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This experiment was implemented to study the physical and mechanical properties of Medium Density Fiberboard (MDF) manufactured from Old Corrugated Containers OCCs using three variables including density of board (0.6 g/cm3 and 0.7 g/cm3), resin content of urea-formaldehyde (8 %, 10 % and 12 %) and pressing time (25, 30 and 35 minutes). Results showed that board density proved to be an important factor affecting MDF manufacturing, board density showed significant effects on both Modulus Of Elasticity (MOE) and Modulus Of Rapture (MOR), while it had no significant effect on Internal Bonding (IB), higher board density (0.7 g/cm3) surpass low board density (0.6 g/cm3). The percent resin content and press time gave a significant effect on mechanical properties except IB. Also, it was noticed a perfection of boards combined at 12% resin contents and 30 minutes of mechanical properties. The triple intercourse between main effects showed to be significant for MOR, MOE and IB, generally boards made of higher density (0.7 g/cm3) with 12% resin content at pressing time 30 minutes developed better mechanical properties than other boards. According to the physical properties, board density showed a significant effect on Water Absorption (WA), Thickness Swelling (TS) and Linear Expansion (LE) after 2 and 24 hours of submersion in water. The resin content at 12 % and pressing time at 30 minutes showed better mechanical and physical properties.

The presented study examines the effect of SBR polymer latex on the performance of concrete composite containing (1%MgO powder + 0.75%polyolefin fibers). In this study, the amount of added latex to concrete composite was varied. Density, compressive strength, and flexural strength were measured. The results showed that SBR addition caused a reduction in compressive strength with increase the dosage of adding. Flexural strength at 28 days improved with increase of SBR dosage (2%, 4% and 6%) and the results recorded.

In recent years, many researchers used polymethyl methacrylate in dental applications due to good mechanical and physical properties. In this research, the eggshell powder had mixed with polymethyl methacrylate resin for the preparations of new composite materials have good mechanical properties and low cost compared with industrially processed powders. The hand lay-up technique was adopted for the preparation specimens composite materials that made from a polymethyl methacrylate as a matrix with (1%, 3%, 5% and 7%) weight fraction eggshell powder (before and after burning) a reinforcement material. The mechanical properties were analyzed by utilizing (SPSS) according to (One-Way ANOVA). The results showed that the addition of the eggshell (before and after burning) powder at a ratio of (7% weight fraction) improves the values of tensile properties and fracture toughness, while this ratio leads to a decrease in values of elongation percentage at break and impact strength compared with other specimens. Also, the results showed that the Sig value was lower in all mechanical properties of specimens reinforced with eggshell powder after burning than specimens reinforced with eggshell powder before burning with a polymethyl methacrylate resin, where the percentage of improvement was in ultimate tensile strength 64 %, modulus of elasticity 13 %, elongation percentage 6 %, impact strength 75% and 81% fracture toughness.

In the present paper, the growth rate of the central index of the composition of two integral functions in terms of the left and right factors are discussed.

Abstract Aims: The aim of this study was to evaluate the shear bond strength of brackets bonded to composite restorations using four types of surface conditioning procedure. Materials and Methods: Thirty two cylindrical cavities were made at the center of self-cured acrylic resin blocks. All cavities were then filled with composite resin. The specimens were randomly divided into four groups. Group one: Composite surface was acid etched with 37% phosphoric acid. Group two: After using 37% phosphoric acid, bonding agent was applied and cured. Group three: After using 37% phosphoric acid silane coupling agent was applied then bonding agent was applied. Group Four: The composite surface roughened with a diamond bur, and then 37% phosphoric acid was applied. Brackets were bonded onto the composite prepared samples with Transbond XT. Shear Bond Strength was measured by a universal testing machine. KruskalWallis test was utilized for data analysis. Results: There was a significant difference between the four groups. The highest bond strength was that of Group 3. Group 1 had the lowest bond strength. Conclusions: Roughening the composite surface before acid etching was effective to improve the bond strength of orthodontic brackets to composite restorations. Addition of silane before bonding agent application result in highest bond strength.

Aims: To evaluate the Absorbance and transmittance of the optical light for three different types of light activated dental composite resin stored in artificial saliva. Materials and Methods: 30 specimens were prepared from light activated composite resin and divided in to three groups, G1: 10 specimens prepared from Els, G2: 10 specimens prepared from Tetric n Ceram, G3: 10 specimens prepared from Solitaire2. Absorbance of the optical light measured using spectrophotometer. The specimens were evaluated after (zero,1,7,28) day immersion time in artificial saliva. Results: Statistical analysis shows significant difference at P ≤ 0.05 among tested groups at same immersion time, Solitaire 2 showed highest absorbance means compare to Tetric, Els specially after 1 day immersion in artificial saliva. No significant difference P> 0.05 in absorbance mean at various immersion time in artificial saliva for each group. Els shows low absorbance and highest transmittance percentage T% than Tetric and Solitaire composite resin. Conclusion: The Els extra composite resin has lowest absorbance and highest transmittance means for optical light, Solitaire2 showed more absorbance means with less amount of light transmittance through the composite resin compare to Tetric and Els. The performance of the experimented groups statistically not significant in terms of immersion time in artificial saliva.

To decrease the dependency of producing high octane number gasoline on the catalytic processes in petroleum refineries and to increase the gasoline pool, the effect of adding a suggested formula of composite blending octane number enhancer to motor gasoline composed of a mixture of oxygenated materials (ethanol and ether) and aromatic materials (toluene and xylene) was investigated by design of experiments made by Mini Tab 15 statistical software. The original gasoline before addition of the octane number blending enhancer has a value of (79) research octane number (RON). The design of experiments which study the optimum volumetric percentages of the four variables, ethanol, toluene, and ether and xylene materials leads to 30 experiments. The results obtained show that RON can reach a value of 103.1 (30.5% RON improvement) when a formula of composite octane number blending enhancer containing a volumetric percentage of 15, 25, 25 volumetric percent of ethanol, toluene and xylene respectively. The cost study in comparison with the price of high octane number gasoline sold in Iraq show that this formula has a high cost of 2050 Iraqi Dinar (IQD)/liter gasoline, while the formula of composite octane number blending enhancer containing 15% volumetric percentage of Ethanol only leading to gasoline of 89.6 RON (13.4 % ON improvement) gave minimum cost of 300 IQD / liter gasoline for the blend of octane number enhancer making the total price of the gasoline to be competitive with the high ON gasoline imported from outside Iraq. While the formula of 7.5, 12.5, 37.5 and 5% volumetric percentage of ethanol, toluene, xylene, and ether respectively have a maximum cost of 2525 IQD of produced gasoline of 101.3 RON (octane number improved by 28.23%).

Aims: This study investigated the effect of polishing times (immediately, 1 hour and 24 hour after light curing) and staining solutions on the color stability of two composite resins. Materials and Methods: Nanocomposite (Filtek Z350) and microhybrid composite (Valux plus) were used. Sixty discs (8mm diameter×2mm height) were made for each composite, and divided into four groups: the first group was polished immediately after light curing; second group was polished after 1 h; third group was polished after 24 h of curing; and the fourth group was the control. Color was measured with spectrophotometer. After baseline color measurements, the specimens of each group divided into three subgroups; specimens of first subgroup were immersed in coffee; specimens of second subgroup were immersed in orange juice; specimens of third subgroup were immersed in distilled water, after 7 day of immersion, the color was measured again and ΔE were calculated. Statistical analysis: Two-way ANOVA, Duncan's Multiple Range test and t-test. Results: The influence of polishing times and staining solutions on color change was significant. Polishing 24 hours after curing presented lowest ΔE value. Coffee promoted more color change than orange juice and distilled water, Filtek Z350 showed lower ΔE than Valux plus. Conclusions: Immediate polishing negatively affect the color stability of composite resins, coffee had a significant influence on discoloration of composite resins. The nanocomposite showed higher color stability than microhybrid composite.

Friction stir processing (FSP) is a new solid state technique, it is employed for theimprovement of the mechanical properties of a material and the production of surface layercomposites instead of conventional processing technologies. This research aims to study theability of applying Friction Stir Processing (FSP) to modify the surface of high densitypolyethylene (HDPE) reinforcing by B4C with a particle size of 0.4?m, Groove in themiddle of HDPE surface made to fill by B4C. Varity in the groove depth (0.6, 1.2 and1.8)mm used according to B4C ratio on HDPE substrate particles. Friction stir process wascarried out, using tool with cylindrical shape of pin and shoe tool to produce surface layercomposite. The effect of processing parameters including rotational and transverse speeds onthe mechanical properties of composite layer was studied. Wear test results show apronounced improvement in wear resistance of HDPE surface through reinforcementadditions of B4C at a ratio (5%, 10% and 15% ), where wear rate improved by (60%, 71%and 63%) respectively, as compared with as received HDPE, the surface compositeHDPE/B4C have good wear resistance. Hardness test results indicate that the hardness ofcomposite layer reinforced with (5%,10% and 15%) particles improved by( 26%, 35% and28% )respectively as compared with received HDPE. OM revealed that high tool rotationalspeed resulted in homogeneous distribution of B4C particles and vice versa.

Magnesium oxide (MgO) is regarded as a biocompatible material. A composite material fromMgO oxide prepared by mixing MgO powder with TiO2 (rutile phase) (2, 5, 10)Wt.% usingpowder metallurgy technique. It is used to be bioceramic material. The compressed sampleswere dried and sintered at (1200) ᵒC. porosity measurement showed that the porositydecreasing with increasing TiO2% . X-ray showed the presence of Mg2TiO4 in the compositestructure of MgO with (5, 10)%TiO2 samples.The mechanical study showed an increasing in compressive strength, hardness, wearresistance and biodegradation resistance with increasing TiO2% content in the limit of usedpercentage. The prepared composite material didn’t present antibacterial activity whileprevious researches showed opposite result because of using nanoscale particle size of MgO.

Two different composite materials were prepared by stir casting method of AA 6061 alloy as a matrix reinforced with two addition different ceramic materials Al2O3 and B4C of grain size 20 µm by 2.5, 5, 7.5 and10% in weight. The composite material with aluminum alloy as a matrix possesses a unique mechanical properties such as: high specific strength and hardness, low density, and high resistance to corrosion and friction wear. This composite is widely used in automotive parts space and marine applications. Pin-on-disc technique was used to calculate the wear rate for each addition of Al2O3 and B4C particles. Rockwell hardness test and optical micrographs examinations were carried out to analyze, compare, and evaluate the addition of reinforced particles. The results of this investigation appeared that the 7.5% of ceramic particles addition give highest values of the hardness and wear resistance.

This paper deals with finite element modeling of the ultimate load behavior of double skin composite (DSC) slabs. In a DSC slab, shear connectors in the form of nut bolt technique studs are used to transfer shear between the outer skin made of steel plates and the concrete core. The current study is based on finite element analysis using ANSYS Version 11 APDL release computer program. Experimental programmes were carried out by the others, two simply supported DSC beams were tested until failure under a concentrated load applied at the center. These test specimens were analyzed by the finite element method and the analyses have shown that these slabs displayed a high degree of flexural characteristics, ultimate strength, and ductility. The close agreement has been observed between the finite element and experimental results for ultimate loads and load–deflection responses. The finite element model was thus found to be capable of predicting the behavior of DSC slabs accurately.

Aim: To evaluate the surface roughness of three different types of light activated composite resin using (Sof-Lex) – polishing system, a profilometer study. Materials and Methods: A total of 30 resin composite disks were prepared from three different types of composite resin include 3 – groups. Group I: 10 specimens were prepared from light activated nano hybride (Tetric n – Ceram, Ivoclar – Vivadent – Liechtenstein). Group II: 10 specimens were prepared from light activated microhybride composite resin (Arabesk – Voco, Germany). Group III: 10 specimens were prepared from light activated poly-glas composite resin (Solitaire – 2, Heraeus, Kulzer, Germany). The resin blocks finished and polished using (Sof – Lex) polishing system. The specimens were analyzed for surface roughness using “Profilometer”. Results: Tetric n – Ceram composite resin showed the lowest roughness average (0.112 μm) followed by Arabesk composite (0.150 μm), Solitaire – 2 composite resin showed the highest roughness average (0.341 μm). Conclusions: Tetric n– Ceram (nano-hybride) was the best polished composite resin, showed the least roughness average.

Aim of this study is to investigate the effect of Er: YAG Laser, the sand blasted with aluminum oxide and wearing with diamond bur as a surface treatment to the bond strength of repaired composite resin after aged. Materials and Methods: Sixty Teflon mold (4mm×2mm), of Tetric® Ceram prepared. The specimens were randomly separated into six groups and undergo the following surface treatments: G1 no treatment (control), G2-G4 treated with a different amount of laser energy (40, 60, 80 mJ Er: YAG laser respectively) under a 2Hz frequency, G5 wearing with diamond bur, and G6 sandblasted with 50μm aluminum oxide. All 6 groups divided into two subgroups,1st control,2ed etched with 37% phosphoric acid. Bonding material was applied and the second split of Teflon mold (4mm×1mm) placed onto the prepared specimen, filled with Tetric N-Ceram. The shear test was done using the Uni-versal testing machine. Results: Significant differences of all variables, laser 60,40mj surface treatment displayed superior shear strength (45.24, 45.03 MPa respectively), aluminum oxide showed low shear value (32.48 MPa). Phosphoric acid showed the highest shear value (40.47 MPa) in compare to the control one (31.62 MPa). Conclusions: Using of Er:YAG laser improve the shear value of repaired composite in comparing with a diamond bur and aluminum oxide. Conditioning aged composite surface with a phosphoric acid enhancing its adhesive result.

Aim of Study: This in vitro study was conducted to evaluate the shear bond strength of intra oral por-celain repair system using 10% sodium hypochlorite and different acid etch. Materials and methods: Forty specimens were prepared in form of metal disks (8mm in diameter, 15mm height) and porcelain was applied according to the manufacturer instructions.The specimens randomly divided into 4 equal groups. In Group I ,II the samples were treated with 9% hydrofluoric acid for one minute. While groups III, IV were treated with 37% phosphoric acid for one minute, after washing the specimens with water and dryness, groups II, III the surfaces treated with 10%sodium hypochlorite for one minute while group I and IV leaved untreated. After that, the surfaces of all samples were washed and dried and silane coupling agent (MonoBond-S Vivadent, Liechtenstein) was applied according to the manu-facturer instructions, then bonding agent (Excite) (Vivadent, Liechtenstein) and composite (tetric N–ceram) (Vivadent, Liechtenstein) were applied according to the manufacturer instructions. All the sam-ples were stored in normal physiological saline for 7 days. Then the samples were thermocycled ma-nually between two water baths After that Shear bond strength was tested using universal testing ma-chine. Results: using ANOVA and Duncan’s multiple range tests. The result showed that there was highly significant difference between groups treated with 10%sodium hypochlorite with untreated one. There was significant difference between samples acid etched using hydrofluoric acid with those etched with phosphoric acid. Conclusions: Sodium hypochlorite and hydrofluoric acid significantly increase the shear bond strength between composite resin and porcelain fused to metal specimens

The study was conducted to determine reducing & non reducing sugars and lysine content of three species ( Sham , ILB and Aquadulce ) of Broad bean seed flour ( Vicia faba ) which obtained from ICARDA Ninevah / Iraq and were compared with those of wheat flour. Different types of composite flour were prepared by partial substation of wheat flour with10, 20 and 30 % of Broad bean flour, also to study the effect of their content of reducing sugars and lysine on Brown index and Fermentation pressure gas. The content of wheat flour from non reducing and reducing sugars was 1.31 and 0.17% respectively, their content in sham broad bean flour was 4.13and 0.37% respectively, and for ILB specie was 4.21and 0.31% respectively , and for Aquadulce specie was 4.20and 0.39 % respectively, lysine content of wheat flour was 1.85mg /100gm and their content in sham , ILB and Aquadulce flour was402, 416 and 420 mg / 100 gm respectively. Result of study showed that the fermentation pressure gas values of composite dough increased with increasing substation ratio of all species of broad bean used in this study. Adding broad bean flour of three species to wheat flour caused increasing in brown index of composite flour comparing with wheat flour and caused color darkening of baked products from composite flour ( lab loaf ، cake and biscuit ).

Aims: To evaluate the effect of different surface treatment on the microleakage of repaired CI V com-posite resin restoration. Materials and methods: This study was performed in vitro on 20 caries free premolar teeth. Standardized class V cavity preparation on buccal and lingual surfaces of each tooth was done, forty cavities cleaned with distilled water and dried, then the cavities were filled with the composite. After that, all teeth were stored in normal saline for 3 months, so that the filling become old then remove 1mm of composite from all cavities. The cavities were divided into four groups. The first two groups were treated with 37% phosphoric acid. The other groups treated with 9% hydrofluoric acid the groups II and IV were treated with silane coupling agent, then all cavities were filled with compo-site after 5th generation bonding agent were applied .The teeth were stored for one week after that the Samples were thermocycled and immersed in methylene blue dye, The samples were sectioned, and examined using stereomicroscope. Results: Samples treated with silane coupling agent showed less microleakage than those without silanation. There was highly significant difference between samples acid etched using hydrofluoric acid with those etched with phosphoric acid. Conclusions: Silane coupling agent and the hydrofluoric acid significantly decreased microleakage of repaired CI V compo-site resin restoration.

Aims: To evaluate the effect of immersion periods in artificial saliva on the surface roughness of an arch wire. Materials and Methods: The roughness of three types of orthodontic arch wires: stainless steel (SS), titanium molybdenum alloy (TMA) and composite coated wire (CC) were first measured at dry condition then incubated in artificial saliva at 37 o C with saliva pH (7.25) for different immersion periods (1, 14 and 28 days). Then the surface roughness was measured by using Taylor Hobson Profi-lometer (Talysurf type 10). Results: There was a significant increase in surface roughness of the three types of wires during the first day of immersion but as the immersion periods increased, it showed a non significant difference in the roughness of SS and TMA. The roughness of CC however, increased. Conclusions: It was concluded that the surface roughness of SS and TMA wires increased during the first day of immersion, such increase is not significant after that, while in case of CC, as the immersion periods increase the surface roughness significantly increased.

The aim of this study was to determine the effect of storage time on shear bond strength of three composite resin, two utilize total etch technique and one utilize self etching bonding agent. One hundred twenty maxillary and mandibular molars were used in this study. The teeth were prepared by cutting the occlusal enamel with diamond bur to expose dentin and ground wet with silicone carbide papers. The specimens were then divided into three groups and stored in distilled water. Scotchbond Multipurpose Plus was used in the first group and a stainless steel round mould, with a central hole of 4 mm in diameter and 2 mm in height was used to build up the composite Z100. The composite resin was inserted in two increments, each one was light cured for 40 seconds. This gro-up is divided into four subgroups each of ten according to the storage time (one day, fifteen days, three months and six months) then stored in distilled water accordingly. The same procedure was repeated in the second and third groups. The composite used in the second group was Tetric with Excite bonding agent. In the third group, Definite composite and its bonding agent Etch and Prime was used. The bond strength was measured and the data were statistically analyzed. Z100 composite had the greatest shear bond strength followed by Tetric and Definite. One day and fifteen days storage time for all types of composite had greater shear bond strength than the three months and six months storage time. In conclusion there was a gradual decrease in bond strength with increased storage time up to six months irrespective of the type of composite.