Abstract: Regenerative Thermal Oxidizer (RTO) is one of the
best solutions for removal of Volatile Organic Compounds (VOC)
from industrial processes. In the RTO, VOC in a raw gas are usually
decomposed at 950-1300 K and the combustion heat of VOC is
recovered by regenerative heat exchangers charged with ceramic
honeycombs. The optimization of the treatment of VOC leads to the
reduction of fuel addition to VOC decomposition, the minimization of
CO2 emission and operating cost as well.
In the present work, the thermal efficiency of the RTO was
investigated experimentally in a pilot-scale RTO unit using toluene as
a typical representative of VOC. As a result, it was recognized that the
radiative heat transfer was dominant in the preheating process of a raw
gas when the gas flow rate was relatively low. Further, it was found
that a minimum heat exchanger volume to achieve self combustion of
toluene without additional heating of the RTO by fuel combustion was
dependent on both the flow rate of a raw gas and the concentration of
toluene. The thermal efficiency calculated from fuel consumption and
the decomposed toluene ratio, was found to have a maximum value of
0.95 at a raw gas mass flow rate of 1810 kg·h-1 and honeycombs height
of 1.5m.
Abstract: This paper is a continuation of our interest in the influence of temperature on specific retention volumes and the resulting infinite dilution activity coefficients. This has a direct effect in the design of absorption and stripping columns for the abatement of volatile organic compounds. The interaction of 13 volatile organic compounds (VOCs) with polydimethylsiloxane (PDMS) at varying temperatures was studied by gas liquid chromatography (GLC). Infinite dilution activity coefficients and specific retention volumes obtained in this study were found to be in agreement with those obtained from static headspace and group contribution methods by the authors as well as literature values for similar systems. Temperature variation also allows for transport calculations for different seasons. The results of this work confirm that PDMS is well suited for the scrubbing of VOCs from waste gas streams. Plots of specific retention volumes against temperature gave linear van-t Hoff plots.
Abstract: Losses reduction initiatives in distribution systems
have been activated due to the increasing cost of supplying
electricity, the shortage in fuel with ever-increasing cost to produce
more power, and the global warming concerns. These initiatives have
been introduced to the utilities in shape of incentives and penalties.
Recently, the electricity distribution companies in Oman have been
incentivized to reduce the distribution technical and non-technical
losses with an equal annual reduction rate for 6 years. In this paper,
different techniques for losses reduction in Mazoon Electricity
Company (MZEC) are addressed. In this company, high numbers of
substation and feeders were found to be non-compliant with the
Distribution System Security Standard (DSSS). Therefore, 33
projects have been suggested to bring non-complying 29 substations
and 28 feeders to meet the planed criteria and to comply with the
DSSS. The largest part of MZEC-s network (South Batinah region)
was modeled by ETAP software package. The model has been
extended to implement the proposed projects and to examine their
effects on losses reduction. Simulation results have shown that the
implementation of these projects leads to a significant improvement
in voltage profile, and reduction in the active and the reactive power
losses. Finally, the economical analysis has revealed that the
implementation of the proposed projects in MZEC leads to an annual
saving of about US$ 5 million.
Abstract: The link between coordinate transformations in the plane and their effects on the graph of a function can be difficult for students studying college level mathematics to comprehend. To solidify this conceptual link in the mind of a student Microsoft Excel can serve as a convenient graphing tool and pedagogical aid. The authors of this paper describe how various transformations and their related functional symmetry properties can be graphically displayed with an Excel spreadsheet.
Abstract: Personal computers draw non-sinusoidal current
with odd harmonics more significantly. Power Quality of
distribution networks is severely affected due to the flow of these
generated harmonics during the operation of electronic loads. In
this paper, mathematical modeling of odd harmonics in current like
3rd, 5th, 7th and 9th influencing the power quality has been presented.
Live signals have been captured with the help of power quality
analyzer for analysis purpose. The interesting feature is that Total
Harmonic Distortion (THD) in current decreases with the increase
of nonlinear loads has been verified theoretically. The results
obtained using mathematical expressions have been compared with
the practical results and exciting results have been found.
Abstract: The use of machine vision to inspect the outcome of
surgical tasks is investigated, with the aim of incorporating this
approach in robotic surgery systems. Machine vision is a non-contact
form of inspection i.e. no part of the vision system is in direct contact
with the patient, and is therefore well suited for surgery where
sterility is an important consideration,. As a proof-of-concept, three
primary surgical tasks for a common neurosurgical procedure were
inspected using machine vision. Experiments were performed on
cadaveric pig heads to simulate the two possible outcomes i.e.
satisfactory or unsatisfactory, for tasks involved in making a burr
hole, namely incision, retraction, and drilling. We identify low level
image features to distinguish the two outcomes, as well as report on
results that validate our proposed approach. The potential of using
machine vision in a surgical environment, and the challenges that
must be addressed, are identified and discussed.
Abstract: This paper presents a numerical analysis of the
seismic behaviour of earth dams. Analysis is conducted for the solid
phase. It may correspond to the response of the dam before water
filling. Analysis is conducted for a simple case which concerns the
elastic response of the dam. Numerical analyses are conducted using
the FLAC3D program. The behaviour of the Shell and core of the
dam and the foundation behaviour is assumed to be elastic. Result
shows the influence of the variation of the shear modulus of the core
and shell on the seismic amplification of the dam. It can be observed
that the variation of the shearing modulus of the core leads to a
moderate increase in the dynamic amplification and the increase in
the shell shearing modulus leads to a significant increase in the
dynamic amplification.
Abstract: Aerial and satellite images are information rich. They are also complex to analyze. For GIS systems, many features require fast and reliable extraction of roads and intersections. In this paper, we study efficient and reliable automatic extraction algorithms to address some difficult issues that are commonly seen in high resolution aerial and satellite images, nonetheless not well addressed in existing solutions, such as blurring, broken or missing road boundaries, lack of road profiles, heavy shadows, and interfering surrounding objects. The new scheme is based on a new method, namely reference circle, to properly identify the pixels that belong to the same road and use this information to recover the whole road network. This feature is invariable to the shape and direction of roads and tolerates heavy noise and disturbances. Road extraction based on reference circles is much more noise tolerant and flexible than the previous edge-detection based algorithms. The scheme is able to extract roads reliably from images with complex contents and heavy obstructions, such as the high resolution aerial/satellite images available from Google maps.
Abstract: In the present work, we have developed a symmetric electrochemical capacitor based on the nanostructured iron oxide (Fe3O4)-activated carbon (AC) nanocomposite materials. The physical properties of the nanocomposites were characterized by Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The electrochemical performances of the composite electrode in 1.0 M Na2SO3 and 1.0 M Na2SO4 aqueous solutions were evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The composite electrode with 4 wt% of iron oxide nanomaterials exhibits the highest capacitance of 86 F/g. The experimental results clearly indicate that the incorporation of iron oxide nanomaterials at low concentration to the composite can improve the capacitive performance, mainly attributed to the contribution of the pseudocapacitance charge storage mechanism and the enhancement on the effective surface area of the electrode. Nevertheless, there is an optimum threshold on the amount of iron oxide that needs to be incorporated into the composite system. When this optimum threshold is exceeded, the capacitive performance of the electrode starts to deteriorate, as a result of the undesired particle aggregation, which is clearly indicated in the SEM analysis. The electrochemical performance of the composite electrode is found to be superior when Na2SO3 is used as the electrolyte, if compared to the Na2SO4 solution. It is believed that Fe3O4 nanoparticles can provide favourable surface adsorption sites for sulphite (SO3 2-) anions which act as catalysts for subsequent redox and intercalation reactions.
Abstract: This study carried out to determine the effect of plant
densities on some agronomic characteristics of four safflower cultivars in spring planting. The experiment was conducted at Yazd,
Iran- using a factorial in a randomized complete block design with four replications. Cultivars were including Arak, IL, Asteria and Local and plant densities were 10, 13.3, 20 and 40 plant/m2. Number
of seeds/head, number of heads/plant, HI, 1000-seed weight and seed yield significantly decreased as planting density increased. With increasing planting density, LAI, plant height, first branch height and
biological yield increased. The highest seed yield was obtained in 13.3 plant/m2 (2167 kg/ha). There were significant differences
between cultivars. Local cv. had higher seed yield than the other cultivars mainly due to higher heads/plant and seeds/head.
Abstract: Empirical force fields and density functional theory
(DFT) was used to study the binding energies and structures of
methylamine on the surface of activated carbons (ACs). This is a first
step in studying the adsorption of alkyl amines on the surface of
functionalized ACs. The force fields used were Dreiding (DFF),
Universal (UFF) and Compass (CFF) models. The generalized
gradient approximation with Perdew Wang 91 (PW91) functional
was used for DFT calculations. In addition to obtaining the aminecarboxylic
acid adsorption energies, the results were used to establish
reliability of the empirical models for these systems. CFF predicted a
binding energy of -9.227 (kcal/mol) which agreed with PW91 at -
13.17 (kcal/mol), compared to DFF 0 (kcal/mol) and UFF -0.72
(kcal/mol). However, the CFF binding energies for the amine to ester
and ketone disagreed with PW91 results. The structures obtained
from all models agreed with PW91 results.
Abstract: High strength concrete (HSC) provides high strength
but lower ductility than normal strength concrete. This low ductility
limits the benefit of using HSC in building safe structures. On the
other hand, when designing reinforced concrete beams, designers
have to limit the amount of tensile reinforcement to prevent the
brittle failure of concrete. Therefore the full potential of the use of
steel reinforcement can not be achieved. This paper presents the idea
of confining concrete in the compression zone so that the HSC will
be in a state of triaxial compression, which leads to improvements in
strength and ductility. Five beams made of HSC were cast and tested.
The cross section of the beams was 200×300 mm, with a length of 4
m and a clear span of 3.6 m subjected to four-point loading, with
emphasis placed on the midspan deflection. The first beam served as
a reference beam. The remaining beams had different tensile
reinforcement and the confinement shapes were changed to gauge
their effectiveness in improving the strength and ductility of the
beams. The compressive strength of the concrete was 85 MPa and the
tensile strength of the steel was 500 MPa and for the stirrups and
helixes was 250 MPa. Results of testing the five beams proved that
placing helixes with different diameters as a variable parameter in the
compression zone of reinforced concrete beams improve their
strength and ductility.
Abstract: Heuristics-based search methodologies normally
work on searching a problem space of possible solutions toward
finding a “satisfactory" solution based on “hints" estimated from the
problem-specific knowledge. Research communities use different
types of methodologies. Unfortunately, most of the times, these hints
are immature and can lead toward hindering these methodologies by
a premature convergence. This is due to a decrease of diversity in
search space that leads to a total implosion and ultimately fitness
stagnation of the population. In this paper, a novel Decision Maturity
framework (DMF) is introduced as a solution to this problem. The
framework simply improves the decision on the direction of the
search by materializing hints enough before using them. Ideas from
this framework are injected into the particle swarm optimization
methodology. Results were obtained under both static and dynamic
environment. The results show that decision maturity prevents
premature converges to a high degree.
Abstract: A wireless power transfer system can attribute to the
fields in robot, aviation and space in which lightening the weight of
device and improving the movement play an important role. A
wireless power transfer system was investigated to overcome the
inconvenience of using power cable. Especially a wireless power
transfer technology is important element for mobile robots. We
proposed the wireless power transfer system of the half-bridge
resonant converter with the frequency tracking and optimized
power transfer control unit. And the possibility of the application
and development system was verified through the experiment with
LED loads.
Abstract: The lubricating properties of commercially available
mucins originating from different animal organs, namely bovine
submaxillary mucin (BSM) and porcine gastric mucin (PGM), have
been characterized at polymeric surfaces for biomedical applications.
Atomic force microscopy (AFM) and pin-on-disk tribometry have
been employed for tribological studies at nanoscale and macroscale
contacts, respectively. Polystyrene (PS) was employed to represent
‘rigid’ contacts, whereas poly(dimethylsiloxane) (PDMS) was
employed to represent ‘soft contacts’. To understand the lubricating
properties of mucins in correlation with the coverage on surfaces,
adsorption properties of mucins onto the polymeric substrates have
been characterized by means of optical waveguide light-mode
spectroscopy (OWLS). Both mucins showed facile adsorption onto
both polymeric substrates, but the lubricity was highly dependent
upon the pH change between 2 and 7.
Abstract: To maximise furnace production it-s necessary to
optimise furnace control, with the objectives of achieving maximum
power input into the melting process, minimum network distortion
and power-off time, without compromise on quality and safety. This
can be achieved with on the one hand by an appropriate electrode
control and on the other hand by a minimum of AC transformer
switching.
Electrical arc is a stochastic process; witch is the principal cause
of power quality problems, including voltages dips, harmonic
distortion, unbalance loads and flicker. So it is difficult to make an
appropriate model for an Electrical Arc Furnace (EAF). The factors
that effect EAF operation are the melting or refining materials,
melting stage, electrode position (arc length), electrode arm control
and short circuit power of the feeder. So arc voltages, current and
power are defined as a nonlinear function of the arc length. In this
article we propose our own empirical function of the EAF and model,
for the mean stages of the melting process, thanks to the
measurements in the steel factory.
Abstract: A two-dimensional numerical simulation of the contribution
of both inertial and aerodynamic forces on the blade loads of
a Vertical-Axis Wind Turbine (VAWT) is presented. After describing
the computational model and the relative validation procedure, a
complete campaign of simulations - based on full RANS unsteady
calculations - is proposed for a three-bladed rotor architecture characterized
by a NACA 0021 airfoil. For each analyzed angular velocity,
the combined effect of pressure and viscous forces acting on every
rotor blade are compared to the corresponding centrifugal forces,
due to the revolution of the turbine, thus achieving a preliminary
estimation of the correlation between overall rotor efficiency and
structural blade loads.
Abstract: Market based models are frequently used in the resource
allocation on the computational grid. However, as the size of
the grid grows, it becomes difficult for the customer to negotiate
directly with all the providers. Middle agents are introduced to
mediate between the providers and customers and facilitate the
resource allocation process. The most frequently deployed middle
agents are the matchmakers and the brokers. The matchmaking agent
finds possible candidate providers who can satisfy the requirements
of the consumers, after which the customer directly negotiates with
the candidates. The broker agents are mediating the negotiation with
the providers in real time.
In this paper we present a new type of middle agent, the marketmaker.
Its operation is based on two parallel operations - through
the investment process the marketmaker is acquiring resources and
resource reservations in large quantities, while through the resale process
it sells them to the customers. The operation of the marketmaker
is based on the fact that through its global view of the grid it can
perform a more efficient resource allocation than the one possible in
one-to-one negotiations between the customers and providers.
We present the operation and algorithms governing the operation
of the marketmaker agent, contrasting it with the matchmaker and
broker agents. Through a series of simulations in the task oriented
domain we compare the operation of the three agents types. We find
that the use of marketmaker agent leads to a better performance in the
allocation of large tasks and a significant reduction of the messaging
overhead.
Abstract: The production of activated carbon from low or zero cost of agricultural by-products or wastes has received great attention from academics and practitioners due to its economic and environmental benefits. In the production of bamboo furniture, a significant amount of bamboo waste is inevitably generated. Therefore, this research aimed to prepare activated carbons from bamboo furniture waste by chemical (KOH) activation and determine their properties and adsorption capacities for water treatment. The influence of carbonization time on the properties and adsorption capacities of activated carbons was also investigated. The finding showed that the bamboo-derived activated carbons had microporous characteristics. They exhibited high tendency for the reduction of impurities present in effluent water. Their adsorption capacities were comparable to the adsorption capacity of a commercial activated carbon regarding to the reduction in COD, TDS and turbidity of the effluent water.
Abstract: Mercury adsorption on soil was investigated at
different ionic strengths using Ca(NO3)2 as a background electrolyte.
Results fitted the Langmuir equation and the adsorption isotherms
reached a plateau at higher equilibrium concentrations. Increasing
ionic strength decreased the sorption of mercury, due to the
competition of Ca ions for the sorption sites in the soils. The
influence of ionic strength was related to the mechanisms of heavy
metal sorption by the soil. These results can be of practical
importance both in the agriculture and contaminated soils since the
solubility of mercury in soils are strictly dependent on the adsorption
and release process.