Nonlinear oscillations control. Energy invariants

In this paper, the synthesis of control laws for nonlinear oscillatory systems based on introduction of energy invariants in the state space of synthesized systems is considered. Control problems for pendulum systems, including the “inverted pendulum” problem formulated by P.L. Kapitsa, are considered. New types of unified nonlinear oscillators are synthesized.     

F-18 FDG whole-body positron emission tomography scan in primary breast sarcoma

Three patients with primary breast sarcoma showed intense F-18 FDG breast uptake on the whole-body scan. In two patients the uptake was irregular and associated with cold foci that corresponded to hypodense lesions noted on the chest CT; these represented areas of pathologically demonstrated tumor necrosis. There was also intense FDG uptake in pulmonary, axillary, and supraclavicular lymph node metastases. All lesions were confirmed by CT scan of the chest. Thus F-18 FDG positron emission tomographic scanning accurately staged the tumors in these two patients, and it documented local recurrence in the third patient. Histopathologic examination showed evidence of a high-grade sarcoma, a primary rhabdomyosarcoma, and a malignant cystosarcoma phyllodes of the breast. Similar to breast carcinoma, F-18 FDG whole-body positron emission tomographic imaging could be useful in diagnosing and staging primary breast sarcomas.     

Short-term peak demand forecasting in fast developing utility withinherit dynamic load characteristics. I. Application of classicaltime-series methods. II. Improved modelling of system dynamic loadcharacteristics

Estimates of the peak demand pertaining to a typical fast-growing system with inherit dynamic load characteristics are derived from three classical time-series forecasting methods. These demand estimates are compared with corresponding actual values. It is shown that application of sophisticated technological classical forecasting techniques to the forecasting problem of a typical fast-growing utility with dynamic load characteristics gives peak demand forecasts with varying degree of accuracy over the forecasting periods considered. This is mainly due to the inherent inability of these methods to simulate the complex load characteristics arising from the interactions of seasonality, trend, and cyclic moving special events. An attempt is made to isolate the effects of these events and to separately forecast the static and dynamic components of the system demand. The accuracy of the forecasted demand thus obtained is comparatively better than that of the forecast obtained     

CATALYTIC HYDROTREATMENT OF PETROLEUM RESIDUE

Iraqi reduced crude (350°C+) with a sulfur content of 4.3 wt% and a total metal content (Ni+V) of 141 WPPM was n-heptane deasphalted at specified conditions. The deasphalted oil (97.2 wt% of original residue) contains 4.1 wt% of sulfur and 103 ppm of metal. The original reduced crude and deasphalted oil were hydrotreated on a commercial Ni-Mo-alumina catalyst presulfided at specified conditions in a laboratory trickle-bed reactor. The reaction temperatures varied from 300 to 420°C with the liquid hourly space velocity (LHSV) ranging from 0.37 to 2.6 h^-1. Hydrogen pressure was kept constant throughout the experiments at 6.1 MPa, with a hydrogen/oil ratio of about 300 NLL^-1 (normal liters of hydrogen per liter of feedstock). Analysis for sulfur, nickel, vanadium and n-pentane asphaltenes were carried out for hydrotreated products from both the original residue and the deasphalted oil. The comparison of the results obtained for the hydrotreatment of deasphalted oil and original reduced crude indicates that the removal of sulfur, nickel and vanadium was higher for the deasphalted oil than those obtained for the non-deasphalted residue over the entire range of conversion. The exclusion of extremely high molecular weight asphaltenes by n-heptane deasphalting seems to improve the access of oil into catalyst pores resulting in higher desulfurization and conversion of the lower molecular weight asphaltenes. The sulfur content of n-pentane precipitated asphaltenes remained unchaneed with LHSV for various temperature for hydrotreated products produced from both deasphalted oil and original reduced crude.     

Release of furosemide from sustained release microcapsules prepared by phase separation technique

Furosemide Eudragit RL-100 sustained release microcapsules were prepared using phase separation technique. The results of the release studies, in sorensen phosphate buffer at PH 7.4, indicated good sustained release of the prepared microcapsules. Increasing drug to polymer ratio resulted in a decrease in the release, while increased release obtained by increasing the PH of the dissolution medium. Dosing of healthy human volunteers with sustained release microcapsules resulted in a reduced and sustained urine volume compared to the profuse diuresis obtained with the conventional furosemide capsules.     

A new video compression algorithm for different videoconferencing standards

In this paper, a new and simple predictive coding algorithm for video compression and multimedia communication for different network applications is investigated. This algorithm is called semi‐hexagonal absolute moment block truncation coding (SH‐AMBTC). It enjoys better objective and subjective qualities over the standard square shaped AMBTC. This technique based on the prediction of the bit‐map of the middle frames in a sequence from the bit‐map of the end frames (the first and the last frames in the group). It is of very low complexity comparing to the standard algorithm MPEG. The new algorithm adds no complexity to the existing AMBTC algorithm. Copyright © 2002 John Wiley & Sons, Ltd.