594 research outputs found

    Integrating the First Person View and the Third Person View Using a Connected VR-MR System for Pilot Training

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    Virtual reality (VR)-based flight simulator provides pilots the enhanced reality from the first-person view. Mixed reality (MR) technology generates effective 3D graphics. The users who wear the MR headset can walk around the 3D graphics to see all its 360 degrees of vertical and horizontal aspects maintaining the consciousness of real space. A VR flight simulator and an MR application were connected to create the capability of both first-person view and third-person view for a comprehensive pilot training system. This system provided users the capability to monitor the aircraft progress along the planned path from the third-person view as well as how the aircraft pilot follows the desired flight procedures in the cockpit from the first-person view. Six flight instructors provided their feedback after trying the prototype functions. The three flight instructors with more than 1,000 flight hours gave negative feedback whereas the three instructors with less than 1,000 flight hours were more open to the technologies. The effectiveness of MR-based real-time monitoring and post-debriefing system is yet to be clear. However, the test results included the potentials of the prototype for future improvement based on MR technology’s flexibility

    Truck-based mobile wireless sensor networks for the experimental observation of vehicle–bridge interaction

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    Heavy vehicles driving over a bridge create a complex dynamic phenomenon known as vehicle–bridge interaction. In recent years, interest in vehicle–bridge interaction has grown because a deeper understanding of the phenomena can lead to improvements in bridge design methods while enhancing the accuracy of structural health monitoring techniques. The mobility of wireless sensors can be leveraged to directly monitor the dynamic coupling between the moving vehicle and the bridge. In this study, a mobile wireless sensor network is proposed for installation on a heavy truck to capture the vertical acceleration, horizontal acceleration and gyroscopic pitching of the truck as it crosses a bridge. The vehicle-based wireless monitoring system is designed to interact with a static, permanent wireless monitoring system installed on the bridge. Specifically, the mobile wireless sensors time-synchronize with the bridge's wireless sensors before transferring the vehicle response data. Vertical acceleration and gyroscopic pitching measurements of the vehicle are combined with bridge accelerations to create a time-synchronized vehicle–bridge response dataset. In addition to observing the vehicle vibrations, Kalman filtering is adopted to accurately track the vehicle position using the measured horizontal acceleration of the vehicle and positioning information derived from piezoelectric strip sensors installed on the bridge deck as part of the bridge monitoring system. Using the Geumdang Bridge (Korea), extensive field testing of the proposed vehicle–bridge wireless monitoring system is conducted. Experimental results verify the reliability of the wireless system and the accuracy of the vehicle positioning algorithm.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90810/1/0964-1726_20_6_065009.pd

    Changes of phenolic compounds in LebZIP2-overexpressing transgenic plants

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    484-491The bZIP gene is a transcription factor that plays various roles in relation to plant stress and hormone signaling. This gene is also involved in plant environmental stress and herbicide tolerance. We generated Nicotiana benthamiana transgenic plants with LebZIP2-encoding gene isolated from tomatoes using Agrobacterium-mediated transformation. Transgenic seeds harvested from these T0 transgenic plants were grown and examined for gene transfer and changes in phenolic compounds in the T1 generation. RT-PCR analysis using a primer specific to the LebZIP gene confirmed that the gene was transferred to the T1 generation. We analyzed the increase and decrease tendency for 30 phenolic compounds using the T1 generation-transgenic plants and investigated the mechanism between the specifically increased compound and LebZIP2 gene. Gallic acid, homogentisic acid, protocatechuic acid, myricetin, t-cinnamic acid, and b-resorcyclic acid were identified as the phenolic compounds that increased in T1 transgenic plants overexpressing the LebZIP gene. Among these, homogentisic acid at 246.75-1055.19 ”g/g, was increased by 2-5 fold in the T1 transgenic plants compared to the control. Protocatechuic acid was found at 1640.54-2456.00 ”g/g and was increased by 2-4 fold in T1 transgenic plants. t-Cinnamic acid was present in a small amount of 23.14 ”g/g in the control, whereas it was 102.19-135.47 ”g/g in T1 transgenic plants, showing an increase of 4-5 folds. These results indicated that homogentisic acid, protocatechuic acid, and t-cinnamic acid among the 30 phenolic compounds analyzed, were significantly increased in LebZIP2-overexpressing T1 transgenic plants, and support the evidence that the LebZIP2 gene is significantly involved in the increment of three phenolic compounds

    Long distance fiber Bragg grating strain sensor interrogation using a high speed Raman-based Fourier domain mode-locked fiber laser with recycled residual Raman pump

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    We propose a novel fiber Bragg grating (FBG) sensor interrogation using a Raman-based Fourier-domain mode locking (FDML) fiber laser for a high speed and long distance measurement. A residual Raman pump after the generation of the Raman-based FDML fiber laser is recycled for secondary signal amplification in a 2-m erbium-doped fiber (EDF) to further enhance the output power. The chromatic dispersion is precisely controlled to suppress the phase noise in the FDML laser cavity, resulting in the improvement of an R-number of 1.43 mm/dB. After recycling residual pump, we achieve the 40-km round trip transmission of the sensing probe signal with a high scan rate of 30.8 kHz. With 205-mW residual pump power, the bandwidth and the maximum gain are measured to be more than 50 nm, 10.3 dB at 1550 nm, respectively. The sensitivity of the proposed Raman-based FDML fiber laser to strain is also measured, which are 0.81 pm/ÎŒstrain in the spectral domain and 0.19 ns/ÎŒstrain in the time domain, respectively

    Linear Magnetoelectric Phase in Ultrathin MnPS₃ Probed by Optical Second Harmonic Generation

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    The transition metal thiophosphates MPS₃ (M=Mn, Fe, Ni) are a class of van der Waals stacked insulating antiferromagnets that can be exfoliated down to the ultrathin limit. MnPS₃ is particularly interesting because its NĂ©el ordered state breaks both spatial-inversion and time-reversal symmetries, allowing for a linear magnetoelectric phase that is rare among van der Waals materials. However, it is unknown whether this unique magnetic structure of bulk MnPS₃ remains stable in the ultrathin limit. Using optical second harmonic generation rotational anisotropy, we show that long-range linear magnetoelectric type NĂ©el order in MnPS₃ persists down to at least 5.3 nm thickness. However an unusual mirror symmetry breaking develops in ultrathin samples on SiO₂ substrates that is absent in bulk materials, which is likely related to substrate induced strain
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