1,200 research outputs found
Initial Comparison of Single Cylinder Stirling Engine Computer Model Predictions with Test Results
A Stirling engine digital computer model developed at NASA Lewis Research Center was configured to predict the performance of the GPU-3 single-cylinder rhombic drive engine. Revisions to the basic equations and assumptions are discussed. Model predictions with the early results of the Lewis Research Center GPU-3 tests are compared
Optimization of Turbine Rim Seals
Experiments are being conducted to gain an understanding of the physics of rim scale cavity ingestion in a turbine stage with the high-work, single-stage characteristics envisioned for Advanced Subsonic Transport (AST) aircraft gas turbine engines fo the early 21st century. Initial experimental measurements to be presented include time-averaged turbine rim cavity and main gas path static pressure measurements for rim seal coolant to main gas path mass flow ratios between 0 and 0.02. The ultimate objective of this work is develop improved rim seal design concepts for use in modern high-work, single sage turbines n order to minimize the use of secondary coolant flow. Toward this objective the time averaged and unsteady data to be obtained in these experiments will be used to 1) Quantify the impact of the rim cavity cooling air on the ingestion process. 2) Quantify the film cooling benefits of the rim cavity purge flow in the main gas path. 3) Quantify the impact of the cooling air on turbine efficiency. 4) Develop/evaluate both 3D CFD and analytical models of the ingestion/cooling process
Witnessing eigenstates for quantum simulation of Hamiltonian spectra
The efficient calculation of Hamiltonian spectra, a problem often intractable
on classical machines, can find application in many fields, from physics to
chemistry. Here, we introduce the concept of an "eigenstate witness" and
through it provide a new quantum approach which combines variational methods
and phase estimation to approximate eigenvalues for both ground and excited
states. This protocol is experimentally verified on a programmable silicon
quantum photonic chip, a mass-manufacturable platform, which embeds entangled
state generation, arbitrary controlled-unitary operations, and projective
measurements. Both ground and excited states are experimentally found with
fidelities >99%, and their eigenvalues are estimated with 32-bits of precision.
We also investigate and discuss the scalability of the approach and study its
performance through numerical simulations of more complex Hamiltonians. This
result shows promising progress towards quantum chemistry on quantum computers.Comment: 9 pages, 4 figures, plus Supplementary Material [New version with
minor typos corrected.
High-intensity interval exercise training before abdominal aortic aneurysm repair ( HIT-AAA): protocol for a randomised controlled feasibility trial
Introduction In patients with large abdominal aortic aneurysm (AAA), open surgical or endovascular aneurysm repair procedures are often used to minimise the risk of aneurysm-related rupture and death; however, aneurysm repair itself carries a high risk. Low cardiopulmonary fitness is associated with an increased risk of early post-operative complications and death following elective AAA repair. Therefore, fitness should be enhanced before aneurysm repair. High-intensity interval exercise training (HIT) is a potent, time-efficient strategy for enhancing cardiopulmonary fitness. Here, we describe a feasibility study for a definitive trial of a pre-operative HIT intervention to improve post-operative outcomes in patients undergoing elective AAA repair.
Methods and analysis A minimum of 50 patients awaiting elective repair of a 5.5–7.0 cm infrarenal AAA will be allocated by minimisation to HIT or usual care control in a 1:1 ratio. The patients allocated to HIT will complete three hospital-based exercise sessions per week, for 4 weeks. Each session will include 2 or 4 min of high-intensity stationary cycling followed by the same duration of easy cycling or passive recovery, repeated until a total of 16 min of high-intensity exercise is accumulated. Outcomes to be assessed before randomisation and 24–48 h before aneurysm repair include cardiopulmonary fitness, maximum AAA diameter and health-related quality of life. In the post-operative period, we will record destination (ward or critical care unit), organ-specific morbidity, mortality and the durations of critical care and hospital stay. Twelve weeks after the discharge, participants will be interviewed to reassess quality of life and determine post-discharge healthcare utilisation. The costs associated with the exercise intervention and healthcare utilisation will be calculated.
Ethics and dissemination Ethics approval was secured through Sunderland Research Ethics Committee. The findings of the trial will be disseminated through peer-reviewed journals, and national and international presentations
The SISO CSPI PDG standard for commercial off-the-shelf simulation package interoperability reference models
For many years discrete-event simulation has been used to analyze production and logistics problems in manufactur-ing and defense. Commercial-off-the-shelf Simulation Packages (CSPs), visual interactive modelling environ-ments such as Arena, Anylogic, Flexsim, Simul8, Witness, etc., support the development, experimentation and visua-lization of simulation models. There have been various attempts to create distributed simulations with these CSPs and their tools, some with the High Level Architecture (HLA). These are complex and it is quite difficult to assess how a set of models/CSP are actually interoperating. As the first in a series of standards aimed at standardizing how the HLA is used to support CSP distributed simula-tions, the Simulation Interoperability Standards Organiza-tion’s (SISO) CSP Interoperability Product Development Group (CSPI PDG) has developed and standardized a set of Interoperability Reference Models (IRM) that are in-tended to clearly identify the interoperability capabilities of CSP distributed simulations
Problem gambling: a suitable case for social work?
Problem gambling attracts little attention from health and social care agencies
in the UK. Prevalence surveys suggest that 0.6% of the population are
problem gamblers and it is suggested that for each of these individuals,
10–17 other people, including children and other family members, are
affected. Problem gambling is linked to many individual and social problems
including: depression, suicide, significant debt, bankruptcy, family conflict,
domestic violence, neglect and maltreatment of children and offending.
This makes the issue central to social work territory. Yet, the training of
social workers in the UK has consistently neglected issues of addictive
behaviour. Whilst some attention has been paid in recent years to substance
abuse issues, there has remained a silence in relation to gambling
problems. Social workers provide more help for problems relating to addictions
than other helping professions. There is good evidence that treatment,
and early intervention for gambling problems, including psycho-social and
public health approaches, can be very effective. This paper argues that
problem gambling should be moved onto the radar of the social work profession,
via inclusion on qualifying and post-qualifying training programmes
and via research and dissemination of good practice via institutions such as
the Social Care Institute for Excellence (SCIE).
Keywords: problem gambling; addictive behaviour; socia
Algorithm for J-Integral Measurements by Digital Image Correlation
The work is devoted to the testing of the algorithm for calculating J-integral based on the construction of vector fields by digital image correlation (DIC) method. A comparative analysis of J-integral values calculated using DIC and instrumental data obtained in accordance with ASTM E 1820 "Standard Test Method for Measurement of Fracture Toughness" has made. It is shown that this approach can be used for cases when the standard technique for measuring the J-integral cannot be applied, or the standard technique does not allow achieving the required accuracy for the integral determination in local areas of the loaded material
Fruit crops, 1986: a summary of research
Influence of treatments at planting on trellised apple tree performance / David C. Ferree -- Influence of growth regulators on branching of young apple trees / David C. Ferree and John C. Schmid -- Influence of growth regulators on scarf skin of Rome Beauty apples / David C. Ferree and John C. Schmid -- Influence of fungicides on scarf skin on Gallia Beauty / David C. Ferree and Michael A. Ellis -- Little relationship between root pruning and winter injury / James R. Schupp and David C. Ferree -- Performance of two apple cultivars on MS and M9 interstems on Antonovka / D. C. Ferree, R. M. McConnell, and J. C. Schmid -- Air sprayer jet deflection by travel or wind: as predicted by computer / R. D. Fox, R. D. Brazee, and D. L. Reichard -- Measuring atmospheric water vapor / R. D. Brazee and R. D. Fox -- A prototypic pollination unit made from expanded polystyrene / James E. Tew and Dewey M. Caron -- Effects of gibberellic acid (GA3) and daminozide (Alar) on growth and fruiting of Himrod grapes / G. A. Cahoon, M. L. Kaps, and S. P. Pathak -- Development of an action threshold for meadow spittlebug on strawberries / Mark A. Zajac and Franklin R. Hall -- Long-term yield of selected blackberry cultivars and selections in southern Ohio / Craig K. Chandler, Donald A. Chandler, and Greg L. Brenneman -- Electronic information transfer / R. C. Funt. -- A summary of research on synthetic pyrethroids and mites in the apple orchard ecosystem / Franklin R. Hall -- Controlling apple collar rot: effects of fungicides, soil amendments, and depth of planting / M. A. Ellis, D. C. Ferree, and L. V. Madden -- Validation of an electronic unit for predicting apple scab infection periods / M. A. Ellis, L. V. Madden, and L. L. Wilson -- Epidemiology and control of strawberry leather rot / G. G. Grove, M. A. Ellis, and L. V. Madden -- Research on cane diseases of thornless blackberry in Ohio / M. A. Ellis, G. A. Kuter, and L. L. Wilso
Systematic evaluation of an atomic clock at 2e-18 total uncertainty
The pursuit of better atomic clocks has advanced many research areas,
providing better quantum state control, new insights in quantum science,
tighter limits on fundamental constant variation, and improved tests of
relativity. The record for the best stability and accuracy is currently held by
optical lattice clocks. This work takes an important step towards realizing the
full potential of a many-particle clock with a state-of-the-art stable laser.
Our 87Sr optical lattice clock now achieves fractional stability of 2.2e-16 at
1 s. With this improved stability, we perform a new accuracy evaluation of our
clock, reducing many systematic uncertainties that limited our previous
measurements, such as those in the lattice ac Stark shift, the atoms' thermal
environment, and the atomic response to room-temperature BBR. Our combined
measurements have reduced the total uncertainty of the JILA Sr clock to 2.1e-18
in fractional frequency units.Comment: Full published versio
- …