Criteria for Identifying the Major Risks Associated with Tailings Ponds in Romania

Damage caused by accidents at hydraulic structures, due to natural hazards or human causes (e.g. terrorist sabotage) can be comparable to those caused by natural disasters. The paper identifies the major advantages of a common methodology for risk identification and quantification regarding the potential impact of accidents at tailings dams on the environment. Relevant Romanian and EU legislation and regulations enacted following the “Baia Mare” accident in 2000 are reviewed, along with a common risk evaluation methodology that can be applied by the mining sector to tailings dams.     

Acoustic behavior design with simulated annealing

The present work extends the matrix method formalism, by using a supplementary computational method based on a simulated annealing algorithm, with the aim to design acoustical structures, especially acoustic filters. The algorithm introduces a cost function, which is minimized by the simulated annealing algorithm. Also, some numerical computations have been carried out to design some special acoustic filters and an experimental analysis of the designed acoustic filters is provided to test the validity of the method.     

Energy policy and European utilities’ strategy: Lessons from the liberalisation and privatisation of the energy sector in Romania

In the context of energy sector reforms pursued by Romanian government since 1990s, we compare and contrast the market outcomes of European utilities’ investment with the host government policy objectives. We begin with energy market reform in Romania and review governments’ efforts to attract foreign direct investment (FDI) and to gradually withdraw from the distribution and supply segments of electricity market. Subsequently, we illustrate the scope European utilities have had, market policy and design notwithstanding, for consolidating market power through regional dominance. We examine the extent to which these utilities have sought to enhance their positions through horizontal and vertical integration, counter to the EU plans for a competitive market structure. We find that the investments of European incumbents have not been resoundingly successful: although market entrance may have been justified on long-term strategic grounds, in the immediate term, segments acquired through competitive auctions have yielded modest regulated returns. Finally, we discuss the extent to which policy makers have achieved their goals. Although the short-term benefits of a competitive market structure have reached some consumers, a renewed interest in promoting ‘national champions’ reflect frustration with market mechanisms as a means of ensuring long-term strategic investments in the sector.     

Untersuchung des Verhaltens von Stählen unter wiederholter Schlagzugbeanspruchung

Versuchseinrichtung zur Durchführung von Schlagzugversuchen mit Ermittlung der verbrauchten Schlagarbeit. Schlagzugversuche an Rundproben mit 6, 7 und 8 mm Dmr. aus Stahl St 50. Anwendung von Schlagenergien zwischen 300 und 30 J. Ertragbare Anzahl der Schläge in Abhängigkeit von der spezifischen Schlagarbeit. Einfluß des Probendurchmessers auf die spezifische Dauerschlagarbeit. Bleibende Dehnung bei wiederholter Schlagzugbeanspruchung im Zusammenhang mit der Anzahl der Schläge, der Energie der Einzelschläge und der verbrauchten Gesamtenergie bis zum Bruch. Schlagwiderstand des Werkstoffes.     

An efficient approximate profiling method for the rack gear tool

This paper presents a simplified algorithm for the profiling of the rack gear tool to generate the active profile associated with rolling centrodes. The algorithm is based on the enveloping surfaces principles and reduces the computational problem by proposing an approximate representation of tool’s profile using only three or four points on the profile to be generated by using Bezier representations of the surfaces. The algorithm computes the coefficients of a Bezier substitution polynomial instead of computing hundreds of points on the active profile. This simplifies the solution methodology and requires only a limited number of points along the profile to be generated. The algorithm is computationally efficient and can also be used in the case when the active profile to be generated is physically measured at a few points. Examples include mill tools, splined shafts, and gears.     

Considerations on CDMA–OFDM System Performances in Different Channel Environments for Different Modulation and Coding Scenarios

This paper presents a number of results obtained based on a CDMA–OFDM simulator developed in Matlab. The simulator has been extended to accommodate in a flexible manner to different modulation schemes, multiple access techniques, spreading codes types and lengths, convolutional codes rates, number of users and types of channels. The performances are evaluated and compared based on the Bit Error Rate (BER) as a function of the Signal to Noise Ratio (SNR) results achieved in different scenarios. In this paper are presented the results obtained by the developed simulator for two types of spreading codes—perfectly orthogonal Walsh type codes versus pseudo-orthogonal Gold type codes. The performances are evaluated in different channel environments the classical AWGN, pedestrian, vehicular and indoor ITU-R M.1225 models, for BPSK and QPSK modulations and 1/2 respectively 3/4 rate channel coding. Furthermore, since the results shown that the Gold spreading codes, QPSK modulation and 1/2 rate coding achieves the best performances in all type of channels analyzed, the authors investigate the effect of the code length and of the number of users on these results.