Chloride Content by Weight of Concrete. Q.: For corrosion protection, ACI 318-95, Building Code Requirements for Structural Concrete, specifies maximum water-soluble chloride ion in concrete as percent by weight of cement. What are acceptable levels when measuring chloride-ion content in existing concreteâspecifically, by weight of the concrete sample?
Plasma membranes are selectively permeable, regulating the cellâs molecular traffic. Hydrophobic (nonpolar) molecules, such as hydrocarbons, can dissolve in the lipid bilayer and. pass through the membrane rapidly. Polar molecules, such as sugars, do not cross the membrane easily. Transport Membranes Transport proteins allow passage of hydrophilic substances across the membrane.
Selective permeability: Doesnât allow everything to pass through equally, has to have permission by the cell membrane e. Water is a molecule that can easily be passed through cell membrane without the help of carriers 13.Define/compare passive diffusion/active transport and simple/facilitated diffusion a. Active transport: moves molecules from lower concentration to higher with the help of ATP. Requires energy b.