Abstract: Electrical resistivity is a fundamental parameter of metals or electrical conductors. Since resistivity is a function of temperature, in order to completely understand the behavior of metals, a temperature dependent theoretical model is needed. A model based on physics principles has recently been developed to obtain an equation that relates electrical resistivity to temperature. This equation is dependent upon a parameter associated with the electron travel time before being scattered, and a parameter that relates the energy of the atoms and their separation distance. Analysis of the energy parameter reveals that the equation is optimized if the proportionality term in the equation is not constant but varies over the temperature range. Additional analysis reveals that the theoretical equation can be used to determine the mean free path of conduction electrons, the number of defects in the atomic lattice, and the ‘equivalent’ charge associated with the metallic bonding of the atoms. All of this analysis provides validation for the theoretical model and provides insight into the behavior of metals where performance is affected by temperatures (e.g., integrated circuits and temperature sensors).
Abstract: To simulate heating systems in buildings, a research oriented computer code has been developed in Sharif University of Technology in Iran where the climate, existing heating equipment in buildings, consumer behavior and their interactions are considered for simulating energy consumption in conventional systems such as heaters, radiators and fan-coils. In order to validate the computer code, the available data of five buildings was used and the computed consumed energy was compared with the estimated energy extracted from monthly bills. The initial heating system was replaced by the alternative system and the effect of this change was observed on the energy consumption. As a result, the effect of changing heating equipment on energy consumption was investigated in different climates. Changing heater to radiator renders energy conservation up to 50% in all climates and changing radiator to fan-coil decreases energy consumption in climates with cold and dry winter.
Abstract: The peng-Robinson (PR), a cubic equation of state (EoS), is extended to polymers by using a single set of energy (A1, A2, A3) and co-volume (b) parameters per polymer fitted to experimental volume data. Excellent results for the volumetric behavior of the 11 polymer up to 2000 bar pressure are obtained. The EoS is applied to the correlation and prediction of Henry constants in polymer solutions comprising three polymer and many nonpolar and polar solvents, including supercritical gases. The correlation achieved with two adjustable parameter is satisfactory compared with the experimental data. As a result, the present work provides a simple and useful model for the prediction of Henry's constant for polymer containing systems including those containing polar, nonpolar and supercritical fluids.
Abstract: Context awareness is a capability whereby mobile
computing devices can sense their physical environment and adapt
their behavior accordingly. The term context-awareness, in
ubiquitous computing, was introduced by Schilit in 1994 and has
become one of the most exciting concepts in early 21st-century
computing, fueled by recent developments in pervasive computing
(i.e. mobile and ubiquitous computing). These include computing
devices worn by users, embedded devices, smart appliances, sensors
surrounding users and a variety of wireless networking technologies.
Context-aware applications use context information to adapt
interfaces, tailor the set of application-relevant data, increase the
precision of information retrieval, discover services, make the user
interaction implicit, or build smart environments. For example: A
context aware mobile phone will know that the user is currently in a
meeting room, and reject any unimportant calls. One of the major
challenges in providing users with context-aware services lies in
continuously monitoring their contexts based on numerous sensors
connected to the context aware system through wireless
communication. A number of context aware frameworks based on
sensors have been proposed, but many of them have neglected the
fact that monitoring with sensors imposes heavy workloads on
ubiquitous devices with limited computing power and battery. In this
paper, we present CALEEF, a lightweight and energy efficient
context aware framework for resource limited ubiquitous devices.
Abstract: The current study describes a multi-objective optimization technique for positioning of houses in a residential neighborhood. The main task is the placement of residential houses in a favorable configuration satisfying a number of objectives. Solving the house layout problem is a challenging task. It requires an iterative approach to satisfy design requirements (e.g. energy efficiency, skyview, daylight, roads network, visual privacy, and clear access to favorite views). These design requirements vary from one project to another based on location and client preferences. In the Gulf region, the most important socio-cultural factor is the visual privacy in indoor space. Hence, most of the residential houses in this region are surrounded by high fences to provide privacy, which has a direct impact on other requirements (e.g. daylight and direction to favorite views). This investigation introduces a novel technique to optimally locate and orient residential buildings to satisfy a set of design requirements. The developed technique explores the search space for possible solutions. This study considers two dimensional house planning problems. However, it can be extended to solve three dimensional cases.
Abstract: Finger spelling is an art of communicating by signs
made with fingers, and has been introduced into sign language to serve
as a bridge between the sign language and the verbal language.
Previous approaches to finger spelling recognition are classified into
two categories: glove-based and vision-based approaches. The
glove-based approach is simpler and more accurate recognizing work
of hand posture than vision-based, yet the interfaces require the user to
wear a cumbersome and carry a load of cables that connected the
device to a computer. In contrast, the vision-based approaches provide
an attractive alternative to the cumbersome interface, and promise
more natural and unobtrusive human-computer interaction. The
vision-based approaches generally consist of two steps: hand
extraction and recognition, and two steps are processed independently.
This paper proposes real-time vision-based Korean finger spelling
recognition system by integrating hand extraction into recognition.
First, we tentatively detect a hand region using CAMShift algorithm.
Then fill factor and aspect ratio estimated by width and height
estimated by CAMShift are used to choose candidate from database,
which can reduce the number of matching in recognition step. To
recognize the finger spelling, we use DTW(dynamic time warping)
based on modified chain codes, to be robust to scale and orientation
variations. In this procedure, since accurate hand regions, without
holes and noises, should be extracted to improve the precision, we use
graph cuts algorithm that globally minimize the energy function
elegantly expressed by Markov random fields (MRFs). In the
experiments, the computational times are less than 130ms, and the
times are not related to the number of templates of finger spellings in
database, as candidate templates are selected in extraction step.
Abstract: The purpose of this study is to revisit the concept of
rape as represented by professionals in the literature as well as its
perception (beliefs and attitudes) in the population at large and to
propose methodological improvements to its measurement tool. Rape
is a serious crime threatening its victim-s physical and mental health
and integrity; and as such is legally prosecuted in all modern
societies. The problem is not in accepting or rejecting rape as a
criminal act, but rather in the vagueness of its interpretations and
“justifications" maintained in the mentality of modern societies -
known in the literature as the phenomenon of "rape-myth". The rapemyth
can be studied from different perspectives: criminology,
sociology, ethics, medicine and psychology. Its investigation requires
rigorous scientific objectivity, free of passion (victims of rape are at
risk of emotional bias), free of activism (social activists, even if wellintentioned
are also biased), free of any pre-emptive assumptions or
prejudices. To apply a rigorous scientific procedure, we need a solid,
valid and reliable measurement. Rape is a form of heterosexual or
homosexual aggression, violently forcing the victim to give-in in the
sexual activity of the aggressor against her/his will. Human beings
always try to “understand" or find a reason justifying their acts.
Psychological literature provides multiple clinical and experimental
examples of it; just to mention the famous studies by Milgram on the
level of electroshock delivered by the “teacher" towards the “learner"
if “scientifically justifiable" or the studies on the behavior of
“prisoners" and the “guards" and many other experiments and field
observations. Sigmund Freud presented the phenomenon of
unconscious justification and called it rationalization. The multiple
justifications, rationalizations and repeated opinions about sexual
behavior contribute to a myth maintained in the society. What kind of
“rationale" our societies apply to “understand" the non-consensual
sexual behavior? There are many, just to mention few:
• Sex is a ludistic activity for both participants, therefore –
even if not consented – it should bring pleasure to both.
• Everybody wants sex, but only men are allowed to manifest
it openly while women have to pretend the opposite, thus men have
to initiate sexual behavior and women would follow.
• A person who strongly needs sex is free to manifest it and
struggle to get it; the person who doesn-t want it must not reveal
her/his sexual attraction and avoid risky situations; otherwise she/he
is perceived as a promiscuous seducer.
• A person who doesn-t fight against the sexual initiator
unconsciously accepts the rape (does it explain why homosexual
rapes are reported less frequently than rapes against women?).
• Women who are raped deserve it because their wardrobe is
very revealing and seducing and they ''willingly'' go to highly risky
places (alleys, dark roads, etc.).
• Men need to ventilate their sexual energy and if they are
deprived of a partner their urge to have sex is difficult to control.
• Men are supposed to initiate and insist even by force to have
sex (their testosterone makes them both sexual and aggressive).
The paper overviews numerous cultural beliefs about masculine
versus feminine behavior and their impact on the “rape myth".
Abstract: Preprocessing of speech signals is considered a crucial step in the development of a robust and efficient speech or speaker recognition system. In this paper, we present some popular statistical outlier-detection based strategies to segregate the silence/unvoiced part of the speech signal from the voiced portion. The proposed methods are based on the utilization of the 3 σ edit rule, and the Hampel Identifier which are compared with the conventional techniques: (i) short-time energy (STE) based methods, and (ii) distribution based methods. The results obtained after applying the proposed strategies on some test voice signals are encouraging.
Abstract: The continued growth of the cities is causing an
increase of the amount of surface to illuminate. However, this rise
into lighting brings some unintended consequences such as increased
of energy consumption or the light pollution. To make these effects
less intrusive as possible some councils have chosen to perform a
part-night lighting in some areas. Nonetheless, this kind of shutdown
may cause serious problems which we intend to highlight in this
paper.
Abstract: Optical emission based on excitonic scattering processes becomes important in dense exciton systems in which the average distance between excitons is of the order of a few Bohr radii but still below the exciton screening threshold. The phenomena due to interactions among excited states play significant role in the emission near band edge of the material. The theory of two-exciton collisions for GaAs/AlGaAs quantum well systems is a mild attempt to understand the physics associated with the optical spectra due to excitonic scattering processes in these novel systems. The four typical processes considered give different spectral shape, peak position and temperature dependence of the emission spectra. We have used the theory of scattering together with the second order perturbation theory to derive the radiative power spontaneously emitted at an energy ħω by these processes. The results arrived at are purely qualitative in nature. The intensity of emitted light in quantum well systems varies inversely to the square of temperature, whereas in case of bulk materials it simply decreases with the temperature.
Abstract: Transmission and distribution lines are vital links between the generating unit and consumers. They are exposed to atmosphere, hence chances of occurrence of fault in transmission line is very high which has to be immediately taken care of in order to minimize damage caused by it. In this paper Discrete wavelet transform of voltage signals at the two ends of transmission lines have been analyzed. The transient energy of the detail information of level five is calculated for different fault conditions. It is observed that the variation of transient energy of healthy and faulted line can give important information which can be very useful in classifying and locating the fault.
Abstract: Discharges in hydrogen, ignited by wire explosion, with current amplitude up to 1.5 MA were investigated. Channel diameter oscillations were observed on the photostreaks. Voltage and current curves correlated with the photostreaks. At initial gas pressure of 5-35 MPa the oscillation period was proportional to square root of atomic number of the initiating wire material. These oscillations were associated with aligned magnetic and gas-kinetic pressures. At initial pressure of 80-160 MPa acoustic pressure fluctuations on the discharge chamber wall were increased up to 150 MPa and there were the growth of voltage fluctuations on the discharge gap up to 3 kV simultaneously with it. In some experiments it was observed abrupt increase in the oscillation amplitude, which can be caused by the resonance of the acoustic oscillations in discharge chamber volume and the oscillations connected with alignment of the gaskinetic pressure and the magnetic pressure, as far as frequencies of these oscillations are close to each other in accordance with the estimates and the experimental data. Resonance of different type oscillations can produce energy density increasing in the discharge channel. Thus, the appropriate initial conditions in the experiment allow to increase the energy density in the discharge channel
Abstract: Vernacular building is considered as sustainable in
energy consumption and environment and its thermal performance is
more and more concerned by researchers. This paper investigates the
thermal property of the vernacular building in Lhasa by theoretical
analysis on the aspects of building form, envelope and materials etc.
The values of thermal resistance and thermal capacity of the envelope
are calculated and compared with the current China building code and
modern building case. And it is concluded that Lhasa vernacular
building meets the current China building code of thermal standards
and have better performance in some aspects, which is achieved by
various passive means with close response to local climate conditions.
Abstract: The kinetics of palm oil catalytic cracking over
aluminum containing mesoporous silica Al-MCM-41 (5% Al) was
investigated in a batch autoclave reactor at the temperatures range of
573 – 673 K. The catalyst was prepared by using sol-gel technique
and has been characterized by nitrogen adsorption and x-ray
diffraction methods. Surface area of 1276 m2/g with average pore
diameter of 2.54 nm and pore volume of 0.811 cm3/g was obtained.
The experimental catalytic cracking runs were conducted using 50 g
of oil and 1 g of catalyst. The reaction pressure was recorded at
different time intervals and the data were analyzed using Levenberg-
Marquardt (LM) algorithm using polymath software. The results
show that the reaction order was found to be -1.5 and activation
energy of 3200 J/gmol.
Abstract: In recent years various types of electric vehicles
has gained again increasing attention as an environmentally
benign technology in transport. Especially for urban areas with
high local pollution this Zero-emission technology (at the point
of use) is considered to provide proper solutions. Yet, the bad
economics and the limited driving ranges are still major barriers
for a broader market penetration of battery electric vehicles
(BEV) and of fuel cell vehicles (FCV). The major result of our
analyses is that the most important precondition for a further
dissemination of BEV in urban areas are emission-free zones.
This is an instrument which allows the promotion of BEV
without providing excessive subsidies. In addition, it is
important to note that the full benefits of EV can only be
harvested if the electricity used is produced from renewable
energy sources. That is to say, it has to be ensured that the use of
BEV in urban areas is clearly linked to a green electricity
purchase model. And moreover, the introduction of a CO2-
emission-based tax system would support this requirement.
Abstract: The steady incompressible flow has been solved in cylindrical coordinates in both vapour region and wick structure. The governing equations in vapour region are continuity, Navier-Stokes and energy equations. These equations have been solved using SIMPLE algorithm. For study of parameters variation on heat pipe operation, a benchmark has been chosen and the effect of changing one parameter has been analyzed when the others have been fixed.
Abstract: This paper is concerned with the numerical minimization
of energy functionals in BV (
) (the space of bounded variation
functions) involving total variation for gray-scale 1-dimensional inpainting
problem. Applications are shown by finite element method
and discontinuous Galerkin method for total variation minimization.
We include the numerical examples which show the different recovery
image by these two methods.
Abstract: Since large power transformers are the most
expensive and strategically important components of any power
generator and transmission system, their reliability is crucially
important for the energy system operation. Also, Circuit breakers are
very important elements in the power transmission line so monitoring
the events gives a knowledgebase to determine time to the next
maintenance. This paper deals with the introduction of the
comparative method of the state estimation of transformers and
Circuit breakers using continuous monitoring of voltage, current.
This paper gives details a new method based on wavelet to apparatus
insulation monitoring. In this paper to insulation monitoring of
transformer, a new method based on wavelet transformation and
neutral point analysis is proposed. Using the EMTP tools, fault in
transformer winding and the detailed transformer winding model
were simulated. The current of neutral point of winding was analyzed
by wavelet transformation. It is shown that the neutral current of the
transformer winding has useful information about fault in insulation
of the transformer.
Abstract: Rapid progress in process automation and tightening
quality standards result in a growing demand being placed on fault
detection and diagnostics methods to provide both speed and
reliability of motor quality testing. Doubly fed induction generators
are used mainly for wind energy conversion in MW power plants.
This paper presents a detection of an inter turn stator and an open
phase faults, in a doubly fed induction machine whose stator and
rotor are supplied by two pulse width modulation (PWM) inverters.
The method used in this article to detect these faults, is based on
Park-s Vector Approach, using a neural network.
Abstract: Bicycle usage for exercise, recreation, and commuting
to work in Australia shows that pedal cycling is the fourth most
popular activity with 10.6% increase in participants between 2001
and 2007. As with other means of transport, accident and injury
becomes common although mandatory bicycle helmet wearing has
been introduced. The research aims to develop a face surrogate made
of sandwich of rigid foam and rubber sheets to represent human
facial bone under blunt impact. The facial surrogate will serve as an
important test device for further development of facial-impact
protection for cyclist. A test procedure was developed to simulate the
energy of impact and record data to evaluate the effect of impact on
facial bones. Drop tests were performed to establish a suitable
combination of materials. It was found that the sandwich structure of
rigid extruded-polystyrene foam (density of 40 kg/m3 with a pattern
of 6-mm-holes), Neoprene rubber sponge, and Abrasaflex rubber
backing, had impact characteristics comparable to that of human
facial bone. In particular, the foam thickness of 30 mm and 25 mm
was found suitable to represent human zygoma (cheekbone) and
maxilla (upper-jaw bone), respectively.