Abstract: Partial oxidation (POX) of light hydrocarbons (e.g.
methane) is occurred in the first part of the autothermal reformer
(ATR). The results of the detailed modeling of the reformer based on
the thermodynamic model of the POX and 1D heterogeneous
catalytic model for the fixed bed section are considered here.
According to the results, the overall performance of the ATR can be
improved by changing the important feed parameters.
Abstract: This paper reports the three-phase (gas + liquid +
hydrate) equilibrium pressure versus temperature data for a (O3 + O2 +
CO2 + H2O) system for developing the hydrate-based technology to
preserve ozone, a chemically unstable substance, for various
industrial, medical and consumer uses. These data cover the
temperature range from 272 K to 277 K, corresponding to pressures
from 1.6 MPa to 3.1 MPa, for each of the three different (O3 +
O2)-to-CO2 or O2-to-CO2 molar ratios in the gas phase, which are
approximately 4 : 6, 5 : 5, respectively. The mole fraction of ozone in
the gas phase was ~0.03 , which are the densest ozone fraction to
artificially form O3 containing hydrate ever reported in the literature.
Based on these data, the formation of hydrate containing
high-concentration ozone, as high as 1 mass %, will be expected.
Abstract: Explosive forming is one of the unconventional
techniques in which, most commonly, the water is used as the
pressure transmission medium. One of the newest methods in
explosive forming is gas detonation forming which uses a normal
shock wave derived of gas detonation, to form sheet metals. For this
purpose a detonation is developed from the reaction of H2+O2
mixture in a long cylindrical detonation tube. The detonation wave
goes through the detonation tube and acts as a blast load on the steel
blank and forms it. Experimental results are compared with a finite
element model; and the comparison of the experimental and
numerical results obtained from strain, thickness variation and
deformed geometry is carried out. Numerical and experimental
results showed approximately 75 – 90 % similarity in formability of
desired shape. Also optimum percent of gas mixture obtained when
we mix 68% H2 with 32% O2.
Abstract: This paper aims to develop a NOx emission model of
an acid gas incinerator using Nelder-Mead least squares support
vector regression (LS-SVR). Malaysia DOE is actively imposing the
Clean Air Regulation to mandate the installation of analytical
instrumentation known as Continuous Emission Monitoring System
(CEMS) to report emission level online to DOE . As a hardware
based analyzer, CEMS is expensive, maintenance intensive and often
unreliable. Therefore, software predictive technique is often
preferred and considered as a feasible alternative to replace the
CEMS for regulatory compliance. The LS-SVR model is built based
on the emissions from an acid gas incinerator that operates in a LNG
Complex. Simulated Annealing (SA) is first used to determine the
initial hyperparameters which are then further optimized based on the
performance of the model using Nelder-Mead simplex algorithm.
The LS-SVR model is shown to outperform a benchmark model
based on backpropagation neural networks (BPNN) in both training
and testing data.
Abstract: The Pulsed Compression Reactor promises to be a
compact, economical and energy efficient alternative to conventional
chemical reactors.
In this article, the production of synthesis gas using the Pulsed
Compression Reactor is investigated. This is done experimentally as
well as with simulations. The experiments are done by means of a
single shot reactor, which replicates a representative, single
reciprocation of the Pulsed Compression Reactor with great control
over the reactant composition, reactor temperature and pressure and
temperature history. Simulations are done with a relatively simple
method, which uses different models for the chemistry and
thermodynamic properties of the species in the reactor. Simulation
results show very good agreement with the experimental data, and
give great insight into the reaction processes that occur within the
cycle.
Abstract: We studied the evolution of elliptic heavy SF6
gas cylinder surrounded by air when accelerated by a planar
Mach 1.25 shock. A multiple dynamics imaging technology has
been used to obtain one image of the experimental initial
conditions and five images of the time evolution of elliptic
cylinder. We compared the width and height of the circular and
two kinds of elliptic gas cylinders, and analyzed the vortex
strength of the elliptic ones. Simulations are in very good
agreement with the experiments, but due to the different initial
gas cylinder shapes, a certain difference of the initial density
peak and distribution exists between the circular and elliptic
gas cylinders, and the latter initial state is more sensitive and
more inenarrable.
Abstract: In a world of climate change and limited fossil fuel resources, renewable energy sources are playing an increasingly important role. Due to industrializations and population growth our economy and technologies today largely depend upon natural resources, which are not replaceable. Approximately 90% of our energy consumption comes from fossil fuels (viz. coal, oil and natural gas). The irony is that these resources are depleting. Also, the huge consumption of fossil fuels has caused visible damage to the environment in various forms viz. global warming, acid rains etc.
Abstract: There have been widespread applications of fluidized beds in industries which are related to the combination of gas-solid particles during the last decade. For instance, in order to crack the catalyses in petrochemical industries or as a drier in food industries. High capacity of fluidized bed in heat and mass transfer has made this device very popular. In order to achieve a higher efficiency of fluidized beds, a particular attention has been paid to beds with pulsating air flow. In this paper, a fluidized bed device with pulsating flow has been designed and constructed. Size of particles have been used during the test are in the range of 40 to 100μm. The purpose of this experimental test is to investigate the air flow regime, observe the particles- movement and measure the pressure loss along the bed. The effects of pulsation can be evaluated by comparing the results for both continuous and pulsating flow. Results of both situations are compared for various gas speeds. Moreover the above experiment is numerically simulated by using Fluent software and its numerical results are compared with the experimental results.
Abstract: Recently electric vehicles are becoming popular as an
alternative of conventional fossil fuel vehicles. Conventional Internal
Combustion Engine (ICE) vehicle uses fossil fuel which contributing
a major part of overall carbon emission in the environment. Carbon
and other green house gas emission are responsible for global
warming and resulting climate change. It becomes vital to evaluate
performance of vehicle based on emission. In this paper an effort has
been made to depict the picture of emission caused by vehicle and
scenario of Australia has taken into account. Effort has been made to
compare the fossil based vehicle with electric vehicle in phases. The
study also evaluates advancement in electric vehicle technology,
required infrastructure for sustainability and future scope of
developments. This paper also includes the evaluation of electric
vehicle concept for pollution control and sustainable transport
systems in future. This study can be a benchmark for development of
electric vehicle as low carbon emission alternative for the cities of
tomorrow.
Abstract: Rarefied gas flows are often occurred in micro electro
mechanical systems and classical CFD could not precisely anticipate
the flow and thermal behavior due to the high Knudsen number.
Therefore, the heat transfer and the fluid dynamics characteristics of
rarefied gas flows in both a two-dimensional simple microchannel
and geometry similar to single Knudsen compressor have been
investigated with a goal of increasing performance of a actual
Knudsen compressor by using a particle simulation method. Thermal
transpiration and thermal creep, which are rarefied gas dynamic
phenomena, that cause movement of the flow from less to higher
temperature is generated by using two different longitude temperature
gradients (Linear, Step) along the walls of the flow microchannel. In
this study the influence of amount of temperature gradient and
governing pressure in various Knudsen numbers and length-to-height
ratios have been examined.
Abstract: Long Term Evolution (LTE) is a 4G wireless
broadband technology developed by the Third Generation
Partnership Project (3GPP) release 8, and it's represent the
competitiveness of Universal Mobile Telecommunications System
(UMTS) for the next 10 years and beyond. The concepts for LTE
systems have been introduced in 3GPP release 8, with objective of
high-data-rate, low-latency and packet-optimized radio access
technology. In this paper, performance of different TCP variants
during LTE network investigated. The performance of TCP over
LTE is affected mostly by the links of the wired network and total
bandwidth available at the serving base station. This paper describes
an NS-2 based simulation analysis of TCP-Vegas, TCP-Tahoe, TCPReno,
TCP-Newreno, TCP-SACK, and TCP-FACK, with full
modeling of all traffics of LTE system. The Evaluation of the
network performance with all TCP variants is mainly based on
throughput, average delay and lost packet. The analysis of TCP
performance over LTE ensures that all TCP's have a similar
throughput and the best performance return to TCP-Vegas than other
variants.
Abstract: Perth will run out of available sustainable natural
water resources by 2015 if nothing is done to slow usage rates,
according to a Western Australian study [1]. Alternative water
technology options need to be considered for the long-term
guaranteed supply of water for agricultural, commercial, domestic
and industrial purposes. Seawater is an alternative source of water for
human consumption, because seawater can be desalinated and
supplied in large quantities to a very high quality.
While seawater desalination is a promising option, the technology
requires a large amount of energy which is typically generated from
fossil fuels. The combustion of fossil fuels emits greenhouse gases
(GHG) and, is implicated in climate change. In addition to
environmental emissions from electricity generation for desalination,
greenhouse gases are emitted in the production of chemicals and
membranes for water treatment. Since Australia is a signatory to the
Kyoto Protocol, it is important to quantify greenhouse gas emissions
from desalinated water production.
A life cycle assessment (LCA) has been carried out to determine
the greenhouse gas emissions from the production of 1 gigalitre (GL)
of water from the new plant. In this LCA analysis, a new desalination
plant that will be installed in Bunbury, Western Australia, and known
as Southern Seawater Desalinization Plant (SSDP), was taken as a
case study. The system boundary of the LCA mainly consists of three
stages: seawater extraction, treatment and delivery. The analysis
found that the equivalent of 3,890 tonnes of CO2 could be emitted
from the production of 1 GL of desalinated water. This LCA analysis
has also identified that the reverse osmosis process would cause the
most significant greenhouse emissions as a result of the electricity
used if this is generated from fossil fuels
Abstract: Prediction of viscosity of natural gas is an important parameter in the energy industries such as natural gas storage and transportation. In this study viscosity of different compositions of natural gas is modeled by using an artificial neural network (ANN) based on back-propagation method. A reliable database including more than 3841 experimental data of viscosity for testing and training of ANN is used. The designed neural network can predict the natural gas viscosity using pseudo-reduced pressure and pseudo-reduced temperature with AARD% of 0.221. The accuracy of designed ANN has been compared to other published empirical models. The comparison indicates that the proposed method can provide accurate results.
Abstract: Carbon disulfide is widely used for the production of
viscose rayon, rubber, and other organic materials and it is a
feedstock for the synthesis of sulfuric acid. The objective of this
paper is to analyze possibilities for efficient production of CS2 from
sour natural gas reformation (H2SMR) (2H2S+CH4 =CS2 +4H2) .
Also, the effect of H2S to CH4 feed ratio and reaction temperature on
carbon disulfide production is investigated numerically in a
reforming reactor. The chemical reaction model is based on an
assumed Probability Density Function (PDF) parameterized by the
mean and variance of mixture fraction and β-PDF shape. The results
show that the major factors influencing CS2 production are reactor
temperature. The yield of carbon disulfide increases with increasing
H2S to CH4 feed gas ratio (H2S/CH4≤4). Also the yield of C(s)
increases with increasing temperature until the temperature reaches
to 1000°K, and then due to increase of CS2 production and
consumption of C(s), yield of C(s) drops with further increase in the
temperature. The predicted CH4 and H2S conversion and yield of
carbon disulfide are in good agreement with result of Huang and TRaissi.
Abstract: The utilize of renewable energy sources becomes
more crucial and fascinatingly, wider application of renewable
energy devices at domestic, commercial and industrial levels is not
only affect to stronger awareness but also significantly installed
capacities. Moreover, biomass principally is in form of woods and
converts to be energy for using by humans for a long time.
Gasification is a process of conversion of solid carbonaceous fuel
into combustible gas by partial combustion. Many gasified models
have various operating conditions because the parameters kept in
each model are differentiated. This study applied the experimental
data including three inputs variables including biomass consumption;
temperature at combustion zone and ash discharge rate and gas flow
rate as only one output variable. In this paper, response surface
methods were applied for identification of the gasified system
equation suitable for experimental data. The result showed that linear
model gave superlative results.
Abstract: Fischer-Tropsch synthesis is one of the most
important catalytic reactions that convert the synthetic gas to light
and heavy hydrocarbons. One of the main issues is selecting the type
of reactor. The slurry bubble reactor is suitable choice for Fischer-
Tropsch synthesis because of its good qualification to transfer heat
and mass, high durability of catalyst, low cost maintenance and
repair. The more common catalysts for Fischer-Tropsch synthesis are
Iron-based and Cobalt-based catalysts, the advantage of these
catalysts on each other depends on which type of hydrocarbons we
desire to produce. In this study, Fischer-Tropsch synthesis is modeled
with Iron and Cobalt catalysts in a slurry bubble reactor considering
mass and momentum balance and the hydrodynamic relations effect
on the reactor behavior. Profiles of reactant conversion and reactant
concentration in gas and liquid phases were determined as the
functions of residence time in the reactor. The effects of temperature,
pressure, liquid velocity, reactor diameter, catalyst diameter, gasliquid
and liquid-solid mass transfer coefficients and kinetic
coefficients on the reactant conversion have been studied. With 5%
increase of liquid velocity (with Iron catalyst), H2 conversions
increase about 6% and CO conversion increase about 4%, With 8%
increase of liquid velocity (with Cobalt catalyst), H2 conversions
increase about 26% and CO conversion increase about 4%. With
20% increase of gas-liquid mass transfer coefficient (with Iron
catalyst), H2 conversions increase about 12% and CO conversion
increase about 10% and with Cobalt catalyst H2 conversions increase
about 10% and CO conversion increase about 6%. Results show that
the process is sensitive to gas-liquid mass transfer coefficient and
optimum condition operation occurs in maximum possible liquid
velocity. This velocity must be more than minimum fluidization
velocity and less than terminal velocity in such a way that avoid
catalysts particles from leaving the fluidized bed.
Abstract: The objective of this research is to calculate the
optimal inventory lot-sizing for each supplier and minimize the total
inventory cost which includes joint purchase cost of the products,
transaction cost for the suppliers, and holding cost for remaining
inventory. Genetic algorithms (GAs) are applied to the multi-product
and multi-period inventory lot-sizing problems with supplier
selection under storage space. Also a maximum storage space for the
decision maker in each period is considered. The decision maker
needs to determine what products to order in what quantities with
which suppliers in which periods. It is assumed that demand of
multiple products is known over a planning horizon. The problem is
formulated as a mixed integer programming and is solved with the
GAs. The detailed computation results are presented.
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: Two-dimensional Direct Numerical Simulation (DNS)
of high Schmidt number mass transfer in a convective flow environment
(Rayleigh-B'enard) is carried out and results are compared to
experimental data. A fourth-order accurate WENO-scheme has been
used for scalar transport in order to aim for a high accuracy in areas
of high concentration gradients. It was found that the typical spatial
distance between downward plumes of cold high concentration water
and the eddy size are in good agreement with experiments using a
combined PIV-LIF technique for simultaneous and spatially synoptic
measurements of 2D velocity and concentration fields.
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.