Optimal Combination of Solar Energy and Diesel Fuel in a System Used in Remote Areas

Regarding importance of security and safety in all countries around the world, the work of the security men requires the use of all means of communication wired or wireless to surveillance and monitor the security situation around the clock. So, there are remote sites belonging to the Ministry of the Interior such as deserts, mountains and maritime islands takes a long time to arrive to it after trouble and hardship. At those locations, towers and communication devices working on generators that work by diesel but the main problem is the sudden interruption for these generators causing disrupted communication devices. And the period of interruption may be an opportunity for intruder to entry across borders or for terrorist person in carrying out his plans. So, we had to resort to renewable energy for a stable and sustainable energy working permanently to nurture communication devices while backup generators in case of a defect in a renewable energy system.Through the renewable energy will decrease many problems including sudden interruption of communication devices that may cause security problems, reducing the cost of fuel, the cost of spare parts. The research interested in using optimal combination of solar energy and diesel fuel in a system used in remote areas, the system can provide the electrical power all time without any trip because it works in completed way when the diesel fuel ends the system will use the electrical power which produced by solar energy in automatically. Keywords: Simulation, Optimal combination, solar energy, diesel fuel and remote areas

Investigating The Effect of Switching and tripping on Flashover and Breakdown in Circuit Breaker

The need for electrical power is increasing rapidly. The power is transmitted over long distance that made it establish to use high voltage .this need to created circuit breaker. Are an essential part of power system and it plays a major role in study and control. Circuit breaker use SF6 gas circuit breaker as insulation medium. The paper interested in study the SF6 gas circuit breaker; characteristics and advantages and how to deal with it, The paper interested in investigating the effect of switching, tripping on flashover and breakdown on SF6 gas circuit breaker. It shows the main factors which that effected in the SF6 gas circuit breaker performance and which caused faults flashover and tripping. The factors that caused faults may be from the circuit breaker itself or may be related with any part from circuit breaker such as transmission line location. Keywords: SF6 gas circuit breaker, circuit breaker, transmission line, location and moisture

Off-line handwritten signature recognition by wavelet entropy and neural network

Handwritten signatures are widely utilized as a form of personal recognition. However, they have the unfortunate shortcoming of being easily abused by those who would fake the identification or intent of an individual which might be very harmful. Therefore, the need for an automatic signature recognition system is crucial. In this paper, a signature recognition approach based on a probabilistic neural network (PNN) and wavelet transform average framing entropy (AFE) is proposed. The system was tested with a wavelet packet (WP) entropy denoted as a WP entropy neural network system (WPENN) and with a discrete wavelet transform (DWT) entropy denoted as a DWT entropy neural network system (DWENN). Our investigation was conducted over several wavelet families and different entropy types. Identification tasks, as well as verification tasks, were investigated for a comprehensive signature system study. Several other methods used in the literature were considered for comparison. Two databases were used for algorithm testing. The best recognition rate result was achieved by WPENN whereby the threshold entropy reached 92%

230 s room-temperature storage time and 1.14 eV hole localization energy in In0.5Ga0.5As quantum dots on a GaAs interlayer in GaP with an AlP barrier

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 106, 042102 (2015) and may be found at https://doi.org/10.1063/1.4906994.A GaP n+p-diode containing In0.5Ga0.5As quantum dots (QDs) and an AlP barrier is characterized electrically, together with two reference samples: a simple n+p-diode and an n+p-diode with AlP barrier. Localization energy, capture cross-section, and storage time for holes in the QDs are determined using deep-level transient spectroscopy. The localization energy is 1.14(±0.04) eV, yielding a storage time at room temperature of 230(±60) s, which marks an improvement of 2 orders of magnitude compared to the former record value in QDs. Alternative material systems are proposed for still higher localization energies and longer storage times

Space charge behaviour in epoxy laminates under high constant electric field

The development of space charge in insulating materials is one of the main causes of their electrical ageing. The pulsed electro-acoustic method is often used to determine space charge distribution, but the signal analysis in the case of laminate structures is much more complex to analyse. In this paper the authors describe and use a simulated signal in order to study laminates made of epoxy resin and fibre mat. The relatively large conductivity of the fibres compared with that of the resin seems to produce a rapid charge dissociation and recombination in the fibres. Under voltage the presence of fibres close to an electrode seems to promote charge injection

Room-Temperature Hysteresis in a Hole-Based Quantum Dot Memory Structure

We demonstrate a memory effect in self-assembled InAs/Al0.9Ga0.1As quantum dots (QDs) near room temperature. The QD layer is embedded into a modulation-doped field-effect transistor (MODFET) which allows to charge and discharge the QDs and read out the logic state of the QDs. The hole storage times in the QDs decrease from seconds at 200 K down to milliseconds at room temperature

Darcy flow and heat transfer of nanoliquid within a porous annulus with incorporating magnetic terms

Current investigation was carried out to analyze the treatment of nanomaterial within a domain which experienced magnetic force. Outer rhombus wall is cold and the inner circle has uniform heat flux and due to these conditions, carrier fluid rotates counterclockwise. Darcy law was used for simulation and Joule heating was neglected in equations. Influences of parameters were discussed in plots and contours and CVFEM has been employed to reach such outputs. Rotational core becomes stronger with the rise of Ra while opposite results have been accomplished with the soar of Ha. In cases with higher values of shape factor, Nu has higher values and a similar trend is reported for Rd. Moreover, Nu experiences 30% reduction when Ha augments. This negative impact becomes more sensible when radiation terms are added in equations. Inclusion of nano powders has a favorable impact on Nu although it has a negative impact on temperature gradient

The effect of high voltage fields on epoxy laminates

This thesis describes the characterisation of epoxy/glass fibre composite material before and progressively through electrical and thermal ageing. Glass fibre reinforced epoxy (GFRE) material is used in pressboard transformers for optical telecommunication systems, typically at voltages between 1 and 2kV. The material was characterised by means of space charge measurements using the Pulsed Electroacoustic (PEA) technique, Dielectric response, Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC), and Scanning Electronic Microscopy (SEM). An ageing programme was set up to follow the thermal and electrical ageing (at DC fields) of the GFRE by the same means. The results show a q-dc transport process with an activation energy of 1.1eV. The qdc process is associated with a charge transport process on the surface of the fibres. The results for the aged samples show delamination and debonding between the epoxy and the glass fibre at the glass epoxy interface. The delamination creates free volumes and voids which lead to partial discharge and hence failure. Electrical ageing can be characterised in term of dielectric, PEA, and DSC responses. Thermal ageing does not produce the same effect as electrical ageing. The samples that were only thermally aged behave in the same way as un-aged samples

The Use of LPC and Wavelet Transform for Influenza Disease Modeling

In this paper, we investigated the modeling of the pathological features of the influenza disease on the human speech. The presented work is novel research based on a real database and a new combination of previously used methods, discrete wavelet transform (DWT) and linear prediction coding (LPC). Three verification system experiments, Normal/Influenza, Smokers/Influenza, and Normal/Smokers, were studied. For testing the proposed pathological system, several classification scores were calculated for the recorded database, from which we can see that the proposed method achieved very high scores, particularly for the Normal with Influenza verification system. The performance of the proposed system was also compared with other published recognition systems. The experiments of these schemes show that the proposed method is superior

'Sub-Hertz' Dielectric Spectroscopy

Dielectric spectroscopy measurements below 1 Hz are often dominated by “conduction-like” effects. For this reason, they often appear to be dismissed as being of little interest. In this paper two “sub-hertz” responses are considered that give insights into the insulating sys-tems concerned. The first system is that of cross-linked polyethylene, taken from a power cable system. Measurements at temperatures between 60°C and close to melting at 100°C show a change in characteristic from a percolation process to a “true” DC conduction at close to the melting point. Using DC conductivities, it appears to be possible to show whether the cable has been subjected to thermo-electric ageing. This might give insights into where the conduction and hence the ageing in the XLPE is occurring. The second system is an epoxy composite. By considering the sub-hertz response, it is possible to demonstrate the effect of the interface between the filler and the epoxy matrix. In this system, ageing, resulting in delamination between the glass fiber filler and the epoxy, is clearly detected by sub-hertz dielectric spectroscopy. This process is likely to be facilitated by the presence of water, which is known to lead to mechanical failure in such systems, and which can also be detected by "sub-hertz" dielectric spectroscopy. The implications for nano-dielectrics are then briefly considered