A New Method to Estimate Reference Crop Evapotranspiration from Geostationary Satellite Imagery: Practical Considerations

Reference crop evapotranspiration (ETo) plays a role in irrigation advisory being of crucial importance for water managers dealing with scarce water resources. Following the ETo definition, it can be shown that total solar radiation is the main driver, allowing ETo estimates from satellite observations. As such, the EUMETSAT LSA-SAF operationally provides ETo primarily derived from the European geostationary satellite MSG. ETo estimations following the original FAO report require several meteorological observations gathered over actual well-watered grass. Here we will consider the impact of two effects on ETo using the LSA-SAF and FAO methodologies: (i) local advection, related to the impact of advection of surrounding warm dry air onto the reference non-water stressed surface; and (ii) the so-called surface aridity error, which occurs when calculating ETo according to FAO, but with input data not collected over well-watered grass. The LSA-SAF ETo is not sensitive to any of these effects. However, it is shown that local advection may increase evapotranspiration over a limited field by up to 30%, while ignoring aridity effects leads to a great overestimation. The practical application of satellite estimates of ETo provided by the LSA-SAF are discussed here, and, furthermore, water managers are encouraged to consider its advantages and ways for improvement.

Magneto-elastic SV-wave at the interface of pre-stressed surface with voids under rotation

The aim of this paper is to study the behaviour of reflection of SV- wave at a free surface under the effects of magnetic field, initial stress, rotation and voids. When a SV- wave is incident on the free surface of an elastic half space, two damped P-waves and a SV-wave is reflected. Among of these waves, P-waves are only affected by magnetic field and rotation whereas SV-wave is influenced by rotation, initial stress and magnetic field. Numerical computations are performed for the developed amplitude ratios of P-, SV- and magneto-elastic waves. This study would be useful for magneto-elastic acoustic device field and further study about nature of seismic waves.

The Loading Analysis and Strength Calculation for Slide Block Universal Spindle

The loading pressing on slide block universal spindle under the friction situation is studied, and the calculation formula of the strength is derived in this original paper. Using the calculation formula, the strength of the slide block universal spindle in the 1100-mm blooming mill in an Iron And Steel Company is calculated. Through analysis, the conclusion is obtained. The distribution law in the stressed surface of the spindle drum’s unit pressure will be changed consequence of friction and wear, and the change of the loading condition promotes the wear of the slide block and the destruction of the fork.

Luxation Test of Different Ceramic on Ceramic Couplings

Alumina and zirconia have been used for hip joint prostheses for decades. With mixtures of both materials (ZTA and ATZ) mechanical strength can be increased. The resistance against damaging of the surface of the ceramic articulation partners head and liner was investigated using a special luxation apparatus (PI-3:1997-07, Endolab GmbH, Thansau, Germany). Both new ceramic materials ZTA and ATZ showed a better resistance against roughening and damaging of the stressed surface areas during the luxation test compared to alumina.