Abstract: This paper is devoted to predict laminar and turbulent
heating rates around blunt re-entry spacecraft at hypersonic
conditions. Heating calculation of a hypersonic body is normally
performed during the critical part of its flight trajectory. The
procedure is of an inverse method, where a shock wave is assumed,
and the body shape that supports this shock, as well as the flowfield
between the shock and body, are calculated. For simplicity the
normal momentum equation is replaced with a second order pressure
relation; this simplification significantly reduces computation time.
The geometries specified in this research, are parabola and ellipsoids
which may have conical after bodies. An excellent agreement is
observed between the results obtained in this paper and those
calculated by others- research. Since this method is much faster than
Navier-Stokes solutions, it can be used in preliminary design,
parametric study of hypersonic vehicles.
Abstract: In this paper we propose a novel Run Time Interface
(RTI) technique to provide an efficient environment for MPI jobs on
the heterogeneous architecture of PARAM Padma. It suggests an
innovative, unified framework for the job management interface
system in parallel and distributed computing. This approach employs
proxy scheme. The implementation shows that the proposed RTI is
highly scalable and stable. Moreover RTI provides the storage access
for the MPI jobs in various operating system platforms and improve
the data access performance through high performance C-DAC
Parallel File System (C-PFS). The performance of the RTI is
evaluated by using the standard HPC benchmark suites and the
simulation results show that the proposed RTI gives good
performance on large scale supercomputing system.
Abstract: A solar powered air heating system using one ended evacuated tubes is experimentally investigated. A solar air heater containing forty evacuated tubes is used for heating purpose. The collector surface area is about 4.44 m2. The length and outer diameters of the outer glass tube and absorber tube are 1500, 47 and 37 mm, respectively. In this experimental setup, we have a header (heat exchanger) of square shape (190 mm x 190 mm). The length of header is 1500 mm. The header consists of a hollow pipe in the center whose diameter is 60 mm through which the air is made to flow. The experimental setup contains approximately 108 liters of water. Water is working as heat collecting medium which collects the solar heat falling on the tubes. This heat is delivered to the air flowing through the header pipe. This heat flow is due to natural convection and conduction. The outlet air temperature depends upon several factors along with air flow rate and solar radiation intensity. The study has been done for both up-flow and down-flow of air in header in similar weather conditions, at different flow rates. In the present investigations the study has been made to find the effect of intensity of solar radiations and flow rate of air on the out let temperature of the air with time and which flow is more efficient. The obtained results show that the system is highly effective for the heating in this region. Moreover, it has been observed that system is highly efficient for the particular flow rate of air. It was also observed that downflow configuration is more effective than up-flow condition at all flow rates due to lesser losses in down-flow. The results show that temperature differences of upper head and lower head, both of water and surface of pipes on the respective ends is lower in down-flow.
Abstract: The effect of autofrettage process in strain hardened
thick-walled pressure vessels has been investigated theoretically by
finite element modeling. Equivalent von Mises stress is used as yield
criterion to evaluate the optimum autofrettage pressure and the
optimum radius of elastic-plastic junction. It has been observed that
the optimum autofrettage pressure increases along with the working
pressure. For two different working pressures, the effect of the ratio
of outer to inner radius (b/a=k) value on the optimum autofrettage
pressure is also noticed. The Optimum autofrettage pressure solely
depends on K value rather than on the inner or outer radius.
Furthermore, percentage reduction of von Mises stresses is compared
for different working pressures and different k values. Maximum von
Mises stress developed at different autofrettage pressure is equated
for elastic perfectly plastic and elastic-plastic material with different
slope of strain hardening segment. Cylinder material having higher
slope of strain hardening segment provides better benedictions in the
autofrettage process.
Abstract: This paper analyzes the effect of a single uniform accounting rule on reporting quality by investigating the influence of IFRS on earnings management. This paper examines whether earnings management is reduced after IFRS adoption through the use of “loss avoidance thresholds”, a method that has been verified in earlier studies. This paper concentrates on two European countries: one that represents the continental code law tradition with weak protection of investors (France) and one that represents the Anglo-American common law tradition, which typically implies a strong enforcement system (the United Kingdom).
The research investigates a sample of 526 companies (6822 firm-year observations) during the years 2000 – 2013. The results are different for the two jurisdictions. This study demonstrates that a single set of accounting standards contributes to better reporting quality and reduces the pervasiveness of earnings management in France. In contrast, there is no evidence that a reduction in earnings management followed the implementation of IFRS in the United Kingdom. Due to the fact that IFRS benefit France but not the United Kingdom, other political and economic factors, such legal system or capital market strength, must play a significant role in influencing the comparability and transparency cross-border companies’ financial statements. Overall, the result suggests that IFRS moderately contribute to the accounting quality of reported financial statements and bring benefit for stakeholders, though the role played by other economic factors cannot be discounted.
Abstract: Service life of existing reinforced concrete (RC)
structures in coastal towns of Sabah has been affected very much.
Concrete crack, spalling of concrete cover and reinforcement rusting
of RC buildings are seen even within 5 years of construction in
Sabah. Hence, in this study a new mix design of concrete grout was
developed using locally available materials and investigated under
two curing conditions and workability, compressive strength,
Accelerated Mortar Bar Test (AMBT), water absorption, volume of
permeable voids (VPV), Sorptivity and 90-days salt ponding test
were conducted. The compressive strength of concrete grout at the
age 90 days was found to be 44.49 N/mm2 under water curing. It was
observed that the percentage of mortar bar length change was below
1% for developed concrete grout. The water absorption of the
concrete grout was in between the range of 0.88 % to 3.60 % under
two different curing up to the age 90 days. It was also observed that
the VPV of concrete was in the range of 0 % to 9.75 and 2.44% to
13.05% under water curing and site curing respectively. It was found
that the Sorptivity of the concrete grout under water curing at the age
of 28 days is 0.211mm/√min and at the age 90 day are 0.067
mm/√min. The chloride content decreased greatly, 90% after a depth
of 15 mm. It was noticed that the site cured samples showed higher
chloride contents near surface compared to water cured samples.
This investigation suggested that the developed mix design of
concrete grout using locally available construction materials can be
used for crack repairing of existing RC structures in Sabah.
Abstract: An important structuring mechanism for knowledge bases is building clusters based on the content of their knowledge objects. The objects are clustered based on the principle of maximizing the intraclass similarity and minimizing the interclass similarity. Clustering can also facilitate taxonomy formation, that is, the organization of observations into a hierarchy of classes that group similar events together. Hierarchical representation allows us to easily manage the complexity of knowledge, to view the knowledge at different levels of details, and to focus our attention on the interesting aspects only. One of such efficient and easy to understand systems is Hierarchical Production rule (HPRs) system. A HPR, a standard production rule augmented with generality and specificity information, is of the following form Decision If < condition> Generality Specificity . HPRs systems are capable of handling taxonomical structures inherent in the knowledge about the real world. In this paper, a set of related HPRs is called a cluster and is represented by a HPR-tree. This paper discusses an algorithm based on cumulative learning scenario for dynamic structuring of clusters. The proposed scheme incrementally incorporates new knowledge into the set of clusters from the previous episodes and also maintains summary of clusters as Synopsis to be used in the future episodes. Examples are given to demonstrate the behaviour of the proposed scheme. The suggested incremental structuring of clusters would be useful in mining data streams.
Abstract: Statistical analysis of electrophysiological recordings
obtained under, e.g. tactile, stimulation frequently suggests participation
in the network dynamics of experimentally unobserved “hidden"
neurons. Such interneurons making synapses to experimentally
recorded neurons may strongly alter their dynamical responses to
the stimuli. We propose a mathematical method that formalizes this
possibility and provides an algorithm for inferring on the presence
and dynamics of hidden neurons based on fitting of the experimental
data to spike trains generated by the network model. The model
makes use of Integrate and Fire neurons “chemically" coupled
through exponentially decaying synaptic currents. We test the method
on simulated data and also provide an example of its application to
the experimental recording from the Dorsal Column Nuclei neurons
of the rat under tactile stimulation of a hind limb.
Abstract: In recent years, response surface methodology (RSM) has
brought many attentions of many quality engineers in different
industries. Most of the published literature on robust design
methodology is basically concerned with optimization of a single
response or quality characteristic which is often most critical to
consumers. For most products, however, quality is multidimensional,
so it is common to observe multiple responses in an experimental
situation. Through this paper interested person will be familiarize
with this methodology via surveying of the most cited technical
papers.
It is believed that the proposed procedure in this study can resolve
a complex parameter design problem with more than two responses.
It can be applied to those areas where there are large data sets and a
number of responses are to be optimized simultaneously. In addition,
the proposed procedure is relatively simple and can be implemented
easily by using ready-made standard statistical packages.
Abstract: This study examined the toxicological effects and
safety of polypeptide k isolated from the seeds of Momordica
charantia in laboratory rats. 30 male Sprague Dawley rats (12 weeks
old, bodyweight 180-200 g) were randomly divided into 3 groups
(1000 mg/kg, 500 mg and 0 mg/kg). Rats were acclimatized to
laboratory conditions for 7 days and at day 8 rats were dosed orally
with polypeptide k (in 2% DMSO/normal saline) and the controls
received the dosed vehicle only. Rats were then observed for 72
hours before sacrificed. Rats were anaesthetized by pentobarbital
(50 mg/kg ip) and 2-3.0 mL of blood was taken by cardiac puncture
and rats were scarified by anaesthetic overdose. Immediately, organs
(heart, lungs, liver, kidneys) were weigh and taken for histology.
Organ sections were then evaluated by a histopathologist. Serum
samples were assayed for liver functions (ALT and γ-GT) and kidney
functions (BUN and creatinine). All rats showed normal behavior
after the dosing and no statistical changes were observed in all blood
parameters and organ weight. Histological examinations revealed
normal organ structures. In conclusion, dosing of rats up to 1000
mg/kg did not have any effects on the rat behavior, liver or kidney
functions nor histology of the selected organs.
Abstract: Unmanned aerial vehicles (UAVs) performing their
operations for a long time have been attracting much attention in
military and civil aviation industries for the past decade. The
applicable field of UAV is changing from the military purpose only to
the civil one. Because of their low operation cost, high reliability and
the necessity of various application areas, numerous development
programs have been initiated around the world. To obtain the optimal
solutions of the design variable (i.e., sectional airfoil profile, wing
taper ratio and sweep) for high performance of UAVs, both the lift and
lift-to-drag ratio are maximized whereas the pitching moment should
be minimized, simultaneously. It is found that the lift force and
lift-to-drag ratio are linearly dependent and a unique and dominant
solution are existed. However, a trade-off phenomenon is observed
between the lift-to-drag ratio and pitching moment. As the result of
optimization, sixty-five (65) non-dominated Pareto individuals at the
cutting edge of design spaces that are decided by airfoil shapes can be
obtained.
Abstract: The issue of classifying objects into one of predefined
groups when the measured variables are mixed with different types
of variables has been part of interest among statisticians in many
years. Some methods for dealing with such situation have been
introduced that include parametric, semi-parametric and nonparametric
approaches. This paper attempts to discuss on a problem
in classifying a data when the number of measured mixed variables is
larger than the size of the sample. A propose idea that integrates a
dimensionality reduction technique via principal component analysis
and a discriminant function based on the location model is discussed.
The study aims in offering practitioners another potential tool in a
classification problem that is possible to be considered when the
observed variables are mixed and too large.
Abstract: Interpolated contour maps drawn for aluminum,
copper and molybdenum in downstream monitoring boreholes of
water dam in Miduk Copper Complex and the values of pH, redox
potential (Eh) and distance from water dam indicate different trends
of variation and behavior of these three elements in downward
groundwater resources. As these maps exhibit, aluminum is dominant
in the most alkaline (pH = 9-11) borehole (MB5) to water dam. The
highest concentration of molybdenum is found in the nearest
borehole (MB6) to water dam. Main concentration of copper is
observed in the most oxidized borehole (MB3 with Eh=293.2mV).
The spatial difference among sampling stations can be attributed to
the existence of faults and diaclases in the geologic structure of
Miduk region which causes the groundwater sampling sites to be
impressed by different contamination sources (toe seepage and upper
seepage water originated from different zones of tailings dump).
Abstract: A method of collecting composition data and examining structural features of pearlite lamellae and the parent austenite at the growth interface in a 13wt. % manganese steel has been demonstrated with the use of Scanning Transmission Electron Microscopy (STEM). The combination of composition data and the structural features observed at the growth interface show that available theories of pearlite growth cannot explain all the observations.
Abstract: Bio-electrical responses obtained from freshwater
sediments by employing microbial fuel cell (MFC) technology were
investigated in this experimental study. During the electricity
generation, organic matter in the sediment was microbially oxidized
under anaerobic conditions with an electrode serving as a terminal
electron acceptor. It was found that the sediment organic matter
(SOM) associated with electrochemically-active electrodes became
more humified, aromatic, and polydispersed, and had a higher average
molecular weight, together with the decrease in the quantity of SOM.
The alteration of characteristics of the SOM was analogous to that
commonly observed in the early stage of SOM diagenetic process (i.e.,
humification). These findings including an elevation of the sediment
redox potential present a possibility of the MFC technology as a new
soil/sediment remediation technique based on its potential benefits:
non-destructive electricity generation and bioremediation.
Abstract: This paper treats a discrete-time finite buffer batch arrival queue with a single working vacation and partial batch rejection in which the inter-arrival and service times are, respectively, arbitrary and geometrically distributed. The queue is analyzed by using the supplementary variable and the imbedded Markov-chain techniques. We obtain steady-state system length distributions at prearrival, arbitrary and outside observer-s observation epochs. We also present probability generation function (p.g.f.) of actual waiting-time distribution in the system and some performance measures.
Abstract: The Constraints imposed by non-thermal
leptogenesis on the survival of the neutrino mass models describing
the presently available neutrino mass patterns, are studied
numerically. We consider the Majorana CP violating phases coming
from right-handed Majorana mass matrices to estimate the baryon
asymmetry of the universe, for different neutrino mass models
namely quasi-degenerate, inverted hierarchical and normal
hierarchical models, with tribimaximal mixings. Considering two
possible diagonal forms of Dirac neutrino mass matrix as either
charged lepton or up-quark mass matrix, the heavy right-handed
mass matrices are constructed from the light neutrino mass matrix.
Only the normal hierarchical model leads to the best predictions of
baryon asymmetry of the universe, consistent with observations in
non-thermal leptogenesis scenario.
Abstract: This article discusses the problem of estimating the
orientation of inclined ground on which a human subject stands based
on information provided by the vestibular system consisting of the
otolith and semicircular canals. It is assumed that body segments are
not necessarily aligned and thus forming an open kinematic chain.
The semicircular canals analogues to a technical gyrometer provide a
measure of the angular velocity whereas the otolith analogues to a
technical accelerometer provide a measure of the translational
acceleration. Two solutions are proposed and discussed. The first is
based on a stand-alone Kalman filter that optimally fuses the two
measurements based on their dynamic characteristics and their noise
properties. In this case, no body dynamic model is needed. In the
second solution, a central extended disturbance observer that
incorporates a body dynamic model (internal model) is employed.
The merits of both solutions are discussed and demonstrated by
experimental and simulation results.
Abstract: Visual information is very important in human perception
of surrounding world. Video is one of the most common ways to
capture visual information. The video capability has many benefits
and can be used in various applications. For the most part, the
video information is used to bring entertainment and help to relax,
moreover, it can improve the quality of life of deaf people. Visual
information is crucial for hearing impaired people, it allows them to
communicate personally, using the sign language; some parts of the
person being spoken to, are more important than others (e.g. hands,
face). Therefore, the information about visually relevant parts of the
image, allows us to design objective metric for this specific case. In
this paper, we present an example of an objective metric based on
human visual attention and detection of salient object in the observed
scene.
Abstract: The efficiency of an image watermarking technique depends on the preservation of visually significant information. This is attained by embedding the watermark transparently with the maximum possible strength. The current paper presents an approach for still image digital watermarking in which the watermark embedding process employs the wavelet transform and incorporates Human Visual System (HVS) characteristics. The sensitivity of a human observer to contrast with respect to spatial frequency is described by the Contrast Sensitivity Function (CSF). The strength of the watermark within the decomposition subbands, which occupy an interval on the spatial frequencies, is adjusted according to this sensitivity. Moreover, the watermark embedding process is carried over the subband coefficients that lie on edges where distortions are less noticeable. The experimental evaluation of the proposed method shows very good results in terms of robustness and transparency.