In this paper, the effect of different curvatures on the spatial variation of coherent flow structure inside two physical models with both strongly curved and mild multibend meanders is investigated. Three dimensional flow velocities at three sequential meanders were measured using an Acoustic Doppler Velocity meter (Micro-ADV). Three dimensions of flow velocity are classified into two major classes and eight different bursting events. The contribution probability and transition probability of each zone is calculated from experimental data. The results indicated that the effect of curvature in sequential bends was important particularly for strongly curved bends. The contribution probability of the events for strongly curved meanders with relative curvature (R c /B) of 2.6 were found to be higher than for mild curved meanders with relative curvature (R c /B) of 4.43. The minimum contribution probability was found in external inward interaction event. In addition, analysis of bursting events showed that the highest values of transition probabilities occurred in the stable organizations for both models. The influences of different curvatures on distributions of the Reynolds shear stress, the turbulent kinetic energy, the streamwise velocity and the vertical velocity were also shown to be in good agreement with eroded bed.The above results can be useful for finding meandering patterns inside rivers and also in river training works.

No abstract

No abstract

Eighty-five cases of hepatic hydatid cysts were exam· ined by ultrasonography. On the basis of sonographic patterns (as well as clinical symptomatology and surgical, bacteriologic, and pathologic findings), four groups of cysts were identified: uninfected, organizing, suppurative, and degenerated. A specific sign is defined to differentiate hydatid cysts from cystic lesions of other types. Organizing cysts are defined and ways to differentiate them from infected cysts sonographically are I nfestation by Echinococcus granulosus is a major diagnostic and therapeutic problem in many parts of the cattle+raising regions of the world. Successful surgical management of the disease is dependent on accurate diagnostic knowledge of the status, number, and location of the parasites in a particular abdominal organ. In recent years, ultrasonography has been proven effective in diagnosing hepatic hydatid cysts.1~ The purpose of this study is to report our experience with 85 cases of hepatic hydatid cysts and describe some new features. These include: 1) "double line" sign reflecting the pericyst and the laminated membrane of the cyst, which is thought to be a specific diagnostic sign in differentiating hydatid cysts from cysts of other types; 2) sonographic findings helpful in differentiating the orga· nizing hydatid cysts from the infected cysts; 3) analysis of the echogenic material between the daughter cysts, previously described as "matrix" 7 (cysts with abundant discussed. An analysis was made of the echographically detected material between the daughter cysts previously referred to as "matrix. 7:443, 1988) matrix may mimic solid lesions 1 • 9 ); and 4) some clues in differentiating suppurative hydatid cysts from abscesses. Finall}'t a sonographic classification of the hydatid cyst that correlates the pathology with the life cycle of the parasite is proposed. Our findings apply only to E. granulosus and not to E. alveolaris, another species of this parasite. MATERIALS AND METHODSEighty-five patients with hydatid cyst were examined between September 1984 and August 1986. The patients were examined by commercially available real-time equipment (Hitachi, EUB-26 and EUB-40). The reasons for the sonographic studies were hepatomegaly and the presence of abdominal masses (either alone or associated with symptomatology related to infection or jaundice). The patients were classified into four groups on the basis of clinical symptomatology, sonographic pat- parasite-the scolices-and the cyst is consadered fer-

No abstract