Abstract: The effect of flooding can be a serious problem for
wheat farmers, even at dry land condition. Amount of flooding
damage depends on duration flooding, developmental stage, wheat
type and variety. Therefore as a factorial experiment in randomized
complete design based on winter bread wheat cultivars (Pishtaz,
Marvdasht, Shiraz, Zarin, Shahriar, C-81-4, Sardari, Agosta seed,
FGS and Azar2) at stages (Non- flooding stress, flooding at tillering
and stem elongation stages for 15 days) carried out in Faculty of
Agriculture, Razi University, Kermanshah, Iran. During flooding,
soil environment of plant roots were water saturated. Analysis of
variance showed that flooding had a significant effect on the number
of grains per spike, grain weight per spike and a grain weight. Hence
flooding reduces the number of grain per spike between 27.1 to 42.5
percent, grain weight per spike between 34.7 to 54.4 percent and
single grain weight between 12.1 to 15.1 percent. Effects of flooding
at the tillering stage reduced higher than stem elongation stage on
studied traits. The result also showed that flooding at tillering stage
delayed spikelet primordial and floret. Between wheat cultivars was
significant for traits, but were different reactions. "Shiraz", "Zarin"
and "Shahriar" had the most no. grain per spike, but "Zarin" and
"Sardari" had the most grain weight per spike and single grain
weight, respectively. Also, interaction between start of flooding and
cultivar was significant.
Abstract: Geopolymer cement was evaluated as wellbore sealing material for carbon dioxide geosequestration application. Curing of cement system in saline water and strength testing in triaxial stress state condition under lateral confinement is relevant to primary cementing in CO2 geosequestration wellbore in saline aquifer. Geopolymer cement was cured in saline water (both at ambient conditions for 28 days and heated (60°C) conditions for 12 hours) and tested for triaxial strength at different levels of lateral confinement. Normal water and few other curing techniques were also studied both for geopolymer and API ‘G’ cement. Results reported were compared to evaluate the suitability of saline water for curing of geopolymer cement. Unconfined compression test results showed higher strength for curing in saline water than normal water. Besides, testing strength under lateral confinement demonstrated the material failure behavior from brittle to plastic.
Abstract: A numerical study on the turbulent flow and heat
transfer characteristics in the rectangular channel with different types
of baffles is carried out. The inclined baffles have the width of 19.8
cm, the square diamond type hole having one side length of 2.55 cm,
and the inclination angle of 5o. Reynolds number is varied between
23,000 and 57,000. The SST turbulence model is applied in the
calculation. The validity of the numerical results is examined by the
experimental data. The numerical results of the flow field depict that
the flow patterns around the different baffle type are entirely different
and these significantly affect the local heat transfer characteristics.
The heat transfer and friction factor characteristics are significantly
affected by the perforation density of the baffle plate. It is found that
the heat transfer enhancement of baffle type II (3 hole baffle) has the
best values.
Abstract: The Taiwan Health Literacy Scale (THLS) was developed to cope with the need of measuring heath literacy of Chinese-speaking adults in Taiwan. Although the scale was proven having good reliability and validity, it was not popularly adopted by the practitioners due to the length, and the time required completing. Based on the THLS, this research further invited healthcare professionals to review the original scale for a possible shorten work. Under the logic of THLS, the research adopted an analytic hierarchy process technique to consolidate the healthcare experts- assessments to shorten the original scale. There are fifteen items out of the original 66 items were identified having higher loadings. Confirmed by the experts and passed a pilot test with 40 undergraduate students, a short form of THLS is then introduced. This research then used 839 samples from the major cities of the Hua-lien county in the eastern part of Taiwan to test the reliability and validity of this new scale. The reliability of the scale is high and acceptable. The current scale is also highly correlated with the original, of which provide evidence for the validity of the scale.
Abstract: This paper examines the forced convection flow of
incompressible, electrically conducting viscous fluid past a sharp
wedge in the presence of heat generation or absorption with an
applied magnetic field. The system of partial differential equations
governing Falkner - Skan wedge flow and heat transfer is first
transformed into a system of ordinary differential equations using
similarity transformations which is later solved using an implicit
finite - difference scheme, along with quasilinearization technique.
Numerical computations are performed for air (Pr = 0.7) and
displayed graphically to illustrate the influence of pertinent physical
parameters on local skin friction and heat transfer coefficients and,
also on, velocity and temperature fields. It is observed that the
magnetic field increases both the coefficients of skin friction and heat
transfer. The effect of heat generation or absorption is found to be
very significant on heat transfer, but its effect on the skin friction is
negligible. Indeed, the occurrence of overshoot is noticed in the
temperature profiles during heat generation process, causing the
reversal in the direction of heat transfer.
Abstract: This paper presents the development and application of an adaptive neuro fuzzy inference system (ANFIS) based intelligent hybrid neuro fuzzy controller for automatic generation control (AGC) of two-area interconnected thermal power system with reheat non linearity. The dynamic response of the system has been studied for 1% step load perturbation in area-1. The performance of the proposed neuro fuzzy controller is compared against conventional proportional-integral (PI) controller, state feedback linear quadratic regulator (LQR) controller and fuzzy gain scheduled proportionalintegral (FGSPI) controller. Comparative analysis demonstrates that the proposed intelligent neuro fuzzy controller is the most effective of all in improving the transients of frequency and tie-line power deviations against small step load disturbances. Simulations have been performed using Matlab®.
Abstract: The modeling of water transfer in the unsaturated zone
uses techniques and methods of the soil physics to solve the
Richards-s equation. However, there is a disaccord between the size
of the measurements provided by the soil physics and the size of the
fields of hydrological modeling problem, to which is added the
strong spatial variability of soil hydraulic properties. The objective of
this work was to develop a methodology to estimate the
hydrodynamic parameters for modeling water transfers at different
hydrological scales in the soil-plant atmosphere systems.
Abstract: In this article, using finite element analysis (FEA)
and an X-ray diffractometer (XRD), cold-sprayed titanium particles
on a steel substrate is investigated in term of cooling time and the
development of residual strains. Three cooling-down models of
sprayed particles after deposition stage are simulated and discussed:
the first model (m1) considers conduction effect to the substrate only,
the second model (m2) considers both conduction as well as
convection effect to the environment, and the third model (m3) which
is the same as the second model but with the substrate heated to a
near particle temperature before spraying. Thereafter, residual strains
developed in the third model is compared with the experimental
measurement of residual strains, which involved a Bruker D8
Advance Diffractometer using CuKa radiation (40kV, 40mA)
monochromatised with a graphite sample monochromator. For
deposition conditions of this study, a good correlation was found to
exist between the FEA results and XRD measurements of residual
strains.
Abstract: Since polymerase chain reaction (PCR) has been
invented, it has emerged as a powerful tool in genetic analysis. The
PCR products are closely linked with thermal cycles. Therefore, to
reduce the reaction time and make temperature distribution uniform in
the reaction chamber, a novel oscillatory thermal cycler is designed.
The sample is placed in a fixed chamber, and three constant isothermal
zones are established and lined in the system. The sample is oscillated
and contacted with three different isothermal zones to complete
thermal cycles. This study presents the design of the geometric
characteristics of the chamber. The commercial software
CFD-ACE+TM is utilized to investigate the influences of various
materials, heating times, chamber volumes, and moving speed of the
chamber on the temperature distributions inside the chamber. The
chamber moves at a specific velocity and the boundary conditions
with time variations are related to the moving speed. Whereas the
chamber moves, the boundary is specified at the conditions of the
convection or the uniform temperature. The user subroutines compiled
by the FORTRAN language are used to make the numerical results
realistically. Results show that the reaction chamber with a rectangular
prism is heated on six faces; the effects of various moving speeds of
the chamber on the temperature distributions are examined. Regarding
to the temperature profiles and the standard deviation of the
temperature at the Y-cut cross section, the non-uniform temperature
inside chamber is found as the moving speed is larger than 0.01 m/s.
By reducing the heating faces to four, the standard deviation of the
temperature of the reaction chamber is under 1.4×10-3K with the range
of velocities between 0.0001 m/s and 1 m/s. The nature convective
boundary conditions are set at all boundaries while the chamber moves
between two heaters, the effects of various moving velocities of the
chamber on the temperature distributions are negligible at the assigned
time duration.
Abstract: The autonomic nervous system has a regulatory
structure that helps people adapt to changes in their environment by
adjusting or modifying some functions in response to stress, and regulating involuntary function of human organs. The purpose of this
study was to investigate the effect of combined stimulation, both
far-infrared heating and chiropractic, on the autonomic nervous system
activities using thermal image and heart rate variability. Six healthy subjects participated in this test. We compared the before and after
autonomic nervous system activities through obtaining thermal image
and photoplethysmogram signal. The thermal images showed that the
combined stimulation changed subject-s body temperature more
highly and widely than before. The result of heart rate variability
indicated that LF/HF ratio decreased. We concluded that combined
stimulation activates autonomic nervous system, and expected other
possibilities of this combined stimulation.
Abstract: Understanding how precipitation inter-annually
changes and its implication in agricultural drought and production change in winter wheat (Triticum aestivum L.) growth season is critical for crop production in China. MODIS Temperature-Vegetation Dryness Index (TVDI) and daily mean precipitation time series for the main growth season(Feb. to May) of winter wheat from 2000 to 2010
were used to analyze the distribution of trends of precipitation,
agricultural drought and winter wheat yield change respectively, and
relationships between them in North China region(Huang-huai-hai
region, HHH region), China. The results indicated that the trend of
precipitation in HHH region past 11 years was increasing, which had
induced generally corresponding decreasing trend of agricultural
drought and increasing trend of wheat yield, while the trend of drought
was spatially diverse. The study could provide a basis for agricultural
drought research during winter wheat season in HHH region under the
ground of climate change.
Abstract: Among all mechanical joining processes, welding has
been employed for its advantage in design flexibility, cost saving,
reduced overall weight and enhanced structural performance.
However, for structures made of relatively thin components, welding
can introduce significant buckling distortion which causes loss of
dimensional control, structural integrity and increased fabrication
costs. Different parameters can affect buckling behavior of welded
thin structures such as, heat input, welding sequence, dimension of
structure. In this work, a 3-D thermo elastic-viscoplastic finite
element analysis technique is applied to evaluate the effect of shell
dimensions on buckling behavior and entropy generation of welded
thin shells. Also, in the present work, the approximated longitudinal
transient stresses which produced in each time step, is applied to the
3D-eigenvalue analysis to ratify predicted buckling time and
corresponding eigenmode. Besides, the possibility of buckling
prediction by entropy generation at each time is investigated and it is
found that one can predict time of buckling with drawing entropy
generation versus out of plane deformation. The results of finite
element analysis show that the length, span and thickness of welded
thin shells affect the number of local buckling, mode shape of global
buckling and post-buckling behavior of welded thin shells.
Abstract: The B'enard-Marangoni thermal instability problem for
a viscoelastic Jeffreys- fluid layer with internal heat generation is
investigated. The fluid layer is bounded above by a realistic free
deformable surface and by a plane surface below. Our analysis
shows that while the internal heat generation and the relaxation time
both destabilize the fluid layer, its stability may be enhanced by an
increased retardation time.
Abstract: A topologically oriented neural network is very
efficient for real-time path planning for a mobile robot in changing
environments. When using a recurrent neural network for this
purpose and with the combination of the partial differential equation
of heat transfer and the distributed potential concept of the network,
the problem of obstacle avoidance of trajectory planning for a
moving robot can be efficiently solved. The related dimensional
network represents the state variables and the topology of the robot's
working space. In this paper two approaches to problem solution are
proposed. The first approach relies on the potential distribution of
attraction distributed around the moving target, acting as a unique
local extreme in the net, with the gradient of the state variables
directing the current flow toward the source of the potential heat. The
second approach considers two attractive and repulsive potential
sources to decrease the time of potential distribution. Computer
simulations have been carried out to interrogate the performance of
the proposed approaches.
Abstract: In this study acoustic emission (AE) signals obtained during deformation and fracture of two types of ferrite-martensite dual phase steels (DPS) specimens have been analyzed in frequency domain. For this reason two low carbon steels with various amounts of carbon were chosen, and intercritically heat treated. In the introduced method, identifying the mechanisms of failure in the various phases of DPS is done. For this aim, AE monitoring has been used during tensile test of several DPS with various volume fraction of the martensite (VM) and attempted to relate the AE signals and failure mechanisms in these steels. Different signals, which referred to 2-3 micro-mechanisms of failure due to amount of carbon and also VM have been seen. By Fast Fourier Transformation (FFT) of signals in distinct locations, an excellent relationship between peak frequencies in these areas and micro-mechanisms of failure were seen. The results were verified by microscopic observations (SEM).
Abstract: In a bid to improve turbine entry temperature for maximizing the thermal efficiency of the HP stage gas turbine blade, an attempt is made in this paper to compare the performance of helicoidal ducted blade cooling with turbulator of different geometric proportion. It is found from analysis that there is significant improvement in cooling characteristics for turbine blade with turbulator geometry having larger e/D ratio. Also it is found from analysis, performance is vastly improved for greater thickness of turbulator geometry.
Abstract: An experimental study is realized in order to verify the
Mini Heat Pipe (MHP) concept for cooling high power dissipation
electronic components and determines the potential advantages of
constructing mini channels as an integrated part of a flat heat pipe. A
Flat Mini Heat Pipe (FMHP) prototype including a capillary structure
composed of parallel rectangular microchannels is manufactured and
a filling apparatus is developed in order to charge the FMHP. The
heat transfer improvement obtained by comparing the heat pipe
thermal resistance to the heat conduction thermal resistance of a
copper plate having the same dimensions as the tested FMHP is
demonstrated for different heat input flux rates. Moreover, the heat
transfer in the evaporator and condenser sections are analyzed, and
heat transfer laws are proposed. In the theoretical part of this work, a
detailed mathematical model of a FMHP with axial microchannels is
developed in which the fluid flow is considered along with the heat
and mass transfer processes during evaporation and condensation.
The model is based on the equations for the mass, momentum and
energy conservation, which are written for the evaporator, adiabatic,
and condenser zones. The model, which permits to simulate several
shapes of microchannels, can predict the maximum heat transfer
capacity of FMHP, the optimal fluid mass, and the flow and thermal
parameters along the FMHP. The comparison between experimental
and model results shows the good ability of the numerical model to
predict the axial temperature distribution along the FMHP.
Abstract: The fabrication of porous NiTi shape memory alloys (SMAs) from elemental powder compacts was conducted by selfpropagating high temperature synthesis (SHS). Effects of the preheating temperature and the chamber pressure on the combustion characteristics as well as the final morphology and the composition of products were studied. The samples with porosity between 56.4 and 59.0% under preheating temperature in the range of 200-300°C and Ar-gas chamber pressure of 138 and 201 kPa were obtained. The pore structures were found to be dissimilar only in the samples processed with different preheating temperature. The major phase in the porous product is NiTi with small amounts of secondary phases, NiTi2 and Ni4Ti3. The preheating temperature and the chamber pressure have very little effect on the phase constituent. While the combustion temperature of the sample was notably increased by increasing the preheating temperature, they were slightly changed by varying the chamber pressure.
Abstract: In this paper an extensive verification of the extraction
method (published earlier) that consistently accounts for self-heating
and Early effect to accurately extract both base and thermal resistance
of bipolar junction transistors is presented. The method verification is
demonstrated on advanced RF SiGe HBTs were the extracted results
for the thermal resistance are compared with those from another
published method that ignores the effect of Early effect on internal
base-emitter voltage and the extracted results of the base resistance
are compared with those determined from noise measurements. A
self-consistency of our method in the extracted base resistance and
thermal resistance using compact model simulation results is also
carried out in order to study the level of accuracy of the method.
Abstract: Regarding previous research studies it was concluded
that thin-walled fiber-cement composites are able to conduct electric
current under specific conditions. This property is ensured by using
of various kinds of carbon materials. Though carbon fibers are less
conductive than metal fibers, composites with carbon fibers were
evaluated as better current conductors than the composites with metal
fibers. The level of electric conductivity is monitored by the means of
impedance measurement of designed samples. These composites
could be used for a range of applications such as heating of
trafficable surfaces or shielding of electro-magnetic fields.
The aim of the present research was to design an element with the
ability to monitor internal processes in building structures and
prevent them from collapsing. As a typical element for laboratory
testing there was chosen a concrete column, which was repeatedly
subjected to load by simple pressure with continual monitoring of
changes in electrical properties.