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The technical specifications and the evaluation of the remote operation of the open-path, tunable diode laser absorption spectroscopic (TDLAS) instrument are presented. The instrument is equipped with two low optical power diode lasers in the near-infrared spectral range for the atmospheric detection of carbon dioxide, methane, and water vapors (CO2, CH4, and H2O). Additionally, the instrument eliminates the requirement of retroreflectors since it detects the back reflection of the laser beam from any topographic target. The instrument was operated remotely by measuring background concentrations of CO2 and CH4 in the atmosphere from 24 November 2022 to 4 January 2023. The accuracy of CO2 and CH4 measurement retrievals on a 200 m laser path was estimated at 20 ppm (4.8%) and 60 ppb (3.1%), respectively. The CH4 accuracy is comparable, but the CO2 accuracy is noticeably lower than the accuracy achieved in local operation. The accuracy issues raised are studied and discussed in terms of the laser driver's cooling performance. [ABSTRACT FROM AUTHOR]

In this paper, we identify key challenges faced by computer-based assessment (CBA) in secondary education and we put forward a framework of design considerations: design with the students and teachers, select the most appropriate media platform and plan an evolution rather than a revolution of prior practices. We present the CBA application "MyTest" which was developed using the participatory methodology We!Design, with the collaboration of 31 students and teachers. The application is targeted for the Tablet PC platform, provides "digital ink" capabilities and supports both closed-type and open questions, facilitating the transfer of traditional assessment practices to CBA. Both students and teachers were excited about the design sessions, and they asserted that they would rely more on educational software designed using this approach. The comparison of the "MyTest" application with an assessment application developed with the same participatory methodology and the involvement of 40 undergraduate students revealed dissimilar expectations and needs of high school and undergraduate students that are often disguised or misinterpreted. A pilot evaluation of the application in real learning conditions was conducted with 31 students using Tablet PCs and with 37 students using traditional PCs. Interestingly, the Tablet PC platform rendered the "MyTest" application more useful and usable to the students, validating our claims. (Contains 2 tables and 3 figures.)

We introduce a novel diagnostic approach for the uncovering of hidden content in layered documents, based on a photoacoustic imaging set‐up with optimised acoustic detection parameters. By exploiting the laser‐induced ultrasound following the intense absorption of pulsed optical radiation by printed ink, this traditional biomedical imaging method is proven capable of revealing text characters buried under several layers of stacked paper sheets at high spatial resolution and excellent contrast levels. Such a remarkable performance benefits from the effective combination of strong light scattering by paper fibrils and the virtually unobstructed propagation of the generated ultrasonic waves through multiple layers, enabling thus the accurate recording of text, even in double‐sided prints, with minimum shadowing artefacts. The imaging effectiveness, the implementation simplicity, the robustness, and the relatively low‐cost features offered by the proposed photoacoustic modality are anticipated to contribute in its wide adoption by the preservation of cultural heritage community, as a powerful diagnostic tool for the in‐depth investigation of complex multilayered objects. [ABSTRACT FROM AUTHOR]