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.

The effects of autoclave sterilization on the cyclic fatigue resistance of ProTaper Universal, ProTaper Next, and ProTaper Gold nickel-titanium instruments

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

Objectives: It was aimed to compare the cyclic fatigue resistances of ProTaper Universal (PTU), ProTaper Next (PTN), and ProTaper Gold (PTG) and the effects of sterilization by autoclave on the cyclic fatigue life of nickel-titanium (NiTi) instruments. Materials and Methods: Eighty PTU, 80 PTN, and 80 PTG were included to the present study. Files were tested in a simulated canal. Each brand of the NiTi files were divided into 4 subgroups: group 1, as received condition; group 2, pre-sterilized instruments exposed to 10 times sterilization by autoclave; group 3, instruments tested were sterilized after being exposed to 25%, 50%, and 75% of the mean cycles to failure, then cycled fatigue test was performed; group 4, instruments exposed to the same experiment with group 3 without sterilization. The number of cycles to failure (NCF) was calculated. The data was statistically analyzed by using one-way analysis of variance and post hoc Tukey tests. Results: PTG showed significantly higher NCF than PTU and PTN in group 1 (p < 0.05). Sterilization significantly increased the NCF of PTN and PTG (p < 0.05) in group 2. PTN in group 3 had significantly higher cyclic fatigue resistance than PTN group 4 (p < 0.05). Also, significantly higher NCF was observed for PTG in group 2 than in groups 3 and 4 (p < 0.05). Conclusions: PTG instrument made of new gold alloy was more resistant to fatigue failure than PTN and PTU. Autoclaving increased the cyclic fatigue resistances of PTN and PTG.

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.

Evaluation of dental panoramic radiographic findings in edentulous jaws: A retrospective study of 743 patients “Radiographic features in edentulous jaws”

Taha Emre Kose,Nihat Demirtas,Hulya Cakir Karabas,Ilknur Ozcan 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.5

PURPOSE. The aim of this study was to determine the frequency of significant panoramic radiographic findings and eventual treatment requirements before conventional or implant supported prosthetic treatment in asymptomatic edentulous patients. MATERIALS AND METHODS. A total of 743 asymptomatic edentulous patients were retrospectively evaluated using a digital panoramic system. We analyzed the radiographic findings, including impacted teeth, retained root fragments, foreign bodies, severe atrophy of the posterior maxillary alveolar bone, mucous retention cysts, soft tissue calcifications and radiopaque?radiolucent conditions. RESULTS. Four-hundred-eighty-seven (65.6%) patients had no radiographic finding. A total of 331 radiographic findings were detected in 256 (34%) patients. In 52.9% (n=175) of these conditions, surgical treatment was required before application of implant-supported fixed prosthesis. However, before application of conventional removable prosthesis surgical treatment was required for 6% (n=20) of these conditions. CONCLUSION. The edentulous patients who will have implant placement for implant-supported fixed prosthesis can frequently require additional surgical procedures to eliminate pathological conditions.

Mitigation of Voltage Unbalances in Bipolar DC Microgrids Using Three-Port Multidirectional DC-DC Converters

Taha Ahmadi,Esmaeel Rokrok,Mohsen Hamzeh 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4

In this paper, a new three-port multidirectional DC-DC converter is proposed 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 charge of the ESS. Thanks to the multi-functional operation of the proposed converter, the conversion stages of the system are reduced. In addition, the efficiency and weight of the system are improved. Therefore, this converter has a significant capability when it comes to use in portable BPDCMGs such as electric DC ships. The converter modes are analyzed and small-signal models of the converter in each of the independent modes are extracted. Finally, comprehensive simulation studies are carried out and a BPDCMG laboratory prototype is implemented in order to verify the performance of the proposed voltage balancer using the burst mode control scheme.

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.

Structural control of hydrogeological aquifers in the Bahariya Oasis, Western Desert, Egypt

Taha Rabeh,Said Bedair,Mohamed Abdel Zaher 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.1

This work addresses the detection of aquifers and the delineation of subsurface structures predominant in the basement rocks and their relations with these aquifers at the Bahariya Oasis, Western Desert, Egypt, and the relationship between the subsurface structures and the aquifers. In this respect, land geomagnetic and geoelectric-reconnaissance surveys were carried out over the oasis. Additionally, wells and bore-hole logs were used to verify the results and to explore the distributions of the subsurface reservoirs and the geological sequences. The results illustrate that the main groundwater aquifers in the fractured limestone ranges from 40 m to 90 m in depth and in the saturated Nubian sandstone from 800 m to 1200 m in depth. The thickness of the Carbonate reservoir varies from 90 m to 160 m. The Nubian sandstone formation that unconformably overlies the basement rocks has a thickness of approximately 250 m. In general, the depth to the basement rocks ranges from 1.2 km and 2.9 km in certain local areas according to the magnetic data. The structure trend analyses show that the dominant tectonic trends are northeastward and northwestward. These structures play an important role in controlling the aquifer depths and most probably supply water from the deeper Nubian aquifer to the shallower Carbonate aquifer.

Impact of irregular marital cohabitation on quality of life and sexual dysfunction in infertile men from upper Egypt

Taha, Emad Abdelrhim,Sabry, Mohamed,Abdelrahman, Islam Fathy Soliman,Elktatny, Hossam,Hosny, Ahmed The Korean Society for Reproductive Medicine 2020 Clinical and Experimental Reproductive Medicine Vol.47 No.1

Objective: Irregular patterns of marital cohabitation are a common problem in upper Egypt due to employment conditions. The objective of this study was to investigate the effect of irregular marital cohabitation on the quality of life and sexual function of infertile men. Methods: In total, 208 infertile men were included and divided into two groups. The first group included 134 infertile men with an irregular pattern of marital cohabitation and the second group included 74 infertile men with a regular pattern of marital cohabitation. All subjects were assessed through a clinical evaluation, conventional semen analysis, the fertility quality of life (FertiQoL) questionnaire, the International Index of Erectile Function (IIEF-5) score, and the premature ejaculation diagnostic tool (PMEDT). Results: The two groups were compared in terms of conventional semen parameters, FertiQoL, IIEF-5 score, and PMEDT. Infertile men with an irregular pattern of marital cohabitation had significantly lower subscale and total FertiQoL and IIEF-5 scores. Additionally, they had significantly higher PMEDT scores. Erectile dysfunction and premature ejaculation were more common in them than in infertile men with a regular pattern of marital cohabitation. Conclusion: Irregular patterns of marital cohabitation had an adverse effect on quality of life and sexual function in infertile men.

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.

Effect of adaptive motion on cyclic fatigue resistance of a nickel titanium instrument designed for retreatment

Taha Özyürek,Koray Yılmaz and Gülşah Uslu 대한치과보존학회 2017 Restorative Dentistry & Endodontics Vol.42 No.1

Objectives: The aim of this study was to evaluate the cyclic fatigue resistance of the ProTaper Universal D1 file (Dentsply Maillefer) under continuous and adaptive motion. Materials and Methods: Forty ProTaper Universal D1 files were included in this study. The cyclic fatigue tests were performed using a dynamic cyclic fatigue testing device, which had an artificial stainless steel canal with a 60° angle of curvature and a 5 mm radius of curvature. The files were randomly divided into two groups (Group 1, Rotary motion; Group 2, Adaptive motion). The time to failure of the files were recorded in seconds. The number of cycles to failure (NCF) was calculated for each group. The data were statistically analyzed using Student’s t-test. The statistical significant level was set at p < 0.05. Results: The cyclic fatigue resistance of the adaptive motion group was significantly higher than the rotary motion group (p < 0.05). Conclusion: Within the limitations of the present study, the ‘Adaptive motion’ significantly increased the resistance of the ProTaper Universal D1 file to cyclic facture.