With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: North Vancouver is in a province.
text_B: The Freundlich equation or Freundlich adsorption isotherm , an adsorption isotherm , is an empirical relation between the concentration of a solute on the surface of an adsorbent to the concentration of the solute in the liquid with which it is in contact .. adsorption isotherm. adsorption isotherm. concentration. concentration. solute. solution. adsorbent. adsorbent. In 1909 , Herbert Freundlich gave an expression representing the isothermal variation of adsorption of a quantity of gas adsorbed by unit mass of solid adsorbent with pressure .. adsorbent. adsorbent. Herbert Freundlich. Herbert Freundlich. This equation is known as Freundlich adsorption isotherm or Freundlich adsorption equation .. adsorption isotherm. adsorption isotherm. As this relationship is entirely empirical , in the case where adsorption behavior can be properly fit by isotherms with a theoretical basis , it is usually appropriate to use such isotherms instead -LRB- see for example the Langmuir and BET adsorption theories -RRB- .. Langmuir. Langmuir adsorption isotherm. BET. BET theory
not_related.