Abstract: Silica fume, also known as microsilica (MS) or
condensed silica fume is a by-product of the production of silicon
metal or ferrosilicon alloys. Silica fume is one of the most effective
pozzolanic additives which could be used for ultrahigh performance
and other types of concrete. Despite the fact, however is not entirely
clear, which amount of silica fume is most optimal for UHPC. Main
objective of this experiment was to find optimal amount of silica
fume for UHPC with and without thermal treatment, when different
amount of quartz powder is substituted by silica fume. In this work
were investigated four different composition of UHPC with different
amount of silica fume. Silica fume were added 0, 10, 15 and 20% of
cement (by weight) to UHPC mixture. Optimal amount of silica fume
was determined by slump, viscosity, qualitative and quantitative
XRD analysis and compression strength tests methods.
Abstract: Buzan mind mapping is an efficient system of note-taking that makes revision a fun thing to do for students. Tony Buzan has been teaching children all over the world for the past thirty years and has proved that mind maps are the magic formula in the classroom for everyone. The purpose of this paper is to discuss the importance of Buzan mind mapping as a note-taking technique for the secondary school students. This paper also examines the mind mapping technique, advantages and disadvantages of hand-drawn mind maps. Samples of students’ mind maps were presented and discussed.
Abstract: A design problem of non-uniform circular antenna arrays for maximum reduction of both the side lobe level (SLL) and first null beam width (FNBW) is dealt with. This problem is modeled as a simple optimization problem. The method of Firefly algorithm (FFA) is used to determine an optimal set of current excitation weights and antenna inter-element separations that provide radiation pattern with maximum SLL reduction and much improvement on FNBW as well. Circular array antenna laid on x-y plane is assumed. FFA is applied on circular arrays of 8-, 10-, and 12- elements. Various simulation results are presented and hence performances of side lobe and FNBW are analyzed. Experimental results show considerable reductions of both the SLL and FNBW with respect to those of the uniform case and some standard algorithms GA, PSO and SA applied to the same problem.
Abstract: This paper describes optimal thinning of an Elliptical
Cylindrical Array (ECA) of uniformly excited isotropic antennas
which can generate directive beam with minimum relative Side Lobe
Level (SLL). The Particle Swarm Optimization (PSO) method, which
represents a new approach for optimization problems in
electromagnetic, is used in the optimization process. The PSO is used
to determine the optimal set of ‘ON-OFF’ elements that provides a
radiation pattern with maximum SLL reduction. Optimization is done
without prefixing the value of First Null Beam Width (FNBW). The
variation of SLL with element spacing of thinned array is also
reported. Simulation results show that the number of array elements
can be reduced by more than 50% of the total number of elements in
the array with a simultaneous reduction in SLL to less than -27dB.
Abstract: Bone hydatidosis is an infection in worldwide distribution. Although there is no evidence in literature on Bone Hydatid disease in Libya, we tried to present the first Epidemiological study of this disease in Eastern Libya through retrospective study from 1995 to 2013. Our data were collected from 3 hospitals in Eastern Libya particularly the sheep-raising areas with total number of musculoskeletal infection cases of two thousand one hundred ninety four (2,194). There were five (5) five cases of bone infection, four (4) of it have been diagnosed after more than three (3) months. Our study is comparable to other international study but this type of bone infection need further studies for effective control strategies for all dogs to avoid serious complications that might happened from the delay in diagnosing this type of disease.
Abstract: In this research, copper borates are synthesized by the
reaction of copper sulfate pentahydrate (CuSO4.5H2O) and
tincalconite (Na2O4B7.10H2O). The experimental parameters are
selected as 80oC reaction temperature and 60 of reaction time. The
effect of mole ratio of CuSO4.5H2O to Na2O4B7.5H2O is studied. For
the identification analyses X-Ray Diffraction (XRD) and Fourier
Transform Infrared Spectroscopy (FT-IR) techniques are used. At the
end of the experiments, synthesized copper borate is matched with
the powder diffraction file of “00-001-0472” [Cu(BO2)2] and
characteristic vibrations between B and O atoms are seen. The proper
crystals are obtained at the mole ratio of 3:1. This study showed that
simplified synthesis process is suitable for the production of copper
borate minerals.
Abstract: Compatibility between sulfonated acetone- formalehyde superplasticizer (SAF) and copolymer-based grinding aids (GA) were studied by fluidity, Zeta potential, setting time of cement pasts, initial slump and slump flow of concrete and compressive strength of concrete. ESEM, MIP, and XRD were used to investigate the changing of microstructure of interior concrete. The results indicated that GA could noticeably enhance the dispersion ability of SAF. It was found that better fluidity and slump-keeping ability of cement paste were obtained in the case of GA. In addition, GA together with SAF had a certain retardation effect on hydration of cement paste. With increasing of the GA dosage, the dispersion ability and retardation effect of admixture increased. The compressive strength of the sample made with SAF and GA after 28 days was higher than that of the control sample made only with SAF. The initial slump and slump flow of concrete increased by 10.0% and 22.9%, respectively, while 0.09 wt.% GA was used. XRD examination indicated that new products were not found in the case of GA. In addition, more dense arrangement of hydrates and lower porosity of the specimen were observed by ESEM and MIP, which contributed to higher compressive strength.
Abstract: Cubic equations of state like Redlich–Kwong (RK)
EOS have been proved to be very reliable tools in the prediction of
phase behavior. Despite their good performance in compositional
calculations, they usually suffer from weaknesses in the predictions
of saturated liquid density. In this research, RK equation was
modified. The result of this study show that modified equation has
good agreement with experimental data.
Abstract: Service quality is the highest requirement by users,
especially for the service in electronic government. During the past
decades, it has become a major area of academic investigation.
Considering this issue, there are a lot of researches that evaluated the
dimensions and e-service contexts. This study also identified the
dimensions of service quality, but focuses on a new concept and
provides a new methodology in developing measurement scales of
e-service quality such as information quality, service quality and
organization quality. Finally, this study will suggest a key factor to
evaluate e-government service quality better.
Abstract: Bone Anchored Hearing Implants (BAHI) are
routinely used in patients with conductive or mixed hearing loss, e.g.
if conventional air conduction hearing aids cannot be used. New
sound processors and new fitting software now allow the adjustment
of parameters such as loudness compression ratios or maximum
power output separately. Today it is unclear, how the choice of these
parameters influences aided speech understanding in BAHI users.
In this prospective experimental study, the effect of varying the
compression ratio and lowering the maximum power output in a
BAHI were investigated.
Twelve experienced adult subjects with a mixed hearing loss
participated in this study. Four different compression ratios (1.0; 1.3;
1.6; 2.0) were tested along with two different maximum power output
settings, resulting in a total of eight different programs. Each
participant tested each program during two weeks. A blinded Latin
square design was used to minimize bias.
For each of the eight programs, speech understanding in quiet and
in noise was assessed. For speech in quiet, the Freiburg number test
and the Freiburg monosyllabic word test at 50, 65, and 80 dB SPL
were used. For speech in noise, the Oldenburg sentence test was
administered.
Speech understanding in quiet and in noise was improved
significantly in the aided condition in any program, when compared
to the unaided condition. However, no significant differences were
found between any of the eight programs. In contrast, on a subjective
level there was a significant preference for medium compression
ratios of 1.3 to 1.6 and higher maximum power output.
Abstract: Grinding requires high specific energy and the consequent development of high temperature at tool-workpiece contact zone impairs workpiece quality by inducing thermal damage to the surface. Finishing grinding process requires component to be cut more than one pass. This paper deals with an investigation on the effect of multipass cutting on grinding performance in term of surface roughness and surface defect. An experimental set-up has been developed for this and a detailed comparison has been done with a single pass and various numbers of cutting pass. Results showed that surface roughness increase with the increase in a number of cutting pass. Good surface finish of 0.26μm was obtained for single pass cutting and 0.73μm for twenty pass cutting. It was also observed that the thickness of the white layer increased with the increased in a number of cutting pass.
Abstract: An experimental investigation has been carried out to study the cooling of a hot horizontal Stainless Steel surface of 3 mm thickness, which has 800±10 C initial temperature. A round water jet of 22 ± 1 oC temperature was injected over the hot surface through straight tube type nozzles of 2.5- 4.8 mm diameter and 250 mm length. The experiments were performed for the jet exit to target surface spacing of 4 times of jet diameter and jet Reynolds number of 5000 -24000. The effect of change in jet Reynolds number on the surface quenching has been investigated form the stagnation point to 16 mm spatial location.
Abstract: This paper introduces an open-source software package SCILAB [1], an alternative of MATLAB [2], which can be used for robust control design and analysis of a typical mass-spring-damper (MSD) system. Using the previously published ideas in [3,4], this popular mechanical system is considered to provide another example of usefulness of SCILAB for advanced control design.
Abstract: Progressive collapse of buildings typically occurs
when abnormal loading conditions cause local damages, which leads
to a chain reaction of failure and ultimately catastrophic collapse. The
tie force (TF) method is one of the main design approaches for
progressive collapse. As the TF method is a simplified method, further
investigations on the reliability of the method is necessary. This study
aims to develop an improved TF method to design the cross wall
structures for progressive collapse. To this end, the pullout behavior of
strands in grout was firstly analyzed; and then, by considering the tie
force-slip relationship in the friction stage together with the catenary
action mechanism, a comprehensive analytical method was developed.
The reliability of this approach is verified by the experimental results
of concrete block pullout tests and full scale floor-to-floor joints tests
undertaken by Portland Cement Association (PCA). Discrepancies in
the tie force between the analytical results and codified specifications
have suggested the deficiency of TF method, hence an improved
model based on the analytical results has been proposed to address this
concern.
Abstract: New developed approach for Functional Cost Analysis (FCA) based on virtual prototyping (VP) models in CAD/CAE environment, applicable and necessary in developing new products is presented. It is instrument for improving the value of the product while maintaining costs and/or reducing the costs of the product without reducing value. Five broad classes of VP methods are identified. Efficient use of prototypes in FCA is a vital activity that can make the difference between successful and unsuccessful entry of new products into the competitive word market. Successful realization of this approach is illustrated for a specific example using press joint power tool.
Abstract: The objective in this work is to generate and discuss the stability results of fully-immersed end-milling process with parameters; tool mass m=0.0431kg,tool natural frequency ωn = 5700 rads^-1, damping factor ξ=0.002 and workpiece cutting coefficient C=3.5x10^7 Nm^-7/4. Different no of teeth is considered for the end-milling. Both 1-DOF and 2-DOF chatter models of the system are generated on the basis of non-linear force law. Chatter stability analysis is carried out using a modified form (generalized for both 1-DOF and 2-DOF models) of recently developed method called Full-discretization. The full-immersion three tooth end-milling together with higher toothed end-milling processes has secondary Hopf bifurcation lobes (SHBL’s) that exhibit one turning (minimum) point each. Each of such SHBL is demarcated by its minimum point into two portions; (i) the Lower Spindle Speed Portion (LSSP) in which bifurcations occur in the right half portion of the unit circle centred at the origin of the complex plane and (ii) the Higher Spindle Speed Portion (HSSP) in which bifurcations occur in the left half portion of the unit circle. Comments are made regarding why bifurcation lobes should generally get bigger and more visible with increase in spindle speed and why flip bifurcation lobes (FBL’s) could be invisible in the low-speed stability chart but visible in the high-speed stability chart of the fully-immersed three-tooth miller.
Abstract: The author proposes an extension of genetic algorithm (GA) for solving fuzzy-valued optimization problems. In the proposed GA, values in the genotypes are not real numbers but fuzzy numbers. Evolutionary processes in GA are extended so that GA can handle genotype instances with fuzzy numbers. The proposed method is applied to evolving neural networks with fuzzy weights and biases. Experimental results showed that fuzzy neural networks evolved by the fuzzy GA could model hidden target fuzzy functions well despite the fact that no training data was explicitly provided.
Abstract: In neural networks, when new patters are learned by a network, they radically interfere with previously stored patterns. This
drawback is called catastrophic forgetting. We have already proposed a biologically inspired dual-network memory model which can much reduce this forgetting for static patterns. In this model, information is first stored in the hippocampal network, and thereafter, it is transferred to the neocortical network using pseudopatterns. Because temporal sequence learning is more important than static pattern learning in the real world, in this study, we improve our conventional dual-network memory model so that it can deal with temporal sequences without catastrophic forgetting. The computer simulation results show the effectiveness of the proposed dual-network memory model.
Abstract: Online shopping enables consumers to search for information and purchase products or services through direct interaction with online store. This study aims to examine the effect of Internet marketing environment, product characteristics, familiarity and confidence, and promotional offers on consumer online shopping behavior. 200 questionnaires were distributed to the respondents, who are students and staff at a public university in the Federal Territory of Labuan, Malaysia, following simple random sampling as a means of data collection. Multiple regression analysis was used as a statistical measure to determine the strength of the relationship between one dependent variable and a series of other independent variables. Results revealed that familiarity and confidence was found to greatly influence consumer online shopping behavior followed by promotional offers. A clear understanding of consumer online shopping behavior can help marketing managers predict the online shopping rate and evaluate the future growth of online commerce.
Abstract: Superfine pigments that consist of natural and artificial pigments and are made of mineral soil with special characteristics are used in cementitious materials for various purposes. These pigments can decrease the amount of cement needed without loss of performance and strength and also change the monotonous and turbid colours of concrete into various attractive and light colours. In this study, the mechanical strength and resistance against chloride and halogen attacks of cement mortars containing ceramic nano-pigments in an affected environment are studied. This research suggests utilisation of ceramic nano-pigments between 50 and 1000 nm, obtaining full-depth coloured concrete, preventing chlorine penetration in the concrete up to a certain depth, and controlling corrosion in steel rebar with the Potentiostat (EG&G) apparatus.