Results 1 - 10 of 1610
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[en] A source of white-light radiation that generates few-cycle pulses with controlled peak power values has been developed. These ultrafast pulses have been observed by spectral broadening of 32 fs pulses through nonlinear self-phase modulation in a neon-filled hollow-fiber then compressed with a pair of chirped mirrors for dispersion compensation. The observed pulses reached transform-limited duration of 5.77 fs and their peak power values varied from 57 GW up to 104 GW at repetition rate of 1 kHz. Moreover, the applied method is used for a direct tuning of the peak power of the output pulses through varying the chirping of the input pulses at different neon pressures. The observed results may give an opportunity to control the ultrafast interaction dynamics on the femtosecond time scale and facilitate the regeneration of attosecond pulses. - Highlights: • A source of ultrafast white-light radiation has been developed. • Observation of transform-limited pulses of 5.77 fs by compressing 32 fs pulses. • Attainment of tunable peak power values varied from 57 GW up to 104 GW.
[en] This paper discusses experiments conducted on the Athens Utilities Board and simulations that were performed to evaluate the capacity utilization benefits of distribution automation. The primary benefits of loss and peak load reductions are not realized on the AUB system. The characteristics of the AUB system which preclude achieving these benefits are discussed
[en] We demonstrated a 100 TW-class femtosecond Ti: sapphire laser running at repetition rate of 0.1 Hz by adding a stage amplifier in the 20 TW/10 Hz laser facility (XL-II). Pumping the new stage amplifier with the 25 J green Nd:glass laser, we successfully upgraded the laser energy to 3.4 J with duration of 29 fs, corresponding to a peak power of 117 TW. (authors)
[en] Congestion cost allocation is a very important topic in congestion management. Allocation methods based on the Aumann-Shapley value use the discrete numerical integration method, which needs to solve the incremented OPF solution many times, and as such it is not suitable for practical application to large-scale systems. The optimal solution and its sensitivity change tendency during congestion removal using a DC optimal power flow (OPF) process is analysed. A simple continuous integration method based on the sensitivity is proposed for the congestion cost allocation. The proposed sensitivity analysis method needs a smaller computation time than the method based on using the quadratic method and inner point iteration. The proposed congestion cost allocation method uses a continuous integration method rather than discrete numerical integration. The method does not need to solve the incremented OPF solutions; which allows it use in large-scale systems. The method can also be used for AC OPF congestion management. (author)
[en] This paper uses support vector machines (SVM) based learning algorithm to select important variables that help explain the real-time peak electricity price in the Ontario market. The Ontario market was opened to competition only in May 2002. Due to the limited number of observations available, finding a set of variables that can explain the independent power market of Ontario (IMO) real-time peak price is a significant challenge for the traders and analysts. The kernel regressions of the explanatory variables on the IMO real-time average peak price show that non-linear dependencies exist between the explanatory variables and the IMO price. This non-linear relationship combined with the low variable-observation ratio rule out conventional statistical analysis. Hence, we use an alternative machine learning technique to find the important explanatory variables for the IMO real-time average peak price. SVM sensitivity analysis based results find that the IMO's predispatch average peak price, the actual import peak volume, the peak load of the Ontario market and the net available supply after accounting for load (energy excess) are some of the most important variables in explaining the real-time average peak price in the Ontario electricity market. (author)
[en] The technical and economic potentials for solar thermal power plants were evaluated in an extended study for the Mediterranean area. The results are representative for most of other regions within the earth's sun belt. (authors)
[en] A high power YAG/Nd:YAG/YAG ceramic planar waveguide laser was demonstrated. For continuous wave regime, a maximum output power of 10.4 W at a center wavelength of 1064.6 nm was obtained under an absorbed pump power of 17.4 W, corresponding to an optical-to-optical conversion efficiency of 59.8%. For acousto-optically Q -switched operation, we obtained 2.5 W of output power at a pulse repetition frequency of 10 kHz. The pulse duration was 6.5 ns with peak power and pulse energy of 38.5 kW and 0.25 mJ, respectively. (letter)
[en] We develop a method of executing complete population transfers between quantum states in a piecewise manner using a series of femtosecond laser pulses. The method can be applied to a large class of problems as it benefits from the high peak powers and large spectral bandwidths afforded by femtosecond pulses. The degree of population transfer is robust to a wide variation in the absolute and relative intensities, durations, and time ordering of the pulses. The method is studied in detail for atomic sodium where piecewise adiabatic population transfer, as well as the induction of Ramsey-type interferences, is demonstrated
[en] Peak demand for electricity in North America is expected to grow, challenging electrical utilities to supply this demand in a cost-effective, reliable manner. Therefore, there is growing interest in strategies to reduce peak demand by eliminating electricity use, or shifting it to non-peak times. This strategy is commonly called 'demand response'. In households, common strategies are time-varying pricing, which charge more for energy use on peak, or direct load control, which allows utilities to curtail certain loads during high demand periods. We reviewed recent North American studies of these strategies. The data suggest that the most effective strategy is a critical peak price (CPP) program with enabling technology to automatically curtail loads on event days. There is little evidence that this causes substantial hardship for occupants, particularly if they have input into which loads are controlled and how, and have an override option. In such cases, a peak load reduction of at least 30% is a reasonable expectation. It might be possible to attain such load reductions without enabling technology by focusing on household types more likely to respond, and providing them with excellent support. A simple time-of-use (TOU) program can only expect to realise on-peak reductions of 5%.
[en] We discuss criteria for designing an optimal ''green field'' proton driver for a neutrino factory. The driver parameters are determined by considerations of space charge, power capabilities of the target, beam loading and available RF peak power