana, is the largest body of water in the state. It has an area of 2,618 acres, a maximum depth of 68 feet and a shore line of approximately 22 miles.To our knowledge, the only paper published in which phytoplankters of Lake Wawasee are mentioned appeared in 1896. Those were Ceratium hirundinella, Rivularia and various forms of Palmella

Controlled synthesis of superparamagnetic iron-oxide nanoparticles by phase transformation

A synthesis procedure for generating a uniform distribution of iron-oxide nanoparticles from an amorphous precursor is reported. The investigation suggests no evidence of the formation of unwanted surface oxide layers, internal stress, and multiple phases. This is likely because the physical properties of the diffusion fields surrounding the nanoparticles are self-limiting by Fe(II) depletion. Inside the diffusion field surrounding the nucleation site, decreasing Fe(II) concentration results in a decrease in the diffusion rate that continues to decrease until self-limiting kinetic arrest occurs. The initial Fe(II) concentration is established by reducing a system abundant in Fe(III) by means of exposure to CO/CO2 gas at high temperature

Wavelength Control for a Potassium Resonance Lidar

An important ground-based way to measure temperatures and winds in the transition region between the upper mesosphere and lower thermosphere (80 to 105 km) is with a resonance-scatter lidar. An alexandrite laser, with a wavelength in the near infrared at 770 nm, is being added to the Atmospheric Lidar Observatory to make this type of observation of potassium. These observations will complement those that have been made for many years with the green Rayleigh-scatter lidar. For these resonance-scatter observations it is necessary to accurately and precisely control the laser wavelength. The intent is to carefully step across the 4 pm (2 GHz) wide potassium spectrum (Figure 1). The width of the spectrum has to be determined within 6.0 fm (3.0 MHz ) to obtain a temperature precision of ±5 K. The Doppler shift of the spectrum has to be determined within 5.1 fm (2.6 MHz) to obtain a wind-speed precision of ±2 m/s. This project is a step in that direction. It involves developing a method, based around a scanning Fabry-Perot interferometer (FPI), to control a CW seed laser that, in turn, controls the alexandrite laser

CC159 Grain Sorghum : Should I Dry and Store or Sell at Harvest?

Campaign circular 159 provides information for decision making whether to dry and store, or sell the grain sorghum

Fatigue crack initiation and small crack growth in several airframe alloys

The growth of naturally-initiated small cracks under a variety of constant amplitude and variable amplitude load sequences is examined for several airframe materials: the conventional aluminum alloys, 2024-T3 and 7075-T6, the aluminum-lithium alloy, 2090-T8E41, and 4340 steel. Loading conditions investigated include constant amplitude loading at R = 0.5, 0, -1 and -2 and the variable amplitude sequences FALSTAFF, Mini-TWIST and FELIX/28. Crack growth was measured at the root of semicircular edge notches using acetate replicas. Crack growth rates are compared on a stress intensity factor basis, to those for large cracks to evaluate the extent of the small crack effect in each alloy. In addition, the various alloys are compared on a crack initiation and crack growth morphology basis

String Cosmology in Anisotropic Bianchi-II Space-time

The present study deals with a spatially homogeneous and anisotropic Bianchi-II cosmological model representing massive strings. The energy-momentum tensor, as formulated by Letelier (1983), has been used to construct a massive string cosmological model for which the expansion scalar is proportional to one of the components of shear tensor. The Einstein's field equations have been solved by applying a variation law for generalized Hubble's parameter that yields a constant value of deceleration parameter in Bianchi-II space-time. A comparative study of accelerating and decelerating modes of the evolution of universe has been carried out in the presence of string scenario. The study reveals that massive strings dominate the early Universe. The strings eventually disappear from the Universe for sufficiently large times, which is in agreement with the current astronomical observations.Comment: 11 pages, 6 figures (To appear in Mod. Phys. Lett. A) In this version, the cosmic string has been directed along z-direction and the resultant field equations have been solved exactl

What the Pilgrim fathers left behind them

Plymouth tercentenary lecture delivered at the Rice Institute, October 14, 1920 by Sir Arthur Everett Shipley, G.B.E., F.R.S., ScD. (Princeton), LL.D. (Michigan), Master of Christ's College, Cambridge

A Superluminal Subway: The Krasnikov Tube

The ``warp drive'' metric recently presented by Alcubierre has the problem that an observer at the center of the warp bubble is causally separated from the outer edge of the bubble wall. Hence such an observer can neither create a warp bubble on demand nor control one once it has been created. In addition, such a bubble requires negative energy densities. One might hope that elimination of the first problem might ameliorate the second as well. We analyze and generalize a metric, originally proposed by Krasnikov for two spacetime dimensions, which does not suffer from the first difficulty. As a consequence, the Krasnikov metric has the interesting property that although the time for a one-way trip to a distant star cannot be shortened, the time for a round trip, as measured by clocks on Earth, can be made arbitrarily short. In our four dimensional extension of this metric, a ``tube'' is constructed along the path of an outbound spaceship, which connects the Earth and the star. Inside the tube spacetime is flat, but the light cones are opened out so as to allow superluminal travel in one direction. We show that, although a single Krasnikov tube does not involve closed timelike curves, a time machine can be constructed with a system of two non-overlapping tubes. Furthermore, it is demonstrated that Krasnikov tubes, like warp bubbles and traversable wormholes, also involve unphysically thin layers of negative energy density, as well as large total negative energies, and therefore probably cannot be realized in practice.Comment: 20 pages, LATEX, 5 eps figures, uses \eps