Abstract: Recently, Graphene Nanoribbon Field Effect Transistors (GNR FETs) attract a great deal of attention due to their better performance in comparison with conventional devices. In this paper, channel length Modulation (CLM) effect on the electrical characteristics of GNR FETs is analytically studied and modeled. To this end, the special distribution of the electric potential along the channel and current-voltage characteristic of the device is modeled. The obtained results of analytical model are compared to the experimental data of published works. As a result, it is observable that considering the effect of CLM, the current-voltage response of GNR FET is more realistic.
Abstract: This paper deals with different modeling aspects of masonry infill: no infill model, Layered shell infill model, and strut infill model. These models consider the complicated behavior of the in-filled plane frames under lateral load similar to an earthquake load. Three strut infill models are used: NBCC (2005) strut infill model, ASCE/SEI 41-06 strut infill model and proposed strut infill model based on modification to Canadian, NBCC (2005) strut infill model. Pushover and modal analyses of a masonry infill concrete frame with a single storey and an existing 5-storey RC building have been carried out by using different models for masonry infill. The corresponding hinge status, the value of base shear at target displacement as well as their dynamic characteristics have been determined and compared. A validation of the structural numerical models for the existing 5-storey RC building has been achieved by comparing the experimentally measured and the analytically estimated natural frequencies and their mode shapes. This study shows that ASCE/SEI 41-06 equation underestimates the values for the equivalent properties of the diagonal strut while Canadian, NBCC (2005) equation gives realistic values for the equivalent properties. The results indicate that both ASCE/SEI 41-06 and Canadian, NBCC (2005) equations for strut infill model give over estimated values for dynamic characteristic of the building. Proposed modification to Canadian, NBCC (2005) equation shows that the fundamental dynamic characteristic values of the building are nearly similar to the corresponding values using layered shell elements as well as measured field results.
Abstract: Acute respiratory distress syndrome (ARDS) is characterized by permeability pulmonary edema and refractory hypoxemia. Lung-protective ventilation is still the key of better outcome in ARDS. Prone position reduces the trans-pulmonary pressure gradient, recruiting collapsed regions of the lung without increasing airway pressure or hyperinflation. Prone ventilation showed improved oxygenation and improved outcomes in severe hypoxemic patients with ARDS. This study evaluates the effect of prone positioning on mechanically ventilated patients with ARDS. A quasi-experimental design was carried out at Critical Care Units, on 60 patients. Two tools were utilized to collect data; Socio demographic, medical and clinical outcomes data sheet. Results of the present study indicated that prone position improves oxygenation in patients with severe respiratory distress syndrome. The study recommended that use prone position in patients with severe ARDS, as early as possible and for long sessions. Also, replication of this study on larger probability sample at the different geographical location is highly recommended.
Abstract: In this paper, a single phase soft switched Zero Voltage Transition and Zero Current Transition (ZVT-ZCT) Power Factor Correction (PFC) boost converter is proposed. In the proposed PFC converter, the main switch turns on with ZVT and turns off with ZCT without any additional voltage or current stresses. Auxiliary switch turns on and off with zero current switching (ZCS). Also, the main diode turns on with zero voltage switching (ZVS) and turns off with ZCS. The proposed converter has features like low cost, simple control and structure. The output current and voltage are controlled by the proposed PFC converter in wide line and load range. The theoretical analysis of converter is clarified and the operating steps are given in detail. The simulation results of converter are obtained for 500 W and 100 kHz. It is observed that the semiconductor devices operate with soft switching (SS) perfectly. So, the switching power losses are minimum. Also, the proposed converter has 0.99 power factor with sinusoidal current shape.
Abstract: In this paper, an improved active snubber cell is proposed on account of soft switching (SS) family of pulse width modulation (PWM) DC-DC converters. The improved snubber cell provides zero-voltage transition (ZVT) turn on and zero-current transition (ZCT) turn off for main switch. The snubber cell decreases EMI noise and operates with SS in a wide range of line and load voltages. Besides, all of the semiconductor devices in the converter operate with SS. There is no additional voltage and current stress on the main devices. Additionally, extra voltage stress does not occur on the auxiliary switch and its current stress is acceptable value. The improved converter has a low cost and simple structure. The theoretical analysis of converter is clarified and the operating states are given in detail. The experimental results of converter are obtained by prototype of 500 W and 100 kHz. It is observed that the experimental results and theoretical analysis of converter are suitable with each other perfectly.
Abstract: Historic paths in today's cities are facing the pressure
of the urban development due to the rapid urban growth. Every new
development is tearing the old urban fabric and the socio-economic
character of the historic paths. Furthermore, in some cases historic
paths suffer from negligence and decay. Kom El Dekka historic path
was one of those deteriorated paths in the city of Alexandria, Egypt,
in spite of its high heritage and socio-economic value. Therefore,
there was a need to develop urban regeneration strategies as a part of
a wider sustainable development vision, to handle the situation and
revitalize the path as a livable space in the heart of the city. This
study aims to develop a comprehensive assessment methodology to
evaluate the different values of the path and to create community-oriented
and economic-based analysis methodology for its socio-economic
values. These analysis and assessments provide strategies
for any regeneration action plan for Kom El Dekka historic path.
Abstract: This paper investigates the application of metallic
coatings on high fiber volume fraction carbon/epoxy polymer matrix
composites. For the grip of the metallic layer, a method of modifying
the surface of the composite by introducing a mixture of copper and
steel powder (filler powders) which can reduce the impact of thermal
spray particles. The powder was introduced to the surface at the time
of the forming. Arc spray was used to project the zinc coating layer.
The substrate was grit blasted to avoid poor adherence. The porosity, microstructure, and morphology of layers are
characterized by optical microscopy, SEM and image analysis. The
samples were studied also in terms of hardness and erosion resistance.
This investigation did not reveal any visible evidence damage to the
substrates. The hardness of zinc layer was about 25.94 MPa and the
porosity was around (∼6.70%). The erosion test showed that the zinc
coating improves the resistance to erosion. Based on the results
obtained, we can conclude that thermal spraying allows the production
of protective coating on PMC. Zinc coating has been identified as a
compatible material with the substrate. The filler powders layer
protects the substrate from the impact of hot particles and allows
avoiding the rupture of brittle carbon fibers.
Abstract: This paper presents the design and analysis of Liquid Crystal (LC) based tunable reflectarray antenna with slot embedded patch element configurations within X-band frequency range. The slots are shown to modify the surface current distribution on the patch element of reflectarray which causes the resonant patch element to provide different resonant frequencies depending on the slot dimensions. The simulated results are supported and verified by waveguide scattering parameter measurements of different reflectarray unit cells. Different rectangular slots on patch element have been fabricated and a change in resonant frequency from 10.46GHz to 8.78GHz has been demonstrated as the width of the rectangular slot is varied from 0.2W to 0.6W. The rectangular slot in the center of the patch element has also been utilized for the frequency tunable reflectarray antenna design based on K-15 Nematic LC. For the active reflectarray antenna design, a frequency tunability of 1.2% from 10GHz to 9.88GHz has been demonstrated with a dynamic phase range of 103° provided by the measured scattering parameter results. Time consumed by liquid crystals for reconfiguration, which is one of the drawback of LC based design, has also been disused in this paper.
Abstract: Seeking and sharing knowledge on online forums
have made them popular in recent years. Although online forums are
valuable sources of information, due to variety of sources of
messages, retrieving reliable threads with high quality content is an
issue. Majority of the existing information retrieval systems ignore
the quality of retrieved documents, particularly, in the field of thread
retrieval. In this research, we present an approach that employs
various quality features in order to investigate the quality of retrieved
threads. Different aspects of content quality, including completeness,
comprehensiveness, and politeness, are assessed using these features,
which lead to finding not only textual, but also conceptual relevant
threads for a user query within a forum. To analyse the influence of
the features, we used an adopted version of voting model thread
search as a retrieval system. We equipped it with each feature solely
and also various combinations of features in turn during multiple
runs. The results show that incorporating the quality features
enhances the effectiveness of the utilised retrieval system
significantly.
Abstract: In this research, students’ scientific attitude, computer anxiety, educational use of the Internet, academic achievement, and problematic use of the Internet are analyzed based on different variables (gender, parents’ educational level and daily access to the Internet). The research group involves 361 students from two middle schools which are located in the center of Konya. The “general survey method” is adopted in the research. In accordance with the purpose of the study, percentage, mean, standard deviation, independent samples t--‐test, ANOVA (variance) are employed in the study. A total of four scales are implemented. These four scales include a total of 13 sub-dimensions. The scores from these scales and their subscales are studied in terms of various variables. In the research, students’ scientific attitude, computer anxiety, educational use of the Internet, the problematic Internet use and academic achievement (gender, parent educational level, and daily access to the Internet) are investigated based on various variables and some significant relations are found.
Abstract: A 15-storey RC building, studied in this paper, is
representative of modern building type constructed in Madina City in
Saudi Arabia before 10 years ago. These buildings are almost
consisting of reinforced concrete skeleton i.e. columns, beams and
flat slab as well as shear walls in the stairs and elevator areas
arranged in the way to have a resistance system for lateral loads
(wind – earthquake loads). In this study, the dynamic properties of
the 15-storey RC building were identified using ambient motions
recorded at several, spatially-distributed locations within each
building. Three dimensional pushover analysis (Nonlinear static
analysis) was carried out using SAP2000 software incorporating
inelastic material properties for concrete, infill and steel. The effect
of modeling the building with and without infill walls, on the
performance point as well as capacity and demand spectra due to EQ
design spectrum function in Madina area has been investigated. ATC-
40 capacity and demand spectra are utilized to get the modification
factor (R) for the studied building. The purpose of this analysis is to
evaluate the expected performance of structural systems by
estimating, strength and deformation demands in design, and
comparing these demands to available capacities at the performance
levels of interest. The results are summarized and discussed.
Abstract: With the increasing number of people reviewing
products online in recent years, opinion sharing websites has become
the most important source of customers’ opinions. Unfortunately,
spammers generate and post fake reviews in order to promote or
demote brands and mislead potential customers. These are notably
destructive not only for potential customers, but also for business
holders and manufacturers. However, research in this area is not
adequate, and many critical problems related to spam detection have
not been solved to date. To provide green researchers in the domain
with a great aid, in this paper, we have attempted to create a highquality
framework to make a clear vision on review spam-detection
methods. In addition, this report contains a comprehensive collection
of detection metrics used in proposed spam-detection approaches.
These metrics are extremely applicable for developing novel
detection methods.
Abstract: The occurrences of precipitation, also commonly
referred as rain, in the form of "convective" and "stratiform" have
been identified to exist worldwide. In this study, the radar return
echoes or known as reflectivity values acquired from radar scans
have been exploited in the process of classifying the type of rain
endured. The investigation use radar data from Malaysian
Meteorology Department (MMD). It is possible to discriminate the
types of rain experienced in tropical region by observing the vertical
characteristics of the rain structure. .Heavy rain in tropical region
profoundly affects radiowave signals, causing transmission
interference and signal fading. Required wireless system fade margin
depends on the type of rain. Information relating to the two
mentioned types of rain is critical for the system engineers and
researchers in their endeavour to improve the reliability of
communication links. This paper highlights the quantification of
percentage occurrences over one year period in 2009.
Abstract: Rapid developments in technology in the present age
have made it necessary for communities to follow technological
developments and adapt themselves to these developments. One of
the fields that are most rapidly affected by these developments is
undoubtedly education. Determination of the attitudes of preservice
teachers, who live in an age of technology and get ready to raise
future individuals, is of paramount importance both educationally and
professionally. The purpose of this study was to analyze attitudes of
preservice teachers towards technology and some variables that
predict these attitudes (gender, daily duration of internet use, and the
number of technical devices owned). 329 preservice teachers
attending the education faculty of a large university in central Turkey
participated, on a volunteer basis, in this study, where relational
survey model was used as the research method. Research findings
reveal that preservice teachers’ attitudes towards technology are
positive and at the same time, the attitudes of male preservice
teachers towards technology are more positive than their female
counterparts. As a result of the stepwise multiple regression analysis
where factors predicting preservice teachers’ attitudes towards
technology, it was found that duration of daily internet use was the
strongest predictor of attitudes towards technology.
Abstract: Radio Frequency Identification (RFID) has become a
key technology in the emerging concept of Internet of Things (IoT).
Naturally, business applications would require the deployment of
various RFID systems developed by different vendors that use
different data formats and structures. This heterogeneity poses a
challenge in developing real-life IoT systems with RFID, as
integration is becoming very complex and challenging. Semantic
integration is a key approach to deal with this challenge. To do so,
ontology for RFID systems need to be developed in order to
annotated semantically RFID systems, and hence, facilitate their
integration. Accordingly, in this paper, we propose ontology for
RFID systems. The proposed ontology can be used to semantically
enrich RFID systems, and hence, improve their usage and reasoning.
Abstract: Public participation in recycling domestic waste is still
very low in Malaysia. Only 10.5% of solid waste was recycled up to
now which is far below than of in developed countries. Therefore,
understanding public motivations towards recycling domestic waste
are important to improve current recycling rate. Thus, this study
attempts to identify what are the possible motivations and hindrances
for the public to recycle. Open-ended questions format were
administered to 484 people in Kota Kinabalu, Sabah, Malaysia. Two
specific questions we asked to explore their general determinants and
barriers in practicing recycling: “What motivates you to recycle?”
and “What are the barriers you encountered in doing recycling
activities?” Thematic was conducted on the open-ended questions in
which themes were created with the raw comments. It was found that
the underlying recycling motivations are (i) awareness’ towards the
environment; (ii) benefits to the society and individual; and (iii)
social influence. Non participations are influence by (i) attitudes; (ii)
commitment; (iii) facilities; (iv) knowledge; (v) inconvenience; and
(vi) enforcement.
Abstract: This paper illustrates the background of various
concepts, approaches, terminologies used to describe the basic
framework of an Islamic Hotel Room design. This paper reviews the
theoretical views in establishing a suitable and optimum environment
for Muslim as well as non-Muslim guests in hotel rooms while
according to shariah. It involves a few research methodologies that
requires the researcher to study on a few characteristics needed to
create more efficient rooms in terms of social interaction, economic
growth and other tolerable elements. This paper intends on revealing
the elements that are vital and may contribute for hotels in achieving
a more conclusive research on space planning for hotel rooms
focusing on the shariah and Muslim guests. Malaysia is an Islamic
country and has billion of tourists coming over for business and
recreational purposes. Therefore, having a righteous environment that
best suit this target user is important in terms of generating the
economy as well as providing a better understanding to the
community on the benefits of applying these qualities in a
conventional resort design.
Abstract: This paper introduces a boost converter with a new
active snubber cell. In this circuit, all of the semiconductor
components in the converter softly turns on and turns off with the
help of the active snubber cell. Compared to the other converters, the
proposed converter has advantages of size, number of components
and cost. The main feature of proposed converter is that the extra
voltage stresses do not occur on the main switches and main diodes.
Also, the current stress on the main switch is acceptable level.
Moreover, the proposed converter can operates under light load
conditions and wide input line voltage. In this study, the operating
principle of the proposed converter is presented and its operation is
verified with the Proteus simulation software for a 1 kW and 100 kHz
model.
Abstract: The MEMS pressure sensor has been introduced and
presented in this paper. The types of pressure sensor and its theory of
operation are also included. The latest MEMS technology, the
fabrication processes of pressure sensor are explored and discussed.
Besides, various device applications of pressure sensor such as tire
pressure-monitoring system, diesel particulate filter and others are
explained. Due to further miniaturization of the device nowadays, the
pressure sensor with nanotechnology (NEMS) is also reviewed. The
NEMS pressure sensor is expected to have better performance as well
as lower in its cost. It has gained an excellent popularity in many
applications.
Abstract: Nanotechnology has become the world attention in
various applications including the solar cells devices due to the
uniqueness and benefits of achieving low cost and better
performances of devices. Recently, thin film solar cells such as
Cadmium Telluride (CdTe), Copper-Indium-Gallium-diSelenide
(CIGS), Copper-Zinc-Tin-Sulphide (CZTS), and Dye-Sensitized
Solar Cells (DSSC) enhanced by nanotechnology have attracted
much attention. Thus, a compilation of nanotechnology devices
giving the progress in the solar cells has been presented. It is much
related to nanoparticles or nanocrystallines, carbon nanotubes, and
nanowires or nanorods structures.