Results 1 - 10 of 2071
Results 1 - 10 of 2071. Search took: 0.032 seconds
|Sort by: date | relevance|
[en] This paper selects stochastic volatility (SV) as the uncertainty or volatility measure to re-examine the Samuelson hypothesis of maturity effect (SHME) (Samuelson, 1965). Stochastic dominance is used to examine whether the stochastic volatility level dominates with respect to maturity. The empirical analyses of energy-futures price series generally provide mild support for this hypothesis in terms of the first two degrees of stochastic dominance. Each type of futures has its own properties with respect to the maturity effect. SV levels play a role in determining the testing outcome. The hypothesis is more likely to hold at low SV levels. The higher the volatility level, the less likely the SHME will hold because SV surges to its peak level regardless of maturity. - Highlights: • This paper selects stochastic volatility (SV) as the uncertainty or volatility measure to re-examine the Samuelson hypothesis. • Stochastic dominance is employed to examine if the SV level dominates with respect to maturity. • Energy futures price series give mild support to this hypothesis in terms of the first two orders of stochastic dominance. • The hypothesis is more likely to hold at low SV levels. • The higher the volatility level, the less likely the hypothesis will hold because SV surges to its peak level regardless of maturity.
[en] In general, the developing countries due to changes in supply and demand for energy in the world, are facing several problems, such as: 1. Energy growth. 2.Energy consumption 3.Environmental protection. The objective of this paper is to study the problems caused by the increase in the energy consumption of the developing countries. also several guideline and solution schemes are recommended for these problems
[en] This presentation dealt with methods for assessing commodity price risk in an asset transaction; the setting of risk management objectives; building hedging into the financing; and internal reporting and accounting to mitigate trading risks. It also provided some recent examples of successful hedging in gas asset transactions. The objectives of risk management and the nature of hedging and speculation were explored. An approach to price risk management was proposed. The development of price risk management tools, and techniques for managing risks involving interest rates, foreign exchange, and commodities were examined. figs
[en] This paper develops economic definitions of energy quality for individual fuels and energy aggregates. There are use- and exchange-value concepts, as well as marginal and total measures, of energy quality. A factor augmentation or quality coefficients approach corresponds to the use-value definition while indicators based on distance functions and relative prices are exchange-value based definitions. These indicators are identical when the elasticity of substitution between fuels is infinity but diverge or cannot be computed for other interfuel elasticities of substitution. When the elasticity of substitution is zero only the quality coefficients approach is defined. I also show that 1) the ratio of an energy volume index to aggregate joules cannot be considered a complete indicator of aggregate energy quality as it does not account for quality changes in the component fuels 2) demand curve integrals do not provide information on relative use-values or fuel qualities when the elasticity of substitution is unity or less. (author)
[en] In the study, 6082 Al and 7075 Al samples were subjected to a solution taking place at 580 °C for 1 min using ultrahigh frequency induction heating system (UHFIHS) and water was supplied at the end of the process. Artificially aging was then carried out at 190 °C for 2, 4, 6 and 8 min. In both applications, heating was carried out using an induction system with a frequency of 900 kHz and a power of 2.8 kW. For these aluminum series and shapes, induction heating and heat treatment costs in different shapes are calculated. In addition, the hardness values obtained from artificially aged 6082 Al and 7075 Al samples at 190 °C for 10 h were compared with conventional methods after 5 h at 540 °C for 5 h. As a result, the hardness values of 6082 Al samples, which were obtained in 10 h by conventional methods, were obtained by artificial aging for only 8 min using induction system.
[es]Muestras de las aleaciones 6082 A1 y 7075 A1 se sometieron a un tratamiento térmico en horno de inducción de ultraalta frecuencia (UHFIHS) a 580 ºC durante 1 min y suministro de agua al final del proceso. El envejecimiento artificial se llevó a cabo a 190 °C durante 2, 4, 6 y 8 min. En ambas aplicaciones, el calentamiento se llevó a cabo utilizando un sistema de inducción con una frecuencia de 900 kHz y una potencia de 2,8 kW. Para estas series y diseños de aluminio, se calcularon los costos del tratamiento térmico. Adicionalmente, se compararon los valores de dureza de las muestras de 6082 A1 y 7075 A1 envejecidas artificialmente a 190 °C durante 10 h con los métodos convencionales 540 °C durante 5 h. Los resultados de dureza de la muestra 6082 Al obtenidos en 10 h mediante métodos convencionales, tardaron sólo 8 min mediante el envejecimiento artificial con el sistema de inducción.
[en] This paper presents modeling of unified power quality conditioner (UPQC) in load flow calculations for steady-state voltage compensation. An accurate model for this device is derived to use in load flow calculations. The rating of this device as well as direction of reactive power injection required to compensate voltage to the desired value (1 p.u.) is derived and discussed analytically and mathematically using phasor diagram method. Since performance of the compensator varies when it reaches to its maximum capacity, modeling of UPQC in its maximum rating of reactive power injection is derived. The validity of the proposed model is examined using two standard distribution systems consisting of 33 and 69 nodes, respectively. The best location of UPQC for under voltage problem mitigation in the distribution network is determined. The results show the validity of the proposed model for UPQC in large distribution systems.
[en] Energy risk management is the principal topic of this paper. Four major subjects are examined: cross-commodity trading objectives (reduce the risk of an underlying exposure in another commodity); portfolio risk reduction (an Alberta power distributor exposed to high pool prices could protect against high pool prices through a fixed price purchase of Alberta natural gas); tailoring pricing to customer needs (sell power to the gas producer indexed to the price of gas); and (4) reducing insurance costs (rather than purchasing downside protection (puts) individually against oil and gas prices, a producer could purchase a basket option). Since the key issue in cross-commodity transactions is the estimation of correlation, it is important to be prepared to alter correlation assumptions. 1 tab., 2 figs
[en] This presentation will be based on the World Energy Council's recently published report, Energy Market Reform: Lessons Learned and Next Steps with Special Emphasis on the Energy Access Problems of Developing Countries. The report draws on practical lessons from past studies carried out by the World Energy Council and on current experiences on the desirable architecture of market reforms in electricity and natural gas. The approach of the study was not to further deepen the analysis or to provide technical recommendations but rather, to build a debate guided by the common thread of energy security and end-user empowerment, highlighting the possible areas of conflict of interest and the broad solutions that might be chosen depending on the local circumstances for different parts of the energy chains. The ambition was to identify key concerns and to initiate a debate on possible answers.(author)