Abstract: The web services applications for digital reference
service (WSDRS) of LIS model is an informal model that claims to
reduce the problems of digital reference services in libraries. It uses
web services technology to provide efficient way of satisfying users’
needs in the reference section of libraries. The formal WSDRS model
consists of the Z specifications of all the informal specifications of
the model. This paper discusses the formal validation of the Z
specifications of WSDRS model. The authors formally verify and
thus validate the properties of the model using Z/EVES theorem
prover.
Abstract: The application of cold Radio-Frequency (RF) plasma
in the conservation of cultural heritage became important in the last
decades due to the positive results obtained in decontamination
treatments. This paper presents an equipment especially designed for cold RF
plasma application on paper documents, developed within a research
project. The equipment consists in two modules: the first one is
designed for decontamination and cleaning treatments of any type of
paper supports, while the second one can be used for coating friable
papers with adequate polymers, for protection purposes. All these
operations are carried out in cold radio-frequency plasma, working in
gaseous nitrogen, at low pressure. In order to optimize the equipment parameters ancient paper
samples infested with microorganisms have been treated in nitrogen
plasma and the decontamination effects, as well as changes in surface
properties (color, pH) were assessed. The microbiological analysis
revealed complete decontamination at 6 minutes treatment duration;
only minor modifications of the surface pH were found and the
colorimetric analysis showed a slight yellowing of the support.
Abstract: This study intends to show the influence of the
hydrolytic degradation on the properties of the e-PTFE/NOMEX®
membranes used in fire-protective clothing. The modification of
water vapour permeability, morphology and chemical structure was
examined by MOCON Permatran, electron microscopy scanning
(SEM), and ATR-FTIR, respectively. A decrease in permeability to
water vapour of the aged samples was observed following closure of
transpiration pores. Analysis of fiber morphology indicates the
appearance of defects at the fibers surface with the presence of micro
cavities. ATR-FTIR analysis reveals the presence of a new absorption
band attributed to carboxylic acid terminal groups generated during
the amide bond hydrolysis.
Abstract: Fiber Reinforced Polymer (FRP) is a composite material with exceptional properties that are capable to replace conventional steel reinforcement in reinforced and pre-stressed concrete structures. However, the main obstacle for their wide use in pre-stressed concrete application is the anchorage system. Due to the weakness of FRP in the transverse direction, the pre-stressing capacity of FRP bars are limited. This paper investigates the modification of the conventional wedge anchorage system to be used for stressing of FRP bars in pre-stressed applications. Epoxy adhesive material with glass FRP (GFRP) bars and conventional steel wedge were used in this paper. The GFRP bars are encased with epoxy at the anchor zone and the wedge system was used in pull-out test. The results showed a loading capacity of 47.6 kN which is 69% of the bar ultimate capacity. Additionally, nylon wedge was made with the same dimensions of the steel wedge and tested for GFRP bars without epoxy layer. The nylon wedge showed a loading capacity of 19.7 kN which is only 28.5% of the ultimate bar capacity.
Abstract: The properties of hollow sandcrete blocks produced in
Minna, Nigeria are presented. Sandcrete block is made of cement,
water and sand binded together in certain mix proportions. For the
purpose of this work, fifty (50) commercial sandcrete block industries
were visited in Minna, Nigeria to obtain block samples and
aggregates used for the manufacture, and to take inventory of the mix
composition and the production process. Sieve analysis tests were
conduction on the soil sample from various block industries to
ascertain their quality to be used for block making. The mix ratios
were also investigated. Five (5) nine inches (9’’ or 225mm) blocks
were obtained from each block industry and tested for dimensional
compliance and compressive strength. The results of the soil test
shows that the grading fall within the limit for natural aggregate and
can easily are used to obtain workable mix. Physical examinations of
the block sizes show slight deviation from the standard requirement
in NIS 87:2000. Compressive strength of hollow sandcrete blocks in
range of 0.12 N/mm2 to 0.54 N/mm2 was obtained which is below the
recommendable value of 3.45 N/mm2 for load bearing hollow
sandcrete blocks. This indicates that these blocks are below the
standard for load-bearing sandcrete blocks and cannot be used as load
bearing walling units. The mix composition also indicated low
cement content resulting in low compressive strength. Most of the
commercial block industries visited does not take curing very serious.
Water were only sprinkled ones or twice before the blocks were
stacked and made readily available for sale. It is recommended that a
mix ratio of 1:4 to 1:6 should be used for the production of sandcrete
blocks and proper curing practice should be adhered. Blocks should
also be cured for 14 days before making them available for
consumers.
Abstract: The fuel potential of six tropical hardwood species
namely: Triplochiton scleroxylon, Ceiba pentandra, Aningeria
robusta, Terminalia superba, Celtis mildbreadii and Piptadenia
africana were studied. Properties studied included species density,
gross calorific value, volatile matter, ash content, organic carbon and
elemental composition. Fuel properties were determined using
standard laboratory methods. The result indicates that the gross
calorific value (GCV) of the species ranged from 20.16 to 22.22
MJ/kg and they slightly varied from each other. Additionally, the
GCV of the biomass materials were higher than that of other biomass
materials like; wheat straw, rice straw, maize straw and sugar cane.
The ash and volatile matter content varied from 0.6075 to 5.0407%,
and 75.23% to 83.70% respectively. The overall rating of the
properties of the six biomass materials suggested that Piptadenia
africana has the best fuel property to be used as briquettes and
Aningeria robusta the worse. This study therefore suggests that a
holistic assessment of a biomass material needs to be done before
selecting it for fuel purpose.
Abstract: In this paper, the notion of rank−k numerical range
of rectangular complex matrix polynomials are introduced. Some
algebraic and geometrical properties are investigated. Moreover, for
Є > 0, the notion of Birkhoff-James approximate orthogonality
sets for Є−higher rank numerical ranges of rectangular matrix
polynomials is also introduced and studied. The proposed definitions
yield a natural generalization of the standard higher rank numerical
ranges.
Abstract: In this paper, relationship between different properties
of IC concrete and water cement ratio, obtained from a
comprehensive experiment conducted on IC using local materials
(Burnt clay chips- BC) is presented. In addition, saturated SAP was
used as an IC material in some cases. Relationships have been
developed through regression analysis. The focus of this analysis is
on developing relationship between a dependent variable and an
independent variable. Different percent replacements of BC and
water cement ratios were used. Compressive strength, modulus of
elasticity, water permeability and chloride permeability were tested
and variations of these parameters were analyzed with respect to
water cement ratio.
Abstract: The aim of the current work was to employ the finite
element method to model a slab, with a small hole across its width,
undergoing plastic plane strain deformation. The computational
model had, however, to be validated by comparing its results with
those obtained experimentally. Since they were in good agreement,
the finite element method can therefore be considered a reliable tool
that can help gain better understanding of the mechanism of ductile
failure in structural members having stress raisers. The finite element
software used was ANSYS, and the PLANE183 element was utilized.
It is a higher order 2-D, 8-node or 6-node element with quadratic
displacement behavior. A bilinear stress-strain relationship was used
to define the material properties, with constants similar to those of the
material used in the experimental study. The model was run for
several tensile loads in order to observe the progression of the plastic
deformation region, and the stress concentration factor was
determined in each case. The experimental study involved employing the visioplasticity
technique, where a circular mesh (each circle was 0.5 mm in
diameter, with 0.05 mm line thickness) was initially printed on the
side of an aluminum slab having a small hole across its width.
Tensile loading was then applied to produce a small increment of
plastic deformation. Circles in the plastic region became ellipses,
where the directions of the principal strains and stresses coincided
with the major and minor axes of the ellipses. Next, we were able to
determine the directions of the maximum and minimum shear
stresses at the center of each ellipse, and the slip-line field was then
constructed. We were then able to determine the stress at any point in
the plastic deformation zone, and hence the stress concentration
factor. The experimental results were found to be in good agreement
with the analytical ones.
Abstract: Concrete is strong in compression however weak in
tension. The tensile strength as well as ductile property of concrete
could be improved by addition of short dispersed fibers. Polyethylene
terephthalate (PET) fiber obtained from hand cutting or mechanical
slitting of plastic sheets generally used as discrete reinforcement in
substitution of steel fiber. PET fiber obtained from the former process
is in the form of straight slit sheet pattern that impart weaker
mechanical bonding behavior in the concrete matrix. To improve the
limitation of straight slit sheet fiber the present study considered two
additional geometry of fiber namely (a) flattened end slit sheet and
(b) deformed slit sheet. The mix for plain concrete was design for a
compressive strength of 25 MPa at 28 days curing time with a watercement
ratio of 0.5. Cylindrical and beam specimens with 0.5% fibers
volume fraction and without fibers were cast to investigate the
influence of geometry on the mechanical properties of concrete. The
performance parameters mainly studied include flexural strength,
splitting tensile strength, compressive strength and ultrasonic pulse
velocity (UPV). Test results show that geometry of fiber has a
marginal effect on the workability of concrete. However, it plays a
significant role in achieving a good compressive and tensile strength
of concrete. Further, significant improvement in term of flexural and
energy dissipation capacity were observed from other fibers as
compared to the straight slit sheet pattern. Also, the inclusion of PET
fiber improved the ability in absorbing energy in the post-cracking
state of the specimen as well as no significant porous structures.
Abstract: In recent years, the use of the aluminum based alloys
in the industry and technology are increasing. Alloying elements in
aluminum have further been improving the strength and stiffness
properties that provide superior compared to other metals. In this
study, investigation of physical properties (microstructure,
microhardness, tensile strength, electrical conductivity and thermal
properties) in the Al-12.6wt.%Si-%2wt.Ni ternary alloy were
investigated. Al-Si-Ni alloy was prepared in vacuum atmosphere. The
samples were directionally solidified upwards with different growth
rate V (8.3−165.45 μm/s) at constant temperature gradient G (7.73
K/mm). The flake spacings (λ), microhardness (HV), ultimate tensile
strength (σ), electrical resistivity (ρ) and thermal properties (H, Cp,
Tm) of the samples were measured. Influence of the growth rate and
spacings on microhardness, ultimate tensile strength and electrical
resistivity were investigated and relationships between them were
obtained. According to results, λ values decrease with increasing V,
but HV, σ and ρ values increase with increasing V. Variations of
electrical resistivity (ρ) of solidified samples were also measured.
The enthalpy of fusion (H) and specific heat (Cp) for the alloy was
also determined by differential scanning calorimeter (DSC) from
heating trace during the transformation from liquid to solid. The
results in this work were compared with the previous similar
experimental results.
Abstract: Consumers are demanding novel beverages that are
healthier, convenient and have appealing consumer acceptance. The
objectives of this study were to investigate the effects of adding grape
polyphenols and the influence of presenting health claims on the
sensory acceptability of wines. Fresh red sorrel calyces were
fermented into wines. The total soluble solids of the pectinase-treated
sorrel puree were from 4°Brix to 23.8°Brix. Polyphenol in the form
of grape pomace extract was added to sorrel wines (w/v) in specified
levels to give 0. 25. 50 and 75 ppm. A focus group comprising of 12
panelists was use to select the level of polyphenol to be added to
sorrel wines for sensory preference The sensory attributed of the
wines which were evaluated were colour, clarity, aroma, flavor,
mouth-feel, sweetness, astringency and overall preference. The sorrel
wine which was most preferred from focus group evaluation was
presented for hedonic rating. In the first stage of hedonic testing, the
sorrel wine was served chilled at 7°C for 24 h prior to sensory
evaluation. Each panelist was provided with a questionnaire and was
asked to rate the wines on colour, aroma, flavor, mouth-feel,
sweetness, astringency and overall acceptability using a 9-point
hedonic scale. In the second stage of hedonic testing, the panelist
were instructed to read a health abstract on the health benefits of
polyphenolic compounds and again to rate sorrel wine with added 25
ppm polyphenol. Paired t-test was used for the analysis of the
influence of presenting health information on polyphenols on hedonic
scoring of sorrel wines. Focus groups found that the addition of
polyphenol addition had no significant effect on sensory color and
aroma but affected clarity and flavor. A 25 ppm wine was liked
moderately in overall acceptability. The presentation of information
on the health benefit of polyphenols in sorrel wines to panelists had
no significant influence on the sensory acceptance of wine. More
than half of panelists would drink this wine now and then. This wine
had color L 19.86±0.68, chroma 2.10±0.12, hue° 16.90 ±3.10 and
alcohol content of 13.0%. The sorrel wine was liked moderately in
overall acceptability with the added polyphenols.
Abstract: The nickel-manganese (Ni-Mn) alloy coating prepared
from DC electrodeposition process in sulphamate bath was studied.
The effects of process parameters, such as current density and
electrolyte composition, on the cathodic current efficiency,
microstructure, internal stress and mechanical properties were
investigated. Because of its crucial effect on the application to the
electroforming of microelectronic components, the development of
low internal stress coating with high leveling power was emphasized.
It was found that both the coating’s manganese content and the
cathodic current efficiency increased with the raise in current density.
In addition, the internal stress of the deposited coating showed
compressive nature at low current densities while changed to tensile
one at higher current densities. Moreover, the metallographic
observation, X-ray diffraction measurement, and polarization curve
measurement were conducted. It was found that the Ni-Mn coating
consisted of nano-sized columnar grains and the maximum hardness of
the coating was associated with (111) preferred orientation in the
microstructure. The grain size was refined along with the increase in
the manganese content of the coating, which accordingly, raised its
hardness and resistance to annealing softening. In summary, the
Ni-Mn coating prepared at lower current density of 1-2 A/dm2 had low
internal stress, high leveling power, and better corrosion resistance.
Abstract: Sewer deposits have been identified as a major cause
of dysfunctions in combined sewer systems regarding sewer
management, which induces different negative consequents resulting
in poor hydraulic conveyance, environmental damages as well as
worker’s health. In order to overcome the problematics of
sedimentation, flushing has been considered as the most operative
and cost-effective way to minimize the sediments impacts and
prevent such challenges. Flushing, by prompting turbulent wave
effects, can modify the bed form depending on the hydraulic
properties and geometrical characteristics of the conduit. So far, the
dynamics of the bed-load during high-flow events in combined sewer
systems as a complex environment is not well understood, mostly due
to lack of measuring devices capable to work in the “hostile” in
combined sewer system correctly. In this regards, a one-episode
flushing issue from an opening gate valve with weir function was
carried out in a trunk sewer in Paris to understand its cleansing
efficiency on the sediments (thickness: 0-30 cm). During more than
1h of flushing within 5 m distance in downstream of this flushing
device, a maximum flowrate and a maximum level of water have
been recorded at 5 m in downstream of the gate as 4.1 m3/s and 2.1
m respectively. This paper is aimed to evaluate the efficiency of this
type of gate for around 1.1 km (from the point -50 m to +1050 m in
downstream from the gate) by (i) determining bed grain-size
distribution and sediments evolution through the sewer channel, as
well as their organic matter content, and (ii) identifying sections that
exhibit more changes in their texture after the flush. For the first one,
two series of sampling were taken from the sewer length and then
analyzed in laboratory, one before flushing and second after, at same
points among the sewer channel. Hence, a non-intrusive sampling
instrument has undertaken to extract the sediments smaller than the
fine gravels. The comparison between sediments texture after the
flush operation and the initial state, revealed the most modified zones
by the flush effect, regarding the sewer invert slope and hydraulic
parameters in the zone up to 400 m from the gate. At this distance,
despite the increase of sediment grain-size rages, D50 (median grainsize)
varies between 0.6 mm and 1.1 mm compared to 0.8 mm and 10
mm before and after flushing, respectively. Overall, regarding the
sewer channel invert slope, results indicate that grains smaller than
sands (< 2 mm) are more transported to downstream along about 400
m from the gate: in average 69% before against 38% after the flush
with more dispersion of grain-sizes distributions. Furthermore, high
effect of the channel bed irregularities on the bed material evolution
has been observed after the flush.
Abstract: This study aims to investigate the mixing behaviors of
deionized (DI) water and carboxymethyl cellulose (CMC) solutions in
C-shaped serpentine micromixers over a wide range of flow
conditions. The flow of CMC solutions exhibits shear-thinning
behaviors. Numerical simulations are performed to investigate the
effects of the mean flow speed, fluid properties and geometry
parameters on flow and mixing in the micromixers with the serpentine
channel of the same overall channel length. From the results, we can
find the following trends. When convection dominates fluid mixing,
the curvature-induced vortices enhance fluid mixing effectively. The
mixing efficiency of a micromixer consisting of semicircular C-shaped
repeating units with a smaller centerline radius is better than that of a
micromixer consisting of major segment repeating units with a larger
centerline radius. The viscosity of DI water is less than the overall
average apparent viscosity of CMC solutions, and so the effect of
curvature-induced vortices on fluid mixing in DI water is larger than
that in CMC solutions for the cases with the same mean flow speed.
Abstract: Conductivity properties of DNA molecule is
investigated in a simple, but chemically specific approach that is
intimately related to the Su-Schrieffer-Heeger (SSH) model. This
model is a tight-binding linear nanoscale chain. We have tried to
study the electrical current flowing in DNA and investigated the
characteristic I-V diagram. As a result, It is shown that there are the
(quasi-) ohmic areas in I-V diagram. On the other hand, the regions
with a negative differential resistance (NDR) are detectable in
diagram.
Abstract: Work presented is interested in the characterization of
the quasistatic mechanical properties and in fatigue of a composite
laminated in jute/epoxy. The natural fibers offer promising prospects
thanks to their interesting specific properties, because of their low
density, but also with their bio-deterioration. Several scientific
studies highlighted the good mechanical resistance of the vegetable
fiber composites reinforced, even after several recycling. Because of
the environmental standards that become increasingly severe, one
attends the emergence of eco-materials at the base of natural fibers
such as flax, bamboo, hemp, sisal, jute. The fatigue tests on
elementary vegetable fibers show an increase of about 60% of the
rigidity of elementary fibers of hemp subjected to cyclic loadings. In
this study, the test-tubes manufactured by the method infusion have
sequences of stacking of 0/90° and ± 45° for the shearing and tensile
tests. The quasistatic tests reveal a variability of the mechanical
properties of about 8%. The tensile fatigue tests were carried out for
levels of constraints equivalent to half of the ultimate values of the
composite. Once the fatigue tests carried out for well-defined values
of cycles, a series of static tests of traction type highlights the
influence of the number of cycles on the quasi-static mechanical
behavior of the laminate jute/epoxy.
Abstract: Steel slag is a by-product of the steel industry and can
be used potentially as aggregate in the asphalt mixture. This study
evaluates the use of Steel Slag Aggregates (SSA) as a substitute for
natural aggregates in the production of hot mix asphalt (HMA) for
road construction. Based on intensive laboratory testing program, the
characteristic properties of SSA were assessed to determine its
suitability to be used in HMA. Four different percentages (0, 50, 75,
and 100%) of SSA were used, and the proposed mix designs for
HMA were conducted in accordance with Marshall mix design. The
experiment results revealed that the addition of SSA has a significant
improvement on the properties of HMA. An increase in density and
stability and a reduction in flow and air voids values were clearly
observed in specimens prepared with 100% SSA. It is concluded that
the steel slag can be considered reasonable alternative source of
aggregate for concrete asphalt mixture production.
Abstract: High frequency automotive interior noise above 500
Hz considerably affects automotive passenger comfort. To reduce this
noise, sound insulation material is often laminated on body panels or
interior trim panels. For a more effective noise reduction, the sound
reduction properties of this laminated structure need to be estimated.
We have developed a new calculate tool that can roughly calculate the
sound absorption and insulation properties of laminate structure and
handy for designers. In this report, the outline of this tool and an
analysis example applied to floor mat are introduced.
Abstract: Standard Gibbs energy of formation ΔGfor(298.15) of
lanthanide-iron double oxides of garnet-type crystal structure
R3Fe5O12 - RIG (R – are rare earth ions) from initial oxides are
evaluated. The calculation is based on the data of standard entropies
S298.15 and standard enthalpies ΔH298.15 of formation of compounds
which are involved in the process of garnets synthesis. Gibbs energy
of formation is presented as temperature function ΔGfor(T) for the
range 300-1600K. The necessary starting thermodynamic data were
obtained from calorimetric study of heat capacity – temperature
functions and by using the semi-empirical method for calculation of
ΔH298.15 of formation. Thermodynamic functions for standard
temperature – enthalpy, entropy and Gibbs energy - are
recommended as reference data for technological evaluations.
Through the structural series of rare earth-iron garnets the correlation
between thermodynamic properties and characteristics of lanthanide
ions are elucidated.