3,396 research outputs found
Fuse-holder concept expedites electronic component changes
Mounting circuit components in fuse holders facilitates component changing and extends component life with an estimated fifty percent saving of breadboard test time. Glass sleeves of the fuse holders allow easy component identification
Coded photographic proof paper could serve as convenient densitometer
Standard print-out proofing paper, preprinted with an identifying code, serves as convenient densitometer. Exposure to light darkens the paper and gives a measure of the density of the resultant photographic image or the total amount of exposure sustained by the paper
A Visit to the Battlefield
This piece was transcribed and edited by Michael J. Birkner and Richard E. Winslow.
With fighting concluded at Gettysburg on July 3, 1863, the enormous task of burying the dead, treating the wounded, and rehabilitating the town began in earnest. Although Gettysburg looked and smelled worse than it ever had or ever would again, thousands of people arrived on the battlefield in the days and weeks following General Robert E. Lee\u27s retreat. Some came to minister to the sick and reclaim the bodies of neighbors and loved ones; others scavenged souvenirs of the battle. Of the many visits to the battlefield in July 1863, few have been more affectingly described than the account of Joseph H. Foster of Portsmouth, New Hampshire.
In the document reprinted below, of a speech Foster delivered at the Unitarian Sabbath School in Portsmouth on July 26, 1863, he describes a brief trip to Gettysburg from which he had just returned. His objective in going to Gettysburg was straightforward: he wanted to locate the body of his neighbor and friend Henry L. Richards and bring it back to New Hampshire for a proper interment. [excerpt
Packaging techniques for low-altitude Venus balloons beacon
The results of a specific design project for the Venus balloon beacon, in which a microwave beacon is required to operate for a limited time at high temperature (350 C) and at high pressure, (10 bars). In a chemically hostile environment after surviving large mechanical shock forces (up to 280 gs) are discussed. It was found that many existing, commerically-available component can be used in such a design with only minor modifications. A further result is that a crude (and consequently low-cost) test program can be designed to identify and select promising commercial components
Optical Properties of Quantum-Dot-Doped Liquid Scintillators
Semiconductor nanoparticles (quantum dots) were studied in the context of
liquid scintillator development for upcoming neutrino experiments. The unique
optical and chemical properties of quantum dots are particularly promising for
the use in neutrinoless double beta decay experiments. Liquid scintillators for
large scale neutrino detectors have to meet specific requirements which are
reviewed, highlighting the peculiarities of quantum-dot-doping. In this paper,
we report results on laboratory-scale measurements of the attenuation length
and the fluorescence properties of three commercial quantum dot samples. The
results include absorbance and emission stability measurements, improvement in
transparency due to filtering of the quantum dot samples, precipitation tests
to isolate the quantum dots from solution and energy transfer studies with
quantum dots and the fluorophore PPO.Comment: version 2, minor text update
Radiation data definitions and compilation for equipment qualification data bank
Dose definitions, physical properties, mechanical properties, electrical properties, and particle definitions are listed for insulators and dielectrics, elastomeric seals and gaskets, lubricants, adhesives, and coatings
Color Breaking Baryogenesis
We propose a scenario that generates the observed baryon asymmetry of the
Universe through a multi--step phase transition in which SU(3) color symmetry
is first broken and then restored. A spontaneous violation of
conservation leads to a contribution to the baryon asymmetry that becomes
negligible in the final phase. The baryon asymmetry is therefore produced
exclusively through the electroweak mechanism in the intermediate phase. We
illustrate this scenario with a simple model that reproduces the observed
baryon asymmetry. We discuss how future electric dipole moment and collider
searches may probe this scenario, though future EDM searches would require an
improved sensitivity of several orders of magnitude.Comment: Updated to comply with referees suggestions and mirror published
versio
TeV Lepton Number Violation: From Neutrinoless Double Beta Decay to the LHC
We analyze the sensitivity of next-generation tonne-scale neutrinoless double
-decay () experiments and searches for same-sign
di-electrons plus jets at the Large Hadron Collider to TeV scale lepton number
violating interactions. Taking into account previously unaccounted for physics
and detector backgrounds at the LHC, renormalization group evolution, and
long-range contributions to nuclear matrix elements, we find
that the reach of tonne-scale generally exceeds that of the
LHC. However, for a range of heavy particle masses near the TeV scale, the high
luminosity LHC and tonne-scale may provide complementary
probes.Comment: 5 pages, 3 figure
Stop-Catalyzed Baryogenesis Beyond the MSSM
Non-minimal supersymmetric models that predict a tree-level Higgs mass above
the Minimal Supersymmetric Standard Model (MSSM) bound are well motivated by
naturalness considerations. Indirect constraints on the stop sector parameters
of such models are significantly relaxed compared to the MSSM; in particular,
both stops can have weak-scale masses. We revisit the stop-catalyzed
electroweak baryogenesis (EWB) scenario in this context. We find that the LHC
measurements of the Higgs boson production and decay rates already rule out the
possibility of stop-catalyzed EWB. We also introduce a gauge-invariant analysis
framework that may generalize to other scenarios in which interactions outside
the gauge sector drive the electroweak phase transition.Comment: 9 pages, 3 figures. v2: Minor changes. Added appendix with the
details of the higgs couplings fit. References adde
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