deletions | additions       diff --git a/Payam and DNA.tex b/Payam and DNA.tex  index e48c225..1deb6af 100644  --- a/Payam and DNA.tex  +++ b/Payam and DNA.tex 
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\begin{enumerate}  \item What happens if an {\it interior} or bulk DNA piece approaches the pore?  \item In \citet{2013PhRvE..87d2723R} page 5, it is claimed that motion will be a superposition of longitudinal and transverse. Is this true -- won't one of them be unstable (in the case where work done in dragging is less than $T$, say)?\\   -- say)?   %%-------------------------------------------------   \begin{itemize}   \item  Reading: \citet{Binder_1939}, \citet{Burgers_1995} \item Drag resistance for a spherical particle: $F_{\rm drag}^{sph}=6\pi\eta a V$.\\   For an end-on ellipsoid: $F_{\rm drag}^{\rm ell}=\frac{4\pi\eta a V}{\ln(2a/b_0)-0.5}$.\\   For an end-on cylinder: $F_{\rm drag}^{\rm cyle}=6\pi\eta a V$.\\   For a face-on cylinder: $F_{\rm drag}^{\rm cylf}=6\pi\eta a V$.     \item Energy dissipation to viscous fluid. What is energy dissipated by electric field?   \end{itemize}   %%-------------------------------------------------  \item In \citet{Rowghanian_Grosberg_2013} page 5, second column, they use dimensional analysis to justify a steady-state approximation used in the paper: the time taken to establish the fluid velocity profile around a section of DNA must be much shorter than the time taken the DNA to ``move past'' the velocity profile.  % %%-------------------------------------------------  \begin{enumerate}  \item I want to try to do a better job than Payam's scaling argument: what are the coefficients in the ``$\# \ll 1$'' relationship? This might be interesting because of a problem acknowledged in Payam's other paper: his predictions do not fit the experimental data.  \item Dimensional analysis argument not fully understood: I guessed $t_{\rm h}\sim \ell/c_{\rm s}$ on physical grounds, but Payam says $t_{\rm h}\sim \ell^2\rho/\eta$ from dimensional analysis. What is the interpretation of Payam's $t_{\rm h}$?  % %%%%-------------------------------------------------  \begin{itemize}  \item The two $t_{\rm h}$s are measuring different things. Payam's $t_{\rm h}$ is considering the {\it diffusion }of a particle's momentum, or the vorticity of the fluid; or the characteristic time in the velocity autocorrelation of neighbouring particles. My $t_{\rm h}$ is about information flow via sonic waves: this is much smaller than the vorticity time-scale.\\  I want to think about {\it which time scale is more appropriate in this context and why?} 
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%\item (Sound speed shouldn't depend on viscosity at except for near-supersonic flow. (\href{http://iopscience.iop.org/0370-1301/66/5/303/pdf/0370-1301_66_5_303.pdf}{Or does it?} \href{http://www.engineeringtoolbox.com/sound-speed-water-d_598.html}{Speed of sound table}, \href{http://resource.npl.co.uk/acoustics/techguides/soundpurewater/content.html#LUBBERS}{$c(T,P)$ fits}.))  \end{itemize}  %%%%-------------------------------------------------  \item Payam has (equation 12) $v_{\rm DNA}=F_{\rm ext} \ln(\ell/d)/\eta\ell - \lambda E\ln(1+r_{\rm D}/d)/\eta$, which we use to calculate $t_{\rm D}$. He finds $t_{\rm D}\sim \ell\eta/E\lambda$ -- whence this simplification?  \end{enumerate}