50 research outputs found

    A comparison of optical and radar measurements of mesospheric winds and tides

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    Optical measurements of mesospheric winds by Fabry‐Perot spectrometers, FPSs, at Mawson, 67.6°S 62.9°E, and Davis, 68.6°S 78.0°E, Antarctica are compared with similar measurements obtained using a spaced‐antenna MF radar at Davis. The FPSs observed the OH emission. Different analysis procedures, used to determine the mean wind, and amplitude and phase of the semidiurnal tide, have been compared. At these latitudes the diurnal tide is weak and the semi‐diurnal tide, although highly variable in amplitude, is usually the dominant periodicity. When comparing the amplitude and phase of the semidiurnal tide good agreement is obtained between measurements by the two instruments

    Indoor Air Quality Design and Control in Low-Energy Residential Buildings, International Energy Agency, EBC Annex 68, Subtask 5 Final Report: Field measurements and case studies

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    IEA-EBC Annex 68: Indoor Air Quality Design and Control in Low Energy Residential Buildings investigates how to ensure that future low energy buildings are able to improve their energy performance while still providing comfortable and healthy indoor environments. More specifically, Subtask 5 of Annex 68 has dealt with generation of data for the verification of the models and strategies developed in the other Annex 68 Subtasks through controlled field tests and case study presentations

    Classroom Ventilation: The Effectiveness of Preheating and Refresh Breaks: An analysis of 169 spaces at 43 schools across New Zealand

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    The COVID-19 pandemic has highlighted the importance of ventilation as a transmission mitigation strategy. However, there was a widely held concern that a drop in outdoor temperatures during winter may impact thermal comfort in the context of naturally ventilated classrooms. This concern has not been widely investigated by peer-reviewed empirical studies (Sutherland et al., 2022b). The aim of the Ministry’s ventilation monitoring initiative was to assess ventilation performance and thermal comfort by continuously measuring indoor CO2 levels, air temperature, and relative humidity in classrooms during winter, without obstructing teaching activities. A total of 43 schools, which represent a broad mix of property attributes and located across the 6 Climate Zones in New Zealand, were selected for the monitoring initiative. The CO2 monitors were deployed in about 4-6 pre-selected and representative spaces in each school. Data was retrieved from 213 spaces; of these, 44 spaces were excluded, because the initiative concentrated on teaching environments (classrooms) and those spaces were categorised as non-teaching environments (e.g., staff rooms, meeting rooms, etc.). From the 213 spaces, the data from 169 teaching spaces retrieved for the period 23 May to 26 August 2022 were analysed to ascertain the impacts of inferred human behaviours considered to be able to improve natural ventilation and detected from features of CO2 and temperature data. This analysis does not (and did not intend to) corroborate independent observation of behaviours

    Morphometric study of the root anatomy in furcation area of mandibular first molars

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    Furcation involvement in periodontal disease has been a challenge for the dentist. OBJECTIVE: The aim of this study was to investigate root dimensions in the furcation area of 233 mandibular first molars. MATERIAL AND METHODS: Digital photomicrographs were used to obtain the following measurements on the buccal and lingual surfaces of each tooth: root trunk height (RT), horizontal interadicular distance obtained 1 mm (D1) and 2 mm (D2) below the fornix and interadicular angle (IA). RESULTS: Mean± standard deviation of buccal and lingual furcation measurements were, respectively, 1.37±0.78 mm and 2.04±0.89 mm for RT; 0.86±0.39 mm and 0.71±0.42 mm for D1; 1.50±0.48 mm and 1.38±0.48 mm for D2; 41.68±13.20º and 37.78±13.18º for IA. Statistically significant differences were found between all measured parameters for buccal and lingual sides (p<0.05, paired t test). CONCLUSIONS: In conclusion, the lingual furcation of mandibular first molars presented narrower entrance and longer root trunk than the buccal furcation, suggesting more limitation for instrumentation and worse prognosis to lingual furcation involvements in comparison to buccal lesions

    Erforschung von Systemloesungen fuer transparente Verschleissschutzschichten auf Kunststoffen fuer die Optik. Teilvorhaben: Organische Schichten und organische Haftvermittlungsschichten mit kovalenter Anbindung Abschlussbericht

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    All of the scheduled investigations have been terminated. Only covalent linkages to protective coatings are promising. That fact came out from rather diverse experiments aimed to improve the adhesion. Particular problems were encountered with the chosen materials PC, CR29, PU 161, and PMMA due to their photolability during plasma CVD and due to corrosion by ubiquitous gases such as ammonia, methylamine, chlorine, nitrogen dioxide. AFM shows that gaseous amines even destroy the common hard coatings. Purposeful exposure to reactive gases under AFM control gives functionalization with recoiling of the polymer chains at the surface. Chain fissions are not tolerable. Highly cross-linked CR39 enables the direct PVD connection to SiO_2 coatings. Side-group hydrolysis without destruction of the optical surfaces is particularly attractive in the case of PMMA. Covalently attached Al_2O_3/SiO_2-coatings exhibit rather high long-term stability towards hydrolysis. The carboxylic groups that are generated should be prone to lasting covalent attachments of stress-relieving polyurethane coatings by reaction with diisocyanates. That branch was halted for reasons of capacity in favor of covalent attachment of CR39 via plasma induced grafting, even though numerous covalent attachments succeeded by simple chemical gas/solid reactions. (orig.)SIGLEAvailable from TIB Hannover: F98B80+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman
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