'Dinning Out' is the term for the traditional ritual by which officers in United Kingdom's Royal Navy are retired. It is the farewell ceremony of a retired officer of Royal Navy where a formal dinner and drink is served in the unit. Also several events are organized to boost the morale of soldiers. It is opposite to the 'Dinning In' ceremony which refers to the ritual of coming new officers.
If it's a permeable membrane then it will allow certain molecules in. If it's impermeable then it won't allow molecules in. Therefore it is the deciding feature of whether something can go into the membrane.
