Effect of anatomic, semi-anatomic and non-anatomic occlusal surface tooth preparations on the adaptation of zirconia copings

Mohammed Jameel Hefne,Waleed Asiri,Syed Rashid Habib 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.6

PURPOSE To compare the accuracy of marginal and internal adaptation of zirconia (Zr) copings fabricated on anatomic (A), semi-anatomic (SA) and non-anatomic (NA) occlusal surface preparations. MATERIALS AND METHODS 45 extracted bicuspid teeth were prepared for receiving zirconia crowns, with different occlusal preparation designs A=15, SA=15 & NA=15. The Zr copings were fabricated by using CAD4DENT, CAD/CAM. The copings were adjusted, cemented and were cross sectioned centrally from buccal cusp tip to lingual cusp tip into mesial and distal halves. The copings were examined under electron microscope at ×200 magnification and the measurements were recorded at 9 predetermined areas in micrometers. RESULTS Overall mean gap values for the three groups was found to be 155.93±33.98 µm with Anatomical Occlusal preparation design having the least gap value of 139.23±30.85 µm showing the best adaptation among the groups. Post Hoc Tukey's test showed a statistically significant difference (P=.007) between the means of gap for A & NA preparation designs. Measurements recorded at 9 predetermined points showed variations for the three groups. CONCLUSION Anatomical occlusal preparation designs resulted in better marginal and internal adaptation of Zr copings. There is a considerable variation between the measured marginal and internal gap values for the Zr copings fabricated by the (CAD4DENT-CAD/CAM). This variation may be associated with the lack of standardization of the preparation of teeth, computerized designing of the coping for each tooth, cement used, uniform pressure application during the cementation of the copings, sectioning of the copings and the microscopic measurements.

Effect of Moorings Drag and Inertia on Response of Spar Platform

Mohammed Jameel,Abdulrahman Eyada Ibrahim,SuhailAhmad,Mohd Zamin Jumaat 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.7

Spar platform is a type of floating structure utilized for oil and gas exploration and production in deep and ultra-deep waters. Coupled analysis in present study considers Spar mooring lines as an integrated system. It incorporates the contribution of drag and inertia forces of mooring lines. A rigid classical Spar cylinder connected by four tensioned catenary mooring lines has been modeled and analysed using finite element approach. Mooring system has been modeled as hybrid beam elements. The Studies cover surge, heave, pitch and mooring line tension responses, highlighting the coupling effect. The non-linearities present in the coupled system leads to irregular behavior under regular sea states. The coupled model noticeably confirms its importance in terms of hydrodynamic damping on mooring system. There is a key variance in behavior found with and without drag and inertia forces on mooring system.

Seismic Analysis of Roller Compacted Concrete (RCC) Dams Considering Effect of Sizes and Shapes of Galleries

Khaled Ghaedi,Mohammed Jameel,Zainah Ibrahim,P. Khanzaei 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.1

This paper compares the analysis of a Roller Compacted Concrete (RCC) dam with and without galleries under seismic loading. The effects of different sizes and shapes (circle, octagon and square) of gallery have also seen in the analysis. For this purpose, twodimensional (2D) Finite Element Model (FEM) is used for nonlinear dynamic analysis by means of finite element software, ABAQUS. In addition, Concrete Damaged Plasticity (CDP) model is also implemented to inspect the tensile damage of the dam during earthquake excitation. Kinta RCC dam of Malaysia is considered as a case study in analysis. From the seismic analysis, it was found that by increasing the size of openings, stress is developed around the galleries. As a result, the gallery with circle shape is more appropriate for the dam in comparison to gallery with square and octagon shapes. From crack propagation analysis and displacement response, it was also found that the gallery with circle shape behaves better than the gallery with square and octagon shaped.

Wind induced response of Spar-mooring-riser system

Abdulrahman Eyada Ibrahim,Mohammed Jameel 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

In recent decades, the exploitation of hydrocarbon reservoirs under the seas and oceans has been regarded as a viable alternative. Several types of floating structures are utilized in deep and ultra-deep water oil and gas exploration and production. Spar platforms arethe most recent type of platforms to be designed and utilized in deep water environments. This type of platform is an assemblage of acylindrical hull, moorings and risers that responds to hydrodynamic and aerodynamic loads in a complex manner. Coupled behaviours ofspar–mooring–riser system influenced by the wind load in random wave environment have been studied using coupled analysis method. The spar–mooring–riser system has been analysed to predict system responses induced by wind action under a long crested randomwave using finite element approach. Wind load induces a significant shift in the spar position away from its original place in the randomsea state in addition to a notable heave motion reduction. The top tension magnitude of the moorings and riser significantly increased. The diminishing fluctuation highlights the firmness and controlled oscillations of the spar platform relative to its new mean position.

Experimental Study on Strength Gaining Characteristics of Concrete using Portland Composite Cement

Md. Alhaz Uddin,Mohammed Jameel,Habibur Rahman Sobuz,Md. Shahinul Islam,Noor Md. Sadiqul Hasan 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.4

This study deals with experimental investigation of strength gaining characteristics of concrete made with Portland Composite Cement (PCC) and Ordinary Portland Cement (OPC). Compressive strength of concrete is often considered as a measure to determine the rate of strength gain of concrete with age and different cement composition. Strength developments of five concrete types have been investigated in terms of cement content and curing duration. Experimental observations on 495 specimens reveal that the early age strength of PCC concrete is lower than that of OPC concrete. Based on the test results, lack of proper pozzolanic reaction in the presence of fly ash in PCC concrete strength is lower at early age. The pozzolanic activity of fly ash also contributes to the strength gain at later stages of continuous curing. This study also concludes that drying ambient conditions reduce the strength potential of PCC concrete as the secondary (pozzolanic) reaction fails to contribute to the development of strength.

Bolted connections to tubular columns at ambient and elevated temperatures - A review

N.H. Ramli Sulong,S.H. Leong,Mohammed Jameel 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.2

Tubular column members have been widely adopted in current construction due to its numerous advantages. However, the closed-section profile characteristics of tubular columns severely limit the connection possibilities. Welding type is acceptable but discouraged because of on-site issues. Blind-bolted connection is preferable because of its simplicity, economic benefit, and easy assembly. This paper presents a state-of-the-art review on bolted connections to tubular columns for bare steel tubes, including square and circular sections. Available studies on bolted connections at ambient and elevated temperatures are reviewed, but emphasis is given on the latter. Various methods of determining the connection performance through experimental, analytical, component based, and finite element approaches are examined. Future research areas are also identified.

Effect of Axial Restraints on Top-Seat Angle Connections at Elevated Temperatures

Leong Siong Hean,N.H. Ramli Sulong,Mohammed Jameel 대한토목학회 2016 KSCE Journal of Civil Engineering Vol.20 No.6

In this study, a finite element model of a top-seat angle connection at elevated temperature is developed to study the effect of axial restraints on the connection behavior. Models are first validated with existing fire test results of top-seat angle connection. Non-linear behavior of the materials was modeled with the definition of elastic-plastic multi-linear properties and frictional contact between surfaces is included to simulate actual conditions. Validation of the model behavior shows that the model is in good agreement with existing experimental results and therefore the model is used for further study on the effect of axial restraints towards connection behavior. Both isothermal and anisothermal conditions were analyzed considering the effect of axial restraints. Results from the model shows that an increase in axial restraints has increased connection capacity while the stiffness remains similar for low axial levels. On the other hand, the shrinkage of the beam, may lead to tensional axial loads, causing axial pulling on the connection, resulting in higher deformation and different deformation patterns of the component angle sections. Effect on the design guidelines for connection design with axial restraints provided by Eurocode 3:2005 (Part 1-8) is also discussed at the end.

Effect of anatomic, semi-anatomic and non-anatomic occlusal surface tooth preparations on the adaptation of zirconia copings

Habib, Syed Rashid,Asiri, Waleed,Hefne, Mohammed Jameel The Korean Academy of Prosthodonitics 2014 The Journal of Advanced Prosthodontics Vol.6 No.6

PURPOSE. To compare the accuracy of marginal and internal adaptation of zirconia (Zr) copings fabricated on anatomic (A), semi-anatomic (SA) and non-anatomic (NA) occlusal surface preparations. MATERIALS AND METHODS. 45 extracted bicuspid teeth were prepared for receiving zirconia crowns, with different occlusal preparation designs A=15, SA=15 & NA=15. The Zr copings were fabricated by using CAD4DENT, CAD/CAM. The copings were adjusted, cemented and were cross sectioned centrally from buccal cusp tip to lingual cusp tip into mesial and distal halves. The copings were examined under electron microscope at ${\times}200$ magnification and the measurements were recorded at 9 predetermined areas in micrometers. RESULTS. Overall mean gap values for the three groups was found to be $155.93{\pm}33.98{\mu}m$ with Anatomical Occlusal preparation design having the least gap value of $139.23{\pm}30.85{\mu}m$ showing the best adaptation among the groups. Post Hoc Tukey's test showed a statistically significant difference (P=.007) between the means of gap for A & NA preparation designs. Measurements recorded at 9 predetermined points showed variations for the three groups. CONCLUSION. Anatomical occlusal preparation designs resulted in better marginal and internal adaptation of Zr copings. There is a considerable variation between the measured marginal and internal gap values for the Zr copings fabricated by the (CAD4DENT-CAD/CAM). This variation may be associated with the lack of standardization of the preparation of teeth, computerized designing of the coping for each tooth, cement used, uniform pressure application during the cementation of the copings, sectioning of the copings and the microscopic measurements.

Applications of the ANFIS and LR in the prediction of strain in tie section of concrete deep beams

Mohammad Mohammadhassani,Hossein Nezamabadi-Pour,Mohammed Jameel,Karim Garmasiri 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.12 No.3

Recent developments in Artificial Intelligence (AI) and computational intelligence have made it viable in the construction industry and structural analysis. This study usesthe Adaptive Network-based Fuzzy Inference System (ANFIS) as a modelling tool to predict the strain in tie section for High Strength Self Compacting Concrete (HSSCC) deep beams. 3773 experimental data were collected. The input data andits corresponding strains in tie section as output data were recorded at all loading stages. Results from ANFIS are compared with the classical linear regression (LR). The comparison shows that the ANFIS‘s results are highly accurate, precise and satisfactory.

Application of the ANFIS model in deflection prediction of concrete deep beam

Mohammad Mohammadhassani,Hossein Nezamabadi-Pour,MohdZamin Jumaat,Mohammed Jameel,S.J.S.Hakim,Majid Zargar 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.3

With the ongoing development in the computer science areas of artificial intelligence and computational intelligence, researchers are able to apply them successfully in the construction industry. Given the complexities indeep beam behaviour and the difficulties in accurate evaluation of its deflection,the current study has employed the Adaptive Network-based Fuzzy Inference System (ANFIS) as one of the modelling tools to predict deflection for high strength self compacting concrete (HSSCC) deep beams. In this study, about 3668measured data on eight HSSCC deep beams are considered. Effective input data and the corresponding deflection as output data were recorded at all loading stages up to failure load for all tested deep beams. The results of ANFIS modelling and the classical linear regression were compared and concluded that the ANFIS results are highly accurate, precise and satisfactory.