A case study of sedimentation problems of Wadi Arbaat's dams reservoirs

Taha, Abubakr Taha Bakheit,Aldrees, Ali Techno-Press 2021 Advances in nano research Vol.11 No.5

The proper management of reservoir sedimentation is of critical importance for the sustainable development of surface water resources. Dams' reservoirs are losing their ability storage due to sedimentation processes worldwide. These losses vary from one reservoir to another depending on the characteristics of the watershed and water streams. Therefore, the performance of reservoirs is incredibly vulnerable. The area surrounding Red Sea State is under arid and semi-arid condition, and immensely suffering from a shortage of safe and reliable drinking water supplies. Wadi Arbaat is the primary source of water supply in Port Sudan city. Valleys mostly surround the Red Sea State and Wadi Arbaat suffer from a severe decline with the steep slope of 6-10 m/km. Therefore, the Wadi carries large quantities of sediments, which deposit in dams' reservoirs during the flood periods. The siltation strongly influences these dams and their reservoirs suffer from serious problems represented by increasing silting level and shortage in storage capacities. Consequently, this study aims to investigate the current situation and problems of the three existing dams and make a proper decision with a comprehensive and specific vision in the future. The main problems caused by reservoir sedimentation in the Red Sea Mountains are described as a reduction in the storage capacities, and entry of sediments into control structures such as sluice gates. The problems are further exacerbated as there is no guidance on the decision supports tool that is needed to underpin silting in the flood period and water resources management in these steep slope areas. The sedimentation processes, problems and changes of dam operation are discussed in this paper.

Incidence of apical crack formation and propagation during removal of root canal filling materials with different engine driven nickel-titanium instruments

Taha Özyürek,Vildan Tek,Koray Yılmaz,Gülşah Uslu 대한치과보존학회 2017 Restorative Dentistry & Endodontics Vol.42 No.4

Objectives: To determine the incidence of crack formation and propagation in apical root dentin after retreatment procedures performed using ProTaper Universal Retreatment (PTR), Mtwo-R, ProTaper Next (PTN), and Twisted File Adaptive (TFA) systems. Materials and Methods: The study consisted of 120 extracted mandibular premolars. One millimeter from the apex of each tooth was ground perpendicular to the long axis of the tooth, and the apical surface was polished. Twenty teeth served as the negative control group. One hundred teeth were prepared, obturated, and then divided into 5 retreatment groups. The retreatment procedures were performed using the following files: PTR, Mtwo-R, PTN, TFA, and hand files. After filling material removal, apical enlargement was done using apical size 0.50 mm ProTaper Universal (PTU), Mtwo, PTN, TFA, and hand files. Digital images of the apical root surfaces were recorded before preparation, after preparation, after obturation, after filling removal, and after apical enlargement using a stereomicroscope. The images were then inspected for the presence of new apical cracks and crack propagation. Data were analyzed with χ2 tests using SPSS 21.0 software. Results: New cracks and crack propagation occurred in all the experimental groups during the retreatment process. Nickel-titanium rotary file systems caused significantly more apical crack formation and propagation than the hand files. The PTU system caused significantly more apical cracks than the other groups after the apical enlargement stage. Conclusions: This study showed that retreatment procedures and apical enlargement after the use of retreatment files can cause crack formation and propagation in apical dentin.

Effects of a Static Synchronous Series Compensator (SSSC) Based on a Soft Switching 48-Pulse PWM Inverter on the Power Demand from the Grid

Taha Selim Ustun,Saad Mekhilef 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.1

In this paper the effects of a Static Synchronous Series Compensator, which is constructed with a 48-pulse inverter, on the power demand from the grid are studied. Extensive simulation studies were carried out in the MATLAB simulation environment to observe the compensation achieved by the SSSC and its effects on the line voltage, line current, phase angle and real/reactive power. The designed device is simulated in a power system which is comprised of a three phase power source, a transmission line, line inductance and load. The system parameters such as line voltage, line current, reactive power Q and real power P transmissions are observed both when the SSSC is connected to and disconnected from the power system. The motivation for modeling a SSSC from a multi-pulse inverter is to enhance the voltage waveform of the device and this is observed in the total harmonic distortion (THD) analysis performed at the end of the paper. According to the results, the power flow and phase angle can be controlled successfully by the new device through voltage injection. Finally a THD analysis is performed to see the harmonics content. The effect on the quality of the line voltage and current is acceptable according to international standards.

The effect of root canal preparation on the surface roughness of WaveOne and WaveOne Gold files: atomic force microscopy study

Taha Özyürek,Koray Yılmaz,Gülşah Uslu,Gianluca Plotino 대한치과보존학회 2018 Restorative Dentistry & Endodontics Vol.43 No.1

Objectives To examine the surface topography of intact WaveOne (WO; Dentsply Sirona Endodontics) and WaveOne Gold (WOG; Dentsply Sirona Endodontics) nickel-titanium rotary files and to evaluate the presence of alterations to the surface topography after root canal preparations of severely curved root canals in molar teeth. Materials and Methods Forty-eight severely curved canals of extracted molar teeth were divided into 2 groups (n = 24/each group). In group 1, the canals were prepared using WO and in group 2, the canals were prepared using WOG files. After the preparation of 3 root canals, instruments were subjected to atomic force microscopy analysis. Average roughness and root mean square values were chosen to investigate the surface features of endodontic files. The data was analyzed using one-way analysis of variance and post hoc Tamhane's tests at 5% significant level. Results The surface roughness values of WO and WOG files significantly changed after use in root canals (p < 0.05). The used WOG files exhibited higher surface roughness change when compared with the used WO files (p < 0.05). Conclusions Using WO and WOG Primary files in 3 root canals affected the surface topography of the files. After being used in root canals, the WOG files showed a higher level of surface porosity value than the WO files.

Pressure effects on dynamics behavior of multiwall boron nitride nanotubes

Taha Talebian 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.1

The dynamic behavior of Multiwall boron nitride nanotubes (MWBNNTs) is investigated by employing multiple elastic shells model. The influences of van der Waals interactions on layers are shown as nonlinear functions of the interlayer distance of MWBNNTs. Governingequations are solved by using the developed finite element method and by employing time history diagrams. The radial wavespeed from the outermost layer to the innermost layer is computed. The effects of geometrical factors such as diameter-to-thickness ratioon dynamic behavior of MWBNNTs are determined. The magnification aspects of MWBNNTs are computed, and the effects of surroundingpressures on wave speed and magnification aspect of MWBNNTs are discussed.

Electromagnetic Wave Absorption Properties of Core-Shell Ni/CuSiO3 Nanocomposite

Taha Latif,Rambabu Kuchi,Jong-Ryul Jeong 한국자기학회 2020 한국자기학회 학술연구발표회 논문개요집 Vol.30 No.1

Tardive Dyskinesia Associated with Bupropion

Taha Can Tuman,Uğur Çakır,Osman Yı ıd ldı ır rı ı m,Mehmet Akif Camkurt 대한정신약물학회 2017 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.15 No.2

Present report describes a 46 year old male patient with a diagnosis of major depression who developed tardive dyskinesia during bupropion therapy. Our patient had no history of neuroleptic use and his laboratory and neurologic examinations were normal. He had no family history of neurologic diseases. Although bupropion induced dyskinesia has been previously reported in the literature, it is rare and our case is the first case regarding tardive dyskinesia.

Hierarchical Control Scheme for Three-Port Multidirectional DC-DC Converters in Bipolar DC Microgrids

Taha Ahmadi,Mohsen Hamzeh,Esmaeel Rokrok 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

In this paper, a hierarchical control strategy is introduced to control a new three-port multidirectional DC-DC converter for integrating an energy storage system (ESS) to a bipolar DC microgrid (BPDCMG). The proposed converter provides a voltage-balancing function for the BPDCMG and adjusts the states of charge (SoC) of the ESS. Previous studies tend to balance the voltage of the BPDCMG buses with active sources or by transferring power from one bus to another. Furthermore, the batteries available in BPDCMGs were charged equally by both buses. However, this power sharing method does not guarantee efficient operation of the whole system. In order to achieve a higher efficiency and lower energy losses, a triple-layer hierarchical control strategy, including a primary droop controller, a secondary voltage restoration controller and a tertiary optimization controller are proposed. Thanks to the multi-functional operation of the proposed converter, its conversion stages are reduced. Furthermore, the efficiency and weight of the system are both improved. Therefore, this converter has a significant capability to be used in portable BPDCMGs such as electric DC ships. The converter modes are analyzed and small-signal models of the converter are extracted. Comprehensive simulation studies are carried out and a BPDCMG laboratory setup is implemented in order to validate the effectiveness of the proposed converter and its hierarchical control strategy. Simulation and experimental results show that using the proposed converter mitigates voltage imbalances. As a result, the system efficiency is improved by using the hierarchical optimal power flow control.

Hormonal Changes in Women Undergoing Bariatric Surgery: A Comparative Study with a Control Group

Taha Anbara 한국발생생물학회 2023 발생과 생식 Vol.27 No.3

Bariatric surgery is an effective treatment option for obesity, but its effects on reproductive hormones are not well understood. This study aimed to investigate the impact of bariatric surgery on estrogen and progesterone levels in women with obesity. This was a prospective study that included 87 women with obesity who underwent bariatric surgery and 87 control women with obesity who did not. Blood samples were collected at baseline and at 3-month and 6-month follow-up periods to measure reproductive hormones and Adiponectin as well as medical history and physical examination for endometriosis and polycystic ovary syndrome (PCOS). The study found that sleeve gastrectomy significantly increased follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels in the bariatric surgery group compared to the control group at 3 and 6-month follow-up. There was no significant difference in the mean levels of estrogen and progesterone between the two groups at the 3-month followup period. Bariatric surgery leads to significant weight loss in women with obesity, but it does not seem to have a significant impact on estrogen and progesterone levels in the short-term. Future studies with longer follow-up periods are needed to investigate the long-term effects of bariatric surgery on reproductive hormones

Users Involvement in New Product Development Process: A Designers' Perspectives

Taha, Zahari,Alli, Hassan,Rashid, Salwa Hanim Abdul Korean Institute of Industrial Engineers 2011 Industrial Engineeering & Management Systems Vol.10 No.3

The purpose of this paper is to study user's involvement in new product development (NPD). It seeks to identify the factors involving user and design practices in the design process of new product development. A survey was conducted on 20 respondents consisting of designers involved in product development from various industries. The study focused on the early activities of the product design process which is called product specification. The analysis performed considers the importance of involving users in design decision. The outcome of this research is the significance of involving users and its effect on product development activities. The research also provides a model for an integrated user, designer and product knowledge activity in the product development process.