2,658 research outputs found
Solar total irradiance in cycle 23
The apparently unusual behaviour of the TSI during the most recent minimum of
solar activity has been interpreted as evidence against solar surface magnetism
as the main driver of the secular change in the TSI. We test claims that the
evolution of the solar surface magnetic field does not reproduce the observed
TSI in cycle 23. We use sensitive, 60-minute averaged MDI magnetograms and
quasi-simultaneous continuum images as an input to our SATIRE-S model and
calculate the TSI variation over cycle 23, sampled roughly twice-monthly. The
computed TSI is then compared to the PMOD composite of TSI measurements and to
the data from two individual instruments, SORCE/TIM and UARS/ACRIM II, that
monitored the TSI during the declining phase of cycle 23 and over the previous
minimum in 1996, respectively. Excellent agreement is found between the trends
shown by the model and almost all sets of measurements. The only exception is
the early, i.e. 1996 to 1998, PMOD data. Whereas the agreement between the
model and the PMOD composite over the period 1999-2009 is almost perfect, the
modelled TSI shows a steeper increase between 1996 and 1999 than implied by the
PMOD composite. On the other hand, the steeper trend in the model agrees
remarkably well with the ACRIM II data. A closer look at the VIRGO data, that
make the basis of the PMOD composite after 1996, reveals that only one of the
two VIRGO instruments, the PMO6V, shows the shallower trend present in the
composite, whereas the DIARAD measurements indicate a steeper trend. We
conclude that (1) the sensitivity changes of the PMO6V radiometers within VIRGO
during the first two years have very likely not been correctly evaluated, and
that (2) the TSI variations over cycle 23 and the change in the TSI levels
between the minima in 1996 and 2008 are consistent with the solar surface
magnetism mechanism
Polymer Dissolution Model: An Energy Adaptation Of The Critical Ionization Theory
The current scale of features size in the microelectronics industry has reached the point where molecular level interactions affect process fidelity and produce excursions from the continuum world like line edge roughness (LER). Here we present a 3D molecular level model based on the adaptation of the critical ionization (CI) theory using a fundamental interaction energy approach. The model asserts that it is the favorable interaction between the ionized part of the polymer and the developer solution which renders the polymer soluble. Dynamic Monte Carlo methods were used in the current model to study the polymer dissolution phenomenon. The surface ionization was captured by employing an electric double layer at the interface, and polymer motion was simulated using the Metropolis algorithm. The approximated interaction parameters, for different species in the system, were obtained experimentally and used to calibrate the simulated dissolution rate response to polymer molecular weight and developer concentration. The predicted response is in good agreement with experimental dissolution rate data. The simulation results support the premise of the CI theory and provide an insight into the CI model from a new prospective. This model may provide a means to study the contribution of development to LER and other related defects based on molecular level interactions between distinct components in the polymer and the developer.Chemical Engineerin
Lower Extremity Strength and Mechanics During Jumping in Women With Patellofemoral Pain
Context: Lower extremity (LE) weakness might be associated with altered mechanics during weight bearing in subjects with patellofemoral pain syndrome (PFPS). Objective: To analyze LE strength, mechanics, and the association between these variables among women with and without PFPS during a simulated athletic task. Design: Case control. Setting: Motion-analysis laboratory. Subjects: 20 women with PFPS and 20 healthy women. Main Outcome Measures: Peak isometric lateral trunk-flexion, hipabduction, hip external-rotation, knee-flexion, and knee-extension strength, as well as hip- and knee-joint excursions and angular impulses during single-leg jumps. Results: PFPS subjects produced less hip-abduction, hip external-rotation, and trunk lateral- flexion force than the control group. The PFPS group also demonstrated greater hipadduction excursion and hip-abduction impulses. The association between the strength measurements and LE mechanics was low. Conclusions: Women with PFPS demonstrate specific weaknesses and altered LE mechanics. Weakness is not, however, highly correlated with observed differences in mechanics. ABSTRACT FROM AUTHO
Attractants for Synanthropic Flies. 2. Response Patterns of House Flies to Attractive Baits on Poultry Ranches
A proteinaceous attractant, prepared by freeze-drying fermented whole egg solids, was found to attract Musca domestica L. and other synanthropic Diptera. In field experiments, a mixture of 2 g of the attractant and 2 g of dichlorvos sugar-bait increased fly collection two-fold on manure substrate in trays set on the ground and three-fold in suspended bait units over the sugar-toxicant bait alone. This increase was due primarily to the increased response of nulliparous and parous females in which vitellogenesis was about to occur. Attractancy of the bait declined sharply after 48 hours of field exposure. The location of bait stations significantly affected the number, sex ratio, and female age structure of the flies collected. Stations collecting the greatest number of flies were generally situated at the ends of the cage rows in sunlight-shade border areas. Fly collections from areas of greatest fly activity were characterized by a high proportion of hoth nulliparous and parous protein-searching females, and the sex ratio in these high-activity zones approached 1. East-west and north-south preferences of certain female age groups were manifested in the collection
Bait Units for Collection of House Flies
Lurtox™4 is a proteinaceous attractant for Musca domestica L. and other synanthropic Diptera (Mulla et al. 1973: Willson and Mulla 1973a) and is easily mixed with commercial poison sugar baits. The mixture of Lurtox and dichlorvos sugar bait (50:50 by wt) can be administered in measurable quantities into compact bait units where dead flies can be easily recovered for counting and for other studies. While developing Lurtox for control of Hippelates eye gnats, Mulla et al. (1973) found that moisture was essential for the emanation of the volatile attractants contained in the bait. Therefore, if the prevalent humidity level is not sufficient to activate the attractant, the bait unit designed for use with the bait mixture should include a moisture sourc
Modeling Solar Lyman Alpha Irradiance
Solar Lyman alpha irradiance is estimated from various solar indices using linear regression analyses. Models developed with multiple linear regression analysis, including daily values and 81-day running means of solar indices, predict reasonably well both the short- and long-term variations observed in Lyman alpha. It is shown that the full disk equivalent width of the He line at 1083 nm offers the best proxy for Lyman alpha, and that the total irradiance corrected for sunspot effect also has a high correlation with Lyman alpha
Combining visibilities from the Giant Meterwave Radio Telescope and the Nancay Radio Heliograph: High dynamic range snapshot images of the solar corona at 327 MHz
We report first results from an ongoing program of combining visibilities
from the Giant Meterwave Radio Telescope (GMRT) and the Nancay Radio Heliograph
(NRH) to produce composite snapshot images of the sun at meter wavelengths. We
describe the data processing, including a specific multi-scale CLEAN algorithm.
We present results of a) simulations for two models of the sun at 327 MHz, with
differing complexity b) observations of a complex noise storm on the sun at 327
MHz on Aug 27 2002. Our results illustrate the capacity of this method to
produce high dynamic range snapshot images when the solar corona has structures
with scales ranging from the image resolution of 49" to the size of the whole
sun.
We find that we cannot obtain reliable snapshot images for complex objects
when the visibilities are sparsely sampled.Comment: Accepted for publication in Astronomy & Astrophysics. Version with
high resolution figures available from
ftp://ftp.iucaa.ernet.in/in.coming/gmrtnr
How the Dark Horse Came in: Portland State University Library Acquires Dark Horse Comics Archive
The article reports on the acquisition made by the Portland State University (PSU) on the archives of Dark Horse Comics Inc. The acquisition is done after PSU alumnus and founder of Dark Horse Comics Mark Richardson donated multiple copies of the past issues of their publication and succeeding copies of the publication. The donation is also for the purpose of preserving the publication in the university library. The donated publication is also expected to be used by researchers as a destination resource in popular culture, gender studies, and sequential art. Donating copies to the library, Richardson also expects to create an ideal atmosphere for creative professionals as well as a sense of ownership for Dark Horse creators
Experimental study on a single cement-fracture using CO\u3csub\u3e2\u3c/sub\u3e rich brine
The efficiency of Carbon Capture and Storage (CCS) projects is directly related to the long term sealing efficiency of barrier systems and of wellbore cement in wellbores penetrating storage reservoirs. The microfractures inside the wellbore cement provide possible pathways for CO leakage to the surface and/or fresh water aquifers, impairing the long-term containment of CO in the subsurface. The purpose of this experimental study is to understand the dynamic alteration process in the cement caused by the acidic brine. The first experiment, at ambient temperature and pressure, was conducted by flowing CO -rich brine through 1 in. by 2 in. (25.4 mm by 50.8 mm) cement cores for 4 and 8 weeks durations. The second experiment was a 4 weeks long flow-through experiment conducted at ambient conditions using a 1 in by 12 in.(25.4 mm by 304.8 mm) cement core and CO -rich brine with a core flooding system under 600 psi (4.13 MPa) confining stress. Post-experiment material analysis from both experiments confirmed leaching of Ca from reacted cement, as reported in literature. However for the first time, porosity of the reacted regions was semi-quantified applying micro-CT images. © 2010 Elsevier Ltd. © 2011 Published by Elsevier Ltd. 2 2 2 2 2
- …