Development and modification of National Instruments Data Acquisition hardware for use in the centrifuge environment

This paper details the modification of a commercial data acquisition system for use in a geotech-nical centrifuge. As with many ‘off-the-shelf’ components put into service within the harsh high stress centri-fuge environment, they are not originally conceived to operate under these extreme conditions and thus it is not uncommon for high failure rates to occur in standard hardware items. In many cases successful modification can be implemented to strengthen standard components to enhance their robustness and operation. In this re-spect, this paper reports on difficulties experienced in the operation of a National Instruments PXI chassis sys-tem and its failure in the high gravity environment. Specific problems identified relate to fragility of the cooling fan systems that generate fault conditions that trigger auto shut down sequence of the chassis. A bespoke solution is developed and documented that has been successfully implemented to circumnavigate and mitigate fan failures

An Additive Basis for the Chow Ring of M₀,₂(Pr,2)

We begin a study of the intersection theory of the moduli spaces of degree two stable maps from two-pointed rational curves to arbitrary-dimensional projective space. First we compute the Betti numbers of these spaces using Serre polynomial and equivariant Serre polynomial methods developed by E. Getzler and R. Pandharipande. Then, via the excision sequence, we compute an additive basis for their Chow rings in terms of Chow rings of nonlinear Grassmannians, which have been described by Pandharipande. The ring structure of one of these Chow rings is addressed in a sequel to this paper

Centrifuge Health Monitoring of the 50gTon beam centrifuge at the University of Sheffield

In order to fully understand scientific test data it is crucial that we first understand the back-ground centrifuge operational environment and its variation with time and centrifugal acceleration. For exam-ple, changes in ambient air temperature or relative humidity in the centrifuge chamber during operation can have a significant impact on the evaporation levels of water from the surface of a clay model. It is vital to un-derstand these temporal changes in order to mitigate drying out of the soil surface as this would have a detrimental impact on model performance. This paper details the development of a centrifuge health monitoring system capable of measuring environmental parameters over natural seasonal variations of the laboratory environment but also during test conditions. The results of a series of preliminary tests of different duration, acceleration and configuration are discussed to demonstrate the significant changes that occur in the scientific environment during operation

Development of a 25ton consolidation press at the Centre for Energy and Infrastructure Ground Research

1d consolidation frame has been designed and manufactured at the Centre for Energy and Infrastructure Ground Research (CEIGR), University of Sheffield. The consolidation frame allows static consolidation of soil beds. This system comprises of a 25 ton rated press that can accommodate a range of centrifuge payload strong box configurations. The consolidation force is delivered via a hydraulic piston rated to deliver 80 kN force at 10bar supply pressure with a stroke of 500mm. A series of vertical draw-wire transducers are implemented which monitor consolidation settlement. Combined with pore pressure transducers, the user can measure the pore water pressure at the top and at the bottom of the clay sample. A bespoke LabVIEW VI visual display is implemented which offers visual/graphical feedback to the user on the range of sensor information and a live update of consolidation progress; it also incorporates data entry to capture test specific in-formation

FPTAS for optimizing polynomials over the mixed-integer points of polytopes in fixed dimension

We show the existence of a fully polynomial-time approximation scheme (FPTAS) for the problem of maximizing a non-negative polynomial over mixed-integer sets in convex polytopes, when the number of variables is fixed. Moreover, using a weaker notion of approximation, we show the existence of a fully polynomial-time approximation scheme for the problem of maximizing or minimizing an arbitrary polynomial over mixed-integer sets in convex polytopes, when the number of variables is fixed.Comment: 16 pages, 4 figures; to appear in Mathematical Programmin

An intravaginal ring for real-time evaluation of adherence to therapy

© 2017 Moss et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Two recent Phase III clinical trials to investigate an intravaginal ring for preventing HIV infection demonstrated that adherence to prescribed device use was a primary driver of efficacy. Surrogate methods for determining adherence in the studies were limited in their inability to monitor temporal patterns of use and allow deconvolution of the effects of adherence and device efficacy on HIV infection rates. To address this issue, we have developed functionality in an intravaginal ring to continuously monitor when the device is being used and maintain a log of adherence that can be accessed by clinicians after it is removed. An electronic module fabricated with common, inexpensive electronic components was encapsulated in a silicone intravaginal ring. The device uses temperature as a surrogate measure of periods of device insertion and removal, and stores a record of the data for subsequent retrieval. The adherence-monitoring intravaginal ring accurately recorded the device status over 33 simulated IN-OUT cycles and more than 1000 measurement cycles in vitro. Following initial in vitro testing in a temperature-controlled chamber, the device was evaluated in vivo in sheep using a predetermined insertion/removal pattern to simulate intravaginal ring use. After insertion into the vaginal cavity of a sheep, the logged data correctly indicated the device status over 29 hours of continuous measurement including three cycles of insertion and removal. The device described here is a promising, low-cost method for real-time adherence assessment in clinical trials involving medicated intravaginal rings or other intravaginal devices

Information-Based Physics: An Observer-Centric Foundation

It is generally believed that physical laws, reflecting an inherent order in the universe, are ordained by nature. However, in modern physics the observer plays a central role raising questions about how an observer-centric physics can result in laws apparently worthy of a universal nature-centric physics. Over the last decade, we have found that the consistent apt quantification of algebraic and order-theoretic structures results in calculi that possess constraint equations taking the form of what are often considered to be physical laws. I review recent derivations of the formal relations among relevant variables central to special relativity, probability theory and quantum mechanics in this context by considering a problem where two observers form consistent descriptions of and make optimal inferences about a free particle that simply influences them. I show that this approach to describing such a particle based only on available information leads to the mathematics of relativistic quantum mechanics as well as a description of a free particle that reproduces many of the basic properties of a fermion. The result is an approach to foundational physics where laws derive from both consistent descriptions and optimal information-based inferences made by embedded observers.Comment: To be published in Contemporary Physics. The manuscript consists of 43 pages and 9 Figure

WS9.3 Reduced physical activity participation is associated with increased need for hospitalisation in adults with cystic fibrosis

n/

Direct and indirect scaling of membership functions of probability phrases

A crucial issue in the empirical measurement of membership functions is whether the degree of fuzziness is invariant under different scaling procedures. In this paper a direct and an indirect procedure, magnitude estimation and graded pair-comparison, are compared in the context of establishing membership functions for probability phrases such as , and so forth. Analyses at the level of individual respondents indicate that: (a) membership functions are stable over time; (b) functions for each phrase differ substantially over people; (c) the two procedures yield similarly shaped functions for a given person-phrase combination; (d) the functions from the two procedures differ systematically, in that those obtained directly dominate, or indicate greater fuzziness than do those obtained indirectly; and (e) where the two differ the indirectly obtained function may be the more accurate one. A secondary purpose of the paper is to evaluate the effects of the modifiers and . has a general intensifying effect that is described by Zadeh's concentration model for 7 subjects and by a shift model for no one. The effects of are unsystematic and not described by any available model

Using solar oscillations to constrain the equation of state and low-temperature opacities

Because thousands of solar P-mode oscillation frequencies have been measured to high accuracy, direct comparisons between calculated and observed frequencies are an excellent means of testing solar interior physics. Here we compare observed and calculated nonadiabatic frequencies of solar models that include diffusive settling of helium and heavier elements. We consider the effects of low-temperature opacities, equation of state, and a nonequilibrium radiation diffusion treatment on solar structure and oscillations