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The organic coating of bridge steel girders is subjected to physical scratches, corrosion, and aging in natural weathering. The breakdown of the coating may cause serviceability and safety problems if left unnoticed. Conventional coating inspection is time-consuming and lacks information about the coating’s chemical integrity. A hyperspectral imaging method is proposed to detect the condition of steel coatings based on coating-responsive features in reflectance spectra. A field test was conducted on the real-world bridge, which shows obvious signs of degradation. The hyperspectral signature enables an assessment of the coating’s health and defect severity. The results indicated that the coating scratch can be effectively located in the domain of a hyperspectral image and the scratch depth can be determined by mapping a scratch depth indicator (SDI = R532 nm/R641 nm). Rust sources and products in steel girders can be identified by the unique spectral signatures in the VNIR range, and the rust stains (and thus stain areas) scattered on the coating can be pinpointed at pixel level by the chloride rust (CR) indicators >1.11 (CR = R733 nm/R841 nm). The chemical integrity of a topcoat is demonstrated by the short-wave infrared spectroscopy and the topcoat degradation can be evaluated by the decreased absorption at 8000 cm−1 and 5850 cm−1. Hyperspectral imaging enables faster and more reliable coating condition detection by the spectral features and provides an alternative for multi-object coating detection.

UAVs face some critical challenges in pervasive applications, such as navigation in GPS-denying areas, obstacle avoidance, and tradeoff between payload and flight time. The INSPIRE UTC at Missouri S&T is developing a clamping UAV, a hybrid flying and traversing robot, to make it possible that the UAV flies under a bridge girder, grabs the girder, and moves along the girder for inspection. This heavy UAV is difficult to control underneath the deck when equipped with multiple cameras. In this study, CFD modeling and simulation are conducted to understand the flight behavior and ceiling effect of the UAV under the bridge deck. First, 3D scanning and reverse engineering are used to build CFD models. Second, a series of single propeller tests are conducted to validate the process of CFD modeling and the simulation results. Third, based on the workflow and technique validated through single propeller CFD analysis, the CFD model of an entire UAV is established and analyzed to predict the behavior of the UAV and understand its interaction with upper boundaries as it approaches the bridge ceiling vertically. The CFD simulation results show that the ceiling effect of the designed clamping UAV is insignificant when the UAV approaches the standard bridge deck with enough depth. These results provide a technical reference for the design and control of the clamping UAV for bridge inspection.

As an optical molecular imaging modality, fluorescence molecular tomography (FMT) can monitor the activities of organisms in vivo at the molecular and cellular levels. However, the recovered image quality is affected by mesh voxel when the finite element method is utilized to recover the fluorescence probe. The target localization is likely to deviate from the actual target under the coarse mesh, but using the fine mesh will increase the number of unknowns, which makes the computational burden heavier and further aggravate the ill-posedness. To solve the problem, a reconstruction strategy using a non-uniform mesh for FMT is developed in this paper. The numerical experiment and physical experiment validated that the strategy is capable and effective for FMT.

A large-scale fluorescence measurement captured by non-contact fluorescence molecular tomography imaging system is utilized to reconstruct the three-dimensional distribution of fluorescent probe in small animals. However, this makes the computational burden heavier and restricts the capacity of this technique. In general, the extracting area of interest is a universal method of increasing the effectiveness of the reconstruction. Hence, this study proposed permissible region extraction strategy by means of the node with the maximum energy at each projection. Simulation experiment and physical experiment demonstrated that the presented method can provide high-graded images at a shorter time cost. Furthermore, the stability of this method deserves investigation even under quite ill-posed conditions.

Fluorescence molecular tomography (FMT) has been a promising imaging tool because it allows an accurate localizaton and quantitative analysis of the fluorophore distribution in animals. It, however, is still a challenge since its reconstruction suffers from severe ill-posedness. This paper introduces a reconstruction frame based on three-way decisions (TWD) for the inverse problem of FMT. On the first stage, a reconstruction result on the whole region is obtained by a certain reconstruction algorithm. With TWD, the recovered result has been divided into three regions: fluorescent target region, boundary region, and background region. On the second stage, the boundary region and fluorescent target region have been combined into the permissible region of the target. Then a new reconstruction on the permissible region has been carried out and a new recovered result is obtained. With TWD again, the new result has been classified into three pairwise disjoint regions. And the new fluorescent target region is the final reconstructed result. Both numerical simulation experiments and a real mouse experiment are carried out to validate the feasibility and potential of the presented reconstruction frame. The results indicate that the proposed reconstuction strategy based on TWD can provide a good performance in FMT reconstruction.

To make binary low-tension system play a vital role in improving oil displacement efficiency and foam system expand swept volume, binary low-tension system alternates with binary foam system flooding laboratory research is carried out after the polymer flooding technology. The method of airflow is used to proceed with foaming performance experiments by nitrogen gas. Surfactant CYL which foaming performance is stronger has good compatibility with alkali-free surfactant. The evaluation of the interfacial tension experiments shows that surfactant HLX has a low interfacial tension; the HLX's ability of reducing interfacial tension is less affected by CYL. It is shown through experiment that displacement recovery of binary foam system is 7.84% and binary low-tension system is 5.87% after polymer flooding, as well as the injection pattern of (0.05PV binary foam system+0.05PV N2+0.1PV binary low-tension system) alternating three times is best, which displacement recovery is 14.22% and 12.26% in natural core after polymer flooding. The injection pattern of profile control and oil displacement can attain a perfect effect after polymer flooding.

International audience; Introduction: A potential single-photon emission computed tomography imaging agent for labeling of A beta plaques of Alzheimer's disease, IMPY (2-(4'-dimethylaminophenyl)-6-iodo-imidazo[1,2-a]pyridine), would be effective in detection of prion amyloid deposits in transmissible spongiform encephalopathies (TSEs). Methods: In vitro autoradiographic studies were carried out with [I-125]IMPY on brain sections from scrapie-infected mice and age-matched controls. Competition study was performed to evaluate the prion deposit binding specificity with nonradioactive IMPY. Results: Binding of [I-125]IMPY was observed in infected brain sections, while on age-matched control brain sections, there was no or very low labeling. Prion deposit binding was confirmed by histoblots with prion protein-specific monoclonal antibody 2D6. In the presence of nonradioactive IMPY, the binding of [I-125]IMPY was significantly inhibited in all regions studied. Conclusions: These findings indicate that IMPY can detect the prion deposits in vitro in scrap ie-infected mice. Labeled with I-123, this ligand may be useful to quantitate prion deposit burdens in TSEs by in vivo imaging. (c) 2008 Elsevier Inc. All rights reserved.

International audience; A characteristic of prion diseases which affect both animals and humans is the aggregation of PrP amyloid fibrils in the brain, associated with a chronic inflammatory response dominated by microglial activation. In this study, we hypothesised that specific ligands of the 18-kDa translocator protein (TSPO) would be effective in the evaluation of microglial activation related to PrP(sc) deposits in prion disease. Chronological studies using in vitro autoradiography were carried out with [(3)H]-PK11195 and [(125)I]-IMPY on frozen cerebral sections from scrapie-infected mice and controls. Accumulation of prion deposits was confirmed by histoblot staining with prion protein-specific monoclonal antibody. Ex vivo autoradiographic studies were carried out with [(125)I]-CLINDE and [(125)I]-IMPY at the terminal stage of infection. Chronological studies using in vitro autoradiography showed that PrP(sc) deposits were co-localised with activated microglia as early as 60 days post-inoculation. Progressive levels of PrP(sc) and TSPO staining were successively observed in the hippocampus, cortex and left thalamus of infected mouse brain sections in the course of the disease and were correlated with the signals obtained by histoblot staining. Significant TSPO labelling was also observed ex vivo in the cortex, hippocampus and thalamus of scrapie-infected mice. In parallel, [(125)I]-IMPY showed labelling in the same cerebral regions but with high background staining. These findings indicate the ability of [(125)I]-IMPY and [(125)I]-CLINDE to evaluate prion deposits and microglial activation in vitro and ex vivo in scrapie-infected mice at different stages of the disease.

In inverter fed motor speed control systems, the electromagnetism interferes, which are caused by the high speed switching of the inverter, bring bad effects for measuring the current of the induction motor stator. In this paper, the complexity and specialty of measuring the stator current for the self-commutated inverter fed motor are studied, some experiments are carried out. As results, effective ways to reduce the interfere of the measuring circuit are provided; the on-line fault diagnosis for the induction motor broken rotor bars which run under different situations are realized, by employment of fast Fourier transform (FFT) and time-varying frequency spectrum analysis.

Based on the theory of strong tracking filters, an online fault diagnosis method for transformer is given by combining state estimation and parameter identification. Computer simulations show that this method can effectively determine what kind of fault happens and which parameter is related to the fault. In addition, the parameter identification remains accurate when the fault happens.