buletinul institutului politehnic din iaşi bulletin of the polytechnic ...

BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI
BULLETIN OF THE POLYTECHNIC INSTITUTE OF IAŞI
Publicat de
UNIVERSITATEA TEHNICĂ „GHEORGHE ASACHI” DIN IAŞI
Tomul LV(LIX), Fasc. 1 2009
Section
MATHEMATICS. THEORETICAL MECHANICS. PHYSICS
C O N T E N T S
Pp.
AZIZ ULLAN AWAN (Pakistan), CORINA FETECĂU and MUHA-MMAD
IMRAN (Pakistan), Some Exact Solutions for a Generalized Oldroyd-B Fluid
Between two Side Walls Perpendicular to a Plate (English, romanian
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
WASEEM AKHTAR (Pakistan) and MUHAMMAD JAMIL (Pakistan), On the
Axial Couette Flow of a Maxwell Fluid due to a Longitudinal Time
Dependent Shear Stress (English, Romanian summary). . . . . . . . . . . . . . . . . . 11
IMRAN SIDDIQUE (Pakistan) and QAMMAR RUBBAB (Pakistan), New Exact
Solutions Corresponding to Stokes’ Second Problem for Maxwell Fluids
(English, Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
GHEORGHE ZET, Self-dual Gauge Fields on Non-commutative Space-Time
(English, Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
CAMELIA POPA and DOINA PARTENIE, Self-Dual SU(2) Gauge Theory over
a 4-D Space-Time with Spherical Metric (English, Romanian summary). . . . . 39
MARINA-AURA DARIESCU, CIPRIAN DARIESCU and ANA CAMELIA
PÎRGHIE, Fermions on 5D Warp of Einstein Universe (English, Romanian
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
CRISTINA STAN, CONSTANTIN P. CRISTESCU and BOGDAN MEREU,
Observation of a Torus Doubling Evolution to Chaos in an RLC Circuit with
MFS Capacitor as Nonlinear Element (English, Romanian summary) . . . . . . . 53
VIOREL STANCU and LIVIU BĂDELIłĂ, Simulating and Modeling
Turbulence and Chaos in Fusion Plasmas Using Logistic Map (English,
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
OANA NICULESCU and CRISTINA-DELIA NECHIFOR, On the Effects of
Low Pressure Argon Plasma Treatment on PVA Films (English, Romanian
summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

VALERIU DAVID and MARIANA LATU, Electromagnetic Properties of Chiral
Metamaterials (English, Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . .
RODICA BĂDESCU, VASILE BĂDESCU and GABRIELA APREOTE-SEI,
Propagation Velocity and Attenuation Coefficient of an Ultra-sound Wave in
a Ferrofluid (English, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . .
GABRIELA CĂLIN, FELICIA CARMEN DASCĂLU, ADINA CO-ROABĂ,
FLORIN BRÎNZĂ and NICOLAE SULIłANU, Discreet Nanostructures of
Pb, Sn, Cu, Ni by Arc-discharge Synthetized (English, Romanian summary).
MIHAI LOZOVAN, HORIA CHIRIAC, VIOREL DOBREA, MIHAIL-LIVIU
CRAUS and SERGIU MOHORIANU, Gal-vanomagnetic Effects of New
CoFeSiBMo Alloy (English, Romanian summary) . . . . . . . . . . . . . . . . . . . .
CORNELIU STAN, MARIUS SEBASTIAN SECULA, DANA TUTULEA,
DOINA SIBIESCU, IOAN ROŞCA and IGOR CREłESCU, Core Shell
Phosphorescent Composites Applied in Optoelectronics(English, Romanian
summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GEORGIANA BOLAT, ADRIAN CĂILEAN, DANIEL SUTIMAN and
DANIEL MARECI, Thermodynamic Properties of (Toluene + An Alkane) at
298.15 K (English Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CRISTINA-DELIA NECHIFOR, ECATERINA ANGHELUłĂ and DANA-
ORTANSA DOROHOI, Visible Birefringence of PVA Thin Foils (English,
Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MONICA R. NEMłANU and MIRELA BRAŞOVEANU, Effects of Electron
Beam Irradiation on Aqueous Solution of Corn Starch (English, Romanian
summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DANIEL TOACĂ, IOSIF BARTHA, RODICA MARIA NEAGU and NICOLAE
MARCOI, The Geoelectrical – Rheoelectrical Method for the Management
of Underground Water (English, Romanian summary) . . . . . . . . . . . . . . . . . . .
VASILE BĂDESCU, LAURA-ELENA UDREA, OVIDIU ROTARIU,
RODICA BĂDESCU and GABRIELA APREOTESEI, An Analysis of a
High Gradient Magnetic Separator for Extracorporeal Blood Purification
(English, Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
LAURA-ELENA UDREA, VASILE BĂDESCU, OVIDIU ROTARIU, RODICA
BĂDESCU and GABRIELA APREOTESEI, Some Features of Electric and
Magnetic Separation of Nanospheres from a Simulated Biological Fluid
(English, Romanian summary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
CRISTIAN GOICEANU, RĂZVAN DĂNULESCU and FLORIN MIHAI
TUFESCU, Some Features of Electric and Magnetic Fields Emitted by CRT
Computer Monitors (English, Romanian summary). . . . . . . . . . . . . . . . . . . . .
MIHAELA MIRON and MONA-LISA CAZACU, Optical Centered System of
the Human Eye (English, Romanian summary). . . . . . . . . . . . . . . . . . . . . . . . .
77
83
89
97
105
115
123
129
137
167
177

SOME EXACT SOLUTIONS FOR THE FLOW
OF A GENERALIZED OLDROYD-B FLUID BETWEEN
TWO SIDE WALLS PERPENDICULAR TO A PLATE
BY
AZIZ ULLAN AWAN, CORINA FETECĂU, MUHAMMAD IMRAN
Abstract: New exact solutions for the unsteady flow of a generalized Oldroyd-B
fluid induced by a suddenly moved plate between two side walls perpendicular to the plate
have been established under integral and series form in terms of the generalized Mittag-
Leffler functions. Similar solutions for generalized second grade fluids and Maxwell fluids
with fractional derivatives as well as those for ordinary models are obtained as limiting cases
of general solutions. In the absence of the side walls, all solutions that have been determined
reduce to the solutions corresponding to the motion over an infinite plate (first problem of
Stokes).
Key words: generalized Oldroyd-B fluid, suddenly moved plate, exact solutions.
ON THE AXIAL COUETTE FLOW OF A MAXWELL FLUID DUE
TO A LONGITUDINAL TIME DEPENDENT
SHEAR STRESS
BY
WASEEM AKHTAR, MUHAMMAD JAMIL
Abstract. A study is made for the unsteady flow of a Maxwell fluid in an infinite
circular cylinder. The motion is produced by the infinite cylinder that at the initial moment
is subject to a longitudinal time dependent shear stress. The velocity field and the associated
shear stress corresponding to the longitudinal flow are determined by means of the Hankel
and Laplace transforms. Both solutions are written in terms of the generalized G-functions.
The similar solutions for Newtonian fluids are obtained as limiting cases from our general
solutions.
Key words: Tangential stress, Maxwell fluid, velocity field, cylindrical domains

NEW EXACT SOLUTIONS CORRESPONDING TO
STOKES’ SECOND PROBLEM FOR MAXWELL FLUIDS
BY
IMRAN SIDDIQUE, QAMMAR RUBBAB
Abstract. In this paper new exact solutions for Stokes’ second problem for Maxwell
fluids are presented by considering both sine and cosine oscillations of the plate. These new
starting solutions, obtained by means of Laplace and Fourier sine transforms, describe the
flow for low and high values of time t, and are presented as sums of steady-state solutions
and transient solutions. In our paper we determine not only the velocity field, but also the
resulting shear stress. The time values required to reach the steady flows are also determined
by means of numerical methods. The solutions corresponding to Stokes’ second problem for
Newtonian fluids, as well as the solutions corresponding to Stokes’ first problem for
Maxwell and Newtonian fluids are obtained as particular cases from our solutions.
Key words: Maxwell fluids, exact solutions, velocity field, shear stress.
SELF-DUAL GAUGE FIELDS ON
NON-COMMUTATIVE SPACE-TIME
BY
GHEORGHE ZET
Abstract. A self-dual gauge theory is developed considering U(2) as local symmetry
group. Using the gauge fields, the covariant derivative is constructed and the strength tensor
components are calculated. The self-duality equations are written and a solution for the gauge
fields is obtained in the case of commutative space-time. The results are extended to the noncommutative
space-time defined by the condition ⎡
µ ν µν
x , x ⎤
µν νµ
⎣ ⎦
= i θ , with θ = − θ as
constant (canonical) parameters of the model. The gauge fields are expanded as power series
of θ - parameters and their components are calculated order by order using the self-duality
equations. An example of non-commutative self-dual solution is given and some of its
properties are discussed.
Key word: self-dual gauge fields, non-commutative space-time

SELF-DUAL SU(2) GAUGE THEORY OVER A
4-D SPACE-TIME WITH SPHERICAL METRIC
BY
CAMELIA POPA, DOINA PARTENIE
Abstract. A model of the SU (2)
gauge theory is constructed over a four
dimensional space-time endowed with spherical symmetric metric. We choose a particular
form for the gauge potentials A µ , depending only upon two unknown functions of the r
coordinate, W(r) and U(r). We calculate these potentials supposing that the chosen metric
assures the property of self-duality for the field strength tensor . F µν
Key words: gauge theory, self-dual model, SU(2) group, Schwarzschild metric,
MociuŃchi metric.
FERMIONS ON 5D WARP OF EINSTEIN UNIVERSE
BY
MARINA-AURA DARIESCU, CIPRIAN DARIESCU,
ANA-CAMELIA PÎRGHIE
Abstract. The present paper deals with fermions minimally coupled to a 5D space,
3
with four-dimensional slices being the S × R spacetime. By solving the Einstein equations
with a perfect fluid source, we find the expression of the warp factor and write down the
corresponding Dirac-type equation. We are obtaining the wave equation of chiral right and
left fermions along the extra dimension and derive the complete set of closed form solutions
3
to the Dirac-type equation on S × R topology, by employing the group theoretical methods.
Key words: Einstein Universe, branes, 5D Dirac-type equation.
OBSERVATION OF A TORUS DOUBLING EVOLUTION TO
CHAOS IN AN RLC CIRCUIT WITH MFS CAPACITOR
AS NONLINEAR ELEMENT
BY
CRISTINA STAN, CONSTANTIN P. CRISTESCU, BOGDAN MEREU
Abstract. In this work we focus on the change in dynamics induced by the
sinusoidal driving with constant amplitude and variable frequency in an RLC electric circuit
with a metal – ferroelectric semiconductor heterostructure (MFS) as nonlinear capacity. The
investigated dynamical changes consist in a torus doubling bifurcation scenario of evolution
to chaos. The necessary condition of observation of torus doubling bifurcation (a four
dimensional system) was achieved by addition of a small capacitance in parallel with the
inductor in a series RLC previously studied circuit.
Key word: sinusoidal driving, electric circuit, rout to chaos.

SIMULATING AND MODELING TURBULENCE AND CHAOS
IN FUSION PLASMAS USING LOGISTIC MAP
BY
VIOREL STANCU, LIVIU BĂDELIłĂ
Abstract. The aim of this paper is to underline the importance of the logistic map
in modeling of turbulence and chaos in fusion plasmas and to present numerical results
concerning the simulation of the transition to turbulence and chaos in plasmas using the
logistic map.
Key words: turbulence, chaos, fusion, plasmas, computer simulation, logistic map.
ON THE EFFECTS OF LOW PRESSURE ARGON PLASMA
TREATMENT ON PVA FILMS
BY
OANA NICULESCU, CRISTINA-DELIA NECHIFOR
Abstract. This study shows the way in which diffusion Argon plasma acts on poly
(vinyl alcohol) films. The set-up consists in a glass chamber in which plasma was obtained
by ionization of Ar atoms as a result of collision with electrons accelerated under a bias
voltage. The films were analyzed using ATR-FTIR, by means of Bruker Vertex 70 type
spectrometer (U.S.), with a diamond crystal having a 6 mm 2 surface. Morphology of these
films was studied with AFM technique at a resolution of 5 µm. Both the morphology and the
physico-chemical properties of the film surface change with treatment time.
Key words: plasma, poly (vinyl alcohol), roughness.
ELECTROMAGNETIC PROPERTIES OF CHIRAL
METAMATERIALS
BY
VALERIU DAVID, MARIANA LATU
Abstract. The paper reports a theoretical study of electromagnetic waves in a chiral
metamaterial. We have obtained the differential equations of the electric and magnetic
component of wave, taking into account the conductivity of the medium and the volume
charge density. Using this equation it is possible to determine the nature of waves (forward,
backward or forward and backward) in the chiral slab.
Key words: electromagnetic waves, chiral, metamaterial, differential equation,
forward wave, backward wave.

PROPAGATION VELOCITY AND ATTENUATION COEFFICIENT
OF AN ULTRASOUND WAVE
IN A FERROFLUID
BY
RODICA BĂDESCU, VASILE BĂDESCU, GABRIELA APREOTESEI
Abstract. We present the results of our study on the propagation velocity and on
the attenuation coefficient of an ultrasound wave (US) in a ferrofluid based on kerosene. We
studied the dependence of these parameters on the concentration of magnetite particles, on
the density of ferrofluid, and on the applied magnetic field intensity. We compare the results
with those corresponding to normal fluids.
Key words: ferrofluid, ultrasound, propagation velocity, attenuation.
DISCREET NANOSTRUCTURES OF Pb, Sn, Cu, Ni
BY ARC-DISCHARGE SYNTHETIZED
BY
GABRIELA CĂLIN, FELICIA CARMEN DASCĂLU, ADINA COROABĂ,
FLORIN BRÎNZĂ, NICOLAE SULIłANU
Abstract. Since of the discovery of nanostructures, enormous research has been
devoted to their synthesis and characterization due to their unique properties and large area
of applications (microelectronics, optics, sensors etc). Many techniques have been
developed to produce discreet nanostructures (nanowires, nanoparticles, SWNTs, MWNTs
etc.) such as laser ablation, arc-discharge, chemical vapor deposition and others. Due of this
reasons, fabrication of nanostructures using different materials and methods is a rapidly
growing field of interdisciplinary research. One of the main challenges is to find a way to
produce them on a large scale and at low cost [1].
In this paper we will describe most used methods in obtaining discreet
nanostructures, especially one who is in progress in our laboratory and also the results on
synthesis of nanostructures produced by submerging graphite electrodes in liquid
environments and passing a current between the electrodes to form a plasma arc [3].
Key words: discreet nanostructure, graphite, fullerene, amorphous, electric arc,
carbon nanotubes.

GALVANOMAGNETIC EFFECTS OF NEW CoFeSiBMo ALLOY
BY
MIHAI LOZOVAN, HORIA CHIRIAC, VIOREL DOBREA,
MIHAIL-LIVIU CRAUS, SERGIU MOHORIANU
Abstract. Results concerning measurements of the Hall resistivity, spontaneous Hall
coefficient, longitudinal and transversal magnetoresistance and ferromagnetic anisotropic
resistivity for as-cast and thermally treated Co 65.75 Fe 4.5 Si 12.25 B 15 Mo 2.5 amorphous ribbons
are presented. The obtained results show a strong dependence of the electrical properties of
the samples on the thermal treatment. In the nanocrystallized samples the value of
ferromagnetic anisotropic resistivity (+1.65·10 –4 ) is quite similar to that of the amorphous
samples (+1.17·10 –4 ). In the crystallized state the value of ferromagnetic anisotropic
resistivity increases up to +17.93·10 –4 .
Key words: magnetoresistance, Hall effect, ferromagnetic anisotropic resist- ivity
CORE SHELL PHOSPHORESCENT COMPOSITES APPLIED
IN OPTOELECTRONICS
BY
CORNELIU STAN, MARIUS SEBASTIAN SECULA,
DANA TUTULEA, DOINA SIBIESCU, IOAN ROŞCA, IGOR CREłESCU
Abstract. In the present paper, beside a brief literature review concerning the
fabrication of some illumination systems based on phosphorescent composites, some
polymeric matrices based on PET and co-polymeric PET/PEG, very promising for the
lighting-source applications, are also presented. The specific advantages of these polymers
(high thermal and UV stability, high transparency, high melting and transition temperatures
and lack of toxicity) represent the fundaments for obtaining new composites with
phosphorescent properties adapted to the requirements of their applications. Also, some
experimental tests were performed in order to achieve some PET and co-polymeric
PET/PEG matrices aiming at enhancing phosphorescent nanocomposite performances.
Key words: phosphorescent nanocomposite, quantum dot, polymeric matrix,
PET/PEG block copolymer.

THERMODYNAMIC PROPERTIES OF (TOLUENE + AN ALKANE)
AT 298.15 K
BY
GEORGIANA BOLAT, ADRIAN CĂILEAN, DANIEL SUTIMAN,
DANIEL MARECI
Abstract. This article presents the experimental data of mixing properties for a set
of five binary mixtures formed by an aromatic hydrocarbon, toluene with octane, or decane,
or dodecane, or tetradecane, or hexadecane mixtures. The excess enthalpies H and excess
volumes
V were measured at T = 298.15 K for all systems. All experimental values are
E
m
correlated with a new suitable parametric equation, which is function of the so-called active
fraction.
Key words: excess enthalpy, excess volumes, binary mixtures, toluene,
density.
E
m
VISIBLE BIREFRINGENCE OF PVA THIN FOILS
BY
CRISTINA-DELIA NECHIFOR, ECATERINA ANGHELUłĂ,
DANA-ORTANSA DOROHOI
Abstract. Thin foils of poly (vinyl alcohol) were prepared and dried without
modifying their separation surfaces. The obtained films and the stretched ones were
analyzed with a polarizing microscope from their anisotropy point of view.
The birefringence of anisotropic films was determined using a Babinet
Compensator. An increase of birefringence versus the stretching degree of foils was
evidenced for all studied samples.
Key words: birefringence, Babinet compensator, stretching degree.
EFFECTS OF ELECTRON BEAM IRRADIATION ON
AQUEOUS SOLUTION OF CORN STARCH
BY
MONICA R. NEMłANU, MIRELA BRAŞOVEANU
Abstract. The paper deals with the investigation concerning the influence of the
electron beam treatment (doses up to 10 kGy) on the 5% aqueous solution of corn starch.
pH, clarity and its stability, color, and flow behavior were analyzed for the studied samples.
The value of pH and clarity decreased as the increase of the irradiation dose. The color of
the irradiated solutions showed a shift toward red-yellowish one with the increase of the
chromaticity at same time with the reduction of the hue and lightness in a dose-dependent
manner. The flow behavior was influenced by reduction of the viscosity value with the
irradiation dose.
Key words: starch, irradiation, solution, physicochemical properties

THE GEOELECTRICAL - RHEOELECTRICAL METHOD
FOR THE MANAGEMENT OF UNDERGROUND WATER
BY
DANIEL TOACĂ, IOSIF BARTHA, RODICA MARIA NEAGU,
NICOLAE MARCOIE
Abstract. This paper proposes a combination of two electrical methods: the
geoelectrical tomography and the rheoelectrical investigation of underground water
sources. Both methods are using the analogy in some situations with the basic equations of
electrodynamics and hydrodynamics.
This is a new method that we propose for a nondestructive investigation of caption
front for an utilization of underground water in several proposes.
Key words: geoelectrical tomography, rheoelectrical investigation, water sources.
AN ANALYSIS OF A HIGH GRADIENT MAGNETIC SEPARATOR
FOR EXTRACORPOREAL BLOOD PURIFICATION
BY
VASILE BĂDESCU, LAURA-ELENA UDREA, OVIDIU ROTARIU, RODICA
BĂDESCU, GABRIELA APREOTESEI
Abstract. We analyze and prove the feasibility of a model of HGMS magnetic
separator for extracorporeal blood purification of excess chemo- or radio-therapeutic drugs
from cancer patients or for eliminating toxin-bounded magnetic spheres from the
bloodstream. The separator consists of an array of capillary tubing and magnetizable wires
adjacent in the exterior of these. The wires are magnetized perpendicular to their axes by a
magnetic field generated by two parallel magnets. The capture efficiency of a single
separation cell is investigated using a mathematical model.
Key words: magnetic separator, blood detoxification, magnetic microsphe-res.

SOME FEATURES OF ELECTRIC AND MAGNETIC SEPARATION
OF NANOSPHERES FROM A SIMULATED BIOLOGICAL FLUID
BY
LAURA-ELENA UDREA, VASILE BĂDESCU, OVIDIU ROTARIU , RODICA
BĂDESCU, GABRIELA APREOTESEI
Abstract. We are working in developing a tool for rapid removal of biohazards
from human blood. For this we realized a mini magnetic separator capable of separating
magnetic nano/micro-carriers from arterial blood flow in an ex vivo unit. Here we evaluate
the performance of our separator. Pure water and ethylene glycol–water solutions with a
viscosity of 3.0 cP and 4.0 cP (v:v = 39:61 and v:v = 49:51, respectively) were used as the
fluids. The results demonstrated the feasibility of achieving high capture efficiency for blood
in the prototype magnetic separator for biomedical applications.
Key words: magnetic separator, blood detoxification, extracorporeal unit, in vitro
tests.
SOME FEATURES OF ELECTRIC AND MAGNETIC FIELDS
EMITTED BY CRT COMPUTER MONITORS
BY
CRISTIAN GOICEANU, RĂZVAN DĂNULESCU,
FLORIN MIHAI TUFESCU
Abstract. The aim of our study is to determine electric and magnetic field levels as
well as spectral composition of emissions in the proximity of some CRT computer monitors.
Field measurement and analyze were carried at distances up to 0.7 m from computer
monitors. Broad-band level measurements, as well as spectral analysis covered the low
frequency domain up to 32 kHz. Measured levels of electric and magnetic field are low
comparing to the limits set by human exposure standards. Spectral analysis showed
interesting differences in present components and weight of various frequencies between
different models of monitor.
Key words: CRT monitors, electric and magnetic fields, spectral analysis.
OPTICAL CENTRED SYSTEM OF THE HUMAN EYE
BY
MIHAELA MIRON, MONA-LISA CAZACU
Abstract. In the hypothesis that human eye is an optical centred system, the
cardinal elements of the human eye were calculated and used in order to obtain the image of
an object in Gaussian approximation.
Key words: eye cardinal elements.