Agriculture is the sector with the greatest water consumption, since food production is frequently based on crop irrigation. Proper irrigation management requires reliable information on plant water status, but all the plant-based methods to determine it suffer from several inconveniences, mainly caused by the necessity of destructive sampling or of alteration of the plant organ due to contact installation. The aim of this work is to test if terahertz (THz) time domain reflectance measurements made on the grapevine trunk allows contactless monitoring of plant status. The experiments were performed on a potted 14-years-old plant, using a general purpose THz emitter receiver head. Trunk THz time-domain reflection signal proved to be very sensitive to changes in plant water availability, as its pattern follows the trend of soil water content and trunk growth variations. Therefore, it could be used to contactless monitor plant water status. Apart from that, THz reflection signal was observed to respond to light conditions which, according to a specifically designed girdling experiment, was caused by changes in the phloem. This latter results opens a promising field of research for contactless monitoring of phloem activity.
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http://dx.doi.org/10.3389/fpls.2015.00404 | DOI Listing |
F S Sci
December 2024
The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, 10021, USA. Electronic address:
Vital signs such as heart rate (HR) and respiration rate (RR) are essential physiological parameters that are routinely used to monitor human health and bodily functions. They can be continuously monitored through contact or contactless measurements performed in the home or a hospital. In this study, a contactless Doppler radar W-band sensing system was used for short-range, contactless vital sign estimation.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Institute of Optoelectronics Technology, Key Laboratory of Luminescence and Optical Information, Beijing Jiaotong University, Beijing 100044, China.
This work explores the carrier recombination dynamics of AC-driven quantum dot (QD) light-emitting diodes (AC-QLEDs) and proposes their application in the field of electric field contactless detection. Different sequences of green QD (GQD)/red QD (RQD) bilayer thin films as the emission layer of AC-QLEDs were fabricated via film transfer printing to ensure the complete morphology of each layer. AC-QLEDs with the emission layer as the sequence of GQD + RQD (GR-QLEDs) show a significantly enhanced carrier recombination efficiency due to its stable energy level structure, achieving the highest peak brightness ever recorded for vertically emitting brightness of 1648.
View Article and Find Full Text PDFJ Appl Clin Med Phys
December 2024
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, West Java, Indonesia.
Purpose: The goal of this study was to assess the feasibility of a cost-effective prototype of a laser-based respiratory motion detection system utilizing a Leuze LDS for breath monitoring through calibration and volunteer tests.
Methods: This study was performed using the Anzai AZ-773 V and computerized imaging reference systems (CIRS) motion phantoms for calibration tests. The calibration of the laser-based respiratory motion detection system involved spatial accuracy testing, amplitude calibration, and temporal accuracy.
Transl Vis Sci Technol
December 2024
Department of Ophthalmology & Vision Sciences, University of Toronto, Toronto, ON, Canada.
Purpose: To demonstrate that high-seed, ultra-high-resolution spectral-domain optical coherence tomography (SD-OCT) technology can image in vivo fine morphological features in the healthy and pathological human limbus.
Methods: A compact, fiberoptic SD-OCT system was developed for imaging the human limbus. It combines ∼1.
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