The paper preseiits an investigation on vibrations of mechanical systems arising from unbalanced masses. At the experimental stage, a power transmission shaft is driven at different operating speeds, therefore, the paranieters, such as displacement, velocity and acceleration in vertical direction due to body vibrations are measured at various points on the frame before and after balancing. Balancing has provided a definite decrease in the amplitudes of vibration parameters.
In addition to these studies mentioned above, the use of Neural Network (NN) for vibration analysis of a frame due to unbalanced transmission shaft is also achieved. The results show that the NN approach exactly follows the foregoing results. This implies the necessity of the non-linear modelling capabilities of the NN for vibration problems of mechanical systems.
For the last decade the Egyptian government has planned to implement the Tushka project at the southeastern part of the western Desert. This project includes the construction of a number of new cities. Tushka New City is one of these cities. Tushka area has a complex tectonic and geological history. Although no historical earthquakes are known to have occurred in the Tushka area, five large earthquakes of magnitude between 5.1 and 6.2 were recently observed from four active zones located around Tushka area. In addition to these four zones many microearthquakes have been detected in and around Tushak area. The main purpose of this research is to elucidate the seismicity and estimate the seismic hazard due to this activity in the study area. According to the spatial distribution of earthquakes that located in and around the study area, 9 seismic zones are defined on the seismotectonic map. For each seismic zone the seismic hazard parameters are estimated and used as input data for seismic hazard analysis. The resulting probability distributions are taken to produce iso-acceleration map for specific periods and economic life of public structures. The hazard at the proposed Tushka New City site is given by the hazard curve that is represented by the relationship between the peak ground acceleration and its annual exceedance probability. The maximum peak ground acceleration is 49, 137, 157 and 177 cm/s2 (gal) for zones Z-1, Z-6, Z-9 and Z-4 respectively. Although the values of PGA in zones Z-4, Z-6 and Z-9 are almost the same, Z-4 has a significant effect on the proposed Tushka New City site due to its location about 140 km northeast to the study area, while the calculated maximum acceleration with 90 percent probability of not being exceeded in 50 years of exposure time (475 years return period) at the proposed Tushka New City site was about 22 cm/s2., Raafat E. Fat-Helbary, Hussein M. El Khashab, Dragi Dojcinovski, Karrar O. El Faragawy and Abdel-nasser M. Abdel-Motaal., and Obsahuje bibliografii
From the temporal perspective, this article examines shifts in the production of sociological knowledge. It identifies two kinds of rhythms of sociology: 1) that of sociological standpoints and techniques of investigation and 2) that of contemporary academic life and culture. The article begins by discussing some of the existing research strategies designed to “chase” high-speed society. Some, predominantly methodological, currents are explored and contrasted with the “slow(er)” instruments of sociological analysis composed of different, yet complementary, modes of inquiry. Against this background, the article stresses that it is through the tension between fast and slow modes of inquiry that sociology reproduces itself. The subsequent part explores the subjective temporal experience in contemporary academia. It is argued that increasing administration and auditing of intellectual work signifi cantly coshapes sociological knowledge production not only by requiring academics to work faster due to an increasing volume of tasks, but also by normalizing time-pressure. The article concludes by considering the problem as to whether the increasing pace of contemporary academic life has detrimental consequences for the more organic reproductive rhythms of sociology., Tento článek zkoumá proměny produkce sociologického vědění, a to z perspektivy temporality (časovosti). Odlišuje dva druhy sociologických rytmů: první souvisí se sociologickými hledisky and technikami zkoumání, druhý potom se současnou podobou akademické kultury. Článek se nejprve zabývá několika existujícími výzkumnými strategiemi určenými ke „stíhání“ vysokorychlostní společnosti. Některé, především metodologické proudy jsou podrobeny diskuzi a porovnány s „pomalými/pomalejšími“ nástroji sociologické analýzy, sestávajících se z odlišných, avšak komplementárních způsobů šetření. V této souvislosti článek zdůrazňuje, že napětí mezi rychlými a pomalými způsoby šetření tvoří reprodukční předpoklady sociologie. Následující část se zabývá subjektivní časovou zkušeností v podmínkách soudobého akademického světa. Článek tvrdí, že zvyšující se adp ministrativa a auditování intelektuální práce značně spoluutváří výrobu sociologického vědění; a to nejen proto, že akademičtí pracovníci jsou díky vzrůstajícímu počtu úkolů nuceni pracovat rychleji, ale také kvůli normalizaci časového tlaku. Závěrem je pojednáno o tom, do jaké míry lze tvrdit, že tempo současného akademického života má neblahé důsledky pro organické reprodukční rytmy sociologie., and Filip Vostal.