theof measured data under sinusoidal excitation. Although the hysteresis models and loss separation approach can lead to satisfactory results, they require extensive computations and measurement works. Empirical approach enables loss determination with manufacturer-provided data with an easy way to use expression. The Impact of Perceived Privacy Breach on Sustainability of Social Networking Sites Nowadays, Steinmetz equation is widely used in the design of magnetic components in power converters, which expresses core loss density as power law with fixed exponent of frequency The Impact of Perceived Privacy Breach on Sustainability of Social Networking Sites and flux density where K, α, and β are constants provided by the manufacturer, and ΔB is the peak-to-peak flux density that can be obtained from Faraday’s law where N is the number of turns, Ae is the cross section of the core, means volt-seconds. However is only valid for sinusoidal waveform, and in some cases, loss for nonsinusoidal waveform can far exceed the loss due to sinusoidal ones, even when the frequencies and the peak flux densities are both equal. Reference has proven that core loss can lead to an error of up to in relation to the measured results for an H-bridge converter case operating with square waveform with zero-voltage period. In order to deal with any waveforms, some modified expressions including modified Steinmetz expression  MSE generalized Steinmetz equation  GSE improved GSE natural Steinmetz extension equivalent elliptical loop and waveform coefficient Steinmetz equation were introduced. A complete comparison among these modified empirical methods for a bidirectional isolation dc–dc converter shows that the MSE and the IGSE have the best loss determination; however, the IGSE copes better with a wide variety of voltage waveform  are determined by equating the loss expression for a sinusoidal excitation case with The anglerepresents the phase angle of the sinusoidal waveform. Applying a piecewise linear model  PWL to the nonsinusoidal waveform and then combining it with the IGSE leads to an easy-to-use expression for the determination of core loss. Furthermore, it is believed that the IGSE is the most practical method for calculating core loss with nonsinusoidal waveforms in most high-frequency magnetic design work, because it requires only readily available sinusoidal loss data, in the form of parameters for the Steinmetz equation characterizing the material. For the full-bridge dc–dc converter operating with the symmetrical square waveforms, a new extension of Steinmetz equation can be deduced based on the IGSE and the PWL model  where D is the switching duty cycle. Bsqm is the peak flux density when the square waveform is with duty cycle, which can be obtained from  According core loss can be determined by the number of turns, core cross section, excitation voltage, duty cycle, core volume, and material. The peak flux is inversely proportional with the frequency, and the exponent  is higher than the exponent α in general magnetic materials. The Impact of Perceived Privacy Breach on Sustainability of Social Networking Sites Therefore, core loss will decrease with increasing frequency. The frequency leads to a tradeoff between winding loss and core loss, because high frequency significantly increases ac resistance, as presented before. With increasing number of turns, core loss can be benefited from the lower peak flux density but sacrificing winding loss. The Impact of Perceived Privacy Breach on Sustainability of Social Networking Sites Using several cores to be cascaded to increase the core cross section can minimize the flux density, but it also increases winding loss, because an extra length of winding is added.

Study and analysis of Social network Aggregator

As seen in ac resistance is not only related to MMF ratio mbut also dependent on the ratio ξ.With a given frequency, the  minimal ac resistance can be determined by the layer thickness of windings. The choice of thickness as a physical parameter has been a key in optimizing PT. shows that the ratio of ac resistance to Study and analysis of Social network Aggregator dc resistance increases with increasing thickness at  a fixed frequency. For a largem, the proximity effect dominates over the skin effect, which leads to a higher winding resistance. With decreasing thickness of the conductor, the ratio is close to which represents a low eddy current effect in the conductor Study and analysis of Social network Aggregator, but the dc resistance will be increased.

Hereby, minimal ac resistances can be figured out for different MMF ratios m, as shown in Regarding the case that several number of turns are involved in a layer, the proximity effect among them in the horizontal direction can almost be negligible if the width is much more than the thickness; otherwise, the porosity factor η needs to be introduced As shown in the MMF ratio m is referred to be as small as possible, so that Study and analysis of Social network Aggregatora minimal ac resistance can be obtained. In fact, it is not practical in the middle frequency, because a relative thicker conductor needs to be used. The window space of the core is also a limitation on this issue. However, in high-frequency application above the MMF ratio m of can practically be implemented because of a very small skin depth. Parallel connection of multilayer for planar winding is now usually employed to increase the current handling capacity of the winding.

Study and analysis of Social network Aggregators

However, with parallel winding connections, the magnetic field around windings becomes more complicated. Due to the leakage fluxes and the high-frequency effects, the currents may not be equally shared among the paralleled layers. In other words, circulating currents may exist in parallel layers, which contributes to an extra winding loss. and  present the extra winding loss caused by “parallel effect loss” circulating currents in detail. Study and analysis of Social network Aggregator There are many limitations on the validity of such as the minimum distances between consecutive turns, between adjacent layers, and between the conductor edge and the magnetic core, as well as sinusoidal waveform. The most outstanding work as a calculation method of the ac resistance for any current waveform to correct Dowell’s assumptions can be found in  In addition, several publications also get generalized correction factors to be applied in Dowell’s resistance factor expression.

Study and analysis of Social network Aggregator However, these factors are usually derived from elaborated formulas and have to be determined from complicated coefficient tables Outside these minimum boundaries, it is advisable to determine Study and analysis of Social network Aggregator winding losses with FEA simulations. Referring to most of the literature, there are three main methods to deal with magnetic loss: hysteresis models; loss separation approach; and empirical methods. The former is usually based on the Jiles–Atherton or Preisach models The loss separation approach assumes that three fundamental effects are contributing to core losses: static hysteresis loss eddy current loss; Study and analysis of Social network Aggregator and excess eddy current loss Finally, the empirical approaches are based on the Steinmetz equation, which is a curve-fitting expression

SLA management and service composition of virtualized applications in mobile networking environments

Winding losses in transformers dramatically increase with high frequency due to eddy current effects. SLA management and service composition of virtualized applications in mobile networking environments For design and optimization of transformers, there is a need for an accurate prediction of the winding losses over a wide frequency range and for various winding arrangements. Eddy current losses including skin effect and proximity  effect losses, seriously impair the performance of transformers in high-frequency power conversion applications. For ac current flowing in a conductor, the alternating field inside this conductor induces eddy currents in the conductor, which produce a field that tends to cancel the field produced by the original current.

The tendency of the alternating current distributes itself within the conductor, so that the current density near the surface of the conductor is greater than that at its center. This is called skin effect, which causes the effective resistance of the conductor to increase with the frequency of the current. The proximity effect is similar, but it is caused by the current carried by an adjacent conductor. The current in the adjacent conductor causes a time-varying field and induces a circulating current inside the conductor. SLA management and service composition of virtualized applications in mobile networking environments Both the skin effect and the proximity effect cause the current density to be nonuniform inascddjkbff the cross section of the conductor and thus cause a higher winding resistance at higher frequency.

SLA management and service composition of virtualized applications in mobile networking environment

The skin effect of an infinite foil conductor with sinusoidal excitation can be represented by the ratio of ac resistance to dc resistance as in which describes the skin effect. In addition, the second term represents the proximity effect factor. The proximity effect loss, in a multilayer winding, may strongly dominate over the skin effect loss, depending on the value of m, which is related to the winding arrangement. Interleaving transformer windings can significantly reduce the proximity loss when the primary and secondary currents are in phase. shows the MMF distributions along the vertical direction for noninterleaving arrangement and fully interleaving arrangement, respectively. The value of m can be calculated according to and quite different results are also shown in In order to further illustrate the eddy current effect in different arrangements, a finite-element analysis FEA tool is used to analyze current distribution inside the conductors.and individually represent current distributions for interleaving windings and noninterleaving windings when the excitation frequency is PT model with cylindrical symmetry about the Z-axis has been built, and all of the conditions are the same in both figures, except the winding arrangement.

It can be seen from the two figures that current density is higher toward the symmetrical Z-axis due to the dc spirality effect. The skin and the proximity effects can further increase the nonuniform distribution of current density when the frequency goes high. In other words, the color division of current distribution is caused not only by the dc spirality effect but also by the skin and the proximity effects. It is noteworthy that ac resistance will not be contributed by the dc spirality effect. For the noninterleaving arrangement in, the tendency of current density toward conductor surface is enhanced due to higher proximity effect. SLA management and service composition of virtualized applications in mobile networking environments The strongest tendency toward conductor surface appears in the layer close to the interface between the primary and the secondary, and thus, the area of color division becomes smaller, which means that a higher ac resistance will be produced.

Usability study of mobile social networking system among Saudi Type diabetes patients SANAD

THE trend toward high power density, high operating frequency, and low profile in power converters has exposed a number of limitations in the use of conventional wirewound magnetic component structures. Usability study of mobile social networking system among Saudi Type diabetes patients SANAD In recent years, planar transformer PT has become increasingly popular in highfrequency power converters because of the unique advantages that they achieved in terms of low profile, excellent thermal characteristic, modularity and manufacturing simplicity, increased reliability, and power density The use of higher switching frequency can result in passive component size reduction, which achieves higher power density in power converter.

However, also for the conventional magnetic structures, the demand of high-frequency operation also causes a number of limitations in planar magnetic structures, such as the problem of increased losses due to the skin and theproximity effects, particularly at frequencies above 100 kHz. Regarding winding ac resistance, many efforts have been made to derive expressions allowing for an accurate representation of Usability study of mobile social networking system among Saudi Type diabetes patients SANAD frequency behavior of ac resistance. The ac resistance effects due to high-frequency current are specifically tailored for transformers by Dowell This work is based on a solution of the diffusion equation, as applied to conducting parallel plates. The expression for ac resistance has been rearranged in due to the squared porosity factor η.

Usability study of mobile social networking system among Saudi Type diabetes patients SANADs

The comparison of various methods for calculating the ac resistance of windings is given in The papers analyze and i Usability study of mobile social networking system among Saudi Type diabetes patients SANAD mprove the  ac resistance expression specifically for different situations. Based on Dowell’s equation, an optimum layer thickness of conductors minimizing winding loss can be found, which also significantly affects the leakage inductance, as shown in Regarding core loss, there are three main methods to calculate: hysteresis models loss separation approa empirical methods. The empirical approach enables loss determination with manufacturer-provided data with an easy way to use expression. The typical expression, i.e., the Steinmetz equation, is limited by some constraints, so that many publications focus on improving Steinmetz equation to extv Usability study of mobile social networking system among Saudi Type diabetes patients SANAD end its use In this paper, a detail analysis in winding loss, core loss, leakage inductance, and stray capacitance has been presented. The tradeoffs among these factors have to be analyzed in order to achieve an optimal design.

Furthermore, winding arrangements can, in part, bring an optimal behavior in the tradeoffs without any sacrifices, which play an important role in optimizing PT. Combining with an application in fullbridge dc–dc converter, Usability study of mobile social networking system among Saudi Type diabetes patients SANAD four different winding arrangements have been compared to illustrate each their merits and drawbacks. An improved interleaving structure P Usability study of mobile social networking system among Saudi Type diabetes patients SANAD is proposed, which constructs the top layer paralleling with the bottom layer and then in series with the other turns of the primary, so that a lower magnetomotive force MMF ratio m can be obtained, as well as minimized ac resistance, leakage inductance, and even stray capacitance. The detail experimental results have been shown in Section IV. Winding losses in transformers dramatically increase with high frequency due to eddy current effects. Usability study of mobile social networking system among Saudi Type diabetes patients SANAD For design and optimization of transformers, there is a need for an accurate prediction of the winding losses over a wide frequency range and for various winding arrangements. Usability study of mobile social networking system among Saudi Type diabetes patients SANAD Eddy current losses.