text:
\section{Introduction}
\label{sec:introduction}

Massless overlap fermions~\cite{Neuberger:1997fp,Neuberger:1998wv}
have provided us with a fermionic definition of topological
charge~\cite{Hasenfratz:1998ri,Niedermayer:1998bi}.  This offers the
advantage that, by truncating to the overlap modes with $|\lambda| <
\lambda_{cut}$, the effect of ultraviolet filtering can be
studied~\cite{Horvath:2002yn} without changing the gauge field itself.
A broad study of different aspects of vacuum structure, so far for
quenched QCD, has been published recently~\cite{Ilgenfritz:2007xu}.
On the other hand, during the 80's procedures of cooling or smearing of
gauge fields were proposed to exhibit the infrared structure of
gauge fields~\cite{Teper:1985ek,Ilgenfritz:1985dz}.  This has been
considered with reservations because it is difficult to assess in
which aspect the gauge field configuration could have changed under
this procedure. The practitioners of cooling/smearing, in particular
those who were focussing on vacuum structure in the form of extended,
smooth (semiclassical) structures, have continued to improve their
techniques: cooling with improved actions~\cite{Forcrand:1997sq},
restricted improved cooling~\cite{GarciaPerez:1998ru} etc).
Over-improved cooling~\cite{Perez:1993ki,Bruckmann:2004ib} has been
applied in order to prevent instantons or other topological
excitations from collapsing.

More recently, the concept of cooling/smearing has been modified in
another direction, to make it differentiable with respect to the
unsmeared field.  The so-called stout-link
smearing~\cite{Morningstar:2003gk} makes it possible to evaluate the
``force'' for the molecular dynamics in non-quenched update algorithms
with a fermionic action involving some form of ``fat'' (smeared) links
substituting the original gauge links. The concept of over-improvement
has also recently been applied to stout-link
smearing~\cite{Moran:2008ra}.

In this paper, following Ref.~\cite{Moran:2007nc} we want to
characterize the subsequent mapping ``link $\rightarrow$ stout link''
as a particular relaxation scheme, eventually leading to a finally
classical configuration.  One obvious way to discuss this process is
to record the local distribution of topological charge density
expressed by an improved~\cite{BilsonThompson:2002jk} gluonic
definition of field strength and topological density. In this paper we
shall compare the emergent structures with the topological density
provided by the overlap definition~\cite{Ilgenfritz:2007xu} with
different levels of ultraviolet filtering. Surprisingly, the overlap
topological charge density without filtering, that recently has been
found to form lower-dimensional
structures~\cite{Horvath:2003yj,Ilgenfritz:2007xu,Ilgenfritz:2007ua},
corresponds to few steps of smearing. This comparison will lead us to
a one-to-one mapping of the ultraviolet cutoff $\lambda_{cut}$ (mode
truncation in the overlap picture) to the number of stout-link
smearing iterations over a wide range of smearing iterations. In a
similar spirit, the correspondence of APE
smearing~\cite{DeGrand:2000gq}, Laplacian
filtering~\cite{Bruckmann:2005hy} and the topological density filtered
according to another Ginsparg-Wilson Dirac
operator~\cite{Gattringer:2000qu,Gattringer:2000js} has been studied
recently~\cite{Bruckmann:2006wf,Solbrig:2007nr}.

Only a few iterations of stout-link smearing are necessary before
structures become recognizable with the gluonic definition of the
topological density, and these structures are surprisingly far
from 4D extended, sign-coherent lumps, such that the topological
density compares well with the unfiltered overlap definition.
We have two criteria to establish this relation
between smearing and filtering.  First, it is the behavior of the
two-point correlation function of the topological density that emerges
from the respective definition. The second is the actual site-by-site
difference of the topological density profile over a set of lattice
configurations. The quality of the latter coincidence is surprisingly
good, which supports the reliability of both methods to explore the
vacuum structure.

Finally, however, this relation becomes loose because stout-link
smearing turns the configurations into piecewise classical fields
which apparently resemble instantons and anti-instantons. Although the
coherence among the lowest overlap modes guarantees a relatively
simple picture of the fermionic topological density and the
ultraviolet filtered gluonic field strength with low cutoff
$\lambda_{cut}$~\cite{Ilgenfritz:2007xu}, there is
no argument as to why the
overlap picture should be in correspondence to a (linkwise) classical
lattice configuration.

It is intriguing to see that the instanton-like structure that is
revealed in this late stage of smearing corresponds to the overlap
zero mode(s) and the lowest pair(s) of overlap non-zeromodes obtained
for the respective unsmeared (equilibrium) configuration. A similar
observation has already been made by
Negele {\it et al.}~\cite{Ivanenko:1997nb}. In Ref.~\cite{Ilgenfritz:2007ua} some
of us have presented a cluster analysis of individual eigenmodes of
the overlap Dirac operator. It turns out that the moderate number of
clusters that the zero and first non-zero modes consist of (at a level
of scalar density below the peak values) are pointing towards the
positions where instantons and anti-instantons appear later.

Our paper is organized as follows: in Section \ref{sec:technicalities}
we explain briefly the overlap operator and the stout-link smearing
procedure, in Section \ref{sec:matching} we describe the matching
between smearing and ultraviolet filtering, according to the two-point
correlator and according to a global fitting of the profile of charge.
In Section \ref{sec:cluster} we try to relate the clusters that both
definitions exhibit to each other.
In the final stadium of smearing
we shall confront the emergent semiclassical lumps with the lowest
eigenmodes (zero mode and lowest non-zero mode) of the original
configurations. In Section \ref{sec:conclusions} we draw conclusions
and give an outlook.

\section{Technical Details}
\label{sec:technicalities}

\subsection{Configurations and the overlap definition of topological
  density}
\label{subsec:overlapdefinition}

The configurations underlying this comparison stem from an extended
investigation published in Ref.~\cite{Ilgenfritz:2007xu}. The
configurations are taken from an ensemble of $16^3\times32$ quenched
lattices generated with the
tadpole improved L\"uscher-Weisz
action at $\beta=8.45$.

The (massless) overlap Dirac operator is constructed for the
Wilson-Dirac input kernel $D_W = M - \rho/a$,
$M$ being the massless Wilson-Dirac operator with $r=1$, and $\rho=1.4$.
The corresponding
solution of the Ginsparg-Wilson relation reads as follows
\begin{equation}
  D(0) = \frac{\rho}{a}\left( 1 + D_W/\sqrt{D_W^{\dagger} D_W} \right) =  \frac{\rho}{a}\left( 1 + \gamma_5 \mathrm{sgn} (H_W) \right) \; ,
  \label{eq:overlap}
\end{equation}
with $H_W = \gamma_5 D_W$. Circa 150 overlap eigenmodes have been
obtained per configuration. They have been used to construct
ultraviolet smeared topological densities according to a cut-off
$\lambda_{cut}=200 \mbox{~MeV}$, $400 \mbox{~MeV}$ and $635
\mbox{~MeV}$.  For half of the subset of 10 configurations
particularly considered in the present study we have also calculated
for Refs.~\cite{Ilgenfritz:2007xu,Ilgenfritz:2007ua} the overlap
topological density without mode truncation, the ``all-scale''
topological density.

The spectrum eventually consists of some zero modes,
in addition to pairs of non-zero modes of globally vanishing chirality.
The topological density can be formally obtained from the trace of the
overlap Dirac operator~\cite{Niedermayer:1998bi}
\begin{equation}
  q(x) = - \mathrm{tr} \left[ \gamma_5 \left( 1 - \frac{a}{2} D(0;x,x) \right) \right] \; .
  \label{eq:full_density}
\end{equation}
Using the spectral representation of the overlap Dirac operator, a
family of ultraviolet filtered topological charge densities labelled
by $q_{\lambda_{cut}}(x)$ can be
obtained~\cite{Horvath:2002yn,Koma:2005sw},
\begin{equation}
  q_{\lambda_{cut}}(x) = - \sum_{|\lambda|<\lambda_{cut}}
  \left( 1 - \frac{\lambda}{2} \right) \psi_{\lambda}^{\dagger}(x) \gamma_5 \psi_{\lambda}(x) \; .
  \label{eq:truncated_density}
\end{equation}
The topological charge of each configuration
fulfills the Atiyah-Singer index theorem~\cite{Hasenfratz:1998ri}
\begin{equation}
  Q = n_{-} - n_{+} \; .
  \label{eq:Atiyah-Singer}
\end{equation}
Note that the zero modes of any given configuration carry the same
chirality.

In this paper we shall point out that
the above-mentioned  family of densities is well
represented by the gluonic topological density after an appropriate
number of iterations
of stout-link smearing.

\subsection{Over-improved stout-link smearing}
\label{subsec:smearing}

In Refs.~\cite{Moran:2008ra,Moran:2007nc} two of us have motivated the
stout-link smearing with respect to a specific over-improved
action. The concept of over-improved action arose from the observation
that the Wilson one-plaquette action does not guarantee the stability
of instantons~\cite{Gockeler:1989qg}.  Even with the Symanzik improved
action including $1\times1$ plaquettes and $1 \times 2$ rectangular
loops, for a classical instanton solution of size $\rho_{inst}$ placed
on the lattice, the action is obtained as
\begin{equation}
  S^{inst} = \frac{8\pi^2}{g^2}
  \left[ 1 - \frac{17}{210}\left(\frac{a}{\rho_{inst}}\right)^4 \right] \; .
  \label{eq:instanton_without_epsilon}
\end{equation}
Following Garcia Perez {\it et al.}~\cite{Perez:1993ki},
Ref.~\cite{Moran:2008ra} proposes to modify the relative
contribution of plaquette and rectangular terms, parametrized by a
parameter $\epsilon$. For the Symanzik action this reads as follows
\begin{equation}
  S(\epsilon) = \beta \sum_x \sum_{\mu < \nu} \left[\frac{5-2\epsilon}{3}~(1 - P_{\mu\nu}(x))
    - \frac{1-\epsilon}{12}\left(1 - R_{\mu\nu}(x) + 1 - R_{\nu\mu}(x) \right) \right] \; ,
  \label{eq:overimproved_Symanzik}
\end{equation}
interpolating between Wilson ($\epsilon=1$) and Symanzik action
($\epsilon=0$).  As usual, $\beta=6/g^2$.
The plaquettes are denoted as
$$P_{\mu\nu} = \frac{1}{3}
\mathrm{Re~Tr}~\left(U_{x,\mu}
                     U_{x+\hat{\mu},\nu}
	   	     U^{\dagger}_{x+\hat{\nu},\mu}
		     U^{\dagger}_{x,\nu}\right)$$
and the traces of the rectangular loops as
$$R_{\mu\nu} = \frac{1}{3}
\mathrm{Re~Tr}~\left(U_{x,\mu}
                     U_{x+\hat{\mu},\mu}
		     U_{x+2\hat{\mu},\nu}
		     U^{\dagger}_{x+\hat{\nu}+\hat{mu},\mu}
		     U^{\dagger}_{x+\hat{\nu},\mu}
		     U^{\dagger}_{x,\nu}\right) \; . $$
With this action the instanton action behaves as
\begin{equation}
  S^{inst} = \frac{8\pi^2}{g^2} \left[ 1 - \frac{\epsilon}{5}
  \left(\frac{a}{\rho_{inst}}\right)^2
    +\frac{14\epsilon-17}{210}\left(\frac{a}{\rho_{inst}}\right)^4 \right] \; .
  \label{eq:instanton_with_epsilon}
\end{equation}
In Ref.~\cite{Moran:2007nc} a value $\epsilon=-0.25$ was found to provide
an instanton action almost independent of the radius for
$\rho_{inst} > 1.5 a$.

The stout-link iteration solves the equation of motion (without momentum)
\begin{equation}
U^{old}_{x\mu} \to U^{new}_{x\mu} =
\exp\left( - \rho_{sm}~\frac{\delta S(\epsilon)} {\delta U_{x\mu}} \right)~U^{old}_{x\mu}
\label{eq:stout_link_iteration}
\end{equation}
in parallel, with a ``time step'' $\rho_{sm}$.
No projection onto the group $SU(3)$ is required in distinction to APE
smearing.
The derivative is the traceless antihermitean part of a sum of untraced loops
$$\frac{\delta S(\epsilon)}{\delta U_{x\mu}}=
\frac{5 - 2\epsilon}{3} \sum \left(\mathrm{1x1~loops~touching~} U \right)
+ \frac{1 - \epsilon}{12} \sum \left(\mathrm{1x2+2x1~loops~touching~} U \right)_{|\mathrm{antiherm~traceless}}$$
with $U_{x\mu}$ in the leftmost position.
This method has been discussed in Ref.~\cite{Moran:2007nc}
with respect to the two-point
correlator of the topological density. The differences between
quenched and dynamical ensembles of configurations with respect to the
distribution of topological density have been demonstrated. The
instanton-like features are seen to become stronger with more and more
iterations of (\ref{eq:stout_link_iteration}).
The resemblance to instantons was stated~\cite{Moran:2007nc} by a close
correlation --
maximum by maximum of the modulus of the topological density --
between the ``instanton size'', determined by the curvature of $|q(x)|$
in the maximum position $x_0$ of the cluster, and the value of the
density $|q(x_0)|$.

The local lattice operator~\cite{BilsonThompson:2002jk} to represent
the topological density for the stout-link smeared configurations is
based on a highly improved field-strength tensor,
\begin{equation}
  F^{imp}_{\mu\nu}(x)
  = k_1 C^{(1,1)}_{\mu\nu}(x) + k_2 C^{(2,2)}_{\mu\nu}(x)
  + k_3 C^{(1,2)}_{\mu\nu}(x) + k_4 C^{(1,3)}_{\mu\nu}(x)
  + k_5 C^{(3,3)}_{\mu\nu}(x)
\end{equation}
with
\begin{eqnarray}
  k_1 & = & \frac{19}{9} - 55 k_5 \; , \nonumber \\
  k_2 & = & \frac{1}{36} - 16 k_5 \; , \nonumber \\
  k_3 & = & -\frac{32}{45} + 64 k_5 \; , \nonumber \\
  k_4 & = & \frac{1}{15} - 6 k_5 \; , \nonumber \\
\end{eqnarray}
and with
\begin{equation}
  C^{(nm)}_{\mu\nu}(x) = \frac{1}{8} \left( W^{(n,m)}_{\mu\nu}(x)
    + W^{(m,n)}_{\mu\nu}(x) \right)
\end{equation}
being a symmetrized ``clover sum'' of
$(n\times\hat{\mu},m\times\hat{\nu})$ Wilson loops around the site
$x$. A 3-loop improved field strength tensor can be achieved chosing
$k_5=1/90$, such that $k_3 = k_4 = 0$.  The topological charge density
is then represented in the form
\begin{equation}
  q_{sm}(x) =  \frac{g^2}{16\pi^2} \mathrm{Tr}~\left( F_{\mu\nu}\tilde{F}_{\mu\nu}\right) \; .
\label{eq:gluonic_density}
\end{equation}

\section{Matching stout-link smearing to overlap filtering}
\label{sec:matching}

\subsection{Matching the two-point correlator}
\label{subsec:correlator}

The two-point correlators for stout-link smearing and overlap
filtering are matched using a minimization of the sum of the absolute
difference between the correlators. That is, we compute
\begin{equation}
  \mathrm{min}\,\left( \sum_x |\langle q(x)q(0) \rangle_{sm} - \langle
    q(x)q(0) \rangle_{\lambda_{cut}}| \right)
  \label{eq:matchqxqy}
\end{equation}
as a function of the number of smearing sweeps, $n_{sw}$,
for fixed $\lambda_{cut}$.

The topological charge of each overlap filtered configuration is
integer valued because they satisfy the Atiyah-Singer index
theorem~(\ref{eq:Atiyah-Singer}). For stout-link smearing it can take
up to $10$ sweeps of smearing to achieve an integer charge on these
$16^3\times32$ lattices. In order to
compare overlap filtering and stout-link smearing for $n_{sw} < 10$
in a fair way a non-perturbative
normalization is applied. Given that we know the topological charge $Q$
from the overlap configurations, we calculate, for each
number of smearing sweeps $n_{sw}$, a normalization factor $Z_{sm}$ via
\begin{equation}
  Q = Z_{sm} \sum_x q_{sm}(x) \,,
  \label{eq:zswnormalization}
\end{equation}
and $q_{sm}(x)$ is then normalized through $q_{sm}(x) \rightarrow
Z_{sm}\, q_{sm}(x)$. This ensures that $Q_{sm} = Q$. We also experimented
with an alternate normalization where we matched the absolute values of
the topological charge density, however this
proved less fruitful.

Typical values of $Z_{sm}$ are provided in
\Tab{table:Zfactors}.
\begin{table}
  \begin{center}
    \begin{tabular}{c@{\hspace{10pt}}c@{\hspace{10pt}}c@{\hspace{10pt}}c@{\hspace{10pt}}c@{\hspace{10pt}}c}
      \hline
      \hline
      $n_{sw}$ & $Q = -8$ & $Q = 0$ & $Q = -1$ & $Q = -7$ & $Q = 0$ \\
      \hline
      \hline
      1 &   0.9954 &  -0.0001 &   1.0054 &   0.6442 &   0.0000 \\
      2 &   0.9634 &  -0.0001 & -21.5369 &   0.7987 &  -0.0001 \\
      3 &   0.9494 &  -0.0001 &   3.6497 &   0.8990 &  -0.0001 \\
      4 &   0.9585 &  -0.0002 &   1.8690 &   0.9485 &  -0.0001 \\
      5 &   0.9760 &  -0.0004 &   1.4537 &   0.9728 &  -0.0001 \\
      6 &   0.9903 &  -0.0008 &   1.2736 &   0.9843 &  -0.0002 \\
      7 &   0.9982 &  -0.0015 &   1.1725 &   0.9894 &  -0.0004 \\
      8 &   1.0010 &  -0.0030 &   1.1105 &   0.9915 &  -0.0006 \\
      \hline
    \end{tabular}
  \end{center}
  \caption{Table of $Z_{sm}$ values for the initial five
    configurations. The normalization procedure is only valid for $Q
    \ne 0$ and works best for large $|Q|$. The fluctuating
    values for the configuration with $Q=-1$ occuring at
    $n_{sw} = 2$ are due to $Q_{sm}$ being approximately $0$ at this point.}
  \label{table:Zfactors}
\end{table}
For obvious reasons, it is only possible to extract a $Z_{sm}$ factor
for $Q \ne 0$, and the procedure works best for $Q$ far from
zero. Consequently, the best results are found for the configurations
where $Q = -7$ and $-8$, where the $Z_{sm}$ values rapidly approach
1. This is also the case for the configuration with $Q=-1$, however
$Z_{sm}$ fluctuates at $n_{sw} = 2$, which is due to $Q_{sm}$ being
approximately $0$ at this point.

\begin{table}
  \begin{center}
    \begin{tabular}{c@{\hspace{20pt}}cc@{\hspace{20pt}}cc@{\hspace{20pt}}cc@{\hspace{20pt}}cc@{\hspace{20pt}}cc}
      \hline
      \hline
      $\lambda_{cut}$ & \multicolumn{2}{l}{$Q = -8$}&\multicolumn{2}{l}{$Q = 0$}&\multicolumn{2}{l}{$Q = -1$}&\multicolumn{2}{l}{$Q = -7$}&\multicolumn{2}{l}{$Q = 0$}\\
      \hline
      \hline
      full density & 005 & 005 & 005 & --- & 005 & 005 & 005 & 004 & 005 & ---\\
      all known modes & 039 & 039 & 043 & --- & 036 & 036 & 038 & 037 & 034 & ---\\
      634 MeV      & 052 & 052 & 064 & --- & 048 & 048 & 055 & 055 & 048 & ---\\
      400 MeV      & 127 & 127 & 183 & --- & 109 & 108 & 139 & 138 & 115 & ---\\
      200 MeV      & 248 & 247 & 300 & --- & 232 & 232 & 300 & 300 & 271 & ---\\
      \hline
    \end{tabular}
  \end{center}
  \caption{The best matches for the two-point correlators of five
    different configurations as determined by \Eq{eq:matchqxqy}. For
    each configuration, the two columns give the number of smearing
    sweeps that correspond to the best match for a given level of UV
    filtering. In each case the left column gives the best match for
    the unnormalised gluonic density and the right column gives the
    best match for the gluonic density normalised with $Z_{sm}$ (see
    text). The right columns for the $Q=0$ configurations are absent
    because the normalization procedure fails in these cases.}
  \label{table:match-correl}
\end{table}
In Table~\ref{table:match-correl} we present the best matches for the
two-point correlators between the filtered overlap densities and the
stout-link smeared gluonic densities. Configurations have been used
for which the unfiltered overlap topological density (full density)
has been measured. The correlators of the fermionic topological density
including
all known modes, with $\lambda_{cut}=634 \mathrm{~MeV}$, with
$\lambda_{cut}=400 \mathrm{~MeV}$ and with $\lambda_{cut}=200
\mathrm{~MeV}$ are matched against the smeared gluonic correlators.

\begin{figure*}
  \vspace*{0.8cm}
  \includegraphics[width=0.44\textwidth,angle=90]{qxqy.0111.full.ps}
  \caption{The two-point function of the fermionic topological density
    for one configuration shown without mode truncation compared with
    the bosonic definition after 5 steps of smearing.}
  \label{fig:Fig1}
\end{figure*}
\begin{figure*}[!h]
  \vspace*{0.8cm}
  \includegraphics[width=0.44\textwidth,angle=90]{qxqy.0111.Zfactor.ps}
  \caption{The same as in Fig. 1 with the effect of the
    renormalization factor $Z_{sm}=Q_{ferm}/Q_{sm}$ also shown.
    ($Q_{ferm}=8$, $Q_{sm}=8.19$)}
  \label{fig:Fig2}
\end{figure*}
\begin{figure*}[!h]
  \vspace*{0.8cm}
  \includegraphics[width=0.44\textwidth,angle=90]{qxqy.0111.634MeV.ps}
  \caption{The two-point function of the fermionic topological density
    with an UV cutoff at $\lambda_{cut}=634 \mathrm{~MeV}$ compared
    with the bosonic definition after 52 steps of smearing when the
    correlator is fitted best. Smearing after 45 steps leads to
    the best global matching of the density $q_{\lambda_{cut}}$ with
    $\lambda_{cut}=634 \mathrm{~MeV}$, but the correlator is steeper.}
  \label{fig:Fig3}
\end{figure*}
We show in Fig. 1 the two-point correlator of the topological density
for a single configuration represented by the unfiltered fermionic
topological density (full density) of Eq.~(\ref{eq:full_density}) of the
equilibrium configuration on one hand and for the gluonic definition
of Eq.~(\ref{eq:gluonic_density}) after 5 smearing steps. It is
remarkable that the two correlators follow each other's fluctuations
at larger distance. There is some difference in normalization of the
negative peak. This configuration has $Q_{ferm}=-8$, and the gluonic
definition gives $Q_{sm}=-8.19$.  In this case the
``non-perturbative'' renormalization would even slightly increase the
difference between the curves
as the three curves in Fig. 2 show.

In Fig.~3 the density-density two-point correlator for the same
configuration is compared for an ultraviolet cutoff $\lambda_{cut}=634
\mathrm{~MeV}$ for the fermionic, overlap definition and the gluonic
definition after 52 smearing steps. The filtered correlators match
perfectly.  The third curve shows the correlator with the gluonic
definition after 45 smearing steps.  This refers to the case of an
optimal point-by-point matching of the densities, as discussed in the
next section.  The corresponding correlator is somewhat higher and
steeper because it uses slightly less smearing iterations.

\begin{figure*}
  \vspace*{0.8cm}
  \includegraphics[width=0.44\textwidth,angle=90]{qxqy.0111.400MeV.b.ps}
  \caption{The same as Fig. 3 with an UV cutoff at $\lambda_{cut}=400
    \mathrm{~MeV}$ fitted best by the bosonic definition after 127
    steps of smearing. Smearing after 103 steps leads to the best
    global matching of the densities, but the correlator is steeper.}
  \label{fig:Fig4}
\end{figure*}
Fig.~4 shows the same configuration for a lower ultraviolet cutoff
$\lambda_{cut}=400 \mathrm{~MeV}$.  After 127 smearing steps the
correlator for the gluonic definition fits the correlation function
perfectly. Somewhat less smearing steps (103), again optimally fitting the
fermionic topological density point by point, tend to overestimate the correlator.

\begin{figure*}
  \vspace*{0.8cm}
  \includegraphics[width=0.44\textwidth,angle=90]{qxqy.0111.200MeV.ps}
  \caption{The same as Figs. 3 and 4, now with an UV cutoff at
    $\lambda_{cut}=200 \mathrm{~MeV}$ fitted best by 248 sweeps of
    smearing. 260 sweeps of smearing gives the best match for the
    topological charge densities.}
  \label{fig:Fig5}
\end{figure*}

All smeared correlators discussed above were generated using a
smearing parameter of $\rho_{sm} = 0.06$. By using a different value for
$\rho_{sm}$ it is possible that a different number of smearing sweeps will
provide the best fit. This is because the amount of smearing applied
to a gauge field is proportional to $\rho_{sm}\,n_{sw}$.
By varying $\rho_{sm}$
as well as the number of sweeps one has greater fine-grained control
over the matching. Using a variable $\rho_{sm}$, but holding $n_{sw} = 5$
fixed, and applying this to the same configuration considered previously
we find that
$\rho_{sm} = 0.055$ provides the best match for the unfiltered topological
density.

A comparison of some different
values for for the smearing parameter is provided in
\Fig{fig:qxqy.r05.r06.r055}.
\begin{figure*}
  \vspace*{0.8cm}
  \includegraphics[width=0.44\textwidth,angle=90]{qxqy.r05.r06.r055.ps}
  \caption{A comparison of the smeared two-point function for three
    different values of the smearing parameter, $\rho_{sm}$. The
    configuration shown is the same as that used in the previous
    figures. A best match as dictated by \Eq{eq:matchqxqy} is given by
    $\rho_{sm} = 0.055$, however $\rho_{sm} = 0.06$ gives the
    best match for the $x$-intercept.}
  \label{fig:qxqy.r05.r06.r055}
\end{figure*}
As expected, increasing $\rho_{sm}$ results in a suppression of the
negativity of the
two-point correlator. Although $\rho_{sm} = 0.055$ provides the best match
through a minimization of the sum of the differences in the two-point
functions, $\rho_{sm} = 0.06$ gives the best match for the $x$-intercept.
The two-point function for this larger $\rho_{sm}$ also appears to have a
similar shape to the two-point function of the full fermionic topological
density.

\subsection{Matching the fermionic and gluonic topological density point by point}
\label{subsec:landscape}

We now aim to match the filtered fermionic densities with the smeared
gluonic densities through a point-by-point matching of the respective
topological charge densities $q_{\lambda_{cut}}(x)$ and $q_{sm}(x)$.
Given some filtered
fermionic topological charge density we compare it against the gluonic density
$q_{sm}(x)$ after some number of sweeps by calculating the absolute
value of the difference between the respective $q$ at each $x$. To find the best
match we compute the minimum of the sum of the differences,
\begin{equation}
  \mathrm{min}\,\left( \sum_x | q_{sm}(x) - q_{\lambda_{cut}}(x) | \right) \; ,
  \label{eq:matchqx}
\end{equation}
as a function of the number of smearing sweeps, $n_{sw}$,
for fixed $\lambda_{cut}$.
The non-perturbative normalization of Eq.~(\ref{eq:zswnormalization})
will also be applied. The best matches are presented in
Table~\ref{table:match-x-by-x}.
\begin{table}
  \begin{center}

    \begin{tabular}{c@{\hspace{20pt}}cc@{\hspace{20pt}}cc@{\hspace{20pt}}cc@{\hspace{20pt}}cc@{\hspace{20pt}}cc}
      \hline
      \hline
      $\lambda_{cut}$ & \multicolumn{2}{l}{$Q = -8$}&\multicolumn{2}{l}{$Q = 0$}&\multicolumn{2}{l}{$Q = -1$}&\multicolumn{2}{l}{$Q = -7$}&\multicolumn{2}{l}{$Q = 0$}\\
      \hline
      \hline
      full density & 300 & 005 & 300 & --- & 300 & 006 & 300 & 005 & 300 & --- \\
      all known modes & 037 & 036 & 037 & --- & 035 & 035 & 035 & 035 & 033 & --- \\
      634 MeV      & 045 & 045 & 048 & --- & 044 & 044 & 048 & 048 & 044 & --- \\
      400 MeV      & 103 & 103 & 098 & --- & 103 & 103 & 087 & 087 & 093 & --- \\
      200 MeV      & 261 & 260 & 300 & --- & 236 & 236 & 192 & 191 & 187 & --- \\
      \hline
    \end{tabular}
  \end{center}
  \caption{Best matches for $q(x)$ between the
    filtered overlap densities and smeared gluonic densities. The left
    columns contain the best matches with the unnormalised gluonic
    densities, and the right columns contain the best matches when
    including the $Z_{sm}$ factor. We see the importance of the
    $Z_{sm}$ normalization factor when attempting the match the full
    fermionic density. The right columns are absent for the $Q=0$
    configurations because the normalization method does not work for
    this $Q$.}
  \label{table:match-x-by-x}
\end{table}
For a small number of sweeps the importance of the $Z_{sm}$
normalization is apparent. Visualizations of some configurations are
shown later in Section~\ref{sec:cluster}.

\subsection{Towards the no-smearing limit}
\label{subsec:nosmearing}

Increased smearing leads to flattening of the Euclidean two-point
function. It follows that less sweeps of smearing leads to
an increasing
negative dip in the correlator, and we now study the behaviour of the
two-point function in the limit $n_{sw} \rightarrow 0$. After only one
or two sweeps of smearing there is a non-trivial renormalization that
must be applied to the topological charge density. From
\Tab{table:Zfactors} we see that after three smearing iterations the
$Z_{sm}$ factors for the $Q = -7$ and $Q = -8$ configurations are in
relatively good agreement. We can therefore study the correlator for
$n_{sw} \ge 3$, averaging over these two configurations.

Such a comparison leads to a series of correlators which
are displayed in Fig.~\ref{fig:qxqy.3.4.5.sweeps}.
The $x$-intercept also moves further towards zero.
\begin{figure*}[h]

  \begin{center}
    \includegraphics[width=0.44\textwidth,angle=90]{qxqy.3.4.5.sweeps.ps}
    \caption{The two-point function as a function of smearing
      sweeps. The correlator has been averaged over the two
      configurations with $Q=-7$ and $Q=-8$. Both charge densities
      were normalised by an average of the $Z_{sm}$ values for the two
      configurations. As the number of sweeps is decreased the
      negative dip increases in magnitude and the $x$-intercept moves
      further toward zero.}
  \label{fig:qxqy.3.4.5.sweeps}

  \end{center}
\end{figure*}

\section{Comparison of topological clusters}
\label{sec:cluster}

\subsection{Clusters of both topological densities compared for weak
  stout-link smearing}
\label{subsec:cluster1}

Using the matching of Eq.~(\ref{eq:matchqx}) we are able to directly
compare the overlap topological charge density with some level of UV
filtering to a given number of stout-link smearing sweeps. In an early
stadium of stout-link smearing the topological density does not yet
show classical, instanton-like features.
What is meant by ``instanton-like features'' and how they gradually
emerge from stout-link smearing is illustrated for a configuration
with $Q=-1$ in Fig.~\ref{fig:instantonlike}. The solid lines represent
the relation
\begin{equation}
|q(x_0)| = \frac{6}{\pi^2 \rho_{inst}^4} \; ,
\end{equation}
typical for the (anti)instanton solution, between the gluonic topological
charge density in the maxima $x_0$ of the modulus of the density $|q_{sm}(x)|$
and the ``instanton radii'' $\rho_{inst}$ obtained from a fit of the curvature
of the action density in the points neighbouring $x_0$.
\begin{figure*}[!h]

  \begin{center}
      \includegraphics[width=0.369\textwidth,angle=90]{fiti.0123.005swp.ps} \\
      \vspace{0.5cm}
      \includegraphics[width=0.369\textwidth,angle=90]{fiti.0123.040swp.ps} \\
      \vspace{0.5cm}
      \includegraphics[width=0.369\textwidth,angle=90]{fiti.0123.200swp.ps}
    \caption{Three scatterplots showing the increasing instanton-like
     correlation between the gluonic topological charge density in the
     maxima $x_0$ of its modulus $|q_{sm}(x)|$ and the ``instanton radii''
     $\rho_{inst}$ (see text). The solid lines represent the
     (anti)instanton-like relation between the two cluster parameters.
     The upper plot shows a huge number of maxima after 5 smearing steps,
     without any relation between density and size. The middle and bottom
     plots show a decreasing number of maxima and an inreasing accuracy of
     the instanton-like relation after 40 and 200 smearing steps,
     respectively.}
    \label{fig:instantonlike}
  \end{center}

\end{figure*}
\begin{figure*}[h]

  \begin{center}
    \begin{tabular}{cc}
      \includegraphics[width=0.50\textwidth,angle=0]{0123.peaks.sw005.jpg.ps} &
      \hspace{0.5cm}
      \includegraphics[width=0.50\textwidth,angle=0]{0123.peaks.sw040.jpg.ps} \\
    \end{tabular}
    \caption{The gluonic topological charge density very close to the
      maxima in some timeslice of the same configuration as analyzed
      in Fig.~\ref{fig:instantonlike} after 5 (left) and 40 stout-link
      smearing iterations (right). In color online: negative density
      blue/green, positive density red/yellow. In grey-scale:
      negative density dark, positive density light.}
  \label{fig:shapes}
  \end{center}

\end{figure*}
\begin{figure*}[h]

  \begin{center}
    \begin{tabular}{cc}
      \includegraphics[width=0.50\textwidth,angle=0]{qx.0126.634MeV.overlap.jpg.ps} &
      \hspace{0.5cm}
      \includegraphics[width=0.50\textwidth,angle=0]{qx.0126.634MeV.sw048.jpg.ps} \\
    \end{tabular}
    \caption{The fermionic topological charge density of a $Q = 0$
      configuration with $\lambda_{cut}=634 \mathrm{~MeV}$ (left)
      compared with 48 sweeps of over-improved stout-link smearing
      (right). In color online: negative density blue/green,
      positive density red/yellow. In grey-scale: negative density
      dark, positive density light.}
  \label{fig:qx.634MeV}
  \end{center}

\end{figure*}
\begin{figure*}[h]

  \begin{center}
    \begin{tabular}{cc}
      \includegraphics[width=0.50\textwidth,angle=0]{qx.0111.400MeV.overlap.jpg.ps} &
      \hspace{0.5cm}
      \includegraphics[width=0.50\textwidth,angle=0]{qx.0111.400MeV.sw103.jpg.ps} \\
    \end{tabular}
    \caption{The fermionic topological charge density of a $Q = -8$
      configuration with $\lambda_{cut}=400 \mathrm{~MeV}$ (left)
      compared with 103 sweeps of over-improved stout-link smearing
      (right). In color online: negative density blue/green,
      positive density red/yellow. In grey-scale: negative density
      dark, positive density light.}
  \label{fig:qx.400MeV}
  \end{center}

\end{figure*}
\begin{figure*}[h]

  \begin{center}
    \begin{tabular}{cc}
      \includegraphics[width=0.50\textwidth,angle=0]{qx.0301.200MeV.overlap.jpg.ps} &
      \hspace{0.5cm}
      \includegraphics[width=0.50\textwidth,angle=0]{qx.0301.200MeV.sw192.jpg.ps} \\
    \end{tabular}
    \caption{The fermionic topological charge density of a $Q = -7$
      configuration with $\lambda_{cut}=200 \mathrm{~MeV}$ (left)
      compared with 192 sweeps of over-improved stout-link smearing
      (right). In color online: negative density blue/green,
      positive density red/yellow. In grey-scale: negative density
      dark, positive density light.}
  \label{fig:qx.200MeV}
  \end{center}

\end{figure*}
The upper plot has to be considered with a grain of salt because a closer
look at the maxima reveals a substantial lack of isotropy of the peaks
of topological density which is however implicitely assumed in
the fits of $\rho_{inst}$.
The marked difference in this respect between 5 and 40 smearing steps is
visible in Fig.~\ref{fig:shapes} showing a certain timeslice of the same
configuration as in Fig.~\ref{fig:instantonlike}.

For a moderate amount of smearing and filtering, respectively, the two
topological density definitions are faithfully exhibiting the
outstanding clusterization of charge, provided the cut-off
$\lambda_{cut}$ and the number of stout-link smearing steps are
optimally tuned to each other.
This is exemplified by Fig.~\ref{fig:qx.634MeV} which shows the same
time-slice of a $Q=0$ configuration, on the left-hand side portrayed
by the overlap-fermionic topological density with $\lambda_{cut}=634
\mathrm{~MeV}$ and on the right-hand side by the gluonic topological
density after 48 stout-link smearing steps.

In Fig.~\ref{fig:qx.400MeV} we show the fermionic density of the $Q =
-8$ configuration, with $\lambda_{cut}=400\mathrm{~MeV}$ and the
gluonic density after 103 stout-link smearing steps. In this stadium
of smearing, the bias in favor of classical lumps is already visible.

Besides the similarity between the two methods, the tendency towards
classical lumps becomes obvious in Fig.~\ref{fig:qx.200MeV}.  This
figure shows the $Q = -7$ configuration with a cutoff of
$\lambda_{cut} = 200~\mathrm{MeV}$. At this level of UV filtering the
best match is provided by 193 sweeps of over-improved stout-link
smearing. In this stadium of smearing, in particular because of the
over-improved action built into the smearing, the minority
positive charge has
become stabilized compared with what the fermionic view shows.

\subsection{Zero modes and lowest non-zeromodes and the instanton
  content after long smearing}
\label{subsec:cluster2}

For long smearing with essentially
more than 100 smearing steps, the similarity of
the topological densities slowly becomes less perfect. Still, the
position of the gluonic topological lumps is not completely arbitrary
from the point of view of the original configuration. The zero modes
(if $Q\ne0$) and the lowest non-zero modes contain a high predictive
power over where these lumps will appear.

\begin{figure*}[h]

  \begin{center}
    \begin{tabular}{cc}
      \includegraphics[width=0.50\textwidth,angle=0]{zm.0123-charge-200swp-rho-0.jpg.ps} &
      \hspace{0.5cm}
      \includegraphics[width=0.50\textwidth,angle=0]{zm.0123-rho-0.jpg.ps} \\
    \end{tabular}
    \caption{The gluonic topological charge density after 200 smearing
      sweeps (left) and the scalar density of the zero mode (right)
      for a $Q=-1$ configuration. One can see how the zero mode
      extends over only regions of negative charge. All extended
      sign-coherent objects seen are good local approximations to
      instantons or anti-instantons in the centre. In color online:
      negative density is blue/green, positive density is red/yellow
      (left), and scalar density is blue/green (right). In grey-scale:
      negative density dark, positive density light (left).}
  \label{fig:zm.0123-rho-0}
  \end{center}

\end{figure*}
\begin{figure*}[h]

  \begin{center}
    \begin{tabular}{cc}
      \includegraphics[width=0.50\textwidth,angle=0]{zm.0130-charge-200swp-rho-0.jpg.ps} &
      \hspace{0.5cm}
      \includegraphics[width=0.50\textwidth,angle=0]{zm.0130-rho-0.jpg.ps} \\
    \end{tabular}
    \caption{The gluonic topological charge density after 200 smearing
      sweeps (left) and the scalar density of the zero mode (right)
      for a $Q=1$ configuration. In this case the high density regions
      of the zero mode are centred on lumps of positive charge. Again
      all objects are good approximations to classical instantons. In
      color online: negative density is blue/green, positive density
      is red/yellow (left), and scalar density is red/yellow
      (right). In grey-scale: negative density dark, positive density
      light (left).}
  \label{fig:zm.0130-rho-0}
  \end{center}

\end{figure*}
For 200 smearing steps, this is illustrated in
Fig.~\ref{fig:zm.0123-rho-0} by a $Q=-1$ configuration. In the left
panel the gluonic topological density is shown, in the right panel the
scalar density of the zero mode. The zero mode covers three distinct
centers of topological charge of appropriate sign only in the selected
time-slice.
Two more examples of total charge $Q=\pm1$ are shown in
Figs.~\ref{fig:zm.0130-rho-0}
and~\ref{fig:zm.0141-rho-0}. One sees that the zero mode does not
always cover all regions of appropriate charge. In other words, the
gluonic version of the topological charge density for some clusters
- even in a late stadium of smearing - may be built by non-zero modes.
This leads us to revise the naive expectations according to which each
zero mode would be residing on one lump of excess topological charge,
for which a cluster charge of $Q_{cl}=\pm1$ would be suggested by the
instanton model.
\begin{figure*}[!ht]

  \begin{center}
    \begin{tabular}{cc}
      \includegraphics[width=0.50\textwidth,angle=0]{zm.0141-charge-200swp-rho-0.jpg.ps} &
      \hspace{0.5cm}
      \includegraphics[width=0.50\textwidth,angle=0]{zm.0141-rho-0.jpg.ps} \\
    \end{tabular}
    \caption{The gluonic topological charge density after 200 smearing
      sweeps (left) and the scalar density of the zero mode (right)
      for another $Q=-1$ configuration. The high density regions of
      the zero mode are again centred on lumps of negative charge. All
      topological objects are good approximations to classical
      instantons. In color online: negative density is blue/green,
      positive density is red/yellow (left), and scalar density is
      blue/green (right). In grey-scale: negative density dark,
      positive density light (left).}
  \label{fig:zm.0141-rho-0}
  \end{center}

\end{figure*}
In fact, in Ref.~\cite{Ilgenfritz:2007ua} it has been demonstrated that
the zero modes typically are simultaneously carried by a moderate number
of centers below the peak density, before they start percolating throughout
the whole lattice at an even lower level of the scalar density. Here we
additionally learn that all theses centers are marked by lumps of topological
charge of appropriate sign, however not necessarily all lumps are covered.

For these same three configurations we now consider the distribution
of the lowest non-zero modes. Starting with the first $Q=-1$
configuration, we present the scalar and pseudoscalar densities of the
first non-zero mode in Fig.~\ref{fig:zm.0123-rho-1}.
\begin{figure*}[!h]

  \begin{center}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0123-charge-200swp-rho-1.jpg.ps} \\
      \hspace{0.5cm}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0123-rho-1.jpg.ps} \\
      \hspace{0.5cm}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0123-rho5-1.jpg.ps}
      \caption{The scalar (middle) and pseudoscalar (bottom) density
        of the first non-zero mode for the $Q=-1$ configuration shown
        previously in Fig.~\ref{fig:zm.0123-rho-0}, along with the
        gluonic topological charge density after 200 sweeps of
        smearing (top). One sees how the scalar density extends over
        objects of differing charge, but that the regions of alternate
        charge are realized by the local chirality of the pseudoscalar
        density. In color online: negative density is blue/green,
        positive density is red/yellow (top), positive chirality is
        blue/green and negative chirality is red/yellow (bottom). In
        grey-scale: negative density dark, positive density light
        (top), and positive chirality dark, negative chirality light
        (bottom).}
    \label{fig:zm.0123-rho-1}
  \end{center}

\end{figure*}
One sees that the pseudoscalar density, according to its local
chirality, highlights certain parts of the topological lumps with
appropriate sign of charge, and leaves others (for other low-lying
modes).

The densities for the next two $Q=1$ and $Q=-1$ configurations are
shown in Figs.~\ref{fig:zm.0130-rho-1} and~\ref{fig:zm.0141-rho-1}.
\begin{figure*}[!h]

  \begin{center}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0130-charge-200swp-rho-1.jpg.ps} \\
      \hspace{0.5cm}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0130-rho-1.jpg.ps} \\
      \hspace{0.5cm}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0130-rho5-1.jpg.ps}
      \caption{The scalar (middle) and pseudoscalar (bottom) density
        of the first non-zero mode for the $Q=1$ configuration shown
        previously in Fig.~\ref{fig:zm.0130-rho-0}, along with the
        gluonic topological charge density after 200 sweeps of
        smearing (top). Again, the scalar density extends over objects
        of differing charge, and the regions of alternate charge are
        revealed by the local chirality of the pseudoscalar
        density. In color online: negative density is blue/green,
        positive density is red/yellow (top), positive chirality is
        blue/green and negative chirality is red/yellow (bottom). In
        grey-scale: negative density dark, positive density light
        (top), and positive chirality dark, negative chirality light
        (bottom).}
    \label{fig:zm.0130-rho-1}
    \end{center}

\end{figure*}
\begin{figure*}[!h]

  \begin{center}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0141-charge-200swp-rho-1.jpg.ps} \\
      \hspace{0.5cm}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0141-rho-1.jpg.ps} \\
      \hspace{0.5cm}
      \includegraphics[width=0.54\textwidth,angle=0]{zm.0141-rho5-1.jpg.ps}
      \caption{The scalar (middle) and pseudoscalar (bottom) density
        of the first non-zero mode for the $Q=-1$ configuration shown
        previously in Fig.~\ref{fig:zm.0141-rho-0}, along with the
        gluonic topological charge density after 200 sweeps of
        smearing (top). Again, the scalar density extends over objects
        of differing charge, and the regions of alternate charge are
        revealed by the local chirality of the pseudoscalar
        density. In color online: negative density is blue/green,
        positive density is red/yellow (top), positive chirality is
        blue/green and negative chirality is red/yellow (bottom). In
        grey-scale: negative density dark, positive density light
        (top), and positive chirality dark, negative chirality light
        (bottom).}
    \label{fig:zm.0141-rho-1}
  \end{center}

\end{figure*}
In the instanton model, a whole band of almost-zero modes is generated by
diagonalizing the Dirac operator in the field of a superposition of
$n_{+}$ instantons and $n_{-}$ anti-instantons
in the basis of linear combinations
of the $n_{+} + n_{-}$ zero modes corresponding to the case of infinite
diluteness. Apart from the remaining $|Q|$ zero modes, the almost-zero modes
are expected to bridge at least one pair of instanton and anti-instanton
with the scalar density peaking on top of the topological charge lumps and
the pseudoscalar density peaking with the appropriate sign there.
Qualitatively,
this is visible in Figs.~\ref{fig:zm.0123-rho-1},
\ref{fig:zm.0130-rho-1} and \ref{fig:zm.0141-rho-1}.

\section{Conclusions and outlook}
\label{sec:conclusions}
In this paper we have confronted the overlap-fermionic topological charge
density and the improved gluonic topological charge at different levels of
ultraviolet smoothing, realized in one case by a truncation of the mode expansion
at $\lambda_{cut}$ and in the other case by a certain number of smearing steps
applied to the gauge field in order to wipe out ultraviolet fluctuations.
These two views of getting the infrared topological structure of the gauge field
correspond to each other.
A similar result, however for APE smearing and a different improved Dirac
operator, has been found
in Ref.~\cite{Bruckmann:2006wf,Solbrig:2007nr}. In the present paper this has
been confirmed for two other specific realizations of both methods, using the
massless overlap Dirac operator~\cite{Neuberger:1998wv} on one hand
and stout-link smearing with respect to an over-improved Symanzik type
action~\cite{Moran:2007nc}
on the other. These two methods have their respective
advantages compared to the
approximate solution~\cite{Gattringer:2000js,Gattringer:2000qu} of the
Ginsparg-Wilson relation and APE smearing~\cite{Hasenfratz:1999ng}.

In this paper, the comparison has been
made more complete and detailed, based first on the density-density two-point
function and second on a point-by-point matching of the respective topological
densities.
The correspondence between the ultraviolet cutoff $\lambda_{cut}$ of
the overlap analysis and the number of smearing steps justifies the
use of over-improved stout-link smearing, which is computationally
less demanding, in the analysis of topological vacuum structure.
This is of particular interest when investigating the differences
between the vacuum structure of quenched and non-quenched
QCD~\cite{Moran:2007nc,Hasenfratz:1999ng}.

What we did not yet do in the present paper is the natural next step
of formulating
a description of the outstanding clusters of topological charge
(at each level of ultraviolet smoothing) in terms of an filtered field
strength, a possibility also offered by the overlap
analysis~\cite{Ilgenfritz:2007xu}. Furthermore, one should
study the degree of (anti)selfduality of
the gauge field and the percolation properties of the corresponding
(anti)selfdual domains~\cite{Ilgenfritz:2007xu}.
Both questions are accessible not only by the fermionic method but also by
the gluonic method based on stout-link smearing.

\section*{ACKNOWLEDGEMENTS}
E.-M.~I. acknowledges the support from DFG under the grant FOR 465 / Mu932/2-2.
E.-M.~I., K.~K., G.~S. and V.~W. thank T.~Streuer and Y.~Koma for collaboration
in earlier stages of the overlap project within this DFG-Forschergruppe.
E.-M.~I. thanks F.~Bruckmann, Ch.~Gattringer, M. M\"uller-Preussker, A.~Sch\"afer
and S.~Solbrig for collaboration on a similar comparative study within the
DFG-Forschergruppe.
He is grateful to Lorenz von Smekal for the invitation to Adelaide which was made
possible by a grant under the Strategic Research Scheme of the Faculty of Sciences
of the University of Adelaide devoted to the collaboration on Infrared QCD between
Humboldt University Berlin and Adelaide University.

P.~M. and D.~L. thank the Australian Partnership for Advanced Computing (APAC)
and the South Australian Partnership for Advanced Computing (SAPAC) for generous
grants of supercomputer time which have enabled this project. This work is
supported by the Australian Research Council.

redpajama_set_name: RedPajamaArXiv


text:
Ceratitis flexuosa is a species from the kingdom Animalia, family Tephritidae. This is a genus of Tephritid or fruit flies.

References

Dacinae
Agricultural pest insects

redpajama_set_name: RedPajamaWikipedia


Summer is right around the corner and as we make final preparations with our 2015 Summer Brides, we thought it would be the perfect time to reflect on one of our fave 2014 weddings, Gavin & Mica Mohrmann. With a unique style and vision, Gavin & Mica along with a talented vendor team, created a beautiful eclectic beach oasis to say "I Do". Surrounded with an intimate gathering of friends and family, the bride and groom celebrated in Cocoa Beach before moving to South Korea a few weeks after their nuptials. Chairs for Affairs provided our Bamboo Chairs, the perfect complement for the driftwood accents throughout the ceremony. Guests rejoiced along our 60″ rounds and danced the night away on our dance floor underneath our 30×40 tent. We are proud to have been featured on Green Wedding Shoes for our involvement with this unique celebration of love and new beginnings. Once again congratulations to the beautiful couple just a few weeks before their 1st anniversary!


The Oyster Cook-off Board, formally known as the Apalachicola Volunteer Fire Department Auxiliary, would like to congratulate two of the department's volunteer firefighters, Rhett Butler and Adam Joseph, on their receiving Fire Fighter 1 Certification in October.
Butler and Joseph attended 206 hours of firefighter training this summer through night classes and weekend training days, at the Eastpoint fire house, under the auspices of the late Brad Price, fire coordinator for Gulf County. Both Butler and Joseph fit these all-volunteer training hours around their full time jobs and families.
Thanks to the fundraising efforts of its annual Oyster Cook-off, the board was thrilled to be able to pay all the training costs for these two hard-working volunteers and as promised, purchased each one a full set of new bunker gear when they received their Fire Fighter 1 certification.
The purpose of the AVFD Auxiliary and the annual Oyster Cook-off fundraising event is to raise money for the city's volunteer fire department. Its top priority is to pay a portion of the fire truck payment and when Truck #1 was paid off three years early, the auxiliary was able to pledge assistance to the city for the new truck - Truck #3 - delivered in September.
The second priority is to pay for any training classes and certification for department's volunteers. If they can go, they will send them! And lastly, to provide safe, new equipment for the certified volunteer firefighters.
"We couldn't do this without the tremendous community support we've had over the past eight years of the Oyster Cook-off," said Shelly Shepard, board treasurer. "Thank you from the bottom of our hearts and we sure hope to see you again for the ninth annual Oyster Cook-off, on Saturday, Jan. 19, 2019.


Although Mississippi Valley-type (MVT) deposits have not been recognized in Mauritania there are permissive tracts for these deposits in the regionally extensive Proterozoic carbonate rocks of the Taoudeni Basin. Permissive tracts for undiscovered MVT Pb-Zn-Ag deposits in the Proterozoic carbonate units are supported by the occurrences of MVT mineral and alteration assemblages, presence of evaporites, proximity to major orogenic events that have produced MVT ores elsewhere, red bed sequences and basal aquifers that may have been potential brine migration pathways for large MVT hydrothermal systems.
Permissive tracts for SEDEX (sedimentary exhalative) deposits coincide with those for MVT deposits. However, the geodynamic setting of the Taoudeni Basin is unlike that of SEDEX ores elsewhere on Earth, and therefore the potential for this class of deposits must be rather low. SEDEX deposits occur along tectonically active, shale dominated passive margins or in intracontinental rift basins.


The Algemeiner reports: Israeli and Jewish American leaders are speaking out against New York University's (NYU) decision to host performances of a play that has been criticized for whitewashing Palestinian terrorism and demonstrating anti-Israel bias.
"The Siege," a production by a Palestinian theater company about a 2002 standoff between Israeli troops and armed terrorists at the Church of the Nativity in Bethlehem, will make its North American premier on Thursday at NYU's Skirball Center for the Performing Arts.
The five-week-long incident, part of Operation Defensive Shield, ensued after over 200 Palestinians — among them members of Fatah, Hamas, and Palestinian Islamic Jihad — fled from Israeli forces in Bethlehem and sought refuge in the revered Christian sanctuary, on the correct assumption that Israeli troops would not follow them inside. It concluded following complex international negotiations that resulted in the deportation of the wanted Palestinians to Europe and the Gaza Strip.


Tell your friends and neighbors about Sparkle! If they sign up for Sparkle's monthly service plan, you will receive a FREE MONTH of service!
If you want a sparkling clear pool, you need to clean your D.E. Filter.
D.E. filters, you should backwash when the pressure gauge reads 6-10 lbs. above normal.
Sand filters should be backwashed when the pressure reads 10-15 lbs. above normal.
D.E. (diatomaceous earth) pool filters do an amazing job of filtering your pool water so that your pool looks great, but only if they are clean. Inside of your filter are grids which capture small particles yet allow water to pass thru. As these grids get dirty, water flow is restricted and filtering action decreases. Also, if a grid has even a small tear in it, debris and D.E. powder will pass thru and end up in your pool. Individual grids can be replaced when cleaning. Backwashing flushes the grids and is critical, but taking apart the filter and doing a thorough cleaning is equally important. This should be done every 6-12 months.
Turn off the power to the pump (and make sure timer does not turn power on during cleaning), set system valves to prevent water flow to filter, open valve at top of filter to equalize pressure (and open drain valve at bottom of filter), remove metal band around center of filter and lift top off of filter (don't lift by pressure gauge), next rinse grids of large debris while still inside filter, then remove grid assembly from interior of filter, preferably disassemble and clean individual grids (spray grids with garden hose) and inspect grids for tears.
Replace any torn grids. Then reassemble grids and filter housing.
Clean O-ring between bottom and top of filter and lubricate O-ring with pool lubricant (not petroleum based) before putting top of filter back in place and completing reassembly. Remember to replace drain plug, and set valves to normal position when finished.
Finally, after restarting equipment immediately add D.E. powder.
Ever wonder why your pool isn't as clear as it used to be or the pressure is low? Typically your filter is dirty. The quickest way to increase pressure and clear up your pool is to backwash your filter. D.E. filters as well as sand filters need to be backwashed periodically for proper filtration.
First, turn off power to the pump, and then set your valve selector to backwash. Turn power back on and run for several minutes (some pools have a sight glass so that you can see when the water flowing becomes clear, indicating that backwash cycle is complete). Next, turn power off and set valve selector back to filter position, and then turn the power back on. This completes a backwash cycle. We recommend that you repeat this cycle several times. With sand filters, this completes the process. For D.E. filters, the final step is to now add D.E. (diatomaceous earth) powder to the closest skimmer to the filter. Your filter will have an information label showing its' size. Follow the guidelines on the D.E. powder bag for the amount of powder to add for your filter size.
Cartridge filters do not require backwashing, but do require periodic cleaning of the internal filter cartridge inside of the housing (monthly in the summer). With power off, release air pressure by opening the air release valve (next to the pressure gauge), then open the bottom drain of the filter to drain the water out of the filter. Next, take apart and open the filter housing and remove, then spray down the filter cartridges with a garden hose until clean. Then, replace the cartridges and reassemble the housing. Finally, close the drain valve, and turn the power back on (with air release valve still open). When water starts to spray out of air release valve, close the valve.
Excess loss of pool water dilutes your chemicals and increases your water bill.
Pools will lose up to 1-2 inches of water per week due to evaporation, backwashing and splash out, but if your water level drops more than that, you may have a leak. First check for obvious leaks near the equipment. Some equipment leaks can be fixed by replacing an inexpensive O-ring in the backwash valve unit. The "Bucket Test" allow you to compare your pool's water loss to the water loss in a bucket of water. Water loss due to evaporation will be the same for both.
Place a bucket of water on your pool step (with a rock in the bottom to weigh it down) and fill the bucket with pool water so that the level in the bucket is the same as the pool. Use a piece of tape to mark the water level in the bucket and another to mark the pool water level on the outside of the bucket. Check the levels after 24 hours. If the level of the pool water drops more, then a leak is indicated. This test can be done with the pump on and again with the pump off to help isolate the cause of the leak. If the pool water only drops while the equipment is on, this indicates a leak in the equipment or a pipe. A leak detection company can locate leaks in underground pipes. If the pool water drops when the equipment is off, then the leak may be from a crack, skimmer unit, light housing or drain. Skimmer leaks can occur when the skimmer unit separates from the concrete pool and can be repaired with epoxy for underwater use.
We can refer you to a leak specialist if needed.
Sadly, according to the Consumer Product Safety Commission, approximately 300 children under the age of 5 drown in backyard pools in the U.S. each year. Pool safety to prevent tragedy involves physically securing the pool from children. Access to the pool area from the house can be secured by door latches (above the reach of children), and by an alarm or chime on each door to the pool. Many home alarm systems have a chime feature that can be activated to let you know a door has been opened. Our battery powered door chime (featured product this month) can also alert you to an opened door. Additionally, fence gates should have a working latch. Products also exist that detect someone actually falling into the pool. The best security for your pool is a special fence that goes around the pool. Many of these are removable and are constructed of a strong mesh material. Protect-A Child pool fence company ( poolfencedallas ) is one of the companies that provide these fences and has an A+ rating with the Dallas Better Business Bureau. These fences can also have self-closing and self-latching gates for access to the pool. Even if you do not have young children, pool safety is an issue due to visitors with children, grandchildren staying with you, and the possibility of unsupervised neighborhood children entering your yard.


Here's a bird's-eye view of the Campbell River and Comox Valley hospital construction sites from mid-August. Our friends at SuavAir, based in Cumberland and Campbell River, have been taking video and still images of the two construction sites since May. For safety reasons, the videos were shot on a Sunday morning, when work on the sites below was at a minimum.
Earlier this year, the North Island Hospitals Project held a Design Development Celebration event to mark the completion of the design phase and to prepare for another important stage – the fit out phase.
More than 200 people attended the event in January, including staff from the North Island Hospitals Project, champions from our 30 clinical user groups, representatives from working groups such as the Aboriginal Working Group, and representatives from Tandem Health Partners.
The process of designing new hospitals in the Comox Valley and Campbell River took important steps forward in early May 2014 when the team from selected proponent Tandem Health Partners was introduced to Island Health user groups and advisory bodies.
More than 100 clinicians from Campbell River and the Comox Valley got to see Tandem's hospital design proposals and to meet with Tandem representatives in a day-long meeting at the Merville Hall May 5th.
Comox Valley Hospital – Flythrough from Island Health on Vimeo.
A blessing ceremony was performed by K'ómoks First Nation at the site of the new Comox Valley Hospital.
Work to prepare the new Comox Valley Hospital site for construction of a $334 million 153-bed facility should be underway by late February. Island Health's North Island Hospitals Project team is working with the neighbours to make sure the project gets off to a good start.


In the last 20 years we did over 350 projects. From small to large, fom short-term to longer running projects. And this number is still increasing!
We work global. We have done projects in the Netherlands, the UK, the USA, Belgium, Australia and more. And some of these projects are ongoing.
We served more than 200 customers. In the Netherlands and in other countries.
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With a lot of knowledge and over 20 years of experience, we are specialized in customised solutions in Microsoft Office and .NET settings - Business Applications and Customization & Integration Solutions - working together on a variety of software systems.
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Nice to contribute to the DNA of Schuberg Philis!
Schuberg Philis , a good customer for years, has asked Flores.nl to adapt a large number of Microsoft Office custom applications and templates to the restyling, the new house style of Schuberg Philis.
Flores.nl has developed IATI Insights , a Microsoft Power BI tool, with which IATI files your organisation's IATI files turns into a beautiful and insightful dashboard (see demo). It provides insights into the financial situation of projects on the desired indicators and you don't have to do anything you're not doing already.
Together with Flores.nl Plan Netherlands has developed an IATI Project Management System, by means IATI data to be used as management information.
Plan Netherlands has presented this 22 March at the IATI LEARNING EVENT in The Hague. The system has been well received.
Mitchel Hoedt and Niels de Boer both passed their C# exam today.
Flores.nl has been offering various IT services in the Higher Education sector for many years now, for example, in the areas of student recruitment and alumni relations. Since 2016 we have expanded our range of services with support in the field of Learning Management Systems, namely, Brightspace from the company D2L.
Flores.nl is the first organization in the Netherlands that specializes in Brightspace. Meanwhile, more universities and colleges have shown serious interest and we are expanding the team with certified trainers and advisors who can support educational institutions with Brightspace projects.
Technical University Delft is the first Dutch university that uses Brightspace. Over 22.000 students and 5000 staff members will use D2L's Learning Management System (LMS). On D2L's recommendation Flores.nl will support the implementation of Brightspace. Our consultant Kristiaan Hillen will help out the project team and the system admins with knowledge of and experience with Brightspace.
RightBrains is the platform for talented women with a passion for IT and wants to inspire, connect and develop. The website plays a crucial role in this.
Flores.nl is honored that we are allowed to build new website for RightBrains and also contribute to the beautiful platform.


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HomeThe Dead Don't Lie
The Dead Don't Lie
by Karen Treiger
Image by Courtesy Karen Treiger
We visited the dead in Stoczek. The dead don't lie.
Stoczek is the Shtetl where Esther was born and the place from which Sam was taken to the Death Camp Treblinka. There are enough ghosts here to compete with Hogwarts.
Grzegorz Maleszewski took us to Stoczek. Our first stop was the vacant lot that once was the Kwiatek soda factory. Just to the right of the empty lot stood a pre-war home. This, we were told, was a typical house. I imagine 74 years ago it looked better, but still…
Then we visited the Christian dead. At the cemetery we paid our respects to Helena and Aleksander Stys, Wladyslawa and Stanislaw Stys, Edward Stys, Elzbieta and Waclaw Maleszewski (Grzegorz's parents) and others who knew Esther and Sam and were involved in their lives and survival. I was humbled. Would I have had the courage to help when so many others did not. I hope so, but I am blessed to never have been put to this test.
The Stoczek Christian cemetery is beautifully kept and well-manicured. Colorful flowers adorn the graves. The tombstones are clean and the writing clear. The small red brick chapel in the center stands cheery and solid, with a steeple reaching up to the heaven. The Christian dead told us that they were honored and respected and have been well cared for. Their ghosts are at peace.
Then we visited the Jewish dead. This was an altogether different experience. The Stoczek Jewish cemetery is no more. No tombstones, no flowers, no chapel. It is overgrown with weeds and littered with garbage. Under the earth – in this place – are the Jews of Stoczek who died before September, 1939, who had the zechus (merit) to be properly buried.
During and after the war, Poles took Jewish tombstones for building material – to build walls or streets. A number of years ago, the town finally gathered the small number of broken and faded tombstones that remained and placed them next to the cemetery where they had erected a memorial to the murdered Jews.
Jan Stys, a man full of life at 87, an eyewitness, told us how he was an 11-year old school boy, sitting in his classroom looking out the window. The window looked out over the Jewish cemetery. Jan watched that August day of 1942, as the Nazis shot and killed his Jewish neighbors. He understood that this war was not nice.
Who knows why some were murdered here and others taken to Treblinka. Perhaps it was the old and disabled who would have had trouble making the trek to the gas chambers. Perhaps it was Nazi sport. No way to know.
The Jewish dead told us that they have been dishonored and abused. Their ghosts are not at peace. They are eternally crying for themselves and for their murdered children and grandchildren.
תנצב"ה -May their souls be bound up in the bond of eternal life.
The views and opinions expressed in this article are the author's own and do not necessarily reflect those of the Forward.
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This blog is dedicated to bringing World War II era documents to the general public, with an overall focus on armoured warfare. Questions? Requests? Comments? Email me at tankarchives@gmail.com or find me on Twitter @Tank_Archives.
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Western Allies and Other Nations
Germany and Other Axis
Archive Sources
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SPG #212: Pillbox Hunter
The war between the USSR and Finland that broke out on November 30th, 1939, revealed a ton of deficiencies in the organization and management of the Red Army. Naturally, questions regarding materiel also arose. It was finally clear that the Red Army needs tanks that can withstand cannons. The need for a specialized SPG that could destroy fortifications was also obvious. The KV-2 was one such vehicle, and even had time to fight the Finns, but it was destined to be replaced by the 212 SPG with an even more powerful gun.
Two Meters of Concrete
The KV-2 had many advantages compared to analogous SPGs that were designed at factory #185 to fill the same niche. For one, the KV-2 was built on the chassis of the KV-1, which was already accepted for service, the only difference being in the turret and the gun. Factory #185 was designing vehicles on the SU-14 and T-100 chassis. The SU-14 was abandoned in 1938, and the future of the T-100 was under question. The KV-2 was also smaller than its competitors, and had thicker armour.
The KV-2 also had plenty of drawbacks from the point of view of the artillerymen. In order to fit the 152 mm M-10 howitzer into the KV-2's turret, it had to be shortened, reducing its already humble concrete piecing effects. The ability to penetrate 90 mm of armour from a kilometer away was not enough when dealing with bunkers like the Finnish "millionaire". The KV-2 was not a replacement for factory #212's SPGs, but a supplement.
152 mm mod. 1935 gun, the best method of destroying pillboxes.
A proposal clarifying tank armament dated June of 1940 listed "self propelled heavy artillery for destruction of pillboxes" as point #3. The SMK heavy tank was suggested as the chassis, armed with a 122, 130, 152, or 180 mm gun. The most promising candidate was the 152 mm mod. 1935 gun, or the Br-2. The production of the T-100Y with a 152 mm Br-2 gun was suggested as a temporary measure, but there was no time to mount the guns on either the SMK or the T-100; in July the projects were cancelled. Only one of the suggestions from the proposal document was produced, namely the production of the "KV tank with a large turret". As it often happens, the temporary measure became permanent.
The fixation on the Br-2 was no accident. Factory #185 picked the 130 mm B-13 gun. It could penetrate 130 mm of armour at a range of almost 4.5 km. There was a problem with the quality of shells, but that could be observed with any Soviet ammunition of that time period. It seemed that the B-13 was enough to combat fortifications, but the artillerymen had their own idea.s Even though the fate of the Br-2 was a difficult one and the production volumes were miserly even compared to the B-4 high powered 203 mm howitzer, the gun had fantastic characteristics. It could penetrate that same 130 mm of armour at 5 kilometers, and calculations showed that a concrete penetrating shell from the Br-2 could penetrate a 2 meter thick concrete wall. That was the thickness of the walls of the bunkers on the Mannerheim Line. The presence of a "can opener" like this on a self propelled chassis could effectively solve the problem of well prepared echeloned defenses.
The T-220 heavy tank became the prospective chassis for the heavy tank destroyer after the T-100 and SMK were cancelled.
After the T-100 and SMK were cancelled, the bunker buster issue didn't go away. On July 17th, 1940, decree #1288-495ss was issued by the Council of Commissars, which ordered the Kirov factory to build 4 modernized KV tanks by December 1st, 1940. Two of them had 100 mm of armour, two had 90 mm. The armament was also different. A fifth vehicle was mentioned in the document which would have become the chassis for the 152 mm Br-2 gun.
The Kirov factory assigned the index "212" to the bunker buster project. The SPG is also called "object 212" in correspondence, but that is not an official title. There was also a second vehicle with that index, an engineering vehicle on the KV chassis that never passed the full sized model stage. The index "212A" is used in some sources, but it was not present in factory documentation. The 212 project was led by Zh.Ya. Kotin, and Ts.N. Golburt was the senior engineer on the project.
212 SPG, cutaway.
2 million rubles were allotted to the 212 project. According to the Kirov factory budget, 100,000 was spent on the design project, 25,000 on the model, 300,000 on blueprints, 75,000 on blueprint editing, 1,100,000 on production of the prototype, 100,000 on trials, and 300,000 on repairs. This budget did not include the cost of a gun.
The project was not a priority at SKB-4. Their main task was the creation of heavy tanks with more powerful armour and armament. Real work on the 212 project only began in August of 1940, after receiving tactical-technical specifications, and work on blueprints did not start until October. This was fully connected with the T-220 tank, which served as the chassis for the SPG. In October, the SPG began to take shape.
The 212's hull blueprints were finally approved by Kotin on November 5th, 1940. Note that there was no room for a hull gunner/radio operator.
Externally, the 212 resembled the enclosed version of the SU-14. The fighting compartment was in the rear, the engine compartment was in the center, the driver's compartment up front. There was only room for the driver in that compartment, shifted to the left. Some renders of the vehicle show a machinegun in the front plate, like on the KV It would have been difficult for the radio operator to fire it with the crankshaft passing through his spine.
Even through the resulting SPG was rather large, it seemed a lot smaller when compared to its predecessors, especially the SU-14. The rear casemate seems enormous, but in reality it was less than half a meter longer than the T-220 and a little bit taller. With such a large gun, it would not have been possible to make the casemate smaller. The V-2SN 850 hp engine, created by combining the V-2 with the AM-38 aircraft engine's mechanical supercharger, was proposed as the power plant. The same engine would go into the T-220.
Hull of the 212.
The requirements given by the Artillery Committee caused fierce debates in December of 1940. Due to the late requirements and high priority of the T-220, the Kirov Factory could not present the 212 by December 1st. However, on December 10th, a letter from the Kirov factory was sent to the Artillery Committee, signed by Kotin, Fedorov, and Golburt. The letter contained many complaints about the requirements. The problem was that the required 75 mm of armour were completely incompatible with the maximum weight of 55 tons. This was not a problem with only the SPG. The T-220's mass started out at 56 tons and ended up being 62.7 tons.
The 212 was even larger. Rough calculations showed that with a mass of 55 tons, only 17.5 tons were left for the hull. The SMK, which was close in size but had thinner armour, had a 31 ton hull. The solution was simple: lift the weight limit to 65 tons. Even with this limit, the front armour had to be reduced to 60 mm.
After debates that lasted until the end of December, the artillerymen were forced to give in. According to a GABTU report on experimental work, the Kirov factory completed a series of components for the 212 by January of 1941. The design project was also completed, and blueprints were sent to the Izhor factory to build the hull. 1.5 million rubles were spent on the 212 by that point. According to a report from the Kirov factory, a full set of hull parts arrived from the Izhor factory on March 5th. Assembly was delayed due to a shortage of parts produced by the Kirov factory. This is where work stopped, as after March, the factory was too busy for a bunker buster.
Victim of a Phantom Menace
On March 11th, 1941, the General Staff received a report on the status of the German tank industry. Among other things, the report listed the production of new heavy tanks, the largest of which weighed 90 tons. The report radically changed all plans regarding heavy tanks. Instead of the T-150, set to be released under the index KV-3, requirements for a new tank indexed 223 were drawn up. Work on even heavier KV-4 and KV-5 tanks also began. All of these projects had a higher priority than the bunker buster. No progress was observed in May or April of 1941.
Supercharged V-2SN engine, the heart of the T-220 and KV-3.
This pause didn't mean that the bunker buster was cancelled. In April of 1941, new targets were thought up for the 212, the same heavy tanks that Soviet intelligence described. Guns other than the 152 mm Br-2 were considered for the role, described in Marshal Kulik's letter to Stalin, sent on April 17th, 1941.
"Create SPGs to fight bunkers and superheavy tanks using the following heavy artillery systems: 152 mm Br-2 gun, 130 mm B-13 gun, and the new powerful 107 mm gun. The 152 mm Br-2 gun can penetrate 155 mm of armour at 0 degrees from 2300 meters, the 130 mm gun penetrates 130 mm at 0 degrees from 4000 meters, the new 107 mm gun will penetrate 160 mm of armour at 30 degrees at 1000 meters.
The 152 mm SPG is already designed, and a prototype is being assembled at the Kirov factory. A lengthened KV-4 chassis is used. The mass of the SPG with a 152 mm gun is 65 tons. The SPG is protected by 60 mm of armour. Council of Commissars decree #274-120 issued on February 7th, 1941, tasks the Kirov factory with the production of 10 SPGs with 152 mm Br-2 guns this year.
It is necessary to instruct the NKTP to provide the pilot prototype on June 1st, 1941, and ensure that the rest of the SPGs are built during this year. Also instruct the NKTP to produce an experimental 130 mm SPG by September 1st and a 107 mm SPG by October 1st. The chassis will be the same as on the 152 mm SPG. The factory already has a 130 mm B-13 gun. Instruct the NKV to produce a 107 mm gun at factory #172 and send it to the Kirov factory by July 1st, 1941."
A vehicle armed with the 130 mm B-13 naval gun appears several times in GAU and GABTU correspondence. According to requirements dated June 16th, 1941, the mass of the vehicles had to be 55 tons. Unlike the 212, the SU-B-13 was not a bunker buster. The requirements are for a heavy tank destroyer, which was hurriedly developed to fight German heavy and superheavy tanks. Its armour was only 30 mm thick, and the description "the gun is mounted without a turret, on the stock mount with necessary protection on top from diving aircraft" suggests that the SU-B-13 and 212 would have been significantly different. It's more likely that the result would have been an analogue of the German "self propelled gun mounts", like the 12,8 cm Selbstfahrlafette auf VK3001(H), which was designed in May of 1941, likely also as a means against Soviet superheavy tanks.
As for the 107 mm SPG, it didn't move past the proposal stage. No tactical-technical requirements were created. The armament would be the 107 mm ZiS-24 or the M-75. Grabin's gun was never built, but the M-75 was not only built, but tested.
107 mm M-75 anti-tank gun, one of the two candidates for the heavy tank destroyer.
Work on a lighter SPG didn't mean that the 212 was done for. Decree of the Council of Commissars issued on May 27th, 1941, illustrates that the artillerymen didn't give up on the bunker buster. It is listed in the first paragraph, but with a KV-3 chassis. Since both the 212 and the KV-3 were based on the T-220, nothing really changed. The first vehicle was due in August of 1941. The initial order was for 12 vehicles, later reduced to 10.
Without a Chassis
Some authors write that the 212 was cancelled after the start of the Great Patriotic War, but that is not so. In reality, the start of the war only suspended the work on the vehicle which hasn't seen any progress since March anyway. The bunker buster project was attached to the Kirov factory until August. An attempt to cancel it caused a furious letter from deputy chief of the GAU, Colonel-General Hohlov.
The project was only transferred to the Ural Heavy Machinebuilding Factory (UZTM) in late August of 1941. The factory had a wealth of experience building artillery systems. In 1941, the factory also became ChTZ's contractor for KV-1 hulls and turrets. The factory's design bureau was headed by F.F. Petrov, who developed many artillery systems, including heavy ones. However, neither the factory nor its design bureau had any experience with designing tracked vehicles.
Factory diagram of the 212, side view.
In early October of 1941, GAU received a letter from the chief engineer of UZTM, A.S. Ryzhikov. Ryzhikov requested all available information on the KV-3 and armament that was meant for the SPG. After that, activity on the bunker buster project died down for a while. The KV-3 chassis meant for the project was absent, and ChTZ, tasked with producing the tank, had better things to do in August of 1941. In addition, GAU's Artillery Committee was in no hurry on the bunker buster issue. All of these factors contributed to work being stuck. The topic of bunker busters arose once more in November of 1941. The issue was very interesting: due to factory evacuations and lifting of cancellation of the artillery tractor order at ChTZ, production of tractors ceased completely. There was a chance that soon, nothing will remain to tow artillery. A whole family of SPGs in the plan for 1942 was the solution. The first in the list was a 152 mm Br-2 gun on the KV chassis.
Reconstruction of the SPG's exterior.
In March of 1942, the subject of a 152 mm bunker buster on the KV chassis arises again. The chassis was from the KV tank, the gun was the oscillating part of the Br-2. The experimental factory #100, organized in March, was responsible for the chassis. Factory #8 was responsible for the gun. 1.5 million rubles were allocated to the project, and a prototype was due by July 1st. However, by the spring of 1942, the KV-3 was finally dead and another vehicle was explored as a chassis for a bunker buster.
The 212 never progressed past the construction of the hull, which was never fully assembled. Even if it was built, it's unlikely that its fate would have been a good one. The project was tied to production of the Br-2 gun, which stopped in 1940. Even the preliminary production volume was only 12 units, and the price of each vehicle was about a million rubles. The heavy bunker buster was a dead end branch in the Soviet heavy SPG tree.
Original article by Yuri Pasholok.
Labels: B-13, Br-2, KV-2, Object 212, penetration, pre-war, prototype, time and money
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Tanks that could have been built are often discussed within certain circles. Aside from the superheavy Maus and E-100 , there are the ligh...
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The Dallas Cowboys have released 10-year veteran cornerback Orlando Scandrick [url=http://www.ravenscheapstores.com/patrick-onwuasor-jersey-cheap]Patrick Onwuasor Jersey[/url] , another move toward getting younger in the secondary.
Scandrick had asked for a release that the Cowboys made official with Saturday's move. The post-June 1 designation gives Dallas $3 million in salary cap space this season with a $1.6 million cap charge in 2019.
The 31-year-old Scandrick was a fifth-round pick by the Cowboys in 2008 and had eight interceptions in 125 games. He missed all of 2015 after tearing ligaments in his right knee late in training camp and struggled with injuries the past two seasons.
Dallas drafted cornerbacks Chidobe Awuzie and Jourdan Lewis in the second and third rounds last year. The Cowboys are moving 2015 first-round pick Byron Jones back to cornerback from safety and have other young defensive backs as well.
Giants closer Hunter Strickland broke his pitching hand punching a door in frustration after blowing the save and taking the loss in a 5-4 defeat to the Miami Marlins on Monday night.
The right-hander had surgery Tuesday and expected to be out six to eight weeks, manager Bruce Bochy said. An X-ray after the game revealed the break of Strickland's pinkie, similar to what sidelined lefty ace Madison Bumgarner to begin the season after he was hurt in his final spring training start.
Strickland blew his fourth save in 17 chances and second straight [url=http://www.raiderscheapstore.com/tahir-whitehead-jersey-cheap]Tahir Whitehead Jersey[/url] , allowing more than two runs for only the fourth time in his career.
He posted an apology on Instagram and Twitter.
Bochy said Strickland had shown maturity and made progress keeping his emotions in check since last year's fight with Nationals star Bryce Harper.
In late May last year, Strickland ignited an all-out brawl when he beaned Harper with a 98 mph fastball on his first pitch in the eighth inning with two outs, none on and Washington ahead 2-0. Harper charged the mound and both men threw punches as benches and bullpens emptied.
Sam Dyson and Tony Watson will be called upon for closing duties, with one getting most of the opportunities though Bochy didn't reveal which one that would be. The manager doesn't consider Mark Melancon – signed to a $62 million, four-year deal before last season to work the ninth – ready for the role after a series of injuries.
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Right-hander Pierce Johnson was on his way from Triple-A Sacramento to take Strickland's roster spot.