the main objective of an extrusion die is flow balancing as an unbalanced flow causes a distorted product together with residual stress. in this paper a strategy is presented for flow balancing a u-shaped profile with different wall thicknesses. for this purpose, a choker bar is provided at thicker wall to locally restrict excessive flow passing through the thicker section. for optimal design s...

Nacrtak Chokers are wire rope slings used to secure the felled trees to the rigging during cable yarder extracting. Standard chokers are set manually by the choker-setters along the corridor, and then unhooked manually by the yarder operator at the landing. Radio-controlled chokers are also set manually but have the advantage that they can be released remotely at the landing. In addition to pos...

Pigment pattern formation in zebrafish presents a tractable model system for studying the morphogenesis of neural crest derivatives. Embryos mutant for choker manifest a unique pigment pattern phenotype that combines a loss of lateral stripe melanophores with an ectopic melanophore ;collar' at the head-trunk border. We find that defects in neural crest migration are largely restricted to the la...

A comparison of 14 currently applicable wood harvesting systems was assessed with respect to ergonomic point of view. For this purpose, the research method, based on the Hodges-Lehmann rule and the integrated work-severity rate of single machinery, was developed for ergonomic evaluation of cut-to-length, tree-length and full-tree harvesting systems. Altogether, about 130 different parameters of...

Two cable logging systems were reviewed to compare the efficiency of potential biomass extraction from remote forest sites in Ireland based on productive machine hour (PMH) and unit cost of operation (€/m). Three operational scenarios (SC) were analysed where SC I was a three man crew operation (choker setter, the carriage operator and unhooking chokers). SC II was a variation of this with a tw...

A sinusoidal grating can be viewed as a series of light and dark bars. Here we measure the contrast discrimination thresholds for light and dark bars individually, and find that the contrast discrimination thresholds for the whole sinusoid can be explained as ideal summation of the light and dark bar thresholds. We propose a model for light bar, dark bar, and sinusoidal contrast discrimination ...

Nicolas Baghdadi 1,*, Mohammad Choker 1, Mehrez Zribi 2, Mohammad El Hajj 1, Simonetta Paloscia 3, Niko E. C. Verhoest 4, Hans Lievens 4,5, Frederic Baup 2 and Francesco Mattia 6 1 IRSTEA, UMR TETIS, 500 rue François Breton, F-34093 Montpellier CEDEX 5, France; [email protected] (M.C.); [email protected] (M.E.H.) 2 CESBIO, 18 av. Edouard Belin, bpi 2801, 31401 Tou...