Abstract: This study presents a simulation model for converting coal to methanol, based on gasification technology with the commercial chemical process simulator, Pro/II® V8.1.1. The methanol plant consists of air separation unit (ASU), gasification unit, gas clean-up unit, and methanol synthetic unit. The clean syngas is produced with the first three operating units, and the model has been verified with the reference data from United States Environment Protection Agency. The liquid phase methanol (LPMEOHTM) process is adopted in the methanol synthetic unit. Clean syngas goes through gas handing section to reach the reaction requirement, reactor loop/catalyst to generate methanol, and methanol distillation to get desired purity over 99.9 wt%. The ratio of the total energy combined with methanol and dimethyl ether to that of feed coal is 78.5% (gross efficiency). The net efficiency is 64.2% with the internal power consumption taken into account, based on the assumption that the efficiency of electricity generation is 40%.
Abstract: In this study, we sought to investigate the mercury
removal efficiency of manganese oxides from natural gas. The
fundamental studies on mercury removal with manganese oxides
sorbents were carried out in a laboratory scale fixed bed reactor at 30
°C with a mixture of methane (20%) and nitrogen gas laden with 4.8
ppb of elemental mercury. Manganese oxides with varying surface
area and crystalline phase were prepared by conventional precipitation
method in this study. The effects of surface area, crystallinity and
other metal oxides on mercury removal efficiency were investigated.
Effect of Ag impregnation on mercury removal efficiency was also
investigated. Ag supported on metal oxide such titania and zirconia as
reference materials were also used in this study for comparison. The
characteristics of mercury removal reaction with manganese oxide
was investigated using a temperature programmed desorption (TPD)
technique.
Manganese oxides showed very high Hg removal activity (about
73-93% Hg removal) for first time use. Surface area of the manganese
oxide samples decreased after heat-treatment and resulted in complete
loss of Hg removal ability for repeated use after Hg desorption in the
case of amorphous MnO2, and 75% loss of the initial Hg removal
activity for the crystalline MnO2. Mercury desorption efficiency of
crystalline MnO2 was very low (37%) for first time use and high (98%)
after second time use. Residual potassium content in MnO2 may have
some effect on the thermal stability of the adsorbed Hg species.
Desorption of Hg from manganese oxides occurs at much higher
temperatures (with a peak at 400 °C) than Ag/TiO2 or Ag/ZrO2.
Mercury may be captured on manganese oxides in the form of mercury
manganese oxide.
Abstract: Understanding patient factors related to physical activity behavior is important in the management of Type 2 Diabetes. This study applied the Theory of Planned Behavior model to understand physical activity behavior among sampled Type 2 diabetics in Kenya. The study was conducted within the diabetic clinic at Kisii Level 5 Hospital and adopted sequential mixed methods design beginning with qualitative phase and ending with quantitative phase. Qualitative data was analyzed using grounded theory analysis method. Structural equation modeling using maximum likelihood was used to analyze quantitative data. The common fit indices revealed that the theory of planned behavior fitted the data acceptably well among the Type 2 diabetes and within physical activity behavior {¤ç2 = 213, df = 84, n=230, p = .061, ¤ç2/df = 2.53; TLI = .97; CFI =.96; RMSEA (90CI) = .073(.029, .08)}. This theory proved to be useful in understanding physical activity behavior among Type 2 diabetics.
Abstract: Bubble columns have a variety of applications in
absorption, bio-reactions, catalytic slurry reactions, and coal
liquefaction; because they are simple to operate, provide good heat
and mass transfer, having less operational cost. The use of
Computational Fluid Dynamics (CFD) for bubble column becomes
important, since it can describe the fluid hydrodynamics on both local
and global scale. Euler- Euler two-phase fluid model has been used to
simulate two-phase (air and water) transient up-flow in bubble
column (15cm diameter) using FLUENT6.3. These simulations and
experiments were operated over a range of superficial gas velocities
in the bubbly flow and churn turbulent regime (1 to16 cm/s) at
ambient conditions. Liquid velocity was varied from 0 to 16cm/s. The
turbulence in the liquid phase is described using the standard k-ε
model. The interactions between the two phases are described
through drag coefficient formulations (Schiller Neumann). The
objectives are to validate CFD simulations with experimental data,
and to obtain grid-independent numerical solutions. Quantitatively
good agreements are obtained between experimental data for hold-up
and simulation values. Axial liquid velocity profiles and gas holdup
profiles were also obtained for the simulation.
Abstract: This paper discusses the approach of real-time
controlling of the energy management system using the data
acquisition tool of LabVIEW. The main idea of this inspiration was
to interface the Station (PC) with the system and publish the data on
internet using LabVIEW. In this venture, controlling and switching of
3 phase AC loads are effectively and efficiently done. The phases are
also sensed through devices. In case of any failure the attached
generator starts functioning automatically. The computer sends
command to the system and system respond to the request. The
modern feature is to access and control the system world-wide using
world wide web (internet). This controlling can be done at any time
from anywhere to effectively use the energy especially in developing
countries where energy management is a big problem. In this system
totally integrated devices are used to operate via remote location.
Abstract: In this research, a systematic investigation was carried out to determine the optimum conditions of HDS reactor. Moreover, a suitable model was developed for a rigorous RTO (real time optimization) loop of HDS (Hydro desulfurization) process. A systematic experimental series was designed based on CCD (Central Composite design) and carried out in the related pilot plant to tune the develop model. The designed variables in the experiments were Temperature, LHSV and pressure. However, the hydrogen over fresh feed ratio was remained constant. The ranges of these variables were respectively equal to 320-380ºC, 1- 21/hr and 50-55 bar. a power law kinetic model was also developed for our further research in the future .The rate order and activation energy , power of reactant concentration and frequency factor of this model was respectively equal to 1.4, 92.66 kJ/mol and k0=2.7*109 .
Abstract: Mining frequent tree patterns have many useful
applications in XML mining, bioinformatics, network routing, etc.
Most of the frequent subtree mining algorithms (i.e. FREQT,
TreeMiner and CMTreeMiner) use anti-monotone property in the
phase of candidate subtree generation. However, none of these
algorithms have verified the correctness of this property in tree
structured data. In this research it is shown that anti-monotonicity
does not generally hold, when using weighed support in tree pattern
discovery. As a result, tree mining algorithms that are based on this
property would probably miss some of the valid frequent subtree
patterns in a collection of trees. In this paper, we investigate the
correctness of anti-monotone property for the problem of weighted
frequent subtree mining. In addition we propose W3-Miner, a new
algorithm for full extraction of frequent subtrees. The experimental
results confirm that W3-Miner finds some frequent subtrees that the
previously proposed algorithms are not able to discover.
Abstract: In this paper, the melting of a semi-infinite body as a
result of a moving laser beam has been studied. Because the Fourier
heat transfer equation at short times and large dimensions does not
have sufficient accuracy; a non-Fourier form of heat transfer
equation has been used. Due to the fact that the beam is moving in x
direction, the temperature distribution and the melting pool shape are
not asymmetric. As a result, the problem is a transient threedimensional
problem. Therefore, thermophysical properties such as
heat conductivity coefficient, density and heat capacity are functions
of temperature and material states. The enthalpy technique, used for
the solution of phase change problems, has been used in an explicit
finite volume form for the hyperbolic heat transfer equation. This
technique has been used to calculate the transient temperature
distribution in the semi-infinite body and the growth rate of the melt
pool. In order to validate the numerical results, comparisons were
made with experimental data. Finally, the results of this paper were
compared with similar problem that has used the Fourier theory. The
comparison shows the influence of infinite speed of heat propagation
in Fourier theory on the temperature distribution and the melt pool
size.
Abstract: Diagnostic and detection of the arterial stiffness is
very important; which gives indication of the associated increased risk of cardiovascular diseases. To make a cheap and easy method for general screening technique to avoid the future cardiovascular
complexes , due to the rising of the arterial stiffness ; a proposed algorithm depending on photoplethysmogram to be used. The
photoplethysmograph signals would be processed in MATLAB. The
signal will be filtered, baseline wandering removed, peaks and
valleys detected and normalization of the signals should be achieved
.The area under the catacrotic phase of the photoplethysmogram
pulse curve is calculated using trapezoidal algorithm ; then will used
in cooperation with other parameters such as age, height, blood
pressure in neural network for arterial stiffness detection. The Neural
network were implemented with sensitivity of 80%, accuracy 85%
and specificity of 90% were got from the patients data. It is
concluded that neural network can detect the arterial STIFFNESS
depending on risk factor parameters.
Abstract: This paper discusses a systematic design of a Σ-Δ fractional-N Phase-Locked Loop based on HDL behavioral modeling. The proposed design consists in describing the mixed behavior of this PLL architecture starting from the specifications of each building block. The HDL models of critical PLL blocks have been described in VHDL-AMS to predict the different specifications of the PLL. The effect of different noise sources has been efficiently introduced to study the PLL system performances. The obtained results are compared with transistor-level simulations to validate the effectiveness of the proposed models for wireless applications in the frequency range around 2.45 GHz.
Abstract: Semnan is a city in semnan province, northern Iran
with a population estimated at 119,778 inhabitants. It is the
provincial capital of semnan province. Iran is a developing country
and construction is a basic factor of developing too. Hence, Semnan
city needs to a special programming for construction of buildings,
structures and infrastructures. Semnan municipality tries to begin this
program. In addition to, city has some historical monuments which
can be interesting for tourists. Hence, Semnan inhabitants can benefit
from tourist industry. Optimization of Energy in construction
industry is another activity of this municipality and the inhabitants
who execute these regulations receive some discounts. Many parts of
Iran such as semnan are located in highly seismic zones and
structures must be constructed safe e.g., according to recent seismic
codes. In this paper opportunities of IT in construction industry of
Iran are investigated in three categories. Pre-construction phase,
construction phase and earthquake disaster mitigation are studied.
Studies show that information technology can be used in these items
for reducing the losses and increasing the benefits. Both government
and private sectors must contribute to this strategic project for
obtaining the best result.
Abstract: The effect of muscle loss due to transfemoral
amputation, on energy expenditure of hip joint and individual
residual muscles was simulated. During swing phase of gait, with
each muscle as an ideal force generator, the lower extremity was
modeled as a two-degree of freedom linkage, for which hip and knee
were joints. According to results, muscle loss will not lead to higher
energy expenditure of hip joint, as long as other parameters of limb
remain unaffected. This finding maybe due to the role of biarticular
muscles in hip and knee joints motion. Moreover, if hip flexors are
removed from the residual limb, residual flexors, and if hip extensors
are removed, residual extensors will do more work. In line with the
common practice in transfemoral amputation, this result demonstrates
during transfemoral amputation, it is important to maintain the length
of residual limb as much as possible.
Abstract: Theoptimal extraction condition of dried Phaseolus
vulgaris powderwas studied. The three independent variables are raw
material concentration, shaking and centrifugaltime. The dependent
variables are both yield percentage of crude extract and alphaamylase
enzyme inhibition activity. The experimental design was
based on box-behnkendesign. Highest yield percentage of crude
extract could get from extraction condition at concentration of 1, 0,1,
concentration of 0.15 M ,extraction time for 2hour, and
separationtime for60 min. Moreover, the crude extract with highest
alpha-amylase enzyme inhibition activityoccurred by extraction
condition at concentration of 0.10 M, extraction time for 2 min, and
separation time for 45 min
Abstract: The main objective of this paper is to investigate the
enhancement of power system stability via coordinated tuning of
Power System Stabilizers (PSSs) in a multi-machine power system.
The design problem of the proposed controllers is formulated as an
optimization problem. Chaotic catfish particle swarm optimization
(C-Catfish PSO) algorithm is used to minimize the ITAE objective
function. The proposed algorithm is evaluated on a two-area, 4-
machines system. The robustness of the proposed algorithm is
verified on this system under different operating conditions and
applying a three-phase fault. The nonlinear time-domain simulation
results and some performance indices show the effectiveness of the
proposed controller in damping power system oscillations and this
novel optimization algorithm is compared with particle swarm
optimization (PSO).
Abstract: The alumosilicate ceramics with mullite crystalline phase are used in various branches of science and technique. The mullite refractory ceramics with high porosity serve as a heat insulator and as a constructional materials [1], [2]. The purpose of the work was to sinter high porosity ceramic and to increase the quantity of mullite phase in this mullite, mullite-corundum ceramics. Two types of compositions were prepared at during the experiment. The first type is compositions with commercial alumina and silica oxides. The second type is from mixing these oxides with 10, 20 and 30 wt.%. of kaolin. In all samples the Al2O3 and SiO2 were in 2.57:1 ratio, because that was conformed to mullite stechiometric compositions (3Al2O3.2SiO2). The types of alumina oxides were α-Al2O3 (d50=4µm) and γ-Al2O3 (d50=80µm). Ratios of α-: γ-Al2O3 were (1:1) or (1:3). The porous materials were prepared by slip casting of suspension of raw materials. The aluminium paste (0.18 wt.%) was used as a pore former. Water content in the suspensions was 26-47 wt.%. Pore formation occurred as a result of hydrogen formation in chemical reaction between aluminium paste and water [2]. The samples were sintered at the temperature of 1650°C and 1750°C for one hour. The increasing amount of kaolin, α-: γ-Al2O3 at the ratio (1:3) and sintering at the highest temperature raised the quantity of mullite phase. The mullite phase began to dominate over the corundum phase.
Abstract: Phase locked loops in 10 Gb/s and faster data links are
low phase noise devices. Characterization of their phase jitter
transfer functions is difficult because the intrinsic noise of the PLLs
is comparable to the phase noise of the reference clock signal. The
problem is solved by using a linear model to account for the intrinsic
noise. This study also introduces a novel technique for measuring the
transfer function. It involves the use of the reference clock as a
source of wideband excitation, in contrast to the commonly used
sinusoidal excitations at discrete frequencies. The data reported here
include the intrinsic noise of a PLL for 10 Gb/s links and the jitter
transfer function of a PLL for 12.8 Gb/s links. The measured transfer
function suggests that the PLL responded like a second order linear
system to a low noise reference clock.
Abstract: Due to its capability to resist jamming signals, chirp
spread spectrum (CSS) technique has attracted much attention in
the area of wireless communications. However, there has been little
rigorous analysis for the performance of the CSS communication
system in jamming environments. In this paper, we present analytic
results on the performance of a CSS system by deriving symbol
error rate (SER) expressions for a CSS M-ary phase shift keying
(MPSK) system in the presence of broadband and tone jamming
signals, respectively. The numerical results show that the empirical
SER closely agrees with the analytic result.
Abstract: In the hardening energy context, the transport sector
which constitutes a large worldwide energy demand has to be
improving for decrease energy demand and global warming impacts.
In a controversial situation where subsists an increasing demand for
long-distance and high-speed travels, high-speed trains offer many
advantages, as consuming significantly less energy than road or air
transports.
At the project phase of new rail infrastructures, it is nowadays
important to characterize accurately the energy that will be induced
by its operation phase, in addition to other more classical criteria as
construction costs and travel time.
Current literature consumption models used to estimate railways
operation phase are obsolete or not enough accurate for taking into
account the newest train or railways technologies.
In this paper, an updated model of consumption for high-speed is
proposed, based on experimental data obtained from full-scale tests
performed on a new high-speed line. The assessment of the model
is achieved by identifying train parameters and measured power
consumptions for more than one hundred train routes. Perspectives
are then discussed to use this updated model for accurately assess
the energy impact of future railway infrastructures.
Abstract: In the current work, a numerical parametric study was
performed in order to model the fluid mechanics in the riser of a
bubbling fluidized bed (BFB). The gas-solid flow was simulated by
mean of a multi-fluid Eulerian model incorporating the kinetic theory
for solid particles. The bubbling fluidized bed was simulated two
dimensionally by mean of a Computational Fluid Dynamic (CFD)
commercial software package, Fluent. The effects of using different
inter-phase drag function (the drag model of Gidaspow, Syamlal and
O-Brien and the EMMS drag model) on the model predictions were
evaluated and compared. The results showed that the drag models of
Gidaspow and Syamlal and O-Brien overestimated the drag force for
the FCC particles and predicted a greater bed expansion in
comparison to the EMMS drag model.
Abstract: Downward turbulent bubbly flows in pipes were
modeled using computational fluid dynamics tools. The
Hydrodynamics, phase distribution and turbulent structure of twophase
air-water flow in a 57.15 mm diameter and 3.06 m length
vertical pipe was modeled by using the 3-D Eulerian-Eulerian
multiphase flow approach. Void fraction, liquid velocity and
turbulent fluctuations profiles were calculated and compared against
experimental data. CFD results are in good agreement with
experimental data.