Abstract: In this paper, a nonlinear acoustic echo cancellation
(AEC) system is proposed, whereby 3rd order Volterra filtering is
utilized along with a variable step-size Gauss-Seidel pseudo affine
projection (VSSGS-PAP) algorithm. In particular, the proposed
nonlinear AEC system is developed by considering a double-talk
situation with near-end signal variation. Simulation results
demonstrate that the proposed approach yields better nonlinear AEC
performance than conventional approaches.
Abstract: Due to urbanization, trees and plants which covered a great land mass of the earth and are an excellent carbon dioxide (CO2) absorber through photosynthesis are being replaced by several concrete based structures. It is therefore important to have these cement based structures absorb the large volume of carbon dioxide which the trees would have removed from the atmosphere during their useful lifespan. Hence the need for these cement based structures to be designed to serve other useful purposes in addition to shelter. This paper reviews the properties of Sodium carbonate and sugar as admixtures in concrete with respect to improving carbon sequestration in concrete.
Abstract: This paper presents a synthetic jet air blower actuated
by PZT for air blowing for air-breathing micro PEM fuel cell. The
several factors to affect the performance of air-breathing PEM fuel cell
such as air flow rate, opening ratio and cathode open type in the
cathode side were studied. Especially, an air flow rate is critical
condition to improve its performance. In this paper, we developed a
synthetic jet air blower to supply a high stoichiometric air flow. The
synthetic jet mechanism is a zero mass flux device that converts
electrical energy into the momentum. The synthetic jet actuation is
usually generated by a traditional PZT actuator, which consists of a
small cylindrical cavity, in/outlet channel and PZT diaphragms. The
flow rate of the fabricated synthetic jet air blower was 400cc/min at
550Hz and its power consumption was very low under 0.3W. The
proposed air-breathing PEM fuel cell which installed synthetic jet air
blower was higher performance and stability during continuous
operation than the air-breathing fuel cell without auxiliary device to
supply the air. The results showed that the maximum power density
was 188mW/cm2 at 400mA/cm2. This maximum power density and
durability were improved more than 40% and 20%, respectively.
Abstract: This paper presents the modeling and simulation of a hybrid proton exchange membrane fuel cell (PEMFC) with an energy storage system for use in a stand-alone distributed generation (DG) system. The simulation model consists of fuel cell DG, lead-acid battery, maximum power point tracking and power conditioning unit which is modeled in the MATLAB/Simulink platform. Poor loadfollowing characteristics and slow response to rapid load changes are some of the weaknesses of PEMFC because of the gas processing reaction and the fuel cell dynamics. To address the load-tracking issues in PEMFC, a hybrid PEMFC and battery storage system is considered and modelled. The model utilizes PEMFC as the main energy source whereas the battery functions as energy storage to compensate for the limitations of PEMFC.Simulation results are given to show the overall system performance under light and heavyloading conditions.
Abstract: A number of previous studies were rarely considered
the effects of transient non-uniform balloon expansion on evaluation
of the properties and behaviors of stents during stent expansion, nor
did they determine parameters to maximize the performances driven
by mechanical characteristics. Therefore, in order to fully understand
the mechanical characteristics and behaviors of stent, it is necessary to
consider a realistic modeling of transient non-uniform balloon-stent
expansion. The aim of the study is to propose design parameters
capable of improving the ability of vascular stent through a
comparative study of seven commercial stents using finite element
analyses of a realistic transient non-uniform balloon-stent expansion
process. In this study, seven representative commercialized stents were
evaluated by finite element (FE) analysis in terms of the criteria based
on the itemized list of Food and Drug Administration (FDA) and
European Standards (prEN). The results indicate that using stents
composed of opened unit cells connected by bend-shaped link
structures and controlling the geometrical and morphological features
of the unit cell strut or the link structure at the distal ends of stent may
improve mechanical characteristics of stent. This study provides a
better method at the realistic transient non-uniform balloon-stent
expansion by investigating the characteristics, behaviors, and
parameters capable of improving the ability of vascular stent.
Abstract: Although lighting systems powered by Photovoltaic
(PV) cells have existed for many years, they are not widely used,
especially in lighting for buildings, due to their high initial cost and
low conversion efficiency. One of the technical challenges facing PV
powered lighting systems has been how to use dc power generated by
the PV module to energize common light sources that are designed to
operate efficiently under ac power. Usually, the efficiency of the dc
light sources is very poor compared to ac light sources. Rapid
developments in LED lighting systems have made this technology a
potential candidate for PV powered lighting systems. This study
analyzed the efficiency of each component of PV powered lighting
systems to identify optimum system configurations for different
applications.
Abstract: In this paper, a simple microfluidic device for monitoring algal cell behavior is proposed. An array of algal microwells is fabricated by PDMS soft-lithography using X-ray LIGA mold, placed on a glass substrate. Two layers of replicated PDMS and substrate are attached by oxygen plasma bonding, creating a microchannel for the microfluidic system. Algal cell are loaded into the microfluidic device, which provides positive charge on the bottom surface of wells. Algal cells, which are negative charged, can be attracted to the bottom of the wells via electrostatic interaction. By varying the concentration of algal cells in the loading suspension, it is possible to obtain wells with a single cell. Liquid medium for cells monitoring are flown continuously over the wells, providing nutrient and waste exchange between the well and the main flow. This device could lead to the uncovering of the quantitative biology of the algae, which is a key to effective and extensive algal utilizations in the field of biotechnology, food industry and bioenergy research and developments.
Abstract: Embedding Sustainability in technological curricula has become a crucial factor for educating engineers with competences in sustainability. The Technical University of Catalonia UPC, in 2008, designed the Sustainable Technology Excellence Program STEP 2015 in order to assure a successful Sustainability Embedding. This Program takes advantage of the opportunity that the redesign of all Bachelor and Master Degrees in Spain by 2010 under the European Higher Education Area framework offered. The STEP program goals are: to design compulsory courses in each degree; to develop the conceptual base and identify reference models in sustainability for all specialties at UPC; to create an internal interdisciplinary network of faculty from all the schools; to initiate new transdisciplinary research activities in technology-sustainability-education; to spread the know/how attained; to achieve international scientific excellence in technology-sustainability-education and to graduate the first engineers/architects of the new EHEA bachelors with sustainability as a generic competence. Specifically, in this paper authors explain their experience in leading the STEP program, and two examples are presented: Industrial Robotics subject and the curriculum for the School of Architecture.
Abstract: The new architecture for quantum cellular
automata is offered. A QCA cell includes two layers nc-Si,
divided by a dielectric. Among themselves cells are connected
by the bridge from a conductive material. The comparison is
made between this and QCA, offered earlier by C. Lent's
group.
Abstract: Global approximation using metamodel for complex
mathematical function or computer model over a large variable
domain is often needed in sensibility analysis, computer simulation,
optimal control, and global design optimization of complex, multiphysics
systems. To overcome the limitations of the existing
response surface (RS), surrogate or metamodel modeling methods for
complex models over large variable domain, a new adaptive and
regressive RS modeling method using quadratic functions and local
area model improvement schemes is introduced. The method applies
an iterative and Latin hypercube sampling based RS update process,
divides the entire domain of design variables into multiple cells,
identifies rougher cells with large modeling error, and further divides
these cells along the roughest dimension direction. A small number
of additional sampling points from the original, expensive model are
added over the small and isolated rough cells to improve the RS
model locally until the model accuracy criteria are satisfied. The
method then combines local RS cells to regenerate the global RS
model with satisfactory accuracy. An effective RS cells sorting
algorithm is also introduced to improve the efficiency of model
evaluation. Benchmark tests are presented and use of the new
metamodeling method to replace complex hybrid electrical vehicle
powertrain performance model in vehicle design optimization and
optimal control are discussed.
Abstract: Toxoplasma gondii is an intracellular parasite capable
of infecting all nucleated cells in a diverse array of species.
Toxoplasma plaque assay have been described using Bacto Agar.
Because of its experimental advantages carboxymethyl cellulose
overlay, medium viscosity was choosing and the aim of this work
was to develop alternative method for formation of T. gondii plaques.
Tachyzoites were inoculated onto monolayers of Vero cells and
cultured at 37° C under 5 % CO2. The cultures were followed up by
microscopy inspection. Small plaques were visible by naphtol blue
stain 4 days after infection. Larger plaques could be observed by day
10 of culture. The carboxymethyl cellulose is a cheap reagent and the
methodology is easier, faster than assays under agar overlay. This is
the first description of the carboxymethyl cellulose overlay use for
obtaining the formation of T. gondii plaques and may be useful in
consequent obtaining tachyzoites for detailed studies.
Abstract: Sudoku is a kind of logic puzzles. Each puzzle consists
of a board, which is a 9×9 cells, divided into nine 3×3 subblocks
and a set of numbers from 1 to 9. The aim of this puzzle is to
fill in every cell of the board with a number from 1 to 9 such
that in every row, every column, and every subblock contains each
number exactly one. Sudoku puzzles belong to combinatorial problem
(NP complete). Sudoku puzzles can be solved by using a variety of
techniques/algorithms such as genetic algorithms, heuristics, integer
programming, and so on. In this paper, we propose a new approach for
solving Sudoku which is by modelling them as block-world problems.
In block-world problems, there are a number of boxes on the table
with a particular order or arrangement. The objective of this problem
is to change this arrangement into the targeted arrangement with the
help of two types of robots. In this paper, we present three models
for Sudoku. We modellized Sudoku as parameterized multi-agent
systems. A parameterized multi-agent system is a multi-agent system
which consists of several uniform/similar agents and the number of
the agents in the system is stated as the parameter of this system. We
use Temporal Logic of Actions (TLA) for formalizing our models.
Abstract: Antimicrobial (AM) starch-based films were
developed by incorporating chitosan and lauric acid as antimicrobial
agent into starch-based film. Chitosan has wide range of applications
as a biomaterial, but barriers still exist to its broader use due to its
physical and chemical limitations. In this work, a series of
starch/chitosan (SC) blend films containing 8% of lauric acid was
prepared by casting method. The structure of the film was
characterized by Fourier transform infrared spectroscopy (FTIR), Xray
diffraction (XRD), and scanning electron microscopy (SEM).
The results indicated that there were strong interactions were present
between the hydroxyl groups of starch and the amino groups of
chitosan resulting in a good miscibility between starch and chitosan
in the blend films. Physical properties and optical properties of the
AM starch-based film were evaluated. The AM starch-based films
incorporated with chitosan and lauric acid showed an improvement in
water vapour transmission rate (WVTR) and addition of starch
content provided more transparent films while the yellowness of the
film attributed to the higher chitosan content. The improvement in
water barrier properties was mainly attributed to the hydrophobicity
of lauric acid and optimum chitosan or starch content. AM starch
based film also showed excellent oxygen barrier. Obtaining films
with good oxygen permeability would be an indication of the
potential use of these antimicrobial packaging as a natural packaging
and an alternative packaging to the synthetic polymer to protect food
from oxidation reactions
Abstract: In this paper the FPGA implementations for four
stream ciphers are presented. The two stream ciphers, MUGI and
SNOW 2.0 are recently adopted by the International Organization for
Standardization ISO/IEC 18033-4:2005 standard. The other two
stream ciphers, MICKEY 128 and TRIVIUM have been submitted
and are under consideration for the eSTREAM, the ECRYPT
(European Network of Excellence for Cryptology) Stream Cipher
project. All ciphers were coded using VHDL language. For the
hardware implementation, an FPGA device was used. The proposed
implementations achieve throughputs range from 166 Mbps for
MICKEY 128 to 6080 Mbps for MUGI.
Abstract: In this paper, novel statistical sampling based equalization techniques and CNN based detection are proposed to increase the spectral efficiency of multiuser communication systems over fading channels. Multiuser communication combined with selective fading can result in interferences which severely deteriorate the quality of service in wireless data transmission (e.g. CDMA in mobile communication). The paper introduces new equalization methods to combat interferences by minimizing the Bit Error Rate (BER) as a function of the equalizer coefficients. This provides higher performance than the traditional Minimum Mean Square Error equalization. Since the calculation of BER as a function of the equalizer coefficients is of exponential complexity, statistical sampling methods are proposed to approximate the gradient which yields fast equalization and superior performance to the traditional algorithms. Efficient estimation of the gradient is achieved by using stratified sampling and the Li-Silvester bounds. A simple mechanism is derived to identify the dominant samples in real-time, for the sake of efficient estimation. The equalizer weights are adapted recursively by minimizing the estimated BER. The near-optimal performance of the new algorithms is also demonstrated by extensive simulations. The paper has also developed a (Cellular Neural Network) CNN based approach to detection. In this case fast quadratic optimization has been carried out by t, whereas the task of equalizer is to ensure the required template structure (sparseness) for the CNN. The performance of the method has also been analyzed by simulations.
Abstract: The treatment of the industrial wastewater can be
particularly difficult in the presence of toxic compounds. Excessive
concentration of Chromium in soluble form is toxic to a wide variety
of living organisms. Biological removal of heavy metals using natural
and genetically engineered microorganisms has aroused great interest
because of its lower impact on the environment. Ralston
metallidurans, formerly known as Alcaligenes eutrophus is a LProteobacterium
colonizing industrial wastewater with a high content
of heavy metals. Tris-buffered mineral salt medium was used for
growing Alcaligenes eutrophus AE104 (pEBZ141). The cells were
cultivated for 18 h at 30 oC in Tris-buffered mineral salt medium
containing 3 mM disodium sulphate and 46 mM sodium gluconate as
the carbon source. The cells were harvested by centrifugation,
washed, and suspended in 10 mM Tris HCl, pH 7.0, containing 46
mM sodium gluconate, and 5 mM Chromium. Interaction among
induction of chr resistance determinant, and chromate reduction have
been demonstrated. Results of this study show that the above bacteria
can be very useful for bioremediation of chromium from industrial
wastewater.
Abstract: A numerical study is made of laminar, unsteady flow
behind a rotationally oscillating circular cylinder using a recently
developed higher order compact (HOC) scheme. The stream function
vorticity formulation of Navier-Stokes (N-S) equations in cylindrical
polar coordinates are considered as the governing equations. The
temporal behaviour of vortex formation and relevant streamline
patterns of the flow are scrutinized over broad ranges of two
externally specified parameters namely dimensionless forced
oscillating frequency Sf and dimensionless peak rotation rate αm for
the Reynolds-s number Re = 200. Excellent agreements are found
both qualitatively and quantitatively with the existing experimental
and standard numerical results.
Abstract: The purposes of this paper are to (1) promote
excellence in computer science by suggesting a cohesive innovative
approach to fill well documented deficiencies in current computer
science education, (2) justify (using the authors- and others anecdotal
evidence from both the classroom and the real world) why this
approach holds great potential to successfully eliminate the
deficiencies, (3) invite other professionals to join the authors in proof
of concept research. The authors- experiences, though anecdotal,
strongly suggest that a new approach involving visual modeling
technologies should allow computer science programs to retain a
greater percentage of prospective and declared majors as students
become more engaged learners, more successful problem-solvers,
and better prepared as programmers. In addition, the graduates of
such computer science programs will make greater contributions to
the profession as skilled problem-solvers. Instead of wearily
rememorizing code as they move to the next course, students will
have the problem-solving skills to think and work in more
sophisticated and creative ways.
Abstract: The daily increase of organic waste materials resulting
from different activities in the country is one of the main factors for
the pollution of environment. Today, with regard to the low level of
the output of using traditional methods, the high cost of disposal
waste materials and environmental pollutions, the use of modern
methods such as anaerobic digestion for the production of biogas has
been prevailing. The collected biogas from the process of anaerobic
digestion, as a renewable energy source similar to natural gas but
with a less methane and heating value is usable. Today, with the help
of technologies of filtration and proper preparation, access to biogas
with features fully similar to natural gas has become possible. At
present biogas is one of the main sources of supplying electrical and
thermal energy and also an appropriate option to be used in four
stroke engine, diesel engine, sterling engine, gas turbine, gas micro
turbine and fuel cell to produce electricity. The use of biogas for
different reasons which returns to socio-economic and environmental
advantages has been noticed in CHP for the production of energy in
the world. The production of biogas from the technology of anaerobic
digestion and its application in CHP power plants in Iran can not only
supply part of the energy demands in the country, but it can
materialize moving in line with the sustainable development. In this
article, the necessity of the development of CHP plants with biogas
fuels in the country will be dealt based on studies performed from the
economic, environmental and social aspects. Also to prove the
importance of the establishment of these kinds of power plants from
the economic point of view, necessary calculations has been done as
a case study for a CHP power plant with a biogas fuel.
Abstract: Locating the critical slip surface with the minimum factor of safety for a rock slope is a difficult problem. In recent years, some modern global optimization methods have been developed with success in treating various types of problems, but very few of such methods have been applied to rock mechanical problems. In this paper, use of hybrid model based on artificial immune system and cellular learning automata is proposed. The results show that the algorithm is an effective and efficient optimization method with a high level of confidence rate.