This paper presents the lumped parameters model of an internal gear crescent pump with relief valve, able to estimate the steady-state flow-pressure characteristic and the pressure ripple. The approach is based on the identification of three variable control volumes regardless of the number of gear teeth. The model has been implemented in the commercial environment LMS Amesim with the developme...

The prediction of RF properties of complex accelerating structures is an important issue in computational accelerator physics. This paper describes the derivation of state space equations for complex structures based on real eigenmodes of sections of the decomposed complex structure. The state space equations enable the calculation of system responses due to port excitations by means of standar...

We analyse the fi nancial performance of small German hospitals based on balance sheet data of about 1,000 hospitals in 2007. Measures of fi nancial performance are the earnings before interest, tax, depreciation, and amortisation (EBITDA) and the probability of default (PD). We fi nd that, on average, small hospitals have more fi nancial diffi culties than large ones. However, there is conside...

* We are grateful to the many members of the MIT and Harvard economics communities who have generously provided us with insightful conversations, comments on an earlier draft of this paper and practical support. We are particularly indebted to

We analyze the investment decision of a firm that has an option to complete an investment project either in one lump or in two smaller parts at distinct points in time. The firm faces a trade-off between the cost savings that arise when the project is completed at once and the additional flexibility that arises when the firm is able to respond to resolving uncertainty by choosing optimal timing...

A passive 2nd-order sigma-delta modulator based on a cascade of first-order lowpass filters was designed, fabricated, and tested. A lumped RC filter is added in the loop of a conventional 1st-order passive sigma-delta modulator in order to improve the linearity of its transfer function. A low power edge-triggered comparator was designed and fabricated along with lumped components in ON Semicond...

This paper is focused on the creation of an efficient electromagnetic model of MEMS switches which operates at microwave frequencies. The switches are first characterized using a full wave analysis based on a finite element method to extract the S-parameters of the switches for different geometrical dimensions. From the S-parameter database, a scalable lumped circuit model is extracted to allow...

0 1 5 Frequency [GHz] 6 2 3 4 Abstract The validity of lumped element microwave class-F amplifier circuit design has been demonstrated experimentally. By means of the proposed class-F amplifier design method, more than 4th-order higher harmonic frequencies can be taken into account in class-F microwave amplifier design using only lumped element components. In this approach, miniaturization of c...

⎯An analysis of a 3 dB lumped-element directional coupler (LEDC) based on arbitrary terminal impedance is described numerically. To solve the conflicted requirement for broad bandwidth and small size in LEDC, a new structure of coupler is introduced, which can significantly improve bandwidth and whose size is only 3 cm×4 cm on the conditions of the frequency domain of 410 MHz to 490 MHz. The me...