Abstract: This paper reports on the theoretical performance
analysis of the 1.3 μm In0.42Ga0.58As /In0.26Ga0.74As multiple quantum
well (MQW) vertical cavity surface emitting laser (VCSEL) on the
ternary In0.31Ga0.69As substrate. The output power of 2.2 mW has
been obtained at room temperature for 7.5 mA injection current. The
material gain has been estimated to be ~3156 cm-1 at room
temperature with the injection carrier concentration of 2×1017 cm-3.
The modulation bandwidth of this laser is measured to be 9.34 GHz
at room temperature for the biasing current of 2 mA above the
threshold value. The outcomes reveal that the proposed InGaAsbased
MQW laser is the promising one for optical communication
system.
Abstract: Zeolite A and MCM-41 have extensive applications in basic science, petrochemical science, energy conservation/storage, medicine, chemical sensor, air purification, environmentally benign composite structure and waste remediation. However, the use of zeolite A and MCM-41 in these areas, especially environmental remediation, are restricted due to prohibitive production cost. Efficient recycling of and resource recovery from coal fly ash has been a major topic of current international research interest, aimed at achieving sustainable development of human society from the viewpoints of energy, economy, and environmental strategy. This project reported an original, novel, green and fast methods to produce nano-porous zeolite A and MCM-41 materials from coal fly ash. For zeolite A, this novel production method allows a reduction by half of the total production time while maintaining a high degree of crystallinity of zeolite A which exists in a narrower particle size distribution. For MCM-41, this remarkably green approach, being an environmentally friendly process and reducing generation of toxic waste, can produce pure and long-range ordered MCM-41 materials from coal fly ash. This approach took 24 h at 25 oC to produce 9 g of MCM-41 materials from 30 g of the coal fly ash, which is the shortest time and lowest reaction temperature required to produce pure and ordered MCM-41 materials (having the largest internal surface area) compared to the values reported in the literature. Performance evaluation of the produced zeolite A and MCM-41 materials in wastewater treatment and air pollution control were reported. The residual fly ash was also converted to zeolite Na-P1 which showed good performance in removal of multi-metal ions in wastewater. In wastewater treatment, compared to commercial-grade zeolite A, adsorbents produced from coal fly ash were effective in removing multi heavy metal ions in water and could be an alternative material for treatment of wastewater. In methane emission abatement, the zeolite A (produced from coal fly ash) achieved similar methane removal efficiency compared to the zeolite A prepared from pure chemicals. This report provides the guidance for production of zeolite A and MCM-41 from coal fly ash by a cost-effective approach which opens potential applications of these materials in environmental industry. Finally, environmental and economic aspects of production of zeolite A and MCM-41 from coal fly ash were discussed.
Abstract: This article presents the boundary conditions for the problem of turbulent supersonic gas flow in a plane channel with a perpendicular injection jets. The non-reflection boundary conditions for direct modeling of compressible viscous gases are studied. A formulation using the NSCBC (Navier- Stocks characteristic boundary conditions) through boundaries is derived for the subsonic inflow and subsonic non-reflection outflow situations. Verification of the constructed algorithm of boundary conditions is carried out by solving a test problem of perpendicular sound of jets injection into a supersonic gas flow in a plane channel.
Abstract: This paper presents features that characterize power
quality disturbances from recorded voltage waveforms using wavelet
transform. The discrete wavelet transform has been used to detect
and analyze power quality disturbances. The disturbances of interest
include sag, swell, outage and transient. A power system network has
been simulated by Electromagnetic Transients Program. Voltage
waveforms at strategic points have been obtained for analysis, which
includes different power quality disturbances. Then wavelet has been
chosen to perform feature extraction. The outputs of the feature
extraction are the wavelet coefficients representing the power quality
disturbance signal. Wavelet coefficients at different levels reveal the
time localizing information about the variation of the signal.
Abstract: We consider a two-way relay network where two sources exchange information. A relay helps the two sources exchange information using the decode-and-XOR-forward protocol. We investigate the power minimization problem with minimum rate constraints. The system needs two time slots and in each time slot the required rate pair should be achievable. The power consumption is minimized in each time slot and we obtained the closed form solution. The simulation results confirm that the proposed power allocation scheme consumes lower total power than the conventional schemes.
Abstract: A systematic way to derive the conserved quantities for the axisymmetric liquid jet, free jet and wall jet using conservation laws is presented. The flow in axisymmetric jets is governed by Prandtl-s momentum boundary layer equation and the continuity equation. The multiplier approach is used to construct a basis of conserved vectors for the system of two partial differential equations for the two velocity components. The basis consists of two conserved vectors. By integrating the corresponding conservation laws across the jet and imposing the boundary conditions, conserved quantities are derived for the axisymmetric liquid and free jet. The multiplier approach applied to the third-order partial differential equation for the stream function yields two local conserved vectors one of which is a non-local conserved vector for the system. One of the conserved vectors gives the conserved quantity for the axisymmetric free jet but the conserved quantity for the wall jet is not obtained from the second conserved vector. The conserved quantity for the axisymmetric wall jet is derived from a non-local conserved vector of the third-order partial differential equation for the stream function. This non-local conserved vector for the third-order partial differential equation for the stream function is obtained by using the stream function as multiplier.
Abstract: In this paper motion analysis on a winding
stair-climbing is investigated using our proposed rotational arm type
of robotic wheelchair. For now, the robotic wheelchair is operated in
an open mode to climb winding stairs by a dynamic turning, therefore,
the dynamics model is required to ensure a passenger-s safety.
Equations of motion based on the skid-steering analysis are developed
for the trajectory planning and motion analysis on climbing winding
stairs. Since the robotic wheelchair must climb a winding staircase
stably, the winding trajectory becomes a constraint equation to be
followed, and the Baumgarte-s method is used to solve for the
constrained dynamics equations. Experimental results validate the
behavior of the prototype as it climbs a winding stair.
Abstract: Present communication deals with general
distribution and diversification of Monogenean families parasitizing
different freshwater fish families of India. Levels of monogenean
parasitism and their diversity are significantly greater in Indian fishes.
The most monogeneans parasitized family of fish is Cyprinidae and
most dactylogyrids parasitise cyprinids. The family dactylogyridae
has more species than any other monogenean family and frequently
associated with cyprinid, silurids and bagrids families. Of the various
52 families of freshwater fishes from India, only the Anguillidae,
Balitoridae, Chacidae, Chanidae, Channidae, Cobitidae, Coiidae,
Erethistidae, Megalopidae, Pristidae, Psilorhynchidae, Salmonidae,
Schileidae, Sparidae, Synodontidae and Terapontidae were found to
be free of infection with monogeneans. The present study takes a
broad look at monogenean diversity in the freshwater fishes of India.
Abstract: In this paper, a heuristic method for simultaneous
rescue robot path-planning and mission scheduling is introduced
based on project management techniques, multi criteria decision
making and artificial potential fields path-planning. Groups of
injured people are trapped in a disastrous situation. These people are
categorized into several groups based on the severity of their
situation. A rescue robot, whose ultimate objective is reaching
injured groups and providing preliminary aid for them through a path
with minimum risk, has to perform certain tasks on its way towards
targets before the arrival of rescue team. A decision value is assigned
to each target based on the whole degree of satisfaction of the criteria
and duties of the robot toward the target and the importance of
rescuing each target based on their category and the number of
injured people. The resulted decision value defines the strength of the
attractive potential field of each target. Dangerous environmental
parameters are defined as obstacles whose risk determines the
strength of the repulsive potential field of each obstacle. Moreover,
negative and positive energies are assigned to the targets and
obstacles, which are variable with respects to the factors involved.
The simulation results show that the generated path for two cases
studies with certain differences in environmental conditions and
other risk factors differ considerably.
Abstract: Educational institutions increasingly adopt the
students-as-customers concept to satisfy their students.
Understanding students- perspectives on the use of this business
concept in educational institutions is necessary for the institutions to
effectively align these perspectives with their management practice.
The study investigates whether students in technology and business
disciplines have significantly different attitudes toward using the
students-as-customers concept in educational institutions and
explores the impact of treating students as customers in technology
disciplines under students- perspectives. The results from
quantitative and qualitative data analyses show that technology
students, in contrast to business students, fairly disagree with
educational institutions to treat students as customers. Treating
students as customers in technology disciplines will have a negative
influence on teaching performance, instructor-student relationships
and educational institutions- aim, but a positive influence on service
quality in educational institutions. The paper discusses the findings
and concludes with implications and limitations of the study.
Abstract: This paper addresses the stabilization issues for a class of uncertain switched neutral systems with nonlinear perturbations. Based on new classes of piecewise Lyapunov functionals, the stability assumption on all the main operators or the convex combination of coefficient matrices is avoid, and a new switching rule is introduced to stabilize the neutral systems. The switching rule is designed from the solution of the so-called Lyapunov-Metzler linear matrix inequalities. Finally, three simulation examples are given to demonstrate the significant improvements over the existing results.
Abstract: The main objectives of this study are to inspect and
identify any damage of jaimusi highway prestressed concrete bridge
after repair and strengthening of damaged structural members and to
evaluate the performance of the bridge structural members by
adopting static load test. Inspection program after repair and
strengthening includes identifying and evaluating the structural
members of bridge such as T-shape cantilever structure, hanging
beams, corbels, external tendons, anchor beams, sticking steel plate,
and piers. The results of inspection show that the overall state of the
bridge structural member after repair and strengthening is good. The
results of rebound test of concrete strength show that the average
strength of concrete is 46.31Mpa. Whereas, the average value of
concrete strength of anchor beam is 49.82Mpa. According to the
results of static load test, the experimental values are less than
theoretical values of internal forces, deflection, and strain, indicating
that the stiffness of the experimental structure, overall deformation
and integrity satisfy the designed standard and the working
performance is good, and the undertaking capacity has a certain
surplus. There is not visible change in the length and width of cracks
and there are not new cracks under experimental load.
Abstract: In this paper the fatigue crack initiation location of double shear lap joints, treated by interference fit and bolt clamping, have been investigated both experimentally and numerically. To do so, using the fracture section of available fatigue tested specimens of interference fitted and torque tightened Aluminum 2024-T3 plates, the crack initiation location was determined. The stress distribution attained from the finite element analysis was used to help explain the results observed in the experimental tests. The results showed that the fatigue crack initiation location changes from top and mid plane at the hole edge to somewhere far from the hole edge (stress concentration region) in different combination of clamping force, interference fit size and applied cyclic load ranges. It is worth mentioning that the fatigue crack initiation location affects the fatigue life of the specimens too.
Abstract: This paper presents the experiment results of investigating the effects of adding various types and proportions of fibre on mechanical strength and permeability characteristics of recycled aggregate concrete (RAC), which was produced with treated coarse recycled concrete aggregate (RCA). Two types of synthetic fibres (i.e., barchip and polypropylene fibre) with various volume fractions were added to the RAC, which was calculated by the weight of the cement. The hardened RAC properties such as compressive strength, flexural strength, ultrasonic pulse velocity, water absorption and total porosity at the curing ages of 7 and 28 days were evaluated and compared with the properties of the control specimens. Results indicate that the treated coarse RCA enhances the mechanical strength and permeability properties of RAC and adding barchip fibre further optimises the results. Adding 1.2% barchip fibre has the best effect on the mechanical strength performance of the RAC.
Abstract: Using finite element method (FEM), the elastic
new strain-concentration factor (SNCF) of cylindrical bars
with circumferential flat-bottom groove is studied. This new
SNCF has been defined under triaxial stress state. The
employed specimens have constant groove depth with net
section and gross diameters of 10.0 and 16.7 mm,
respectively. The length of flatness ao has been varied form
0.0 ~12.5 mm to study the elastic SNCF of this type of
geometrical irregularities. The results that the elastic new
SNCF rapidly drops from its elastic value of the groove with
ao = 0.0, i.e. circumferential U-notch, and reaches minimum
value at ao = 2 mm. After that the elastic new SNCF becomes
nearly constant with increasing flatness length (ao). The value
of tensile load at yielding at the groove root increases with
increasing ao. The current results show that severity of the
notch decreases with increasing flatness length ao.
Abstract: The gamma radiation in samples of a variety of
natural tiling rocks (granites) produced and imported in Iran use in
the building industry was measured, employing high-resolution
Gamma-ray spectroscopy. The rock samples were pulverized, sealed
in 0.5 liter plastic Marinelli beakers, and measured in the laboratory
with an accumulating time between 50000 and 80000 second each.
From the measured Gamma-ray spectra, activity concentrations were
determined for 232Th (range from 6.5 to 172.2 Bq kg-1), 238U (from
7.5 to 178.1 Bq kg-1 ),226Ra( from 3.8 to 94.2 Bq kg-1 ) 40K (from
556.9 to 1539.2 Bq kg-1). From the 29 samples measured in this
study, “Nehbndan ( Berjand )" appears to present the highest
concentrations for 232Th,“Big Red Flower (China) "for 238U , “
Khoram dareh" for 226 Ra and “ Peranshahr" for 40K , respectively.
Abstract: This paper discusses the use of explorative data
mining tools that allow the educator to explore new relationships
between reported learning experiences and actual activities,
even if there are multiple dimensions with a large number
of measured items. The underlying technology is based on
the so-called Compendium Platform for Reproducible Computing
(http://www.freestatistics.org) which was built on top the computational
R Framework (http://www.wessa.net).
Abstract: The role of knowledge is a determinative factor in the
life of economy and society. To determine knowledge is not an easy
task yet the real task is to determine the right knowledge. From this
view knowledge is a sum of experience, ideas and cognitions which
can help companies to remain in markets and to realize a maximum
profit. At the same time changes of circumstances project in advance
that contents and demands of the right knowledge are changing. In
this paper we will analyse a special segment on the basis of an
empirical survey. We investigated the behaviour and strategies of
small and medium sized enterprises (SMEs) in the area of
knowledge-handling. This survey was realized by questionnaires and
wide range statistical methods were used during processing. As a
result we will show how these companies are prepared to operate in a
knowledge-based economy and in which areas they have prominent
deficiencies.
Abstract: The protein domain structure has been widely used as the most informative sequence feature to computationally predict protein-protein interactions. However, in a recent study, a research group has reported a very high accuracy of 94% using hydrophobicity feature. Therefore, in this study we compare and verify the usefulness of protein domain structure and hydrophobicity properties as the sequence features. Using the Support Vector Machines (SVM) as the learning system, our results indicate that both features achieved accuracy of nearly 80%. Furthermore, domains structure had receiver operating characteristic (ROC) score of 0.8480 with running time of 34 seconds, while hydrophobicity had ROC score of 0.8159 with running time of 20,571 seconds (5.7 hours). These results indicate that protein-protein interaction can be predicted from domain structure with reliable accuracy and acceptable running time.
Abstract: This paper is the tomographic images reconstruction
simulation for defects detection in specimen. The specimen is the
thin cylindrical steel contained with low density materials. The
defects in material are simulated in three shapes.The specimen image
function will be transformed to projection data. Radon transform and
its inverse provide the mathematical for reconstructing tomographic
images from projection data. The result of the simulation show that
the reconstruction images is complete for defect detection.