Abstract: Drop-in of R-22 alternatives in refrigeration and air conditioning systems requires a redesign of system components to improve system performance and reliability with the alternative refrigerants. The present paper aims at design adiabatic capillary tubes for R-22 alternatives such as R-417A, R-422D and R-438A. A theoretical model has been developed and validated with the available experimental data from literature for R-22 over a wide range of both operating and geometrical parameters. Predicted lengths of adiabatic capillary tube are compared with the lengths of the capillary tube needed under similar experimental conditions and majority of predictions are found to be within 4.4% of the experimental data. Hence, the model has been applied for R-417A, R- 422D and R-438A and capillary tube selection charts and correlations have been computed. Finally a comparison between the selected refrigerants and R-22 has been introduced and the results showed that R-438A is the closest one to R-22.
Abstract: To increase precision and reliability of automatic control systems, we have to take into account of random factors affecting the control system. Thus, operational matrix technique is used for statistical analysis of first order plus time delay system with uniform random parameter. Examples with deterministic and stochastic disturbance are considered to demonstrate the validity of the method. Comparison with Monte Carlo method is made to show the computational effectiveness of the method.
Abstract: The article presents the whole model of IS/IT
architecture exception governance. As first, the assumptions of
presented model are set. As next, there is defined a generic
governance model that serves as a basis for the architecture exception
governance. The architecture exception definition and its attributes
follow. The model respects well known approaches to the area that
are described in the text, but it adopts higher granularity in
description and expands the process view with all the next necessary
governance components as roles, principles and policies, tools to
enable the implementation of the model into organizations. The
architecture exception process is decomposed into a set of processes
related to the architecture exception lifecycle consisting of set of
phases and architecture exception states. Finally, there is information
about my future research related to this area.
Abstract: Due to heavy energy constraints in WSNs clustering is
an efficient way to manage the energy in sensors. There are many
methods already proposed in the area of clustering and research is
still going on to make clustering more energy efficient. In our paper
we are proposing a minimum spanning tree based clustering using
divide and conquer approach. The MST based clustering was first
proposed in 1970’s for large databases. Here we are taking divide and
conquer approach and implementing it for wireless sensor networks
with the constraints attached to the sensor networks. This Divide and
conquer approach is implemented in a way that we don’t have to
construct the whole MST before clustering but we just find the edge
which will be the part of the MST to a corresponding graph and
divide the graph in clusters there itself if that edge from the graph can
be removed judging on certain constraints and hence saving lot of
computation.
Abstract: Simultaneous Saccharification and Fermentation (SSF) of sugarcane bagasse by cellulase and Pachysolen tannophilus MTCC *1077 were investigated in the present study. Important process variables for ethanol production form pretreated bagasse were optimized using Response Surface Methodology (RSM) based on central composite design (CCD) experiments. A 23 five level CCD experiments with central and axial points was used to develop a statistical model for the optimization of process variables such as incubation temperature (25–45°) X1, pH (5.0–7.0) X2 and fermentation time (24–120 h) X3. Data obtained from RSM on ethanol production were subjected to the analysis of variance (ANOVA) and analyzed using a second order polynomial equation and contour plots were used to study the interactions among three relevant variables of the fermentation process. The fermentation experiments were carried out using an online monitored modular fermenter 2L capacity. The processing parameters setup for reaching a maximum response for ethanol production was obtained when applying the optimum values for temperature (32°C), pH (5.6) and fermentation time (110 h). Maximum ethanol concentration (3.36 g/l) was obtained from 50 g/l pretreated sugarcane bagasse at the optimized process conditions in aerobic batch fermentation. Kinetic models such as Monod, Modified Logistic model, Modified Logistic incorporated Leudeking – Piret model and Modified Logistic incorporated Modified Leudeking – Piret model have been evaluated and the constants were predicted.
Abstract: This paper presents a numerical approach for the static
and dynamic analysis of hydrodynamic radial journal bearings. In the
first part, the effect of shaft and housing deformability on pressure
distribution within oil film is investigated. An iterative algorithm that
couples Reynolds equation with a plane finite elements (FE)
structural model is solved. Viscosity-to-pressure dependency (Vogel-
Barus equation) is also included. The deformed lubrication gap and
the overall stress state are obtained. Numerical results are presented
with reference to a typical journal bearing configuration at two
different inlet oil temperatures. Obtained results show the great
influence of bearing components structural deformation on oil
pressure distribution, compared with results for ideally rigid
components. In the second part, a numerical approach based on
perturbation method is used to compute stiffness and damping
matrices, which characterize the journal bearing dynamic behavior.
Abstract: In this paper, a study on the applications of the
optimization and regression techniques for optimal calculation of
partial ratios of helical gearboxes with second-step double gear-sets
for minimal cross section dimension is introduced. From the condition
of the moment equilibrium of a mechanic system including three gear
units and their regular resistance condition, models for calculation of
the partial ratios of helical gearboxes with second-step double
gear-sets were given. Especially, by regression analysis, explicit
models for calculation of the partial ratios are introduced. These
models allow determining the partial ratios accurately and simply.
Abstract: Humic acids (HAs) have been shown to activate some
ion uptakes along with stimulating the lateral roots at effective
concentration of micronutrients. However, the effects of HA on ion
adsorption by plant roots are not easily explainable due to the
varieties of HAs that differ from origins. Therefore, this study was
aimed to investigate the effect of various concentrations of HA
obtained from the compost derived from mix manures and some
agricultural wastes on the growth of eggplant seedlings (Solanum
melongena L. cv. Chao Praya) in tissue cultures at low nutrient level.
Egg plant seeds were surfaced sterilized and germinated in ½
Murashige and Skoog medium (MS) without HA added or in ¼ MS
supplemented with 0, 25, 50, 75 and 100 ppm of HAs. Then, they
were cultured for 4 weeks under the controlled environment. The
results showed that seedlings grown on ¼MS supplemented with
HAs at the concentration of 25 and 50 ppm had the average plant
heights (2.49 and 2.28 cm, respectively) higher than the other
treatments. Both treatments also significantly showed the maximum
average fresh and dry weights (p
Abstract: Bacterial cellulose, a biopolysaccharide, is produced by the bacterium, Gluconacetobacter xylinus. Static batch fermentation for bacterial cellulose production was studied in sucrose and date syrup solutions (Bx. 10%) at 28 °C using G. xylinus (PTCC, 1734). Results showed that the maximum yields of bacterial cellulose (BC) were 4.35 and 1.69 g/l00 ml for date syrup and sucrose medium after 336 hours fermentation period, respectively. Comparison of FTIR spectrum of cellulose with BC indicated appropriate coincidence which proved that the component produced by G. xylinus was cellulose. Determination of the area under X-ray diffractometry patterns demonstrated that the crystallinity amount of cellulose (83.61%) was more than that for the BC (60.73%). The scanning electron microscopy imaging of BC and cellulose were carried out in two magnifications of 1 and 6K. Results showed that the diameter ratio of BC to cellulose was approximately 1/30 which indicated more delicacy of BC fibers relative to cellulose.
Abstract: The effect of the discontinuity of the rail ends and the
presence of lower modulus insulation material at the gap to the
variations of stresses in the insulated rail joint (IRJ) is presented. A
three-dimensional wheel – rail contact model in the finite element
framework is used for the analysis. It is shown that the maximum stress
occurs in the subsurface of the railhead when the wheel contact occurs
far away from the rail end and migrates to the railhead surface as the
wheel approaches the rail end; under this condition, the interface
between the rail ends and the insulation material has suffered
significantly increased levels of stress concentration. The ratio of the
elastic modulus of the railhead and insulation material is found to alter
the levels of stress concentration. Numerical result indicates that a
higher elastic modulus insulating material can reduce the stress
concentration in the railhead but will generate higher stresses in the
insulation material, leading to earlier failure of the insulation material
Abstract: Generally flow behavior in centrifugal fan is observed
to be in a state of instability with flow separation zones on suction
surface as well as near the front shroud. Overall performance of the
diffusion process in a centrifugal fan could be enhanced by
judiciously introducing the boundary layer suction slots. With easy
accessibility of CFD as an analytical tool, an extensive numerical
whole field analysis of the effect of boundary layer suction slots in
discrete regions of suspected separation points is possible. This paper
attempts to explore the effect of boundary layer suction slots
corresponding to various geometrical locations on the impeller with
converging configurations for the slots. The analysis shows that the
converging suction slots located on the impeller blade about 25%
from the trailing edge, significantly improves the static pressure
recovery across the fan. Also it is found that Slots provided at a
radial distance of about 12% from the leading and trailing edges
marginally improve the static pressure recovery across the fan.
Abstract: In this paper three different approaches for person
verification and identification, i.e. by means of fingerprints, face and
voice recognition, are studied. Face recognition uses parts-based
representation methods and a manifold learning approach. The
assessment criterion is recognition accuracy. The techniques under
investigation are: a) Local Non-negative Matrix Factorization
(LNMF); b) Independent Components Analysis (ICA); c) NMF with
sparse constraints (NMFsc); d) Locality Preserving Projections
(Laplacianfaces). Fingerprint detection was approached by classical
minutiae (small graphical patterns) matching through image
segmentation by using a structural approach and a neural network as
decision block. As to voice / speaker recognition, melodic cepstral
and delta delta mel cepstral analysis were used as main methods, in
order to construct a supervised speaker-dependent voice recognition
system. The final decision (e.g. “accept-reject" for a verification
task) is taken by using a majority voting technique applied to the
three biometrics. The preliminary results, obtained for medium
databases of fingerprints, faces and voice recordings, indicate the
feasibility of our study and an overall recognition precision (about
92%) permitting the utilization of our system for a future complex
biometric card.
Abstract: In this paper, a frequency-variation based method has
been proposed for transistor parameter estimation in a commonemitter
transistor amplifier circuit. We design an algorithm to estimate
the transistor parameters, based on noisy measurements of the output
voltage when the input voltage is a sine wave of variable frequency
and constant amplitude. The common emitter amplifier circuit has
been modelled using the transistor Ebers-Moll equations and the
perturbation technique has been used for separating the linear and
nonlinear parts of the Ebers-Moll equations. This model of the amplifier
has been used to determine the amplitude of the output sinusoid as
a function of the frequency and the parameter vector. Then, applying
the proposed method to the frequency components, the transistor
parameters have been estimated. As compared to the conventional
time-domain least squares method, the proposed method requires
much less data storage and it results in more accurate parameter
estimation, as it exploits the information in the time and frequency
domain, simultaneously. The proposed method can be utilized for
parameter estimation of an analog device in its operating range of
frequencies, as it uses data collected from different frequencies output
signals for parameter estimation.
Abstract: Markov games are a generalization of Markov
decision process to a multi-agent setting. Two-player zero-sum
Markov game framework offers an effective platform for designing
robust controllers. This paper presents two novel controller design
algorithms that use ideas from game-theory literature to produce
reliable controllers that are able to maintain performance in presence
of noise and parameter variations. A more widely used approach for
controller design is the H∞ optimal control, which suffers from high
computational demand and at times, may be infeasible. Our approach
generates an optimal control policy for the agent (controller) via a
simple Linear Program enabling the controller to learn about the
unknown environment. The controller is facing an unknown
environment, and in our formulation this environment corresponds to
the behavior rules of the noise modeled as the opponent. Proposed
controller architectures attempt to improve controller reliability by a
gradual mixing of algorithmic approaches drawn from the game
theory literature and the Minimax-Q Markov game solution
approach, in a reinforcement-learning framework. We test the
proposed algorithms on a simulated Inverted Pendulum Swing-up
task and compare its performance against standard Q learning.
Abstract: Method of determining of moisture diffusivity on two types of autoclaved aerated concretes with different bulk density is represented in the paper. On the specimens were measured one dimensional water transport only on liquid phase. Ever evaluation was done from moisture profiles measured in specific times by capacitance moisture meter. All values from capacitance meter were recalculated to moisture content by mass. Moisture diffusivity was determined in dependence on both moisture and temperature. The experiment temperatures were set at values 55, 65, 75 and 85°C.
Abstract: The study of the interaction between humans and
computers has been emerging during the last few years. This
interaction will be more powerful if computers are able to perceive
and respond to human nonverbal communication such as emotions. In
this study, we present the image-based approach to emotion
classification through lower facial expression. We employ a set of
feature points in the lower face image according to the particular face
model used and consider their motion across each emotive expression
of images. The vector of displacements of all feature points input to
the Adaptive Support Vector Machines (A-SVMs) classifier that
classify it into seven basic emotions scheme, namely neutral, angry,
disgust, fear, happy, sad and surprise. The system was tested on the
Japanese Female Facial Expression (JAFFE) dataset of frontal view
facial expressions [7]. Our experiments on emotion classification
through lower facial expressions demonstrate the robustness of
Adaptive SVM classifier and verify the high efficiency of our
approach.
Abstract: Wireless Sensor Networks (WSNs) have attracted the attention of many researchers. This has resulted in their rapid integration in very different areas such as precision agriculture,environmental monitoring, object and event detection and military surveillance. Due to the current WSN characteristics this technology is specifically useful in industrial areas where security, reliability and autonomy are basic, such as nuclear power plants, chemical plants, and others. In this paper we present a system based on WSNs to monitor environmental conditions around and inside a nuclear power plant, specifically, radiation levels. Sensor nodes, equipped with radiation sensors, are deployed in fixed positions throughout the plant. In addition, plant staff are also equipped with mobile devices with higher capabilities than sensors such as for example PDAs able to monitor radiation levels and other conditions around them. The system enables communication between PDAs, which form a Mobile Ad-hoc Wireless Network (MANET), and allows workers to monitor remote conditions in the plant. It is particularly useful during stoppage periods for inspection or in the event of an accident to prevent risk situations.
Abstract: This paper proposes the novel model order
formulation scheme to design a discrete PID controller for higher
order linear time invariant discrete systems. Modified PSO (MPSO)
based model order formulation technique has used to obtain the
successful formulated second order system. PID controller is tuned to
meet the desired performance specification by using pole-zero
cancellation and proposed design procedures. Proposed PID
controller is attached with both higher order system and formulated
second order system. System specifications are tabulated and closed
loop response is observed for stabilization process. The proposed
method is illustrated through numerical examples from literature.
Abstract: The purpose of this study is to investigate the chemical
degradation of the organophosphorus pesticide of parathion and
carbamate insecticide of methomyl in the aqueous phase through
Fenton process. With the employment of batch Fenton process, the
degradation of the two selected pesticides at different pH, initial
concentration, humic acid concentration, and Fenton reagent dosages
was explored. The Fenton process was found effective to degrade
parathion and methomyl. The optimal dosage of Fenton reagents (i.e.,
molar concentration ratio of H2O2 to Fe2+) at pH 7 for parathion
degradation was equal to 3, which resulted in 50% removal of
parathion. Similarly, the optimal dosage for methomyl degradation
was 1, resulting in 80% removal of methomyl. This study also found
that the presence of humic substances has enhanced pesticide
degradation by Fenton process significantly. The mass spectroscopy
results showed that the hydroxyl free radical may attack the single
bonds with least energy of investigated pesticides to form smaller
molecules which is more easily to degrade either through
physio-chemical or bilolgical processes.
Abstract: In this paper, a self starting two step continuous block
hybrid formulae (CBHF) with four Off-step points is developed using
collocation and interpolation procedures. The CBHF is then used to
produce multiple numerical integrators which are of uniform order
and are assembled into a single block matrix equation. These
equations are simultaneously applied to provide the approximate
solution for the stiff ordinary differential equations. The order of
accuracy and stability of the block method is discussed and its
accuracy is established numerically.