Browsing by Subject "Drainage"
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Item Soil-particle and pore orientations during drained and undrained shear of a cohesive sandy silt-clay soil(2004) Cetin H.; Söylemez M.The orientations of particles, pores, and other constituents of an artificially made cohesive sandy silt-clay soil were studied to investigate how they change during drained and undrained shear. The results show that the orientation pattern before shearing is nearly random, although there may be some degree of preferred orientation caused by the overburden pressure. The degree of preferred orientation increases as the shearing increases until failure in both the drained and undrained tests and increases towards the failure plane. After failure, the degree of preferred orientation does not change considerably near the failure plane but does continue to increase away from it. The number of oriented particles, pores, and other constituents increases, but their averages stay about the same as the shearing continues after failure in the drained tests. The differences between the degrees of preferred orientations 5 and 10 mm away from the failure planes at different shear (horizontal) displacements are much less in the drained tests than in the undrained tests, indicating formation of a wider deformation zone in the drained tests. This is probably because particles in the drained tests have enough time to respond to the applied shear stresses and change their orientation. This may explain why deformations occur in wide zones along tectonically active creeping (aseismic) faults, whose mechanisms are analogous to those of drained shear tests, and in narrow zones along seismic faults, whose mechanisms are analogous to those of undrained shear tests. © 2004 NRC.Item Assessment of retention basin volume and outlet capacity in urban stormwater drainage systems with respect to water quality(Indian Academy of Sciences, 2005) Yurdusev M.A.; Kumanlioǧlu A.A.; Soemaz B.The quality of river water or other surface waters is detrimentally affected by the contaminants carried by the rainfall runoff in urban areas. The control of pollution moved by rainfall runoff is achieved by installing outlets and small retention basins in stormwater collection systems, thereby allowing only a certain amount of rainfall water to overflow and leading the remaining to treatment plants. This study analyses the effect of concentration time on surface water pollution caused by rainfall runoff. For this purpose, a linear S-curve is assumed for the flow hydrograph arising from the collection system, based on parameters of rainfall considered and the catchment area. An independent code is developed to analyse such a system and this is applied to an urban area using nine-year single-discrete rainfall records of Izmir Station, Turkey. The system is capable of tackling situations where there is only a basin or a basin with outlet.Item Are drains useful for lumbar disc surgery? A prospective, randomized clinical study(2006) Mirzai H.; Eminoglu M.; Orguc Ş.OBJECTIVE: In this prospective, observer-masked clinical study, we evaluated if insertion of a drain had a significant role in decreasing the existence and the size of postoperative epidural hematoma, which is believed to be a factor causing epidural fibrosis in patients undergoing lumbar discectomy. METHOD: Fifty patients undergoing lumbar disc surgery were randomly assigned to two groups: with or without insertion of a drain in the epidural space. A drain was inserted in 22 patients, whereas 28 were left without a drain. All patients were evaluated, by means of magnetic resonance imaging (MRI) on the first postoperative day, specifically looking for the existence and the size of epidural hematoma. The size of epidural hematoma was graded as none, minimal, moderate, or prominent. The patients were clinically examined preoperatively and at the follow-up of 6 months by Oswestry Disability Index and recurrence of pain. A follow-up MRI was repeated at 6 months, and the subsequent development of epidural fibrosis was evaluated. RESULTS: Epidural hematoma was detected in 36% of patients with a drain and in 89% of patients without a drain (P=0.000). There were significant less number of minimum, moderate, and prominent sized hematomas in the group with a drain (P=0.000). On the 6-month follow-up, epidural fibrosis was found in 58.3% of patients without a drain and in 31.6% of patients with a drain (P=0.08). Late clinical outcome (improvement in Oswestry Index and no recurrent pain) was better in the group with drain, but not statistically significant (P=0.4). CONCLUSIONS: Occurrence of hematoma in the epidural space is common after lumbar disc surgery even if meticulous hemostasis has been achieved. Insertion of a drain decreases both the incidence and the size of hematoma on the first postoperative day as detected by MRI. This may have practical implications for the prevention of significant postoperative fibrosis and obtaining better surgical outcome. Copyright © 2006 by Lippincott Williams & Wilkins.Item Giant hydronephrosis(eScholarship, 2014) Golcuk Y.; Ozsarac M.; Eseroglu E.; Yuksel M.B.[No abstract available]Item Palliative Biliary Drainage Has No Effect on Survival in Pancreatic Cancer: Medical Oncology Perspective(Springer, 2022) Erdoğan A.P.; Ekinci F.; Yıldırım S.; Özveren A.; Göksel G.Purpose: Removal of obstructive jaundice in metastatic pancreatic cancer is an important part of palliative therapy. However, it is not known whether invasive procedures reduce cancer-related mortality. In this study, the effect of palliative biliary drainage on survival outcomes in pancreatic cancer patients was evaluated. Methods: Patients diagnosed with pancreatic cancer and undergoing biliary drainage in two different centers between 2010 and 2019 were evaluated retrospectively. Results: Biliary drainage was applied to 73 patients, constituting 20.6% of 355 patients included in the study. The median progression-free survival (PFS) of patients with biliary stent was 5 months, while the median PFS of patients without stenting was 5.5 months and the median overall survival (OS) was 11.1 and 11.5 months, respectively (p: 0.424, p: 0.802). Conclusions: A positive effect of palliative biliary drainage on median PFS and OS could not be demonstrated in our study group. In pancreatic cancer, predictive markers are needed to select patients who can derive a survival benefit from biliary drainage. © 2021, Springer Science+Business Media, LLC, part of Springer Nature.