Reconstructing Time

The timing of events in a disaster is critical in determining the cause of the accident. Nagy explains that the order and time in which the events OC curred is important to get a proper perspective on the actitms.  

But miners disagreed about the precise time of events as they perceived them at different locations. Salisbury claimed he made a phone call to the surface at 9 10 PM. Two miners underground (Bloomquist and Nelson) and two on the surface (L. Cox and Leavitt) corroborated his testimony but dis-agreed about the precise time of the phone call. 

Since no one noted the precise time of these events during the disaster, Nagy explains that he achieved a reasonable correlation of events by assigning reasonable reconstructed times for events such as the stopping of the belt or the first phone call to Mounteer  

Source Nagy (1985) Wilberg Investigation, Appendix H, Table 2, pp. 9-10. 

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Figure 10 Reconstructed time-dependent emission spectra of WS2 nanoparticles in octane. The times (in picoseconds) corresponding to each spectrum are also given. (From Ref. 68.)...

Fig. 2 (a) Fluorescence up-conversion transients of TAB dissolved in n-heptane. Detection wavelengths in nm are indicated in circles (b) reconstructed time-resolved fluorescence spectra of TAB in n-heptane... 

Emission decays were obtained from a fs Tl sapphire laser uorescence upconversion spectrometer whose construction is reported elsewhere [8]. Here we only note that the overall temporal response used in these studies was between 112-125 fs as measured by the FWHM of the cross correlation between the pump and gate pulses. Decays (0-200 ps with a variable step size) were collected at a series of ten emission wavelengths (8 nm bandpass) which were then used to reconstruct time-evolving emission spectra in the manner described in Refs. 8 and 9. From these spectra the solvation dynamics was extracted in the form of the spectral response function,... 

Figure 2. Reconstructed time-resolved fluorescence spectra of Cl02 in (a) DMA and (b) AN. TTte dots are the dam experimentally obtained, and the curves are the log-normal fits to the dots.

Fig. 5. Reconstructed time-temperature curves for the Brent Group in the Oseberg field, and timing of oil emplacement. After Dahl Yiikler (1991) and Walderhaug (1994).

The final step is tomographic reconstruction, presently done using filtered backprojection using the IDL Riemann function. Reconstruction times are a few hours for a 512x512x512 3-D data set using a single 450 MHz Pentium PC running Windows NT. Visualization is currently performed in IDL on the local PC at the beamline. 

Figure4.16 Reconstructed time-resolved emission spectra ofJSC...

Section display allows visualization of multiple sections of the acquired volume scan along three orthogonal planes acquisition plane, transverse or sagittal reconstructed plane, and C-plane (parallel to the transducer surface). Computer-user interface tools allow the operator to rotate and reposition these planes so that the entire volume of data can be examined. Because this technique is easy to implement and allows short 3D reconstruction times, it has been largely used in clinical applications (Hamper et al. 1994). 

Wintersperger BJ, Nikolaou K, von Ziegler F et al. (2006) Image quality, motion artifacts, and reconstruction timing of 64-slice coronary computed tomography angiography with 0.33-second rotation speed. Invest Radiol 41 436 442... 

In the transvenous approach for treatment of direct carotid-cavernous sinus fistulae, unintentional coil prolapse in the supplying artery is a feared compfication, which may result in emboHc stroke. Due to dramatically reduced reconstruction times down to less than 1 min, FD-CT can be quickly performed and thus might be very helpful in the assessment of coil protrusions in the parent artery, otherwise not visible in 2D projections (Fig. 40.11). 

Figure 6.12 A fixed mouse lung was scanned with ditferent scan protocols and reconstructions were calculated at the same position. Different scan resolutions, related reconstruction times, and the required memory per slice (for half field of view reconstruction) are shown (a) 35 p,m/voxel, 500 x 500 x 16 hit matrix, 0.5 MB/sUce, 30 min volume acquisition time, 1 min hack projection time per slice, (b) 18 p,m/voxel, 1000 x 1000 X 16 hit matrix, 2 MB/slice, 90 min volume acquisition time, 2 min back projection time/slice. (c) 9 p,m/voxel, 2000 x 2000 x 16 bit matrix, 8MB/sUce, 270 min volume acquisition time, 7 min back projection time/slice.

Fig. 10. Water tower scan at the campus of UC Davis, (a) Raw point cloud having 4.3 mio. points, (b) reconstruction having 300k faces (10 subdivision steps) (total reconstruction time of about 23 seconds performed with an Intel Core2 Duo).

Reconstructed Time Reported Time Person Reference Event... 

Both the reported times and the reconstructed times are highly uncertain. To reconcile differences, Nagy must evaluate the rhetorical distance between the observers locations and the events they describe. 

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