Abstract: Mercury is a natural occurring element and present in
various concentrations in the environment. Due to its toxic effects, it
is desirable to research mercury sensitive materials to adsorb
mercury. This paper describes the preparation of Au nanoparticles for
mercury adsorption by using a microwave (MW)-polyol method in
the presence of three different Sodium Chloride (NaCl)
concentrations (10, 20 and 30 mM). Mixtures of spherical, triangular,
octahedral, decahedral particles and 1-D product were obtained using
this rapid method. Sizes and shapes was found strongly depend on the
concentrations of NaCl. Without NaCl concentration, spherical,
triangular plates, octahedral, decahedral nanoparticles and 1D
product were produced. At the lower NaCl concentration (10 mM),
spherical, octahedral and decahedral nanoparticles were present,
while spherical and decahedral nanoparticles were preferentially form
by using 20 mM of NaCl concentration. Spherical, triangular plates,
octahedral and decahedral nanoparticles were obtained at the highest
NaCl concentration (30 mM). The amount of mercury adsorbed using
20 ppm mercury solution is the highest (67.5 %) for NaCl
concentration of 30 mM. The high yield of polygonal particles will
increase the mercury adsorption. In addition, the adsorption of
mercury is also due to the sizes of the particles. The sizes of particles
become smaller with increasing NaCl concentrations (size ranges, 5-
16 nm) than those synthesized without addition of NaCl (size ranges
11-32 nm). It is concluded that NaCl concentrations affects the
formation of sizes and shapes of Au nanoparticles thus affects the
mercury adsorption.
Abstract: Earthquakes produce some of the most violent loading
situations that a structure can be subjected to and if a structure fails
under these loads then inevitably human life is put at risk. One of the
most common methods by which a structure fails under seismic
loading is at the connection of structural elements. The research
presented in this paper investigates the interlock systems as a novel
method for building structures. The main objective of this
experimental study wasto determine the dynamic characteristics and
the seismic behaviour of the proposed structures compared to
conventional structural systemsduring seismic motions. Results of
this study indicate that the interlock mechanism of the panels
influences the behaviour of lateral load-resisting systems of the
structures during earthquakes, contributing to better structural
flexibility and easier maintenance.
Abstract: Explosion occurs due to sudden release of energy.
Common examples of explosion include chemical, atomic, heat, and
pressure tank (due to ignition) explosions. Petroleum, gas, and
petrochemical industries operations are threatened by natural risks
and processes. Fires and explosions are the greatest process risks
which cause financial damages.
This study aims at designing a single-floor structure for the control
room of a petroleum refinery to be resistant against gas explosion
loads, and the information related to the structure specifications have
been provided regarding the fact that the structure is made on the
ground's surface. In this research, the lateral stiffness of single pile is
calculated by SPPLN.FOR computer program, and its value for
13624 KN/m single pile has been assessed. The analysis used due to
the loading conditions, is dynamic nonlinear analysis with direct
integration method.
Abstract: This paper attempts to discuss the evolution of the
retrieval techniques focusing on development, challenges and trends
of the image retrieval. It highlights both the already addressed and
outstanding issues. The explosive growth of image data leads to the
need of research and development of Image Retrieval. However,
Image retrieval researches are moving from keyword, to low level
features and to semantic features. Drive towards semantic features is
due to the problem of the keywords which can be very subjective and
time consuming while low level features cannot always describe high
level concepts in the users- mind.
Abstract: Adsorption of methanol and ethanol over mesoporous
siliceous material are studied in the current paper. The pure
mesoporous silica is prepared using tetraethylorthosilicate (TEOS) as
silica source and dodecylamine as template at low pH. The prepared
material was characterized using nitrogen adsorption,nX-ray
diffraction (XRD) and scanning electron microscopy (SEM). The
adsorption kinetics of methanol and ethanol from aqueous solution
were studied over the prepared mesoporous silica material. The
percent removal of alcohol was calculated per unit mass of adsorbent
used. The 1st order model is found to be in agreement with both
adsorbates while the 2nd order model fit the adsorption of methanol
only.
Abstract: Ciprofloxacin (CIP) and Carbamazepine (CBZ), nonbiodegradable pharmaceutical residues, were become emerging pollutants in several aquatic environments. The objectives of this research were to study the possibility to recover these pharmaceuticals residues from pharmaceutical wastewater by increasing the selective adsorption on synthesized functionalized porous silicate, comparing with powdered activated carbon (PAC). Hexagonal mesoporous silicate (HMS), functionalized HMSs (3- aminopropyltriethoxy, 3- mercaptopropyltrimethoxy and noctyldimethyl) were synthesized and characterized physico-chemical characteristics. Obtained adsorption kinetics and isotherms showed that 3-mercaptopropyltrimethoxy functional groups grafted on HMS provided highest CIP and CBZ adsorption capacities; however, it was still lower than that of PAC. The kinetic results were compatible with pseudo-second order. The hydrophobicity and hydrogen bonding might play a key role on the adsorption. Furthermore, the capacities were affected by varying pH values due to the strength of hydrogen bonding between targeted compounds and adsorbents. Electrostatic interaction might not affect the adsorption capacities.
Abstract: Genetic algorithms (GAs) have been widely used for
global optimization problems. The GA performance depends highly
on the choice of the search space for each parameter to be optimized.
Often, this choice is a problem-based experience. The search space
being a set of potential solutions may contain the global optimum
and/or other local optimums. A bad choice of this search space
results in poor solutions. In this paper, our approach consists in
extending the search space boundaries during the GA optimization,
only when it is required. This leads to more diversification of GA
population by new solutions that were not available with fixed search
space boundaries. So, these dynamic search spaces can improve the
GA optimization performances. The proposed approach is applied to
power system stabilizer optimization for multimachine power system
(16-generator and 68-bus). The obtained results are evaluated and
compared with those obtained by ordinary GAs. Eigenvalue analysis
and nonlinear system simulation results show the effectiveness of the
proposed approach to damp out the electromechanical oscillation and
enhance the global system stability.
Abstract: In this paper a polymer electrolyte membrane (PEM)
fuel cell power system including burner, steam reformer, heat
exchanger and water heater has been considered to meet the
electrical, heating, cooling and domestic hot water loads of
residential building which in Tehran. The system uses natural gas as
fuel and works in CHP mode. Design and operating conditions of a
PEM fuel cell system is considered in this study. The energy
requirements of residential building and the number of fuel cell
stacks to meet them have been estimated. The method involved
exergy analysis and entropy generation thorough the months of the
year. Results show that all the energy needs of the building can be
met with 12 fuel cell stacks at a nominal capacity of 8.5 kW. Exergy
analysis of the CHP system shows that the increase in the ambient air
temperature from 1oC to 40oC, will have an increase of entropy
generation by 5.73%.Maximum entropy generates for 15 hour in 15th
of June and 15th of July is estimated to amount at 12624 (kW/K).
Entropy generation of this system through a year is estimated to
amount to 1004.54 GJ/k.year.
Abstract: High pressure adsorption of carbon dioxide on zeolite
13X was investigated in the pressure range (0 to 4) Mpa and
temperatures 298, 308 and 323K. The data fitting is accomplished
with the Toth, UNILAN, Dubinin-Astakhov and virial adsorption
models which are generally used for micro porous adsorbents such as
zeolites. Comparison with experimental data from the literature
indicated that the virial model would best determine results. These
results may be partly attributed to the flexibility of the virial model
which can accommodate as many constants as the data warrants.
Abstract: Nurses in an Armed Force Hospital (AFH) expose to stronger stress than those in a civil hospital, especially in an emergency department (ED). Ironically, stresses of these nurses received few if any attention in academic research in the past. This study collects 227 samples from the emergency departments of four armed force hospitals in central and southern Taiwan. The research indicates that the top five stressors are a massive casualty event, delayed physician support, overloads of routine work, overloads of assignments, and annoying paper work. Excessive work loading was found to be the primary source of stress. Nurses who were perceived to have greater stress levels were more inclined to deploy emotion-oriented approaches and more likely to seek job rotations. Professional stressors and problem-oriented approaches were positively correlated. Unlike other local studies, this study concludes that the excessive work-loading is more stressful in an AFH.
Abstract: Stress analysis of functionally graded composite plates
composed of ceramic, functionally graded material and metal layers is
investigated using 3-D finite element method. In FGM layer, material
properties are assumed to be varied continuously in the thickness
direction according to a simple power law distribution in terms of the
volume fraction of a ceramic and metal. The 3-D finite element model
is adopted by using an 18-node solid element to analyze more
accurately the variation of material properties in the thickness
direction. Numerical results are compared for three types of materials.
In the analysis, the tensile and the compressive stresses are
summarized for various FGM thickness ratios, volume fraction
distributions, geometric parameters and mechanical loads.
Abstract: In this paper, the problem of estimating the optimal
radio capacity of a single-cell spread spectrum (SS) multiple-inputmultiple-
output (MIMO) system operating in a Rayleigh fading environment
is examined. The optimisation between the radio capacity
and the theoretically achievable average channel capacity (in the
sense of information theory) per user of a MIMO single-cell SS system
operating in a Rayleigh fading environment is presented. Then,
the spectral efficiency is estimated in terms of the achievable average
channel capacity per user, during the operation over a broadcast
time-varying link, and leads to a simple novel-closed form expression
for the optimal radio capacity value based on the maximization
of the achieved spectral efficiency. Numerical results are presented to
illustrate the proposed analysis.
Abstract: The accomplished study is based on the appointment
and identification of ageing effects and according to this absorption
of moisture of aircraft cabin components over the life-cycle. In the
first step of the study ceiling panels from same age and from the
same aircraft cabin have been examined according to weight changes
depending on the position in the aircraft cabin. In the second step of
the study different aged ceiling panels have been examined
concerning deflection, weight changes and the acoustic sound
transmission loss. To prove the assumption of water absorption
within the study and with the theoretical background from literature
and scientific papers, an older test panel was exposed extreme
thermal conditions (humidity and temperature) within a climate
chamber to show that there is a general ingress of water to cabin
components and that this ingress of water leads to the change of
different mechanical properties.
Abstract: The design of a gravity dam is performed through an
interactive process involving a preliminary layout of the structure
followed by a stability and stress analysis. This study presents a
method to define the optimal top width of gravity dam with genetic
algorithm. To solve the optimization task (minimize the cost of the
dam), an optimization routine based on genetic algorithms (GAs) was
implemented into an Excel spreadsheet. It was found to perform well
and GA parameters were optimized in a parametric study. Using the
parameters found in the parametric study, the top width of gravity
dam optimization was performed and compared to a gradient-based
optimization method (classic method). The accuracy of the results
was within close proximity. In optimum dam cross section, the ratio
of is dam base to dam height is almost equal to 0.85, and ratio of dam
top width to dam height is almost equal to 0.13. The computerized
methodology may provide the help for computation of the optimal
top width for a wide range of height of a gravity dam.
Abstract: The complex structure of lignocellulose leads to great
difficulties in converting it to fermentable sugars for the ethanol
production. The major hydrolysis impediments are the crystallinity of
cellulose and the lignin content. To improve the efficiency of
enzymatic hydrolysis, microbial pretreatment of corncob was
investigated using two bacterial strains of Bacillus subtilis A 002 and
Cellulomonas sp. TISTR 784 (expected to break open the crystalline
part of cellulose) and lignin-degrading fungus, Phanerochaete
sordida SK7 (expected to remove lignin from lignocellulose). The
microbial pretreatment was carried out with each strain under its
optimum conditions. The pretreated corncob samples were further
hydrolyzed to produce reducing glucose with low amounts of
commercial cellulase (25 U·g-1 corncob) from Aspergillus niger. The
corncob samples were determined for composition change by X-ray
diffraction (XRD), Fourier transform infrared spectroscopy (FTIR),
and scanning electron microscope (SEM). According to the results,
the microbial pretreatment with fungus, P. sordida SK7 was the most
effective for enhancing enzymatic hydrolysis, approximately, 40%
improvement.
Abstract: Low silica type X (LSX) Zeolite is one of useful
material in many manufacturing due to the advantage properties
including high surface area, stability, microporous crystalline
aluminosilicates and positive ion in an extra–framework. The LSX
was used rice husk silica source which obtained by leaching with
hydrochloric acid and calcination at 500 C. To improve the
synthesis method, the LSX was crystallizated in Teflon–lined
autoclave will expedite deceasing of the amorphous particles. The
mixed gel with composition of 5.5 Na2O : 1.65 K2O : Al2O3 : 2.2
SiO2 : 122 H2O was crystallized in different container
(Polypropylene bottom and Teflon–lined autoclave). The obtained
powder was characterized by X–ray diffraction (XRD), X–ray
fluorescence spectrometry, N2 adsorption-desorption analysis BET
surface area Scanning electron microscopy (SEM) and Fourier
transform infrared spectroscopy to justify the quality of zeolite. The
results showed the crystallized zeolite in Teflon lined autoclave has
102.8 nm of crystal size, 286 m2/g of surface area and fewer amounts
of round amorphous particles when compared with the crystallized
zeolite in Polypropylene.
Abstract: Studies on the distribution of traffic demands have
been proceeding by providing traffic information for reducing
greenhouse gases and reinforcing the road's competitiveness in the
transport section, however, since it is preferentially required the
extensive studies on the driver's behavior changing routes and its
influence factors, this study has been developed a discriminant model
for changing routes considering driving conditions including traffic
conditions of roads and driver's preferences for information media. It
is divided into three groups depending on driving conditions in group
classification with the CART analysis, which is statistically
meaningful. And the extent that driving conditions and preferred
media affect a route change is examined through a discriminant
analysis, and it is developed a discriminant model equation to predict a
route change. As a result of building the discriminant model equation,
it is shown that driving conditions affect a route change much more,
the entire discriminant hit ratio is derived as 64.2%, and this
discriminant equation shows high discriminant ability more than a
certain degree.
Abstract: The friction between two metal surfaces results in a
high frequency noise (squealing) which also occurs during the
braking of wagons with rail brakes in the process of shunting at a
marshalling yard with a hump. At that point the noise level may
exceed 130dB, which is extremely unpleasant for workers and
inhabitants. In our research we developed a new composite material
which does not change braking properties, is capable of taking
extremely high pressure loads, reduces noise and is environmentally
friendly. The noise reduction results had been very good and had
shown a decrease of the high frequency noise almost completely (by
99%) at its source. With our technology we had also reduced general
noise by more than 30dBA.
Abstract: Presents a concept for a multidisciplinary process
supporting effective task transitions between different technical
domains during the architectural design stage.
A system configuration challenge is the multifunctional driven
increased solution space. As a consequence, more iteration is needed
to find a global optimum, i.e. a compromise between involved
disciplines without negative impact on development time. Since state
of the art standards like ISO 15288 and VDI 2206 do not provide a
detailed methodology on multidisciplinary design process, higher
uncertainties regarding final specifications arise. This leads to the
need of more detailed and standardized concepts or processes which
could mitigate risks.
The performed work is based on analysis of multidisciplinary
interaction, of modeling and simulation techniques. To demonstrate
and prove the applicability of the presented concept, it is applied to
the design of aircraft high lift systems, in the context of the
engineering disciplines kinematics, actuation, monitoring, installation
and structure design.
Abstract: commercially produced in Malaysia granular
palm shell activated carbon (PSAC) was biomodified with
bacterial biomass (Bacillus subtilis) to produce a hybrid
biosorbent of higher efficiency. The obtained biosorbent was
evaluated in terms of adsorption capacity to remove copper
and zinc metal ions from aqueous solutions. The adsorption
capacity was evaluated in batch adsorption experiments where
concentrations of metal ions varied from 20 to 350 mg/L. A
range of pH from 3 to 6 of aqueous solutions containing metal
ions was tested. Langmuir adsorption model was used to
interpret the experimental data. Comparison of the adsorption
data of the biomodified and original palm shell activated
carbon showed higher uptake of metal ions by the hybrid
biosorbent. A trend in metal ions uptake increase with the
increase in the solution-s pH was observed. The surface
characterization data indicated a decrease in the total surface
area for the hybrid biosorbent; however the uptake of copper
and zinc by it was at least equal to the original PSAC at pH 4
and 5. The highest capacity of the hybrid biosorbent was
observed at pH 5 and comprised 22 mg/g and 19 mg/g for
copper and zinc, respectively. The adsorption capacity at the
lowest pH of 3 was significantly low. The experimental results
facilitated identification of potential factors influencing the
adsorption of copper and zinc onto biomodified and original
palm shell activated carbon.