64,588 research outputs found
A monostrain test apparatus
Test apparatus is designed for determining tensile strength, modulus of elasticity, elongation, and thermal coefficient of contraction or expansion of uniformly shaped plastics, adhesives, and foam materials over temperature range of 700 to 90 K (800 to -300). Tests may be used in design quality control, and in evaluation of new adhesives and plastic materials
Evaluation of high temperature structural adhesives for extended service
The preliminary evaluation of crosslinked polyphenyl quinoxaline (X-PPQ), LARC-TPI, ethyl terminated polysulfone (ETPS), and crosslinked polyimide (X-PI) as adhesives is presented. Lap shear strength stability under thermal, combined thermal/humidity, and stressed and unstressed Skydrol exposure was determined. The X-PPQ, LARC-TPI, and X-PI exhibited good adhesive performance at 505K (450 F) after 1000 hours at 505K. These three polymers also performed well after exposure to combined elevated temperature/high humidity, as well as, to Skydrol while under stress. The ETPS exhibited good ambient temperature adhesive properties, but performed poorly under all other exposure conditions, presumably due to inadequate chain extension and crosslinking
Sensing of Fluctuating Nanoscale Magnetic Fields Using NV Centres in Diamond
New magnetometry techniques based on Nitrogen-Vacancy (NV) defects in diamond
allow for the imaging of static (DC) and oscillatory (AC) nanoscopic magnetic
systems. However, these techniques require accurate knowledge and control of
the sample dynamics, and are thus limited in their ability to image fields
arising from rapidly fluctuating (FC) environments. We show here that FC fields
place restrictions on the DC field sensitivity of an NV qubit magnetometer, and
that by probing the dephasing rate of the qubit in a magnetic FC environment,
we are able to measure fluctuation rates and RMS field strengths that would be
otherwise inaccessible with the use of DC and AC magnetometry techniques. FC
sensitivities are shown to be comparable to those of AC fields, whilst
requiring no additional experimental overheads or control over the sample.Comment: 5 pages, 4 figure
Adhesive for aluminum withstands cryogenic temperatures
Polyurethane adhesive mixed to various proportions with milled glass fibers match the thermal characteristics of 2014-T6 aluminum at cryogenic temperatures
On Superalgebras of Matrices with Symmetry Properties
It is known that semi-magic square matrices form a 2-graded algebra or
superalgebra with the even and odd subspaces under centre-point reflection
symmetry as the two components. We show that other symmetries which have been
studied for square matrices give rise to similar superalgebra structures,
pointing to novel symmetry types in their complementary parts. In particular,
this provides a unifying framework for the composite `most perfect square'
symmetry and the related class of `reversible squares'; moreover, the
semi-magic square algebra is identified as part of a 2-gradation of the general
square matrix algebra. We derive explicit representation formulae for matrices
of all symmetry types considered, which can be used to construct all such
matrices.Comment: 25 page
Optimising Matrix Product State Simulations of Shor's Algorithm
We detail techniques to optimise high-level classical simulations of Shor's
quantum factoring algorithm. Chief among these is to examine the entangling
properties of the circuit and to effectively map it across the one-dimensional
structure of a matrix product state. Compared to previous approaches whose
space requirements depend on , the solution to the underlying order-finding
problem of Shor's algorithm, our approach depends on its factors. We performed
a matrix product state simulation of a 60-qubit instance of Shor's algorithm
that would otherwise be infeasible to complete without an optimised
entanglement mapping.Comment: 8 pages, 2 figures, 2 tables. v2 using PDFLaTeX compiler. v3 to
include extra references. v4 for publication in Quantu
School Food Environments and Policies in U.S. Public Schools
Examines food environments in elementary, middle, and high schools based on seventeen factors, including foods and beverages offered, the availability of vending machines, and how they vary by grade level, location, and other school characteristics
Introduction to 'Growing Bougainville’s Future'
Introduction to the edited collection "Growing Bougainville's Future: Choices for an Island and its Peoples" which addresses the choices faced by the peoples of Bougainville in relation to the reopening of the Panguna mine against the backdrop of the Island's pending indeÂpendence referendum. The mine, which was one of the largest copper-gold mines in the world and acted as one of the triggers for Bougainville's civil war, and continues to be central to debates about Bougainville’s economic and political future
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