On the producibility of composite position tolerance specifications for patterns of holes

A composite position tolerance verification algorithm is embedded in a simulation program to explore the producibility of three composite position tolerance variants for patterns of holes. The influence of some selective design and manufacturing variables on producibility is simulated and evaluated. It is shown that design variables such as specification variant, material condition modifier and number of holes in the pattern have a significant influence on producibility. The influence of manufacturing variables such as orientation error and numerical control path programming in the presence of axis reversal error are also simulated and discussed. Detailed graphs of these effects are presented and discussed.     

A phenology-based approach to map crop types in the San Joaquin Valley,California

An accurate and timely crop-type map is essential in water planning in California. So far, no effort has been made to effectively and efficiently identify specific crop types on an annual basis in this area. We have explored the potential of Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance images to annually map major crop types in the San Joaquin Valley, California. A phenology-based classification approach has been employed, which has extracted phenological metrics from normalized difference vegetation index (NDVI) profiles and identified crop types based on these metrics using decision trees. According to a comparison with traditional maximum-likelihood classification, this phenology-based approach has shown great advantages when the size of the training set was limited by ground-truth availability and when the central tendency was absent in agricultural systems heavily influenced by human activities.     

Probing mesopore connectivity in hierarchical nanoporous materials

Assessing connectivity of mesopores formed in microporous matrices is of importance for a wide range of applications. In this work we present an experimental study of the transport of n-hexane and nitrobenzene in a commercial activated carbon material containing purposefully introduced mesoporosity. The experimental results on diffusivities and activation energies for diffusion, as obtained using the pulsed field gradient technique of NMR, corroborate the information on pore architecture as resulting from adsorption isotherm measurement and unequivocally demonstrate the material-spanning continuity of the formed mesopore network, as a prerequisite for an unlimited transport enhancement in comparison with the purely microporous equivalent.