Abstract: The Navier–Stokes equations for unsteady, incompressible, viscous fluids in the axisymmetric coordinate system are solved using a control volume method. The volume-of-fluid (VOF) technique is used to track the free-surface of the liquid. Model predictions are in good agreement with experimental measurements. It is found that the dynamic processes after impact are sensitive to the initial droplet velocity and the liquid pool depth. The time evolution of the crown height and diameter are obtained by numerical simulation. The critical We number for splashing (Wecr) is studied for Oh (Ohnesorge) numbers in the range of 0.01~0.1; the results compares well with those of the experiments.
Abstract: Groundwater is one of the most important water resources in Fars province. Based on this study, 95 percent of the total annual water consumption in Fars is used for agriculture, whereas the percentages for domestic and industrial uses are 4 and 1 percent, respectively. Population growth, urban and industrial growth, and agricultural development in Fars have created a condition of water stress. In this province, farmers and other users are pumping groundwater faster than its natural replenishment rate, causing a continuous drop in groundwater tables and depletion of this resource. In this research variation of groundwater level , their effects and ways to help control groundwater levels in some plains of Fars were evaluated .Excessive exploitation of groundwater in Darab, Jahrom, Estahban, Arsanjan, Khir and Niriz plains of Fars caused the groundwater levels fall too fast or to unacceptable levels. The average drawdown of the water table in Arsanjan, Khir. Estahban and Niriz plain plains were 12,8, 9 and 6 meters during 16,11,11 and 13 years ago respectively. This not only reduces available water resources and well yields but also can saline water intrusion, reductions in river flow and in wetland areas , drying springs, and ground subsidence, considerable increase in pumping costs and a significant decline in crop yields as a result of the increasing salinity. Finally based on situation and condition of the aquifer some suggestions are recommended.
Abstract: Heavy rainfall greatly affects the aerodynamic performance of the aircraft. There are many accidents of aircraft caused by aerodynamic efficiency degradation by heavy rain. In this Paper we have studied the heavy rain effects on the aerodynamic efficiency of NACA 64-210 & NACA 0012 airfoils. For our analysis, CFD method and preprocessing grid generator are used as our main analytical tools, and the simulation of rain is accomplished via two phase flow approach-s Discrete Phase Model (DPM). Raindrops are assumed to be non-interacting, non-deforming, non-evaporating and non-spinning spheres. Both airfoil sections exhibited significant reduction in lift and increase in drag for a given lift condition in simulated rain. The most significant difference between these two airfoils was the sensitivity of the NACA 64-210 to liquid water content (LWC), while NACA 0012 performance losses in the rain environment is not a function of LWC . It is expected that the quantitative information gained in this paper will be useful to the operational airline industry and greater effort such as small scale and full scale flight tests should put in this direction to further improve aviation safety.
Abstract: In this paper the problem of face recognition under variable illumination conditions is considered. Most of the works in the literature exhibit good performance under strictly controlled acquisition conditions, but the performance drastically drop when changes in pose and illumination occur, so that recently number of approaches have been proposed to deal with such variability. The aim of this work is to introduce an efficient local appearance feature extraction method based steerable pyramid (SP) for face recognition. Local information is extracted from SP sub-bands using LBP(Local binary Pattern). The underlying statistics allow us to reduce the required amount of data to be stored. The experiments carried out on different face databases confirm the effectiveness of the proposed approach.
Abstract: In this work, we study the impact of dynamically
changing link slowdowns on the stability properties of packetswitched
networks under the Adversarial Queueing Theory
framework. Especially, we consider the Adversarial, Quasi-Static
Slowdown Queueing Theory model, where each link slowdown may
take on values in the two-valued set of integers {1, D} with D > 1
which remain fixed for a long time, under a (w, ¤ü)-adversary. In this
framework, we present an innovative systematic construction for the
estimation of adversarial injection rate lower bounds, which, if
exceeded, cause instability in networks that use the LIS (Longest-in-
System) protocol for contention-resolution. In addition, we show that
a network that uses the LIS protocol for contention-resolution may
result in dropping its instability bound at injection rates ¤ü > 0 when
the network size and the high slowdown D take large values. This is
the best ever known instability lower bound for LIS networks.
Abstract: The paper reports on the results of experimental and
numerical study of nonstationary swirling flow in an isothermal
model of vortex burner. It has been identified that main source of the
instability is related to a precessing vortex core (PVC) phenomenon.
The PVC induced flow pulsation characteristics such as precession
frequency and its variation as a function of flowrate and swirl number
have been explored making use of acoustic probes. Additionally
pressure transducers were used to measure the pressure drops on the
working chamber and across the vortex flow. The experiments have
been included also the mean velocity measurements making use of a
laser-Doppler anemometry. The features of instantaneous flowfield
generated by the PVC were analyzed employing a commercial CFD
code (Star-CCM+) based on Detached Eddy Simulation (DES)
approach. Validity of the numerical code has been checked by
comparison calculated flowfield data with the obtained experimental
results. It has been confirmed particularly that the CFD code applied
correctly reproduces the flow features.
Abstract: A new strategy for oriented immobilization of proteins was proposed. The strategy contains two steps. The first step is to search for a docking site away from the active site on the protein surface. The second step is trying to find a ligand that is able to grasp the targeted site of the protein. To avoid ligand binding to the active site of protein, the targeted docking site is selected to own opposite charges to those near the active site. To enhance the ligand-protein binding, both hydrophobic and electrostatic interactions need to be included. The targeted docking site should therefore contain hydrophobic amino acids. The ligand is then selected through the help of molecular docking simulations. The enzyme α-amylase derived from Aspergillus oryzae (TAKA) was taken as an example for oriented immobilization. The active site of TAKA is surrounded by negatively charged amino acids. All the possible hydrophobic sites on the surface of TAKA were evaluated by the free energy estimation through benzene docking. A hydrophobic site on the opposite side of TAKA-s active site was found to be positive in net charges. A possible ligand, 3,3-,4,4- – Biphenyltetra- carboxylic acid (BPTA), was found to catch TAKA by the designated docking site. Then, the BPTA molecules were grafted onto silica gels and measured the affinity of TAKA adsorption and the specific activity of thereby immobilized enzymes. It was found that TAKA had a dissociation constant as low as 7.0×10-6 M toward the ligand BPTA on silica gel. The increase in ionic strength has little effect on the adsorption of TAKA, which indicated the existence of hydrophobic interaction between ligands and proteins. The specific activity of the immobilized TAKA was compared with the randomly adsorbed TAKA on primary amine containing silica gel. It was found that the orderly immobilized TAKA owns a specific activity twice as high as the one randomly adsorbed by ionic interaction.
Abstract: A mobile Ad-hoc network consists of wireless nodes
communicating without the need for a centralized administration. A
user can move anytime in an ad hoc scenario and, as a result, such a
network needs to have routing protocols which can adopt
dynamically changing topology. To accomplish this, a number of ad
hoc routing protocols have been proposed and implemented, which
include DSR, OLSR and AODV. This paper presents a study on the
QoS parameters for MANET application traffics in large-scale
scenarios with 50 and 120 nodes. The application traffics analyzed in
this study is File Transfer Protocol (FTP). In large scale networks
(120 nodes) OLSR shows better performance and in smaller scale
networks (50 nodes)AODV shows less packet drop rate and OLSR
shows better throughput.
Abstract: Automated operations based on voice commands will become more and more important in many applications, including robotics, maintenance operations, etc. However, voice command recognition rates drop quite a lot under non-stationary and chaotic noise environments. In this paper, we tried to significantly improve the speech recognition rates under non-stationary noise environments. First, 298 Navy acronyms have been selected for automatic speech recognition. Data sets were collected under 4 types of noisy environments: factory, buccaneer jet, babble noise in a canteen, and destroyer. Within each noisy environment, 4 levels (5 dB, 15 dB, 25 dB, and clean) of Signal-to-Noise Ratio (SNR) were introduced to corrupt the speech. Second, a new algorithm to estimate speech or no speech regions has been developed, implemented, and evaluated. Third, extensive simulations were carried out. It was found that the combination of the new algorithm, the proper selection of language model and a customized training of the speech recognizer based on clean speech yielded very high recognition rates, which are between 80% and 90% for the four different noisy conditions. Fourth, extensive comparative studies have also been carried out.
Abstract: Synthetic juice clarification was done through spiral
wound ultrafiltration (UF) membrane module. Synthetic juice was
clarified at two different operating conditions, such as, with and
without permeates recycle at turbulent flow regime. The performance
of spiral wound ultrafiltration membrane was analyzed during
clarification of synthetic juice. Synthetic juice was the mixture of
deionized water, sucrose and pectin molecule. The operating
conditions are: feed flowrate of 10 lpm, pressure drop of 413.7 kPa
and Reynolds no of 5000. Permeate sample was analyzed in terms of
volume reduction factor (VRF), viscosity (Pa.s), ⁰Brix, TDS (mg/l),
electrical conductivity (μS) and turbidity (NTU). It was observe that
the permeate flux declined with operating time for both conditions of
with and without permeate recycle due to increase of concentration
polarization and increase of gel layer on membrane surface. For
without permeate recycle, the membrane fouling rate was faster
compared to with permeate recycle. For without permeate recycle,
the VRF rose up to 5 and for with recycle permeate the VRF is 1.9.
The VRF is higher due to adsorption of solute (pectin) molecule on
membrane surface and resulting permeateflux declined with VRF.
With permeate recycle, quality was within acceptable limit. Fouled
membrane was cleaned by applying different processes (e.g.,
deionized water, SDS and EDTA solution). Membrane cleaning was
analyzed in terms of permeability recovery.
Abstract: In elevating performance in competetive sports, an
athlete must continously train in achieving maximum
performance,but needs to pay attention to recovery therapy, that is to
recover from fatigue as well as injury.The correct recovery therapy
will assist in process of recovery and helps in the training in
achieving better performace. Binahong (Anredera cordifolia) was
proven empirically by the locals in assisting speedy recovery from an
injury.Clinical research with lab animals receiving blunt trauma
injury, microscopically shown signs of: 1) redness, 2) heatiness, 3)
swelling and, 4) lack of activity. There is also microscopic indication
of: 1) infiltration of inflame cells (migration of cells to the trauma
area), 2) Cells necrosis, 3) Congestion (as a result of dead red blood
cells), 4) uedema. On administration of Binahong for 3 days, there is
a significant drop of 5% in cell inflammation, 2% increase of
fibroblast (cell membrance) count.Conclutin: Binahong do assist in
reducing cell inflammation and increase counts of cells fibroblast.
Suggestion: In helping athlete's to recover from force injury, we need
study about Binahong's roots to inflammation cell and healing of
injuried cell.
Abstract: In hypersonic environments, the aerothermal effect
makes it difficult for the optical side windows of optical guided
missiles to withstand high heat. This produces cracking or breaking,
resulting in an inability to function. This study used computational
fluid mechanics to investigate the external cooling jet conditions of
optical side windows. The turbulent models k-ε and k-ω were
simulated. To be in better accord with actual aerothermal
environments, a thermal radiation model was added to examine
suitable amounts of external coolants and the optical window
problems of aero-thermodynamics. The simulation results indicate that
when there are no external cooling jets, because airflow on the optical
window and the tail groove produce vortices, the temperatures in these
two locations reach a peak of approximately 1600 K. When the
external cooling jets worked at 0.15 kg/s, the surface temperature of
the optical windows dropped to approximately 280 K. When adding
thermal radiation conditions, because heat flux dissipation was faster,
the surface temperature of the optical windows fell from 280 K to
approximately 260 K. The difference in influence of the different
turbulence models k-ε and k-ω on optical window surface temperature
was not significant.
Abstract: Turbine blade cooling is considered as the most
effective way of maintaining high operating temperature making use
of the available materials, and turbine systems with wet compression
have a potential for future power generation because of high efficiency
and high specific power with a relatively low cost. In this paper
performance analysis of wet-compression gas turbine cycle with
turbine blade cooling is carried out. The wet compression process is
analytically modeled based on non-equilibrium droplet evaporation.
Special attention is paid for the effects of pressure ratio and water
injection ratio on the important system variables such as ratio of
coolant fluid flow, fuel consumption, thermal efficiency and specific
power. Parametric studies show that wet compression leads to
insignificant improvement in thermal efficiency but significant
enhancement of specific power in gas turbine systems with turbine
blade cooling.
Abstract: This paper was to study the clothes dryer using waste
heat from a split type air conditioner with a capacity of 12,648 btu/h.
The drying chamber had a minimum cross section area with the size
of 0.5 x 1.0 m2. The chamber was constructed by sailcloth and was
inside folded with aluminium foil. Then, it was connected to the
condensing unit of an air conditioner. The experiment was carried out
in two aspects which were the clothes drying with and without
auxiliary fan unit. The results showed that the drying rate of clothes
in the chamber installed with and without auxiliary fan unit were
2.26 and 1.1 kg/h, respectively. In case of the chamber installed with
a auxiliary fan unit, the additional power of 0.011 kWh was
consumed and the drying rate was higher than that of clothes drying
without auxiliary fan unit. Without auxiliary fan unit installation, no
energy was required but there was a portion of hot air leaks away
through the punctured holes at the wall of the drying chamber, hence
the drying rate was dropped below. The drying rate of clothes drying
using waste heat was higher than natural indoor drying and
commercial dryer which their drying rate were 0.17 and 1.9 kg/h,
respectively. It was noted that the COP of the air conditioner did not
change during the operating of clothes drying.
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: Droplet size distributions in the cold spray of a fuel
are important in observed combustion behavior. Specification of
droplet size and velocity distributions in the immediate downstream
of injectors is also essential as boundary conditions for advanced
computational fluid dynamics (CFD) and two-phase spray transport
calculations. This paper describes the development of a new model to
be incorporated into maximum entropy principle (MEP) formalism
for prediction of droplet size distribution in droplet formation region.
The MEP approach can predict the most likely droplet size and
velocity distributions under a set of constraints expressing the
available information related to the distribution.
In this article, by considering the mechanisms of turbulence
generation inside the nozzle and wave growth on jet surface, it is
attempted to provide a logical framework coupling the flow inside the
nozzle to the resulting atomization process. The purpose of this paper
is to describe the formulation of this new model and to incorporate it
into the maximum entropy principle (MEP) by coupling sub-models
together using source terms of momentum and energy. Comparison
between the model prediction and experimental data for a gas turbine
swirling nozzle and an annular spray indicate good agreement
between model and experiment.
Abstract: Sensor networks are often deployed in unattended
environments, thus leaving these networks vulnerable to false data
injection attacks in which an adversary injects forged reports into the
network through compromised nodes, with the goal of deceiving the
base station or depleting the resources of forwarding nodes. Several
research solutions have been recently proposed to detect and drop such
forged reports during the forwarding process. Each design can provide
the equivalent resilience in terms of node compromising. However,
their energy consumption characteristics differ from each other. Thus,
employing only a single filtering scheme for a network is not a
recommendable strategy in terms of energy saving. It's very important
the threshold determination for message authentication to identify. We
propose the recursive contract net protocols which less energy level of
terminal node in wireless sensor network.
Abstract: The study was performed to evaluate the effect of Sgirdling,
fruit thinning plus bagging with 2,4-D application, fruit
thinning plus bagging on growth and quality of wax apple fruit.
Girdling was applied three week before flowering. The 2,4-D was
sprayed at the small bud and petal fall stage. The effect of all
treatments on fruit growth was measured weekly. The physical and
biochemical quality characteristics of the fruits were recorded. The
results showed that no significant effect on number of bud among
treatments. S-girdling, 2,4-D application produced the lowest bud
drop, fruit drop compared to untreated control. Moreover, S-girdling
enhanced faster fruit growth producing the best final fruit length and
diameter than the control treatment. It was also observed that Sgirdling
greatly increased fruit set, fruit weight as well as total
soluble solid, reduced fruit crack, and titratable acidity. In
conclusion, S-girdling had a distinctive and significant effect on most
of the fruit quality characteristics assessed. Application 2,4-D was
also recommended as the industry norm to increase fruit set, and fruit
quality in wax apple.
Abstract: Dual phase steels (DPS)s have a microstructure
consisting of a hard second phase called Martensite in the soft Ferrite
matrix. In recent years, there has been interest in dual-phase steels,
because the application of these materials has made significant usage;
particularly in the automotive sector Composite microstructure of
(DPS)s exhibit interesting characteristic mechanical properties such
as continuous yielding, low yield stress to tensile strength
ratios(YS/UTS), and relatively high formability; which offer
advantages compared with conventional high strength low alloy
steels(HSLAS). The research dealt with the characterization of
damage in (DPS)s. In this study by review the mechanisms of failure
due to volume fraction of martensite second phase; a new method is
introduced to identifying the mechanisms of failure in the various
phases of these types of steels. In this method the acoustic emission
(AE) technique was used to detect damage progression. These failure
mechanisms consist of Ferrite-Martensite interface decohesion and/or
martensite phase fracture. For this aim, dual phase steels with
different volume fraction of martensite second phase has provided by
various heat treatment methods on a low carbon steel (0.1% C), and
then AE monitoring is used during tensile test of these DPSs. From
AE measurements and an energy ratio curve elaborated from the
value of AE energy (it was obtained as the ratio between the strain
energy to the acoustic energy), that allows detecting important
events, corresponding to the sudden drops. These AE signals events
associated with various failure mechanisms are classified for ferrite
and (DPS)s with various amount of Vm and different martensite
morphology. It is found that AE energy increase with increasing Vm.
This increasing of AE energy is because of more contribution of
martensite fracture in the failure of samples with higher Vm. Final
results show a good relationship between the AE signals and the
mechanisms of failure.
Abstract: The objective of this research is to examine the shear thinning behaviour of mixing flow of non-Newtonian fluid like toothpaste in the dissolution container with rotating stirrer. The problem under investigation is related to the chemical industry. Mixing of fluid is performed in a cylindrical container with rotating stirrer, where stirrer is eccentrically placed on the lid of the container. For the simulation purpose the associated motion of the fluid is considered as revolving of the container, with stick stirrer. For numerical prediction, a time-stepping finite element algorithm in a cylindrical polar coordinate system is adopted based on semi-implicit Taylor-Galerkin/pressure-correction scheme. Numerical solutions are obtained for non-Newtonian fluids employing power law model. Variations with power law index have been analysed, with respect to the flow structure and pressure drop.