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 ...

‎Let $tau$ be a subgroup functor and $H$ a $p$-subgroup of a finite group $G$‎. ‎Let $bar{G}=G/H_{G}$ and $bar{H}=H/H_{G}$‎. ‎We say that $H$ is $Phi$-$tau$-quasinormal in $G$ if for some $S$-quasinormal subgroup $bar{T}$ of $bar{G}$ and some $tau$-subgroup $bar{S}$ of $bar{G}$ contained in $bar{H}$‎, ‎$bar{H}bar{T}$ is $S$-quasinormal in $bar{G}$ and $bar{H}capbar{T}leq bar{S}Phi(bar{H})$‎. ‎I...

In this study, the applicability of nanofiltration (NF) membranes as a pretreatment prior to reverse osmosis (RO) in seawater desalination was investigated. The membranes used wereNF270 and NF90 as the NF membranes, while the brackish water (BW) RO membrane BW30 was used as the RO membrane. In desalination tests, permeates of the NF membraneswere collected and used as the feed to th...