Shock and Release Temperatures in Molybdenum

Shock and release temperatures in Mo were calculated, taking account of heating from plastic flow predicted using the Steinberg-Guinan model. Plastic flow was calculated self-consistently with the shock jump conditions: this is necessary for a rigorous estimate of the locus of shock states accessible. The temperatures obtained were significantly higher than predicted assuming ideal hydrodynamic loading. The temperatures were compared with surface emission spectrometry measurements for Mo shocked to around 60GPa and then released into vacuum or into a LiF window. Shock loading was induced by the impact of a planar projectile, accelerated by high explosive or in a gas gun. Surface velocimetry showed an elastic wave at the start of release from the shocked state; the amplitude of the elastic wave matched the prediction to around 10%, indicating that the predicted flow stress in the shocked state was reasonable. The measured temperatures were consistent with the simulations, indicating that the fraction of plastic work converted to heat was in the range 70-100% for these loading conditions

A Scoping Review of Quality of Life Questionnaires in Glaucoma Patients

PRECIS: Multiple questionnaires exist to measure glaucoma's impact on quality of life (QoL). Selecting the right questionnaire for the research question is essential, as is patients' acceptability of the questionnaire to enable collection of relevant patient-reported outcomes. PURPOSE: QoL relating to a disease and its treatment is an important dimension to capture. This scoping review sought to identify the questionnaires most appropriate for capturing the impact of glaucoma on QoL. METHODS: A literature search of QoL questionnaires used in glaucoma, including patient-reported outcomes measures, was conducted and the identified questionnaires were analyzed using a developed quality criteria assessment. RESULTS: Forty-one QoL questionnaires were found which were analyzed with the detailed quality criteria assessment leading to a summary score. This identified the top 10 scoring QoL questionnaires rated by a synthesis of the quality criteria grid, considering aspects such as reliability and reproducibility, and the authors' expert clinical opinion. The results were ratified in consultation with an international panel of ophthalmologists (N=49) from the Educational Club of Ocular Surface and Glaucoma representing 23 countries. CONCLUSIONS: Wide variability among questionnaires used to determine vision related QoL in glaucoma and in the responses elicited was identified. In conclusion, no single existing QoL questionnaire design is suitable for all purposes in glaucoma research, rather we have identified the top 10 from which the questionnaire most appropriate to the study objective may be selected. Development of a new questionnaire that could better distinguish between treatments in terms of vision and treatment-related QoL would be useful that includes the patient perspective of treatment effects as well as meeting requirements of regulatory and health authorities. Future work could involve development of a formal weighting system with which to comprehensively assess the quality of QoL questionnaires used in glaucoma

Title: A High-Speed Four-Channel Infrared Pyrometer A High-Speed Four-Channel Infrared Pyrometer

Abstract. A high-speed, four-wavelength pyrometer has been developed for dynamic temperature measurements on samples that are heated by shock compression. The pyrometer uses a pair of off-axis parabolic mirrors to collect radiance emitted from a target of 1 mm in diameter. A single optical fiber delivers the collected radiant flux to the detector housing. Three dichroic beam splitters are used to spectrally split the light into four beams that are then focused onto an equal number of LN 2 -cooled InSb photodetectors. Broad bandwidth interference filters that are nominally centered at 1.8, 2.4, 3.4, and 5.0 µm define the wavelength ranges of the four channels. The blackbody-temperature threshold of the pyrometer is at about 400 K. The signals are recorded at intervals as short as 20 ns using a four-channel digital oscilloscope. Procedures for calibration and temperature measurements are described

A high-speed four-channel infrared pyrometer

A high-speed, four-wavelength pyrometer has been developed for dynamic temperature measurements on samples that are heated by shock compression. The pyrometer uses a pair of off-axis parabolic mirrors to collect radiance emitted from a target of 1 mm in diameter. A single optical fiber delivers the collected radiant flux to the detector housing. Three dichroic beam splitters are used to spectrally split the light into four beams that are then focused onto an equal number of LN2-cooled InSb photodetectors. Broad bandwidth interference filters that are nominally centered at 1.8, 2.4, 3.4, and 5.0 {micro}m define the wavelength ranges of the four channels. The blackbody-temperature threshold of the pyrometer is at about 400 K. The signals are recorded at intervals as short as 20 ns using a four-channel digital oscilloscope. Procedures for calibration and temperature measurements are described

Thermophysical properties of liquid Fe64/Ni36 (INVAR®)

Wire shaped invar specimens are resistively volume heated as part of a fast capacitor discharge circuit. The following properties were measured simultaneously and time resolved with sub-µs resolution: currents through the specimen by a pearson probe, voltage across the specimen by a voltage divider, temperature radiation of the specimen by an optical pyrometer and thermal expansion by a fast acting CCD-camera. These measurements allow the determination of heat capacity, enthalpy, electrical resistivity, and density as function of temperature of the alloy in the solid and liquid state in the vicinity of the melting region. Thermal conductivity of invar is estimated from electrical resistivity using Wiedeman-Franz-law.Results of invar are compared with those of earlier obtained results of pure iron and nicke

Repeatability and reproducibility of upper eyelid measurements

AIM—The aim of this study was to assess the repeatability and reproducibility by physicians of upper lid measurements and to investigate the influence of clinical experience on the learning curve effect.
METHODS—Both eyes of 22 outpatients were assessed for three basic measures of ptosis: marginal reflex distance (MRD) for upper and lower lids, upper lid skin crease (SC), and levator function (LF). Patients with variable eyelid positions were excluded. The patients were measured twice by a consultant and once by each of a clinical fellow, a specialist registrar, and a senior house officer in random order. Each observer was masked to their colleagues' results and followed a standard measurement protocol. Data were analysed using Bland-Altman plots.
RESULTS—Consultant repeatability was high and consistent, the median difference between measures being 0 for each of the four parameters. Clinically acceptable reproducibility was shown in all measurements for even the least experienced physician and was particularly consistent for extreme observations. There was evidence of a learning curve effect.
CONCLUSIONS—These results suggest that interobserver and intraobserver variability in assessment of upper lid ptosis using a standard measurement protocol is low and clinically acceptable when the technique of assessment is standardised.


A laser heating study of the CeO2 solid/liquid transition: challenges related to a refractory compound with a very high oxygen pressure

A laser heating technique is employed to study the melting behaviour of cerium dioxide, CeO2, a refractory compound with very high oxygen pressure. The strong tendency of cerium dioxide to reduce to hypostoichiometric compounds, even in the presence of trace amounts of oxygen, leads to discrepancies in the measured melting temperature depending on whether an oxidising, neutral or reducing atmosphere is used during the experiment. The purpose of this study is to measure the melting temperature of initially stoichiometric CeO2 under different controlled atmospheres: reducing or oxidizing. A high pressure cell was used to limit the oxygen losses while measuring the melting behaviour of initially stoichiometric cerium dioxide samples. The results confirm a strong influence of the atmosphere on the melting temperature: when reducing conditions were simulated a melting temperature of (2675 ± 47) K was measured, in oxidizing conditions it was measured (2743 ± 33) K. The measured values are in line with existing literature data obtained under different conditions. Only under a high buffer gas pressure, He at 15 MPa the highest reported temperature of 3000 K was observed here, although with poor repeatability