Abstract: A cold, thin film of liquid impinging on an isothermal
hot, horizontal surface has been investigated. An approximate
solution for the velocity and temperature distributions in the flow
along the horizontal surface is developed, which exploits the
hydrodynamic similarity solution for thin film flow. The approximate
solution may provide a valuable basis for assessing flow and heat
transfer in more complex settings.
Abstract: This paper presents dynamic models of distributed
generators (DG) and investigates dynamic behavior of the DG units
in the micro grid system. The DG units include photovoltaic and fuel
cell sources. The voltage source inverter is adopted since the
electronic interface which can be equipped with its controller to keep
stability of the micro grid during small signal dynamics. This paper
also introduces power management strategies and implements the DG
load sharing concept to keep the micro grid operation in gridconnected
and islanding modes of operation. The results demonstrate
the operation and performance of the photovoltaic and fuel cell as
distributed generators in a micro grid. The entire control system in
the micro grid is developed by combining the benefits of the power
control and the voltage control strategies. Simulation results are all
reported, confirming the validity of the proposed control technique.
Abstract: Honeys are produced by Apis mellifera and stingless
bees (Meliponini) in Ecuador. We studied honey produced in
beeswax combs by Apis mellifera, and honey produced in pots by
Geotrigona and Scaptotrigona bees. Chloroform extracts of honey
were obtained for fast NMR spectra. The 1D spectra were acquired at
298 K, with a 600 MHz NMR Bruker instrument, using a modified
double pulsed field gradient spin echoes (DPFGSE) sequence.
Signals of 1H NMR spectra were integrated and used as inputs for
PCA, PLS-DA analysis, and labelled sets of classes were successfully
identified, enhancing the separation between the three groups of
honey according to the entomological origin: A. mellifera,
Geotrigona and Scaptotrigona. This procedure is therefore
recommended for authenticity test of honey in Ecuador.
Abstract: This paper deals with the theoretical and numerical
investigation of magneto hydrodynamic boundary layer flow of a
nanofluid past a wedge shaped wick in heat pipe used for the cooling
of electronic components and different type of machines. To
incorporate the effect of nanoparticle diameter, concentration of
nanoparticles in the pure fluid, nanothermal layer formed around the
nanoparticle and Brownian motion of nanoparticles etc., appropriate
models are used for the effective thermal and physical properties of
nanofluids. To model the rotation of nanoparticles inside the base
fluid, microfluidics theory is used. In this investigation ethylene
glycol (EG) based nanofluids, are taken into account. The non-linear
equations governing the flow and heat transfer are solved by using a
very effective particle swarm optimization technique along with
Runge-Kutta method. The values of heat transfer coefficient are
found for different parameters involved in the formulation viz.
nanoparticle concentration, nanoparticle size, magnetic field and
wedge angle etc. It is found that, the wedge angle, presence of
magnetic field, nanoparticle size and nanoparticle concentration etc.
have prominent effects on fluid flow and heat transfer characteristics
for the considered configuration.
Abstract: By textile science incorporating with electronic
industry, developed textile products start to take part in different
areas such as industry, military, space, medical etc. for health,
protection, defense, communication and automation. Electronic
textiles (e-textiles) are fabrics that contain electronics and
interconnections with them. In this study, two types of base yarns
(cotton and acrylic) and three types of conductive steel yarns with
different linear resistance values (14Ω/m, 30Ω/m, 70Ω/m) were used
to investigate the effect of base yarn type and linear resistance of
conductive yarns on thermal behavior of e-textile structures. Thermal
behavior of samples was examined by thermal camera.
Abstract: Control of honey frauds is needed in Ecuador to
protect bee keepers and consumers because simple syrups and new
syrups with eucalyptus are sold as genuine honeys. Authenticity of
Ecuadorian commercial honeys was tested with a vortex emulsion
consisting on one volume of honey:water (1:1) dilution, and two
volumes of diethyl ether. This method allows a separation of phases
in one minute to discriminate genuine honeys that form three phase
and fake honeys that form two phases; 34 of the 42 honeys analyzed
from five provinces of Ecuador were genuine. This was confirmed
with 1H NMR spectra of honey dilutions in deuterated water with an
enhanced amino acid region with signals for proline, phenylalanine
and tyrosine. Classic quality indicators were also tested with this
method (sugars, HMF), indicators of fermentation (ethanol, acetic
acid), and residues of citric acid used in the syrup manufacture. One
of the honeys gave a false positive for genuine, being an admixture of
genuine honey with added syrup, evident for the high sucrose.
Sensory analysis was the final confirmation to recognize the honey
groups studied here, namely honey produced in combs by Apis
mellifera, fake honey, and honey produced in cerumen pots by
Geotrigona, Melipona, and Scaptotrigona. Chloroform extractions of
honey were also done to search lipophilic additives in NMR spectra.
This is a valuable contribution to protect honey consumers, and to
develop the beekeeping industry in Ecuador.
Abstract: This paper presents a study the effect of nose radius
(Rz-mm) on cutting force components and temperatures during the
machining simulation in an orthogonal cutting process for titanium
alloy (Ti-6Al-4V). The cutting process was performed at various
nose radiuses (Rz-mm) while the depth of cut (d-mm), feed rate (fmm/
tooth) and cutting speed (vc-m/ min) were remained constant.
The main cutting force (Fc), feed cutting force (Ft) and temperatures
were estimated by using finite element modeling (FEM) through
ABAQUS/EXPLICIT software and the simulation was developed the
two-dimension via an orthogonal cutting process during machining
titanium alloy (Ti-6Al-4V). The results led to the conclusion that the
nose radius (Rz-mm) has affected directly on the cutting force
components. However, temperature gave no indication or has no
significant relation with nose radius during machining titanium alloy
(Ti-6Al-4V). Hence, any increase or decrease in the nose radius (Rzmm)
during machining operation led to effect on the cutting forces
and thus it will be effective on surface finish, quality, and quantity of
products.
Abstract: In emerging economies, recycling is an opportunity
for the cities to increase the lifespan of sanitary landfills, reduce the
costs of the solid waste management, decrease the environmental
problems of the waste treatment through reincorporate waste in the
productive cycle and protect and develop people’s livelihoods of
informal waste pickers. However, few studies have analysed the
possibilities and strategies to integrate formal and informal sectors in
the solid waste management for the benefit of both. This study seek
to make a strength, weakness, opportunity, and threat (SWOT)
analysis in three recycling associations of Bogotá with the aim to
understand and determine the situation of recycling from perspective
of informal sector in its transition to enter as authorized waste
providers. Data used in the analysis are derived from multiple
strategies such as literature review, the Bogota’s recycling database,
focus group meetings, governmental reports, national laws and
regulations and specific interviews with key stakeholders. Results of
this study show as the main stakeholders of formal and informal
sector of waste management can identify the internal and internal
conditions of recycling in Bogotá. Several strategies were designed
based on the SWOTs determined, could be useful for Bogotá to
advance and promote recycling as a key strategy for integrated
sustainable waste management in the city.
Abstract: An innovative flooring underlayment was produced
and tested. The composite system is made of common OSB boards
and a layer of eco-friendly non-cement gypsum based material
(GeoGypTM). It was found that the shear bond between the two
materials is sufficient to secure the composite interaction between the
two. The very high compressive strength and relatively high tensile
strength of the non-cement based component together with its high
modulus of elasticity provides enough strength and stiffness for the
composite product to cover wider spacing between the joists. The
initial findings of this study indicate that with joist spacing as wide as
800 mm, the flooring system provides enough strength without
compromising the serviceability requirements of the building codes.
Abstract: This paper is concerned with knowledge representation
and extraction of fuzzy if-then rules using Interval Type-2
Context-based Fuzzy C-Means clustering (IT2-CFCM) with the aid of
fuzzy granulation. This proposed clustering algorithm is based on
information granulation in the form of IT2 based Fuzzy C-Means
(IT2-FCM) clustering and estimates the cluster centers by preserving
the homogeneity between the clustered patterns from the IT2 contexts
produced in the output space. Furthermore, we can obtain the
automatic knowledge representation in the design of Radial Basis
Function Networks (RBFN), Linguistic Model (LM), and Adaptive
Neuro-Fuzzy Networks (ANFN) from the numerical input-output data
pairs. We shall focus on a design of ANFN in this paper. The
experimental results on an estimation problem of energy performance
reveal that the proposed method showed a good knowledge
representation and performance in comparison with the previous
works.
Abstract: This paper presents a part of the project solving which
is dedicated to the identification of the hazardous waste with the most
critical production within the Czech Republic with the aim to study
and find the optimal composition of the cement matrix that will
ensure maximum content disposal of chosen hazardous waste. In the
first stage of project solving – which represents this paper – a specific
hazardous waste was chosen, its properties were identified and
suitable solidification agents were chosen. Consequently
solidification formulas and testing methodology was proposed.
Abstract: Reliability of long-term storage products is related to
the availability of the whole system, and the evaluation of storage life
is of great necessity. These products are usually highly reliable and
little failure information can be collected. In this paper, an analytical
method based on data from accelerated storage life test is proposed to
evaluate the reliability index of the long-term storage products. Firstly,
singularities are eliminated by data normalization and residual
analysis. Secondly, with the preprocessed data, the degradation path
model is built to obtain the pseudo life values. Then by life distribution
hypothesis, we can get the estimator of parameters in high stress levels
and verify failure mechanism consistency. Finally, the life distribution
under the normal stress level is extrapolated via the acceleration model
and evaluation of the actual average life is available. An application
example with the camera stabilization device is provided to illustrate
the methodology we proposed.
Abstract: This paper presents a model for a modified T-junction
device for microspheres generation. The numerical model is
developed using a commercial software package: COMSOL
Multiphysics. In order to test the accuracy of the numerical model,
multiple variables, such as the flow rate of cross-flow, fluid properties,
structure, and geometry of the microdevice are applied. The results
from the model are compared with the experimental results in the
diameter of the microsphere generated. The comparison shows a good
agreement. Therefore the model is useful in further optimization of the
device and feedback control of microsphere generation if any.
Abstract: The capability of exploiting the electronic charge and
spin properties simultaneously in a single material has made diluted
magnetic semiconductors (DMS) remarkable in the field of
spintronics. We report the designing of DMS based on zinc-blend
ZnO doped with Cr impurity. The full potential linearized augmented
plane wave plus local orbital FP-L(APW+lo) method in density
functional theory (DFT) has been adapted to carry out these
investigations. For treatment of exchange and correlation energy,
generalized gradient approximations have been used. Introducing Cr
atoms in the matrix of ZnO has induced strong magnetic moment
with ferromagnetic ordering at stable ground state. Cr:ZnO was found
to favor the short range magnetic interaction that
reflect tendency of Cr clustering. The electronic structure of ZnO is
strongly influenced in the presence of Cr impurity atoms where
impurity bands appear in the band gap.
Abstract: This study investigates the suitability of using plastic,
such as polyethylene terephthalate (PET), as a partial replacement of
natural coarse and fine aggregates (for example, brick chips and
natural sand) to produce lightweight concrete for load bearing
structural members. The plastic coarse aggregate (PCA) and plastic
fine aggregate (PFA) were produced from melted polyethylene
terephthalate (PET) bottles. Tests were conducted using three
different water–cement (w/c) ratios, such as 0.42, 0.48, and 0.57,
where PCA and PFA were used as 50% replacement of coarse and
fine aggregate respectively. Fresh and hardened properties of
concrete have been compared for natural aggregate concrete (NAC),
PCA concrete (PCC) and PFA concrete (PFC). The compressive
strength of concrete at 28 days varied with the water–cement ratio for
both the PCC and PFC. Between PCC and PFC, PFA concrete
showed the highest compressive strength (23.7 MPa) at 0.42 w/c ratio
and also the lowest compressive strength (13.7 MPa) at 0.57 w/c
ratio. Significant reduction in concrete density was mostly observed
for PCC samples, ranging between 1977–1924 kg/m³. With the
increase in water–cement ratio PCC achieved higher workability
compare to both NAC and PFC. It was found that both the PCA and
PFA contained concrete achieved the required compressive strength
to be used for structural purpose as partial replacement of the natural
aggregate; but to obtain the desired lower density as lightweight
concrete the PCA is most suited.
Abstract: The quality and condition of perishable products
delivered to the market and their subsequent selling prices are
directly affected by the care taken during harvesting and handling.
Mechanical injury, in fact, occurs at all stages, from pre-harvest
operations through post-harvest handling, packing and transport to
the market. The main implications of this damage are the reduction of
the product’s quality and economical losses related to the shelf life
diminution. For most perishable products, the shelf life is relatively
short and it is typically dictated by microbial growth related to the
application of dynamic and static loads during transportation. This
paper presents the correlation between vibration levels and
microbiological growth on strawberries and woodland strawberries
and detects the presence of volatile organic compounds (VOC) in
order to develop an intelligent logistic unit capable of monitoring
VOCs using a specific sensor system. Fresh fruits were exposed to
vibrations by means of a vibrating table in a temperature-controlled
environment. Microbiological analyses were conducted on samples,
taken at different positions along the column of the crates. The values
obtained were compared with control samples not exposed to
vibrations and the results show that different positions along the
column influence the development of bacteria, yeasts and filamentous
fungi.
Abstract: All the software engineering researches and best
industry practices aim at providing software products with high
degree of quality and functionality at low cost and less time. These
requirements are addressed by the Component Based Software
Engineering (CBSE) as well. CBSE, which deals with the software
construction by components’ assembly, is a revolutionary extension
of Software Engineering. CBSE must define and describe processes
to assure timely completion of high quality software systems that are
composed of a variety of pre built software components. Though
these features provide distinct and visible benefits in software design
and programming, they also raise some challenging problems. The
aim of this work is to summarize the pertinent issues and
considerations in CBSE to make an understanding in forms of
concepts and observations that may lead to development of newer
ways of dealing with the problems and challenges in CBSE.
Abstract: Microalgae Meyerella planktonica is a potential
biofuel source because it can grow in bulk in either autotrophic or
heterotrophic condition. However, the quantitative growth of this
algal type is still low as it tends to precipitates on the bottom.
Besides, the lipid concentration is still low when grown in
autotrophic condition. In contrast, heterotrophic condition can
enhance the lipid concentration. The combination of autotrophic
condition and agitation treatment was conducted to increase the
density of the culture. On the other hand, a heterotrophic condition
was set up to raise the lipid production. A two-stage experiment
was applied to increase the density at the first step and to increase
the lipid concentration in the next step. The autotrophic condition
resulted higher density but lower lipid concentration compared to
heterotrophic one. The agitation treatment produced higher density
in both autotrophic and heterotrophic conditions. The two-stage
experiment managed to enhance the density during the autotrophic
stage and the lipid concentration during the heterotrophic stage.
The highest yield was performed by using 0.4% v/v glycerol as a
carbon source (2.9±0.016 x 10^6 cells w/w) attained 7 days after the
heterotrophic stage began. The lipid concentration was stable
starting from day 7.
Abstract: In our research we aimed to test a managerial
approach for the fuzzy front end (FFE) of innovation by creating
controlled experiment/ business case in a breakthrough innovation
development. The experiment was in the sport industry and covered
all aspects of the customer discovery stage from ideation to
prototyping followed by patent application. In the paper we describe
and analyze mile stones, tasks, management challenges, decisions
made to create the break through innovation, evaluate overall
managerial efficiency that was at the considered FFE stage.
We set managerial outcome of the FFE stage as a valid product
concept in hand. In our paper we introduce hypothetical construct
“Q-factor” that helps us in the experiment to distinguish quality of
FFE outcomes.
The experiment simulated for entrepreneur the FFE of innovation
and put on his shoulders responsibility for the outcome of valid
product concept. While developing managerial approach to reach the
outcome there was a decision to look on product concept from the
cognitive psychology and cognitive science point of view. This view
helped us to develop the profile of a person whose projection (mental
representation) of a new product could optimize for a manager or
entrepreneur FFE activities. In the experiment this profile was tested
to develop breakthrough innovation for swimmers. Following the
managerial approach the product concept was created to help
swimmers to feel/sense water. The working prototype was developed
to estimate the product concept validity and value added effect for
customers.
Based on feedback from coachers and swimmers there were strong
positive effect that gave high value for customers, and for the
experiment – the valid product concept being developed by proposed
managerial approach for the FFE.
In conclusions there is a suggestion of managerial approach that
was derived from experiment.
Abstract: The main objective of this paper is to provide a new
methodology for road safety assessment in Oman through the
development of suitable accident prediction models. GLM technique
with Poisson or NBR using SAS package was carried out to develop
these models. The paper utilized the accidents data of 31 un-signalized
T-intersections during three years. Five goodness-of-fit
measures were used to assess the overall quality of the developed
models. Two types of models were developed separately; the flow-based
models including only traffic exposure functions, and the full
models containing both exposure functions and other significant
geometry and traffic variables.
The results show that, traffic exposure functions produced much
better fit to the accident data. The most effective geometric variables
were major-road mean speed, minor-road 85th percentile speed,
major-road lane width, distance to the nearest junction, and right-turn
curb radius.
The developed models can be used for intersection treatment or
upgrading and specify the appropriate design parameters of T-intersections.
Finally, the models presented in this thesis reflect the intersection
conditions in Oman and could represent the typical conditions in
several countries in the middle east area, especially gulf countries.