Difference between heartwood and sapwood
Forest Products Laboratory (U.S.)
1919
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27 records were found.
In this dissertation it was performed the improvement of an automatic calculation program about consolidation, that was developed many years ago at University of Minho, making it more friendly to the user, mainly for pedagogical purposes.
For this purpose, two graphical interfaces were created in MatLab, one being for data input and another for output of results. The first allows both a basic introduction of data, where many of the input parameters are assumed by default, and a complete introduction of data where the user has to enter all the data. The second allows that the results obtained may be displayed using graphics, many of which are presented in a dynamic manner, with the output parameters varying over time. With the new improvements there are multiple options related to the results output.
This dissertation also presents tw...
MATLAB (short for Matrix Laboratory) was created by Cleve Moler and Jack Little in the
1970’s. It is a programming language for technical computing. Its environment is easy to work
with, the syntax is very simple and intuitive, it has powerful toolboxes to treat many different
problems in engineering, and it allows us to produce fantastic graphics as the programme
runs. It also allows us to create a graphical interface (via graphical user interfaces - GUIs) that
gives our programme a look that is very close to professional software.
Because of many of the mentioned features, a MATLAB code can be very compact, allowing
anyone to have "the big picture" of any code without have to look at all its details. Another
great advantage of Matlab is that, if the code is written in a vectorized form, the code can
run much faster than if it was wri...
In this paper we discuss a novel accurate method for
computing transonic flow over lifting and non-lifting aerofoils as
governed by the steady K´arman-Guderlay equation. The method
is based on using finite-differences in the streamwise direction
combined with spectral collocation in the other direction. This
is combined with Newton iteration and a direct method for the
resulting linear system. The method is fast and very robust and
we are able to compute steady flows with strong shocks. Some
examples considering both the symmetric and the non symmetric
cases are shown and grid size study is also presented. The work
has been extended to discuss the stability of the computed flows
using methods based on a global stability analysis. This leads to a
generalized eigenvalue problem and some results are presented.
One advantage of the current...
In this paper we discuss a novel accurate method for computing transonic flow over lifting and non-lifting
aerofoils as governed by the steady K´arman-Guderlay equation. The method is based on using finite-differences in
the streamwise direction combined with spectral collocation in the other direction. This is combined with Newton
iteration and a direct method for the resulting linear system. The method is fast and very robust and we are able
to compute steady flows with strong shocks. The work has been extended to discuss the stability of the computed
flows using methods based on a global stability analysis. This leads to generalized eigenvalue problem. Some
preliminary results are presented. One advantage of the current approach is that for small grid sizes it is possible
do the analysis using MATLAB.
It is shown that quantitative information on spatial correlations in a system of
polarizable particles can be extracted directly from its experimentally measurable optical spectra.
For a collection of metallic nanoparticles (NPs), it is demonstrated that the degree of shortrange
correlation in NP’s positions can be evaluated by an appropriate numerical analysis of
the extinction spectrum in the surface plasmon resonance region, given the polarizability of an
individual NP. The spectrum analysis consists in the evaluation of a single number, which is
the derivative of the ensemble response function in the vanishing polarizability limit, using the
Tikhonov regularization method. This number has to be compared to pre-calculated values for a
model NP system with given density and correlation parameters.
This paper intends to show how easy it can be to build a prototype that will help water resources managers to make their decisions not only based on politics or economics, but also with a scientific tool that will help them build different weather scenarios. First we present a very simple mathematical model that has all the potential to evolve from version to version. Its implementation is easy to do, using a platform to perform simulations, called Vensim PLE. The philosophy that Vensim PLE follows to build up models of simulation is very interesting and simple.
It is based in 3 main entities - container variables, auxiliary variables and fluxes. It is a pictorial based language, and therefore, it is quite easy to follow models. The details are hidden when you define these entities represented in a figure. We used a freeware version fo...
The 2D Stokes problem for incompressible fluid involves condition ∇.U = 0
augmented with the constraint that the pressure average over domain
is fixed to guar-
antee the uniqueness of the solution.
We propose a new mathematical formulation for the Stokes problem and a new finite
volume scheme where we guarantee both incompressibility and the null mean pressure con-
straint in the same equation.
This paper presents a theoretical analysis of perfect gas flow over a convex corner
of a rigid-body contour. It is assumed that the flow is subsonic before the corner. It
accelerates around the corner to become supersonic, and then undergoes an additional
acceleration in the expansion Prandtl–Meyer fan that forms in the supersonic part
of the flow behind the corner. The entire process is described by a self-similar
solution of the K´arm´an–Guderley equation. The latter shows that the boundary
layer approaching the apex of the corner is exposed to a singular pressure gradient,
dp/dx ∼ (−x)−3/5, where x denotes the coordinate measured along the body surface
from the corner apex. Under these conditions, the solution for the boundary layer also
develops a singularity. In particular, the longitudinal velocity near the body surface
behaves a...
The 2007 report of the Intergovernmental Panel on Climate Change (IPCC)
projected with high confidence that the conditions (drought and high
temperatures) in the Southern Europe will worsen. It stated that this region that
includes Portugal is already vulnerable and will experience a reduction in water
availability, hydropower potential and crop yield and productivity. The evidence
of such conditions have already struck Portugal when during the 2004-2005
hydrological year experienced one of its worst droughts in decades. Between
June to September 2005, the whole country was classified as experiencing
sever to extreme drought according to the Palmer Drought Severity Index
(PDSI). At the same time, Portugal was developing its new Water Law based on
the requirements of the so called Water Framework Directive of the Eur...
This paper intends to show how easy it can be to build a prototype that will help water resources managers
to make their decisions not only based on politics or economics, but also with a scientific tool that will help
them easily build different weather scenarios. First we present a very simple mathematical model, that has all the
potential to evolve from version to version. Its implementation was in Vensim PLE. Vensim PLE is a very easy and
intuitive tool to perform simulations, being the philosophy that Vensim PLE follows to build up models of simulation
very interesting and simple. It is a visual programming language based in three main entities ??? container
variables, auxiliary variables, and fluxes. The details are hidden when you define these entities represented in a
figure. In this paper we used a freeware version for ...
