2,127 research outputs found
COCAP : a carbon dioxide analyser for small unmanned aircraft systems
Unmanned aircraft systems (UASs) could provide a cost-effective way to close gaps in the observation of the carbon cycle, provided that small yet accurate analysers are available. We have developed a COmpact Carbon dioxide analyser for Airborne Platforms (COCAP). The accuracy of COCAP's carbon dioxide (CO2) measurements is ensured by calibration in an environmental chamber, regular calibration in the field and by chemical drying of sampled air. In addition, the package contains a lightweight thermal stabilisation system that reduces the influence of ambient temperature changes on the CO2 sensor by 2 orders of magnitude. During validation of COCAP's CO2 measurements in simulated and real flights we found a measurement error of 1.2 mu mol mol(-1) or better with no indication of bias. COCAP is a self-contained package that has proven well suited for the operation on board small UASs. Besides carbon dioxide dry air mole fraction it also measures air temperature, humidity and pressure. We describe the measurement system and our calibration strategy in detail to support others in tapping the potential of UASs for atmospheric trace gas measurements.Peer reviewe
Diagnostic and Therapeutic Challenges
This case is submitted by Drs. Salvador Pastor-Idoate, Manchester Royal Eye Hospital, and Manchester Vision Regeneration (MVR) Lab at NIHR/Wellcome Trust, Manchester CRF, United Kingdom; Heinrich Heimann, Royal Liverpool and Broadgreen University Hospitals NHS Trust; Pearse A. Keane, Moorfields Eye Hospital, London, United Kingdom, and Konstantinos Balaskas; Manchester Royal Eye Hospital, Manchester, United Kingdom; commented by Dr. Brandon J. Lujan, Portland, Oregon
Experimental evaluation of confidence interval procedures in sequential steady-state simulation
Sequential analysis of simulation output is generally
accepted as the most efficient way for securing
representativeness of samples of collected observations.
In this scenario a simulation experiment is stopped when
the relative precision of estimates, defined as the relative
width of confidence intervals at an assumed confidence
level, reaches the required level. This paper deals with
the statistical correctness of the methods proposed for
estimating confidence intervals for mean values in
sequential steady-state stochastic simulation. We
formulate basic rules that should be followed in proper
experimental analysis of coverage of different steadystate
interval estimators. Our main argument is that such
analysis should be done sequentially. The numerical
results of our preliminary coverage analysis of the
method of Spectral Analysis (SA/HW) and Nonoverlapping
Batch Means are presented, and compared
with those obtained by traditional, non-sequential
approaches
Bent crystal spectrometer for both frequency and wavenumber resolved x-ray scattering at a seeded free-electron laser
We present a cylindrically curved GaAs x-ray spectrometer with energy
resolution and wave-number resolution of
, allowing plasmon scattering at the resolution
limits of the Linac Coherent Light Source (LCLS) x-ray free-electron laser. It
spans scattering wavenumbers of 3.6 to \AA\ in 100 separate bins, with
only 0.34\% wavenumber blurring. The dispersion of 0.418~eV/m agrees
with predictions within 1.3\%. The reflection homogeneity over the entire
wavenumber range was measured and used to normalize the amplitude of scattering
spectra. The proposed spectrometer is superior to a mosaic HAPG spectrometer
when the energy resolution needs to be comparable to the LCLS seeded bandwidth
of 1~eV and a significant range of wavenumbers must be covered in one exposure
Требования к узлу сопряжения секций геохода
Проведен анализ работы узла сопряжения секций (УСС) геохода. Сформированы требования к узлу сопряжения секций геохода.The analysis of the operation of the bearing unit of the geokhod is carried out. The requirements for the bearing unit of the geokhod are formed
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