A novel satellite mission concept for upper air water vapour, aerosol and cloud observations using integrated path differential absorption LiDAR limb sounding

We propose a new satellite mission to deliver high quality measurements of upper air water vapour. The concept centres around a LiDAR in limb sounding by occultation geometry, designed to operate as a very long path system for differential absorption measurements. We present a preliminary performance analysis with a system sized to send 75 mJ pulses at 25 Hz at four wavelengths close to 935 nm, to up to 5 microsatellites in a counter-rotating orbit, carrying retroreflectors characterized by a reflected beam divergence of roughly twice the emitted laser beam divergence of 15 µrad. This provides water vapour profiles with a vertical sampling of 110 m; preliminary calculations suggest that the system could detect concentrations of less than 5 ppm. A secondary payload of a fairly conventional medium resolution multispectral radiometer allows wide-swath cloud and aerosol imaging. The total weight and power of the system are estimated at 3 tons and 2,700 W respectively. This novel concept presents significant challenges, including the performance of the lasers in space, the tracking between the main spacecraft and the retroreflectors, the refractive effects of turbulence, and the design of the telescopes to achieve a high signal-to-noise ratio for the high precision measurements. The mission concept was conceived at the Alpbach Summer School 2010

Investigation of some physical and mechanical properties of concrete produced with barite aggregate

This study analyzed some physical and mechanical properties of concrete produced with barite (BaSO4) aggregate supplied from Mu province of Turkey. Unit weight (UW), water absorption (%), ultrasound pulse velocity (UPV), Schmidt hardness (SH), modulus of elasticity (ME), compressive strength (CS), tensile strength (TS) and thermal conductivity (TC) of the concrete were analyzed. For the experiments, 6 series of concrete containing 0, 10, 20, 30, 40 and 50% volume of barite aggregate were prepared. To determine thermal conductivity coefficient, this ratio was increased to 100%. Experimental results for normal concrete and barite concrete were compared

An investigation of X-ray and radio isotope energy absorption of heavyweight concretes containing barite

This study investigated the X-ray and radioisotope energy absorption capacity of heavyweight concrete containing barite aggregate. Concrete plates were prepared using differing amounts of barite aggregate instead of normal aggregate. Density–thickness–energy variations of these concretes for 85 keV, 118 keV, 164 keV, 662 keV and 1250 keV ray energies were recorded. It was observed that the concretes with greater barite content had a higher density and energy absorption capacity