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Periodicals - LEBANESE SCIENCE JOURNAL VOL.2, NO.2, 2001
Natural and Environmental Sciences
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Seasonal and Altitudinal Effects on Thermoregulation and Semen
Quality Variables of Awassi Rams
S. Abi Saab, B. Jammal, R. El-Khoury
Experiments were carried out during moderate and hot seasons on
10 Awassi adult rams situated at different locations: the central
coast (~150 m) and mountain region (~1150 m) to determine seasonal
and altitudinal effects on thermoregulation and semen quality. All
rams received the same diet (14.2 % crude protein) and were confined
under similar conditions. Climatological data, indicators of adaptation
(respiration and pulse rates, rectal temperature), body weight,
scrotal dilatation and scrotal circumference as well as semen characteristics
(volume, sperm concentration, motility and abnormality) were registered
on weekly basis. Results showed that, during the moderate season
at both altitudes, the respiration rate was significantly lower
(55.7 and 34.7 vs 71.4 and 49.0 breath/ min, respectively) with
the lowest recorded value (34.4 ± 15.2) at the 1150 m altitude,
while the pulse rate was significantly higher (100.6 and 95.1 vs
82.2 and 86.5, beats/ min, respectively) as compared to the hot
season. Body temperature in both seasons was also significantly
lower (39.3 and 39.0 ºC, respectively) at the 150 m altitude
in comparison with the results obtained at 1150m (39.5 and 39.1,
respectively). However, body temperature did not differ significantly
among seasons at the 1150 m altitude. The recorded values for scrotal
dilatation were slightly higher at the 150 m altitude for both seasons
with largest dilatation scores (16.2 cm) occurring at the hot season.
Semen volume and motility increased significantly during the hot
season at both altitudes, whereas sperm concentration was significantly
higher during both seasons at the high altitude with no significant
changes in semen abnormality. It is concluded that hot season at
high altitudes did not adversely affect the animal physiological
parameters as well as its semen volume and quality.Back
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Antimicrobial Effects of the Extracts of Hypericum thymifolium
Christo Hilan and Rabiha Sfeir
Hypercium thymifolium (Ht) a medicinal herb used throughout history,
has always been of great interest to people. It is known in Lebanon
as “Dazi” and grows wild in vast areas of the country.
Fresh green leaf samples of Ht were collected from three Lebanese
regions, and extraction of essential oil was done using hydro-distillation,
followed by Gas Chromatography analysis. The buds of flowering tops
of Ht were tested for the level of hypericin with HPLC. The inhibitory
effect of the extract on bacteria and yeast were tested using a standard
microbiological assay. The odor of its flower is fresh turpentine-like,
then fruity, attracting honeybees, especially, in the early morning.
The high lipid solubility of the Ht essential oil extract gives a
milky liquid with a thin oily layer on the surface. Hydro-distillation
yielded 0.5% oil, which is rich in essential oils (limonene16.7%,
geranyl acetate 15.54%, terpineol 7.6%, and geraniol 2.5%). Hypericin,
which is a bright red pigment dianthrone derivative, is a natural
product found in the Ht yellow flower. The total yield of hypericin
was around 0.25% (Dry weight). The Ht milky oily extract had outstanding
antibacterial properties and was much more potent than the commonly
used antibiotics tested. Results of the study indicate that this compound
showed strong inhibitory activity against Staphylococcus aureus and
was more effective than Sulphamethoxazole. The Ht extract killed 12000
Staphylococcus bacteria, as compared to 137 only by the antibiotic.
Its remarkable activity against some gram (+) positive and gram (-)
negative bacteria offers enormous potentials for medicinal use.Back
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The Threonine Requirement of Starter Male Turkey Poults
M.L. Lilburn and G.W. Barbour
Two experiments were conducted to determine the threonine requirement
for maximum performance, breast and drum major muscle growth in male
turkey poults raised from 0 to 2 and 3 to 5 weeks of age. A corn-peanut
meal basal diet with 23.1% crude protein, 2962 Kcal metabolizable
energy (ME)/Kg and 0.65% threonine was fed to poults in both experiments.
Four increments of 0.15% L-threonine each were added to the basal
diet. In the first experiment each treatment was randomly replicated
among four cages with five poults in each cage. In the second experiment
male poults were randomly distributed among grower cages with three
poults in each cage and seven cages per experimental treatment. Maximum
performance and gastrocnemius muscle weight of male turkey poults
were supported by feeding a corn-peanut meal diet containing 0.80%
threonine or 2.70 g threonine/Mcal ME from 0 to 2 and 3 to 5 weeks
of age. The threonine requirement that supported maximum growth of
the pectoralis major muscle could be estimated, however, it was considered
to be lower than 0.65% of diet as well as the threonine requirement
for maximum gastrocnemius muscle growth. Back
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Fundamental Sciences, Engineering and Technology
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Elements for Multi-Criteria Modeling of Urban Storm
Drainage Network Planning
A. Karnib, O. Blanpain,
J. Al-Hajjar , D. Boissier
This paper deals with the problem of comparison of urban storm drainage
network upgrading alternatives from the economic, operational and
environmental point of view. First the conditions required for an
accurate comparison are outlined. Then the evaluation of a criterion
governing the operation of a storm drainage network is presented.
It allows the evaluation of the sensitivity of urban areas to the
operation failure of the storm drainage network. This criterion is
developed by using an expert system approach based on fuzzy inference.
The produced results allow the designer to classify the different
network upgrading alternatives according to their impacts on urban
areas and to introduce this order in a multi-criteria decision making
method. The application of the fuzzy sets theory to characterize the
evaluation of alternatives leads to a specific formulation of fuzzy
decision problem. A suitable multi-criteria decision making method
is then presented. Lastly, a practical application to urban storm
drainage network upgrading is given and its applicability is discussed.Back
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Minimum Lateral Reinforcement
in Reinforced Concrete Columns
Yehia A. Daou and Eyad Seifeddin
The ACI Building Code (ACI 318-99) requires minimum lateral ties or
links of at least 3/8 (#3) inch in diameter and spaced not over 16
bar diameters, 48 ties diameter, or the least dimension of the column.
When more than four bars are used, additional ties are to be provided
so that longitudinal bar is held firmly in its position and has lateral
support equivalent to that provided by a 90 degree corner of a link
exempting bars which are located within 6 inches clear on each side
along the tie from adequately tied bars. The British Standard BS 8110
also gives requirements for the provision of minimum links in columns.
The ties are limited to at least ¼ the size of the largest
longitudinal compression bar with a maximum spacing of 12 times the
size of the smallest compression bars. Review of other codes of practice
also reveal similar limitations in design for ties in reinforced concrete
columns.
The aim of the work presented in this paper is to study the significance
of minimum link requirements and to determine the effect, if any,
on the ultimate capacity of the column and providing a lower amount
of lateral reinforcement.Back
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Etude de l’Alimentation par Onduleurs de Tension d’une
Machine Synchrone Multi-Etoile
N. Moubayed, F.
Meibody-Tabar, B. Davat
Dans cet article, les auteurs s'intéressent à la segmentation
de l'alimentation par onduleur de tension des machines synchrones
de forte puissance. Une modélisation d'une machine synchrone
à n étoiles alimentée par n onduleurs indépendants
permet de mettre en évidence les problèmes liés
au couplage et au décalage des enroulements, en particulier
vis à vis de l'apparition d'oscillations du courant d'alimentation.
La mise en équation du système est suivie par différents
résultats de simulation.Back
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Stability of the Zero Solution of Volterra Systems of the Second
Kind Difference Equations
Youssef N. Raffoul
Lyapunov functionals are used to obtain some stability results about
the zero solution of linear Volterra systems of difference equations.
Back
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A New Approach in the Rayleigh - Schrödinger Perturbation
Theory for the Rovibrational Problem
M. Korek
For a transition vJ<--> v'J' (J'=Ją1) the eigenvalues and
the eigenfunctions of the two considered states can be expressed
respectively in terms of one variable m (transition number), relating
these two states, as
Evm=Σi=0 e(i)v
mi, Ψvm = i=0φ(i)vm
and Ev'm=Σi=0 e(i)v'
mi, Ψv'm=Σi=0 φ(i)v'
mi , where m=[J'(J'+1)-J(J+1)]/2, and the coefficients
e(i)v, φ(i)v, e(i)v',
φ(i)v'are given by analytical expressions.
This new expansion in the perturbation theory permits a direct calculation
of many factors in spectroscopy that are expanded in terms of m
as the line intensities, the wave number of a transition, the Herman-Wallis
coefficients, ... etc. The numerical application shows that the
present unconventional approach in the perturbation theory provides
a simple and accurate method for the calculation of the eigenvalues
and the eigenfunctions for the two considered states of the molecule
CO and for the calculation of the Herman-Wallis coefficients for
the ground state of the molecule HCl.Back
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Modélisation des Turbines Radiales de Suralimentation
M. Mseddi, M. Baccar, H. Kchaou et M. S. Abid
Pour contribuer à l'étude globale des turbines radiales
de suralimentation, un modèle de calcul se traduisant par
des équations donnant le taux de détente et le rendement
isentropique, est présenté. Ces équations permettent
de prédire à partir des données géométriques
d’une turbine radiale, ses caractéristiques de fonctionnement
à froid en régime stationnaire. Le modèle permet
également de trouver les points de fonctionnement inaccessibles
par l’expérience. Le calcul du taux de détente
repose sur la combinaison de deux états de la turbine, un
état statique dans lequel la roue est bloquée et un
état dynamique dans lequel la roue tourne à une vitesse
angulaire constante.Le calcul du rendement suppose qu’il y
a réduction du moment cinétique entre l'entrée
volute et l'entrée roue et qu'il y a glissement des filets
fluides à la sortie roue.Le modèle proposé,
a été testé sur une turbine radiale de suralimentation
de type GARRETT TA03 pour moteur d’automobile, et présente
d'excellents résultats.Back
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