Abstract: This article experimentally investigates the
thermal performance of thermoelectric air-cooling module
which comprises a thermoelectric cooler (TEC) and an
air-cooling heat sink. The influences of input current and heat
load are determined. And performances under each situation
are quantified by thermal resistance analysis. Since TEC
generates Joule heat, this nature makes construction of thermal
resistance network difficult. To simplify the analysis, this
article emphasizes on the resistance heat load might meet when
passing through the device. Therefore, the thermal resistances
in this paper are to divide temperature differences by heat load.
According to the result, there exists an optimum input current
under every heating power. In this case, the optimum input
current is around 6A or 7A. The performance of the heat sink
would be improved with TEC under certain heating power and
input current, especially at a low heat load. According to the
result, the device can even make the heat source cooler than the
ambient. However, TEC is not always effective at every heat
load and input current. In some situation, the device works
worse than the heat sink without TEC. To determine the
availability of TEC, this study figures out the effective
operating region in which the TEC air-cooling module works
better than the heat sink without TEC. The result shows that
TEC is more effective at a lower heat load. If heat load is too
high, heat sink with TEC will perform worse than without TEC.
The limit of this device is 57W. Besides, TEC is not helpful if
input current is too high or too low. There is an effective range
of input current, and the range becomes narrower when the heat
load grows.
Abstract: The three-time-scale plant model of a wind power
generator, including a wind turbine, a flexible vertical shaft, a Variable
Inertia Flywheel (VIF) module, an Active Magnetic Bearing (AMB)
unit and the applied wind sequence, is constructed. In order to make
the wind power generator be still able to operate as the spindle speed
exceeds its rated speed, the VIF is equipped so that the spindle speed
can be appropriately slowed down once any stronger wind field is
exerted. To prevent any potential damage due to collision by shaft
against conventional bearings, the AMB unit is proposed to regulate
the shaft position deviation. By singular perturbation order-reduction
technique, a lower-order plant model can be established for the
synthesis of feedback controller. Two major system parameter
uncertainties, an additive uncertainty and a multiplicative uncertainty,
are constituted by the wind turbine and the VIF respectively.
Frequency Shaping Sliding Mode Control (FSSMC) loop is proposed
to account for these uncertainties and suppress the unmodeled
higher-order plant dynamics. At last, the efficacy of the FSSMC is
verified by intensive computer and experimental simulations for
regulation on position deviation of the shaft and counter-balance of
unpredictable wind disturbance.
Abstract: The main focus of the work was concerned with hydrodynamic and thermal analysis of the plate heat exchanger channel with corrugation patterns suggested to be triangular, sinusoidal, and square corrugation. This study was to numerically model and validate the triangular corrugated channel with dimensions/parameters taken from open literature, and then model/analyze both sinusoidal, and square corrugated channel referred to the triangular model. Initially, 2D modeling with local extensive analysis for triangular corrugated channel was carried out. By that, all local pressure drop, wall shear stress, friction factor, static temperature, heat flux, Nusselt number, and surface heat coefficient, were analyzed to interpret the hydrodynamic and thermal phenomena occurred in the flow. Furthermore, in order to facilitate confidence in this model, a comparison between the values predicted, and experimental results taken from literature for almost the same case, was done. Moreover, a holistic numerical study for sinusoidal and square channels together with global comparisons with triangular corrugation under the same condition, were handled. Later, a comparison between electric, and fluid cooling through varying the boundary condition was achieved. The constant wall temperature and constant wall heat flux boundary conditions were employed, and the different resulted Nusselt numbers as a consequence were justified. The results obtained can be used to come up with an optimal design, a 'compromise' between heat transfer and pressure drop.
Abstract: This paper presents an investigation of the power
penalties imposed by four-wave mixing (FWM) on G.652 (Single-
Mode Fiber - SMF), G.653 (Dispersion-Shifted Fiber - DSF), and
G.655 (Non-Zero Dispersion-Shifted Fiber - NZDSF) compliant
fibers, considering the DWDM grids suggested by the ITU-T
Recommendations G.692, and G.694.1, with uniform channel
spacing of 100, 50, 25, and 12.5 GHz. The mathematical/numerical
model assumes undepleted pumping, and shows very clearly the
deleterious effect of FWM on the performance of DWDM systems,
measured by the signal-to-noise ratio (SNR). The results make it
evident that non-uniform channel spacing is practically mandatory
for WDM systems based on DSF fibers.
Abstract: In this paper, we consider the almost periodic solutions of a discrete cooperation system with feedback controls. Assuming that the coefficients in the system are almost periodic sequences, we obtain the existence and uniqueness of the almost periodic solution which is uniformly asymptotically stable.
Abstract: Magnesium is used implant material potentially for
non-toxicity to the human body. Due to the excellent
bio-compatibility, Mg alloys is applied to implants avoiding removal
second surgery. However, it is found commercial magnesium alloys
including aluminum has low corrosion resistance, resulting
subcutaneous gas bubbles and consequently the approach as
permanent bio-materials. Generally, Aluminum is known to pollution
substance, and it raises toxicity to nervous system. Therefore
especially Mg-35Zn-3Ca alloy is prepared for new biodegradable
materials in this study. And the pulsed power is used in
constant-current mode of DC power kinds of anodization. Based on
the aforementioned study, it examines corrosion resistance and
biocompatibility by effect of current and frequency variation. The
surface properties and thickness were compared using scanning
electronic microscopy. Corrosion resistance was assessed via
potentiodynamic polarization and the effect of oxide layer on the body
was assessed cell viability. Anodized Mg-35Zn-3Ca alloy has good
biocompatibility in vitro by current and frequency variation.
Abstract: One important problem in today organizations is the
existence of non-integrated information systems, inconsistency and
lack of suitable correlations between legacy and modern systems.
One main solution is to transfer the local databases into a global one.
In this regards we need to extract the data structures from the legacy
systems and integrate them with the new technology systems. In
legacy systems, huge amounts of a data are stored in legacy
databases. They require particular attention since they need more
efforts to be normalized, reformatted and moved to the modern
database environments. Designing the new integrated (global)
database architecture and applying the reverse engineering requires
data normalization. This paper proposes the use of database reverse
engineering in order to integrate legacy and modern databases in
organizations. The suggested approach consists of methods and
techniques for generating data transformation rules needed for the
data structure normalization.
Abstract: This paper addresses issues of integral steering of
vehicles with two steering axles, where the rear wheels are pivoted in
the direction of the front wheels, but also in the opposite direction.
The steering box of the rear axle is presented with simple linkages
(single contour) that correlate the pivoting of the rear wheels
according to the direction of the front wheels, respectively to the
rotation angle of the steering wheel. The functionality of the system
is analyzed – the extent to which the requirements of the integral
steering are met by the considered/proposed mechanisms. The paper
highlights the quality of the single contour linkages, with two driving
elements for meeting these requirements, emphasizing diagrams of
mechanisms with 2 driving elements. Cam variants are analyzed and
proposed for the rear axle steering box. Cam profiles are determined
by various factors.
Abstract: The study of the transport coefficients in electronic
devices is currently carried out by analytical and empirical models.
This study requires several simplifying assumptions, generally
necessary to lead to analytical expressions in order to study the
different characteristics of the electronic silicon-based devices.
Further progress in the development, design and optimization of
Silicon-based devices necessarily requires new theory and modeling
tools. In our study, we use the PSO (Particle Swarm Optimization)
technique as a computational tool to develop analytical approaches in
order to study the transport phenomenon of the electron in crystalline
silicon as function of temperature and doping concentration. Good
agreement between our results and measured data has been found.
The optimized analytical models can also be incorporated into the
circuits simulators to study Si-based devices without impact on the
computational time and data storage.
Abstract: This paper proposes a modeling methodology for the
development of data analysis solution. The Author introduce the
approach to address data warehousing issues at the at enterprise level.
The methodology covers the process of the requirements eliciting and
analysis stage as well as initial design of data warehouse. The paper
reviews extended business process model, which satisfy the needs of
data warehouse development. The Author considers that the use of
business process models is necessary, as it reflects both enterprise
information systems and business functions, which are important for
data analysis. The Described approach divides development into
three steps with different detailed elaboration of models. The
Described approach gives possibility to gather requirements and
display them to business users in easy manner.
Abstract: Twist drills are geometrical complex tools and thus various researchers have adopted different mathematical and experimental approaches for their simulation. The present paper acknowledges the increasing use of modern CAD systems and using the API (Application Programming Interface) of a CAD system, drilling simulations are carried out. The developed DRILL3D software routine, creates parametrically controlled tool geometries and using different cutting conditions, achieves the generation of solid models for all the relevant data involved (drilling tool, cut workpiece, undeformed chip). The final data derived, consist a platform for further direct simulations regarding the determination of cutting forces, tool wear, drilling optimizations etc.
Abstract: Automatic face detection is a complex problem in
image processing. Many methods exist to solve this problem such as
template matching, Fisher Linear Discriminate, Neural Networks,
SVM, and MRC. Success has been achieved with each method to
varying degrees and complexities. In proposed algorithm we used
upright, frontal faces for single gray scale images with decent
resolution and under good lighting condition. In the field of face
recognition technique the single face is matched with single face
from the training dataset. The author proposed a neural network
based face detection algorithm from the photographs as well as if any
test data appears it check from the online scanned training dataset.
Experimental result shows that the algorithm detected up to 95%
accuracy for any image.
Abstract: Online trading is an alternative to conventional shopping method. People trade goods which are new or pre-owned before. However, there are times when a user is not able to search the items wanted online. This is because the items may not be posted as yet, thus ending the search. Conventional search mechanism only works by searching and matching search criteria (requirement) with data available in a particular database. This research aims to match current search requirements with future postings. This would involve the time factor in the conventional search method. A Car Matching Alert System (CMAS) prototype was developed to test the matching algorithm. When a buyer-s search returns no result, the system saves the search and the buyer will be alerted if there is a match found based on future postings. The algorithm developed is useful and as it can be applied in other search context.
Abstract: The dynamic behaviour of a four-bar linkage driven by a velocity controlled DC motor is discussed in the paper. In particular the author presents the results obtained by means of a specifically developed software, which implements the mathematical models of all components of the system (linkage, transmission, electric motor, control devices). The use of this software enables a more efficient design approach, since it allows the designer to check, in a simple and immediate way, the dynamic behaviour of the mechanism, arising from different values of the system parameters.
Abstract: In designing of condensers, the prediction of pressure
drop is as important as the prediction of heat transfer coefficient.
Modeling of two phase flow, particularly liquid – vapor flow under
diabatic conditions inside a horizontal tube using CFD analysis is
difficult with the available two phase models in FLUENT due to
continuously changing flow patterns. In the present analysis, CFD
analysis of two phase flow of refrigerants inside a horizontal tube of
inner diameter, 0.0085 m and 1.2 m length is carried out using
homogeneous model under adiabatic conditions. The refrigerants
considered are R22, R134a and R407C. The analysis is performed at
different saturation temperatures and at different flow rates to
evaluate the local frictional pressure drop. Using Homogeneous
model, average properties are obtained for each of the refrigerants
that is considered as single phase pseudo fluid. The so obtained
pressure drop data is compared with the separated flow models
available in literature.
Abstract: This paper presents the experimental results of a
single cylinder Enfield engine using an electronically controlled fuel
injection system which was developed to carry out exhaustive tests
using neat CNG, and mixtures of hydrogen in compressed natural gas
(HCNG) as 0, 5, 10, 15 and 20% by energy. Experiments were
performed at 2000 and 2400 rpm with wide open throttle and varying
the equivalence ratio. Hydrogen which has fast burning rate, when
added to compressed natural gas, enhances its flame propagation rate.
The emissions of HC, CO, decreased with increasing percentage of
hydrogen but NOx was found to increase. The results indicated a
marked improvement in the brake thermal efficiency with the
increase in percentage of hydrogen added. The improved thermal
efficiency was clearly observed to be more in lean region as
compared to rich region. This study is expected to reduce vehicular
emissions along with increase in thermal efficiency and thus help in
reduction of further environmental degradation.
Abstract: Logistics outsourcing is a growing trend and measuring its performance, a challenge. It must be consistent with the objectives set for logistics outsourcing, but we have found no objective-based performance measurement system. We have conducted a comprehensive review of the specialist literature to cover this gap, which has led us to identify and define these objectives. The outcome is that we have obtained a list of the most relevant objectives and their descriptions. This will enable us to analyse in a future study whether the indicators used for measuring logistics outsourcing performance are consistent with the objectives pursued with the outsourcing. If this is not the case, a proposal will be made for a set of financial and operational indicators to measure performance in logistics outsourcing that take the goals being pursued into account.
Abstract: A active inductor in CMOS techonology with a supply voltage of 1.8V is presented. The value of the inductance L can be in the range from 0.12nH to 0.25nH in high frequency(HF). The proposed active inductor is designed in TSMC 0.18-um CMOS technology. The power dissipation of this inductor can retain constant at all operating frequency bands and consume around 20mW from 1.8V power supply. Inductors designed by integrated circuit occupy much smaller area, for this reason,attracted researchers attention for more than decade. In this design we used Advanced Designed System (ADS) for simulating cicuit.
Abstract: PARADIGMA (PARticipative Approach to DIsease
Global Management) is a pilot project which aims to develop and
demonstrate an Internet based reference framework to share scientific
resources and findings in the treatment of major diseases.
PARADIGMA defines and disseminates a common methodology and
optimised protocols (Clinical Pathways) to support service functions
directed to patients and individuals on matters like prevention, posthospitalisation
support and awareness. PARADIGMA will provide a
platform of information services - user oriented and optimised
against social, cultural and technological constraints - supporting the
Health Care Global System of the Euro-Mediterranean Community
in a continuous improvement process.
Abstract: Software effort estimation is the process of predicting
the most realistic use of effort required to develop or maintain
software based on incomplete, uncertain and/or noisy input. Effort
estimates may be used as input to project plans, iteration plans,
budgets. There are various models like Halstead, Walston-Felix,
Bailey-Basili, Doty and GA Based models which have already used
to estimate the software effort for projects. In this study Statistical
Models, Fuzzy-GA and Neuro-Fuzzy (NF) Inference Systems are
experimented to estimate the software effort for projects. The
performances of the developed models were tested on NASA
software project datasets and results are compared with the Halstead,
Walston-Felix, Bailey-Basili, Doty and Genetic Algorithm Based
models mentioned in the literature. The result shows that the NF
Model has the lowest MMRE and RMSE values. The NF Model
shows the best results as compared with the Fuzzy-GA based hybrid
Inference System and other existing Models that are being used for
the Effort Prediction with lowest MMRE and RMSE values.