African
Journals Online
Global Journal of Pure and Applied Sciences
Volume. 9 Number 2 March 2003
Abstracts
Changes
in activities of polyphenol oxidase, ascorbate, peroxidase,
hydroperoxide and lipid levels during desiccation of Irvingia
gabonensis (variety excelsa) seeds.
P.
J. Nya, D. N. Omokaro and A. E. Nkang
Department
of Botany, University of Calabar, Calabar, CRS Nigeria
ABSTRACT
Activities
of peroxidase (POD), Polyphenol oxidase (PPO), hydroperoxide and lipid
contents were investigated during desiccation of cotyledonary tissues
of Irvingia gabonensis at ambient temperature (26OC
- 30OC), 35OC and 20OC. Activities of
POD and PPO increased initially but declined in the latter desiccation
period. However, loss of enzymic activity (POD and PPO) occurred
generally at moisture content less than 20%. The hydroperoxide and
lipid levels increased during desiccation irrespective of stage of
seed development. Results suggest that seeds show peroxidation with
drying, that is spontaneous oxidation of unsaturated fatty acids.
Lipid peroxidation was very pronounced in Irvingia gabonensis
seeds indicating the need for rapid drying at relatively high
temperature in order to maintain seed quality.
Key
Words:
POD: Peroxidase; PPO: Polyphenol oxidase; RMC; Relative Moisture
Content; Irvingia gabonensis
A
preliminary survey of micro-organisms in the gut and pellets of a
tropical millipede Doratogonus uncinatus attems (Diplopoda,
Spirostreptida, Spirostreptidae)
Mwabvu,
T Biological Sciences Department, Midlands State University, Bag 9055,
Gweru, Zimbabwe.
Mswaka,
A., Mlambo, G.,Biological Sciences Department, University of Zimbabwe,
Box MP 167, Mount Pleasant, Harare,Zimbabwe. Email:
[email protected]
ABSTRACT
Millipede
gut microbiology and decomposition of faecal pellets over a period of
eight weeks were studied in the laboratory. Bacterial numbers, carbon
and nitrogen content, pH and weight loss were monitored. Heterotrophic
bacteria were the most abundant and reached a peak in the first two
weeks of decomposition. The amount of carbon was constant while
ammonium nitrogen decreased from 1.51 % to 0.03 % after eight weeks.
The pH of the pellets was slightly acidic and did not change much
during the course of decomposition. A succession of micro-organisms
was observed on decomposing pellets. Zygomycetes were replaced by
Ascomycetes after 20 days of decomposition. Decomposition was
significantly affected by temperature. The rate of decomposition was
highest at 35oC.
Key
words:
decomposition, pellets, bacteria, fungi, succession
Effects
of roasting and soaking on the proximate composition and functional
properties of selected tropical legumes
Stanislaus
U. Okorie* and Elizabeth C. Amaechi
Department
of Food Science and Technology, Imo State University, Owerri, Nigeria
ABSTRACT
Proximate
composition and functional properties of roasted and soaked Afzelia
africana “akpalata”, Brachystegia eurycoma “achi”
and Detarium microcarpum “ofo” were studied. Result
indicated no significant differences (P>0.05) in ether extract of
the processed legumes but roasted B. eurycoma, A africana
and D. microcarpum had the highest values. Also, no significant
differences (P>0.05) were observed in the crude fibre and moisture
contents of the three legumes. Control (raw) and soaked B. eurycoma
and A. africana compared very well in ash contents but no
significant differences (P>0.05) were observed in the raw, roasted
and soaked D. microcarpum legumes. Roasting and soaking
improved the crude protein contents of B. eurycoma and D.
microcarpum while there was a decrease in the protein contents of A.
africana. Although, the swelling index of the processed B.
eurycoma and D. microcarpum respectively compared
favourably with their raw legumes, the soaked (2.16 ml/g) A.
africana was significantly better than the raw (1.7 ml/g) and the
roasted (1.50 ml/g) legumes in swelling index. Roasted and raw A.
africana showed no significant difference in oil absorption
capacity while the roasted (8.00 ml/H20/g flour) D.
microcarpum was better than the soaked (7.00 ml/H20/g
flour) and raw (6.10 ml/H20/g flour) in water absorption
capacity. Least gelation concentrations for raw, roasted and soaked
legumes were indicated as 12%, 8% and 12% (B. eurycoma). 18%,
16% and 14% (A. africana) and 6%, 4% and 6% (D. microcarpum)
respectively. Roasting and soaking decreased the emulsion capacities
of B. eurycoma, A. africana and D. microcarpum.
The three processed legumes were significantly higher than their raw
legumes in thermal gelation temperature.
Keywords:
Roasting, soaking, proximate composition, functional properties,
tropical legumes.
Response
of microbial enzymes syntheses to toxicity of weathered and
biodegraded oils.
I.
O. Odokuma and G. C. Okpokwasili
Department
of Microbiology, University of Port-Harcourt, Port-Harcourt, Nigeria
ABSTRACT
The
toxicity of eight weathered and biodegraded Nigerian crude oils to the
biosyntheses of four bacterial enzymes were examined. The constitutive
intracellular enzyme, nitritase was the most sensitive to all
toxicants. Two extracellular inducibe enzymes tryptophanase and α-glucosidase
were less, sensitive to the toxicants. These extracellular enzymes,
however, were more sensitive than the intracellular inducible enzyme
β-galactosidase. Inhibition of bacterial enzymes syntheses could
be a useful, cheap, simple rapid ecotoxicity assay for monitoring oil
pollution in the Nigerian environment.
Keywords:
Sensitivity, Response, Microbial Enzymes, Toxicity, Weathered crude
oil, biodegraded crude oil.
Effects
of tannins and polyphenols of some medicinal plants on bacterial
agents of urinary tract infections
U.J.J
Ijah and F.O. Oyebanji
Department
of biological sciences, Federal University of technology P. M. B 65,
Minna, Nigeria.
ABSTRACT
Five
medicinal plants, Enantia chloranthia, Kigelia africana,
Bridelia ferruginea, Trema nitems and Drypetes
gossweilerri were screened for phytochemical components. The
plants were found to contain tannins, phlobatannins, alkaloids,
cardiac glycosides, anthranoids, anthraquinones, saponins and
polyphenols. The crude aqueous and ethanolic extracts as well as
tannins and polyphenols of the plants were tested on some bacterial
agents of urinary tract infections (UTI). The results revealed that
the extracts inhibited Staphylococcus aureus, Pseudomonas
aerugosina, Klebsiella sp., Proteus sp. and Escherichia
coli to varying degrees. However, the ethanolic extracts showed
greater degree of inhibitory activity on the organisms than the
aqueous extracts. Similarly, the tannins and polyphenols inhibited S.
aureus, Klebsiella sp., Proteus sp. and E. coli
but had no inhibitory effect on Pseudomonas aeruginosa. The
minimal inhibitory concentration (MIC) values for the test bacteria
varied but generally ranged between 3% and 7%. Mixing the ethanolic
extracts of all five medicinal plants together resulted in lower MIC
values for the organisms. The utilization of these plants for the
manufacture of drugs for the treatment of UTI is highlighted.
Keywords:
Tannins,
polyphenols, bacteria, urinary tract infections
Influence
of electrical conductivity on microorganisms and rate of crude oil
mineralization in Niger Delta Ultisol
J.
P. Essien, A. Y. Itah and S. I. Eduok
Department
of Botany and Microbiology, University of Uyo, Uyo, Nigeria
ABSTRACT
The
effect of salinity on the population density of hydrocarbonoclastic
microorganisms and oil degradation in a tropical ultisol was
determined. Soils were simulated with 50gkg –1 of Qua
Iboe Light (QIL) crude oil. Salt treatments included NaCI amendments
to adjust the soil solution electrical conductivities (EC) to 40. 120
and 200 dSm-1. Treated soils were incubated at 28oC.
Oil degradation was estimated from the gravimetric determinations of
remaining oil. The result showed that amending the ultisol with crude
oil stimulated the growth of oil degrading microorganisms, while salt
concentration inducing an EC of 200 dSm-1 in oil amended
ultisol resulting in a decrease in the amount oil mineralizd. A
significant positive correlation was found between the number of
hydrocarbonoclastic microorganisms and levels of oil mineralization at
EC 40 dSm-1 (r= 0.980, p =0.05) and EC 120 dSm-1
(r=0.976, p= 0.05) except at EC 200 dSm-1 (r =0.855, p =
0.05). This is an indication that desalting of soils contaminated with
oil and salts is required for a speedy bioremediation of an ultisol
Keywords:
Electrical conductivity, crude oil, hydrocarbonoclastic
microorganismineralization.
Effect
of levels of bacillus spp as inoculum on ph and titratable acidity
during controlled fermentation of soybean to dawadawa.
C.A.
Emmanue-Ikpeme, A.O. Oguntude, C.O. Aworh
Department
of Biochemistry, University of Calabar, Calabar, Nigeria
ABSTRACT
Effect
of levels of Bacillus subtilis and Bacillus licheniformis
used singly or in combination as inoculum on pH and titratable acidity
(TA) development during soybean fermentation for dawadawa production
were investigated. Soybean seeds were processed and then fermented
with 0.01%, 0.025%, 0.05%, 0.075% and 10% levels of B.subtilis
and B. lichenformis inoculum in singles or in combination. The
results showed that there was a significant increase (p<0.05) in
titratable acidity values at all the levels of B. subtilis and B.
lichenformis used singly or in combination as inoculum.
Fermentation time and inoculum levels as titratable acidity changes
resulted in significant increase in titratable acidity. Fermentation
of soybean with B. licheniformis showed that inoculum levels
(0.01%, 0.025%, 0.05%, 0.075%, 0.10%) used as titratable acidity
changes were not significant (p<0.05). pH values increased
significant (p<0.05) at all levels of Bacillus spp used singly or
in combination. Fermentation time and inoculum levels (0.01%, 0.025%,
0.05%, 0.075%, 0.10%) used for B. subtilis were significant
(p<0.05). There was no significant difference in the product
quality attributes based on inoculum type and levels used as evaluated
by sensory panelists. Therefore, dawadawa could be produced using
either B. subtilis or B. licheniformis.
The
influence of macronutrient deficiencies on chemical composition of
dwarf green coconut (Cocu nucifera linn)
seedling
B.O.
Ejedegba and E. C. Onyeneke
Chemistry
Division, Nigerian Institute for oil palm research (NIFOR) Benein City
ABSTRACT.
The
influence of macro nutrient deficiencies on chemical composition of
Dwarf green coconut seedling was studied in the Nursery site of NIFOR
substation Abak for a period of 15 (fifteen) months. Reduction in
magnesium improves protein content while reduction of nitrogen,
magnesium and potassium reduces height and girth of shoots.
Elimination of magnesium also leads to reduction in the concentration
of chlorophyll. starch and sugar concentrations improved with nitrogen
and potassium but decreased with were more pronounced in roots than
shoots in all cases.
Key
words:
Macronutrient effect on dwarf green coconut.
Evaluation
and characterization of the seed oils of Trichosanthes cucumerina
(snake gourd) and Ricinodendron heudelotii (honey plum)
V.
S. Ekam
Department
of Biochemistry, University of Calabar, Nigeria
ABSTRACT
The
estimation of the chemical composition and physical properties of the
seed oils of Trichosanthes cucumerina and Ricinodendron
heudelotii using standard methods of analysis showed that the seed
of T. cucumerina and R. heudelotii have high oil content
(46.3±4%
and 42.5±5%
respectively). Assessment of the physical constants revealed that Ricinodendron
heudelotii had a low heat of combustion (12.9 ±
3kcal/g) when compared to that of Trichosanthes cucumerina
(32.8 ±
4kcal/g). The refractive indices at 400C, boiling point,
smoke point and flash points were high in the two oils. Their relative
densities were high and their melting points were low. From the
chemical parameters, the high ester value and saponification values of
T. cucumerina and R. heudelotii qualifies them to be
used in industries for soap making, while the high iodine value for R.
heudelotii (158.8 ±
8gI/100g oil) qualifies it as a drying oil and suggest possible
usefulness in the paint industry. Their percentage free fatty acid and
acid values were low suggesting increased stability and usefulness in
nutritional and industrial applications.
Key
Words:
seed oil, chemical composition, Trichosanthes cucumerina, Ricinodendron
heudelotii.
Electrosynthesis
and characterization of conducting polypyrrole doped with
alkylsulfonate anion
K.
Anuar, A. A. Halim, A. R. Mohd. Zaki, Z. Zulkarnain, K. Dzulkefli,
A.
B. B. Nita Salina and H. N. M. E. Mahmud
Department
of Chemistry, Faculty of Science and Environmental Studies,
Universiti
Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
E-mail:
[email protected]
ABSTRACT
The
preparation of polypyrrole conducting polymer in aqueous medium by
electrochemical method containing several alkylsulfonate dopants such
as methylsulfonate (C1), butylsulfonate (C4),
octylsulfonate (C8) and dodecylsulfonate (C12)
are reported. The prepared polymer films were characterized by cyclic
voltammetry, infrared spectroscopy, scanning electron microscopy (SEM)
and elemental analysis. The conductivity of the prepared films was
found to increase with the increase of carbon number of alkylsulfonate
dopant. The results of Infrared and elemental analysis show that the
alkylsulfonate dopants were incorporated in the polypyrrole structure.
It has been observed from cyclic voltammetry analysis that lighter
dopants produced more current suggesting that the movement of the
dopants in and out of the polymer surface is much more flexible than
that of the cases for heavier dopants.
Keywords.
Conducting polymer, polypyrrole, alkylsulfonate dopant,
electrochemical polymerization, cyclic voltammetry.
In
vitro effects of anti malarial drug pyrimethamine - sulphadoxine and
activated charcoal on rat ileal smooth muscle.
A.
Nwafor
Department
of Human Physiology, Faculty of Basic Medical Sciences, College of
Health Sciences, University of Port Harcourt, PMB 5323, Port Harcourt.
ABSTRACT
The
mechanical responses of the gastrointestinal tract to anti malarial
drug primethamine-sulphadoxine (fansidar) and /or activated charcoal
(A/C) were investigated using isolated rat ileal smooth muscle.
Fansidar (5.0x10-2 to 4.5x101 M) elicited
concentration-dependent relaxation of the gut smooth muscle. ACh
inhibited fansidar induced relaxation, while atropine potentiated
action of fansidar. Although the mechanism of action of fansidar is
not clear, it is plausible that the effect of fansidar might be direct
on the smooth muscle or indirect via neurotransmitter release. The gut
vascular smooth muscle exhibited two distinct modes of signaling in
the presence of A/C and fansidar: incubation with drug followed by A/C
(5 minutes later) significantly (p <0.05) reduced the relaxation
responsiveness of the tissue as well as the concentration of the drug
compared with the situation when activated charcoal was followed by
drug. Fansidar concentration (EC50) before and after the
application of activated charcoal was 2.0x100 M and 1.5x100
M; these elicited respectively, 59% and 41% relaxation of the smooth
muscle. These studies show that fansidar relaxes gut smooth muscle,
and immediate administration of activated charcoal after drug
ingestion reduced the mechanical responsiveness of the smooth muscle
to drug. These features may render activated charcoal a unique
therapeutic agent in ameliorating the toxicological effects of
drugs/poisons in the gastrointestinal tract. There was no detectable
difference in the inherent rhythmic spontaneous activity of the ileal
smooth muscle in the presence or absence of activated charcoal (2.5x10-4
to 1.25x10-2 M).
Key
words:
Anti- malarial drug fansidar, activated charcoal- dual signaling,
relaxation
smooth muscle, ileum. Running tile: The effect of fansidar and
activated charcoal on smooth muscle preparation.
Phytochemical
screening and mineral composition of chewing sticks in South Eastern
Nigeria.
D.
E. Okwu and O. Ekeke,
Department
of Chemical Sciences Michael Okpara, University of Agriculture,
Umudike, P.M.B. 7267, Umuahia, Abia State, Nigeria.
ABSTRACT
Phytochemical
screening of the stems of Garcinia kola, Dennettia tripetala,
Acioa barteri, Dialium guineense, Maesobotrya barteri, Mallotus
oppositifolius and Psidium guajava which are commonly used
as chewing sticks in southern Nigeria revealed the presence of
bioactive compounds comprising saponins, tannins, flavonoids and
alkaloids. The major, minor and trace elements in these chewing sticks
were determined. The chewing sticks contained calcium (0.30-1.00%),
magnesium (0.06-030%), phosphorous (0.10-0.38%), potassium
(0.21-0.39%) and sodium (0.03-0.20%). The concentration of fluoride
ranged from (0.02-0.11ppm), copper (0.02-0.14ppm), iron
(2.86-5.14ppm), zinc (0.31-0.57ppm), manganese (0.00-0.26ppm) and lead
(0.00-0.11ppm). Chewing sticks when used without tooth paste is very
efficient, effective and reliable in cleaning the teeth of many people
in Southern Nigeria, The teeth of the users of chewing sticks are
usually strong, clean, fresh and devoid of dental plaques and carries.
These results indicate the basis for the preventive and protection of
the teeth against caries and plaques by the samples used.
Key
Words:
Bioactive compounds, chewing sticks, Mineral composition, Dental
plaques.
High
performance liquid chromatographic (hplc) separation of some fatty
acids as naphthyl methly derivatives using resin supported
1-naphthalene methanol as the derivatization reagent
G.O.
Adewuyi : Department of Chemical Sciences Olabisi Onabanjo University
P.M.B. 2002, Ago-Iwoye, Nigeria
O.
R. Idowu, Department of Pharmacology, Division of Experiment
Therapeutics, Wallter Reed Army Institute of Research
Washington,
D.C. 2030 –5100 and
O.A.
Adeyemi Department of Chemical Sciences, Olabisi Onabanjo University
P.M.B. 2002, Ago-Iwoye, Nigeria.
ABSTRACT
Cation
exchange resin in the sulphonyl chloride form was prepared by reacting
cation exchangers in the sodium form with calculated amount of
phosphorus pentachloride by refluxing. The sulphonyl function on the
resin serves as an anchor through which naphthalene methanol moiety
was bonded to the imobile resin backbone. The resin supported
1-naphthalene methanol was subsequently employed to derivatize some
fatty acids. The reagent imparted fluorescence property on the final
derivatives. These derivatives were obtained in pure form and simply
isolated by filtration. The derivatives absorbed UV-radiation strongly
at 254nm and direct HPLC analysis was found possible without
interference from excess reagent; This indicated that the resin
supported 1-naphthalene methanol may be employed for heterogeneous
on-line pre-or post column derivatization of fatty acids. To whom
correspondence should be addressed
Keywords:
Resin, Moiety, Derivative, Fluorescence, Heterogeneous
Determination
of trace metal levels in used lubricating oil in aqueous medium using
atomic absorption spectrometry.
Adewale
Abiodun Oladipo and Adewale Taorid Adesiyan*
Centre
for Energy Research and Development (CERD), Obafemi Awolowo University
(OAU), Ile-Ife. Nigeria.
* Author for
Correspondence, Department of Geology.
ABSTRACT
Used
lubricating oil samples from a 125 kVA diesel power generator were put
into aqueous solution by carbornization using fuming H2SO4
followed by heat - assisted digestion in a mixture of Caro’s
acid (peroxymonosulfuric acid) and concentrated H2SO4.
Flame atomic absorption spectrometric (AAS) analysis of the resulting
solutions revealed a linear increase of Mg, Zn and Cr concentrations
with the time of running the machine. This is consistent with the
normal wear of the moving parts of a machine and the loss of quality
of the lube oil with time. This trend is further confirmed by the
result of analysis of fresh lube oil samples from the same batch.
Unlike the other metals, Cu concentration was found to remain
practically constant in both used and unused samples, indicating this
element as an additive or a contaminant in the oil. This digestion
method was found to be fast (6 samples digested within 1 hour) and
effective in eliminating wear particle size effects commonly
encountered in this sort of study. An excellent precision was also
achieved (up to 0.2 %) through the obvious elimination of chemical
interferences and viscosity - induced inaccuracies often associated
with direct AAS analysis of oil samples.
KeyWords:
Lube
Oils, Wear Metals, Peroxymonosulfuric Acid, Aqueous Solutions, Atomic
Absorption Spectrometry.
Urea
fragments drug treated human erythrocytes by externalization without
temperature increase
A.
Nwafor
Department
of Human Physiology, Faculty of Basic Medical Sciences, College of
Health Science, University of Port Harcourt.
ABSTRACT
Application
of an appropriate amount of urea or urea with drug into a suspension
of human erythrocytes in microcapillaries incubated with or without
crenating or cup-forming drug in 5mM Hepes buffered saline, pH 7.4, at
room temperature (25oC), resulted in the incorporation of
urea into the membrane and induction of cell shape change of
echinocytic type and fragmented the cells by externalization without
causing haemolysis. The time to completion of urea induced cell
fragmentation by externalization phenomenon was not influenced by drug
concentration. It is suggested that urea was not an alternative to
heat for the study of drug membrane interaction when cytoskekeleton
are reduced. Based on these results, the effects of exposure of human
erythrocytes to urea environment are discussed.
Keywords:
urea- therapeutic use; fertilizer production environment, human
erythrocytes, Running title: Erythrocyte shape change induced by urea.
Optimum
size distribution of sorghum grist for brewing purposes
Benjamin
R. Etuk and Ifreke S. Akpan
Department
of Chemical/Petroleum Engineering
Department
of Brewing Science and Technology, University of Uyo, Uyo, Nigeria
ABSTRACT
The
effect of particle size distribution of malted sorghum grist on
extract yield and lautering performance was assessed. Sorghum grist
particle size evaluation was carried out by sieve analysis after
milling. The malted sorghum grist with proportions of coarse, fine,
and flour particles in the ratio of 0.36: 0.25: 0.39 respectively gave
good results in terms of extract yield and filtration rate. The values
of 103.05% and 1.42 x 10-4 m3/s were
obtained for extract yield and filtration rate respectively.
Keywords:
Size distribution, Filtration rate, Brewing
Geothermal
gradients in the Niger Delta basin from continuous temperature logs
O.
Akpabio,
Department
of Physics, University of Uyo, Uyo, Nigeria
J.
E. Ejedawe,
Exploration
Department, SPDC, Port Harcourt, Nigeria
J.
O. Ebeniro
Department
of Physics, University of Port Harcourt, Nigeria
and
E. D. Uko
Department
of Physics, University of Science and Tech, Port Harcourt, Nigeria
ABSTRACT
Subsurface
temperatures obtained from continuous temperature logs in 260 wells
allowed to stabilize for several months were used in determining the
geothermal gradients in the Niger Delta. Regional gradients are lowest
(0.82oC/100m) at the central part of the Delta and
increases both seaward and northward up to 2.62oC/100m and
2.95oC/100m respectively in the continental sands of the
Benin formation. In the marine paralic deposition, geothermal
gradients range from 1.83oC/100m to 3.0oC/100m
at the central portions. The highest values of 3.5oC/100m
to 4.6oC/100m are seen northwards while intermediate values
of 2.0oC/100m to 2.5oC/100m are recorded
seaward. The thermal gradients are clearly influenced by the lithology
or rate of sedimentation in the area. Regions of low thermal gradients
correspond with areas of high sand percentage, primarily because sands
are better conductors than shale and therefore show as low thermal
gradients. There is a continuous but non-linear relationship between
geothermal gradients and depth, from less than 1.0oC/100m
in the continental sands through 2.5oC/100m in the marine
paralic section to 5.0oC/100m in the continuous shaly
section.
Key
words:
Geothermal gradient, temperature, sand percentage, heat flow
Comparison
of two views on the structure of ionospheric currents
C.
A. Onwumechili and P. O. Ezema
C.
A. Onwumechili, 4813 Lackawanna Street, College Park, Maryland
20740,U.S.A.
P.
O. Ezema, Dept. of Physics & Astronomy, University of Nigeria,
Nsukka, Enugu State, Nigeria.
ABSTRACT
There
are two views on the structure of ionospheric currents, here
symbolized as VIEW 1 and VIEW 2. The essential difference between them
is that VIEW I supports the existence of two ionospheric current
layers in the dip equatorial zone as measured by many rockets
(Onwumechili,1992b,c). Contrary to the rocket measurements, VIEW 2
believes that ionospheric currents in the dip equatorial zone flow in
only one current layer. This paper presents 11 relevant experimental
results for explanations by VIEW 1 and VIEW 2 side by side. After
reviewing many papers on related topics and judging the performances
of the two views, it emerges that VIEW 2 is conjectural and has
feasibility problems. On the other hand, VIEW 1 is based on
observational results, and it simply and naturally explains the
experimental results.
Key
words:
ionospheric currents, current layers, magnetic dip equator, abnormal
phase quiet days, counter equatorial eletrojet.
Modelling
and characterisation of transistors
S.F.
Akande and B.J. Kwaha. Department of Physics, University of Jos, Jos.
A.M.
Batu, Department of Science Laboratory Technology, Kaduna Polytechnic,
Kaduna.
ABSTRACT
Models
and characterisation of active devices that control the flow of energy
operating within and outside the active region of the operating domain
are presented. Specifically, the incremental charge carrier and Ebers
Moll models of the bipolar junction transistor are presented and the
parameters of electrical behaviour of the device at the terminals were
measured and analysed. The parameters determined could be employed to
evaluate input and output impedances, current, voltage and power gains
of the device at appropriate operating points. The measured parameters
compare favourably with published manufacturers’ data to within 5%.
Keywords:
Modelling Bipolar Junction Transistor
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