Abstract: Natural gas is the most popular fossil fuel in the
current era and future as well. Natural gas is existed in underground
reservoirs so it may contain many of non-hydrocarbon components
for instance, hydrogen sulfide, nitrogen and water vapor. These
impurities are undesirable compounds and cause several technical
problems for example, corrosion and environment pollution.
Therefore, these impurities should be reduce or removed from natural
gas stream. Khurmala dome is located in southwest Erbil-Kurdistan
region. The Kurdistan region government has paid great attention for
this dome to provide the fuel for Kurdistan region. However, the
Khurmala associated natural gas is currently flaring at the field.
Moreover, nowadays there is a plan to recover and trade this gas and
to use it either as feedstock to power station or to sell it in global
market. However, the laboratory analysis has showed that the
Khurmala sour gas has huge quantities of H2S about (5.3%) and CO2
about (4.4%). Indeed, Khurmala gas sweetening process has been
removed in previous study by using Aspen HYSYS. However,
Khurmala sweet gas still contents some quintets of water about 23
ppm in sweet gas stream. This amount of water should be removed or
reduced. Indeed, water content in natural gas cause several technical
problems such as hydrates and corrosion. Therefore, this study aims
to simulate the prospective Khurmala gas dehydration process by
using Aspen HYSYS V. 7.3 program. Moreover, the simulation
process succeeded in reducing the water content to less than 0.1ppm.
In addition, the simulation work is also achieved process
optimization by using several desiccant types for example, TEG and
DEG and it also study the relationship between absorbents type and
its circulation rate with HCs losses from glycol regenerator tower.
Abstract: In a bi-fuel diesel engine, the carburetor plays a vital
role in switching from fuel gas to petrol mode operation and viceversa.
The carburetor is the most important part of the fuel system of
a diesel engine. All diesel engines carry variable venturi mixer
carburetors. The basic operation of the carburetor mainly depends on
the restriction barrel called the venturi. When air flows through the
venturi, its speed increases and its pressure decreases. The main
challenge focuses on designing a mixing device which mixes the
supplied gas is the incoming air at an optimum ratio. In order to
surmount the identified problems, the way fuel gas and air flow in
the mixer have to be analyzed. In this case, the Computational Fluid
Dynamics or CFD approach is applied in design of the prototype
mixer. The present work is aimed at further understanding of the air
and fuel flow structure by performing CFD studies using a software
code. In this study for mixing air and gas in the condition that has
been mentioned in continuance, some mixers have been designed.
Then using of computational fluid dynamics, the optimum mixer has
been selected. The results indicated that mixer with 12 holes can
produce a homogenous mixture than those of 8-holes and 6-holes
mixer. Also the result showed that if inlet convergency was smoother
than outlet divergency, the mixture get more homogenous, the reason
of that is in increasing turbulence in outlet divergency.
Abstract: Plackett-Burman statistical screening of media
constituents and operational conditions for extracellular lipase
production from isolate Trichoderma viride has been carried out in
submerged fermentation. This statistical design is used in the early
stages of experimentation to screen out unimportant factors from a
large number of possible factors. This design involves screening of
up to 'n-1' variables in just 'n' number of experiments. Regression
coefficients and t-values were calculated by subjecting the
experimental data to statistical analysis using Minitab version 15.
The effects of nine process variables were studied in twelve
experimental trials. Maximum lipase activity of 7.83 μmol /ml /min
was obtained in the 6th trail. Pareto chart illustrates the order of
significance of the variables affecting the lipase production. The
present study concludes that the most significant variables affecting
lipase production were found to be palm oil, yeast extract, K2HPO4,
MgSO4 and CaCl2.
Abstract: This work has been carried out in order to provide an understanding of the physical behaviors of the flow variation of pressure and temperature in a vortex tube. A computational fluid dynamics model is used to predict the flow fields and the associated temperature separation within a Ranque–Hilsch vortex tube. The CFD model is a steady axisymmetric model (with swirl) that utilizes the standard k-ε turbulence model. The second–order numerical schemes, was used to carry out all the computations. Vortex tube with a circumferential inlet stream and an axial (cold) outlet stream and a circumferential (hot) outlet stream was considered. Performance curves (temperature separation versus cold outlet mass fraction) were obtained for a specific vortex tube with a given inlet mass flow rate. Simulations have been carried out for varying amounts of cold outlet mass flow rates. The model results have a good agreement with experimental data.
Abstract: This article makes and attempt to disclose the
dynamics of development of social interactions in an aggravated
environment in relation to the distinctive features of religious wars
and their negative impact to the society. Crisis situations that took
place in all spheres of social life are described, on the grounds of
which the author comes to specific conclusions.
Abstract: In this study, the powders of Ni and Ti with 50.5 at.%
Ni for 12 h were blended and cold pressed at the different pressures
(50, 75 and100 MPa).The porous product obtained after Ni-Ti
compacts were synthesized by SHS (self-propagating hightemperature
synthesis) in the different preheating temperatures (200,
250 and 300oC) and heating rates (30, 60 and 90oC/min). The effects
of the pressure, preheating temperature and heating rate were
investigated on biocompatibility in vivo. The porosity in the
synthesized products was in the range of 50.7–59.7 vol. %. The
pressure, preheating temperature and heating rate were found to have
an important effect on the biocompatibility in-vivo of the synthesized
products. Max. fibrotic tissue within the porous implant was found in
vivo periods (6 months), in which compacting pressure 100MPa.
Abstract: Artificial Neural Network (ANN) has been
extensively used for classification of heart sounds for its
discriminative training ability and easy implementation. However, it
suffers from overparameterization if the number of nodes is not
chosen properly. In such cases, when the dataset has redundancy
within it, ANN is trained along with this redundant information that
results in poor validation. Also a larger network means more
computational expense resulting more hardware and time related
cost. Therefore, an optimum design of neural network is needed
towards real-time detection of pathological patterns, if any from heart
sound signal. The aims of this work are to (i) select a set of input
features that are effective for identification of heart sound signals and
(ii) make certain optimum selection of nodes in the hidden layer for a
more effective ANN structure. Here, we present an optimization
technique that involves Singular Value Decomposition (SVD) and
QR factorization with column pivoting (QRcp) methodology to
optimize empirically chosen over-parameterized ANN structure.
Input nodes present in ANN structure is optimized by SVD followed
by QRcp while only SVD is required to prune undesirable hidden
nodes. The result is presented for classifying 12 common
pathological cases and normal heart sound.
Abstract: The most Malaria cases are occur along Thai-Mynmar border. Mathematical model for the transmission of Plasmodium falciparum and Plasmodium vivax malaria in a mixed population of Thais and migrant Burmese living along the Thai-Myanmar Border is studied. The population is separated into two groups, Thai and Burmese. Each population is divided into susceptible, infected, dormant and recovered subclasses. The loss of immunity by individuals in the infected class causes them to move back into the susceptible class. The person who is infected with Plasmodium vivax and is a member of the dormant class can relapse back into the infected class. A standard dynamical method is used to analyze the behaviors of the model. Two stable equilibrium states, a disease-free state and an epidemic state, are found to be possible in each population. A disease-free equilibrium state in the Thai population occurs when there are no infected Burmese entering the community. When infected Burmese enter the Thai community, an epidemic state can occur. It is found that the disease-free state is stable when the threshold number is less than one. The epidemic state is stable when a second threshold number is greater than one. Numerical simulations are used to confirm the results of our model.