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International audience; The transverse relaxation time (T2), measured with Carr-Purcell-Meiboom-Gill (CPMG) sequence, has been widely used to obtain the direct dimension data in two-dimension time domain NMR (2D TD-NMR). In this paper we are demonstrating that Continuous Wave Free Precession sequence, with low flip angle (CWFP-T1), can be an alternative to CPMG as direct detection dimension. CWFP-T1 is a fast single shot sequence, like CPMG, and yields an exponential signal governed predominantly by the longitudinal (T1) relaxation time. To obtain the correlations between T1 and T2 (T1-T2 maps) we are proposing the use of CPMG-CWFP-T1 pulse sequence. In this sequence CPMG encodes T2 information (indirect dimension) that modulates the CWFP-T1 (direct dimension) signal amplitudes. CPMG-CWFP-T1 experiments were compared with classical 2D sequences such as Saturation-Recovery-CPMG (SR-CPMG) and Inversion-Recovery-CPMG (IR-CPMG) sequence and yields similar results in phantom sample. The experimental time for the 2D sequences, using single scan, shows that SR-CPMG ' CPMG-CWFP-T1 < IR-CPMG. Experimental and simulated results demonstrated that 2D-CPMG-CWFP-T1 maps have higher resolution in T1 dimension than the techniques that uses CPMG as direct dimension. CPMG-CWFP-T1 sequence was also applied to study beef samples, and 2D maps showed higher resolution in the two fat signals than the classical IR-CPMG method. © 2019 Elsevier Inc.

The LHC upgrade is planned to enhance the instantaneous luminosity during Run 3 from 2021 through 2023. The Phase-I upgrade of the trigger readout electronics for the ATLAS Liquid Argon (LAr) Calorimeters will be installed during the second long shutdown of LHC in 2019-2020. In this upgrade, the so-called super cells are introduced to provide higher granularity, higher resolution and longitudinal shower shape information from the LAr calorimeters to the level-1 trigger processors. A new LAr Trigger Digitizer Board (LTDB) will manipulate and digitize 320 channels of super cell signals, and transmit it via 40 fiber optical links to the back end where data are further processed and transmitted to the trigger processors. Five pairs of bidirectional GBT links are used for slow control from the Front-end LInks eXchange (FELIX) in the ATLAS TDAQ system. LTDB also outputs 64 summed analog signals to the current Tower Builder Board via the new baseplane. A test system is developed to test all functions of the LTDB and carry out the performance measurement. A back end PCIe card is designed which has the circuit to interface to the ATLAS trigger, time and control system. It can control the generation of injection signals to the LTDB for performance test. It also configures and calibrate all ASICs on the LTDB., This manuscript for conference record of the 21st IEEE Real Time conference

Increasing requirements concerning the quality and lifetime of machine components in industrial and automotive applications require comprehensive investigations of the components in conditions close to the application. Irregularities in heating of mechanical parts reveal regions with increased loading of pressure, draft or friction. In the long run this leads to damage and total failure of the machine. Thermographic measurements of rotating objects, e.g., rolling bearings, brakes, and clutches provide an approach to investigate those defects. However, it is challenging to measure fast-rotating objects accurately. Currently one contact-free approach is performing stroboscopic measurements using an infrared sensor. The data acquisition is triggered so that the image is taken once per revolution. This leads to a huge loss of information on the majority of the movement and to motion blur. The objective of this research is showing the potential of using an optomechanical image derotator together with a thermographic camera. The derotator follows the rotation of the measurement object so that quasi-stationary thermal images during motion can be acquired by the infrared sensor. Unlike conventional derotators which use a glass prism to achieve this effect, the derotator within this work is equipped with a sophisticated reflector assembly. These reflectors are made of aluminum to transfer infrared radiation emitted by the rotating object. Because of the resulting stationary thermal image, the operation can be monitored continuously even for fast-rotating objects. The field of view can also be set to a small off-axis region of interest which then can be investigated with higher resolution or frame rate. To depict the potential of this approach, thermographic measurements on a rolling bearings in different operating states are presented. © 2017 SPIE.

Miniaturized machine tools have been established as a promising technology for machining the miniature components in wider range of materials. Spindle of a miniaturized machine tool needs to provide extremely high rotational speed, while maintaining the accuracy. In this work, a capacitive sensor-based measurement technique is followed for assessing radial errors of a miniaturized machine tool spindle. Accuracy of spindle error measurement is affected by inherent error sources such as sensor offset, thermal drift of spindle, centering error, and form error of the target surface installed in the spindle. In the present work, a model-based curve-fitting method is proposed for accurate interpretation and analysis of spindle error measurement data in time domain. Experimental results of the proposed method are presented and compared with the commonly followed discrete Fourier transform-based frequency domain-filtering method. Proposed method provides higher resolution for the estimation of fundamental frequency of spindle error data. Synchronous and asynchronous radial error values are evaluated in accordance with ANSI/ASME B89.3.4M [9] standard at various spindle speeds and number of spindle revolutions. It is found that the spindle speed and number of spindle revolutions does not have much influence on synchronous radial error of the spindle. On the other hand, asynchronous radial error motion exhibits a significant speed-dependant behavior with respect to the number of spindle revolutions. � Springer-Verlag London Limited 2011.

We investigate the ideal and incompressible magnetohydrodynamic (MHD) equations in three space dimensions for the development of potentially singular structures. The methodology consists in implementing the fourfold symmetries of the Taylor-Green vortex generalized to MHD, leading to substantial computer time and memory savings at a given resolution; we also use a regridding method that allows for lower-resolution runs at early times, with no loss of spectral accuracy. One magnetic configuration is examined at an equivalent resolution of 6144 3 points and three different configurations on grids of 4096 3 points. At the highest resolution, two different current and vorticity sheet systems are found to collide, producing two successive accelerations in the development of small scales. At the latest time, a convergence of magnetic field lines to the location of maximum current is probably leading locally to a strong bending and directional variability of such lines. A novel analytical method, based on sharp analysis inequalities, is used to assess the validity of the finite-time singularity scenario. This method allows one to rule out spurious singularities by evaluating the rate at which the logarithmic decrement of the analyticity-strip method goes to zero. The result is that the finite-time singularity scenario cannot be ruled out, and the singularity time could be somewhere between t = 2.33 and t = 2.70 . More robust conclusions will require higher resolution runs and grid-point interpolation measurements of maximum current and vorticity. Fil: Brachet, M. E.. Centre National de la Recherche Scientifique. Ecole Normale Superieur; Francia Fil: Bustamante, M. D.. University College Dublin; Irlanda Fil: Krstulovic, G.. Observatoire de la Cote D; Francia Fil: Mininni, Pablo Daniel. National Center for Atmospheric Research; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Pouquet, A.. National Center for Atmospheric Research; Estados Unidos Fil: Rosenberg, D.. National Center for Atmospheric Research; Estados Unidos

In vivo imaging technologies drive the development of improved cancer therapies by revealing critical aspects of the complex pathophysiology of solid tumors in small animal models[1]. The abnormal vascular function, which predicts tumor malignant potential and presents broad barriers to effective treatment, has been studied at the subcellular size scale using multiphoton (MP) microscopy [2], and at significantly larger size scales using ultrasound, μCT and μMRI[3-5]. However, limited in vivo imaging approaches exist to study the vascular function at the network level, i.e., with sufficient resolution to discern smaller vessels while maintaining a field of view and penetration depth large enough to reveal interconnectivity and inhomogeneities across the tumor and surrounding tissue. One promising technology operating at this size scale is optical frequency domain imaging (OFDI) using Doppler-methods to detect blood flow. We have recently designed and constructed a Doppler OFDI system specifically for the application of vascular imaging in tumor models[6]. The technical aspects of this system that enable the required levels of flow sensitivity and imaging speed are described. Beam scanning patterns used for this system will be reviewed and analyzed. The construction of the imaging system including high-rate data acquisition with the ability to continuously stream data at rates of 400 MB/sec will be described. Finally, the algorithms used to process, filter, and display the acquired volumetric datasets as vascular projections will be described. To validate the developed Doppler OFDI instrument for this application, its capabilities and limitations were explored relative to those of multiphoton microscopy, the standard optical imaging approach applied to the study of tumor biology. We investigated both the resolution and penetration depth, as well as differences in vascular visibility resulting from the differing mechanisms of contrast (endogenous flow in Doppler OFDI, exogenous fluorescent agent in multiphoton microscopy). Figure 1 illustrates a comparison between Doppler and MP in vivo imaging of a region of normal brain in a mouse cranial window model. Semi-automated vessel tracing algorithms were applied to each dataset, allowing quantitative comparison of visualized vessel sizes. As expected, multiphoton microscopy provides higher resolution, but, as indicated in Fig. 1(e), each modality provides consistent sizing of vessels exceeding 10 microns in diameter. To compare the ability of each modality to image the abnormal vessels within and surrounding tumors, we performed imaging with each modality in a series of tumors in a dorsal skin chamber models. ©2010 IEEE. 59 60 59-60

Limited experimental resolution is a unavoidable feature in macromolecular crystallography: it may hinder or make difficult the determination of the crystal structure. A novel procedure is presented which from an approximate electron-density map extrapolates the moduli and phases of non-measured reflections beyond and behind the experimental resolution limit. Applications to a set of test structures show that the extrapolation can be successfully accomplished. As a consequence, the phase estimates of the observed reflections are subsequently improved and the interpretability of the corresponding electron-density map increases. The use of the extrapolated values for the non-measured reflections provides additional information for the map, which shows a resolution higher than the experimental resolution.

A unified model framework with online-coupled meteorology and chemistry and consistent model treatments across spatial scales is required to realistically simulate chemistry-aerosol-cloud-radiation-precipitation-climate interactions. In this work, a global-through-urban WRF/Chem model (i.e., GU-WRF/Chem) has been developed to provide such a unified model framework to simulate these important interactions across a wide range of spatial scales while reducing uncertainties from the use of offline-coupled model systems with inconsistent model treatments. Evaluation against available observations shows that GU-WRF/Chem is capable of reproducing observations with comparable or superior fidelity than existing mesoscale models. The net effect of atmospheric aerosols is to decrease shortwave and longwave radiation, NO2 photolysis rate, near-surface temperature, wind speed at 10-m, planetary boundary layer height, and precipitation as well as to increase relative humidity at 2-m, aerosol optical depths, column cloud condensation nuclei, cloud optical thickness, and cloud droplet number concentrations at all scales. As expected, such feedbacks also change the abundance and lifetimes of chemical species through changing radiation, atmospheric stability, and the rates of many meteorologically- dependent chemical and microphysical processes. The use of higher resolutions in progressively nested domains from the global to local scale notably improves the model performance of some model predictions (especially for chemical predictions) and also captures spatial variability of aerosol feedbacks that cannot be simulated at a coarser grid resolution. Simulated aerosol, radiation, and cloud properties exhibit small-to-high sensitivity to various nucleation and aerosol activation parameterizations. Representing one of the few unified global-through-urban models, GU-WRF/Chem can be applied to simulate air quality and its interactions with meteorology and climate and to quantify the impact of global change on urban/regional air quality across various spatial scales. © 2012. American Geophysical Union. All Rights Reserved.