Abstract: The present study conducted experimental investigation on combustion and emission characteristics of compression ignition engine using diesel as pilot fuel and methane, hydrogen and methane/hydrogen mixture as gaseous fuels at 1800 rev min-1. The effect of gaseous fuel on peak cylinder pressure and heat release is modest at low to medium loads. At high load, the high combustion temperature and high quantity of pilot fuel contribute to better combustion efficiency for all kinds of gaseous fuels and increases the peak cylinder pressure. Enrichment of hydrogen in methane gradually increases the peak cylinder pressure. The brake thermal efficiency increases with higher hydrogen fraction at lower loads. Hydrogen addition in methane contributed to a proportional reduction of CO/CO2/HC emission without penalty of NOx. For particulate emission, methane and hydrogen, could both suppress the particle emission. 30% hydrogen fraction in methane is observed to be best in reducing the particulate emission.
Abstract: This current research focused on development of degradable starch based packaging film with enhanced mechanical properties. A series of low density polyethylene (LDPE)/tapioca starch compounds with various tapioca starch contents were prepared by twin screw extrusion with the addition of maleic anhydride grafted polyethylene as compatibilizer. Palm cooking oil was used as processing aid to ease the blown film process, thus, degradable film can be processed via conventional blown film machine. Studies on their characteristics, mechanical properties and biodegradation were carried out by Fourier Transform Infrared (FTIR) spectroscopy and optical properties, tensile test and exposure to fungi environment respectively. The presence of high starch contents had an adverse effect on the tensile properties of LDPE/tapioca starch blends. However, the addition of compatibilizer to the blends improved the interfacial adhesion between the two materials, hence, improved the tensile properties of the films. High content of starch amount also was found to increase the rate of biodegradability of LDPE/tapioca starch films. It can be proved by exposure of the film to fungi environment. A growth of microbes colony can be seen on the surface of LDPE/tapioca starch film indicates that the granular starch present on the surface of the polymer film is attacked by microorganisms, until most of it is assimilated as a carbon source.
Abstract: An efficient parallel form in digital signal processor can improve the algorithm performance. The butterfly structure is an important role in fast Fourier transform (FFT), because its symmetry form is suitable for hardware implementation. Although it can perform a symmetric structure, the performance will be reduced under the data-dependent flow characteristic. Even though recent research which call as novel memory reference reduction methods (NMRRM) for FFT focus on reduce memory reference in twiddle factor, the data-dependent property still exists. In this paper, we propose a parallel-computing approach for FFT implementation on digital signal processor (DSP) which is based on data-independent property and still hold the property of low-memory reference. The proposed method combines final two steps in NMRRM FFT to perform a novel data-independent structure, besides it is very suitable for multi-operation-unit digital signal processor and dual-core system. We have applied the proposed method of radix-2 FFT algorithm in low memory reference on TI TMSC320C64x DSP. Experimental results show the method can reduce 33.8% clock cycles comparing with the NMRRM FFT implementation and keep the low-memory reference property.
Abstract: Sorghum flour was supplemented with 15 and 30%
chickpea flour. Sorghum flour and the supplement were fermented at
35 oC for 0, 8, 16, and 24 h. Changes in pH, titrable acidity, total
soluble solids, protein content, in vitro protein digestibility and
amino acid composition were investigated during fermentation and/or
after supplementation of sorghum flour with chickpea. The pH of the
fermenting material decreased sharply with a concomitant increase in
the titrable acidity. The total soluble solids remained unchanged with
progressive fermentation time. The protein content of sorghum
cultivar was found to be 9.27 and that of chickpea was 22.47%. The
protein content of sorghum cultivar after supplementation with15 and
30% chickpea was significantly (P ≤ 0.05) increased to 11.78 and
14.55%, respectively. The protein digestibility also increased after
fermentation from 13.35 to 30.59 and 40.56% for the supplements,
respectively. Further increment in protein content and digestibility
was observed when supplemented and unsupplemented samples were
fermented for different periods of time. Cooking of fermented
samples was found to increase the protein content slightly and
decreased digestibility for both supplements. Amino acid content of
fermented and fermented and cooked supplements was determined.
Supplementation was found to increase the lysine and therionine
content. Cooking following fermentation decreased lysine,
isoleucine, valine and sulfur containg amino acids.
Abstract: The Beijing road traffic system, as a typical huge
urban traffic system, provides a platform for analyzing the complex
characteristics and the evolving mechanisms of urban traffic systems.
Based on dynamic network theory, we construct the dynamic model
of the Beijing road traffic system in which the dynamical properties
are described completely. Furthermore, we come into the conclusion
that urban traffic systems can be viewed as static networks, stochastic
networks and complex networks at different system phases by
analyzing the structural randomness. As well as, we demonstrate the
evolving process of the Beijing road traffic network based on real
traffic data, validate the stochastic characteristics and the scale-free
property of the network at different phases
Abstract: A control system design with Characteristic Ratio
Assignment (CRA) is proven that effective for SISO control design.
But the control system design for MIMO via CRA is not concrete
procedure. In this paper presents the control system design method
for quadruple-tank process via CRA. By using the decentralized
method for both minimum phase and non-minimum phase are made.
The results from PI and PID controller design via CRA can be
illustrated the validity of our approach by MATLAB.
Abstract: It is known that the heart interacts with and adapts to its venous and arterial loading conditions. Various experimental studies and modeling approaches have been developed to investigate the underlying mechanisms. This paper presents a model of the left ventricle derived based on nonlinear stress-length myocardial characteristics integrated over truncated ellipsoidal geometry, and second-order dynamic mechanism for the excitation-contraction coupling system. The results of the model presented here describe the effects of the viscoelastic damping element of the electromechanical coupling system on the hemodynamic response. Different heart rates are considered to study the pacing effects on the performance of the left-ventricle against constant preload and afterload conditions under various damping conditions. The results indicate that the pacing process of the left ventricle has to take into account, among other things, the viscoelastic damping conditions of the myofilament excitation-contraction process. The effects of left ventricular dimensions on the hemdynamic response have been examined. These effects are found to be different at different viscoelastic and pacing conditions.
Abstract: The voltage/current characteristics and the effect of
NO2 gas on the electrical conductivity of a PbPc gas sensor array is
investigated. The gas sensor is manufactured using vacuum
deposition of gold electrodes on sapphire substrate with the leadphathalocyanine
vacuum sublimed on the top of the gold electrodes.
Two versions of the PbPc gas sensor array are investigated. The
tested types differ in the gap sizes between the deposited gold
electrodes. The sensors are tested at different temperatures to account
for conductivity changes as the molecular adsorption/desorption rate
is affected by heat. The obtained results found to be encouraging as
the sensors shoed stability and sensitivity towards low concentration
of applied NO2 gas.
Abstract: This paper aims at a new challenge of customer
satisfaction on mobile customer relationship management. In this
paper presents a conceptualization of mCRM on its unique
characteristics of customer satisfaction. Also, this paper develops an
empirical framework in conception of customer satisfaction in
mCRM. A single-case study is applied as the methodology. In order to
gain an overall view of the empirical case, this paper accesses to
invisible and important information of company in this investigation.
Interview is the key data source form the main informants of the
company through which the issues are identified and the proposed
framework is built. It supports the development of customer
satisfaction in mCRM; links this theoretical framework into practice;
and provides the direction for future research. Therefore, this paper is
very useful for the industries as it helps them to understand how
customer satisfaction changes the mCRM structure and increase the
business competitive advantage. Finally, this paper provides a
contribution in practice by linking a theoretical framework in
conception of customer satisfaction in mCRM for companies to a
practical real case.
Abstract: This paper presents an algorithm to estimate the parameters of two closely spaced sinusoids, providing a frequency resolution that is more than 800 times greater than that obtained by using the Discrete Fourier Transform (DFT). The strategy uses a highly optimized grid search approach to accurately estimate frequency, amplitude and phase of both sinusoids, keeping at the same time the computational effort at reasonable levels. The proposed method has three main characteristics: 1) a high frequency resolution; 2) frequency, amplitude and phase are all estimated at once using one single package; 3) it does not rely on any statistical assumption or constraint. Potential applications to this strategy include the difficult task of resolving coincident partials of instruments in musical signals.
Abstract: Network-Centric Air Defense Missile Systems
(NCADMS) represents the superior development of the air defense
missile systems and has been regarded as one of the major research
issues in military domain at present. Due to lack of knowledge and
experience on NCADMS, modeling and simulation becomes an effective
approach to perform operational analysis, compared with
those equation based ones. However, the complex dynamic interactions
among entities and flexible architectures of NCADMS put forward
new requirements and challenges to the simulation framework
and models. ABS (Agent-Based Simulations) explicitly addresses
modeling behaviors of heterogeneous individuals. Agents have capability
to sense and understand things, make decisions, and act on the
environment. They can also cooperate with others dynamically to
perform the tasks assigned to them. ABS proves an effective approach
to explore the new operational characteristics emerging in
NCADMS. In this paper, based on the analysis of network-centric
architecture and new cooperative engagement strategies for
NCADMS, an agent-based simulation framework by expanding the
simulation framework in the so-called System Effectiveness Analysis
Simulation (SEAS) was designed. The simulation framework specifies
components, relationships and interactions between them, the
structure and behavior rules of an agent in NCADMS. Based on scenario
simulations, information and decision superiority and operational
advantages in NCADMS were analyzed; meanwhile some
suggestions were provided for its future development.
Abstract: This research aimed to study correlation between
work satisfaction and organization core value of officers in
Waterworks Authority, Bangkean Branch. Sample group of the study
was 112 officers who worked in the Waterworks Authority,
Bangkean Branch. Questionnaires were employed as a research tools,
while, Percentage, Mean, Standard Deviation, T-test, One-way
ANOVA, and Pearson Product Moment Correlation were claimed as
statistics used in this study. Researcher found that overall and
individual aspects of work satisfaction namely, work characteristic,
work progress, and colleagues significantly correlated with
organization core value in aspect of perception in choice of work at
0.5, 0.01, and 0.01 respectively. Also, such aspects were compatible
with income at .05 which indicated the low level of correlation, mid
low correlation respectively at the same direction, same direction,
opposite direction, and same direction, correspondingly.
Abstract: In this research, the authors analyze network stability
using agent-based simulation. Firstly, the authors focus on analyzing
large networks (eight agents) by connecting different two stable small
social networks (A small stable network is consisted on four agents.).
Secondly, the authors analyze the network (eight agents) shape which
is added one agent to a stable network (seven agents). Thirdly, the
authors analyze interpersonal comparison of utility. The “star-network
"was not found on the result of interaction among stable two small
networks. On the other hand, “decentralized network" was formed
from several combination. In case of added one agent to a stable
network (seven agents), if the value of “c"(maintenance cost of per
a link) was larger, the number of patterns of stable network was
also larger. In this case, the authors identified the characteristics of a
large stable network. The authors discovered the cases of decreasing
personal utility under condition increasing total utility.
Abstract: In the normal operation conditions of a pico satellite,
conventional Unscented Kalman Filter (UKF) gives sufficiently good
estimation results. However, if the measurements are not reliable
because of any kind of malfunction in the estimation system, UKF
gives inaccurate results and diverges by time. This study, introduces
Robust Unscented Kalman Filter (RUKF) algorithms with the filter
gain correction for the case of measurement malfunctions. By the use
of defined variables named as measurement noise scale factor, the
faulty measurements are taken into the consideration with a small
weight and the estimations are corrected without affecting the
characteristic of the accurate ones. Two different RUKF algorithms,
one with single scale factor and one with multiple scale factors, are
proposed and applied for the attitude estimation process of a pico
satellite. The results of these algorithms are compared for different
types of measurement faults in different estimation scenarios and
recommendations about their applications are given.
Abstract: Bicycle usage for exercise, recreation, and commuting
to work in Australia shows that pedal cycling is the fourth most
popular activity with 10.6% increase in participants between 2001
and 2007. As with other means of transport, accident and injury
becomes common although mandatory bicycle helmet wearing has
been introduced. The research aims to develop a face surrogate made
of sandwich of rigid foam and rubber sheets to represent human
facial bone under blunt impact. The facial surrogate will serve as an
important test device for further development of facial-impact
protection for cyclist. A test procedure was developed to simulate the
energy of impact and record data to evaluate the effect of impact on
facial bones. Drop tests were performed to establish a suitable
combination of materials. It was found that the sandwich structure of
rigid extruded-polystyrene foam (density of 40 kg/m3 with a pattern
of 6-mm-holes), Neoprene rubber sponge, and Abrasaflex rubber
backing, had impact characteristics comparable to that of human
facial bone. In particular, the foam thickness of 30 mm and 25 mm
was found suitable to represent human zygoma (cheekbone) and
maxilla (upper-jaw bone), respectively.
Abstract: The mixing of pollutions and sediments in near shore regions of natural water bodies depends heavily on the characteristics such as the strength and frequency of flow instability. In the present paper, the instability of natural convection induced by absorption of solar radiation in littoral regions is considered. Spectral analysis is conducted on the quasi-steady state flow to reveal the power and frequency modes of the instability at various positions. Results indicate that the power of instability, the number of frequency modes, the prominence of higher frequency modes, and the highest frequency mode increase with the offshore distance and/or Rayleigh number. Harmonic modes are present at relatively low Rayleigh numbers. For a given offshore distance, the position with the strongest power of instability is located adjacent to the sloping bottom while the frequency modes are the same over the local depth. As the Rayleigh number increases, the unstable region extends toward the shore.
Abstract: The present paper develops and validates a numerical procedure for the calculation of turbulent combustive flow in converging and diverging ducts and throuh simulation of the heat transfer processes, the amount of production and spread of Nox pollutant has been measured. A marching integration solution procedure employing the TDMA is used to solve the discretized equations. The turbulence model is the Prandtl Mixing Length method. Modeling the combustion process is done by the use of Arrhenius and Eddy Dissipation method. Thermal mechanism has been utilized for modeling the process of forming the nitrogen oxides. Finite difference method and Genmix numerical code are used for numerical solution of equations. Our results indicate the important influence of the limiting diverging angle of diffuser on the coefficient of recovering of pressure. Moreover, due to the intense dependence of Nox pollutant to the maximum temperature in the domain with this feature, the Nox pollutant amount is also in maximum level.
Abstract: Organizational structure of the Turkish state
universities is a form of bureaucracy, a high efficient system in
rational and formal control. According to the dimensional approach
bureaucracy can occur in an organization in a degree, as some
bureaucracy characteristics can be stronger than others. In addition,
the units of an organization due to their different specific
characteristic properties can perceive the bureaucracy differently. In
the study, Hall-s Organizational Inventory, which was developed for
evaluating the degree of bureaucratization from the dimensional
perspective, is used to find out if there is a difference in the
perception of the bureaucracy between the academicians working in
three different departments and two faculties in the same university.
Abstract: Median filters with larger windows offer greater smoothing and are more robust than the median filters of smaller windows. However, the larger median smoothers (the median filters with the larger windows) fail to track low order polynomial trends in the signals. Due to this, constant regions are produced at the signal corners, leading to the loss of fine details. In this paper, an algorithm, which combines the ability of the 3-point median smoother in preserving the low order polynomial trends and the superior noise filtering characteristics of the larger median smoother, is introduced. The proposed algorithm (called the combiner algorithm in this paper) is evaluated for its performance on a test image corrupted with different types of noise and the results obtained are included.
Abstract: In this paper a new maximum power point tracking
algorithm for photovoltaic arrays is proposed. The algorithm detects
the maximum power point of the PV. The computed maximum
power is used as a reference value (set point) of the control system.
ON/OFF power controller with hysteresis band is used to control the
operation of a Buck chopper such that the PV module always
operates at its maximum power computed from the MPPT algorithm.
The major difference between the proposed algorithm and other
techniques is that the proposed algorithm is used to control directly
the power drawn from the PV.
The proposed MPPT has several advantages: simplicity, high
convergence speed, and independent on PV array characteristics. The
algorithm is tested under various operating conditions. The obtained
results have proven that the MPP is tracked even under sudden
change of irradiation level.