Sputtering yield measurements at glancing incidence using a quartz crystal microbalance

Low energy sputtering yields at grazing incidence have been investigated experimentally using a quartz crystal microbalance (QCM) technique. This method involved precoating the QCM with a thin film of the desired target material and relating the resonance frequency shift directly to mass loss during ion bombardment. A highly focused, low divergence ion beam provided a well defined incidence angle. Focusing most of the ion current on the center of the target allowed for higher sensitivity by taking into account the radial mass sensitivity of the QCM. Measurements of Mo, Cu, and W sputtering yields were taken for low energy (80–1000 eV) Xe+ and Ar+ to validate this experimental method. The target films ranged from 3.5 to 8.0 µm in thickness and were deposited so that their crystal structure and density would match those of the bulk material as closely as possible. These properties were characterized using a combination of scanning electron microscope imagery, profilometry, and x-ray diffraction. At normal incidence, the sputtering yields demonstrated satisfactory agreement with previously published work. At angles of incidence up to 40° off normal, the data agreed well with predictions from existing theoretical models. Sputtering yields were found to increase by a factor of 1.6 over this range. The optimum angle for sputtering occurred at 55°, after which the yields rapidly decreased. Measurements were taken up to 80° from the surface normal

Menstrual Hygiene Product Use and the Incidence of Abnormal Papanicolaou Smear Results

Today the majority of females fifteen years and older have used tampons. Since their introduction in 1933, tampons have changed greatly in composition: more absorbent synthetic fibers have replaced natural fibers, plastic applicators have joined cardboard, and some contain a fragrance. While changes in vaginal mucosa including inflammatory changes, lacerations, and micro-ulcerations as a result of tampon use have been documented, no research examining the use of menstrual hygiene products and their effect on cervical cytology was located. The purpose of this study was to examine the association between menstrual hygiene product use and the incidence of abnormal Pap smear results, specifically that of benign cellular inflammatory changes and/or atypical squamous cell of undetermined significance (ASCUS). The Theory of Nursing as Human Science and Human Care as proposed by Jean Watson (1979) was the theoretical framework for this study. Data were collected by chart audit review of 250 women, ages 14 to 36, who sought Pap smear screening at a Midwestern family planning clinic. The data collection instrument was designed by the researcher. Data were analyzed using the Statistical Package for the Social Sciences (SPSS-X). The association in Pap smear result by tampon applicator use, analyzed using Pearson Chi square, was . . 2 found to be statistically significant (X =18.53; df=4; p=0.003). The difference in Pap smear result by type of 2 tampon was also statistically significant (X =48.06; df=3; p=0.000). Reported use of plastic and/or deodorized tampon use by those subjects with inflammatory changes and/or ASCUS Pap results was three times that of those reporting cardboard applicator, non-deodorized tampon or sanitary pad use

Godel-type space-time metrics

A simple group theoretic derivation is given of the family of space-time metrics with isometry group SO(2,1) X SO(2) X R first described by Godel, of which the Godel stationary cosmological solution is the member with a perfect-fluid stress-energy tensor. Other members of the family are shown to be interpretable as cosmological solutions with a electrically charged perfect fluid and a magnetic field.Comment: Heavly rewritten respect to the orginal version, corrected some typos due to files transfer in the last submitted versio

Why and how much the Brouwer's Fixed Point Theorem fails in noncompact setting?

The celebrated Brouwer\u2019s Fixed Point Theorem is dated in 1912. Its extension to compact set setting in Banach spaces due to Schauder appeared in 1930. Immediately it raised the question whether the Theorem can be extended to noncompact setting. The works of Kakutani, Klee, Benyamini and Sterfeld, Sternfeld and Lim solved the qualitative part of the problem. Lack of compactness makes the statement of the theorem false. However, there are some quantitative aspects of the question. The two basic are called minimal displacement problem, and optimal retraction problem. The aim of this article is to present the historical back ground and possibly, up to date state of investigations in this field. A list of open problems with comments will be discussed

Design and Preliminary Testing Plan of Electronegative Ion Thruster

Electronegative ion thrusters are a new iteration of existing gridded ion thruster technology differentiated by their ability to produce and accelerate both positive and negative ions. The primary motivations for electronegative ion thruster development include the elimination of lifetime-limiting cathodes from a thruster system and the ability to generate appreciable thrust through the acceleration of both positive or negative-charged ions. Proof-of-concept testing of the PEGASES (Plasma Propulsion with Electronegative GASES) thruster demonstrated the production of positively and negatively-charged ions (argon and sulfur hexafluoride, respectively) in an RF discharge and the subsequent acceleration of each charge species through the application of a time-varying electric field to a pair of metallic grids similar to those found in gridded ion thrusters. Leveraging the knowledge gained through experiments with the PEGASES I and II prototypes, the MINT (Marshall's Ion-ioN Thruster) is being developed to provide a platform for additional electronegative thruster proof-of-concept validation testing including direct thrust measurements. The design criteria used in designing the MINT are outlined and the planned tests that will be used to characterize the performance of the prototype are described

Small-scale contact angle mapping on undisturbed soil surfaces

Research of the last years pointed out that most soils are neither completely hydrophilic nor hydrophobic, but exhibit a subcritical level of water repellency (i.e. contact angle, CA > 0 degrees and 300 mu m using drop volumes down to 0.1 mu L. Geostatistical evaluation showed that the measurement grid scale is below the range of spatial dependency for droplets of 1 mu L volume, but not for measurements on single grains (pure nugget effect). Results show further that the small-scale differences in wettability, especially for CA < 90 degrees, cannot be detected by the conventional WDPT test. From these findings it can be concluded that the proposed technique allows the identification of small-scale variations in wettability that may promote the formation of heterogeneous flow fields and moisture patterns in soil under unsaturated conditions.DFG/SPP/1315DFG/BA1359/9-