Preferred Language
Articles
/
jbcd-2376
The Influence of Different Fabrication and Impression Techniques on the Marginal Adaptation of Lithium Disilicate Crowns (A comparative in vitro study)
...Show More Authors

Background: The marginal adaptation has a key role in the success and longevity of the fixed dental restoration, which is affected by the impression and the fabrication techniques .The objective of this in vitro study was to evaluate and compare the marginal fitness of lithium disilicate crowns using two different digital impression techniques (direct and indirect techniques) and two different fabrication techniques (CAD/CAM and Press techniques). Materials and Methods: Thirty two sound upper first premolar teeth of comparable size extracted for orthodontic reason were selected in this study .Standardized preparation of all teeth samples were carried out with modified dental surveyor to receive all ceramic crown restoration with 1 mm deep chamfer finishing line, 4 mm axial length and 6 degree convergence angle. Half of the teeth were duplicated and poured in type IV dental stone to have sixteen dies and then these dies and the remaining teeth divided in to two groups according to the type of digital impression techniques (n=16) as follow: Group A: Indirect digital impression technique scanned by inEos X5 camera; Group B: Direct digital impression technique scanned by CEREC AC Omnicam camera. Each group was subdivided according to the technique of fabrication into two subgroups (n=8): Press technique using IPS e-max press (A1, B1); CAD/CAM technique using IPS e-max CAD (A2, B2).Marginal gaps were evaluated on the prepared teeth at four defined points on each aspect using digital microscope at a magnification of (280X). One way ANOVA and LSD tests were used to identify and localize the source of difference among the groups. Results: The results showed that indirect digital impression with IPS e-max CAD/CAM group A2 revealed the poorest marginal integrity with (55.93 μm ± 3.300). Group B2 and group A1 were next in line with(44.49 μm ± 6.840 and 37.74 μm± 5.433) respectively, while in the first group of restorations, the result of 29.9 μm ± 5.534 obtained with direct digital impression with pressable ceramic was clearly better. Conclusions: All the tested digital impression techniques showed clinically acceptable accuracy and intraoral scanning with pressable ceramic significantly enhanced the marginal fit

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Sun May 01 2016
Journal Name
Journal Of Engineering
Production of Methyl Ester (Biodiesel) from Used Cooking Oils via Trans-esterification process
...Show More Authors

Used cooking oil was undergoing trans-esterification reaction to produce biodiesel fuel. Method of production consisted of pretreatment steps, trans-esterification, separation, washing and drying. Trans-esterification of treated oils was studied at different operation conditions, the methanol to oil mole ratio were 6:1, 8:1, 10:1, and 12:1, at different temperature 30, 40, 50, and 60 º C, reaction time 40, 60, 80, and 120 minutes, amount of catalyst 0.5, 1, 1.5, and 2 wt.% based on oil and mixing speed 400 rpm. The maximum yield of biodiesel was 91.68 wt.% for treated oils obtained by trans-esterification reaction with 10:1 methanol to oil mole ratio, 60 º C reaction temperature, 80 minute reactio

... Show More
View Publication Preview PDF
Publication Date
Wed Jun 01 2016
Journal Name
Journal Of Engineering
Accuracy Evaluation of Digital Elevation Model Created Using Handheld Global Positioning System Receivers
...Show More Authors

This study aims to assess the accuracy of digital elevation model (DEM) created with utilization of handheld Global Positioning System (GPS) and comparing with Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM), version 2. It is known that the quality of the DEM is affected by both of accuracy of elevation at each pixel (absolute accuracy) and accuracy of presented morphology (relative accuracy). The University of Baghdad, Al Jadriya campus was selected as a study area to create and analysis the resulting DEM. Additionally, Geographic Information System (GIS) was used to visualize, analyses and interpolate GPS track points (elevation data) of the study area. In this

... Show More
View Publication Preview PDF
Publication Date
Mon Sep 04 2023
Journal Name
2023 International Conference On Advanced Mechatronic Systems (icamechs)
Performance Analysis of Finite-Time Generalized Proportional Integral Observer for Uncertain Brunovsky Systems
...Show More Authors

This paper proposes a novel finite-time generalized proportional integral observer (FTGPIO) based a sliding mode control (SMC) scheme for the tracking control problem of high order uncertain systems subject to fast time-varying disturbances. For this purpose, the construction of the controller consists of two consecutive steps. First, the novel FTGPIO is designed to observe unmeasurable plant dynamics states and disturbance with its higher time derivatives in finite time rather than infinite time as in the standard GPIO. In the FTGPO estimator, the finite time convergence rate of estimations is well achieved, whereas the convergence rate of estimations by classical GPIO is asymptotic and slow. Secondly, on the basis of the finite and fast e

... Show More
View Publication
Scopus (10)
Crossref (7)
Scopus Crossref
Publication Date
Mon Jan 18 2021
Journal Name
Materials Science And Engineering
Properties of engineered cementitious composite concrete (bendable concrete) produced using Portland limestone cement
...Show More Authors

Bendable concrete, also known as Engineered Cementitious Composite (ECC) is a type of ultra-ductile cementitious composites reinforced with fibres to control the width of cracks. It has the ability to enhance concrete flexibility by withstanding strains of 3% and higher. The properties of bendable concrete mixes (compressive strength, flexural strength, and drying shrinkage) are here assessed after the incorporation of supplementary cementitious materials, silica fume, polymer fibres, and the use of ordinary Portland cement (O.P.C) and Portland limestone cement (IL). Mixes with Portland limestone cement show lower drying shrinkage and lower compressive and flexural strength than mixes with ordinary Portland cement, due to the ratio o

... Show More
Publication Date
Sun Dec 30 2018
Journal Name
Journal Of Engineering
Abrasive Wear Characteristics of Composite Material (AA 7075 / SiC) Synthesized by Stir Casting
...Show More Authors

Aluminum Metal Matrix Composites (ALMMCs) was prepared by using stir casting technique for AA 7075 aluminum alloy as a matrix reinforced with SiC particles at various percentages (3, 6, 9 and 12 wt. % ) and 75µm in grain size. The prepared composite material can be used for many applications such as aerospace, automobiles and many industrial sectors. Abrasive wear test was carried out by two stages: the first stage was done by changing the emery papers at various grit sizes 180, 320, 500, and 1000µm with constant applied load 15N. While the second stage was carried out by changing the applied loads 5, 10, 15, 20 and 25N with constant emery paper at 320 µm grit size. Microstructure examination, hardness test and roughn

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Mon Oct 03 2016
Journal Name
International Journal Of Civil Engineering
Development of Excess Pore Water Pressure around Piles Excited by Pure Vertical Vibration
...Show More Authors

View Publication
Scopus (18)
Crossref (13)
Scopus Clarivate Crossref
Publication Date
Mon Dec 04 2017
Journal Name
Al-qadisiyah Journal For Administrative And Economic Sciences
Survival Function Estimating of Single age Groups for Generalized Gamma Distribution with Simulation.
...Show More Authors

The analysis of survival and reliability considered of topics and methods of vital statistics at the present time because of their importance in the various demographical, medical, industrial and engineering fields. This research focused generate random data for samples from the probability distribution Generalized Gamma: GG, known as: "Inverse Transformation" Method: ITM, which includes the distribution cycle integration function incomplete Gamma integration making it more difficult classical estimation so will be the need to illustration to the method of numerical approximation and then appreciation of the function of survival function. It was estimated survival function by simulation the way "Monte Carlo". The Entropy method used for the

... Show More
Preview PDF
Publication Date
Mon Jul 30 2018
Journal Name
Civil Engineering Journal
Performance of Post-Fire Composite Prestressed Concrete Beam Topped with Reinforced Concrete Flange
...Show More Authors

The performance of composite prestressed concrete beam topped with reinforced concrete flange structures in fire depends upon several factors, including the change in properties of the two different materials due to fire exposure and temperature distribution within the composition of the composite members of the structure. The present experimental work included casting of 12 identical simply supported prestressed concrete beams grouped into 3 categories, depending on the strength of the top reinforced concrete deck slab (20, 30, and 40 MPa). They were connected together by using shear connector reinforcements. To simulate the real practical fire disasters, 3 composite prestressed concrete beams from each group were exposed to high t

... Show More
View Publication Preview PDF
Crossref (2)
Clarivate Crossref
Publication Date
Sun Mar 04 2018
Journal Name
Baghdad Science Journal
Biosorption of Safranin-O from Aqueous Solution by Nile Rose Plant (Eichhornia crassipes)
...Show More Authors

In this work Aquatic plant (Nile rose) was used to study adsorption of industrial dye (safranin-O from aqueous solution within several operation conditions. The dried leaves of Nile rose plant were used as adsorbents safranin-O from aqueous solution after different activations such as wet and dry enhancements. The data show increasing in dye solution removal percentage for both activation methods of the adsorbent and also dye removal percentage that was obtained by using adsorbent without any treatment with the progress contact time. The dye removal percentages at equilibrium time 40 minutes were 88.7% at non-activation, 92.3% at thermal activation, and 98.3% at acidic activation. The samples adsorbents before and after adsorption which wer

... Show More
View Publication Preview PDF
Scopus (10)
Crossref (4)
Scopus Clarivate Crossref
Publication Date
Wed Jan 01 2020
Journal Name
Biochemical Cellular Archives
Synthesis, characterizationand antibacterialactivity of PVA cyclic acetal (Cu) metal complex / chitosan polymer blend
...Show More Authors

Polyacetal was synthesized from the reaction of PVA with para-methyoxy benzaldehyde. Polymer metal complexwas prepared by reaction with Cu, polymer blend with Chitosan was prepared through the technique of solution casting method.All prepared compounds have been characterized through FT-IR, DSC, SEM as well as the Biological activity. The FT-IR results indicated the formation of polyacetal. The DSC results indicated the thermal stability regarding prepared polymer, polymermetal complex and Chitosan polymer blends. Antibacterial potential related to synthesized polyacetal, its metal complex andChitosan blend against four types of bacteria namely, Staphylococcus aureas, Psedomonas aeruginosa, Bacillus subtilis, Escherichia coli was examined a

... Show More
Preview PDF
Scopus