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This paper proposes a physical charge-based analytical MOSFET threshold voltage model that explicitly incorporates interface-trapped charges which have been identified as playing a dominant role in defining threshold voltage trends in deep cryogenic temperatures. The model retains standard threshold voltage definition by various charges across the MOSFET capacitor while being analytical in its form, therefore, suitable for cryogenic CMOS VLSI design. Consequently, a model covering each and all above characteristics is proposed for the first time. Excellent fit between the model and measurement data from 180-nm bulk foundry devices is shown from room temperature to 4 K.

This article presents the novel structure of an eddy current sensor for linear speed measurements. The sensor has one excitation coil and two pairs of antiserially connected pick-up coils, which are located inside and outside the excitation coil. The design and modeling of the sensor are considered with an air core and with a magnetic yoke (core) to compare their performances in terms of sensitivity and nonlinearity error. The experiments and the analysis are performed at different excitation frequencies and speeds. A novel three-dimensional analytical method is developed and utilized for parametric analysis and for the design of this sensor. The simulation results are compared with measurements up to 16.7 m/s (60 km/h). The achieved nonlinearity error is as low as 0.3%. [ABSTRACT FROM AUTHOR]

Smart distribution grid with multiple renewable energy sources can experience random voltage fluctuations due to variable generation, which may result in voltage violations. Traditional voltage control algorithms are inadequate to handle fast voltage variations. Therefore, new dynamic control methods are being developed that can significantly benefit from the knowledge of dominant voltage influencer (DVI) nodes. DVI nodes for a particular node of interest refer to nodes that have a relatively high impact on the voltage fluctuations at that node. Conventional power flow-based algorithms to identify DVI nodes are computationally complex, which limits their use in real-time applications. This paper proposes a novel information theoretic voltage influencing score (VIS) that quantifies the voltage influencing capacity of nodes with DERs/active loads in a three phase unbalanced distribution system. VIS is then employed to rank the nodes and identify the DVI set. VIS is derived analytically in a computationally efficient manner and its efficacy to identify DVI nodes is validated using the IEEE 37-node test system. It is shown through experiments that KL divergence and Bhattacharyya distance are effective indicators of DVI nodes with an identifying accuracy of more than 90%. The computation burden is also reduced by an order of 5, thus providing the foundation for efficient voltage control. [ABSTRACT FROM AUTHOR]

This article presents a novel configuration of the eddy current speed sensor to measure the rotating speed of iron rods and shafts up to 3000 r/min. The proposed eddy current speed sensor has an axial airgap structure with one excitation coil and two antiserially connected pick up coils. The speed sensor is mounted in the end shaft part region. Different solid iron materials for rotating shaft are considered in the measurements and calculations to evaluate solid iron material effect on the eddy current speed sensor performance. Two-dimensional (2-D) and 3-D finite element method is utilized for the performance analysis of the speed sensor. Also, a 2-D analytical method is developed for parametric analysis. A copper rod is also used to compare the speed sensor with the rotating iron shaft and copper shaft. Finally, two thin copper discs with different diameters are mounted on the solid iron shaft and their influences on the eddy current speed sensor were evaluated and measured to increase sensitivity and decrease sensor dependency on the permeability of the solid iron shaft. The achieved nonlinearity errors are about ±0.2%. [ABSTRACT FROM AUTHOR]

In this paper, a generalized analytical approach is introduced to study the random crosstalk in multicore/multimode fibers. The proposed method is based on the stochastic differential equations (SDEs) for the coupled modal power as well as the coupled power covariance. While the existing analytical formulas for the inter-core/mode crosstalk are accurate in the weakly coupled regime, the proposed analytical tool is exact both in the weakly coupled regime and the strongly coupled regime. In addition to that, the proposed analytical method can compute the covariance of the modal power which is beyond the existing methods. Asymptotic behaviors of the power transfer matrix and the power covariance transfer matrix are discussed. [ABSTRACT FROM AUTHOR]

In this article, an electrodynamic suspension (EDS) maglev scheme with a novel coil topology named traveling magnetic electromagnetic Halbach array (TMEHA) is proposed and investigated in which thrust and lift forces are simultaneously created above a conductive flat guideway. First, the topological structure and principle of the TMEHA-EDS is introduced. Then the effectiveness of the TMEHA is analyzed qualitatively according to the analytic model based on harmonic analytical theory. Third, the 2-D analytical model of the TMEHA-EDS is proposed, and the thrust, lift force, efficiency, and the lift-to-weight ratio of the TMEHA-EDS are analyzed. Finally, a TMEHA-EDS prototype is manufactured, and experiments are carried out to verify the predicted results. [ABSTRACT FROM AUTHOR]

Due to the bidirectional field modulated effect, the dual-permanent-magnet-excited (DPME) machine relies on the countless airgap flux density harmonics with specific pole-pair numbers (PPNs) to produce stable torque or effective back electromotive force (EMF). Regarding the generation of back EMF, there is no doubt that the flux density harmonics which make a negative contribution will reduce the performance of DPME machine. However, to the best of our knowledge, there is very little research on the identification of field harmonics which play a negative role in the generation of back EMF. In this article, the partial-analytical-method (PAM) is proposed to quantitatively identify the field harmonics. First, the PAM is described in detail, and the ratio of contribution (RoC) is defined to assess the contribution of field harmonics to back EMF. Then, the PAM is applied to a 12/10 DPME machine. The identification results show that two of the five types of field harmonics, i.e., Type-II and Type-V, make a negative contribution to back EMF; the RoCs of which are −2.94% and −4.32%, respectively. In these two types of harmonics, the ones with PPN = 22 are mainly responsible for the negative contribution to back EMF, which needs attention at the outset of the design. [ABSTRACT FROM AUTHOR]

The critical nature of vehicular communications requires their extensive testing and evaluation. Analytical models can represent an attractive and cost-effective approach for such evaluation if they can adequately model all underlying effects that impact the performance of vehicular communications. Several analytical models have been proposed to date to model vehicular communications based on the IEEE 802.11p (or DSRC) standard. However, existing models normally model in detail the MAC (Medium Access Control), and generally simplify the propagation and interference effects. This reduces their value as an alternative to evaluate the performance of vehicular communications. This paper addresses this gap, and presents new analytical models that accurately model the performance of vehicle-to-vehicle communications based on the IEEE 802.11p standard. The models jointly account for a detailed modeling of the propagation and interference effects, as well as the impact of the hidden terminal problem. The model quantifies the PDR (Packet Delivery Ratio) as a function of the distance between transmitter and receiver. The paper also presents new analytical models to quantify the probability of the four different types of packet errors in IEEE 802.11p. In addition, the paper presents the first analytical model capable to accurately estimate the Channel Busy Ratio (CBR) metric even under high channel load levels. All the analytical models are validated by means of simulation for a wide range of parameters, including traffic densities, packet transmission frequencies, transmission power levels, data rates and packet sizes. An implementation of the models is provided openly to facilitate their use by the community. [ABSTRACT FROM AUTHOR]

Currently, there are no analytical formulas or ordinary differential equations (ODEs) to investigate the higher order statistics for the gain variations in fiber parametric amplifiers (FOPAs) with dispersion fluctuation. This is mainly due to the tedious efforts to derive the related ODEs. In this article, a comprehensive generalized stochastic coupled mode equation approach for the ODE derivation is proposed to study the gain variations in FOPAs, which greatly simplifies the derivation process. Based on the systematic approach, one may find the higher order statistics of the FOPA gain without the time consuming Monte Carlo simulations. The analytical and numerical solutions of the ODEs agree well with the Monte Carlo simulations. The approach can be extended to other practical problems like the higher order statistics of the mode amplitudes in the multimode fibers with random coupling. [ABSTRACT FROM AUTHOR]

This article presents an analytical model to reproduce the I-V characteristics of a double-gate (DG) amorphous indium–gallium–zinc oxide (a-IGZO) TFT with symmetric structure. This model for the above-threshold region is based on the gate voltage dependence of surface potential and potential at the center of the semiconductor layer, which are described by analytical expressions. Considering the densities of the free and localized carrier in the semiconductor, the total carrier density, which is equal to the effective carrier density, is calculated. The carrier mobility, calculated as the ratio between the free carrier and the effective carrier density, depends on the gate voltage as a power law with the power parameter γ different from zero, as it is typically represented for the amorphous TFT. The drain current model has only 13 model parameters and was validated with six different simulated transistor structures, as well as with an experimental device. A good coincidence of the modeled characteristics with both the simulated and experimental devices was obtained. [ABSTRACT FROM AUTHOR]

In several papers, analytical calculations of the mean value of the end-to-end delay in highway vehicular ad-hoc networks (VANETs) have been presented. Unfortunately, none of these papers presented calculations of the probability distribution of this delay, which is necessary to give probabilistically guaranteed upper bounds on the end-to-end delay in such VANETs. In a previous paper, we introduced the first analytical framework for the calculation of the probability distribution, and not only the mean, of the end-to-end delay in multi-lane one-way highway VANETs. This made it possible to provide guarantees of transmission in a given time frame with known confidence. In this paper, that previous work is extended to two-way multi-lane highways by taking into consideration vehicles travelling in both directions. The probability distribution of the end-to-end delay is calculated herein and its dependence on system parameters, such as speed distributions in the two directions, communication range, and vehicle densities, are analyzed. Computer simulations are used to verify the analytical model. The good agreement between simulation results and the analytical calculations demonstrates the correctness and accuracy of the proposed analytical model.

In this article, a new modeling approach is proposed to investigate cogging torque and the corresponding reduction techniques of flux-switching permanent magnet (FSPM) machines. First, based on the superposition of each single rotor tooth, an analytical expression of cogging torque in FSPM machines is derived and confirmed by the finite-element analysis (FEA). Then, three feasible techniques, i.e., successively shifting rotor teeth, alternately shifting rotor teeth, and stepped skewing rotor blocks, are proposed for cogging torque minimization of FSPM machines. Correspondingly, generally analytical expressions of these three methods are deduced, through which the analytically optimal shifting angles can be determined. Besides, the cogging torque harmonics are analyzed by both analytical expressions and FEA, and then, the multidimensional techniques, namely three rotor-based reduction methods combined with the optimal stator tooth width, are introduced and studied to further suppress cogging torque. Finally, prototyped machines are manufactured and tested, and the corresponding experiments verify the effectiveness of the reduction methods. [ABSTRACT FROM AUTHOR]

This paper proposes the analytical design methods of axial flux-switching permanent magnet (AxFSPM) machines. The analytical design methods take the influences of electric and magnetic loadings into account to calculate the specific sizing and scalability of the AxFSPM machine. In addition, the winding functions are implemented to derive the self-, mutual-, d-axis, and q-axis inductances. The results of analytical design methods indicate that the magnetic loading has bigger impact on the stator dimensions of AxFSPM machines than the electrical loading. The d- and q-axis inductances of the all-pole-wound AxFSPM machines are similar under the same number of slots and turns. A prototype is manufactured using analytical design methods. The experimental results show that the prototype machine achieves target specification and the usefulness of the proposed design method is verified. [ABSTRACT FROM AUTHOR]

In this paper, the back-electromotive force (back-EMF) characteristics of the flux-reversal permanent magnet (FRPM) machines with different magnetization methods and winding layouts are analyzed and synthesized based on the magneto motive force (MMF)-permeance model. The air gap field modulation theory is utilized to investigate the permanent magnet-MMF harmonics and open-circuit air gap flux density harmonics that make a contribution to back-EMF as well as its harmonics. Based on this analysis, the specific harmonic of back-EMF can be reduced by suppressing the corresponding PM-MMF harmonic. Besides, the influence of rotor pole number on back-EMF is also studied. It is found that with the aid of this modulation theory, the reasonable magnetization method, winding layout, and rotor pole number can be obtained to improve the back-EMF characteristics of an FRPM machine with an arbitrary slot/pole combination. Furthermore, prototype machines are manufactured and tested to verify the analytical predictions. [ABSTRACT FROM AUTHOR]

An analytical output force model is proposed for noncontact Lorentz force actuators (NLFAs), which are used for positioning and vibration isolation control of space sensitive loads that require an extremely quiet environment. A biaxial NLFA is presented. The actuator mainly consists of a closed magnetic circuit and a novel biaxial exciting circuit board developed by printed circuit board technology. The closed magnetic circuit consists of a C-type yoke and two permanent magnets and is simplified by the magnetic image method. A model of the spatial magnetic flux density in the air gap of the simplified closed magnetic circuit model is derived by the Ampere molecular current hypothesis and the Biot–Savart law. Finally, an analytical output force model of the actuator is obtained by calculating the magnetic flux densities and forces at selected finite points by considering the winding of the coils. The influences of the key dimensional parameters of the actuator on the output forces and their variations are studied using the derived analytical model. To verify the derived analytical model, a measurement setup is established based on an electronic scale. The experimental results show that the forces calculated by the proposed analytical model agree with the experimental values very well, and the deviation between the results is less than 4% when a rated force of 3 N is produced. Moreover, the relation between the number of selected points and computing time and the relation between the number of selected points and the extra calculation deviation, which are important for real-time control, are discussed. The proposed analytical model can help to improve the design efficiency and output force control of this kind of actuator. [ABSTRACT FROM AUTHOR]

The C-V2X or LTE-V standard has been designed to support vehicle to everything (V2X) communications. The standard is an evolution of LTE, and it has been published by the 3GPP in Release 14. This new standard introduces the C-V2X or LTE-V Mode 4 that is specifically designed for V2V communications using the PC5 sidelink interface without any cellular infrastructure support. In Mode 4, vehicles autonomously select and manage their radio resources. Mode 4 is highly relevant since V2V safety applications cannot depend on the availability of infrastructure-based cellular coverage. This paper presents the first analytical models of the communication performance of C-V2X or LTE-V Mode 4. In particular, the paper presents analytical models for the average packet delivery ratio (PDR) as a function of the distance between transmitter and receiver, and for the four different types of transmission errors that can be encountered in C-V2X Mode 4. The models are validated for a wide range of transmission parameters and traffic densities. To this aim, this study compares the results obtained with the analytical models to those obtained with a C-V2X Mode 4 simulator implemented over Veins. [ABSTRACT FROM AUTHOR]

A systematic analytical investigation of the charge distribution and gate control of the normally-off GaN double-channel MOS-HEMT (DC-MOS-HEMT) is presented in this paper. Compared to conventional GaN MOS-HEMT, the DC-MOS-HEMT features a thin AlN insertion layer (AlN-ISL) below the original two dimensional electron gas (2DEG) channel, thus forming a second channel at the interface between AlN-ISL and the underlying GaN. This paper reveals the impact of the AlN-ISL on the 2DEG distribution and the gate control of the channels. The sensitivity of ${V}_{\text {th}}$ against the recess depth is also analytically studied and is found to be nearly independent of the recess depth as long as the recess is terminated in the upper channel layer. The analytical results are well supported by numerical device simulations, and the physical mechanisms behind these findings are explained along with the analytical investigations. [ABSTRACT FROM AUTHOR]

Coupling losses induced in cable-in-conduit conductors (CICC) when subject to a time-varying magnetic field are a major issue commonly encountered in large fusion tokamaks (e.g., JT-60SA, ITER, DEMO). The knowledge of these losses is crucial to determine the stability of CICC but is yet difficult to achieve analytically (thus in a short computation time) given the specific and complex architecture of these conductors although numerical solutions such as THELMA and JACKPOT already exist. In an attempt to ease the resolution of this problem, we have previously presented a theoretical generic study of a group of elements twisted together (representing a cabling stage of a CICC) and derived the analytical expression of its coupling losses. We have now extended this study to a two cabling stage conductor by establishing an analytical model to calculate its coupling losses as function of its effective features. In a second part, we compare our results to these of THELMA and JACKPOT on geometries representing ITER CS and JT-60SA TF conductors. Finally, we have set up a specific algorithm to reconstruct strand trajectories from X-ray images and have extracted the effective geometrical parameters of a JT-60SA TF conductor. Our next objective is then to extract its effective electrical parameters from interstrand resistivity measurements to be able to compare the coupling losses predicted by our analytical model with those measured within the SULTAN facility. [ABSTRACT FROM AUTHOR]

A time-harmonic analytical model is presented for a combined study of demagnetization and rotor eccentricity in single-stator double-rotor axial flux permanent magnet synchronous machines (AFPMSM). Demagnetization defects are modeled by scaling the magnetization “square wave” by magnetization factors for each individual magnet on both rotors. Static, dynamic, and mixed rotor eccentricities are modeled using a permeance function. The original contribution of the model is that asymmetrical defects in the two air gaps of the machine can be described with acceptable accuracy and limited additional calculation time. The model is validated with a finite element method and experiments in both healthy and defected operations. Because the model has a short computation time, it is useful for real-time condition monitoring of any AFPMSM with double air gap and either concentrated or distributed windings. [ABSTRACT FROM PUBLISHER]

Cable-in-conduit conductors (CICCs) are composed of a large number of strands (superconducting composites and copper strands) twisted together in several stages with different twist pitches. They are widely used in large fusion tokamaks such as JT-60SA or ITER. However, because of their complex transposed geometry at a strand scale, the knowledge of ac coupling losses in these conductors is limited and still has some improvement margins to capture its complexity while the prediction of their behavior under transient regimes (e.g., central solenoid) is of first importance to assess a safe operation in tokamaks. Consequently, we have carried out an in-depth theoretical generic study of a single stage of a CICC and analytically derived the expression of coupling losses using physical parameters (time constant and partial shielding coefficient) determined from electromagnetic and geometrical properties. Our approach has been inspired by the MPAS model (extensively used on the experimental ITER database) but starts from the analytical description of a single stage and aims at reaching the CICC scale in an iterative way. [ABSTRACT FROM AUTHOR]

A computationally efficient method is presented to investigate additional cogging torque harmonics resulting from misalignment of the rotor and stator caused by assembly and manufacturing tolerances in an axial flux fractional pitch permanent magnet synchronous machine (PMSM). The superposition method creates a complete cogging torque profile by using a library of pole transitions over a single stator slot. The method extends previously published work, and is used to predict the effect of eccentricity misalignment in combination with pole and slot placement inaccuracies on cogging torque. Experimental data are presented supporting the superposition data indicating that static and dynamic eccentricity produce first- and second-order sidebands about the rotor and stator affected harmonics, respectively. There is good agreement between the hybrid superposition method, FEA, and measured experimental data. [ABSTRACT FROM PUBLISHER]

An analytical technique is presented to predict the magnetic field distribution in the brushless permanent magnet machine with rotor axis deflection. Focusing on the no-load field due to the magnets, a perturbation method is employed to solve the governing equations and associated boundary conditions defined on the cross section along the flux paths. The derived results consisting of the zeroth-order and the first-order terms are validated by the finite-element analysis. According to the case study, the curves from the two calculations are consistent with each other. It also shows that the rotor axis deflection results in some distortion of the air-gap flux density waveform. [ABSTRACT FROM AUTHOR]

Bragg peak range uncertainties are a persistent constraint in proton therapy. Pulsed proton beams generate protoacoustic emissions proportional to absorbed proton energy, thereby encoding dosimetry information in a detectable acoustic wave. Here, we seek to derive and model 3D protoacoustic imaging with an ultrasound array and examine the frequency characteristics of protoacoustic emissions. A formalism is presented through which protoacoustic signals can be characterized considering transducer bandwidth as well as pulse duration of the incident beam. We have also collected an experimental proton beam intensity signal from a Mevion S250 clinical machine to analyze our formalism. We also show that proton-acoustic image reconstruction is possible even when the noise amplitude is larger than the signal amplitude on individual transducers. We find that a 4 μ s Gaussian proton pulse can generate a signal in the range of MHz as long as the spatial heating function has sufficiently high temperature gradients., Competing Interests: VI.Conflicts of Interest Statement All authors declare that they have no known conflicts of interest in terms of competing financial interests or personal relationships that could have an influence or are relevant to the work reported in this paper.

In this paper, analytical, numerical-, and measurement-based methods for extracting the resistance, inductance, capacitance, and conductance of through silicon vias (TSVs) are classified, quantified, and compared from 100 MHz to 100 GHz. An in-depth analysis of the assumptions behind these methods is made, from which their limits of accuracy/validity are defined. Based on this, the most reliable methods within the studied frequency range are proposed. The TSVs are designed, fabricated, and measured. Very good correlation is obtained between electrical parameters of the TSVs extracted from the measurements and electromagnetic field simulations. [ABSTRACT FROM PUBLISHER]

This paper proposes a permanent magnet machine having mixed high-cost NdFeB and low-cost ferrite magnets with modular unequal magnet height poles, i.e., the modular Hat- and T-type magnet poles, together with optimized Halbach magnetization. The investigation shows that the modular T-type magnet poles with mixed magnet grade and unequal side-magnet height exhibit significant potential to achieve low torque ripple, relatively large electromagnetic torque, and high magnet usage efficiency simultaneously. [ABSTRACT FROM AUTHOR]

This paper presents the design, fabrication, packaging, and experimental characterization of the first temperature-sensitive MEMS capacitors for health monitoring applications up to 275 ^\circ\C. The capacitive sensor chip is 2 \times 2\ \mm^2 fabricated on a 500-\mu\m-thick Si wafer and comprises an array of 220 individual 10 \times 250 \ \mu\m^2 inherently robust bimorphs. This first part focuses on the fabrication and packaging, thermomechanical design, electromagnetic modeling, and technology of the unpackaged and packaged bimorph beams. On the thermomechanical part, the measured profiles match theoretically predicted profiles from 20 ^\circ\C to 250 ^ \circ\C within 4% and 3% at the beam midpoints and tips, respectively. Similarly, experimentally obtained capacitance changes for five separate packaged devices show a mean error of less than 3% and a maximum error of less than 5% from the theoretical model up to 165 ^\circ \C. The packaged sensors simultaneously achieve for the first time: 1) high temperature operation; 2) monotonic capacitance–temperature response from 20 ^\circ \C to 300 ^\circ\C; 3) hermetic sealing; 4) miniature size of 5.4 \times 5.4 \times 3.6\ \mm^3; and 5) capacitance quality factor of over 5000 at 20 ^\circ \C and 1000 at 160 ^\circ\C. Experimental results underline the tradeoffs between beam arrangement, attachment method to the package, and package to the quality factor of the device.\hfill[2011-0316] [ABSTRACT FROM AUTHOR]

Since the torque ripple reduction by adopting magnet-shaping methods is often associated with a negative impact on electromagnetic torque as well as increased cost, this paper proposes magnet poles having unequal magnet height, i.e., the Hat- and T-type magnets, together with optimized Halbach magnetization. An analytical model based on subdomain technique is employed for investigation, while its validity is examined by finite-element analysis. It shows that comparing to conventional three-segment Halbach array, Hat-type magnet pole and traditional magnet shapings, T-type magnet pole exhibits significant potential to achieve low torque ripple, high electromagnetic torque, and low magnet usage simultaneously. [ABSTRACT FROM AUTHOR]

An analytical subdomain model for the prediction of open-circuit magnetic field in slotted surface-mounted permanent-magnet machines is developed in this paper, which considers the effect of rotor eccentricity. The magnetic field domain is divided into three types of simple and regular subdomains, viz. magnet, air gap, and stator slots. The analytical solution is derived by solving the field governing equations in each subdomain and applying the boundary conditions to the interfaces between these subdomains. The perturbation method is used to describe the effect of rotor eccentricity. The model accurately accounts for the effect of stator slots, the mutual influence between slots, and rotor eccentricity. The analytical model is validated by the corresponding finite-element results. The results show that the proposed subdomain model up to the first-order perturbation can accurately predict the open-circuit magnetic field in slotted surface-mounted permanent-magnet machines with rotor eccentricity. [ABSTRACT FROM AUTHOR]

This paper introduces an original approach for characterizing and modeling the external induction variation of a complex ferromagnetic structure undergoing magneto-mechanical effects. From the Jiles Law of Approach that describes the intrinsic magnetization changes due to magnetostriction, an expression of the law in terms of conveniently external measurable induction B is derived for thin ferromagnetic devices. Based on measurements of induction performed by external sensors on an internally pressurized cylinder, an analytical model is found. This model is then tested for any orientation of the magnetic field with respect to stress, from parallel to orthogonal . [ABSTRACT FROM PUBLISHER]

A previously published analytical model for thermal stress and strain in idealized plated-through-vias (PTVs) has been adapted to conduct elastic-plastic analyses of vias with geometric defects using elastic stress concentration factors calculated earlier. The von Mises stress amplitude, at the mid-plane of the perfect via and at the defect (\Delta\sigma0 and \Delta\sigma, respectively), and the cumulative plastic von Mises strain, also at the mid-plane of a perfect via and at a defect (\varepsilon0^{pl} and \varepsilon^pl, respectively), compared well with results of finite element analyses (FEAs). Four types of PTV defects were evaluated: barrel thickness reduction, occasional waviness, continuous waviness, and wicking. This model provides a relatively simple alternative to FEA to calculate stresses and strains in vias with defects as well as in perfect vias subjected to multiple thermal cycles. This model provides a tool to investigate quickly the influence of possible PTV design dimensions and defects under thermal cycling conditions (i.e., which are particularly damaging in a given situation). It is much easier than FEA for parametric studies like this. It also provides a means for calculating damage metrics, such as the cumulative von Mises strain, which can then be empirically correlated with the cycles to failure data from thermal cycling tests of PTVs. [ABSTRACT FROM PUBLISHER]

The application of integral equations for the frequency domain analysis of scattering problems requires the accurate evaluation of interaction integrals. Generally speaking, the most critical integral is the selfpatch. However, due to the non-smoothness of the Green function, this integral is also the toughest to calculate numerically. In previous work, the source and test integrals have been determined analytically for the 1/R singularity, i.e., the static kernel. In this work we extend this result to the terms of the form Rn, ∀n ε {0, 1, 2, 3, 4} that occur in the Taylor expansion of the Green function. Numerical testing shows that truncating the Taylor series beyond n= 4 yields a highly accurate result for λ/7 and λ/10 discretizations. These analytical formulas are also very robust when applied to highly irregular triangles. [ABSTRACT FROM AUTHOR]

The cutoff wavelengths λcmn of elliptical metallic waveguides with perfectly conducting walls are determined analytically. Two different methods are used for the evaluation. In the first, the electromagnetic field is expressed in terms of elliptical-cylindrical wave functions. In the second, a shape perturbation method, the field is expressed in terms of circular-cylindrical wave functions only, while the equation of the elliptical boundary is given in polar coordinates. Analytical expressions are obtained for the cutoff wavelengths, when the solution is specialized to small values of the eccentricity h = c/2a, (h ⪡ 1), with c the interfocal distance of the elliptical waveguide and 2a the length of its major axis. In this case, exact closed-form algebraic expressions, free of Mathieu as well as of Bessel functions, are obtained for the expansion coefficients gmn(2) and gmn(4) in the resulting relation λcmn(h) = λcmn(0) [1 + gmn(2)h² + gmn(4)h4 + O (h6)] for the cutoff wavelengths. These expressions are valid for each m and n, namely, for the general mode. Numerical results for all types of modes and comparison with existing ones are also included. [ABSTRACT FROM AUTHOR]

This paper presents three-dimensional expressions for the optimization of permanent-magnet couplings. First, we give a fully analytical expression of the azimuthal field created by one arc-shaped permanent magnet radially polarized which takes into account its magnetic pole volume density. Such an expression has a very low computational cost and is exact for all points in space. Then, we propose two semianalytical expressions of the azimuthal force and the torque exerted between two arc-shaped permanent magnets. These expressions are valid for thick or thin arc-shaped permanent magnets. Furthermore, this approach allows us to realize easily parametric studies and optimizations. The analytical approach taken in this paper, based on the Coulombian model, is a good alternative compared to the finite element method generally used to study such configurations. [ABSTRACT FROM PUBLISHER]

We present analytical and numerical methods for determining the magnetic field distribution in a tubular permanent-magnet actuator (TPMA). In Part I, we present the semianalytical method. This method has the advantage of a relatively short computation time and it gives physical insight. We make an extension for skewed topologies, which offer the benefit of reducing the large force ripples of the TPMA. However, a lot of assumptions and simplifications with respect to the slotted structure have to be made in order to come to a relatively simple semianalytical description. To model the slotting effect and the related cogging force, we apply a Schwarz-Christoffel (SC) mapping for magnetic field and force calculations in Part II of the paper. Validation of the models is done with finite-element analysis. [ABSTRACT FROM AUTHOR]

A fully analytical steady state solution is presented for the problem of 3-D conjugate heat transfer in flip chip electronic packages with multiple general areal power sources, cooled by heatsinks using forced convection. The inherent simplicity of the proposed approach allows for expedient yet detailed package cooling/thermal analysis and evaluation of what-if scenarios while requiring only modest computational resources such as a personal computer. The soundness of the approach presented is demonstrated via excellent correlation with the results of experimental tests on flip-chip thermal test packages in a wind tunnel. The techniques developed herein are fairly general and can be readily adapted to other package designs wherein the primary heat transfer path is through the die, die-lid interface, lid, lid-sink interface and heatsink to the airflow through the fins. [ABSTRACT FROM AUTHOR]

This paper presents an analytical model of axial air gap induction motors with solid rotors that includes the two-dimensional current distribution in the rotor. The model is quasi-three-dimensional and considers the circumferential as well as radial and angular dimensions. Also, one can consider the various arrangements of the stator windings i.e., single layer, double layer, and gramme for this type of motor. The method is valid for both constant current and constant voltage sources. Comparison of the simulation results of the produced torque with the experimental ones shows the high accuracy of the proposed method. [ABSTRACT FROM AUTHOR]