Design and simulation of a vertical broadband seismometer     

E. Habbak  H. Nofal  E. Lotfy  S. El-Sabban  Z. Nossair 《Arabian Journal of Geosciences》2016,9(5):408

In this paper, a new vertical broadband seismometer is designed, simulated, and evaluated. The proposed seismometer has a bandwidth from 40 s to 50 Hz and sensitivity to ground velocity of 1500 V’/m/s. The mechanical suspension used in the proposed design is a mass-leaf spring rotational pendulum. The displacement of the seismic mass is sensed by a laser interferometer and then forwarded to an electronic force feedback system which feeds a linear actuator to keep the mass almost fixed in its position. The current needed to fix the mass in its position is an indication of the ground acceleration. The performance of the simulated seismometer is evaluated by applying a data record of two actual earthquakes to the simulated model and comparing its response to the earthquakes with that of a real seismometer (Trillium-40) having the same bandwidth and sensitivity. The proposed seismometer has performed within 0.4 % residual variance for the local event and 0.03 % residual variance for the regional one compared to Trillium-40.  相似文献   

Measurements of total solar radiation at Giza     

El-Sabban  A. F.  Elnesr  M. K.  Firesah  A. M. 《Pure and Applied Geophysics》1960,45(1):298-302

Summary Records of total solar radiation on a horizontal surface has been obtained at the Agro-meteorological Station at Giza continuously since December 1, 1955 by means of a Robitzsch actinograph. The difficulties in obtaining precise measurements were described. The results of the first three years of record were discussed and summarized in tabular and graphical form. To such few years of observations, a 15 days moving average was applied. The new data were plotted so as to obtain the solar radiation pattern, which has been compared with the radiation received at the outer limits of the atmosphere and with the maximum probable radiation expected at the Station.  相似文献   

Cloudiness and sunshine duration measurements in the U.A.R.     

M. K. Elnesr  A. F. El-Sabban 《Pure and Applied Geophysics》1964,59(1):256-260

Summary Seasonal variations of cloudiness have been studied for the different zones of the United Arab Republic. It was found to be very low and to decrease more towards lower latitudes.From the records of a Campbell Stokes Sunshine recorder, installed at the Agro-meteorological Station at Giza, during a period of six years from 1956 to 1961, the monthly and daily variations of the hours of sunshine duration, have been also studied in detail and presented in a practical form.  相似文献