Abstract: Heat transfer through multiple pane windows can be reduced by creating a vacuum pressure less than 0.1 Pa between the glass panes, with low emittance coatings on one or more of the internal surfaces. Fabrication of vacuum glazing (VG) requires the formation of a hermetic seal around the periphery of the glass panes together with an array of support pillars between the panes to prevent them from touching under atmospheric pressure. Atmospheric pressure and temperature differentials induce stress which can affect the integrity of the glazing. Several parameters define the stresses in VG including the glass thickness, pillar specifications, glazing dimensions and edge seal configuration. Inherent stresses in VG can result in fractures in the glass panes and failure of the edge seal. In this study, stress in VG with different glass thicknesses is theoretically studied using Finite Element Modelling (FEM). Based on the finding in this study, suggestions are made to address problems resulting from the use of thinner glass panes in the fabrication of VG. This can lead to the development of high performance, light and thin VG.
Abstract: Strain sensors based on a change in resistance are
well established for the measurement of forces, stresses, or material
fatigue. Within the scope of this paper, fully additive manufactured
strain sensors were produced using an ink of silver nanoparticles.
Their behavior was evaluated by periodic tensile tests. Printed
strain sensors exhibit two advantages: Their measuring grid is
adaptable to the use case and they do not need a carrier-foil,
as the measuring structure can be printed directly onto a thin
sprayed varnish layer on the aluminum specimen. In order to
compare quality characteristics, the sensors have been manufactured
using two different technologies, namely aerosoljet-printing and
micropipette-dispensing. Both processes produce structures which
exhibit continuous features (in contrast to what can be achieved with
droplets during inkjet printing). Briefly summarized the results show
that aerosoljet-printing is the preferable technology for specimen with
non-planar surfaces whereas both technologies are suitable for flat
Abstract: Low ink sintering temperature is desired for flexible electronics, as it would widen the application of the ink on temperature-sensitive substrates where the selection of silver precursor is very critical. In this paper, four types of organic silver precursors, silver carbonate, silver oxalate, silver tartrate and silver itaconate, were synthesized using an ion exchange method, firstly. Various characterization methods were employed to investigate their physical phase, chemical composition, morphologies and thermal decomposition behavior. It was found that silver oxalate had the ideal thermal property and showed the lowest decomposition temperature. An ink was then formulated by complexing the as-prepared silver oxalate with ethylenediamine in organic solvents. Results show that a favorable conductive film with a uniform surface structure consisting of silver nanoparticles and few voids could be produced from the ink at a sintering temperature of 150 °C.
Abstract: The three phase system drives produce the problem of more torque pulsations and harmonics. This issue prevents the smooth operation of the drives and it also induces the amount of heat generated thus resulting in an increase in power loss. Higher phase system offers smooth operation of the machines with greater power capacity. Five phase variable-speed induction motor drives are commonly used in various industrial and commercial applications like tractions, electrical vehicles, ship propulsions and conveyor belt drive system. In this work, a comparative analysis of the different modulation schemes applied on the five-level five-phase Packed U Cell (PUC) inverter fed induction motor drives is presented. The performance of the inverter is greatly affected with the modulation schemes applied. The system is modeled, designed, and implemented in MATLAB®/Simulink environment. Experimental validation is done for the prototype of single phase, whereas five phase experimental validation is proposed in the future works.
Abstract: Analysis of fire data is a way for the implementation of any plan to improve the level of safety in cities. Such an analysis is able to reveal signs of changes in a given period and can be used as a measure of safety. The information of about 66,341 fires (from 2002 to 2012) released by Tehran Safety Services and Fire-Fighting Organization and data on the population and the number of households provided by Tehran Municipality and the Statistical Yearbook of Iran were extracted. Using the data, the fire changes, the rate of injuries, and mortality rate were determined and analyzed. The rate of injuries and mortality rate of fires per one million population of Tehran were 59.58% and 86.12%, respectively. During the study period, the number of fires and fire stations increased by 104.38% and 102.63%, respectively. Most fires (9.21%) happened in the 4th District of Tehran. The results showed that the recorded fire data have not been systematically planned for fire prevention since one of the ways to reduce injuries caused by fires is to develop a systematic plan for necessary actions in emergency situations. To determine a reliable source for fire prevention, the stages, definitions of working processes and the cause and effect chains should be considered. Therefore, a comprehensive statistical system should be developed for reported and recorded fire data.
Abstract: Cartesian Genetic Programming (CGP) is explored to
design an optimal circuit capable of early stage breast cancer
detection. CGP is used to evolve simple multiplexer circuits for
detection of malignancy in the Fine Needle Aspiration (FNA) samples
of breast. The data set used is extracted from Wisconsins Breast
Cancer Database (WBCD). A range of experiments were performed,
each with different set of network parameters. The best evolved
network detected malignancy with an accuracy of 99.14%, which is
higher than that produced with most of the contemporary non-linear
techniques that are computational expensive than the proposed
system. The evolved network comprises of simple multiplexers
and can be implemented easily in hardware without any further
complications or inaccuracy, being the digital circuit.
Abstract: Wind energy is associated with many geographical factors including wind speed, climate change, surface topography, environmental impacts, and several economic factors, most notably the advancement of wind technology and energy prices. It is the fastest-growing and least economically expensive method for generating electricity. Wind energy generation is directly related to the characteristics of spatial wind. Therefore, the feasibility study for the wind energy conversion system is based on the value of the energy obtained relative to the initial investment and the cost of operation and maintenance. In Kuwait, wind energy is an appropriate choice as a source of energy generation. It can be used in groundwater extraction in agricultural areas such as Al-Abdali in the north and Al-Wafra in the south, or in fresh and brackish groundwater fields or remote and isolated locations such as border areas and projects away from conventional power electricity services, to take advantage of alternative energy, reduce pollutants, and reduce energy production costs. The study covers the State of Kuwait with an exception of metropolitan area. Climatic data were attained through the readings of eight distributed monitoring stations affiliated with Kuwait Institute for Scientific Research (KISR). The data were used to assess the daily, monthly, quarterly, and annual available wind energy accessible for utilization. The researchers applied the Suitability Model to analyze the study by using the ArcGIS program. It is a model of spatial analysis that compares more than one location based on grading weights to choose the most suitable one. The study criteria are: the average annual wind speed, land use, topography of land, distance from the main road networks, urban areas. According to the previous criteria, the four proposed locations to establish wind farm projects are selected based on the weights of the degree of suitability (excellent, good, average, and poor). The percentage of areas that represents the most suitable locations with an excellent rank (4) is 8% of Kuwait’s area. It is relatively distributed as follows: Al-Shqaya, Al-Dabdeba, Al-Salmi (5.22%), Al-Abdali (1.22%), Umm al-Hayman (0.70%), North Wafra and Al-Shaqeeq (0.86%). The study recommends to decision-makers to consider the proposed location (No.1), (Al-Shqaya, Al-Dabdaba, and Al-Salmi) as the most suitable location for future development of wind farms in Kuwait, this location is economically feasible.
Abstract: This paper presents an optimization method based
on genetic algorithm for the energy management inside buildings
developed in the frame of the project Smart Living Lab (SLL)
in Fribourg (Switzerland). This algorithm optimizes the interaction
between renewable energy production, storage systems and energy
consumers. In comparison with standard algorithms, the innovative
aspect of this project is the extension of the smart regulation
over three simultaneous criteria: the energy self-consumption, the
decrease of greenhouse gas emissions and operating costs. The
genetic algorithm approach was chosen due to the large quantity
of optimization variables and the non-linearity of the optimization
function. The optimization process includes also real time data of the
building as well as weather forecast and users habits. This information
is used by a physical model of the building energy resources to predict
the future energy production and needs, to select the best energetic
strategy, to combine production or storage of energy in order to
guarantee the demand of electrical and thermal energy. The principle
of operation of the algorithm as well as typical output example of
the algorithm is presented.
Abstract: The paper presents the impact of work on the electric arc furnace. Arc equipment is one of the largest receivers powered by the power system. Electric arc disturbances arising during melting process occurring in these furnaces are the cause of an abrupt change of the passive power of furnaces. Currents drawn by these devices undergo an abrupt change, which in turn cause voltage fluctuations and light flicker. The quantitative evaluation of the voltage fluctuations is now the basic criterion of assessment of an influence of unquiet receiver on the supplying net. The paper presents the method of determination of range of voltage fluctuations and light flicker at parallel operation of arc devices. The results of measurements of voltage fluctuations and light flicker indicators recorded in power supply networks of steelworks were presented, with different number of parallel arc devices. Measurements of energy quality parameters were aimed at verifying the proposed method in practice. It was also analyzed changes in other parameters of electricity: the content of higher harmonics, asymmetry, voltage dips.
Abstract: This paper presents a comparative study of the Gauss Seidel and Newton-Raphson polar coordinates methods for power flow analysis. The effectiveness of these methods are evaluated and tested through a different IEEE bus test system on the basis of number of iteration, computational time, tolerance value and convergence.
Abstract: This paper presents a thirteen-level asymmetrical
cascaded H-bridge single phase inverter. In this configuration, the
desired output voltage level is achieved by connecting the DC sources in
different combinations by triggering the switches. The modes of
operation are explained well for positive level generations. Moreover, a
comparison is made with conventional topologies of diode clamped,
flying capacitors and cascaded-H-bridge and some recently proposed
topologies to show the significance of the proposed topology in terms of
reduced part counts. The simulation work has been carried out in
MATLAB/Simulink environment. The experimental work is also carried
out for lower rating to verify the performance and feasibility of the
proposed topology. Further the results are presented for different loading
Abstract: Focus on reducing energy consumption in existing
buildings at large scale, e.g. in cities or countries, has been
increasing in recent years. In order to reduce energy consumption
in existing buildings, political incentive schemes are put in place and
large scale investments are made by utility companies. Prioritising
these investments requires a comprehensive overview of the energy
consumption in the existing building stock, as well as potential
energy-savings. However, a building stock comprises thousands
of buildings with different characteristics making it difficult to
model energy consumption accurately. Moreover, the complexity of
the building stock makes it difficult to convey model results to
policymakers and other stakeholders. In order to manage the complexity of the building stock, building
archetypes are often employed in building stock energy models
(BSEMs). Building archetypes are formed by segmenting the building
stock according to specific characteristics. Segmenting the building
stock according to building type and building age is common, among
other things because this information is often easily available. This
segmentation makes it easy to convey results to non-experts. However, using a single archetypical building to represent all
buildings in a segment of the building stock is associated with
loss of detail. Thermal characteristics are aggregated while other
characteristics, which could affect the energy efficiency of a building,
are disregarded. Thus, using a simplified representation of the
building stock could come at the expense of the accuracy of the
model. The present study evaluates the accuracy of a conventional
archetype-based BSEM that segments the building stock according
to building type- and age. The accuracy is evaluated in terms of the
archetypes’ ability to accurately emulate the average energy demands
of the corresponding buildings they were meant to represent. This is
done for the buildings’ energy demands as a whole as well as for
relevant sub-demands. Both are evaluated in relation to the type- and
the age of the building. This should provide researchers, who use
archetypes in BSEMs, with an indication of the expected accuracy
of the conventional archetype model, as well as the accuracy lost in
specific parts of the calculation, due to use of the archetype method.
Abstract: This paper presents parameter estimation of a
single-phase rectifier using extended Kalman filter (EKF). The state
space model has been obtained using Kirchhoff’s current law (KCL)
and Kirchhoff’s voltage law (KVL). The capacitor voltage and diode
current of the circuit have been estimated using EKF. Simulation
results validate the better accuracy of the proposed method as
compared to the least mean square method (LMS). Further, EKF
has the advantage that it can be used for nonlinear systems.
Abstract: In this paper we present a contribution for the modeling and control of wind energy conversion system based on a Doubly Fed Induction Generator (DFIG). Since the wind speed is random the system has to produce an optimal electrical power to the Network and ensures important strength and stability. In this work, the Backstepping controller is used to control the generator via two converter witch placed a DC bus capacitor and connected to the grid by a Filter R-L, in order to optimize capture wind energy. All is simulated and presented under MATLAB/Simulink Software to show performance and robustness of the proposed controller.
Abstract: An electrical generator able to harness energy from the water waves and designed as a double-cone geared motor-generator (DCGMG), is proposed and theoretically investigated. Similar to a differential gear mechanism, used in the transmission system of the auto vehicle wheels, an angular speed differential is created between the cones rolling on two concentric circular rails. Water wave acting on the floating DCGMG produces and a gear-box amplifies the speed differential to gain sufficient torque for power generation. A model that allows computation of the speed differential, torque, and power of the DCGMG is suggested. Influence of various parameters, regarding the construction of the DCGMG, as well as the contact between the double-cone and rails, on the electro-mechanical output, is emphasized. Results obtained indicate that the generated electrical power can be increased by augmenting the mass of the double-cone, the span of the rails, the apex angle of the cones, the friction between cones and rails, the amplification factor of the gear-box, and the efficiency of the motor-generator. Such findings are useful to formulate a design methodology for the proposed wave-powered generator.
Abstract: With the spread of EVs (electric Vehicles), the ride
comfort has been gaining a lot of attention. The influence of the lateral
acceleration is important for the improvement of ride comfort of EVs
as well as the longitudinal acceleration, especially upon turning of
the vehicle. Therefore, this paper proposes a practical optimal speed
control method to greatly improve the ride comfort in the vehicle
turning situation. For consturcting this method, effective criteria that
can appropriately evaluate deterioration of ride comfort is derived.
The method can reduce the influence of both the longitudinal and
the lateral speed changes for providing a confortable ride. From
several simulation results, we can see the fact that the method can
prevent aggravation of the ride comfort by suppressing the influence
of longitudinal speed change in the turning situation. Hence, the
effectiveness of the method is recognized.