bluuebunny/crossref_metadata_2025 huggingface dataset:
Foaming of Polystyrene/Supercritical CO2 in Rapid Decompression and Cooling Process
Authors: Wu Xiao Dan , Peng Yu Cheng
Published: March 2009

Foaming of polystyrene (PS)/ supercritical dioxide system was studied in a batch process in order to achieve a better understanding of supercritical CO2 diffusion mechanism in polymer and foaming condition. In this study, PS sample was treated with CO2 at 5-30 MPa and 40-160°C, soaking times was about 30-120min.Using gravimetric method, the solubility of CO2 in PS was obtained. The study datum shows that the solubility of CO2 in PS increases with increment of pressures, but decreases with the increment of temperature. The sorbed amount of CO2 is from 0.02 % (7MPa,160°C) to 0.11%(30MPa,40°C).The relation of glass transition temperature, volume expansion ratio, cells density of foaming with pressure and temperature also was discussed individually. The glass transition temperature of PS swelled with CO2 is 80°C-95°C, which is lower than the glass transition temperature of pure PS by 10°C-25°C. The cell density increases as the pressure increase, and it decrease as the temperature increase.
Application of Rubber Non-Rotating Drill Pipe Protectors in Drilling
Authors: An Ying , Yang Wei Min , Zhang Yang , Zhao Hui Qing
Published: March 2009

Using of rubber non-rotating drill pipe protectors is one of the most important technology measures to reduce the casing wear and rotary torque of drill pipe in case of drilling deep well, ultradeep well, extended reach well and horizontal well. This paper presents the operating principle of protectors, and investigates the effect on contact pressure with the using of protectors by finite element analysis (FEA). The results give out the theoretical foundation of reducing the casing wear and rotary torque of drill pipe by using rubber non-rotating drill pipe protectors.
Detoxification of Asbestos and Asbestos-Containing Cement Board
Authors: Hashimoto Shinobu , Honda Sawao , Awaji Hideo , Fukuda Koichiro
Published: March 2009

Mechanical destruction of acicular asbestos has been carried out as a process for
decontamination. The dehydration reaction of asbestos occurred at 600°C and has been completed for
2 h at that temperature. This dehydration reaction of asbestos led to weakening of the mechanical
properties of asbestos. After grinding, the microstructure of asbestos appeared no acicular shape.
Further, this technique could be applied to asbestos-containing cement board. The spent cement board
has about 10-20 mass% of asbestos (chrysotile: Mg3Si2O5(OH)4) and 5 mm thickness was used. After
heating at 600°C for 2 h and grinding, the microstructure of the sample also appeared no acicular
shape. Thus it was cleared that heating at 600°C and then grinding treatment for asbestos (chrysotile)
has a grate important effect of mechanical and chemical destruction of asbestos in both cases of free
asbestos and asbestos-containing cement board.
Cutting Process Monitoring by Means of Acoustic Emission Method; Part I - New Approach of Acoustic Emission Sensor; Part II - Transformation of Acoustic Emission into Audible Sound
Authors: Zizka Jan , Hana Petr , Hamplova L. , Motycka Z.
Published: March 2009

Development of modern society is converging to a status where many human actions can
be performed by machines. To achieve production without human intervention, machines require
artificial receptors. Data gathering for processing and analysis of signals, together with
determination of feedback reactions can be achieved by a suitable decision maker unit. A sensed
value suited to this so-called intelligent sensing process would be the acoustic emission signal. In
the case of intelligent cutting tools this would require miniature highly sensitive sensors integrated
into the cutting tool body. Part I of this paper deals with the possibility of practical usage of the
piezoelectric properties of copolymer foils for the acoustic emission sensor as a transducer of a
mechanical surface wave into electrical signal. Part II of the paper deals with the most fundamental
requirement for monitoring of cutting conditions during machining, i.e. excellent processing of
measured data. Data obtained from machining process obtained by means of acoustic emission
sensors, as discussed in the first part of this article, have high-frequency and continuous character of
a white noise. These data are very difficult to process. New apparatus for transformation of acoustic
emission into audible sound in the workplace is presented. The first stage of processing is by
listening to transformed data it is subjectively possible to recognize differences in audible spectrum,
corresponding to different states of the cutting tool. The second step is visualization of the
differences via the fast Fourier transform (FFT) in the spectrum graphic chart.
A Practical Investigation into Acoustic Wave Propagation in Concrete Structures
Authors: Norazura Muhamad Bunnori , Pullin Rhys , Holford Karen M. , Lark R.J.
Published: March 2009

Acoustic Emission (AE) testing in concrete structures shows great potential for
monitoring and assessing the health condition of structures. Source location is normally based on
the arrival times of transient signals, the simplest method is known as the Time of Arrival (TOA)
method, where the location of the damage can be determined from the arrival time of the event at
two or more sensors. When using this method, the wave velocity of the signals that propagate
through the material needs to be determined. Homogenous materials, such as steel, have welldefined
velocities, but in non-homogeneous materials such as concrete the wave velocity is more
difficult to predict. This makes the use of a single wave velocity as required in the TOA method
very difficult due to the variety of wave velocities obtained, especially for large structures.
This paper explores wave propagation in concrete structures over a variety of source to sensor
distances. Experiments were performed on a reinforced concrete beam and a reinforced concrete
slab, using an Hsu-Nelsen (H-N) Source. It is found that, in general, as the source to sensor distance
increases, the wave velocity decreases. The presence of longitudinal and transverse waves is
demonstrated and the influence of the part of the waveform used for temporal measurement is
explored. In order to provide a practical approach to velocity determination, different thresholds are
investigated and the results are discussed in relation to the wave modes present.
Acoustic Emission Monitoring of Al Corrosion in Cemented-Based Wasteforms
Authors: Spasova L.M. , Ojovan M.I. , Scales Charlie R.
Published: March 2009

An acoustic emission (AE) technique has been employed for nondestructive monitoring
of the performance of a laboratory scale cementitious wasteform encapsulating Al. Recorded AE
activity revealed the possibility for classification and differentiation of detected AE signals with a
potential relationship between the corrosion rate of encapsulated Al and the accumulated structural
damage within the cement matrix.
Determination of Damage Levels of Composite Plates after Low Velocity Impacts Using Acoustic Emission
Authors: Bradshaw Timothy P. , Eaton Mark J. , Pullin Rhys , Evans S.L. , Featherston C.A.
Published: March 2009

Eight composite plates 400x410x2.15mm were fabricated from carbon/epoxy in
((0,90)4)s lay-up. To ensure there was no damage in the plates prior to the impact investigations the
plates were C-scanned. A drop test rig was used to apply a low velocity impact to the undamaged
plates. A rebound mechanism was employed to prevent secondary impacts.
AE sensors were selected for frequency and size due to the limited space on the test rig. Super
glue was used both as a couplant and also to secure the sensors in position. During the impact wave
streaming, time driven data and hit driven data were used to record the impact simultaneously. One
test was conducted on each sample with two impacts completed at 5J, 6J, 8J and 10J (total of 8
samples). The impacts were designed to allow only slight visible impact damage to be formed.
After completion of the impact investigation the plates were C-scanned to determine the area of
debonded material. Analysis of the data showed the complete record of the impact event from the
wave streaming, while the hit driven and time driven absolute energy data provided increasing
correlations with the area of composite damaged.
Acoustic Emission Monitoring of Defects in Buckling CFRP Composite Panels
Authors: Eaton Mark J. , Holford Karen M. , Featherston C.A. , Pullin Rhys
Published: March 2009

The presence of impact damage in a carbon fibre composite can reduce its capacity to
support an in-plane load, which can lead to an unexpected or premature failure. This paper reports
on an investigation into two slender carbon/fibre epoxy panels, one un-damaged and one with an
artificial delamination introduced using an embedded section of PTFE. The reported tests form part
of a larger series of investigations using differing sizes of artificial delamination and real impact
damage. An investigation of wave velocity propagation at varying angles to the composite lay up
was completed to assist in source location. The specimens were loaded under, uniaxial in-plane
loading and monitored using four resonant acoustic emission sensors. A full field optical
measurement system was used to measure the global displacement of the specimens. Analysis of
AE waveforms and AE hit rate were used to assess the buckling of the panel. The results compared
favourably with the optical measurement results.
Acoustic Emission Testing of High-Pressure Composite Cylinders
Authors: Bohse Juergen , Mair Georg W. , Novak Pavel
Published: March 2009

AE studies were performed considering pressure cylinders of design1 Type II – metallic
liner with hoop composite wrapping, Type III – metallic load sharing liner with full composite
wrapping and Type IV – all-composite cylinder. The AE technique has to be improved so far that
for different design types of cylinders standard AE equipment can be used in an easy and
practicable way under normal conditions of production and service. The paper presents our 8 years
of experience in this application area using conventional AE measuring technique. Potentials,
requirements and limits for detection of manufacturing faults and in-service damages of highpressure
composite cylinders are discussed.
1Cylinder types classification in accordance with ECE R 110 / ISO 11439
Embedded Code Processing for the On-Line Use of User-Developed AE Analysis Routines
Authors: Vallen Hartmut , Vallen J. , Forker J.
Published: March 2009

In spite of the availability of very versatile analysis packages, such as VisualAE™, the
large variety of test objects that can be successfully tested by AE sometimes calls for the use of an
application dedicated analysis algorithm, especially if large numbers of similar or identical objects
shall be tested.
This can save a lot of time for data analysis and interpretation and reduce the requirements on
operator qualification.
Those analysis algorithms can be developed by AE-experts based on AE data from a number of
test objects. Up to now, such a program had no access to real time data.
The more such a dedicated analysis
algorithm proves to be helpful and valuable
for a specific application (e.g. testing small,
buried LPG vessels), the higher the desire to
use that algorithm also in real time (i.e.
during data acquisition). This can simplify
testing and improve test control e.g. by the
application of higher sophisticated alarm
criteria.
With the new Embedded Code Processor
(ECP) the user can develop and verify
software algorithms of any complexity, that
run within the environment of VisualAE™.
This tremendously accelerates the
implementation process.
Any result within VisualAE can be input
into the user-developed code, any new
results can be calculated, and then used by
VisualAE for filtering, data presentation and
alarm raising, if desired in combination with
the conventional results.
This paper summarizes the structure of
VisualAE in short and the intentions and
possibilities of an Embedded Code
Processor (ECP).
ECP is already available and in use.
Diagnosis of Artificial Gear Defects on Single Stage Gearbox Using Acoustic Emission
Authors: Loutas Theodoros , Kalaitzoglou J. , Sotiriades G. , Kayias E. , Kostopoulus V.
Published: March 2009

Acoustic Emission is a very powerful tool for health monitoring of structures and
mechanical components, especially due to its sensitivity, which is very useful at the early stages of
damage evolution. Evaluation of its potential on rotating structures such as gearboxes, is studied in
the present paper. A new concept of transducer mounting is realized in a single stage in-house built
gearbox. The acoustic emission signature of the healthy gears is acquired. Then artificial defects are
seeded and the acquisition is repeated. The signals are afterwards analyzed and the assessment of
the applicability of the method becomes possible. Given the present experimental setup, health
monitoring of gearboxes using acoustic emission is considered to be of rising potential.
Acoustic Emission for the Detection of Shaft-to-Seal Rubbing in Large Power Generation Turbines
Authors: Leahy Mark John , Mba D. , Cooper P. , Montgomery A. , Owen D.
Published: March 2009

An empirical investigation is undertaken in order to assess the potential of the AE
technique for the detection of seal-to-rotor rubbing in steam turbines. Rubbing was induced at
various axial locations along a 4 ½ tonne test rotor, rotating at 3000 rpm and supported by 7”
(178mm) journal bearings. This paper examines the capabilities of bearing mounted AE transducers
for the detection of seal-to-rotor rubbing.
Acoustic Emission Source Location Based on Signal Features
Authors: Blahacek Michal , Chlada M. , Prevorovský Z.
Published: March 2009

Good knowledge of acoustic emission (AE) source location is the basic requirement for
further damage mechanism characterization. Calculation of the AE source location is mostly based
on arrival time differences of the signals recorded by different transducers. Error free arrival time
determination is the crucial factor for the localization results accuracy together with the exact
elastic wave velocity measurement. In the paper difficulties and limitations of the elastic wave
velocity computation are shown. To solve the velocity and the time differences problems, new
approach to AE source localization is described. The new method estimates the AE source
coordinates using artificial neural network (ANN) processing extracted signal parameters. The
ANN do not uses neither arrival time differences nor elastic wave velocities as input data. The new
approach advantages are discussed in cases of both numerical and practical experiments. The
experiments results are promising for the use of designed localization method in praxis.
Wavelet Transform and Bispectrum Applied to Acoustic Emission Signals from Adherence Scratch-Tests on Corroded Galvanized Coatings
Authors: Gallego Antolino , Gil Jose F. , Vico J.M. , Díaz Barriga-Castro Enrique , Ruzzante J.E. , Piotrkowski Rosa
Published: March 2009

Wavelet analysis and bispectrum was applied to Acoustic Emission (AE) signals from
scratch tests on corroded hot-dip galvanized samples in order to achieve the detection of corrosion
products in pieces non reachable by visual inspection. AE signals were correlated with the fracture
mechanisms occurring during scratch tests, while the contact force increased. Results were
corroborated by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy
(EDX) and X-Ray Diffraction (XRD).
Development of Degradable Fe-35Mn Alloy for Biomedical Application
Authors: Hermawan Hendra , Dubé Dominique , Mantovani Diego
Published: March 2009

As some biomedical problems require only temporary intervention, there is a clinical
need for degradable biomaterials with excellent mechanical properties and controllable degradation
behaviour. Although several works were carried out on both polymeric and metallic materials, no
proposed degradable biomaterial fully satisfied these requirements. Therefore a new Fe-35Mn alloy
has been developed as a valid and well suited alternative. The alloy was fabricated through powder
metallurgy route followed by successive cold rolling and sintering cycles. This austenitic alloy
exhibits a high strength and ductility, comparable to that of type 316L stainless steel. Its
antiferromagnetic behaviour is not changed by cold deformation process. The alloy shows suitable
degradation behaviour with a uniform corrosion mechanism and a slow release of ions that make it
particularly well suited for the development of a new class of biodegradable stents.
Cavitation Erosion Resistance of WC-Cr-Co and Cr3C2-NiCr Coatings Prepared by HVOF
Authors: Zhang Ping , Jiang Jing Hua , Ma Aibin , Wang Ze Hua , Wu Yu Ping , Lin Ping Hua
Published: March 2009

With the aim to obtain the high cavitation-erosion-resistance coating for the surface
safeguard of fluid machinery, two kinds of hard coatings (WC-Cr-Co and Cr3C2-NiCr) were
prepared on 1Cr18Ni9Ti substrate by high velocity oxy-fuel spraying (HVOF), which
microstructure and performance were investigated respectively by optical microscope, X-ray
diffraction, Vickers hardness, scanning electron microscope (SEM), and vibratory cavitation
apparatus. The results indicated that these two coatings had the higher hardness and the finer
structure than ZG06Cr13Ni5Mo, which is used actual in water conservancy. The results of
cavitation erosion continued for 39 hours presented that the mass loss of WC-Cr-Co and Cr3C2
-NiCr coatings increased ceaselessly with time, and the cavitation erosion speeds varied with time.
Compared with ZG06Cr13Ni5Mo, their cavitation erosion resistance performances were better due
to their higher hardness and finer structure, and WC-Cr-Co coating was much better than
Cr3C2-NiCr coating. Obviously, the higher hardness and finer structure could strengthen the
cavitation erosion resistance of coating materials.
Joint Characteristics of Spot Friction Stir Welded 5052 Al Alloy Sheet
Authors: Lee Chang Yong , Lee Won Bae , Yeon Yun Mo , Song Keun , Moon Jeong Hoon , Kim Jung Gu , Jung Seung Boo
Published: March 2009

The microstructure and mechanical properties of spot friction stir welded A 5052 alloy
were investigated with insertion depth of welding tool. As the insertion depth of welding tool
increased, the size of stirring zone increased and the thickness of upper sheet decreased. The value of
shear load was the lowest at the shallowest insertion depth and increased to the highest value of 3.35
kN at a 1.6mm of insertion depth. An increase in the pin insertion depth beyond 1.6mm did not result
in further increase in the lap shear load. Spot friction stir welded joints showed shear fracture mode at
shallower insertion depths and fracture mode changed to plug fracture mode as the insertion depth
was deeper.
Dissimilar Metal Welding of Steel to Al-Mg Alloy by Spot Resistance Welding
Authors: Hwang I.H. , Watanabe Takehiko , Doi Y.
Published: March 2009

We tried to join steel to Al-Mg alloy using a resistance spot welding method. The effect
of Mg in Al-Mg alloy on the strength and the interfacial microstructure of the joint was investigated.
Additionally, the effect of insert metal of commercially pure aluminum, which was put into the
bonding interface, on the joint strength was examined. The obtained results were as follows. The
cross-tensile strength of a joint between SS400 steel and commercially pure aluminum (SS400/Al)
was high and fracture occurred in the aluminum base metal. However, the strength of a joint
between SS400 and Al-Mg alloy was remarkably low and less than 30% of that of the SS400/Al
joint. An intermetallic compound layer developed so thickly at the bonded interface of the
SS400/Al-Mg alloy joint that the joint strength decreased. The intermetallic compound layer
developed more thickly as Mg content in the Al-Mg alloy increased. Using insert metal of
commercially pure aluminum containing little Mg successfully improved the strength of the
SS400/Al-Mg alloy joint and the strength was equivalent to that of the base metal.
Influence of Heat Treatment on Structure and Properties of the Cast Magnesium Alloys
Authors: Tański Tomasz , Dobrzański Leszek Adam , Čížek Lubomír
Published: March 2009

In this paper is presented the structure and proprieties of the cast magnesium alloys as
cast state and after heat treatment cooled with different cooling rate, depending on the cooling
medium (furnace, water, air). For investigations samples in shape of 250x150x25 mm plates were
used. The presented results concern X-ray qualitative and quantitative microanalysis as well as
qualitative and quantitative X-ray diffraction method, tensile tests, hardness measurement. In the
analysed alloys a structure of α %solid solution and fragile phase β (Mg17Al12) occurred mainly on
grain borders as well as eutectic and phase AlMnFe, Mg2Si. Investigation are carried out for the
reason of chemical composition influence and precipitation processes influence to the structure and
mechanical properties of the magnesium cast alloys with different chemical composition in as cast
alloys and after heat treatment.
Phase Decomposition in Isothermally Aged MA Cu-Ni-Fe and Cu-Ni-Cr Alloys
Authors: Hernandez-Santiago Felipe , Espinoza-Ramirez I. , Victoria-Hernández V.M. , Saucedo-Muñoz M.L. , Díaz-Barriga Arceo Lucia , Dorantes-Rosales H.J.
Published: March 2009

Supersaturated solid solutions of Cu-44.5at.%Ni-22.5at.%Fe and Cu-37at.%Ni-6at.%Cr alloy were
produced by ball milling of a pure chemical elemental mixture for 1080 ks. Two fcc supersaturated
solid solutions with a grain size of about 20 and 50 nm, respectively, were obtained after milling.
These alloys were subsequently aged at temperatures between 800 and 1003 K for different times.
The aging promoted the phase decomposition of the supersaturated solid solution into a mixture of
Cu-rich and Ni- phases in both the aged MA alloy powders. The growth kinetics of the modulation
wavelength was determined from the X-ray diffraction results and followed the Lifshitz-Slyozov-
Wagner theory for a diffusion-controlled coarsening in the mechanically-alloyed Cu-Ni-Fe alloy
after aging. However, the sidebands intensity seems to be very low and overlapped with the peaks
corresponding to the Cu-rich phase in the aged mechanically-alloyed Cu-Ni-Cr alloy. The growth
kinetics of composition modulation wavelength for the aged MA Cu-Ni-Fe alloy was faster at 803
and 898 K than that for the same alloy composition obtained by a conventional processing and then
aged at the same temperatures.
Effect of Second Phase on Mechanical Properties of Bainite-Base Steels
Authors: Lee Hak Cheol , Wu Xiao Dan , Kim Young Min , Kim Nack
Published: March 2009

Effects of acicular ferrite and retained austenite on the mechanical properties of
bainite-base steels were investigated. Various morphology and volume fraction of constituent phases
have been obtained by control of hot rolling conditions and alloy compositions. It has been shown that
the steels containing retained austenite have better combinations of strength and ductility than the
ones with no retained austenite. However, there is no noticeable change in DBTT by the incorporation
of retained austenite in the microstructure since retained austenite exists as fine particles. On the other
hand, DBTT of the steels are largely affected by the presence of acicular ferrite in the microstructure.
EBSD analyses of fractured Charpy specimens show that cracks are deflected within the
morphological packet of acicular ferrite, indicating its role in reducing the effective grain size of the
steels.
Microstructure - Texture Related Toughness Anisotropy of API-X80 Pipeline Steel
Authors: García Orlando León , Petrov Roumen H. , Bae Jin Ho , Kestens Leo A.I. , Kang Ki Bong
Published: March 2009

The dependence of Charpy toughness on the microstructure and texture of two industrial
grades of API –X80 pipeline steel with a thickness of 15 and 17 mm, respectively, were studied in
this work. Standard size Charpy samples with a long axis orientated at 0, 22.5, 45, 67.5 and 90°
with respect to the rolling direction of the plate were tested at different temperatures varying from
-196°C to 20°C. Microstructure and texture of the plates were studied by means of electron backscattering
diffraction (EBSD) and XRD. The highest value of the absorbed energy (440 J) was
measured at room temperature in the samples oriented with the long axis parallel to the rolling direction
and the minimum values for the same temperature were observed in the samples enclosing
an angle of 45° to RD (340J). Statistical model parameters obtained from Charpy impact tests were
quantitatively correlated to microstructural parameters by means of a linear regression model with
the aim to describe the Brittle-Ductile Transition Curve in terms of microstructural features. Based
on dedicated experiments the Brittle Fracture Factor (BFF) parameter was introduced, which quantifies
the fraction of the {100} planes oriented parallel to the crack propagation front. It was found
that the Charpy toughness anisotropy of the plates in the lower shelf region can not be related only
to their crystallographic texture, but to the microstructural anisotropy characterized by the grain size
variations i.e. the density of grain boundaries in the different directions. Also the spatial distribution
of the 2nd phase plays a determining role in the fracture behavior.
Elimination of Frequent Electric Power Interruption Due to Lightning Discharge in Nigeria
Authors: Usifo F.O. , Oria Usifo Eromosele
Published: March 2009

The problems facing the Power Holding Company of Nigeria PLC (PHCN) which was
formerly called the National Electric Power Authority (NEPA), are numerous to the extent that
every power electric engineer both in the industrial sector and in academic is being challenged
to proffer possible solutions. In an attempt, to combat some of these problems, this paper is
therefore focused on a problem, affecting frequent power interruption to consumers during rainy
season by PHCN. A research carried out before now ascertained that more than 500 hours were
lost annually on power interruptions due to lightning discharge in various substations throughout
the country during rainy season. Therefore, this paper has suggested the use of double lightning
arresters instead of one, for the protection of industrial and domestic electrical installation work.
It recommended the use of Thyrite or Oriaghe low voltage lightning arrester to prospective
power consumers for domestic application. Also, for the high voltage protection it
recommended the use of the high voltage Thyrite lightning arrester for lightning discharge
protection of transformers and switch gears, used by PHCN.
Management of Existing Capacity of Electric Power with Energy Saving Devices
Authors: Ekeh J.C. , Wara S.T. , Orovwode H.E
Published: March 2009

The strategy of management of the existing capacity by proper illumination design and
the use of energy saving devices in the residential sector is reported. Improper installation design
and the use of all sorts of devices at homes has led to a lot of electrical energy wastages resulting in
the need to increase the generation capacity. The study revealed that annual energy of 551.88kWh
could be saved for a three – bedroom flat when energy saving fluorescent lamps were used. The
corresponding naira savings was 2,207.52 per annum. In addition, the sizes of cable, fuses/circuit
breakers required are reduced and hence reduction in the cost of installation. The paper advocates
the need for proper design and installation of energy saving devices in homes. The paper will be of
relevance to lighting installation designers, power systems engineers, power utility managers, and
the general public.
Broadband Cordect: Technology for Building Knowledge Societies
Authors: Santhi K.R. , Anand P.M.Rubesh , Kumaran G. Senthil
Published: March 2009

The Internet has emerged in the last few years, not just as another communication means,
but as sheer power and access to it provides access to a lot of information. Lack of access to internet
will bring strong digital divide between rich and poor countries and also brings strong divide within
the rural and urban communities of a country which in turn will affect the socio- economic
development of a country. So there is a need for low-cost information technologies that are suitable
to the conditions prevailing in a developing or third world country. Broadband CorDECT is one of
the cost-effective fixed wireless broadband Access Solutions used for networking and building
knowledge societies in a developing country. It is based on the DECT standard specification from
the ETSI. It provides a complete wireless access solution for new and expanding telecommunication
networks with seamless integration of both voice and internet services. It has been designed and
specified to inter-work with many other types of network, such as the PSTN, ISDN, GSM and more.
Broadband CorDECT provides the basic telecommunications as well as broadband Internet services
and thus bridges the digital divide and such a service cannot be provided by any other product today
in the world even double the cost. This paper discusses the relevance of broadband CorDECT in the
context of current trends and provides a description of the technology.
Effect of Temperature and Total Solid Contents on the Apparent Viscosity of Coconut Milk Yoghurts
Authors: Mepba H.D. , Ademiluyi T.
Published: March 2009

Procedures for the preparation and rheological characterisation of coconut
milk yoghurts are described. Coconut milk was fortified with soymilk, 50:50 (v/v/)%
(coconut milk:soymilk), Nonfat dry milk, 60:40 (coconut milk:Nonfat dry milk), while
whole coconut milk served as control. Milk preparations were homogenized, heated to
40, 60 and 80oC for 30 mins, inoculated with Streptococcus thermophilus and
Lactobacillus bulgaricus and incubated at 43oC to attain pH 4.6. Rheological properties
of yoghurts were studied at temperatures ranging from 10 – 80oC. All samples
exhibited a pseudo plastic behaviour and described by a power law model. The effect
of temperature on apparent viscosity was explained by a polynomial equation and gave
a better fit than the Arrhenius relationship. The consistency coefficient exhibits strong
dependence on temperature for which the activation energy of flow ranged from 4.57–
6.47kJ/mol. The flow behaviour index was low and nearly constant (~ 0.78) up to 40oC
and then decreased with further increase in temperature.
The Effects of Detergent on the Microbiological Changes of Fermenting Cassava for Fufu Production
Authors: Aisien E.T. , Aisien F.A.
Published: March 2009

The effects of detergent on the microbiological changes of cassava for fufu production
were investigated for a period of 72hr. Microbiological analyses of the fermenting cassava samples
using standard methods were carried out. Six microbial species: Lactobacillus plantarum,
Citrobacter freundii, Corynebacterium manihot, Lactobacillus cellobioscus, Pseudomonas
alcaligens, and Leuconostoc mesenteriods were identified for the control. The same organisms were
identified for the low detergent concentrations (1g/L, 2g/L) except Corynebacterium manihot,
Leuconostoc mesenteriods, which were completely destroyed. High detergent concentrations (4g/L,
8g/L) inhibited the growth and subsequently killed all the organisms living very few Citrobacter
freundii behind. At low detergent concentrations the cassava ferment within 48hr without
objectionable odour. However, at high detergent concentrations there was no fermentation even
after 72hr. The control samples fermented after 72hr with undesirable odour.
Determination of Physicomechanical Properties of Cowpeas to Aid Thresher Design
Authors: Maunde F.A. , Ali M.A. , El Okene A. , Riji B.B.
Published: March 2009

Two varieties of cowpea namely indigenous brown (Variety A) and RMP- 12
(Sampea -10) white (Variety B) were collected and their Physicomechanical properties were
determined. The results of moisture content, sizes and mass of pods and seeds were { (6.5 % &
6.8%), (5.5 % & 6.0 %)}, { (150 mm & 130 mm), (9 mm & 10 mm)} and {(1.8g & 2.0 g ),(
0.9g & 0.8 g)} respectively. Other results found were particle density, angle of repose,
coefficient of friction , hardness and shape/ sphericity of seeds and pods were {(280g & 376 g),
(287 g & 275g ) }; {(39o & 36o ), (29.6o & 30 .9o)} {(0.58 & o.63), (0.42 & 0.41)}; {(5N &
5N), (9N & 8.5 N) and {66 % & 69 %) , (79 % & 75 %)} respectively. The F- 0 values
obtained for the varietal differences were found less than those in the F- Table at 5% level of
confidence, which signified the non existence of significant differences between the varieties.
The physicomechanical properties were used for the design of a motorized cowpea thresher.
Development of a Moisture Measuring Device for Cassava Particulate during Drying
Authors: Ogunleye I.O. , Adeyemo S.B. , Adeyemi M.B.
Published: March 2009

A moisture-measuring device for the determination of percentage moisture content of
cassava particulate on dry basis during drying process was developed used to investigate the effect
of pressure on the resistance of the cassava particulate sample. A thermo-gravimetric sample
analysis was used for the calibration of the moisture measuring device. The device had four
electrode cups, two of which were used as dummies to give a ½ Wheatstone bridge circuit used to
measure the resistance. The resistance of the cassava samples increases with decrease in the
%moisture content and decreases with increase in pressure.
Investigation of Force Required to Crack Melon Seed Shell by Static Loading
Authors: Okokon F.B. , Oduh Mathew A. , Akpan N.A.
Published: March 2009

The force required to shell melon seed by static loading techniques was investigated with
an experimental rig machine. Melon seeds were categorized based on their moisture content into 4
sub-samples by soaking. Ten seeds from each sample were randomly selected and loaded in three
different loading orientations x, y and z. The mean force required to crack the seeds was
determined. Results showed variations in force, while analysis of variance showed significant
difference in the loading orientation and no significant difference in the interaction of moisture
content, at 95% level of confidence.
Effect of AISI316 Stainless Steel Geometry on Temperature Distribution during Hot Rolling at High Reduction
Authors: Alamu O.J. , Aiyedun P.O. , Kareem A. , Waheed M.A.
Published: March 2009

The effects of material geometry on some rolling parameters have been studied. In a
recent work, geometrical variation was introduced into the Reverse Sandwich Rolling Model
(RSM) for AISI316 Stainless Steel (HCSS316) to study the effect of ingot geometry on
temperature distribution during hot rolling. Validation of the model was however limited to hot
rolling simulation at low reductions. In this work, the RSM, simulated in FORTRAN, is
validated with hot rolling experimental data for higher reductions. Results obtained revealed a
similar pattern of symmetrical temperature distribution from the rolling surfaces, to the midthickness
of the material as earlier observed at low reductions.
Strength Study of Concrete Made with Various Local Sands in Benin City, Nigeria
Authors: Alutu O.E. , Ifejika B.K.
Published: March 2009

The paper focuses on the effect which varying the type of sand used in concrete will have
on the compressive strength of concrete and seeks to determine the suitability of each sand for use
in concrete works. The sand samples used include Okhoro, Ikpoba, Ovia and Okhuahiaerosion
sands and Ikpoba, Ovia and Okhuahia river sands. Particle size distribution of the sands was first
determined and the result was used to design grades 20, 25, and 30 concretes to Department of
Environment (DOE) mix design method. Twelve cubes were cast from one particular sand sample
and three cubes were tested at 7, 14 and 28 days for each grade of concrete respectively .The result
revealed that the sand samples that are well graded gave the highest compressive strength; while the
poorly graded sands gave lower strengths. Okhuahia river sand gave the strongest concrete followed
by Ikpoba, and Ovia river sands, Okhuahia, Ikpoba, Ovia and Okhoro erosion sands. Particle size
distribution within a sand zone probably did not affect strength but the impurity content did.
However, the inter-zonal differences in particle sizes probably did affect strength. The result also
showed that only the river sands and Okhuahia erosion sand are good for concrete making.
Rubber Seed Oil-Based Polyurethane Composites, Fabrication and Properties Evaluation
Authors: Okieimen F.E. , Bakare I.O.
Published: March 2009

Polyurethane samples were prepared from rubber seed oil monoglyceride (made by
reacting rubber oil with glycerol) and diiosocyanates (hexanethylene and toluene diiosocyanates).
Polyurethane composites were made by compression moulding using biofibres; sisal, jute and
banana; in random and unidirectional orientations at different fibre lengths and loadings, as
reinforcing elements. The composites were characterized in terms of tensile and flexural strengths
and moduli, thermal stability and morphology of fractured surface. The values of the measured
mechanical properties (tensile and flexural) of the composites were about 3-fold higher than the
properties of the unreinforced polyurethane samples, suggesting good reinforcement by the
biofibres. The absence of fibre-pull-out on the scanning electron micrographs of the fractured
surface provides evidence in support of good adhesion between the biofibres and the polyurethane
matrix. The thermal stability of the composites was lower than for the fibre but higher than for the
unreinforced polyurethane.
Effect of CacO3 and Wood Flour Filler on the Compression Strength of Coconut (Coir) Fibre Reinforced Polymer (FRP) Composite
Authors: Inegbenebor Anthony O. , Ogbevire A.D. , Inegbenebor A.I.
Published: March 2009

Compression test specimens were produced from the composite material of fibre
reinforced polymer (FRP). These specimens were tested on the compressive testing machine.
The results obtained showed that 5% coconut fibre volume fraction with 95% volume fraction
of polypropylene matrix gave compressive strength value of 39.3 Mpa. However, it was
observed that when 15% volume fraction of CaCO3 and wood flour filler each were added, the
compressive strength increased from 39.3 Mpa to 53.3 Mpa and 39.3Mpa to 43.7Mpa
respectively. This observation was discussed in respect of the two fillers.
Model Development of the Application of Finite Element – Eigenvalue Method to the Determination of Transient Temperature Field in Functionally Graded Materials
Authors: Akpobi John A. , Edobor C.O.
Published: March 2009

In this paper, a finite elment-eigenvalue method is formulated to solve the finite element
models of time dependent temperature field problems in non-homogeneous materials such as
functionally graded materials (FGMs). The method formulates an eigenvalue problem from the
original finite element model and proceeds to calculate the associated eigenvectors from which the
solution can be obtained. The results obtained highly accurate and are exponential functions of time
which when compared with the exact solution tended fast to the steady state solution.
Utilization of Calcite and Calcite-Cement in the Stabilization of Laterites for Low-Cost Hollow Blocks
Authors: Alutu O.E. , Ihimekpen M.O.
Published: March 2009

This paper examines the production of calcite and calcite-cement stabilized
laterite hollow blocks as low-cost masonry units. First, is the production of laterite hollow
blocks solely stabilized with finely ground limestone or calcite followed by the production of
laterite hollow blocks stabilized with calcite-cement composite. Laterite was sourced from
three locations: Asoro, Evbuotubu and Ugbowo. Blocks were produced using a specially
constructed machine with percentages of calcite and calcite-cement content varying from
4% to 16% respectively at compactive pressures of 10.32 and 13.75N/mm2. Equal
amounts of calcite and cement are used in the composite. The blocks were then tested for
7, 14 and 28 days strengths after curing. The results show that laterite blocks stabilized
with calcite alone do not satisfy the Nigerian Industrial Standards or British Standards for
blocks but those stabilized with 8% calcite-cement content, i.e., 4% calcite with 4% cement
do, at moulding pressure of 13.7 N/mm2. Based on the local cost data, the results also
show that calcite-cement stabilized laterite hollow blocks are 17% cheaper than an
equivalent cement-stabilized hollow block and 46% cheaper than the low quality sandcrete
blocks sold in the market.
Innovative Solutions to Fines Management in High Permeability Sands
Authors: Oyeneyin Babs Mufutau , Mufarji Said , Igwegbu Donald
Published: March 2009

Formation impairment due to fines migration during drilling and production continues to
cause injectivity or inflow reduction. In high permeability sandstone formations or sandpacks, fines
migration pose major concerns in the oil industry as it leads to reduction in oil/gas production. The
problem is further enhanced in mature reservoirs where increased water ingress and multiphase
production aggravate the fines mobilisation and migration. Proper fines management can optimise
productivity, safeguard facilities and reduce well maintenance cost. Today’s core flood tests as part
of risk assessment limit tests to single phase or at best two-phase oil/water flow. This paper presents
the unique technique adopted to analyse fines migration mechanisms in a true multiphase
environment. The technique integrates CFD and 3-D reservoir simulation concepts to define and
quantify the effects of different operating conditions on discretised reservoir blocks. From the
results obtained detailed mapping of prevailing pore blocking mechanisms and corresponding
impairment profiles are presented as functions of operating conditions and completion strategies.
The paper introduces a parallel experimental programme being initiated at The Robert Gordon
University(RGU) to validate the simulation predictions. The paper is concluded with suggestions
(supported by flow efficiency case studies) on contemporary innovations in fines management
ranging from a radical use of expandable screens (ESSTM) or expandable slotted liners (ESLTM) or
the intelligent VSSTM Screen to specialist application of glass or ceramic beads for pore diameter
control and near wellbore reinforcement to initiate secondary filtration
Potentials of Passive Solar Design in Energy Conservation in Buildings in the Warm Humid Climate
Authors: Okereke P.A. , Odim Odim O.
Published: March 2009

The achievement of energy efficiency in the building sub-sector is considered a very
important issue in contemporary research and development efforts by engineers, architects and
environmentalists. This is because of its direct impact on national economies and indirectly on the
environment and the general well being of future generations. This paper attempts an evaluation of
the potentials of passive design in the warm humid zone of Nigeria by assessing the level of energy
conservation in building through solar orientation. Model experimental buildings were constructed
and comfort factors (indoor and out door temperature, relative humidity, solar radiation, etc)
measured, and the climatic and technical (construction) factors determined for each of the model
buildings using known methods. Regression model on the effect of solar radiation on the climatic
and technical factors reflecting the amount of heat energy required to achieve an acceptable
comfort level for each building was formulated. Results from the study show that there is strong
evidence of tremendous potentials in passive design as ecotechique for energy conservation in
buildings.
Susceptibility of Clay Core to Cracks in Rockfill Dams by Finite Element Modeling
Authors: Osuji S.O. , Anyata B.U.
Published: March 2009

The behaviour of the core of rockfill dam with slanting clay core was investigated with
the Jebba main dam, Nigeria as a case study. The stress-deformation behavior of the dam was
studied using the finite element mathematical modeling technique. The actual fill properties were
utilized and two loading scenarios-no water and full reservoir operations-were investigated. At full
reservoir, the actual seepage line, as recorded over the years was used. The linear total stress
analysis using the finite element method of analysis was employed to analyze the dam section.
Following the finite element mathematical modeling and computer simulations of the models,
deformations and stresses distributions were determined. The results showed that the observed
longitudinal cracks at the Jebba main dam crest are as a result of potential cracks in the dam core
section. The cracks observed at the crest, from analysis, commenced from the dam’s core upstream
face, downstream face and core crest. This may have resulted from probable hydraulic fracturing
and tensile stresses developments in these regions. The results also showed likely loss of integrity of
core due to cracks. However, total collapse may not be experienced but dam performance may be
impaired and alarming visible cracks may not be ruled out over time.
Computer Aided Construction, Evaluation and Improvement of a Workplace Assembly Layout Using CADWORK
Authors: Udosen U.J.
Published: March 2009

A computerized approach as opposed to a manual approach provides a fast and easy
way of generating various workplace layouts in situ and consequently, CADWORK, a
computerized heuristic capable of constructing a workplace from scratch, evaluating and
improving a workplace fed into it, has been applied in this paper to design a workplace for the
assembly of a domestic fan. An assembly layout constructed and evaluated by CADWORK
yielded a cycle time of 1758.99 TMU at 100 BS performance level. Further modification of the
workplace to search for improvements yielded an assembly time of 1623.09 TMU for the
domestic fan.
Developing the Niger Delta Transport System Using Adequate Geo-Spatial Information
Authors: Ehiorobo J.O. , Audu Henry A.P.
Published: March 2009

The Niger Delta Region, although the back bone of Nigerian economy, has been
neglected by successive governments over time. There are no good schools, no health facilities, no
water and other facilities within this area. The problem of the area is compounded by lack of good
transportation system. This has been a hindrance both for security agencies and the people in the
restive area. A good transportation system should ensure that people, goods and services move
speedily, conveniently, safely and cost effectively. To have an efficient ground and water
transportation system needed in this area requires adequate and accurate Geo-spatial information. In
this paper, the benefits of adequate transportation system in the Niger Delta Region are highlighted.
The roles of Geo-spatial data and Geo-spatial information system in the planning, development and
management of an efficient transportation system are discussed. The paper also examines Geospatial
Data infrastructure (GDI) in the development of the Niger Delta transportation sector Master
plan, with data generated for Edo and Delta States presenting case study scenarios.
Intervention Analysis of Road Traffic Accidents in Nigeria
Authors: Igboanugo A.C. , Ekhuemelo E.Francis
Published: March 2009

This study reports on the development in road traffic accidents in Nigeria since 1994.
The preliminary survey took Edo state, one of the 36 constituent States of Nigeria, as a case study.
An intervention model, which is a combination of an ARIMA noise and dichotomous models, was
employed in analyzing a seven-year monthly accident time series obtained from the Federal Office
of Statistics and the Federal Road Safety Corps of Nigeria. The Durbin Watson’s test statistic, used
to ascertain the adequacy of our ARIMA predictive model, suggested that the intervention model
adopted has a good fit. The study points up a significant reduction in the rate of road traffic
accidents through multiple policy interventions of Nigeria.