Background: This study was performed to compare the marginal fit changes and facture resistance of metal ceramic crowns constructed from Ceramill Sintron metal coping veneered with three different porcelain veneering materials (Vita Master Koromikos VMK, Willi Geller Creation CC and GC initial MC), also to evaluate the influence of thermocycling on load at fracture. Materials and Methods: Master brass die was scanned ,then metal coping was designed and milled from Ceramill Sintron blank to get 60 metal copings, then divided randomly into three groups(20 sample), then veneered with porcelain: VITA, Creation or GC. The marginal gaps were measured before and after porcelain veneering then marginal fit changes was calculated. Fracture resistance test was done by Instron®, the master die was duplicated to sixty analogs then each analog was fixed into acrylic base. After that each crown was cemented onto the corresponding die analog. Ten samples of each group were subjected to compressive loading to fracture and other ten subjected to thermocycling followed by compressive loading to fracture. Result and Conclusion: The result of marginal fit changes showed that GC group had the lowest marginal gap follow by VITA and Creation. While VITA group showed the highest fracture resistance follows by GC then Creation. Thermocycling process did not significantly reduce the load at fracture for all groups.
An experiment was carried out to study the effect of soil organic carbon (SOC) and soil texture on the distance of the wetting front, cumulative water infiltration (I), infiltration rate (IR), saturated water conductivity (Ks), and water holding capacity (WHC). Three levels ( 0, 10, 20, and 30 g OC kg-1 ) from organic carbon (OC) were mixed with different soil materials sandy, loam, and clay texture soils. Field capacity (FC) and permanent wilting point (PWP) were estimated. Soil materials were placed in transparent plastic columns(12 cm soil column ), and water infiltration(I) was measured as a function of time, the distance of the wetting front and Ks. Results showed that advance we
In this work, prepared new ligand[3- (1H-indol-3-yl) -2- (3-(4- methoxybenzoyl)thiouereido) propanoic acid](MTP) has been synthesized by reaction of 4-Methoxybenzoyl isothiocyanate with tryptophane(1:1), The ligand was characterized by elemental microanalysis C.H.N.S, FT-IR, UV-Vis and 1H,13C NMR spectra, Some transition metals complexes of this ligand were prepared and characterized by FT-IR, UV-Vis spectra, conductivity measurements, magnetic susceptibility and atomic absorption, From obtained results the molecular formula of all prepared complexes were [M(MTP)2] (M+2 =Mn, Co, Ni, Cu, Zn, Cd and Hg), the proposed geometrical structure for all complexes were tetrahedral except copper complex has a square planer geometry around metallic ion
... Show MoreIn this investigation, the mechanical properties and microstructure of Metal Matrix Composites (MMCs) of Al.6061 alloy reinforced by ceramic materials SiC and Al2O3 with different additive percentages 2.5, 5, 7.5, and 10 wt.% for the particle size of 53 µm are studied. Metal matrix composites were prepared by stir casting using vortex technique and then treated thermally by solution heat treatment at 530 0C for 1 hr. and followed by aging at 175 0C with different periods. Mechanical tests were done for the samples before and after heat treatment, such as impact test, hardness test, and tensile test. Also, the microstructure of the metal matrix composites was examine
... Show MoreThis study focuses on producing wood-plastic composites using unsaturated polyester resin reinforced with Pistacia vera shell particles and wood industry waste powder. Composites with reinforcement ratios of 0%, 20%, 30%, and 40% were prepared and tested for thermal conductivity, impact strength, hardness, and compressive strength. The results revealed that thermal conductivity increases with reinforcement, while maintaining good thermal insulation, reaching a peak value of 0.633453 W/m·K. Hardness decreased with increased reinforcement, reaching a minimum nominal hardness value of 0.9479. Meanwhile, impact strength and compressive strength improved, with peak values of 14.103 k/m² and 57.3864568 MPa, respectively. The main aim is to manu
... Show MoreIn this work the corrosion behavior of Al metal was studied by using non- destructive testing (NDT), which is a noninvasive technique for determining the integrity of a material. The ultrasonic waves was used to measure the corrosion which occur by two corrosive medium (0.1N sodium chloride and 0.1N sodium hydroxide) and study the corrosion by weight-loss method and electrochemical method in addition to performance the microscopic inspection for the samples before and after the immersion in the corrosive medium. Corrosion parameters were interpreted in these media which involve corrosion potential (Ecorr) and corrosion current density (icorr). The results indicate that both
... Show MoreMannich base is a versatile compound that can be easily modified to introduce different functional groups, allowing for the creation diverse selection of items with varying features. Additionally, the Mannich reaction is a valuable tool in organic synthesis, due to the fact it provides an effortless and efficient approach for synthesizing C-N bonds. Overall, The Mannich base and even its derivatives are essential in many aspects of chemistry and its complexes are in the pharmaceutical industry. Studies have revealed that it shows good anti-cancer, anti-mycobacterial, remarkable anti-HIV, anti-tubercular, anti-convulsant, anti-fungal, antiviral, antitumor, cytotoxic activities and in industrial applications such as in the creation of polymer
... Show MoreIn this study, the preparation and characterization of hyacinth plant /chitosan composite, as a heavy metal removal, were done. Water hyacinth plant (Eichhorniacrasspes) was collected from Tigris river in Baghdad. The root and shoot parts of plant were ground to powder. Composite materials were prepared at different ratios of plant part (from 2.9% to 30.3%, wt /wt) which corresponds to (30-500mg) of hyacinth plant (root and shoot) and chitosan. The results showed that all examined ratios of plant parts have an excellent absorption to copper (Cu (II)). Moreover, it was observed that 2.9% corresponds (30mg) of plant root revealed highest removal (82.7%) of Pb (II), while 20.23% of shoot removed 61% of Cd (II) within 24 hr
... Show MoreThis study is included the preparation of two tetradentate amide-thiol proligands of the general structure [H2Ln], [where; (n = (1–2)]. The ligands [H2L1] and [H2L2] have been prepared from the reaction of the cyclic thioester 2-oxo-1, 4-dithiacyclohexane (compound 1) and 3-chloro-2-oxo-1, 4 dithiacyclohexane (compound 2) with 2-aminomethanepyridine in (1:1) ratio respetively. The reaction was carried out in chloroform at room temperature and under N2 atmosphere. Structural formula of these two ligands have been reported.
As they include both nucleophilic and electrophilic moieties on the same skeleton, enaminones are an important subclass of chemical compounds that contain conjugated NC=CC=O fragments. These active sites aid in the production of organic molecules containing linear or cyclic heteroatoms. Enaminones and the chemica1 compounds produced from them are both biologically active against the most dangerous bacteria. As a result, they have been utilized as starting materials for the synthesis of anti-inf1ammatory, antibacteria1, anticonvulsant, anticancer, anti-urease, anti-malaria1, optically luminescent, corrosion inhibition, and antitumor agents. Their synthesis has usually a terrific deal of interest and a plethora of synthetic paths have been na
... Show MoreNew isatinic hydrazone Schiff-base ligands, namely furan-2-carboxylic acid (2-oxo-1,2-dihydro-indol- 3-ylidene)-hydrazide (L1), thiophene-2-carboxylic acid (2- oxo-1,2-dihydro-indol-3-ylidene)-hydrazide (L2) and 2-(pyridine-2-yl-hydrazono)-1,2-dihydro-indol-3-one) (L3) are reported. The ligands were prepared by the condensation of furan-2-carboxylic acid hydrazide (L1), thiophene- 2-carboxylic acid hydrazide (L2), and 2-hydrazino pyridine (L3) with isatine. Monomeric complexes were prepared from the reaction of the corresponding metal chloride with the ligands. The ligands and their nine new complexes of the general formulae [M(Ln)2]Cl2 [where M = Co(II), Zn(II) and Cd(II); n = L1, L2 and L3] were characterised by spectroscopic methods (FTI
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