Abstract: A new SUZ-4 zeolite membrane with
tetraethlyammonium hydroxide as the template was fabricated on
mullite tube via hydrothermal sol-gel synthesis in a rotating
autoclave reactor. The suitable synthesis condition was SiO2:Al2O3
ratio of 21.2 for 4 days at 155 °C crystallization under autogenous
pressure. The obtained SUZ-4 possessed a high BET surface area of
396.4 m2/g, total pore volume at 2.611 cm3/g, and narrow pore size
distribution with 97 nm mean diameter and 760 nm long of needle
crystal shape. The SUZ-4 layer obtained from seeding crystallization
was thicker than that of without seeds or in situ crystallization.
Abstract: This is a study on numerical simulation of the convection-diffusion transport of a chemical species in steady flow through a small-diameter tube, which is lined with a very thin layer made up of retentive and absorptive materials. The species may be subject to a first-order kinetic reversible phase exchange with the wall material and irreversible absorption into the tube wall. Owing to the velocity shear across the tube section, the chemical species may spread out axially along the tube at a rate much larger than that given by the molecular diffusion; this process is known as dispersion. While the long-time dispersion behavior, well described by the Taylor model, has been extensively studied in the literature, the early development of the dispersion process is by contrast much less investigated. By early development, that means a span of time, after the release of the chemical into the flow, that is shorter than or comparable to the diffusion time scale across the tube section. To understand the early development of the dispersion, the governing equations along with the reactive boundary conditions are solved numerically using the Flux Corrected Transport Algorithm (FCTA). The computation has enabled us to investigate the combined effects on the early development of the dispersion coefficient due to the reversible and irreversible wall reactions. One of the results is shown that the dispersion coefficient may approach its steady-state limit in a short time under the following conditions: (i) a high value of Damkohler number (say Da ≥ 10); (ii) a small but non-zero value of absorption rate (say Γ* ≤ 0.5).
Abstract: Tanzania is a developing country, which significantly lags behind the rest of the world in information communications technology (ICT), especially for the Internet. Internet connectivity to the rest of the world is via expensive satellite links, thus leaving the majority of the population unable to access the Internet due to the high cost. This paper introduces the concept of an optical WDM network for Internet infrastructure in Tanzania, so as to reduce Internet connection costs, and provide Internet access to the majority of people who live in both urban and rural areas. We also present a proposed optical WDM network, which mitigates the effects of system impairments, and provide simulation results to show that the data is successfully transmitted over a longer distance using a WDM network.
Abstract: Automotive engine air-ratio plays an important role of
emissions and fuel consumption reduction while maintains
satisfactory engine power among all of the engine control variables. In
order to effectively control the air-ratio, this paper presents a model
predictive fuzzy control algorithm based on online least-squares
support vector machines prediction model and fuzzy logic optimizer.
The proposed control algorithm was also implemented on a real car for
testing and the results are highly satisfactory. Experimental results
show that the proposed control algorithm can regulate the engine
air-ratio to the stoichiometric value, 1.0, under external disturbance
with less than 5% tolerance.
Abstract: How to efficiently assign system resource to route the
Client demand by Gateway servers is a tricky predicament. In this
paper, we tender an enhanced proposal for autonomous recital of
Gateway servers under highly vibrant traffic loads. We devise a
methodology to calculate Queue Length and Waiting Time utilizing
Gateway Server information to reduce response time variance in
presence of bursty traffic.
The most widespread contemplation is performance, because
Gateway Servers must offer cost-effective and high-availability
services in the elongated period, thus they have to be scaled to meet
the expected load. Performance measurements can be the base for
performance modeling and prediction. With the help of performance
models, the performance metrics (like buffer estimation, waiting
time) can be determined at the development process.
This paper describes the possible queue models those can be
applied in the estimation of queue length to estimate the final value
of the memory size. Both simulation and experimental studies using
synthesized workloads and analysis of real-world Gateway Servers
demonstrate the effectiveness of the proposed system.
Abstract: Most file systems overwrite modified file data and
metadata in their original locations, while the Log-structured File
System (LFS) dynamically relocates them to other locations. We
design and implement the Evergreen file system that can select
between overwriting or relocation for each block of a file or metadata.
Therefore, the Evergreen file system can achieve superior write
performance by sequentializing write requests (similar to LFS-style
relocation) when space utilization is low and overwriting when
utilization is high. Another challenging issue is identifying
performance benefits of LFS-style relocation over overwriting on a
newly introduced SSD (Solid State Drive) which has only
Flash-memory chips and control circuits without mechanical parts.
Our experimental results measured on a SSD show that relocation
outperforms overwriting when space utilization is below 80% and vice
versa.
Abstract: Public parks are placed high on the research agenda, with many studies addressing their social, economic and environment influences in different countries around the world. They have been recognized as contributors to the physical quality of urban environments. Recently, a broader view of public parks has emerged. This view goes well beyond the traditional value of parks as places for more recreation and visual delight, to depict them as valuable contributors to broader strategic objectives, such as property values, place attractiveness, job opportunities, social belonging, public health, tourist development, and improving the overall quality of life. This research examines the role of public parks in enhancing the quality of human life in Egyptian environment. It measures 'quality of life' in terms of 'human needs' and 'well-being'. This should open ways for policymakers, practitioners, researchers and the public to realize the potentials of public parks towards improving the quality of life.
Abstract: The estimation of overall on-site and off-site greenhouse gas (GHG) emissions by wastewater treatment plants revealed that in anaerobic and hybrid treatment systems greater emissions result from off-site processes compared to on-site processes. However, in aerobic treatment systems, onsite processes make a higher contribution to the overall GHG emissions. The total GHG emissions were estimated to be 1.6, 3.3 and 3.8 kg CO2-e/kg BOD in the aerobic, anaerobic and hybrid treatment systems, respectively. In the aerobic treatment system without the recovery and use of the generated biogas, the off-site GHG emissions were 0.65 kg CO2-e/kg BOD, accounting for 40.2% of the overall GHG emissions. This value changed to 2.3 and 2.6 kg CO2-e/kg BOD, and accounted for 69.9% and 68.1% of the overall GHG emissions in the anaerobic and hybrid treatment systems, respectively. The increased off-site GHG emissions in the anaerobic and hybrid treatment systems are mainly due to material usage and energy demand in these systems. The anaerobic digester can contribute up to 100%, 55% and 60% of the overall energy needs of plants in the aerobic, anaerobic and hybrid treatment systems, respectively.
Abstract: Conventional materials like glass, wood or metals
replacement with polymer materials is still continuing. More simple
thus cheaper production is the main reason. However due to high
energy and petrochemical prices are polymer prices increasing too.
That´s why various kinds of fillers are used to make polymers
cheaper. Of course target is to maintain or improve properties of
these compounds. In this paper are solved rheology issues of
polymers compounded with vegetal origin fibers.
Abstract: In this study, oxidative steam reforming of methanol (OSRM) over a Au/CeO2–Fe2O3 catalyst prepared by a depositionprecipitation (DP) method was studied to produce hydrogen in order to feed a Proton Exchange Membrane Fuel Cell (PEMFC). The support (CeO2, Fe2O3, and CeO2–Fe2O3) were prepared by precipitation and co-precipitation methods. The impact of the support composition on the catalytic performance was studied by varying the Ce/(Ce+Fe) atomic ratio, it was found that the 1%Au/CF(0.25) calcined at 300 °C exhibited the highest catalytic activity in the whole temperature studied. In addition, the effect of Au content was investigated and 3%Au/CF(0.25) exhibited the highest activity under the optimum condition in the temperature range of 200 °C to 400 °C. The catalysts were characterized by various techniques: XRD, TPR, XRF, and UV-vis.
Abstract: The study investigates the relationship between
education level, workplace learning behaviors, psychological
empowerment and burnout in a sample of 191 teachers. We
hypothesized that education level will positively affect psychological
state of increased empowerment and decreased burnout, and we
purposed that these effects will be mediated by workplace learning
behaviors. We used multiple regression analyses to test the model
that included also the 6 following control variables: The teachers'
age, gender, and teaching tenure; the schools' religious level, the
pupils' needs: regular/ special needs, and the class level: elementary/
high school. The results support the purposed mediating model.
Abstract: Postmenopausal osteoporosis is a disorder
characterized by the progressive bone loss induced by estrogen
deficiency in postmenopausal women. This imbalance affects
calcium–phosphate metabolism and results in secondary
hyperparathyroidism. Purariae Radix (PR), the root of P. lobata
(Wild.) Ohwi, is one of the earliest medicinal herbs employed in
ancient China. PR contains a high quantity of isoflavones and their
glycosides, which are regarded as phytoestrogen. Few investigations
of PR are related to its osteoprotective effects. The present study is
designed to administer PR water extract to ovariectomized (OVX)
female rats, for the investigation of its possibly protective actions on
bone and to delineate the potential mechanisms involved. Our results
demonstrated that long-term treatment of PR could not significantly
improve bone properties, whereas it greatly ameliorated the condition
of secondary hyperparathyroidism induced by ovariectomy in those
animals. PR might be useful as alternative regimen for protecting
against postmenopausal bone loss.
Abstract: The great majority of the electric installations belong
to the first and second category. In order to ensure a high level of
reliability of their electric system feeder, two power supply sources
are envisaged, one principal, the other of reserve, generally a cold
reserve (electric diesel group).
The principal source being under operation, its control can be ideal
and sure, however for the reserve source being in stop, a preventive
maintenance-s which proceeds on time intervals (periodicity) and
for well defined lengths of time are envisaged, so that this source will
always available in case of the principal source failure.
The choice of the periodicity of preventive maintenance of the
source of reserve influences directly the reliability of the electric
feeder system. On the basis of the semi-markovians processes, the
influence of the periodicity of the preventive maintenance of the
source of reserve is studied and is given the optimal periodicity.
Abstract: Reactive powder concretes (RPC) are characterized by
particle diameter not exceeding 600 μm and having very high
compressive and tensile strengths. This paper describes a new
generation of micro concrete, which has an initial, as well as a final,
high physicomechanical performance. To achieve this, we replaced
the Portland cement (15% by weight) by materials rich in Silica (Slag
and Dune Sand).
The results obtained from tests carried out on RPC show that
compressive and tensile strengths increase when adding the additions,
thus improving the compactness of mixtures via filler and pozzolanic
effect.
With a reduction of the aggregate phase in the RPC and the
abundance of dune sand (south Algeria) and slag (industrial byproduct
of blast furnace), the use of the RPC will allow Algeria to
fulfil economical as well as ecological requirements.
Abstract: By taking advantage of both k-NN which is highly
accurate and K-means cluster which is able to reduce the time of classification, we can introduce Cluster-k-Nearest Neighbor as "variable k"-NN dealing with the centroid or mean point of all subclasses generated by clustering algorithm. In general the algorithm of K-means cluster is not stable, in term of accuracy, for that reason we develop another algorithm for clustering our space which gives a higher accuracy than K-means cluster, less
subclass number, stability and bounded time of classification with respect to the variable data size. We find between 96% and 99.7 % of accuracy in the lassification of 6 different types of Time series by using K-means cluster algorithm and we find 99.7% by using the new clustering algorithm.
Abstract: The exhaustive quality control is becoming more and
more important when commercializing competitive products in the
world's globalized market. Taken this affirmation as an undeniable
truth, it becomes critical in certain sector markets that need to offer
the highest restrictions in quality terms. One of these examples is the
percussion cap mass production, a critical element assembled in
firearm ammunition. These elements, built in great quantities at a
very high speed, must achieve a minimum tolerance deviation in
their fabrication, due to their vital importance in firing the piece of
ammunition where they are built in. This paper outlines a machine
vision development for the 100% inspection of percussion caps
obtaining data from 2D and 3D simultaneous images. The acquisition
speed and precision of these images from a metallic reflective piece
as a percussion cap, the accuracy of the measures taken from these
images and the multiple fabrication errors detected make the main
findings of this work.
Abstract: This paper presents a highly efficient algorithm for detecting and tracking humans and objects in video surveillance sequences. Mean shift clustering is applied on backgrounddifferenced image sequences. For efficiency, all calculations are performed on integral images. Novel corresponding exponential integral kernels are introduced to allow the application of nonuniform kernels for clustering, which dramatically increases robustness without giving up the efficiency of the integral data structures. Experimental results demonstrating the power of this approach are presented.
Abstract: Much has been written about the difficulties students
have with producing traditional dissertations. This includes both
native English speakers (L1) and students with English as a second
language (L2). The main emphasis of these papers has been on the
structure of the dissertation, but in all cases, even when electronic
versions are discussed, the dissertation is still in what most would
regard as a traditional written form.
Master of Science Degrees in computing disciplines require
students to gain technical proficiency and apply their knowledge to a
range of scenarios. The basis of this paper is that if a dissertation is a
means of showing that such a student has met the criteria for a pass,
which should be based on the learning outcomes of the dissertation
module, does meeting those outcomes require a student to
demonstrate their skills in a solely text based form, particularly in a
highly technical research project? Could it be possible for a student
to produce a series of related artifacts which form a cohesive package
that meets the learning out comes of the dissertation?
Abstract: Structural and UV/Visible optical properties can be
useful to describe a material for the CIGS solar cell active layer,
therefore, this work demonstrates the properties like surface
morphology, X-ray Photoelectron Spectroscopy (XPS) bonding
energy (EB) core level spectra, UV/Visible absorption spectra,
refractive index (n), optical energy band (Eg), reflection spectra for
the Cu25 (In16Ga9) Se40Te10 (CIGST-1) and Cu20 (In14Ga9) Se45Te12
(CIGST-2) chalcogenide compositions. Materials have been
exhibited homogenous surface morphologies, broading /-or diffusion
of bonding energy peaks relative elemental values and a high
UV/Visible absorption tendency in the wave length range 400 nm-
850 nm range with the optical energy band gaps 1.37 and 1.42
respectively. Subsequently, UV/Visible reflectivity property in the
wave length range 250 nm to 320 nm for these materials has also
been discussed.
Abstract: The urban centers within northeastern Brazil are
mainly influenced by the intense rainfalls, which can occur after long
periods of drought, when flood events can be observed during such
events. Thus, this paper aims to study the rainfall frequencies in such
region through the wavelet transform. An application of wavelet
analysis is done with long time series of the total monthly rainfall
amount at the capital cities of northeastern Brazil. The main
frequency components in the time series are studied by the global
wavelet spectrum and the modulation in separated periodicity bands
were done in order to extract additional information, e.g., the 8 and
16 months band was examined by an average of all scales, giving a
measure of the average annual variance versus time, where the
periods with low or high variance could be identified. The important
increases were identified in the average variance for some periods,
e.g. 1947 to 1952 at Teresina city, which can be considered as high
wet periods. Although, the precipitation in those sites showed similar
global wavelet spectra, the wavelet spectra revealed particular
features. This study can be considered an important tool for time
series analysis, which can help the studies concerning flood control,
mainly when they are applied together with rainfall-runoff
simulations.