Abstract: novel and simple method is introduced for rapid and
highly efficient water treatment by reverse osmosis (RO) method using
multi-walled carbon nanotubes (MWCNTs) / polyacrylonitrile (PAN)
polymer as a flexible, highly efficient, reusable and semi-permeable
mixed matrix membrane (MMM). For this purpose, MWCNTs were
directly synthesized and on-line purified by chemical vapor deposition
(CVD) process, followed by directing the MWCNT bundles towards an
ultrasonic bath, in which PAN polymer was simultaneously suspended
inside a solid porous silica support in water at temperature to ~70 οC.
Fabrication process of MMM was finally completed by hot isostatic
pressing (HIP) process. In accordance with the analytical figures of
merit, the efficiency of fabricated MMM was ~97%. The rate of water
treatment process was also evaluated to 6.35 L min-1. The results reveal
that, the CNT-based MMM is suitable for rapid treatment of different
forms of industrial, sea, drinking and well water samples.
Abstract: In this article, we propose a methodology for the
characterization of the suspended matter along Algiers-s bay. An
approach by multi layers perceptron (MLP) with training by back
propagation of the gradient optimized by the algorithm of Levenberg
Marquardt (LM) is used. The accent was put on the choice of the
components of the base of training where a comparative study made
for four methods: Random and three alternatives of classification by
K-Means. The samples are taken from suspended matter image,
obtained by analytical model based on polynomial regression by
taking account of in situ measurements. The mask which selects the
zone of interest (water in our case) was carried out by using a multi
spectral classification by ISODATA algorithm. To improve the
result of classification, a cleaning of this mask was carried out using
the tools of mathematical morphology. The results of this study
presented in the forms of curves, tables and of images show the
founded good of our methodology.
Abstract: The recommendation of the committee on corporate
governance for public companies in Nigeria, that the position of the
CEO be separated from board chair has generated serious debate
among scholars and practitioners. They have questioned the
appropriateness of implementing corporate governance model that is
based on Anglo-Saxon agency problem characterized by dispersed
ownership structure; where markets for corporate control, legal
regulation, and contractual incentives are the key governance
mechanisms. This paper strives to resolve the argument by adopting
an institutional perspective in testing the agency theory on board
duality. The study developed a theoretical and empirical model to
better understand how ownership structure influences agency conflict
and how such affects firm performance. Hence, the study examines
the relationship between CEO duality and firm performance using
two institutional ownership structures – dispersed ownership and
concentrated ownership structures. The empirical results show that
CEO duality is negatively correlated with firm performance in
Nigeria irrespective of the firm-s ownership structure. The findings
give credence to the recommendation of the Peterside Commission
on the need to separate the position of CEO from board chair.
Abstract: An experiment was conducted under controlled
conditions to study the effect of water extract of leaves, shoots and
roots of either Sisymbrium irio L. =SISIR and or Descurainia
sophia (L.) Schur =DESSO on the germination and primary growth
of barley. A split-split plot experiment in CRD with three
replications was used. The main plots were the type of weed: i.e.
SISIR and DESSO and the sub-plots were type of organ: i.e. leaf,
stem and root and, the sub-sub plots were concentration of the
water extract of each organ of the weeds: i.e. 0, 2, 4 and 8 % w/v.
The results showed that the SISIR water extracts had a greater
inhibitory effects on the germination and primary growth of barley
than those of DESSO water extracts. The water extracts of the
leaves of both weeds had the greatest inhibitory effects on the
germination and primary growth of barley, compared to those of
stems and roots. Increasing the concentration of water extracts of
leaves, stems and roots of both weeds up to 8 % caused the greatest
inhibitory effects to barley and reduced the germination rate and
primary growth of it linearly.
Abstract: Image registration plays an important role in the
diagnosis of dental pathologies such as dental caries, alveolar bone
loss and periapical lesions etc. This paper presents a new wavelet
based algorithm for registering noisy and poor contrast dental x-rays.
Proposed algorithm has two stages. First stage is a preprocessing
stage, removes the noise from the x-ray images. Gaussian filter has
been used. Second stage is a geometric transformation stage.
Proposed work uses two levels of affine transformation. Wavelet
coefficients are correlated instead of gray values. Algorithm has been
applied on number of pre and post RCT (Root canal treatment)
periapical radiographs. Root Mean Square Error (RMSE) and
Correlation coefficients (CC) are used for quantitative evaluation.
Proposed technique outperforms conventional Multiresolution
strategy based image registration technique and manual registration
technique.
Abstract: This paper presents a possibilistic (fuzzy) model in optimal siting and sizing of Distributed Generation (DG) for loss reduction and improve voltage profile in power distribution system. Multi-objective problem is developed in two phases. In the first one, the set of non-dominated planning solutions is obtained (with respect to the objective functions of fuzzy economic cost, and exposure) using genetic algorithm. In the second phase, one solution of the set of non-dominated solutions is selected as optimal solution, using a suitable max-min approach. This method can be determined operation-mode (PV or PQ) of DG. Because of considering load uncertainty in this paper, it can be obtained realistic results. The whole process of this method has been implemented in the MATLAB7 environment with technical and economic consideration for loss reduction and voltage profile improvement. Through numerical example the validity of the proposed method is verified.
Abstract: Combining classifiers is a useful method for solving
complex problems in machine learning. The ECOC (Error Correcting
Output Codes) method has been widely used for designing combining
classifiers with an emphasis on the diversity of classifiers. In this
paper, in contrast to the standard ECOC approach in which individual
classifiers are chosen homogeneously, classifiers are selected
according to the complexity of the corresponding binary problem. We
use SATIMAGE database (containing 6 classes) for our experiments.
The recognition error rate in our proposed method is %10.37 which
indicates a considerable improvement in comparison with the
conventional ECOC and stack generalization methods.
Abstract: Gaharu that produced by Aquilaria spp. is classified as
one of the most valuable forest products traded internationally as it is
very resinous, fragrant and highly valuable heartwood. Gaharu has
been widely used in aromatheraphy, medicine, perfume and religious
practices. This work aimed to determine the factors affecting solid
liquid extraction of gaharu oil using hexane as solvent under
experimental condition. The kinetics of extraction was assumed and
verified based on a second-order mechanism. The effect of three
main factors, which were temperature, reaction time and solvent to
solid ratio were investigated to achieve maximum oil yield. The
optimum condition were found at temperature 65°C, 9 hours reaction
time and solvent to solid ratio of 12:1 with 14.5% oil yield. The
kinetics experimental data agrees and well fitted with the second
order extraction model. The initial extraction rate (h) was 0.0115
gmL-1min-1; the extraction capacity (Cs) was 1.282gmL-1; the second
order extraction constant (k) was 0.007 mLg-1min-1 and coefficient of
determination, R2 was 0.945.
Abstract: Anaerobic digestion process is one of the alternative
methods to convert organic waste into methane gas which is a fuel
and energy source. Activities of various kinds of microorganisms are
the main factor for anaerobic digestion which produces methane gas.
Therefore, in this study a modified Anaerobic Baffled Reactor (ABR)
with working volume of 50 liters was designed to identify the
microorganisms through biogas production. The mixture of 75%
kitchen waste and 25% sewage sludge was used as substrate.
Observations on microorganisms in the ABR showed that there exists
a small amount of protozoa (5%) and fungi (2%) in the system, but
almost 93% of the microorganism population consists of bacteria. It
is definitely clear that bacteria are responsible for anaerobic
biodegradation of kitchen waste. Results show that in the
acidification zone of the ABR (front compartments of reactor) fast
growing bacteria capable of growth at high substrate levels and
reduced pH was dominant. A shift to slower growing scavenging
bacteria that grow better at higher pH was occurring towards the end
of the reactor. Due to the ability of activity in acetate environment the
percentages of Methanococcus, Methanosarcina and Methanotrix
were higher than other kinds of methane former in the system.
Abstract: After the terrorist attack on September 11, 2001 in
U.S., the container security issue got high attention, especially by U.S.
government, which deployed a lot of measures to promote or improve
security systems. U.S. government not only enhances its national
security system, but allies with other countries against the potential
terrorist attacks in the future. For example CSI (Container Security
Initiative), it encourages foreign ports outside U.S. to become CSI
ports as a part of U.S. anti-terrorism network. Although promotion of
the security could partly reach the goal of anti-terrorism, that will
influence the efficiency of container supply chain, which is the main
concern when implementing the inspection measurements. This paper
proposes a quick estimation methodology for an inspection service
rate by a berth allocation heuristic such that the inspection activities
will not affect the original container supply chain. Theoretical and
simulation results show this approach is effective.
Abstract: The concerns about clean environment and high oil
prices driving forces for the research on alternative fuels. The
research efforts directed towards improving the performance of C.I
engines using vegetable oil as fuel. The paper deals results of
performance of a four stroke, single cylinder C.I. engine by preheated
neat Karanja oil is done from 30
o
C to 100
o
C. The performance of the
engine was studied for a speed range between 1500 to 4000 rpm, with
the engine operated under full load conditions. The performance
parameters considered for comparing are brake specific fuel
consumption, thermal efficiency, brake power, Nox emission of the
engine. The engine offers lower thermal efficiency when it is
powered by preheated neat Karanja oil at higher speed. The power
developed and Nox emission increase with the increase in the fuel
inlet temperature and the specific fuel consumption is higher than
diesel fuel operation at all elevated fuel inlet temperature.
Abstract: In this paper, the problem of finding the optimal
topological configuration of a deregulated distribution network is
considered. The new features of this paper are proposing a multiobjective
function and its application on deregulated distribution
networks for finding the optimal configuration. The multi-objective
function will be defined for minimizing total Energy Supply Costs
(ESC) and energy losses subject to load flow constraints. The
optimal configuration will be obtained by using Binary Genetic
Algorithm (BGA).The proposed method has been tested to analyze a
sample and a practical distribution networks.
Abstract: The effect of a uniform magnetic field on the
formation of drops of specific size has been investigated numerically
in a T-shaped microchannel. Previous researches indicated that the
drop sizes of secondary stream decreases, with increasing main
stream flow rate and decreasing interfacial tension. In the present
study the effect of a uniform magnetic field on the main stream is
considered, and it is proposed that by increasing the Hartmann
number, the size of the drops of the secondary stream will be
decreased.
Abstract: This paper presents a computational study of the separated flow in a planer asymmetric diffuser. The steady RANS equations for turbulent incompressible fluid flow and six turbulence closures are used in the present study. The commercial software code, FLUENT 6.3.26, was used for solving the set of governing equations using various turbulence models. Five of the used turbulence models are available directly in the code while the v2-f turbulence model was implemented via User Defined Scalars (UDS) and User Defined Functions (UDF). A series of computational analysis is performed to assess the performance of turbulence models at different grid density. The results show that the standard k-ω, SST k-ω and v2-f models clearly performed better than other models when an adverse pressure gradient was present. The RSM model shows an acceptable agreement with the velocity and turbulent kinetic energy profiles but it failed to predict the location of separation and attachment points. The standard k-ε and the low-Re k- ε delivered very poor results.
Abstract: Researchers have long had trouble in measurement of
Exchangeable Sodium Ratio (ESR) at salt-affected soils. this
parameter are often determined using laborious and time consuming
laboratory tests, but it may be more appropriate and economical to
develop a method which uses a more simple soil salinity index. The
aim of this study was to determine the relationship between
exchangeable sodium ratio (ESR) and sodium adsorption ratio (SAR)
in some salt-affected soils of Khuzestan plain. To this purpose, two
experimental areas (S1, S2) of Khuzestan province-IRAN were
selected and four treatments with three replications by series of
double rings were applied. The treatments were included 25cm,
50cm, 75cm and 100cm water application. The statistical results of
the study indicated that in order to predict soil ESR based on soil
SAR the linear regression model ESR=0.2048+0.0066 SAR
(R2=0.53) & ESR=0.0564+0.0171 SAR (R2=0.76) can be
recommended in Pilot S1 and S2 respectively.
Abstract: The present report describes the characteristics of
damages and behavior of reinforced concrete buildings during the
tsunami action. The discussion is based on the field damage survey in
selected cities located on the coast of the zone affected by the Great
East Japan Earthquake on March 11, 2011. This earthquake is the most
powerful know earthquake that has hit Japan with a magnitude 9.0 and
with epicenter located at 129 km of Sendai city (off the coast). The
earthquake triggered a destructive tsunami with run up height of up to
40 meters that mainly affect cities located on the Pacific Ocean coast of
the Tohoku region (north-east region of Japan). Reinforced concrete
buildings in general resist the tsunami without collapse however the
non-structural elements like panels and ceilings were severely
damaged. The analysis of damages has permitted to understand the
behavior of RC buildings under tsunami attack, and has also permitted
to establish recommendations for their use to take refuge from tsunami
in places where natural topography makes impossible to reach hilltops
or other safer places.
Abstract: The InAlGaN alloy has only recently began receiving
serious attention into its growth and application. High quality InGaN
films have led to the development of light emitting diodes (LEDs) and
blue laser diodes (LDs). The quaternary InAlGaN however, represents
a more versatile material since the bandgap and lattice constant can be
independently varied. We report an ultraviolet (UV) quaternary
InAlGaN multi-quantum wells (MQWs) LD study by using the
simulation program of Integrated System Engineering (ISE TCAD).
Advanced physical models of semiconductor properties were used in
order to obtain an optimized structure. The device performance which
is affected by piezoelectric and thermal effects was studied via
drift-diffusion model for carrier transport, optical gain and loss. The
optical performance of the UV LD with different numbers of quantum
wells was numerically investigated. The main peak of the emission
wavelength for double quantum wells (DQWs) was shifted from 358
to 355.8 nm when the forward current was increased. Preliminary
simulated results indicated that better output performance and lower
threshold current could be obtained when the quantum number is four,
with output power of 130 mW and threshold current of 140 mA.
Abstract: In this work, axisymetric CFD simulation of fixed bed
GTL reactor has been conducted, using computational fluid dynamics
(CFD). In fixed bed CFD modeling, when N (tube-to-particle
diameter ratio) has a large value, it is common to consider the packed
bed as a porous media. Synthesis gas (a mixture of predominantly
carbon monoxide and hydrogen) was fed to the reactor. The reactor
length was 20 cm, divided to three sections. The porous zone was in
the middle section of the reactor. The model equations were solved
employing finite volume method. The effects of particle diameter,
bed voidage, fluid velocity and bed length on pressure drop have
been investigated. Simulation results showed these parameters could
have remarkable impacts on the reactor pressure drop.
Abstract: We obtain appropriate sharp estimates for rough oscillatory integrals. Our results represent significant improvements as well as natural extensions of what was known previously.
Abstract: In this paper, the babbitting of a bearing in boiler feed pump of an electromotor has been studied. These bearings have an important role in reducing the shut down times in the pumps, compressors and turbines. The most conventional method in babbitting is casting as a melting method. The comparison between thermal spray and casting methods in babbitting shows that the thermal spraying babbitt layer has better performance and tribological behavior. The metallurgical and tribological analysis such as SEM, EDS and wet chemical analysis has been made in the Babbitt alloys and worn surfaces. Two type of babbitt materials: tinbase and lead-base babbitt was used. The benefits of thermally sprayed babbitt layers are completely clear especially in large bearings.