ABSTRACT
In the COVID-19 era, the provision of health indicators seamlessly and without contact, in groups at risk such as the elderly, is crucial due to the fast spread of the disease and the need to act quickly to contain its evolution. Continuous monitoring of vital signs, such as body temperature and cardio-respiratory rates, can be vital in early detection and prediction of COVID-19, which rapidly progresses and particularly affects the elderly population in nursing homes. Conventional clinical methods used for monitoring vital signs are contact-based, require contact sensors that need to be precisely attached by a trained health professional, are less convenient for repeatable measurements, and not practical for long-term monitoring. On the other hand, contactless vital signs monitoring using radar-based techniques, or IR-thermal imaging, do not require the attachment of physical electrodes and can be of great value in health screening of patients and help health professionals in early detection of the COVID-19 in the elderly population, in the specific context of nursing houses. This work describes the design and specification of a low-cost contactless health screening system for nursing homes, and includes the design of an IoT Edge device that can be placed above the beds where patients rest, allowing the continuous acquisition of health information and its processing without any type of contact and invasiveness. © 2021 IEEE.
ABSTRACT
The freezing phenomenon has a dramatic impact on the quality of freeze-dried products. Several freezing models applied to solutions in vials have been proposed to predict the resulting product morphology and describe heat transfer mechanisms. However, there is a lack of detailed experimental observations of the freezing phenomenon in vials in the literature. Thus, the present work offers new experimental observations of the freezing phenomenon in vials by infrared (IR) thermography. IR imaging allowed each vial's whole axial temperature profile to be collected during freezing, providing significant insights into the process. Spontaneous nucleation and vacuum-induced surface freezing (VISF), as a controlled nucleation technique, are investigated. Batches having vials in direct contact with the shelf (exchanging heat mainly through conduction) as well as suspended (exchanging heat mainly through natural convection and radiation) were tested. The study used three solutions: sucrose 5%, mannitol 5%, and dextran 10%. SEM images coupled with an automated image segmentation technique were also performed to examine possible correlations between the freezing observations and the resulting pore size distributions. IR thermography was found to be a promising tool for experimentally predicting the resulting product morphology in-line.