ENGINEERING TRANSACTIONS
ROZPRAWY INŻYNIERSKIE
A QUARTERLY JOURNAL
- A. Ercolano:
Exact representation of the derivatives of isotropic tensor functions
with respect to the deformation gradient F
- M.A.M. Abdeen, A.E. Abdin:
Effect of subsurface heterogeneous correlated hydraulic properties on the
stochastic behavior of the unsteady well drawdown in a confined aquifer
- M. Cieszko, M. Kempiński:
Determination of limit pore size distributions of porous materials from
mercury intrusion curves
- J. Guzik, M. Wojtyniak, S. Olszowski, M. Marczak, Z. Ranachowski:
Investigation of acoustic emission signal generated in the friction pair lubricated
with oils containing various lubricity additives
- A. Ercolano:
Exact representation of the derivatives of isotropic tensor
functions with respect to the deformation gradient F
- Expressions for derivatives of isotropic tensor functions with respect to
the deformation tensor F are derived. Each derivative has the first
representation in terms of eigenvectors; then, for computational conveniences,
also a basis-free expression, in terms of eigenprojections, is reported. Further,
in the same fashion, also the time derivatives are provided. In the paper, a short
review of different approaches to the problem existing in literature is presented.
In order to make the exposition self-contained, some backgrounds of tensor analysis
are also given.
Contents
- M.A.M. Abdeen, A.E. Abdin:
Effect of subsurface heterogeneous correlated hydraulic properties on the
stochastic behavior of the unsteady well drawdown in a confined aquifer
- Groundwater is considered to be one of the most important water resources especially in
areas where surface water resource, is not sufficient. However, utilizing this important
groundwater resource requires a complete understanding of the groundwater flow behavior
within the subsurface formations. The assumption of considering the subsurface formation
as homogeneous media has been proven to be un-realistic. Therefore, the subsurface formation
has to be considered as a heterogeneous structure in investigating the groundwater flow
behavior. In addition, full understanding of the impact of the subsurface heterogeneous
formation on the groundwater flow behavior is very essential in safe utilization of this
important water resource.
- The current study investigates the impact of two subsurface heterogeneous correlated
hydraulic properties on the stochastic behavior of a two-dimensional unsteady well drawdown
in a confined aquifer. In addition, the presented study compares the impact of two subsurface
heterogeneous cases. The first case considers two subsurface correlated hydraulic properties
(current study), while the second case considers the heterogeneous subsurface hydraulic
conductivity only. The two hydraulic properties considered in the current study are the
subsurface hydraulic conductivity and storativity. The Monte Carlo stochastic approach is
used in this study to perform various numerical computations required to assess the
investigated problem. The results obtained from this study showed how important it was
to consider and understand the heterogeneous subsurface formation and its impact on the
groundwater flow behavior, since the two-dimensional unsteady well draw-down was greatly
affected by the degree of heterogeneity and the correlation structure of the subsurface
hydraulic properties.
Contents
- M. Cieszko, M. Kempiński:
Determination of limit pore size distributions of porous materials
from mercury intrusion curves
- The application of the capillary and chain models of pore architecture are
proposed in the paper for determination of limit pore size distributions of
porous materials based on the mercury intrusion curves. They estimate the range
of pore sizes in the investigated material. It is proved that for a given pore
size distribution, the capillary model of pore architecture, commonly used in
the mercury porosimetry, and its chain model, are two limit cases of the network
model of pore architecture, considered in the paper as a proper model for most
real porous materials. For both limit pore architectures, the expressions describing
capillary potential curves have been derived that are the basis for the procedure of
determination of two limit pore size distributions. This procedure has been illustrated
by determining the limit distributions for porous materials made of sintered glass beads.
Contents
- J. Guzik, M. Wojtyniak, S. Olszowski, M. Marczak,
Z. Ranachowski:
Investigation of acoustic emission signal generated in the friction pair
lubricated with oils containing various lubricity additives
- The energy supplied to the friction pair is dissipated producing
mainly heat. However, a small part of it radiates in the form of transient elastic
waves or in other words, as the acoustic emission (AE) signal. This article presents
measurement results of the AE signal generated in the four-ball friction pair lubricated
with oil containing chosen lubricity additives. Measurements of the AE signal have been
performed in conditions of continuous load increase. Values of friction torque in the
pair were recorded simultaneously with AE measurements. It is expected that diagnostic
measurements of AE signal generated in friction pairs of working machinery will be possible soon.
Contents
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