Abstract: Plate is one of the popular structural elements used in a wide range of industries and structures. They may be subjected to blast loads during explosion events, missile attacks or aircraft attacks. This study is to investigate dynamic responses of the rectangular plate subjected to explosive loads. The effects of material properties and plate thickness on responses of the plate are to be investigated. The compressive pressure is applied to the surface of the plate. Different amounts of thickness in the range from 1mm to 30mm are considered for the plate to evaluate the changes in responses of the plate with respect to plate thickness. Two different properties are considered for the steel. First, the analysis is performed by considering only the elastic-plastic properties for the steel plate. Later on damping is considered to investigate its effects on the responses of the plate. To do analysis, numerical method using a finite element based package ABAQUS is applied. Finally, dynamic responses and graphs showing the relation between maximum displacement of the plate and aim parameters are provided.
Abstract: The seriously damaged structures during earthquakes
show the need and importance of design of reinforced concrete
structures with high ductility. Reinforced concrete beam-column
joints have an important function in all structures. Under seismic
excitation, the beam column joint region is subjected to horizontal
and vertical shear forces whose magnitude is many times higher than
the adjacent beam and column. Strength and ductility of structures
depends mainly on proper detailing of the reinforcement in beamcolumn
joints and the old structures were found ductility deficient.
DSP materials are obtained by using high quantities of super
plasticizers and high volumes of micro silica. In the case of High
Performance Densified Small Particle Concrete (HPDSPC), since
concrete is dense even at the micro-structure level, tensile strain
would be much higher than that of the conventional SFRC, SIFCON
& SIMCON. This in turn will improve cracking behaviour, ductility
and energy absorption capacity of composites in addition to
durability. The fine fibers used in our mix are 0.3mm diameter and 10
mm which can be easily placed with high percentage. These fibers
easily transfer stresses and act as a composite concrete unit to take up
extremely high loads with high compressive strength. HPDSPC
placed in the beam column joints helps in safety of human life due to
prolonged failure.
Abstract: The aim of this study was to investigate the
photocatalytic activity of polycrystalline phases of bismuth tungstate
of formula Bi2WO6. Polycrystalline samples were elaborated using a
coprecipitation technique followed by a calcination process at
different temperatures (300, 400, 600 and 900°C). The obtained
polycrystalline phases have been characterized by X-ray diffraction
(XRD), scanning electron microscopy (SEM), and transmission
electron microscopy (TEM). Crystal cell parameters and cell volume
depend on elaboration temperature. High-resolution electron
microscopy images and image simulations, associated with X-ray
diffraction data, allowed confirming the lattices and space groups
Pca21. The photocatalytic activity of the as-prepared samples was
studied by irradiating aqueous solutions of Rhodamine B, associated
with Bi2WO6 additives having variable crystallite sizes. The
photocatalytic activity of such bismuth tungstates increased as the
crystallite sizes decreased. The high specific area of the
photocatalytic particles obtained at 300°C seems to condition the
degradation kinetics of RhB.
Abstract: Due to the interference effects, the intrinsic
aerodynamic parameters obtained from the individual component
testing are always fundamentally different than those obtained for
complete model testing. Consideration and limitation for such testing
need to be taken into account in any design work related to the
component buildup method. In this paper, the scaled model of a
straight rectangular canard of a hybrid buoyant aircraft is tested at 50
m/s in IIUM-LSWT (Low Speed Wind Tunnel). Model and its
attachment with the balance are kept rigid to have results free from
the aeroelastic distortion. Based on the velocity profile of the test
section’s floor; the height of the model is kept equal to the
corresponding boundary layer displacement. Balance measurements
provide valuable but limited information of overall aerodynamic
behavior of the model. Zero lift coefficient is obtained at -2.2o and
the corresponding drag coefficient was found to be less than that at
zero angle of attack. As a part of the validation of low fidelity tool,
plot of lift coefficient plot was verified by the experimental data and
except the value of zero lift coefficients, the overall trend has under
predicted the lift coefficient. Based on this comparative study, a
correction factor of 1.36 is proposed for lift curve slope obtained
from the panel method.
Abstract: Salinity is one of the major factors limiting crop
production in an arid environment. Despite its global importance
soybean production suffer the problems of salinity stress causing
damages at plant development. So it is implacable to either search for
salinity enhancement of soybean plants. Therefore, in the current
study we try to clarify the mechanism that might be involved in the
ameliorating effects of osmo-protectants such as proline and glycine
betaine as well as, compost application on soybean plants grown
under salinity stress. The experiment was conducted under
greenhouse conditions at the Graduate School of Biosphere Science
Laboratory of Hiroshima University, Japan in 2011. The experiment
was designed as a spilt-split plot based on randomized complete
block design with four replications. The treatments could be
summarized as follows; (i) salinity concentrations (0 and 15 mM), (ii)
compost treatments (0 and 24 t ha-1) and (iii) the exogenous, proline
and glycine betaine concentrations (0 mM and 25 mM) for each.
Results indicated that salinity stress induced reduction in growth and
physiological aspects (dry weight per plant, chlorophyll content, N
and K+ content) of soybean plant compared with those of the
unstressed plants. On the other hand, salinity stress led to increases in
the electrolyte leakage ratio, Na and proline contents. Special
attention was paid to, the tolerance against salt stress was observed,
the improvement of salt tolerance resulted from proline, glycine
betaine and compost were accompanied with improved K+, and
proline accumulation. While, significantly decreased electrolyte
leakage ratio and Na+ content. These results clearly demonstrate that
harmful effect of salinity could reduce on growth aspects of soybean.
Consequently, exogenous osmoprotectants combine with compost
will effectively solve seasonal salinity stress problem and are a good
strategy to increase salinity resistance of soybean in the drylands.
Abstract: This paper presents the modeling approach in SBO
sequence for VVER 1000 reactors and describes the reactor core
behavior at late in-vessel phase in case of late reflooding by HPIS
and gives preliminary results for the ASTECv2 validation. The work
is focused on investigation of plant behavior during total loss of
power and the operator actions. The main goal of these analyses is to
assess the phenomena arising during the Station blackout (SBO)
followed by primary side high pressure injection system (HPIS)
reflooding of already damaged reactor core at very late “in-vessel”
phase. The purpose of the analyses is to define how the later HPIS
switching on can delay the time of vessel failure or possibly avoid
vessel failure. The times for HPP injection were chosen based on
previously performed investigations.
Abstract: One of the fundamental characteristics of Information
and Communication Technology (ICT) has been the ever-changing
nature of continuous release and models of ICTs with its impact on
the academic, social, and psychological benefits of its introduction in
schools. However, there seems to be a growing concern about its
negative impact on students when introduced early in schools for
teaching and learning. This study aims to design a model of child
development factors affecting the early introduction of ICTs in
schools in an attempt to improve the understanding of child
development and introduction of ICTs in schools. The proposed
model is based on a sound theoretical framework. It was designed
following a literature review of child development theories and child
development factors. The child development theoretical framework
that fitted to the best of all child development factors was then chosen
as the basis for the proposed model. This study hence found that the
Jean Piaget cognitive developmental theory is the most adequate
theoretical frameworks for modeling child development factors for
ICT introduction in schools.
Abstract: Damaturu is the capital of Yobe State in northeastern
Nigeria where civic amenities and facilities are not adequate even
after 24 years of its existence. The volatile security and political
situations are most significant causes for the same. The basic facility
for the citizens in terms of drinking water and electricity are not
available. For the drinking water, they have to rely on personal
boreholes or the filtered borehole waters available in packaged
sachets in market. The present study is concerned with environmental
impact of indiscriminate disposal of drinking synthetic polythene
water sachets in Damaturu. The sachet water is popularly called as
“pure water”, but its purity is questionable. Increased production and
consumption of sachet water has led to indiscriminate dumping and
disposal of empty sachets leading to serious environmental threat.
The evidence of this is seen for sachets littering the streets and the
drainages blocked by ‘blocks’ of water sachet waste. Sachet water
gained much popularity in Nigeria because the product is convenient
for use, affordable and economically viable. The present study aims
to find out the solution to this environmental problem. The fieldbased
study has found some significant factors that cause
environmental and socio economic effect due to this. Some
recommendations have been made based on research findings
regarding sustainable waste management, recycling and re-use of the
non-biodegradable products in society.
Abstract: Erosion and abrasion are wear mechanisms reducing
the lifetime of machine elements like valves, pump and pipe systems.
Both wear mechanisms are acting at the same time, causing a
“Synergy” effect, which leads to a rapid damage of the surface.
Different parameters are effective on erosive abrasive wear rate. In
this study effect of particle impact angle on wear rate and wear
mechanism of ductile and brittle materials was investigated. A new
slurry pot was designed for experimental investigation. As abrasive
particle, silica sand was used. Particle size was ranking between 200-
500 μm. All tests were carried out in a sand-water mixture of 20%
concentration for four hours. Impact velocities of the particles were
4.76 m/s. As ductile material steel St 37 with Vickers Hardness
Number (VHN) of 245 and quenched St 37 with 510 VHN was used
as brittle material. After wear tests, morphology of the eroded
surfaces were investigated for better understanding of the wear
mechanisms acting at different impact angles by using Scanning
Electron Microscope. The results indicated that wear rate of ductile
material was higher than brittle material. Maximum wear rate was
observed by ductile material at a particle impact angle of 300 and
decreased further by an increase in attack angle. Maximum wear rate
by brittle materials was by impact angle of 450 and decreased further
up to 900. Ploughing was the dominant wear mechanism by ductile
material. Microcracks on the surface were detected by ductile
materials, which are nucleation centers for crater formation. Number
of craters decreased and depth of craters increased by ductile
materials by attack angle higher than 300. Deformation wear
mechanism was observed by brittle materials. Number and depth of
pits decreased by brittle materials by impact angles higher than 450.
At the end it is concluded that wear rate could not be directly related
to impact angle of particles due to the different reaction of ductile and
brittle materials.
Abstract: When high strength reinforced concrete is exposed to
high temperature due to a fire, deteriorations occur such as loss in
strength and elastic modulus, cracking and spalling of the concrete.
Therefore, it is important to understand risk of structural safety in
building structures by studying structural behaviors and rehabilitation
of fire damaged high strength concrete structures. This paper aims at
investigating rehabilitation effect on fire damaged high strength
concrete beams using experimental and analytical methods. In the
experiments, flexural specimens with high strength concrete are
exposed to high temperatures according to ISO 834 standard time
temperature curve. From four-point loading test, results show that
maximum loads of the rehabilitated beams are similar to or higher than
those of the non-fire damaged RC beam. In addition, structural
analyses are performed using ABAQUS 6.10-3 with same conditions
as experiments to provide accurate predictions on structural and
mechanical behaviors of rehabilitated RC beams. The parameters are
the fire cover thickness and strengths of repairing mortar. Analytical
results show good rehabilitation effects, when the results predicted
from the rehabilitated models are compared to structural behaviors of
the non-damaged RC beams. In this study, fire damaged high strength concrete beams are
rehabilitated using polymeric cement mortar. The predictions from the
finite element (FE) models show good agreements with the
experimental results and the modeling approaches can be used to
investigate applicability of various rehabilitation methods for further
study.
Abstract: Water resource systems modeling has constantly been
a challenge through history for human beings. As the innovative
methodological development is evolving alongside computer sciences
on one hand, researches are likely to confront more complex and
larger water resources systems due to new challenges regarding
increased water demands, climate change and human interventions,
socio-economic concerns, and environment protection and
sustainability. In this research, an automatic calibration scheme has
been applied on the Gilan’s large-scale water resource model using
mathematical programming. The water resource model’s calibration
is developed in order to attune unknown water return flows from
demand sites in the complex Sefidroud irrigation network and other
related areas. The calibration procedure is validated by comparing
several gauged river outflows from the system in the past with model
results. The calibration results are pleasantly reasonable presenting a
rational insight of the system. Subsequently, the unknown optimized
parameters were used in a basin-scale linear optimization model with
the ability to evaluate the system’s performance against a reduced
inflow scenario in future. Results showed an acceptable match
between predicted and observed outflows from the system at selected
hydrometric stations. Moreover, an efficient operating policy was
determined for Sefidroud dam leading to a minimum water shortage
in the reduced inflow scenario.
Abstract: Unsatisfactory experiences due to an information shortage regarding the future pay-offs of actual choices, yield satisficing decision-making. This research will examine, for the first time in the literature, the motivation behind suboptimal decisions due to uncertainty by subjecting Adam Smith’s and Jeremy Bentham’s assumptions about the nature of the actions that lead to satisficing behavior, in order to clarify the theoretical background of a “consumption-based satisfactory time” concept. The contribution of this paper with respect to the existing literature is threefold: firstly, it is showed in this paper that Adam Smith’s uncertainty is related to the problem of the constancy of ideas and not related directly to beliefs. Secondly, possessions, as in Jeremy Bentham’s oeuvre, are assumed to be just as pleasing, as protecting and improving the actual or expected quality of life, so long as they reduce any displeasure due to the undesired outcomes of uncertainty. Finally, each consumption decision incurs its own satisfactory time period, owed to not feeling hungry, being healthy, not having transportation…etc. This reveals that the level of satisfaction is indeed a behavioral phenomenon where its value would depend on the simultaneous satisfaction derived from all activities.
Abstract: It is an indispensible strategy to adopt greenery
approach on architectural bases so as to improve ecological habitats,
decrease heat-island effect, purify air quality, and relieve surface
runoff as well as noise pollution, all of which are done in an attempt to
achieve sustainable environment. How we can do with plant design to
attain the best visual quality and ideal carbon dioxide fixation depends
on whether or not we can appropriately make use of greenery
according to the nature of architectural bases. To achieve the goal, it is
a need that architects and landscape architects should be provided with
sufficient local references. Current greenery studies focus mainly on
the heat-island effect of urban with large scale. Most of the architects
still rely on people with years of expertise regarding the adoption and
disposition of plantation in connection with microclimate scale.
Therefore, environmental design, which integrates science and
aesthetics, requires fundamental research on landscape environment
technology divided from building environment technology. By doing
so, we can create mutual benefits between green building and the
environment. This issue is extremely important for the greening design
of the bases of green buildings in cities and various open spaces. The
purpose of this study is to establish plant selection and allocation
strategies under different building sunshade levels. Initially, with the
shading of sunshine on the greening bases as the starting point, the
effects of the shades produced by different building types on the
greening strategies were analyzed. Then, by measuring the PAR
(photosynthetic active radiation), the relative DLI (daily light integral)
was calculated, while the DLI Map was established in order to
evaluate the effects of the building shading on the established
environmental greening, thereby serving as a reference for plant
selection and allocation. The discussion results were to be applied in
the evaluation of environment greening of greening buildings and
establish the “right plant, right place” design strategy of multi-level
ecological greening for application in urban design and landscape
design development, as well as the greening criteria to feedback to the
eco-city greening buildings.
Abstract: Nowadays, energy dissipation devices are commonly
used in structures. High rate of energy absorption during earthquakes
is the benefit of using such devices, which results in damage
reduction of structural elements, specifically columns. The hysteretic
damping capacity of energy dissipation devices is the key point that it
may adversely make analysis and design process complicated. This
effect may be generally represented by Equivalent Viscous Damping
(EVD). The equivalent viscous damping might be obtained from the
expected hysteretic behavior regarding to the design or maximum
considered displacement of a structure. In this paper, the hysteretic
damping coefficient of a steel Moment Resisting Frame (MRF),
which its performance is enhanced by a Buckling Restrained Brace
(BRB) system has been evaluated. Having foresight of damping
fraction between BRB and MRF is inevitable for seismic design
procedures like Direct Displacement-Based Design (DDBD) method.
This paper presents an approach to calculate the damping fraction for
such systems by carrying out the dynamic nonlinear time history
analysis (NTHA) under harmonic loading, which is tuned to the
natural system frequency. Two MRF structures, one equipped with
BRB and the other without BRB are simultaneously studied.
Extensive analysis shows that proportion of each system damping
fraction may be calculated by its shear story portion. In this way,
contribution of each BRB in the floors and their general contribution
in the structural performance may be clearly recognized, in advance.
Abstract: In this paper numerical studies have been carried out
to examine the pre-ignition flow features of high-performance solid
propellant rocket motors with two different port geometries but with
same propellant loading density. Numerical computations have been
carried out using a validated 3D, unsteady, 2nd-order implicit, SST k-
ω turbulence model. In the numerical study, a fully implicit finite
volume scheme of the compressible, Reynolds-Averaged, Navier-
Stokes equations is employed. We have observed from the numerical
results that in solid rocket motors with highly loaded propellants
having divergent port geometry the hot igniter gases can create preignition
pressure oscillations leading to thrust oscillations due to the
flow unsteadiness and recirculation. We have also observed that the
igniter temperature fluctuations are diminished rapidly thereby
reaching the steady state value faster in the case of solid propellant
rocket motors with convergent port than the divergent port
irrespective of the igniter total pressure. We have concluded that the
prudent selection of the port geometry, without altering the propellant
loading density, for damping the total temperature fluctuations within
the motor is a meaningful objective for the suppression and control of
instability and/or thrust oscillations often observed in solid propellant
rocket motors with non-uniform port geometry.
Abstract: A new design of aerostatic thrust bearing is proposed
for high static stiffness. The bearing body, which is mead of polymer
covered with metallic membrane, is held by a circular ring. Such a
support helps form a concave air gap to grasp the air pressure. The
polymer body, which can be made rapidly by either injection or
molding is able to provide extra damping under dynamic loading. The
smooth membrane not only serves as the bearing surface but also
protects the polymer body. The restrictor is a capillary inside a silicone
tube. It can passively compensate the variation of load by expanding
the capillary diameter for more air flux. In the present example, the
stiffness soars from 15.85 N/μm of typical bearing to 349.85 N/μm at
bearing elevation 9.5 μm; meanwhile the load capacity also enhances
from 346.86 N to 704.18 N.
Abstract: The right to basic sanitation, was elevated to the
category of fundamental right by the Constitution of 1988 to protect
the ecologically balanced environment, ensuring social rights to
health and adequate housing and put the dignity of the human person
as the foundation of the Brazilian Democratic State. Before their
essentiality to humans, this article seeks to understand why universal
access to basic sanitation is a goal so difficult to achieve in Brazil.
Therefore, this research uses the deductive and analytical method.
Given the nature of the research literature, research techniques were
centered in specialized books on the subject, journals, theses and
dissertations, laws, relevant law case and raising social indicators
relating to the theme. The relevance of the topic stems, among other
things, the fact that sanitation services are essential for a dignified
life, i.e., everyone is entitled to the maintenance of the necessary
existence conditions are satisfied. However, the effectiveness of this
right is undermined in society, since Brazil has huge deficit in
sanitation services, denying thus a worthy life to most of the
population. Thus, it can be seen that the provision of water and
sewage services in Brazil is still characterized by a large imbalance,
since the municipalities with lower population index have greater
disability in the sanitation service. The truth is that the precariousness
of water and sewage services in Brazil is still very concentrated in the
North and Northeast regions, limiting the effective implementation of
the Law 11.445/2007 in the country. Therefore, there is urgent need
for a positive service by the State in the provision of sanitation
services in order to prevent and control disease, improve quality of
life and productivity of individuals, besides preventing contamination
of water resources. More than just social and economic necessity,
there is a government duty to implement such services. In this sense,
given the current scenario, to achieve universal access to basic
sanitation imposes many hurdles. These are mainly in the field of
properly formulated and implemented public policies, i.e., it requires
an excellent institutional organization, management services,
strategic planning, social control, in order to provide answers to
complex challenges.
Abstract: These days, the industrial trend is moving away from heavy and bulky passive components to power converter systems that use more and more semiconductor elements. Also, it is difficult to connect the traditional converters to the high and medium voltage. For these reasons, a new family of multilevel inverters has appeared as a solution for working with higher voltage levels. Different modulation topologies like Sinusoidal Pulse Width Modulation (SPWM), Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM) are available for multilevel inverters. In this work, different hybrid modulation techniques which are combination of fundamental frequency modulation and multilevel sinusoidal-modulation are compared. The main characteristic of these modulations are reduction of switching losses with good harmonic performance and balanced power loss dissipation among the device. The proposed hybrid modulation schemes are developed and simulated in Matlab/Simulink for cascaded H-bridge inverter. The results validate the applicability of the proposed schemes for cascaded multilevel inverter.
Abstract: Batch production plants provide a wide range of
scheduling problems. In pharmaceutical industries a batch process
is usually described by a recipe, consisting of an ordering of tasks
to produce the desired product. In this research work we focused
on pharmaceutical production processes requiring the culture of
a microorganism population (i.e. bacteria, yeasts or antibiotics).
Several sources of uncertainty may influence the yield of the culture
processes, including (i) low performance and quality of the cultured
microorganism population or (ii) microbial contamination. For
these reasons, robustness is a valuable property for the considered
application context. In particular, a robust schedule will not collapse
immediately when a cell of microorganisms has to be thrown away
due to a microbial contamination. Indeed, a robust schedule should
change locally in small proportions and the overall performance
measure (i.e. makespan, lateness) should change a little if at all.
In this research work we formulated a constraint programming
optimization (COP) model for the robust planning of antibiotics
production. We developed a discrete-time model with a multi-criteria
objective, ordering the different criteria and performing a
lexicographic optimization. A feasible solution of the proposed
COP model is a schedule of a given set of tasks onto available
resources. The schedule has to satisfy tasks precedence constraints,
resource capacity constraints and time constraints. In particular
time constraints model tasks duedates and resource availability
time windows constraints. To improve the schedule robustness, we
modeled the concept of (a, b) super-solutions, where (a, b) are input
parameters of the COP model. An (a, b) super-solution is one in
which if a variables (i.e. the completion times of a culture tasks)
lose their values (i.e. cultures are contaminated), the solution can be
repaired by assigning these variables values with a new values (i.e.
the completion times of a backup culture tasks) and at most b other
variables (i.e. delaying the completion of at most b other tasks).
The efficiency and applicability of the proposed model is
demonstrated by solving instances taken from a real-life
pharmaceutical company. Computational results showed that
the determined super-solutions are near-optimal.
Abstract: Sewer deposits have been identified as a major cause
of dysfunctions in combined sewer systems regarding sewer
management, which induces different negative consequents resulting
in poor hydraulic conveyance, environmental damages as well as
worker’s health. In order to overcome the problematics of
sedimentation, flushing has been considered as the most operative
and cost-effective way to minimize the sediments impacts and
prevent such challenges. Flushing, by prompting turbulent wave
effects, can modify the bed form depending on the hydraulic
properties and geometrical characteristics of the conduit. So far, the
dynamics of the bed-load during high-flow events in combined sewer
systems as a complex environment is not well understood, mostly due
to lack of measuring devices capable to work in the “hostile” in
combined sewer system correctly. In this regards, a one-episode
flushing issue from an opening gate valve with weir function was
carried out in a trunk sewer in Paris to understand its cleansing
efficiency on the sediments (thickness: 0-30 cm). During more than
1h of flushing within 5 m distance in downstream of this flushing
device, a maximum flowrate and a maximum level of water have
been recorded at 5 m in downstream of the gate as 4.1 m3/s and 2.1
m respectively. This paper is aimed to evaluate the efficiency of this
type of gate for around 1.1 km (from the point -50 m to +1050 m in
downstream from the gate) by (i) determining bed grain-size
distribution and sediments evolution through the sewer channel, as
well as their organic matter content, and (ii) identifying sections that
exhibit more changes in their texture after the flush. For the first one,
two series of sampling were taken from the sewer length and then
analyzed in laboratory, one before flushing and second after, at same
points among the sewer channel. Hence, a non-intrusive sampling
instrument has undertaken to extract the sediments smaller than the
fine gravels. The comparison between sediments texture after the
flush operation and the initial state, revealed the most modified zones
by the flush effect, regarding the sewer invert slope and hydraulic
parameters in the zone up to 400 m from the gate. At this distance,
despite the increase of sediment grain-size rages, D50 (median grainsize)
varies between 0.6 mm and 1.1 mm compared to 0.8 mm and 10
mm before and after flushing, respectively. Overall, regarding the
sewer channel invert slope, results indicate that grains smaller than
sands (< 2 mm) are more transported to downstream along about 400
m from the gate: in average 69% before against 38% after the flush
with more dispersion of grain-sizes distributions. Furthermore, high
effect of the channel bed irregularities on the bed material evolution
has been observed after the flush.