Abstract: Exact solution of an unsteady flow of elastico-viscous
fluid through a porous media in a tube of ellipsoidal cross section
under the influence of constant pressure gradient has been obtained in
this paper. Initially, the flow is generated by a constant pressure
gradient. After attaining the steady state, the pressure gradient is
suddenly withdrawn and the resulting fluid motion in a tube of
ellipsoidal cross section by taking into account of the porosity factor
of the bounding surface is investigated. The problem is solved in twostages
the first stage is a steady motion in tube under the influence of
a constant pressure gradient, the second stage concern with an
unsteady motion. The problem is solved employing separation of
variables technique. The results are expressed in terms of a nondimensional
porosity parameter (K) and elastico-viscosity parameter
(β), which depends on the Non-Newtonian coefficient. The flow
parameters are found to be identical with that of Newtonian case as
elastic-viscosity parameter tends to zero and porosity tends to
infinity. It is seen that the effect of elastico-viscosity parameter and
the porosity parameter of the bounding surface has significant effect
on the velocity parameter.
Abstract: The dissimilar joint between aluminum/titanium
alloys (Al 6082 and Ti G2) were successfully achieved by CO2 laser
welding with a single pass and without filler material using the
overlap joint design. Laser welding parameters ranges combinations
were experimentally determined using Taguchi approach with the
objective of producing welded joint with acceptable welding profile
and high quality of mechanical properties. In this study a joining of
dissimilar Al 6082 / Ti G2 was resulted in three distinct regions
fusion area in the weldment. These regions are studied in terms of its
microstructural characteristics and microhardness which are directly
affecting the welding quality.
The weld metal was mainly composed of martensite alpha prime.
In two different metals in the two different sides of joint HAZ, grain
growth was detected. The microhardness of the joint distribution also
has shown microhardness increasing in the HAZ of two base metals
and a varying microhardness in fusion zone.
Abstract: The building sector is responsible, in many
industrialized countries, for about 40% of the total energy
requirements, so it seems necessary to devote some efforts in this
area in order to achieve a significant reduction of energy
consumption and of greenhouse gases emissions.
The paper presents a study aiming at providing a design
methodology able to identify the best configuration of the system
building/plant, from a technical, economic and environmentally point
of view.
Normally, the classical approach involves a building's energy
loads analysis under steady state conditions, and subsequent selection
of measures aimed at improving the energy performance, based on
previous experience made by architects and engineers in the design
team. Instead, the proposed approach uses a sequence of two wellknown
scientifically validated calculation methods (TRNSYS and
RETScreen), that allow quite a detailed feasibility analysis.
To assess the validity of the calculation model, an existing,
historical building in Central Italy, that will be the object of
restoration and preservative redevelopment, was selected as a casestudy.
The building is made of a basement and three floors, with a
total floor area of about 3,000 square meters.
The first step has been the determination of the heating and
cooling energy loads of the building in a dynamic regime by means,
which allows simulating the real energy needs of the building in
function of its use. Traditional methodologies, based as they are on
steady-state conditions, cannot faithfully reproduce the effects of
varying climatic conditions and of inertial properties of the structure.
With this model is possible to obtain quite accurate and reliable
results that allow identifying effective combinations building-HVAC
system.
The second step has consisted of using output data obtained as
input to the calculation model, which enables to compare different
system configurations from the energy, environmental and financial
point of view, with an analysis of investment, and operation and
maintenance costs, so allowing determining the economic benefit of
possible interventions.
The classical methodology often leads to the choice of
conventional plant systems, while our calculation model provides a
financial-economic assessment for innovative energy systems and
low environmental impact.
Computational analysis can help in the design phase, particularly
in the case of complex structures with centralized plant systems, by
comparing the data returned by the calculation model for different
design options.
Abstract: Comparing other methods of waste water treatment,
constructed wetlands are one of the most fascinating practices
because being a natural process they are eco-friendly have low
construction and maintenance cost and have considerable capability
of wastewater treatment. The current research was focused mainly on
comparison of Ranunculus muricatus and Typha latifolia as wetland
plants for domestic wastewater treatment by designing and
constructing efficient pilot scale horizontal subsurface flow
mesocosms. Parameters like chemical oxygen demand, biological
oxygen demand, phosphates, sulphates, nitrites, nitrates, and
pathogenic indicator microbes were studied continuously with
successive treatments. Treatment efficiency of the system increases
with passage of time and with increase in temperature. Efficiency of
T. latifolia planted setups in open environment was fairly good for
parameters like COD and BOD5 which was showing reduction up to
82.5% for COD and 82.6% for BOD5 while DO was increased up to
125%. Efficiency of R. muricatus vegetated setup was also good but
lowers than that of T. latifolia planted showing 80.95% removal of
COD and BOD5. Ranunculus muricatus was found effective in
reducing bacterial count in wastewater. Both macrophytes were
found promising in wastewater treatment.
Abstract: Cemented carbide balls are usually implemented in
industry under the environment of high speed, high temperature,
corrosiveness and strong collisions. However, its application is limited
due to high fabrication cost, processing efficiency and quality. A novel
eccentric lapping method with two rotatable lapping plates was
proposed in this paper. A mathematical model was constructed to
analyze the influence of each design parameter on this lapping method.
To validate this new lapping method, an orthogonal experiment was
conducted with cemented carbide balls (YG6). The simulation model
was verified and the optimal lapping parameters were derived. The
results show that the surface roundness of the balls reaches to 0.65um
from 2um in 1 hour using this lapping method. So, using this novel
lapping method, it can effectively improve the machining precision
and efficiency of cemented carbide balls.
Abstract: New physical insights into the nonlinear Lorenz
equations related to flow resistance is discussed in this work. The
chaotic dynamics related to Lorenz equations has been studied in
many papers, which is due to the sensitivity of Lorenz equations to
initial conditions and parameter uncertainties. However, the physical
implication arising from Lorenz equations about convectional motion
attracts little attention in the relevant literature. Therefore, as a first
step to understand the related fluid mechanics of convectional motion,
this paper derives the Lorenz equations again with different forced
conditions in the model. Simulation work of the modified Lorenz
equations without the viscosity or buoyancy force is discussed. The
time-domain simulation results may imply that the states of the
Lorenz equations are related to certain flow speed and flow resistance.
The flow speed of the underlying fluid system increases as the flow
resistance reduces. This observation would be helpful to analyze the
coupling effects of different fluid parameters in a convectional model
in future work.
Abstract: Pulmonary Function Tests are important non-invasive
diagnostic tests to assess respiratory impairments and provides
quantifiable measures of lung function. Spirometry is the most
frequently used measure of lung function and plays an essential role
in the diagnosis and management of pulmonary diseases. However,
the test requires considerable patient effort and cooperation,
markedly related to the age of patients resulting in incomplete data
sets. This paper presents, a nonlinear model built using Multivariate
adaptive regression splines and Random forest regression model to
predict the missing spirometric features. Random forest based feature
selection is used to enhance both the generalization capability and the
model interpretability. In the present study, flow-volume data are
recorded for N= 198 subjects. The ranked order of feature importance
index calculated by the random forests model shows that the
spirometric features FVC, FEF25, PEF, FEF25-75, FEF50 and the
demographic parameter height are the important descriptors. A
comparison of performance assessment of both models prove that, the
prediction ability of MARS with the `top two ranked features namely
the FVC and FEF25 is higher, yielding a model fit of R2= 0.96 and
R2= 0.99 for normal and abnormal subjects. The Root Mean Square
Error analysis of the RF model and the MARS model also shows that
the latter is capable of predicting the missing values of FEV1 with a
notably lower error value of 0.0191 (normal subjects) and 0.0106
(abnormal subjects) with the aforementioned input features. It is
concluded that combining feature selection with a prediction model
provides a minimum subset of predominant features to train the
model, as well as yielding better prediction performance. This
analysis can assist clinicians with a intelligence support system in the
medical diagnosis and improvement of clinical care.
Abstract: This work deals with parameter identification of
permanent magnet motors, a class of ac motor which is particularly
important in industrial automation due to characteristics like
applications high performance, are very attractive for applications
with limited space and reducing the need to eliminate because they
have reduced size and volume and can operate in a wide speed range,
without independent ventilation. By using experimental data and
genetic algorithm we have been able to extract values for both the
motor inductance and the electromechanical coupling constant, which
are then compared to measured and/or expected values.
Abstract: The development of allometric models is crucial to
accurate forest biomass/carbon stock assessment. The aim of this
study was to develop a set of biomass prediction models that will
enable the determination of total tree aboveground biomass for
savannah woodland area in Niger State, Nigeria. Based on the data
collected through biometric measurements of 1816 trees and
destructive sampling of 36 trees, five species specific and one site
specific models were developed. The sample size was distributed
equally between the five most dominant species in the study site
(Vitellaria paradoxa, Irvingia gabonensis, Parkia biglobosa,
Anogeissus leiocarpus, Pterocarpus erinaceous). Firstly, the
equations were developed for five individual species. Secondly these
five species were mixed and were used to develop an allometric
equation of mixed species. Overall, there was a strong positive
relationship between total tree biomass and the stem diameter. The
coefficient of determination (R2 values) ranging from 0.93 to 0.99 P
< 0.001 were realised for the models; with considerable low standard
error of the estimates (SEE) which confirms that the total tree above
ground biomass has a significant relationship with the dbh. F-test
values for the biomass prediction models were also significant at p
Abstract: Humans are social mammals, of the primate order.
Our biology, our behaviour and our pathologies are unique to us. In
our desire to understand, reduce solitary confinement one source of
information is the many reports of social isolation of other social
mammals, especially primates. A behavioural study was conducted in
the department of pharmacology at Indira Gandhi Medical College,
Shimla in Himachalpradesh province in India using white albino
mice. Different behavioural parameters were observed by using open
field, tail suspension, tests for aggressive behaviour and social
interactions and the effect of isolation was studied. The results were
evaluated and the standard statistics were applied. The said study was
done to establish facts that isolation itself impairs social behaviour
and can lead to alcohol dependence as well as related drug
dependence.
Abstract: The mixed micellization of adiphenine hydrochloride (ADP) with 1-decyl-3-methylimidazolium chloride (C10mim.Cl), was investigated at different mole fractions and temperatures by surface tension measurements. The synergistic behavior (i.e., non-ideal behavior) for binary mixtures was explained by the deviation of critical micelle concentration (cmc) from ideal critical micelle concentration (cmc*), micellar mole fraction (Xim) from ideal micellar mole fraction (Xiideal), the values of interaction parameter (β) and activity coefficients (fi) (for both mixed micelles and mixed monolayer). The excess free energy (ΔGex) for the ADP- C10mim.Cl binary mixtures explain the stability of mixed micelles in comparison to micelles of pure ADP and C10mim.Cl. Interfacial parameters, i.e., Gibbs surface excess (Гmax), minimum head group area at air/ water
interface (Amin), and free energy of micellization (ΔG0m) were also evaluated for the systems.
Abstract: Today, the pollution due to non-degradable material
such as plastics, has led to studies about the development of
environmental-friendly material. Because of biodegradability
obtained from natural sources, polylactid acid (PLA) and ijuk fiber
are interesting to modify into a composite. This material is also
expected to reduce the impact of environmental pollution. Surface
modification of ijuk fiber through alkalinization with 0.25 M NaOH
solution for 30 minutes was aimed to enhance its compatibility to
PLA, in order to improve properties of the composite such as the
mechanical properties. Alkalinization of the ijuk fibers annihilates
some surface components such as lignin, wax and hemicelloluse, so
the pore on the surface clearly appeared, decreasing of the density
and diameter of the ijuk fibers. The change of the ijuk fiber properties
leads to increase the mechanical properties of PLA composites
reinforced the ijuk fibers through strengthening of the mechanical
interlocking with the PLA matrix. An addition to enhance the
distribution of the fibers in the PLA matrix, the stirring during DCM
solvent evaporation from the mixture of the ijuk fibers and the
dissolved-PLA can reduce amount of the trapped-voids and fibers
pull-out phenomena, which can decrease the mechanical properties of
the composite.
Abstract: The present work analyses different parameters of end
milling to minimize the surface roughness for AISI D2 steel. D2 Steel
is generally used for stamping or forming dies, punches, forming
rolls, knives, slitters, shear blades, tools, scrap choppers, tyre
shredders etc. Surface roughness is one of the main indices that
determines the quality of machined products and is influenced by
various cutting parameters. In machining operations, achieving
desired surface quality by optimization of machining parameters, is a
challenging job. In case of mating components the surface roughness
become more essential and is influenced by the cutting parameters,
because, these quality structures are highly correlated and are
expected to be influenced directly or indirectly by the direct effect of
process parameters or their interactive effects (i.e. on process
environment). In this work, the effects of selected process parameters
on surface roughness and subsequent setting of parameters with the
levels have been accomplished by Taguchi’s parameter design
approach. The experiments have been performed as per the
combination of levels of different process parameters suggested by
L9 orthogonal array. Experimental investigation of the end milling of
AISI D2 steel with carbide tool by varying feed, speed and depth of
cut and the surface roughness has been measured using surface
roughness tester. Analyses of variance have been performed for mean
and signal-to-noise ratio to estimate the contribution of the different
process parameters on the process.
Abstract: This paper presents the results and findings from a
parametric study on the water surface elevation at upstream of bridge
constriction for subcritical flow. In this study, the influence of
Manning's Roughness Coefficient of main channel (nmc) and
floodplain (nfp), and bridge opening (b) flow rate (Q), contraction
(kcon) and expansion coefficients (kexp) were investigated on
backwater level. The DECK bridge models with different span widths
and without any pier were investigated within the two stage channel
having various roughness conditions. One of the most commonly
used commercial one-dimensional HEC-RAS model was used in this
parametric study. This study showed that the effects of main channel
roughness (nmc) and flow rate (Q) on the backwater level are much
higher than those of the floodplain roughness (nfp). Bridge opening
(b) with contraction (kcon) and expansion coefficients (kexp) have very
little effect on the backwater level within this range of parameters.
Abstract: This paper outlines the basic installation and operation of magnetic inductive flow velocity sensors on large underground cooling water pipelines. Research on the effects of cathodic protection as well as into other factors that might influence the overall performance of the meter is presented in this paper. The experiments were carried out on an immersion type magnetic meter specially used for flow measurement of cooling water pipeline. An attempt has been made in this paper to outline guidelines that can ensure accurate measurement related to immersion type magnetic meters on underground pipelines.
Abstract: The turbocharger and turbocharging have been the
inherent component of diesel engines, so that critical parameters of
such engines, as BSFC (Brake Specific Fuel Consumption) or
thermal efficiency, fuel consumption, BMEP (Brake Mean Effective
Pressure), the power density output and emission level have been
improved extensively. In general, the turbocharger can be considered
as the most complex component of diesel engines, because it has
closely interrelated turbomachinery concepts of the turbines and the
compressors to thermodynamic fundamentals of internal combustion
engines and stress analysis of all components.
In this paper, a waste gate for a conventional single stage radial
turbine is investigated by consideration of turbochargers operation
constrains and engine operation conditions, without any detail
designs in the turbine and the compressor. Amount of opening waste
gate which extended between the ranges of full opened and closed
valve, is demonstrated by limiting compressor boost pressure ratio.
Obtaining of an optimum point by regard above mentioned items is
surveyed by three linked meanline modeling programs together
which consist of Turbomatch®, Compal®, Rital® madules in concepts
NREC® respectively.
Abstract: The rhizome of Java grass, Cyperus rotundus was
extracted different organic polar and non-polar solvents and
performed the in vitro antiviral and immunostimulant activities
against White Spot Syndrome Virus (WSSV) and Vibrio harveyi
respectively. Based on the initial screening the ethyl acetate extract of
C. rotundus was strong activities and further it was purified through
silica column chromatography and the fractions were screened again
for antiviral and immunostimulant activity. Among the different
fractions screened against the WSSV and V. harveyi, the fractions, FIII
to FV had strong activities. In order to study the in vivo influence
of C. rotundus, the fractions (F-III to FV) were pooled and delivered
to the F. indicus through artificial feed for 30 days. After the feeding
trail the experimental and control diet fed F. indicus were challenged
with virulent WSSV and studied the survival, molecular diagnosis,
biochemical, haematological, and immunological parameters.
Surprisingly, the pooled fractions (F-IV to FVI) incorporated diets
helped to significantly (P
Abstract: The seismic responses of steel buildings with semirigid
post-tensioned connections (PC) are estimated and compared
with those of steel buildings with typical rigid (welded) connections
(RC). The comparison is made in terms of global and local response
parameters. The results indicate that the seismic responses in terms of
interstory shears, roof displacements, axial load and bending
moments are smaller for the buildings with PC connection. The
difference is larger for global than for local parameters, which in turn
varies from one column location to another. The reason for this
improved behavior is that the buildings with PC dissipate more
hysteretic energy than those with RC. In addition, unlike the case of
buildings with WC, for the PC structures the hysteretic energy is
mostly dissipated at the connections, which implies that structural
damage in beams and columns is not significant. According to these
results, steel buildings with PC are a viable option in high seismicity
areas because of their smaller response and self-centering connection
capacity as well as the fact that brittle failure is avoided.
Abstract: In this paper 3D FEM analysis was carried out on
double lap bonded joint with composite adherents subjected to
dynamic shear. The adherents are made of Carbon/Epoxy while the
adhesive is epoxy Araldite 2031. The maximum average shear stress
and the stress homogeneity in the adhesive layer were examined.
Three fibers textures were considered: UD; 2.5D and 3D with same
volume fiber then a parametric study based on changing the thickness
and the type of fibers texture in 2.5D was accomplished. Moreover,
adherents’ dissimilarity was also investigated. It was found that the
main parameter influencing the behavior is the longitudinal stiffness
of the adherents. An increase in the adherents’ longitudinal stiffness
induces an increase in the maximum average shear stress in the
adhesive layer and an improvement in the shear stress homogeneity
within the joint. No remarkable improvement was observed for
dissimilar adherents.
Abstract: This work introduces a simple device designed to
perform in-situ direct shear and sinkage tests on granular materials
as sand, clays, or regolith. It consists of a box nested within a larger
box. Both have open bottoms, allowing them to be lowered into the
material. Afterwards, two rotating plates on opposite sides of the
outer box will rotate outwards in order to clear regolith on either
side, providing room for the inner box to move relative to the plates
and perform a shear test without the resistance of the surrounding
soil. From this test, Coulomb parameters, including cohesion and
internal friction angle, as well as, Bekker parameters can be inferred.
This device has been designed for a laboratory setting, but with few
modifications, could be put on the underside of a rover for use in
a remote location. The goal behind this work is to ultimately create
a compact, but accurate measuring tool to put onto a rover or any
kind of exploratory vehicle to test for regolith properties of celestial
bodies.