Abstract: Nanofibers are effective materials which have
frequently been investigated to produce high quality air filters. As an
environmental approach our aim is to achieve nanofibers by melting.
In spun-bond systems extruder, spin-pump, nozzle package and
attenuator are used. Molten polymer which flows from extruder is
made steady by spin-pump. Regular melt passes through nozzle holes
and forms fibers under high pressure. The fibers pulled from nozzle
are shrunk to micron size by an attenuator; after solidification, they
are collected on a conveyor. In this research different designs of
attenuator system have been studied; and also CFD analysis has been
done on these different designs. Afterwards, one of these designs
tested and finally some optimizations have been done to reduce
pressure loss and increase air velocity.
Abstract: Groundwater inflow to the tunnels is one of the most
important problems in tunneling operation. The objective of this
study is the investigation of model dimension effects on tunnel inflow
assessment in discontinuous rock masses using numerical modeling.
In the numerical simulation, the model dimension has an important
role in prediction of water inflow rate. When the model dimension is
very small, due to low distance to the tunnel border, the model
boundary conditions affect the estimated amount of groundwater flow
into the tunnel and results show a very high inflow to tunnel. Hence,
in this study, the two-dimensional universal distinct element code
(UDEC) used and the impact of different model parameters, such as
tunnel radius, joint spacing, horizontal and vertical model domain
extent has been evaluated. Results show that the model domain extent
is a function of the most significant parameters, which are tunnel
radius and joint spacing.
Abstract: This paper presents system level CMOS solid-state
nanopore techniques enhancement for speedup next generation
molecular recording and high throughput channels. This discussion
also considers optimum number of base-pair (bp) measurements
through channel as an important role to enhance potential read
accuracy. Effective power consumption estimation offered suitable
range of multi-channel configuration. Nanopore bp extraction model
in statistical method could contribute higher read accuracy with
longer read-length (200 < read-length). Nanopore ionic current
switching with Time Multiplexing (TM) based multichannel readout
system contributed hardware savings.
Abstract: Using the first-principles full-potential linearized
augmented plane wave plus local orbital (FP-LAPW+lo) method
based on density functional theory (DFT), we have investigated the
electronic structure and magnetism of full Heusler alloys Co2ZrGe
and Co2NbB. These compounds are predicted to be half-metallic
ferromagnets (HMFs) with a total magnetic moment of 2.000 B per
formula unit, well consistent with the Slater-Pauling rule.
Calculations show that both the alloys have an indirect band gaps, in
the minority-spin channel of density of states (DOS), with values of
0.58 eV and 0.47 eV for Co2ZrGe and Co2NbB, respectively.
Analysis of the DOS and magnetic moments indicates that their
magnetism is mainly related to the d-d hybridization between the Co
and Zr (or Nb) atoms. The half-metallicity is found to be relatively
robust against volume changes. In addition, an atom inside molecule
AIM formalism and an electron localization function ELF were also
adopted to study the bonding properties of these compounds, building
a bridge between their electronic and bonding behavior.
As they have a good crystallographic compatibility with the lattice of
semiconductors used industrially and negative calculated cohesive
energies with considerable absolute values these two alloys could be
promising magnetic materials in the spintronic field.
Abstract: An innovative concept called “Flexy-Energy” is developing at 2iE. This concept aims to produce electricity at lower cost by smartly mix different available energy sources in accordance to the load profile of the region. With a higher solar irradiation and due to the fact that Diesel generator are massively used in sub-Saharan rural areas, PV/Diesel hybrid systems could be a good application of this concept and a good solution to electrify this region, provided they are reliable, cost effective and economically attractive to investors. Presentation of the developed approach is the aims of this paper. The PV/Diesel hybrid system designed consists to produce electricity and/or heat from a coupling between Diesel Diesel generators and PV panels without batteries storage, while ensuring the substitution of gasoil by bio-fuels available in the area where the system will be installed. The optimal design of this system is based on his technical performances; the Life Cycle Cost (LCC) and Levelized Cost of Energy are developed and use as economic criteria. The Net Present Value (NPV), the internal rate of return (IRR) and the discounted payback (DPB) are also evaluated according to dual electricity pricing (in sunny and unsunny hours). The PV/Diesel hybrid system obtained is compared to the standalone Diesel Diesel generators. The approach carried out in this paper has been applied to Siby village in Mali (Latitude 12 ° 23'N 8 ° 20'W) with 295 kWh as daily demand.This approach provides optimal physical characteristics (size of the components, number of component) and dynamical characteristics in real time (number of Diesel generator on, their load rate, fuel specific consumptions, and PV penetration rate) of the system. The system obtained is slightly cost effective; but could be improved with optimized tariffing strategies.
Abstract: The aim of this paper is to understand emerging
learning conditions, when a visual analytics is implemented and used
in K 12 (education). To date, little attention has been paid to the role
visual analytics (digital media and technology that highlight visual
data communication in order to support analytical tasks) can play in
education, and to the extent to which these tools can process
actionable data for young students. This study was conducted in three
public K 12 schools, in four social science classes with students aged
10 to 13 years, over a period of two to four weeks at each school.
Empirical data were generated using video observations and analyzed
with help of metaphors within Actor-network theory (ANT). The
learning conditions are found to be distinguished by broad
complexity, characterized by four dimensions. These emerge from
the actors’ deeply intertwined relations in the activities. The paper
argues in relation to the found dimensions that novel approaches to
teaching and learning could benefit students’ knowledge building as
they work with visual analytics, analyzing visualized data.
Abstract: Corrosion of concrete sewer pipes induced by sulfuric
acid is an acknowledged problem and a ticking time-bomb to sewer
operators. Whilst the chemical reaction of the corrosion process is
well-understood, the indirect roles of other parameters in the
corrosion process which are found in sewer environment are not
highly reflected on. This paper reports on a field studies undertaken
in Austria and United Kingdom, where the parameters of
temperature, pH, H2S and CO2 were monitored over a period of time.
The study establishes that (i) effluent temperature and pH have
similar daily pattern and peak times, when examined in minutes
scale; (ii) H2S and CO2 have an identical hourly pattern; (iii) H2S
instant or shifted relation to effluent temperature is governed by the
root mean square value of CO2.
Abstract: Real bronchial tree is very complicated piping system.
Analysis of flow and pressure losses in this system is very difficult.
Due to the complex geometry and the very small size in the lower
generations is examination by CFD possible only in the central part
of bronchial tree. For specify the pressure losses of lower generations
is necessary to provide a mathematical equation. Determination of
mathematical formulas for calculation of pressure losses in the real
lungs is time consuming and inefficient process due to its complexity
and diversity. For these calculations is necessary to slightly simplify
the geometry of lungs (same cross-section over the length of
individual generation) or use one of the idealized models of lungs
(Horsfield, Weibel). The article compares the values of pressure
losses obtained from CFD simulation of air flow in the central part of
the real bronchial tree with the values calculated in a slightly
simplified real lungs by using a mathematical relationship derived
from the Bernoulli and continuity equations. The aim of the article is
to analyse the accuracy of the analytical method and its possibility of
use for the calculation of pressure losses in lower generations, which
is difficult to solve by numerical method due to the small geometry.
Abstract: This paper reports the worldwide status of building
information modeling (BIM) adoption from the perspectives of the
engagement level, the Hype Cycle model, the technology diffusion
model, and BIM services. An online survey was distributed, and 156
experts from six continents responded. Overall, North America was
the most advanced continent, followed by Oceania and Europe.
Countries in Asia perceived their phase mainly as slope of
enlightenment (mature) in the Hype Cycle model. In the technology
diffusion model, the main BIM-users worldwide were “early majority”
(third phase), but those in the Middle East/Africa and South America
were “early adopters” (second phase). In addition, the more advanced
the country, the more number of BIM services employed in general. In
summary, North America, Europe, Oceania, and Asia were advancing
rapidly toward the mature stage of BIM, whereas the Middle
East/Africa and South America were still in the early phase. The
simple indexes used in this study may be used to track the worldwide
status of BIM adoption in long-term surveys.
Abstract: Recently, the competition between websites becomes
intense. How to make users “adopt” their websites is an issue of urgent
importance for online communities companies. Social procedures
(such as social influence) can possibly explain how and why users’
technologies usage behaviors affect other people to use the
technologies. This study proposes two types of social influences on the
initial usage of Facebook Check In-friends and group members.
Besides, this study combines social influences theory and social
network theory to explore the factors influencing initial usage of
Facebook Check In. This study indicates that Facebook friends’
previous usage of Facebook Check In and Facebook group members’
previous usage of Facebook Check In will positively influence focal
actors’ Facebook Check In adoption intention, and network centrality
will moderate the relationships among Facebook friends’ previous
usage of Facebook Check In, Facebook group members’ previous
usage of Facebook Check In and focal actors’ Facebook Check In
adoption intention. The article concludes with contributions to
academic research and practice.
Abstract: In urban context, urban nodes such as amenity or
hazard will certainly affect house price, while classic hedonic analysis
will employ distance variables measured from each urban nodes.
However, effects from distances to facilities on house prices generally
do not represent the true price of the property. Distance variables
measured on the same surface are suffering a problem called
multicollinearity, which is usually presented as magnitude variance
and mean value in regression, errors caused by instability. In this paper,
we provided a theoretical framework to identify and gather the data
with less bias, and also provided specific sampling method on locating
the sample region to avoid the spatial multicollinerity problem in three
distance variable’s case.
Abstract: In recent years parasitic antenna play major role in
MIMO systems because of their gain and spectral efficiency. In this
paper, single RF chain MIMO transmitter is designed using
reconfigurable parasitic antenna. The Spatial Modulation (SM) is a
recently proposed scheme in MIMO scenario which activates only
one antenna at a time. The SM entirely avoids ICI and IAS, and only
requires a single RF chain at the transmitter. This would switch ON a
single transmit-antenna for data transmission while all the other
antennas are kept silent. The purpose of the parasitic elements is to
change the radiation pattern of the radio waves which is emitted from
the driven element and directing them in one direction and hence
introduces transmit diversity. Diode is connect between the patch and
ground by changing its state (ON and OFF) the parasitic element act
as reflector and director and also capable of steering azimuth and
elevation angle. This can be achieved by changing the input
impedance of each parasitic element through single RF chain. The
switching of diode would select the single parasitic antenna for
spatial modulation. This antenna is expected to achieve maximum
gain with desired efficiency.
Abstract: Generating random numbers are mainly used to create
secret keys or random sequences. It can be carried out by various
techniques. In this paper we present a very simple and efficient
pseudo random number generator (PRNG) based on chaotic maps
and S-Box tables. This technique adopted two main operations one to
generate chaotic values using two logistic maps and the second to
transform them into binary words using random S-Box tables.
The simulation analysis indicates that our PRNG possessing
excellent statistical and cryptographic properties.
Abstract: This paper aims to investigate the influence of quality
of education and quality of research, provided by local educational
institutions, on the adoption of Information and Communication
Technology (ICT) in managing business operations for companies in
Saudi market. A model was developed and tested using data collected
from 138 Chief Executive Officers (CEOs) of foreign companies in
diverse business sectors. The data is analyzed and managed using
multivariate approaches through standard statistical packages. The
results showed that educational quality has little contribution to the
ICT adoption while research quality seems to play a more prominent
role. These results are analyzed in terms of business environment and
market constraints and further extended to the perceived effectiveness
of applied pedagogical approaches in schools and universities.
Abstract: The feedbacks obtained regarding the sense of
presence from pilot users operating a Mobile Robotic presence
(MRP) system to visit a simulated museum are reported in this paper.
The aim is to investigate how much the perception of system’s
usefulness and ease of use is affected by operators’ sense of social
telepresence (presence) in the remote location. Therefore, scenarios
of visiting a museum are simulated and the user operators are
supposed to perform some regular tasks inside the remote
environment including interaction with local users, navigation and
visiting the artworks. Participants were divided into two groups,
those who had previous experience of operation and interaction with
a MRP system and those who never had experience. Based on the
results, both groups provided different feedbacks. Moreover, there
was a significant association between user’s sense of presence and
their perception of system usefulness and ease of use.
Abstract: We have been grouping and developing various kinds
of practical, promising sensing applied systems concerning
agricultural advancement and technical tradition (guidance). These
include advanced devices to secure real-time data related to worker
motion, and we analyze by methods of various advanced statistics and
human dynamics (e.g. primary component analysis, Ward system
based cluster analysis, and mapping). What is more, we have been
considering worker daily health and safety issues. Targeted fields are
mainly common farms, meadows, and gardens. After then, we
observed and discussed time-line style, changing data. And, we made
some suggestions. The entire plan makes it possible to improve both
the aforementioned applied systems and farms.
Abstract: This paper shortly describes various types of biomass
and a growing number of facilities utilizing the biomass in the Czech
Republic. The considerable part of this paper deals with energy
parameters of the most frequently used types of biomass and results
of their gasification testing. Sixteen most used "Czech" woody plants
and grasses were selected; raw, element and biochemical analyses
were performed and basic calorimetric values, ash composition, and
ash characteristic temperatures were identified. Later, each biofuel
was tested in a fluidized bed gasifier. The essential part of this paper
provides results of the gasification of selected biomass types.
Operating conditions are described in detail with a focus on
individual fuels properties. Gas composition and impurities content
are also identified. In terms of operating conditions and gas quality,
the essential difference occurred mainly between woody plants and
grasses. The woody plants were evaluated as more suitable fuels for
fluidized bed gasifiers. Testing results significantly help with a
decision-making process regarding suitability of energy plants for
growing and with a selection of optimal biomass-treatment
technology.
Abstract: Modeling and forecasting dynamics of rainfall
occurrences constitute one of the major topics, which have been
largely treated by statisticians, hydrologists, climatologists and many
other groups of scientists. In the same issue, we propose, in the
present paper, a new hybrid method, which combines Extreme
Values and fractal theories. We illustrate the use of our methodology
for transformed Emberger Index series, constructed basing on data
recorded in Oujda (Morocco).
The index is treated at first by Peaks Over Threshold (POT)
approach, to identify excess observations over an optimal threshold u.
In the second step, we consider the resulting excess as a fractal object
included in one dimensional space of time. We identify fractal
dimension by the box counting. We discuss the prospect descriptions
of rainfall data sets under Generalized Pareto Distribution, assured by
Extreme Values Theory (EVT). We show that, despite of the
appropriateness of return periods given by POT approach, the
introduction of fractal dimension provides accurate interpretation
results, which can ameliorate apprehension of rainfall occurrences.
Abstract: The work allowed gaining knowledge about redox and
speciation changes of As, Cr and Sb ionic forms in Klodnica River
water. This kind of studies never has been conducted in this region of
Poland. In study optimized and validated previously HPLC-ICP-MS
methods for determination of As, Sb and Cr was used. Separation
step was done using high-performance liquid chromatograph
equipped with ion-exchange column followed by ICP-MS
spectrometer detector. Preliminary studies included determination of
the total concentration of As, Sb and Cr, pH, Eh, temperature and
conductivity of the water samples. The study was conducted monthly
from March to August 2014, at six points on the Klodnica River. The
results indicate that exceeded at acceptable concentration of total Cr
and Sb was observed in Klodnica River and we should qualify
Klodnica River waters below the second purity class. In Klodnica
River waters dominates oxidized antimony and arsenic forms, as well
as the two forms of chromium Cr(VI) and Cr(III). Studies have also
shown the methyl derivative of arsenic's presence.
Abstract: In a multi-cultural learning context, where ties are
weak and dynamic, combining qualitative with quantitative research
methods may be more effective. Such a combination may also allow
us to answer different types of question, such as about people’s
perception of the network. In this study the use of observation,
interviews and photos were explored as ways of enhancing data from
social network questionnaires. Integrating all of these methods was
found to enhance the quality of data collected and its accuracy, also
providing a richer story of the network dynamics and the factors that
shaped these changes over time.