Municipality Size and Efficiency of Local Public Services: Does Size Matter?

Similarly to western Germany in the 1960s and 1970s, the eastern part of Germany has experienced a still ongoing process of numerous amalgamations among counties, towns and municipalities since the mid-1990s. The evidence in the economic literature is mixed with regard to the claimed expenditure reductions and efficiency gains from municipal mergers. We therefore analyze the global efficiency of the municipalities in Saxony-Anhalt, for the first time in this context, using a double-bootstrap procedure combining DEA and truncated regression. This allows including environmental variables to control for exogenous determinants of municipal efficiency. Our focus thereby is on institutional and fiscal variables. Moreover, the scale efficiency is estimated to find out whether large units are necessary to benefit from scale economies. In contrast to previous studies, we chose the aggregate budget of municipal associations (“Verwaltungsgemeinschaften”) as the object of our analysis since important competences of the member municipalities are settled on a joint administrative level. Furthermore, we use a data set that has been carefully adjusted for bookkeeping items and transfers within the communal level. On the “eve” of a mayor municipal reform the majority of the municipalities were found to have an approximately scale-efficient size and centralized organizational forms (“Einheitsgemeinden”) showed no efficiency advantage over municipal associations.efficiency, local government, DEA, bootstrap, demographic change, local institutions

Größe ist nicht alles – Die Effizienz der kommunalen Leistungserstellung am Beispiel Sachsen-Anhalts

The proponents of municipal area reforms – e.g. the recently completed reform in Saxony-Anhalt – expect that municipal amalgamations or centralized organizational forms save costs or increase the efficiency of local public service provision. This article examines the potential efficiency deficits of Saxony-Anhalt´s fragmented municipal structures on the eve of the crucial phase of the municipal reform. The results of a two-step DEA bootstrap procedure show that decentralized municipalities (“Verwaltungsgemeinschaften”) do not have to be significantly less efficient than centralized municipalities (“Einheitsgemeinden”). Furthermore, the results of the scale efficiency analysis suggest that the majority of Saxony-Anhalt´s communities already had an approximately efficient “firm size” – if the aggregated level of the municipal associations is examined. The relationship between scale efficiency and population is U-shaped. On the one hand, the results do not support the preservation of micro-municipalities or the formation of municipal associations with more than ten members. On the other hand, the results provide also no evidence for the necessity to reduce the number of towns and municipalities in Saxony-Anhalt from 1118 in 2004 to currently 219 – even if the looming population decline is taken into account.municipal finance, municipal tasks, local institutions, productivity, efficiency analysis, DEA, bootstrap, demographic change

Validation of a New Fast-Time Scale Code for Advanced Simulations of Gyrotron Cavities

Gyrotrons for fusion applications are microwave vacuum tubes that are capable to produce an output power in the megawatt range at long pulses up to continuous wave (CW) and at frequencies above 100 GHz. That is possible due to the working principle of gyrotrons which allows using cavities with a very large electrical size (in the order of several cm) compared to the operating wavelength (in the order of a few mm). This mandatory requirement for high output power is a challenge in simulating the interaction between the electromagnetic (EM) field and the electron beam in a gyrotron resonator. Due to this, the simulation of the electron interaction in gyrotrons are typically carried out by using computer codes which make use of the very specific properties of the EM problem to simplify the calculations. At KIT, a new code names “SimpleRick” is under development. A fast-time scale Particle-in-Cell (PIC) method is implemented to complement the classical models used for gyrotron simulation. The PIC code introduces significantly fewer assumptions than the classical model and may therefore represent more physical details. For example, in contrast to the classical models, the new model can represent non-symmetric electron beams. In this work, the numerical implementation and the performance of this PIC model are verified and a new method for the calculation of the eigenvalues of coaxial gyrotron resonators is shown in more detail

Time-Domain Simulation of Helical Gyro-TWTs With Coupled Modes Method and 3-D Particle Beam

A new self-consistent time-domain model for the simulation of gyrotron traveling-wave tubes with a helically corrugated interaction space (helical gyro-TWTs) is presented. The new model links classical methods using the approach of slowly varying variables together with an expansion of the electromagnetic field in eigenmodes and advanced full-wave particle-in-cell (PIC) solvers. The aim is to significantly reduce the required calculation time compared to full-wave PIC solvers, while less strict assumptions are introduced as in the classical approaches of slowly varying variables. For the first time, the classical theory of coupled circular waveguide modes for the description of the operating electromagnetic eigenmode in the helical interaction space is combined with a 3-D PIC representation of the electron beam. This allows the simulation of the beam–wave interaction over a broad bandwidth and at arbitrary harmonics of the cyclotron frequency. In addition, arbitrary electron beams (with spreads, offsets of the guiding center from the symmetry axis, and so on) can be investigated. The new approach is compared with the full-wave 3-D PIC code CST Microwave Studio. A good agreement of the simulation results is achieved, while the computing time is significantly reduced

Simple Feedback System for Passive Mode Locked Gyro-Devices at 263 GHz

A promising new source to generate a periodic series of coherent, ultra-short pulses in the millimeter and submillimeter frequency range is based on the method of passive mode locking [1]. The basic principle is well known from laser physics [2]. A realization for millimeter and sub-millimeter waves consists of an amplifier and a saturable absorber coupled in a feedback loop. In this paper, a coupling system for two single-window vacuum electron tubes in a mode-locked microwave oscillator is presented. Based on full-wave simulations, the key components of the proposed feedback system at 263 GHz (typical DNP-NMR frequency) are designed

Gyrotron multistage depressed collector based on E × B drift concept using azimuthal electric field. II: Upgraded designs

Multistage Depressed Collectors (MDCs) are nontrivial for high-frequency gyrotrons. A basic conceptual design of an E x B MDC using azimuthal electric fields was proposed in Part I of this series. In the present work, several upgraded design proposals based on the basic one will be elaborated. These proposals will significantly reduce the back-stream of electrons, which was the main drawback of the basic design proposal. Another upgraded design proposal will shrink the length and maximal radius of the MDC to be only a fraction of its full-length version. A conceptual design of the final MDC proposal will be given at the end

Multifaceted Simulations Reproducing Experimental Results from the 1.5-MW 140-GHz Preprototype Gyrotron for W7-X

A multifaceted simulation procedure, addressing the electron beam properties, the beam-wave interaction, and the internal losses, has been used for the simulation of the experimental operation of a 1.5-MW 140-GHz short-pulse preprototype gyrotron. The preprototype is related to the development of 1.5-MW gyrotrons for the upgrade of the electron cyclotron resonance heating system at the stellarator W7-X. A very good reproduction of experimental results has been achieved by simulation, without resorting to arbitrary speculations. This validated the numerical tools as well as the design and fabrication of the short-pulse preprototype, which fully reached the target of efficient 1.5-MW operation in millisecond pulses. Special attention has been given to simulating the possibility of parasitic after-cavity interaction in the gyrotron launcher. Also, parasitic backward-wave excitation in the gyrotron cavity has been demonstrated by simulation, at a frequency and voltage range in agreement with experimentally observed parasitic oscillations. This offers an additional possibility with respect to the origin of deleterious parasitic oscillations in high-power gyrotrons, which are usually attributed mainly to the gyrotron beam tunnel

Investigation of a Mini-Channel Cavity Cooling Concept for a 170 GHz, 2 MW Coaxial-Cavity Gyrotron

The maximum heat load on the cavity wall of high power fusion gyrotrons is one of the major limiting technological factors for the operation of the tube. To achieve the requested output power, efficiency and pulse length, a very efficient cooling of the interaction structure is mandatory. In this work, the performance of a mini-channel cavity cooling system for a 170 GHz, 2 MW coaxial-cavity gyrotron is numerically investigated, including the development of a mock-up test set-up for experimental validation