The terminology of intrinsic viscosity and related functions

The confusion existing in the use of symbols and names for Kraemer's “intrinsic viscosity” and other functions related to it is illustrated and deplored.The reasonable plea is made that one name be adopted for each function and that it be used with no other meaning. To stimulate discussion and ultimate action, the following names are proposed: “specific viscosity” for η_sp; “reduced viscosity” for ηspc role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{η}{}_{\mathrm{sp}}\text{c}$$\text{η}{}_{\mathrm{sp}}\text{c}$; “inherent viscosity” for (lnηr)c role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{(}\text{ln}\text{η}{}_{\mathrm{r}}\text{)}\text{c}$$\text{(}\text{ln}\text{η}{}_{\mathrm{r}}\text{)}\text{c}$; and “intrinsic viscosity” for [η], whether determined as “limiting reduced viscosity” lim(ηspc role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{lim}\text{(}\text{η}{}_{\mathrm{sp}}\text{c}$$\text{lim}\text{(}\text{η}{}_{\mathrm{sp}}\text{c}$, or as “limiting inherent viscosity”, c→0 role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{c→0}$$\text{c→0}$ or as “limiting viscosity concentration coefficient” lim(dηrdc) role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{lim}\text{(}\text{dη}{}_{\mathrm{r}}\text{dc}\text{)}$$\text{lim}\text{(}\text{dη}{}_{\mathrm{r}}\text{dc}\text{)}$. c→0 role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{c→0}$$\text{c→0}$Often, especially in routine practice, it is the relative kinematic viscosity ν_r that is determined; unless this is shown to be numerically equal to the relative viscosity η_r, the symbols and names of the derived functions should be modified accordingly: thus, (lnνr)c role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{(}\text{ln}\text{ν}{}_{\mathrm{r}}\text{)}\text{c}$$\text{(}\text{ln}\text{ν}{}_{\mathrm{r}}\text{)}\text{c}$ inherent kinematic viscosity, [ν] intrinsic kinematic viscosity. Frequently, also, kinetic energy corrections are neglected; under these circumstances the suggested usage is t_r relative flow time, tspc role=presentation style=font-size: 90%; display: inline-block; position: relative;>$\text{t}{}_{\mathrm{sp}}\text{c}$$\text{t}{}_{\mathrm{sp}}\text{c}$ reduced flow time, [t] intrinsic flow time, etc.