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101.
The GRANIT system operates by applying an impulse of known force by means of an impact device that is attached to the tendon of the anchorage. The vibration response signals resulting from this impulse are complex in nature and require analysis to be undertaken in order to extract information from the vibrational response signatures that is relevant to the condition of the anchorage. In the system, the complicated relationship that exists between characteristics of an anchorage and its response to an impulse is identified and learned by a novel artificial intelligence network based on artificial intelligence techniques.The results presented in this paper demonstrate the potential of the GRANIT system to diagnose the integrity of ground anchorages at a site near Stone, England, by using a trained neural network capable of diagnosing the post-tension level of the anchorage. This neural network was used for the diagnosis of load in a second ground anchorage adjacent to the original anchorage used for the training of the neural network. Further tests were taken with a different anchor head configuration of the anchorage and a different relationship between the signature response of the anchorage to an applied impulse and its post-tension level was found.Problems encountered during the diagnosis of this second set of test signatures by the trained neural network are investigated with the use of a lumped parameter dynamic model. This model is able to identify the parameters in the anchorage system that affect this change in response signature. The results from the investigation lead to a new form of classification for the installed anchorages, based on their anchor head configuration.Laboratory strand anchorage tests were undertaken in order to compare with and validate the results obtained from the field tests and the lumped parameter dynamic model. 相似文献
102.
An apparatus is described for the measurement of unsteady thrust and propulsive efficiency produced by biologically inspired
oscillating hydrodynamic propulsors. Force measurement is achieved using a strain-gauge-based force transducer, augmented
with a lever to amplify or attenuate the applied force and control the measurement sensitivity and natural frequency of vibration.
The lever can be used to tune the system to a specific application and it is shown that, using the lever, the stiffness can
be made to increase more rapidly than the measurement sensitivity decreases. Efficiency is computed from measurements of the
time-averaged power imparted to the fluid. The apparatus is applied to two different propulsors, demonstrating the versatility
of the system; wake visualizations are examined, which provide insight into the physical mechanisms of efficient propulsion.
相似文献
James H. J. BuchholzEmail: Email: |
103.
Jodie N. Haigh Ya‐mi Chuang Brooke Farrugia Richard Hoogenboom Paul D. Dalton Tim R. Dargaville 《Macromolecular rapid communications》2016,37(1):93-99
A new method for fabricating hydrogels with intricate control over hierarchical 3D porosity using microfiber porogens is presented. Melt electrospinning writing of poly(ε‐caprolactone) is used to create the sacrificial template leading to hierarchical structuring consisting of pores inside the denser poly(2‐oxazoline) hydrogel mesh. This versatile approach provides new opportunities to create well‐defined multilevel control over interconnected pores with diameters in the lower micrometer range inside hydrogels with potential applications as cell scaffolds with tunable diffusion and transport of, e.g., nutrients, growth factors or therapeutics.
104.
Tessellations of that use convex polyhedral cells to fill the space can be extremely complicated, especially if they are not “facet‐to‐facet”, that is, if the facets of a cell do not necessarily coincide with the facets of that cell's neighbours. In a recent paper 15 , we have developed a theory which covers these complicated cases, at least with respect to their combinatorial topology. The theory required seven parameters, three of which suffice for facet‐to‐facet cases; the remaining four parameters are needed for the awkward adjacency concepts that arise in the general case. This current paper establishes constraints that apply to these seven parameters and so defines a permissible region within their seven‐dimensional space, a region which we discover is not bounded. Our constraints in the relatively simple facet‐to‐facet case are also new. 相似文献
105.
Given a reference random variable, we study the solution of its Stein equation and obtain universal bounds on its first and second derivatives. We then extend the analysis of Nourdin and Peccati by bounding the Fortet–Mourier and Wasserstein distances from more general random variables such as members of the Exponential and Pearson families. Using these results, we obtain non-central limit theorems, generalizing the ideas applied to their analysis of convergence to Normal random variables. We do these in both Wiener space and the more general Wiener–Poisson space. In the former space, we study conditions for convergence under several particular cases and characterize when two random variables have the same distribution. In the latter space we give sufficient conditions for a sequence of multiple (Wiener–Poisson) integrals to converge to a Normal random variable. 相似文献
106.
Nicky Rogge Richard Simper Marijn Verschelde Maximilian Hall 《European Journal of Operational Research》2015
This paper fills a noticeable gap in the current economic and penology literature by proposing new performance-enhancing policies based on an efficiency analysis of a sample of male prisons in England and Wales over the period 2009/10. In addition, we advance the empirical literature by integrating the managerialism of four strategic functions of prisons, employment and accommodation, capacity utilization, quality of life in prison and the rehabilitation and re-offending of prisoners. We find that by estimating multiple models focussing on these different areas some prisons are more efficient than other establishments. In terms of policy, it is therefore necessary to consider not just an overall performance metric for individual prisons, as currently undertaken annually by the UK Ministry of Justice, but to look into the administration and managerialism of their main functions in both a business and public policy perspective. Indeed, it is further necessary to view prisons together and not as single entities, so as to obtain a best practice frontier for the different operations that management undertakes in English and Welsh prisons. 相似文献
107.
108.
Let G be a compact Lie group. By work of Chataur and Menichi, the homology of the space of free loops in the classifying space of G is known to be the value on the circle in a homological conformal field theory. This means in particular that it admits operations parameterized by homology classes of classifying spaces of diffeomorphism groups of surfaces. Here we present a radical extension of this result, giving a new construction in which diffeomorphisms are replaced with homotopy equivalences, and surfaces with boundary are replaced with arbitrary spaces homotopy equivalent to finite graphs. The result is a novel kind of field theory which is related to both the diffeomorphism groups of surfaces and the automorphism groups of free groups with boundaries. Our work shows that the algebraic structures in string topology of classifying spaces can be brought into line with, and in fact far exceed, those available in string topology of manifolds. For simplicity, we restrict to the characteristic 2 case. The generalization to arbitrary characteristic will be addressed in a subsequent paper. 相似文献
109.
110.
M. Raffel H. Richard K. Ehrenfried B. Van der Wall C. Burley P. Beaumier K. McAlister K. Pengel 《Experiments in fluids》2004,36(1):146-156
Three-component particle image velocimetry measurements at moderate speeds and observation distances can now be accomplished on a routine basis. This article discusses the experiment performed on a 4 m-diameter model rotor in the 6-m×8-m open test section of the Large Low Speed Facility of the German–Dutch Wind Tunnels. More than half a terabyte of raw data were recorded at various positions on the advancing and retreating sides of the rotor in order to obtain detailed measurements of the trailing vortex in the frame of an international project. This paper addresses measuring techniques and possible sources of errors and presents a limited number of cases for the purpose of illustrating the solutions to numerous technical challenges relating to the acquisition and analysis of vortical flows.List of symbols
C
T
thrust coefficient (T/2
R
4)
-
M
magnification
-
r
c
radius of vortex core (mm)
-
R
rotor radius (m)
-
T
thrust (N)
-
u,v,w
velocity components in x, y and z coordinates (m/s)
- (u,v,w)wt
velocity components in wind tunnel coordinates (m/s)
-
U
max
maximum in-plane velocity component (m/s)
-
W
max
maximum out-of-plane velocity component (m/s)
-
x,y,z
particle image velocimetry (PIV) frame coordinates (m)
- (x,y,z)wt
wind tunnel coordinates (m)
- t
time delay (s)
- Z
light sheet thickness (mm)
- Z
light sheet thickness (mm)
-
rotor rotation frequency (rad/s)
-
rotor azimuth angle during recording (deg) vortex age
-
rotor shaft angle (deg)
-
x
displacement measurement error
-
advance ratio (V/R)
-
air density (kg/m3)
-
circulation (m2/s)
-
z
vorticity (s–1)
Abbreviations AFDD
Aeroflightdynamics Directorate
- BVI
blade–vortex interaction
- DLR
Deutches zentrum für Luft- und Raumfahrt
- DNW
German–Dutch Wind tunnel
- HART
HHC aeroacoustic rotor test
- LLF
large low speed facility
- NASA
National Aeronautics and Space Administration
- ONERA
Office National dEtudes e de Recherches Aerospatiales
- RANS
Reynolds-averaged Navier–Stokes
- SPR
stereo pattern recognition
- 3C-PIV
three-component particle image velocimetry 相似文献