نتایج جستجو برای: solar cycles

تعداد نتایج: 208344  

Journal: :Astronomical School’s Report 2015

2012
Nicola Scafetta

Numerous empirical evidences suggest that planetary tides may influence solar activity. In particular, it has been shown that: (1) the well-known 11-year Schwabe sunspot number cycle is constrained between the spring tidal period of Jupiter and Saturn, 9:93 year, and the tidal orbital period of Jupiter, 11:86 year, and a model based on these cycles can reconstruct solar dynamics at multiple tim...

2006
Bhuwan Joshi Anita Joshi

In this paper the N−S asymmetry of the soft X-ray flare index (FISXR) during the solar cycles 21, 22 and 23 has been analyzed. The results show the existence of a real N−S asymmetry which is strengthened during solar minimum. The slope of the regression lines fitted to the daily values of asymmetry time series has been found to be negative in all the three cycles. The yearly asymmetry curve can...

Journal: :Science 1984
M R Rampino R B Stothers

Time-series analysis reveals two dominant, stable long-term periodicities approximately equal to 33 +/- 3 and 260 +/- 25 million years in the known series of geological and biological upheavals during the Phanerozoic Eon. Because the cycles of these episodes agree in period and phase with the cycles of impact cratering on Earth, these results suggest that periodic comet impacts strongly influen...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی - دانشکده مهندسی برق و کامپیوتر 1391

many mobile and off-grid devices include electronics and other electrical consumers like servo drives, which need a quite low supply power. since the price for photovoltaic modules drops continuously, photovoltaic power supply is interesting in more and more applications. in solar powered systems, a battery is needed to store energy for the night and cloudy periods. the power electronics of suc...

In this paper thermodynamic modeling and comprehensive performance analysis of a real integrated solar combined cycle (ISCC) power plant are performed. Performance of the plant cycle is assessed in off-design condition and in two operation modes of power-boosting and fuel-saving. Such an approach has not been considered for an ISCC plant in the previous studies. Under studied ISCC which is loca...

2012
Cristina Menni Walter E. Lowell Joan Bentzen Roberto Bergamaschi Filippo Martinelli Boneschi Vittorio Martinelli Luisa Bernardinelli Egon Stenager George E. Davis Luisa Foco

We examined the role of ultraviolet radiation (UVR) in persons diagnosed with multiple sclerosis (MS) in four different populations, Italians, Danish, White and African Americans. We tested whether variation in UVR as determined by seasons (short term variation) and solar cycles (long term variation) is related to MS birth month and to survival as measured by lifespan. Cases were selected from ...

2016
Claudia Toro

This paper presents an analysis of solar-heat driven Brayton, Rankine and Stirling cycles operating in space with different working fluids. Generation of power in space for terrestrial use can represent a great future opportunity: the low-temperature of space (~3 K), allows the attainment of very high efficiency even with low-temperature heat inputs, and the solar energy input is higher in spac...

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