Abstract: Extraction of Fe(III) from aqueous solution using Trin-
butyl Phosphate (TBP) as carrier needs a highly acidic medium
(>6N) as it favours formation of chelating complex FeCl3.TBP.
Similarly, stripping of Iron(III) from loaded organic solvents requires
neutral pH or alkaline medium to dissociate the same complex. It is
observed that TBP co-extracts acids along with metal, which causes
reversal of driving force of extraction and iron(III) is re-extracted
back from the strip phase into the feed phase during Liquid Emulsion
Membrane (LEM) pertraction. Therefore, rate of extraction of
different mineral acids (HCl, HNO3, H2SO4) using TBP with and
without presence of metal Fe(III) was examined. It is revealed that in
presence of metal acid extraction is enhanced. Determination of mass
transfer coefficient of both acid and metal extraction was performed
by using Bulk Liquid Membrane (BLM). The average mass transfer
coefficient was obtained by fitting the derived model equation with
experimentally obtained data. The mass transfer coefficient of the
mineral acid extraction is in the order of kHNO3 = 3.3x10-6m/s > kHCl =
6.05x10-7m/s > kH2SO4 = 1.85x10-7m/s. The distribution equilibria of
the above mentioned acids between aqueous feed solution and a
solution of tri-n-butyl-phosphate (TBP) in organic solvents have been
investigated. The stoichiometry of acid extraction reveals the
formation of TBP.2HCl, HNO3.2TBP, and TBP.H2SO4 complexes.
Moreover, extraction of Iron(III) by TBP in HCl aqueous solution
forms complex FeCl3.TBP.2HCl while in HNO3 medium forms
complex 3FeCl3.TBP.2HNO3
Abstract: Single crystals of Magnesium alloys such as Mg-1Al,
Mg-1Zn-0.5Y, Mg-3Li, and AZ31 alloys were successfully fabricated in this study by employing the modified Bridgman method. Single
crystals of pure Mg were also made in this study. To determine the exact orientation of crystals, Laue back-reflection method and pole figure measurement were carried out on each single crystal. Dimensions of single crystals were 10 mm in diameter and 120 mm in
length. Hardness and compression tests were conducted and the results
revealed that hardness and the strength strongly depended on the
orientation. The closer to basal one the orientation was, the higher hardness and compressive strength were. The effect of alloying was
not higher than that of orientation. After compressive deformation of single crystals, the orientation of the crystals was found to rotate and to be parallel to the basal orientation.
Abstract: System MEMORI automatically detects and recognizes
rotated and/or rescaled versions of the objects of a database within
digital color images with cluttered background. This task is accomplished
by means of a region grouping algorithm guided by heuristic
rules, whose parameters concern some geometrical properties and the
recognition score of the database objects. This paper focuses on the
strategies implemented in MEMORI for the estimation of the heuristic
rule parameters. This estimation, being automatic, makes the system
a self configuring and highly user-friendly tool.
Abstract: Reduced switching loss favours Pulse Skipping
Modulation mode of switching dc-to-dc converters at light loads.
Under certain conditions the converter operates in discontinuous
conduction mode (DCM). Inductor current starts from zero in each
switching cycle as the switching frequency is constant and not
adequately high. A DC-to-DC buck converter is modelled and
simulated in this paper under DCM. Effect of ESR of the filter
capacitor in input current frequency components is studied. The
converter is studied for its operation under input voltage and load
variation. The operating frequency is selected to be close to and
above audio range.
Abstract: Zinc oxide thin films with various microstructures
were grown on substrates by using HCOOH-sols. The reaction
mechanism of the sol system was investigated by performing an XPS
analysis of as-synthesized films, due to the products of hydrolysis
and condensation in the sol system contributing to the chemical state
of the as-synthesized films. The chemical structures of the assynthesized
films related to the microstructures of the final annealed
films were also studied. The results of the Zn 2p3/2, C 1s and O1s
XPS patterns indicate that the hydrolysis reaction in the sol system is
strongly influenced by the HCOOH agent. The results of XRD and
FE-SEM demonstrated the microstructures of the annealed films are
related to the content of hydrolyzed zinc hydrate (Zn-OH) species
present, and that content of the Zn-OH species in the sol system
increases the HCOOH adding, and these Zn-OH species existing in
the sol phase are responsible for large ZnO crystallites in the final
annealed films.
Abstract: During last decades, developing multi-objective
evolutionary algorithms for optimization problems has found
considerable attention. Flexible job shop scheduling problem, as an
important scheduling optimization problem, has found this attention
too. However, most of the multi-objective algorithms that are
developed for this problem use nonprofessional approaches. In
another words, most of them combine their objectives and then solve
multi-objective problem through single objective approaches. Of
course, except some scarce researches that uses Pareto-based
algorithms. Therefore, in this paper, a new Pareto-based algorithm
called controlled elitism non-dominated sorting genetic algorithm
(CENSGA) is proposed for the multi-objective FJSP (MOFJSP). Our
considered objectives are makespan, critical machine work load, and
total work load of machines. The proposed algorithm is also
compared with one the best Pareto-based algorithms of the literature
on some multi-objective criteria, statistically.
Abstract: This article proposes a current-mode square-rooting
circuit using current follower transconductance amplifier (CTFA).
The amplitude of the output current can be electronically controlled
via input bias current with wide input dynamic range. The proposed
circuit consists of only single CFTA. Without any matching
conditions and external passive elements, the circuit is then
appropriate for an IC architecture. The magnitude of the output signal
is temperature-insensitive. The PSpice simulation results are
depicted, and the given results agree well with the theoretical
anticipation. The power consumption is approximately 1.96mW at
±1.5V supply voltages.
Abstract: Nowadays e-Learning is more popular, in Vietnam
especially. In e-learning, materials for studying are very important.
It is necessary to design the knowledge base systems and expert
systems which support for searching, querying, solving of
problems. The ontology, which was called Computational Object
Knowledge Base Ontology (COB-ONT), is a useful tool for
designing knowledge base systems in practice. In this paper, a
design method for knowledge base systems in education using
COKB-ONT will be presented. We also present the design of a
knowledge base system that supports studying knowledge and
solving problems in higher mathematics.
Abstract: The amount and heterogeneity of data in biomedical research, notably in interdisciplinary research, requires new methods for the collection, presentation and analysis of information. Important data from laboratory experiments as well as patient trials are available but come out of distributed resources. The Charite Medical School in Berlin has established together with the German Research Foundation (DFG) a new information service center for kidney diseases and transplantation (Open European Nephrology Science Centre - OpEN.SC). The system is based on a service-oriented architecture (SOA) with main and auxiliary modules arranged in four layers. To improve the reuse and efficient arrangement of the services the functionalities are described as business processes using the standardised Business Process Execution Language (BPEL).
Abstract: This paper presents a narrative management system
for organizations to capture organization's tacit knowledge
through stories. The intention of capturing tacit knowledge is to
address the problem that comes with the mobility of workforce in
organisation. Storytelling in knowledge management context is
seen as a powerful management tool to communicate tacit
knowledge in organization. This narrative management system is
developed firstly to enable uploading of many types of knowledge
sharing stories, from general to work related-specific stories and
secondly, each video has comment functionality where knowledge
users can post comments to other knowledge users. The narrative
management system allows the stories to browse, search and view
by the users. In the system, stories are stored in a video repository.
Stories that were produced from this framework will improve
learning, knowledge transfer facilitation and tacit knowledge
quality in an organization.
Abstract: Our objectives were to evaluate the effects of sire
breed, type of protein supplement, level of supplementation and sex
on wool spinning fineness (SF), its correlations with other wool
characteristics and prediction accuracy in F1 Merino crossbred lambs.
Texel, Coopworth, White Suffolk, East Friesian and Dorset rams
were mated with 500 purebred Merino dams at a ratio of 1:100 in
separate paddocks within a single management system. The F1
progeny were raised on ryegrass pasture until weaning, before forty
lambs were randomly allocated to treatments in a 5 x 2 x 2 x 2
factorial experimental design representing 5 sire breeds, 2
supplementary feeds (canola or lupins), 2 levels of supplementation
(1% or 2% of liveweight) and sex (wethers or ewes). Lambs were
supplemented for six weeks after an initial three weeks of adjustment,
wool sampled at the commencement and conclusion of the feeding
trial and analyzed for SF, mean fibre diameter (FD), coefficient of
variation (CV), standard deviation, comfort factor (CF), fibre
curvature (CURV), and clean fleece yield. Data were analyzed using
mixed linear model procedures with sire fitted as a random effect,
and sire breed, sex, supplementary feed type, level of
supplementation and their second-order interactions as fixed effects.
Sire breed (P
Abstract: Pretreatment is an essential step in the conversion of
lignocellulosic biomass to fermentable sugar that used for biobutanol
production. Among pretreatment processes, microwave is considered
to improve pretreatment efficiency due to its high heating efficiency,
easy operation, and easily to combine with chemical reaction. The
main objectives of this work are to investigate the feasibility of
microwave pretreatment to enhance enzymatic hydrolysis of
corncobs and to determine the optimal conditions using response
surface methodology. Corncobs were pretreated via two-stage
pretreatment in dilute sodium hydroxide (2 %) followed by dilute
sulfuric acid 1 %. Pretreated corncobs were subjected to enzymatic
hydrolysis to produce reducing sugar. Statistical experimental design
was used to optimize pretreatment parameters including temperature,
residence time and solid-to-liquid ratio to achieve the highest amount
of glucose. The results revealed that solid-to-liquid ratio and
temperature had a significant effect on the amount of glucose.
Abstract: This study was a part of the three-year longitudinal
research on setting up an math learning model for the disadvantaged
students in Taiwan. A target 2nd grade class with 10 regular students
and 6 disadvantaged students at a disadvantaged area in Taipei
participated in this study. Two units of a market basal math textbook
concerning fractions, three-dimensional figures, weight and capacity
were adapted to enhance their math learning motivations, confidences
and effects. The findings were (1) curriculum adaptation was effective
on enhancing students- learning motivations, confidences and effects;
(2) story-type problems and illustrations decreased difficulties on
understanding math language for students from new immigrant
families and students with special needs; (3) “concrete –
semiconcrete – abstract" teaching strategies and hands-on activities
were essential to raise students learning interests and effects; and (4)
curriculum adaptation knowledge and skills needed to be included in
the pre- and in-service teacher training programs.
Abstract: One of the most important secrets of succesful companies is the fact that cooperation with NGOs will create a good reputation for them so that they can be immunized to economic crisis. The performance of the most admired companies in the world based on the ratings of Forbes and Fortune show us that most of these firms also have close relationships with their NGOs. Today, if companies do something wrong this information spreads very quickly to do the society. If people do not like the activities of a company, it can find itself in public relations nightmare that can threaten its repuation. Since the cost of communication has dropped dramatically due to the vast use of internet, the increase in communication among stakeholders via internet makes companies more visible. These multiple and interdependent interactions among the network of stakeholders is called as the network relationships. NGOs play the role of catalyst among the stakeholders of a firm to enhance the awareness. Succesful firms are aware of this fact that NGOs have a central role in today-s business world. Firms are also aware of the fact that they can enhance their corporate reputation via cooperation with the NGOs. This fact will be illustrated in this paper by examining some of the actions of the most succesful companies in terms of their cooperations with the NGOs.
Abstract: The ability to predict an accurate temperature
distribution requires the knowledge of the losses, the thermal
characteristics of the materials, and the cooling conditions, all of
which are very difficult to quantify. In this paper, the impact of the
effects of iron and copper losses are investigated separately and
their effects on the heating in various points of the stator of an
induction motor, is highlighted by using two simple tests. In addition,
the effect of a defect, such as an open circuit in a phase of the stator,
on the heating is also obtained by a no-load test.
The squirrel cage induction motor is rated at 2.2 kW; 380 V; 5.2
A; Δ connected; 50 Hz; 1420 rpm and the class of insulation F, has
been thermally tested under several load conditions. Several
thermocouples were placed in strategic points of the stator.
Abstract: The 4G front-end transceiver needs a high
performance which can be obtained mainly with an optimal
architecture and a multi-band Local Oscillator. In this study, we
proposed and presented a new architecture of multi-band frequency
synthesizer based on an Inverse Sine Phase Detector Phase Locked
Loop (ISPD PLL) without any filters and any controlled gain block
and associated with adapted multi band LC tuned VCO using a
several numeric controlled capacitive branches but not binary
weighted. The proposed architecture, based on 0.35μm CMOS
process technology, supporting Multi-band GSM/DCS/DECT/
UMTS/WiMax application and gives a good performances: a phase
noise @1MHz -127dBc and a Factor Of Merit (FOM) @ 1MHz -
186dB and a wide band frequency range (from 0.83GHz to 3.5GHz),
that make the proposed architecture amenable for monolithic
integration and 4G multi-band application.
Abstract: Magnetic carbon nanotubes composites were obtained
by filling carbon nanotubes with paramagnetic iron oxide particles.
Detailed investigation of magnetic behaviour of resulting composites
was done at different temperatures. Measurements indicate that these
functionalized nanotubes are superparamagnetic at room temperature;
however, no superparamagnetism was observed at 125 K and 80 K.
The blocking temperature TB was estimated at 145 K. These magnetic
carbon nanotubes have the potential of being used in a wide range of
applications, in particular, the production of nanofluids, which can be
controlled and steered by appropriate magnetic fields.
Abstract: Knowledge management (KM) is generally
considered to be a positive process in an organisation, facilitating
opportunities to achieve competitive advantage via better quality
information handling, compilation of expert know-how and rapid
response to fluctuations in the business environment. The KM
paradigm as portrayed in the literature informs the processes that can
increase intangible assets so that corporate knowledge is preserved.
However, in some instances, knowledge management exists in a
universe of dynamic tension among the conflicting needs to respect
privacy and intellectual property (IP), to guard against data theft, to
protect national security and to stay within the laws. While the
Knowledge Management literature focuses on the bright side of the
paradigm, there is also a different side in which knowledge is
distorted, suppressed or misappropriated due to personal or
organisational motives (the paradox). This paper describes the ethical
paradoxes that occur within the taxonomy and deontology of
knowledge management and suggests that recognising both the
promises and pitfalls of KM requires wisdom.
Abstract: In this work, a characterization and modeling of
packet loss of a Voice over Internet Protocol (VoIP) communication
is developed. The distributions of the number of consecutive received
and lost packets (namely gap and burst) are modeled from the
transition probabilities of two-state and four-state model.
Measurements show that both models describe adequately the burst
distribution, but the decay of gap distribution for non-homogeneous
losses is better fit by the four-state model. The respective
probabilities of transition between states for each model were
estimated with a proposed algorithm from a set of monitored VoIP
calls in order to obtain representative minimum, maximum and
average values for both models.
Abstract: In this article, we synthesize a novel chitosan -based
superabsorbent hydrogel via graft copolymerization of mixtures
acrylic acid (AA) and N-vinyl pyrollidon onto chitosan backbones.
The polymerization reaction was carried out in an aqueous medium
and in the presence of ammonium persulfate (APS) as an initiator and
N,N'-methylene bisacrylamide (MBA) as a crosslinker.The hydrogel
structures were confirmed by FTIR spectroscopy. The swelling
behavior of these absorbent polymers was also investigated in
various salt solutions. Results indicated that the swelling capacity
decreased with an increase in the ionic strength of the swelling
medium. Furthermore, the swelling of superabsorbing hydrogels was
examined in solutions with pH values ranging between 1.0 and 13.0.
It showed a reversible pH-responsive behavior at pHs 2.0 and 8.0.
This on-off switching behavior makes the synthesized hydrogels as
an excellent candidate for controlled delivery of bioactive agents.